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diff --git a/COPYING b/COPYING
new file mode 100644
index 0000000..8add30a
--- /dev/null
+++ b/COPYING
@@ -0,0 +1,504 @@
+		  GNU LESSER GENERAL PUBLIC LICENSE
+		       Version 2.1, February 1999
+
+ Copyright (C) 1991, 1999 Free Software Foundation, Inc.
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+
diff --git a/GrokHtml.c b/GrokHtml.c
new file mode 100755
index 0000000..2314336
--- /dev/null
+++ b/GrokHtml.c
@@ -0,0 +1,343 @@
+/* GrokHtml.c - Tree expression language JNI interface source file
+ + Copyright (C) 2005 Dell, Inc.
+ + Authors: David Barksdale <amatus@ocgnet.org>
+ +
+ +  This library is free software; you can redistribute it and/or
+ +  modify it under the terms of the GNU Lesser General Public
+ +  License as published by the Free Software Foundation; either
+ +  version 2.1 of the License, or (at your option) any later version.
+ +
+ +  This library is distributed in the hope that it will be useful,
+ +  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ +  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ +  Lesser General Public License for more details.
+ +
+ +  You should have received a copy of the GNU Lesser General Public
+ +  License along with this library; if not, write to the Free Software
+ +  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <ctype.h>
+#include <string.h>
+#include <jni.h>
+#include <libxml/HTMLtree.h>
+#include <libxml/HTMLparser.h>
+#include "treexpr.h"
+#include "GrokHtml.h"
+
+#ifdef HTML_PARSE_RECOVER
+#define PARSER_OPTIONS	( HTML_PARSE_RECOVER | HTML_PARSE_NOERROR | HTML_PARSE_NOWARNING )
+#else
+#define PARSER_OPTIONS	( HTML_PARSE_NOERROR | HTML_PARSE_NOWARNING )
+#endif
+
+#if 0
+/* 64-bit machine */
+#define JLONG_TO_POINTER( x )	((void *)( x ))
+#define POINTER_TO_JLONG( x )	((jlong)( x ))
+#else
+/* 32-bit machine */
+#define JLONG_TO_POINTER( x )	((void *)(int)( x ))
+#define POINTER_TO_JLONG( x )	((jlong)(int)( x ))
+#endif
+
+/*
+ * Class:     GrokHtml
+ * Method:    FreeMachine
+ * Signature: (J)V
+ */
+JNIEXPORT void JNICALL Java_GrokHtml_FreeMachine( JNIEnv *env, jobject obj, jlong Machine )
+{
+	free_machine((struct machine *)JLONG_TO_POINTER( Machine ));
+}
+
+/*
+ * Class:     GrokHtml
+ * Method:    ParseExpression
+ * Signature: (Ljava/lang/String;)J
+ */
+JNIEXPORT jlong JNICALL Java_GrokHtml_ParseExpression( JNIEnv *env, jobject obj, jstring Expression )
+{
+	const char *expr, *residue;
+	struct machine *m;
+
+	expr = (char *)(*env)->GetStringUTFChars( env, Expression, JNI_FALSE );
+	residue = parse_treexpr( expr, &m );
+	if( residue == NULL )
+	{
+		jclass exc;
+		jmethodID id;
+		jstring message;
+		jobject ex;
+
+		/*
+		 * There was an error parsing, throw Java exception
+		 */
+
+		/* First lookup the java.text.ParseException class */
+		exc = (*env)->FindClass( env, "java/text/ParseException" );
+		if( exc == NULL )
+			return 0;
+
+		/* Grab the method ID for the constructor: ParseException( String s, int errorOffset ) */
+		id = (*env)->GetMethodID( env, exc, "<init>", "(Ljava/lang/String;I)V" );
+		if( id == 0 )
+			return 0;
+
+		/* Convert the error message from the parser to a java string object */
+		message = (*env)->NewStringUTF( env, m->error );
+
+		/* Create the exception object */
+		/* NB: m->buf is a pointer into the origional string where the error occured, so we
+		   take the difference from expr to find errorOffset, this will not be accurate if
+		   the string contained any non-ASCII characters */
+		ex = (*env)->NewObject( env, exc, id, message, (jint)( m->buf - expr ));
+
+		/* Throw it */
+		(*env)->Throw( env, ex );
+
+		/* Free the left-over memory used by the parser */
+		free_machine( m );
+		(*env)->ReleaseStringUTFChars( env, Expression, expr );
+		return 0;
+	}
+
+	/*
+	 * If residue is an empty string here then the entire thing was read as an expression.
+	 * It might be considered an error if there is some stuff left over, but it also might
+	 * be usefull to ignore it to be a little more robust. For now it's ignored.
+	 */
+
+	/* Clean up and return the pointer as a long */
+	(*env)->ReleaseStringUTFChars( env, Expression, expr );
+	return POINTER_TO_JLONG( m );
+}
+
+/*
+ * Class:     GrokHtml
+ * Method:    FreeDocument
+ * Signature: (J)V
+ */
+JNIEXPORT void JNICALL Java_GrokHtml_FreeDocument( JNIEnv *env, jobject obj, jlong Document )
+{
+	xmlFreeDoc((htmlDocPtr)JLONG_TO_POINTER( Document ));
+}
+
+/*
+ * Class:     GrokHtml
+ * Method:    OpenDocumentFromURI
+ * Signature: (Ljava/lang/String;)J
+ */
+JNIEXPORT jlong JNICALL Java_GrokHtml_OpenDocumentFromURI( JNIEnv *env, jobject obj, jstring URI )
+{
+	const char *uri;
+	htmlDocPtr doc;
+
+	uri = (char *)(*env)->GetStringUTFChars( env, URI, JNI_FALSE );
+	doc = htmlReadFile( uri, NULL, PARSER_OPTIONS );
+	(*env)->ReleaseStringUTFChars( env, URI, uri );
+	if( doc == NULL )
+	{
+		jclass exc;
+
+		/* Throw a runtime exception */
+		exc = (*env)->FindClass( env, "java/lang/RuntimeException" );
+		if( exc == NULL )
+			return 0;
+
+		(*env)->ThrowNew( env, exc, "Error opening HTML document" );
+		return 0;
+	}
+	return POINTER_TO_JLONG( doc );
+}
+

+/*

+ * Class:     GrokHtml

+ * Method:    OpenDocumentFromBytes

+ * Signature: ([B)J

+ */

+JNIEXPORT jlong JNICALL Java_GrokHtml_OpenDocumentFromBytes( JNIEnv *env, jobject obj,

+	jbyteArray Bytes )

+{

+	jsize len;

+	jbyte *bytes;

+	htmlDocPtr doc;

+

+	len = (*env)->GetArrayLength( env, Bytes );

+	bytes = (*env)->GetByteArrayElements( env, Bytes, NULL );

+	doc = htmlReadMemory((char *)bytes, len, NULL,	NULL, PARSER_OPTIONS );

+	(*env)->ReleaseByteArrayElements( env, Bytes, bytes, JNI_ABORT );

+	if( doc == NULL )

+	{

+		jclass exc;

+

+		/* Throw a runtime exception */

+		exc = (*env)->FindClass( env, "java/lang/RuntimeException" );

+		if( exc == NULL )

+			return 0;

+

+		(*env)->ThrowNew( env, exc, "Error opening HTML document" );

+		return 0;

+	}

+	return POINTER_TO_JLONG( doc );

+

+}

+
+/*
+ * Class:     GrokHtml
+ * Method:    OpenDocumentFromString
+ * Signature: (Ljava/lang/String;)J
+ */
+JNIEXPORT jlong JNICALL Java_GrokHtml_OpenDocumentFromString( JNIEnv *env, jobject obj,

+	jstring Document )
+{
+	const char *document;
+	htmlDocPtr doc;
+
+	document = (char *)(*env)->GetStringUTFChars( env, Document, JNI_FALSE );
+	doc = htmlReadMemory( document, strlen( document ), NULL,
+		NULL, PARSER_OPTIONS );
+	(*env)->ReleaseStringUTFChars( env, Document, document );
+	if( doc == NULL )
+	{
+		jclass exc;
+
+		/* Throw a runtime exception */
+		exc = (*env)->FindClass( env, "java/lang/RuntimeException" );
+		if( exc == NULL )
+			return 0;
+
+		(*env)->ThrowNew( env, exc, "Error opening HTML document" );
+		return 0;
+	}
+	return POINTER_TO_JLONG( doc );
+}
+
+/*
+ * Class:     GrokHtml
+ * Method:    SearchDocument
+ * Signature: (JLjava/lang/String;J)Ljava/lang/String;
+ */
+JNIEXPORT jstring JNICALL Java_GrokHtml_SearchDocument( JNIEnv *env, jobject obj, jlong Document,
+	jstring Pattern, jlong Machine )
+{
+	const char *pattern;
+	struct match *z;
+	struct regex_match **re, *cur;
+	char *buf;
+	jstring retval;
+	int i, j, k, sub, len;
+
+	/* Search the document */
+	z = document_process((struct machine *)JLONG_TO_POINTER( Machine ),
+		(htmlDocPtr)JLONG_TO_POINTER( Document ));
+	if( z == NULL )
+	{
+		jclass exc;
+
+		/* Throw a runtime exception */
+		exc = (*env)->FindClass( env, "java/lang/RuntimeException" );
+		if( exc == NULL )
+			return NULL;
+
+		(*env)->ThrowNew( env, exc, "No match found" );
+
+		/* Clean up and return */
+		return NULL;
+	}
+
+	/* Count subexpressions */
+	pattern = (char *)(*env)->GetStringUTFChars( env, Pattern, JNI_FALSE );
+	sub = 0;
+	for( i = 0; pattern[i] != 0; i++ )
+		if( pattern[i] == '\\' && isdigit( pattern[i + 1] ) && sub < pattern[i + 1] - '0' )
+			sub = pattern[i + 1] - '0';
+
+	/* Allocate an array for matches, only enough to hold what we're going to use */
+	re = malloc( sub * sizeof( struct regex_match * ));
+	if( re == NULL )
+	{
+		jclass exc;
+
+		/* Throw an out of memory error */
+		exc = (*env)->FindClass( env, "java/lang/OutOfMemoryError" );
+		if( exc == NULL )
+			return NULL;
+
+		(*env)->ThrowNew( env, exc, "Unable to allocate memory" );
+
+		/* Clean up and return */
+		(*env)->ReleaseStringUTFChars( env, Pattern, pattern );
+		return NULL;
+	}
+
+	/* Fill in array */
+	for( i = 0, cur = z->re; cur != NULL && i < sub; cur = cur->next, i++ )
+		re[i] = cur;
+	if( i < sub )
+	{
+		jclass exc;
+
+		/* Throw an index out of bounds exception */
+		exc = (*env)->FindClass( env, "java/lang/IndexOutOfBoundsException" );
+		if( exc == NULL )
+			return NULL;
+
+		(*env)->ThrowNew( env, exc, "Not enough matches to satisfy pattern" );
+
+		/* Clean up and return */
+		free( re );
+		(*env)->ReleaseStringUTFChars( env, Pattern, pattern );
+		return NULL;
+	}
+
+	/* Calculate size of output buffer */
+	len = 1;
+	for( i = j = 0; pattern[i] != 0; i++ )
+		if( pattern[i] == '\\' && isdigit( pattern[i + 1] ))
+		{
+			sub = pattern[++i] - '1';
+			for( k = re[sub]->match.rm_so; k < re[sub]->match.rm_eo; k++ )
+				len++;
+		}
+		else
+			len++;
+
+	/* Allocate output buffer */
+	buf = malloc( len );
+	if( buf == NULL )
+	{
+		jclass exc;
+
+		/* Throw an out of memory error */
+		exc = (*env)->FindClass( env, "java/lang/OutOfMemoryError" );
+		if( exc == NULL )
+			return NULL;
+
+		(*env)->ThrowNew( env, exc, "Unable to allocate memory" );
+
+		/* Clean up and return */
+		free( re );
+		(*env)->ReleaseStringUTFChars( env, Pattern, pattern );
+		return NULL;
+	}
+
+	/* Fill in output buffer */
+	for( i = j = 0; pattern[i] != 0; i++ )
+		if( pattern[i] == '\\' && isdigit( pattern[i + 1] ))
+		{
+			sub = pattern[++i] - '1';
+			for( k = re[sub]->match.rm_so; k < re[sub]->match.rm_eo; k++ )
+				buf[j++] = re[sub]->str[k];
+		}
+		else
+			buf[j++] = pattern[i];
+	buf[j++] = 0;
+
+	/* Clean up and return the string */
+	free( re );
+	(*env)->ReleaseStringUTFChars( env, Pattern, pattern );
+	retval = (*env)->NewStringUTF( env, buf );
+	free( buf );
+	return retval;
+}
diff --git a/GrokHtml.java b/GrokHtml.java
new file mode 100755
index 0000000..a78159e
--- /dev/null
+++ b/GrokHtml.java
@@ -0,0 +1,73 @@
+/* GrokHtml.java - Tree expression language JNI interface source file
+ + Copyright (C) 2005 Dell, Inc.
+ + Authors: David Barksdale <amatus@ocgnet.org>
+ +
+ +  This library is free software; you can redistribute it and/or
+ +  modify it under the terms of the GNU Lesser General Public
+ +  License as published by the Free Software Foundation; either
+ +  version 2.1 of the License, or (at your option) any later version.
+ +
+ +  This library is distributed in the hope that it will be useful,
+ +  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ +  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ +  Lesser General Public License for more details.
+ +
+ +  You should have received a copy of the GNU Lesser General Public
+ +  License along with this library; if not, write to the Free Software
+ +  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+class GrokHtml {
+	/*
+	 * Free memory associated with a machine pointer
+	 */
+	public native void FreeMachine( long Machine );
+
+	/*
+	 * Compile a tree expression into a machine, we return a machine pointer for use
+	 * with the SearchDocument function
+	 */
+	public native long ParseExpression( String Expression )
+		throws java.text.ParseException;
+
+	/*
+	 * Free memory associated with an document pointer
+	 */
+	public native void FreeDocument( long Document );
+
+	/*
+	 * Open an HTML document from the specified URI, for example http://example.com/file.html
+	 * we return a document pointer for use with the SearchDocument function
+	 */
+	public native long OpenDocumentFromURI( String URI )
+		throws java.lang.RuntimeException;
+

+	/*

+	 * Parse a byte[] as an HTML document, we return a document pointer for use with

+	 * the SearchDocument function

+	 */

+	public native long OpenDocumentFromBytes( byte[] Document )

+		throws java.lang.RuntimeException;

+
+	/*
+	 * Parse a string as an HTML document, we return a document pointer for use with
+	 * the SearchDocument function. You might run into some character set problems

+	 * using this function; for best results use OpenDocumentFromBytes using the exact

+	 * bytes returned from the web server
+	 */
+	public native long OpenDocumentFromString( String Document )
+		throws java.lang.RuntimeException;
+
+	/*
+	 * Search the given Document using the given Machine, the resulting matches are
+	 * are copied into a new string using the Pattern string as a template
+	 */
+	public native String SearchDocument( long Document, String Pattern, long Machine )
+		throws java.lang.RuntimeException, java.lang.OutOfMemoryError,
+		java.lang.IndexOutOfBoundsException;
+
+	/*
+	 * These native functions are defined in GrokHtml.dll (or GrokHtml.so)
+	 */
+	static { System.loadLibrary( "GrokHtml" ); }
+}
\ No newline at end of file
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..589cbfa
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,57 @@
+# Commands to use
+# for linux or freebsd or probably cygwin:
+CC = gcc
+RM = rm -f
+JAVA = java
+JAVAC = javac
+JAVAH = javah
+
+# Shared object prefix and suffix
+# for linux:
+LIB = lib
+DOTSO = .so
+# for windows or cygwin:
+# LIB = 
+# DOTSO = .dll
+
+# Source files
+SOURCES = regex/regcomp.c regex/regerror.c regex/regexec.c regex/regfree.c \
+	treexpr.c GrokHtml.c
+
+# libxml2 flags
+XMLINCL = $(shell xml2-config --cflags)
+XMLLIBS = $(shell xml2-config --libs)
+
+# java flags
+# for linux using SUN jdk15:
+# JAVAINCL = -I/opt/jdk-1.5.0/include -I/opt/jdk-1.5.0/include/linux
+# for linux using sablevm:
+JAVAINCL = -I/usr/include/sablevm
+# for freebsd using jdk15 from portage:
+# JAVAINCL = -I/usr/local/jdk1.5.0/include -I/usr/local/jdk1.5.0/include/freebsd
+
+INCL = -I./regex $(XMLINCL) $(JAVAINCL)
+LIBS = $(XMLLIBS)
+CFLAGS += -O2 -Wall
+
+all: $(LIB)GrokHtml$(DOTSO)
+
+GrokHtml.h: GrokHtml.class
+	$(JAVAH) -classpath . -jni -o $@ GrokHtml
+
+GrokHtml.class: GrokHtml.java
+	$(JAVAC) $<
+
+TestIt.class: TestIt.java
+	$(JAVAC) $<
+
+$(LIB)GrokHtml$(DOTSO): $(SOURCES) GrokHtml.h
+	$(CC) $(LIBS) $(CFLAGS) $(INCL) -shared -o $@ $(SOURCES)
+
+test: $(LIB)GrokHtml$(DOTSO) TestIt.class
+	LD_LIBRARY_PATH=$(LD_LIBRARY_PATH):. $(JAVA) TestIt
+
+clean:
+	$(RM) $(LIB)GrokHtml$(DOTSO) 
+	$(RM) GrokHtml.h
+	$(RM) *.class
diff --git a/TestIt.java b/TestIt.java
new file mode 100755
index 0000000..74088d1
--- /dev/null
+++ b/TestIt.java
@@ -0,0 +1,172 @@
+class TestIt
+{	
+	public static void main( String[] args )
+	{
+		GrokHtml foo = new GrokHtml();
+		long m1 = 0, m2 = 0, doc1 = 0, doc2 = 0;
+		String expr;
+
+		/* Parse an easy expression */
+		expr = "tr -> td -> text:\"foo = (.*)\"";
+		try
+		{
+			m1 = foo.ParseExpression( expr );
+			System.out.println( "Expression 1 parsed correctly" );
+		}
+		catch( java.text.ParseException e )
+		{
+			System.out.println( "Error parsing expression 1: " + e.getMessage( ) + "\n" + expr );
+			int i, off = e.getErrorOffset( );
+			for( i = 0; i < off; i++ )
+				System.out.print( " " );
+			System.out.println( "^" );
+		}
+
+		/* Parse another easy expression */
+		expr = "tr -> td -> text:\"bar = (.*)\"";
+		try
+		{
+			m2 = foo.ParseExpression( expr );
+			System.out.println( "Expression 2 parsed correctly" );
+		}
+		catch( java.text.ParseException e )
+		{
+			System.out.println( "Error parsing expression 2: " + e.getMessage( ) + "\n" + expr );
+			int i, off = e.getErrorOffset( );
+			for( i = 0; i < off; i++ )
+				System.out.print( " " );
+			System.out.println( "^" );
+		}
+
+		/* Parse a broken expression */
+		expr = "table<border=\"0\" foo=>";
+		try
+		{
+			long m = foo.ParseExpression( expr );
+			System.out.println( "This expression should not parse correctly" );
+		}
+		catch( java.text.ParseException e )
+		{
+			System.out.println( "Error parsing broken expression: " + e.getMessage( ) + "\n" + expr );
+			int i, off = e.getErrorOffset( );
+			for( i = 0; i < off; i++ )
+				System.out.print( " " );
+			System.out.println( "^" );
+		}
+
+		/* Open a document from a byte[] */
+		try
+		{
+			String testdoc = "<h1>Foo!</h1><h2>Bar!</h2><table><tr><td>foo = baz</td></tr></table>";
+			doc1 = foo.OpenDocumentFromBytes( testdoc.getBytes( "US-ASCII" ));
+			System.out.println( "Document opened successfully from a string" );
+		}
+		catch( java.lang.RuntimeException e )
+		{
+			System.out.println( e.getMessage( ));
+		}

+		catch( java.io.UnsupportedEncodingException e )

+		{

+			System.out.println( e.getMessage( ));

+		}
+
+		/* Open a document from a URI */
+		try
+		{
+			doc2 = foo.OpenDocumentFromURI( "test.html" );
+			System.out.println( "Document opened successfully from a URI" );
+		}
+		catch( java.lang.RuntimeException e )
+		{
+			System.out.println( e.getMessage( ));
+		}
+
+		/* Try both machines on doc 1 */
+		if( doc1 != 0 )
+		{
+			if( m1 != 0 )
+			{
+				try
+				{
+					String result = foo.SearchDocument( doc1, "foo is \\1", m1 );
+					System.out.println( "Expression 1 on doc 1: " + result );
+				}
+				catch( java.lang.RuntimeException e )
+				{
+					System.out.println( e.getMessage( ));
+				}
+				catch( java.lang.OutOfMemoryError e )
+				{
+					System.out.println( e.getMessage( ));
+				}
+			}
+
+			if( m2 != 0 )
+			{
+				try
+				{
+					String result = foo.SearchDocument( doc1, "bar is \\1", m2 );
+					System.out.println( "Expression 2 on doc 1: " + result );
+				}
+				catch( java.lang.RuntimeException e )
+				{
+					System.out.println( "This error is ok: " + e.getMessage( ));
+				}
+				catch( java.lang.OutOfMemoryError e )
+				{
+					System.out.println( e.getMessage( ));
+				}
+			}
+
+			/* Free it now that we're finished */
+			foo.FreeDocument( doc1 );
+		}
+
+		/* Try both machines on doc 2 */
+		if( doc2 != 0 )
+		{
+			if( m1 != 0 )
+			{
+				try
+				{
+					String result = foo.SearchDocument( doc2, "foo is \\1", m1 );
+					System.out.println( "Expression 1 on doc 2: " + result );
+				}
+				catch( java.lang.RuntimeException e )
+				{
+					System.out.println( e.getMessage( ));
+				}
+				catch( java.lang.OutOfMemoryError e )
+				{
+					System.out.println( e.getMessage( ));
+				}
+			}
+
+			if( m2 != 0 )
+			{
+				try
+				{
+					String result = foo.SearchDocument( doc2, "bar is \\1", m2 );
+					System.out.println( "Expression 2 on doc 2: " + result );
+				}
+				catch( java.lang.RuntimeException e )
+				{
+					System.out.println( e.getMessage( ));
+				}
+				catch( java.lang.OutOfMemoryError e )
+				{
+					System.out.println( e.getMessage( ));
+				}
+			}
+
+			/* Free it now that we're finished */
+			foo.FreeDocument( doc2 );
+		}
+
+		/* Free the machines */
+		if( m1 != 0 )
+			foo.FreeMachine( m1 );
+		if( m2 != 0 )
+			foo.FreeMachine( m2 );
+	}	
+}
\ No newline at end of file
diff --git a/regex/COPYRIGHT b/regex/COPYRIGHT
new file mode 100644
index 0000000..30c1f7a
--- /dev/null
+++ b/regex/COPYRIGHT
@@ -0,0 +1,20 @@
+Copyright 1992, 1993, 1994, 1997 Henry Spencer.  All rights reserved.
+This software is not subject to any license of the American Telephone
+and Telegraph Company or of the Regents of the University of California.
+
+Permission is granted to anyone to use this software for any purpose on
+any computer system, and to alter it and redistribute it, subject
+to the following restrictions:
+
+1. The author is not responsible for the consequences of use of this
+   software, no matter how awful, even if they arise from flaws in it.
+
+2. The origin of this software must not be misrepresented, either by
+   explicit claim or by omission.  Since few users ever read sources,
+   credits must appear in the documentation.
+
+3. Altered versions must be plainly marked as such, and must not be
+   misrepresented as being the original software.  Since few users
+   ever read sources, credits must appear in the documentation.
+
+4. This notice may not be removed or altered.
diff --git a/regex/Makefile b/regex/Makefile
new file mode 100644
index 0000000..3882b37
--- /dev/null
+++ b/regex/Makefile
@@ -0,0 +1,130 @@
+# You probably want to take -DREDEBUG out of CFLAGS, and put something like
+# -O in, *after* testing (-DREDEBUG strengthens testing by enabling a lot of
+# internal assertion checking and some debugging facilities).
+# Put -Dconst= in for a pre-ANSI compiler.
+# Do not take -DPOSIX_MISTAKE out.
+# REGCFLAGS isn't important to you (it's for my use in some special contexts).
+CFLAGS=-I. -DPOSIX_MISTAKE -DREDEBUG $(REGCFLAGS)
+
+# If you have a pre-ANSI compiler, put -o into MKHFLAGS.  If you want
+# the Berkeley __P macro, put -b in.
+MKHFLAGS=
+
+# Flags for linking but not compiling, if any.
+LDFLAGS=
+
+# Extra libraries for linking, if any.
+LIBS=
+
+# Internal stuff, should not need changing.
+OBJPRODN=regcomp.o regexec.o regerror.o regfree.o
+OBJS=$(OBJPRODN) split.o debug.o main.o
+H=cclass.h cname.h regex2.h utils.h
+REGSRC=regcomp.c regerror.c regexec.c regfree.c
+ALLSRC=$(REGSRC) engine.c debug.c main.c split.c
+
+# Stuff that matters only if you're trying to lint the package.
+LINTFLAGS=-I. -Dstatic= -Dconst= -DREDEBUG
+LINTC=regcomp.c regexec.c regerror.c regfree.c debug.c main.c
+JUNKLINT=possible pointer alignment|null effect
+
+# arrangements to build forward-reference header files
+.SUFFIXES:	.ih .h
+.c.ih:
+	sh ./mkh $(MKHFLAGS) -p $< >$@
+
+default:	r
+
+lib:	purge $(OBJPRODN)
+	rm -f libregex.a
+	ar crv libregex.a $(OBJPRODN)
+
+purge:
+	rm -f *.o
+
+# stuff to build regex.h
+REGEXH=regex.h
+REGEXHSRC=regex2.h $(REGSRC)
+$(REGEXH):	$(REGEXHSRC) mkh
+	sh ./mkh $(MKHFLAGS) -i _REGEX_H_ $(REGEXHSRC) >regex.tmp
+	cmp -s regex.tmp regex.h 2>/dev/null || cp regex.tmp regex.h
+	rm -f regex.tmp
+
+# dependencies
+$(OBJPRODN) debug.o:	utils.h regex.h regex2.h
+regcomp.o:	cclass.h cname.h regcomp.ih
+regexec.o:	engine.c engine.ih
+regerror.o:	regerror.ih
+debug.o:	debug.ih
+main.o:	main.ih
+
+# tester
+re:	$(OBJS)
+	$(CC) $(CFLAGS) $(LDFLAGS) $(OBJS) $(LIBS) -o $@
+
+# regression test
+r:	re tests
+	./re <tests
+	./re -el <tests
+	./re -er <tests
+
+# 57 variants, and other stuff, for development use -- not useful to you
+ra:	./re tests
+	-./re <tests
+	-./re -el <tests
+	-./re -er <tests
+
+rx:	./re tests
+	./re -x <tests
+	./re -x -el <tests
+	./re -x -er <tests
+
+t:	./re tests
+	-time ./re <tests
+	-time ./re -cs <tests
+	-time ./re -el <tests
+	-time ./re -cs -el <tests
+
+l:	$(LINTC)
+	lint $(LINTFLAGS) -h $(LINTC) 2>&1 | egrep -v '$(JUNKLINT)' | tee lint
+
+fullprint:
+	ti README WHATSNEW notes todo | list
+	ti *.h | list
+	list *.c
+	list regex.3 regex.7
+
+print:
+	ti README WHATSNEW notes todo | list
+	ti *.h | list
+	list reg*.c engine.c
+
+
+mf.tmp:	Makefile
+	sed '/^REGEXH=/s/=.*/=regex.h/' Makefile | sed '/#DEL$$/d' >$@
+
+DTRH=cclass.h cname.h regex2.h utils.h
+PRE=COPYRIGHT README WHATSNEW
+POST=mkh regex.3 regex.7 tests $(DTRH) $(ALLSRC) fake/*.[ch]
+FILES=$(PRE) Makefile $(POST)
+DTR=$(PRE) Makefile=mf.tmp $(POST)
+dtr:	$(FILES) mf.tmp
+	makedtr $(DTR) >$@
+	rm mf.tmp
+
+cio:	$(FILES)
+	cio $(FILES)
+
+rdf:	$(FILES)
+	rcsdiff -c $(FILES) 2>&1 | p
+
+# various forms of cleanup
+tidy:
+	rm -f junk* core core.* *.core dtr *.tmp lint
+
+clean:	tidy
+	rm -f *.o *.s *.ih re libregex.a
+
+# don't do this one unless you know what you're doing
+spotless:	clean
+	rm -f mkh regex.h
diff --git a/regex/README b/regex/README
new file mode 100644
index 0000000..e6ce373
--- /dev/null
+++ b/regex/README
@@ -0,0 +1,32 @@
+alpha3.8 release.
+Tue Aug 10 15:51:48 EDT 1999
+henry@spsystems.net  (formerly henry@zoo.toronto.edu)
+
+See WHATSNEW for change listing.
+
+installation notes:
+--------
+Read the comments at the beginning of Makefile before running.
+
+Utils.h contains some things that just might have to be modified on
+some systems, as well as a nested include (ugh) of <assert.h>.
+
+The "fake" directory contains quick-and-dirty fakes for some header
+files and routines that old systems may not have.  Note also that
+-DUSEBCOPY will make utils.h substitute bcopy() for memmove().
+
+After that, "make r" will build regcomp.o, regexec.o, regfree.o,
+and regerror.o (the actual routines), bundle them together into a test
+program, and run regression tests on them.  No output is good output.
+
+"make lib" builds just the .o files for the actual routines (when
+you're happy with testing and have adjusted CFLAGS for production),
+and puts them together into libregex.a.  You can pick up either the
+library or *.o ("make lib" makes sure there are no other .o files left
+around to confuse things).
+
+Main.c, debug.c, split.c are used for regression testing but are not part
+of the RE routines themselves.
+
+Regex.h goes in /usr/include.  All other .h files are internal only.
+--------
diff --git a/regex/WHATSNEW b/regex/WHATSNEW
new file mode 100644
index 0000000..1295343
--- /dev/null
+++ b/regex/WHATSNEW
@@ -0,0 +1,108 @@
+New in alpha3.8:  Bug fix for signed/unsigned mixup, found and fixed
+by the FreeBSD folks.
+
+New in alpha3.7:  A bit of cleanup aimed at maximizing portability,
+possibly at slight cost in efficiency.  "ul" suffixes and "unsigned long"
+no longer appear, in particular.
+
+New in alpha3.6:  A couple more portability glitches fixed.
+
+New in alpha3.5:  Active development of this code has been stopped --
+I'm working on a complete reimplementation -- but folks have found some
+minor portability glitches and the like, hence this release to fix them.
+One penalty:  slightly reduced compatibility with old compilers, because
+the ANSI C `unsigned long' type and `ul' constant suffix are used in a
+few places (I could avoid this but it would be considerably more work).
+
+New in alpha3.4:  The complex bug alluded to below has been fixed (in a
+slightly kludgey temporary way that may hurt efficiency a bit; this is
+another "get it out the door for 4.4" release).  The tests at the end of
+the tests file have accordingly been uncommented.  The primary sign of
+the bug was that something like a?b matching ab matched b rather than ab.
+(The bug was essentially specific to this exact situation, else it would
+have shown up earlier.)
+
+New in alpha3.3:  The definition of word boundaries has been altered
+slightly, to more closely match the usual programming notion that "_"
+is an alphabetic.  Stuff used for pre-ANSI systems is now in a subdir,
+and the makefile no longer alludes to it in mysterious ways.  The
+makefile has generally been cleaned up some.  Fixes have been made
+(again!) so that the regression test will run without -DREDEBUG, at
+the cost of weaker checking.  A workaround for a bug in some folks'
+<assert.h> has been added.  And some more things have been added to
+tests, including a couple right at the end which are commented out
+because the code currently flunks them (complex bug; fix coming).
+Plus the usual minor cleanup.
+
+New in alpha3.2:  Assorted bits of cleanup and portability improvement
+(the development base is now a BSDI system using GCC instead of an ancient
+Sun system, and the newer compiler exposed some glitches).  Fix for a
+serious bug that affected REs using many [] (including REG_ICASE REs
+because of the way they are implemented), *sometimes*, depending on
+memory-allocation patterns.  The header-file prototypes no longer name
+the parameters, avoiding possible name conflicts.  The possibility that
+some clot has defined CHAR_MIN as (say) `-128' instead of `(-128)' is
+now handled gracefully.  "uchar" is no longer used as an internal type
+name (too many people have the same idea).  Still the same old lousy
+performance, alas.
+
+New in alpha3.1:  Basically nothing, this release is just a bookkeeping
+convenience.  Stay tuned.
+
+New in alpha3.0:  Performance is no better, alas, but some fixes have been
+made and some functionality has been added.  (This is basically the "get
+it out the door in time for 4.4" release.)  One bug fix:  regfree() didn't
+free the main internal structure (how embarrassing).  It is now possible
+to put NULs in either the RE or the target string, using (resp.) a new
+REG_PEND flag and the old REG_STARTEND flag.  The REG_NOSPEC flag to
+regcomp() makes all characters ordinary, so you can match a literal
+string easily (this will become more useful when performance improves!).
+There are now primitives to match beginnings and ends of words, although
+the syntax is disgusting and so is the implementation.  The REG_ATOI
+debugging interface has changed a bit.  And there has been considerable
+internal cleanup of various kinds.
+
+New in alpha2.3:  Split change list out of README, and moved flags notes
+into Makefile.  Macro-ized the name of regex(7) in regex(3), since it has
+to change for 4.4BSD.  Cleanup work in engine.c, and some new regression
+tests to catch tricky cases thereof.
+
+New in alpha2.2:  Out-of-date manpages updated.  Regerror() acquires two
+small extensions -- REG_ITOA and REG_ATOI -- which avoid debugging kludges
+in my own test program and might be useful to others for similar purposes.
+The regression test will now compile (and run) without REDEBUG.  The
+BRE \$ bug is fixed.  Most uses of "uchar" are gone; it's all chars now.
+Char/uchar parameters are now written int/unsigned, to avoid possible
+portability problems with unpromoted parameters.  Some unsigned casts have
+been introduced to minimize portability problems with shifting into sign
+bits.
+
+New in alpha2.1:  Lots of little stuff, cleanup and fixes.  The one big
+thing is that regex.h is now generated, using mkh, rather than being
+supplied in the distribution; due to circularities in dependencies,
+you have to build regex.h explicitly by "make h".  The two known bugs
+have been fixed (and the regression test now checks for them), as has a
+problem with assertions not being suppressed in the absence of REDEBUG.
+No performance work yet.
+
+New in alpha2:  Backslash-anything is an ordinary character, not an
+error (except, of course, for the handful of backslashed metacharacters
+in BREs), which should reduce script breakage.  The regression test
+checks *where* null strings are supposed to match, and has generally
+been tightened up somewhat.  Small bug fixes in parameter passing (not
+harmful, but technically errors) and some other areas.  Debugging
+invoked by defining REDEBUG rather than not defining NDEBUG.
+
+New in alpha+3:  full prototyping for internal routines, using a little
+helper program, mkh, which extracts prototypes given in stylized comments.
+More minor cleanup.  Buglet fix:  it's CHAR_BIT, not CHAR_BITS.  Simple
+pre-screening of input when a literal string is known to be part of the
+RE; this does wonders for performance.
+
+New in alpha+2:  minor bits of cleanup.  Notably, the number "32" for the
+word width isn't hardwired into regexec.c any more, the public header
+file prototypes the functions if __STDC__ is defined, and some small typos
+in the manpages have been fixed.
+
+New in alpha+1:  improvements to the manual pages, and an important
+extension, the REG_STARTEND option to regexec().
diff --git a/regex/cclass.h b/regex/cclass.h
new file mode 100644
index 0000000..d892103
--- /dev/null
+++ b/regex/cclass.h
@@ -0,0 +1,27 @@
+/* character-class table */
+static struct cclass {
+	char *name;
+	char *chars;
+	char *multis;
+} cclasses[] = {
+	{"alnum",	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",				""},
+	{"alpha",	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
+					""},
+	{"blank",	" \t",		""},
+	{"cntrl",	"\007\b\t\n\v\f\r\1\2\3\4\5\6\16\17\20\21\22\23\24\25\26\27\30\31\32\33\34\35\36\37\177",	""},
+	{"digit",	"0123456789",	""},
+	{"graph",	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~",
+					""},
+	{"lower",	"abcdefghijklmnopqrstuvwxyz",
+					""},
+	{"print",	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~ ",
+					""},
+	{"punct",	"!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~",
+					""},
+	{"space",	"\t\n\v\f\r ",	""},
+	{"upper",	"ABCDEFGHIJKLMNOPQRSTUVWXYZ",
+					""},
+	{"xdigit",	"0123456789ABCDEFabcdef",
+					""},
+	{NULL,		0,		""}
+};
diff --git a/regex/cname.h b/regex/cname.h
new file mode 100644
index 0000000..a4af252
--- /dev/null
+++ b/regex/cname.h
@@ -0,0 +1,102 @@
+/* character-name table */
+static struct cname {
+	char *name;
+	char code;
+} cnames[] = {
+	{"NUL",	'\0'},
+	{"SOH",	'\001'},
+	{"STX",	'\002'},
+	{"ETX",	'\003'},
+	{"EOT",	'\004'},
+	{"ENQ",	'\005'},
+	{"ACK",	'\006'},
+	{"BEL",	'\007'},
+	{"alert",	'\007'},
+	{"BS",		'\010'},
+	{"backspace",	'\b'},
+	{"HT",		'\011'},
+	{"tab",		'\t'},
+	{"LF",		'\012'},
+	{"newline",	'\n'},
+	{"VT",		'\013'},
+	{"vertical-tab",	'\v'},
+	{"FF",		'\014'},
+	{"form-feed",	'\f'},
+	{"CR",		'\015'},
+	{"carriage-return",	'\r'},
+	{"SO",	'\016'},
+	{"SI",	'\017'},
+	{"DLE",	'\020'},
+	{"DC1",	'\021'},
+	{"DC2",	'\022'},
+	{"DC3",	'\023'},
+	{"DC4",	'\024'},
+	{"NAK",	'\025'},
+	{"SYN",	'\026'},
+	{"ETB",	'\027'},
+	{"CAN",	'\030'},
+	{"EM",	'\031'},
+	{"SUB",	'\032'},
+	{"ESC",	'\033'},
+	{"IS4",	'\034'},
+	{"FS",	'\034'},
+	{"IS3",	'\035'},
+	{"GS",	'\035'},
+	{"IS2",	'\036'},
+	{"RS",	'\036'},
+	{"IS1",	'\037'},
+	{"US",	'\037'},
+	{"space",		' '},
+	{"exclamation-mark",	'!'},
+	{"quotation-mark",	'"'},
+	{"number-sign",		'#'},
+	{"dollar-sign",		'$'},
+	{"percent-sign",		'%'},
+	{"ampersand",		'&'},
+	{"apostrophe",		'\''},
+	{"left-parenthesis",	'('},
+	{"right-parenthesis",	')'},
+	{"asterisk",	'*'},
+	{"plus-sign",	'+'},
+	{"comma",	','},
+	{"hyphen",	'-'},
+	{"hyphen-minus",	'-'},
+	{"period",	'.'},
+	{"full-stop",	'.'},
+	{"slash",	'/'},
+	{"solidus",	'/'},
+	{"zero",		'0'},
+	{"one",		'1'},
+	{"two",		'2'},
+	{"three",	'3'},
+	{"four",		'4'},
+	{"five",		'5'},
+	{"six",		'6'},
+	{"seven",	'7'},
+	{"eight",	'8'},
+	{"nine",		'9'},
+	{"colon",	':'},
+	{"semicolon",	';'},
+	{"less-than-sign",	'<'},
+	{"equals-sign",		'='},
+	{"greater-than-sign",	'>'},
+	{"question-mark",	'?'},
+	{"commercial-at",	'@'},
+	{"left-square-bracket",	'['},
+	{"backslash",		'\\'},
+	{"reverse-solidus",	'\\'},
+	{"right-square-bracket",	']'},
+	{"circumflex",		'^'},
+	{"circumflex-accent",	'^'},
+	{"underscore",		'_'},
+	{"low-line",		'_'},
+	{"grave-accent",		'`'},
+	{"left-brace",		'{'},
+	{"left-curly-bracket",	'{'},
+	{"vertical-line",	'|'},
+	{"right-brace",		'}'},
+	{"right-curly-bracket",	'}'},
+	{"tilde",		'~'},
+	{"DEL",	'\177'},
+	{NULL,	0}
+};
diff --git a/regex/debug.c b/regex/debug.c
new file mode 100644
index 0000000..99ce7da
--- /dev/null
+++ b/regex/debug.c
@@ -0,0 +1,242 @@
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <regex.h>
+
+#include "utils.h"
+#include "regex2.h"
+#include "debug.ih"
+
+/*
+ - regprint - print a regexp for debugging
+ == void regprint(regex_t *r, FILE *d);
+ */
+void
+regprint(r, d)
+regex_t *r;
+FILE *d;
+{
+	register struct re_guts *g = r->re_g;
+	register int i;
+	register int c;
+	register int last;
+	int nincat[NC];
+
+	fprintf(d, "%ld states, %d categories", (long)g->nstates,
+							g->ncategories);
+	fprintf(d, ", first %ld last %ld", (long)g->firststate,
+						(long)g->laststate);
+	if (g->iflags&USEBOL)
+		fprintf(d, ", USEBOL");
+	if (g->iflags&USEEOL)
+		fprintf(d, ", USEEOL");
+	if (g->iflags&BAD)
+		fprintf(d, ", BAD");
+	if (g->nsub > 0)
+		fprintf(d, ", nsub=%ld", (long)g->nsub);
+	if (g->must != NULL)
+		fprintf(d, ", must(%ld) `%*s'", (long)g->mlen, (int)g->mlen,
+								g->must);
+	if (g->backrefs)
+		fprintf(d, ", backrefs");
+	if (g->nplus > 0)
+		fprintf(d, ", nplus %ld", (long)g->nplus);
+	fprintf(d, "\n");
+	s_print(g, d);
+	for (i = 0; i < g->ncategories; i++) {
+		nincat[i] = 0;
+		for (c = CHAR_MIN; c <= CHAR_MAX; c++)
+			if (g->categories[c] == i)
+				nincat[i]++;
+	}
+	fprintf(d, "cc0#%d", nincat[0]);
+	for (i = 1; i < g->ncategories; i++)
+		if (nincat[i] == 1) {
+			for (c = CHAR_MIN; c <= CHAR_MAX; c++)
+				if (g->categories[c] == i)
+					break;
+			fprintf(d, ", %d=%s", i, regchar(c));
+		}
+	fprintf(d, "\n");
+	for (i = 1; i < g->ncategories; i++)
+		if (nincat[i] != 1) {
+			fprintf(d, "cc%d\t", i);
+			last = -1;
+			for (c = CHAR_MIN; c <= CHAR_MAX+1; c++)	/* +1 does flush */
+				if (c <= CHAR_MAX && g->categories[c] == i) {
+					if (last < 0) {
+						fprintf(d, "%s", regchar(c));
+						last = c;
+					}
+				} else {
+					if (last >= 0) {
+						if (last != c-1)
+							fprintf(d, "-%s",
+								regchar(c-1));
+						last = -1;
+					}
+				}
+			fprintf(d, "\n");
+		}
+}
+
+/*
+ - s_print - print the strip for debugging
+ == static void s_print(register struct re_guts *g, FILE *d);
+ */
+static void
+s_print(g, d)
+register struct re_guts *g;
+FILE *d;
+{
+	register sop *s;
+	register cset *cs;
+	register int i;
+	register int done = 0;
+	register sop opnd;
+	register int col = 0;
+	register int last;
+	register sopno offset = 2;
+#	define	GAP()	{	if (offset % 5 == 0) { \
+					if (col > 40) { \
+						fprintf(d, "\n\t"); \
+						col = 0; \
+					} else { \
+						fprintf(d, " "); \
+						col++; \
+					} \
+				} else \
+					col++; \
+				offset++; \
+			}
+
+	if (OP(g->strip[0]) != OEND)
+		fprintf(d, "missing initial OEND!\n");
+	for (s = &g->strip[1]; !done; s++) {
+		opnd = OPND(*s);
+		switch (OP(*s)) {
+		case OEND:
+			fprintf(d, "\n");
+			done = 1;
+			break;
+		case OCHAR:
+			if (strchr("\\|()^$.[+*?{}!<> ", (char)opnd) != NULL)
+				fprintf(d, "\\%c", (char)opnd);
+			else
+				fprintf(d, "%s", regchar((char)opnd));
+			break;
+		case OBOL:
+			fprintf(d, "^");
+			break;
+		case OEOL:
+			fprintf(d, "$");
+			break;
+		case OBOW:
+			fprintf(d, "\\{");
+			break;
+		case OEOW:
+			fprintf(d, "\\}");
+			break;
+		case OANY:
+			fprintf(d, ".");
+			break;
+		case OANYOF:
+			fprintf(d, "[(%ld)", (long)opnd);
+			cs = &g->sets[opnd];
+			last = -1;
+			for (i = 0; i < g->csetsize+1; i++)	/* +1 flushes */
+				if (CHIN(cs, i) && i < g->csetsize) {
+					if (last < 0) {
+						fprintf(d, "%s", regchar(i));
+						last = i;
+					}
+				} else {
+					if (last >= 0) {
+						if (last != i-1)
+							fprintf(d, "-%s",
+								regchar(i-1));
+						last = -1;
+					}
+				}
+			fprintf(d, "]");
+			break;
+		case OBACK_:
+			fprintf(d, "(\\<%ld>", (long)opnd);
+			break;
+		case O_BACK:
+			fprintf(d, "<%ld>\\)", (long)opnd);
+			break;
+		case OPLUS_:
+			fprintf(d, "(+");
+			if (OP(*(s+opnd)) != O_PLUS)
+				fprintf(d, "<%ld>", (long)opnd);
+			break;
+		case O_PLUS:
+			if (OP(*(s-opnd)) != OPLUS_)
+				fprintf(d, "<%ld>", (long)opnd);
+			fprintf(d, "+)");
+			break;
+		case OQUEST_:
+			fprintf(d, "(?");
+			if (OP(*(s+opnd)) != O_QUEST)
+				fprintf(d, "<%ld>", (long)opnd);
+			break;
+		case O_QUEST:
+			if (OP(*(s-opnd)) != OQUEST_)
+				fprintf(d, "<%ld>", (long)opnd);
+			fprintf(d, "?)");
+			break;
+		case OLPAREN:
+			fprintf(d, "((<%ld>", (long)opnd);
+			break;
+		case ORPAREN:
+			fprintf(d, "<%ld>))", (long)opnd);
+			break;
+		case OCH_:
+			fprintf(d, "<");
+			if (OP(*(s+opnd)) != OOR2)
+				fprintf(d, "<%ld>", (long)opnd);
+			break;
+		case OOR1:
+			if (OP(*(s-opnd)) != OOR1 && OP(*(s-opnd)) != OCH_)
+				fprintf(d, "<%ld>", (long)opnd);
+			fprintf(d, "|");
+			break;
+		case OOR2:
+			fprintf(d, "|");
+			if (OP(*(s+opnd)) != OOR2 && OP(*(s+opnd)) != O_CH)
+				fprintf(d, "<%ld>", (long)opnd);
+			break;
+		case O_CH:
+			if (OP(*(s-opnd)) != OOR1)
+				fprintf(d, "<%ld>", (long)opnd);
+			fprintf(d, ">");
+			break;
+		default:
+			fprintf(d, "!%d(%d)!", OP(*s), opnd);
+			break;
+		}
+		if (!done)
+			GAP();
+	}
+}
+
+/*
+ - regchar - make a character printable
+ == static char *regchar(int ch);
+ */
+static char *			/* -> representation */
+regchar(ch)
+int ch;
+{
+	static char buf[10];
+
+	if (isprint(ch) || ch == ' ')
+		sprintf(buf, "%c", ch);
+	else
+		sprintf(buf, "\\%o", ch);
+	return(buf);
+}
diff --git a/regex/debug.ih b/regex/debug.ih
new file mode 100644
index 0000000..5f40ff7
--- /dev/null
+++ b/regex/debug.ih
@@ -0,0 +1,14 @@
+/* ========= begin header generated by ./mkh ========= */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* === debug.c === */
+void regprint(regex_t *r, FILE *d);
+static void s_print(register struct re_guts *g, FILE *d);
+static char *regchar(int ch);
+
+#ifdef __cplusplus
+}
+#endif
+/* ========= end header generated by ./mkh ========= */
diff --git a/regex/engine.c b/regex/engine.c
new file mode 100644
index 0000000..919fe3f
--- /dev/null
+++ b/regex/engine.c
@@ -0,0 +1,1019 @@
+/*
+ * The matching engine and friends.  This file is #included by regexec.c
+ * after suitable #defines of a variety of macros used herein, so that
+ * different state representations can be used without duplicating masses
+ * of code.
+ */
+
+#ifdef SNAMES
+#define	matcher	smatcher
+#define	fast	sfast
+#define	slow	sslow
+#define	dissect	sdissect
+#define	backref	sbackref
+#define	step	sstep
+#define	print	sprint
+#define	at	sat
+#define	match	smat
+#endif
+#ifdef LNAMES
+#define	matcher	lmatcher
+#define	fast	lfast
+#define	slow	lslow
+#define	dissect	ldissect
+#define	backref	lbackref
+#define	step	lstep
+#define	print	lprint
+#define	at	lat
+#define	match	lmat
+#endif
+
+/* another structure passed up and down to avoid zillions of parameters */
+struct match {
+	struct re_guts *g;
+	int eflags;
+	regmatch_t *pmatch;	/* [nsub+1] (0 element unused) */
+	char *offp;		/* offsets work from here */
+	char *beginp;		/* start of string -- virtual NUL precedes */
+	char *endp;		/* end of string -- virtual NUL here */
+	char *coldp;		/* can be no match starting before here */
+	char **lastpos;		/* [nplus+1] */
+	STATEVARS;
+	states st;		/* current states */
+	states fresh;		/* states for a fresh start */
+	states tmp;		/* temporary */
+	states empty;		/* empty set of states */
+};
+
+#include "engine.ih"
+
+#ifdef REDEBUG
+#define	SP(t, s, c)	print(m, t, s, c, stdout)
+#define	AT(t, p1, p2, s1, s2)	at(m, t, p1, p2, s1, s2)
+#define	NOTE(str)	{ if (m->eflags&REG_TRACE) printf("=%s\n", (str)); }
+#else
+#define	SP(t, s, c)	/* nothing */
+#define	AT(t, p1, p2, s1, s2)	/* nothing */
+#define	NOTE(s)	/* nothing */
+#endif
+
+/*
+ - matcher - the actual matching engine
+ == static int matcher(register struct re_guts *g, char *string, \
+ ==	size_t nmatch, regmatch_t pmatch[], int eflags);
+ */
+static int			/* 0 success, REG_NOMATCH failure */
+matcher(g, string, nmatch, pmatch, eflags)
+register struct re_guts *g;
+char *string;
+size_t nmatch;
+regmatch_t pmatch[];
+int eflags;
+{
+	register char *endp;
+	register int i;
+	struct match mv;
+	register struct match *m = &mv;
+	register char *dp;
+	const register sopno gf = g->firststate+1;	/* +1 for OEND */
+	const register sopno gl = g->laststate;
+	char *start;
+	char *stop;
+
+	/* simplify the situation where possible */
+	if (g->cflags&REG_NOSUB)
+		nmatch = 0;
+	if (eflags&REG_STARTEND) {
+		start = string + pmatch[0].rm_so;
+		stop = string + pmatch[0].rm_eo;
+	} else {
+		start = string;
+		stop = start + strlen(start);
+	}
+	if (stop < start)
+		return(REG_INVARG);
+
+	/* prescreening; this does wonders for this rather slow code */
+	if (g->must != NULL) {
+		for (dp = start; dp < stop; dp++)
+			if (*dp == g->must[0] && stop - dp >= g->mlen &&
+				memcmp(dp, g->must, (size_t)g->mlen) == 0)
+				break;
+		if (dp == stop)		/* we didn't find g->must */
+			return(REG_NOMATCH);
+	}
+
+	/* match struct setup */
+	m->g = g;
+	m->eflags = eflags;
+	m->pmatch = NULL;
+	m->lastpos = NULL;
+	m->offp = string;
+	m->beginp = start;
+	m->endp = stop;
+	STATESETUP(m, 4);
+	SETUP(m->st);
+	SETUP(m->fresh);
+	SETUP(m->tmp);
+	SETUP(m->empty);
+	CLEAR(m->empty);
+
+	/* this loop does only one repetition except for backrefs */
+	for (;;) {
+		endp = fast(m, start, stop, gf, gl);
+		if (endp == NULL) {		/* a miss */
+			STATETEARDOWN(m);
+			return(REG_NOMATCH);
+		}
+		if (nmatch == 0 && !g->backrefs)
+			break;		/* no further info needed */
+
+		/* where? */
+		assert(m->coldp != NULL);
+		for (;;) {
+			NOTE("finding start");
+			endp = slow(m, m->coldp, stop, gf, gl);
+			if (endp != NULL)
+				break;
+			assert(m->coldp < m->endp);
+			m->coldp++;
+		}
+		if (nmatch == 1 && !g->backrefs)
+			break;		/* no further info needed */
+
+		/* oh my, he wants the subexpressions... */
+		if (m->pmatch == NULL)
+			m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) *
+							sizeof(regmatch_t));
+		if (m->pmatch == NULL) {
+			STATETEARDOWN(m);
+			return(REG_ESPACE);
+		}
+		for (i = 1; i <= m->g->nsub; i++)
+			m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
+		if (!g->backrefs && !(m->eflags&REG_BACKR)) {
+			NOTE("dissecting");
+			dp = dissect(m, m->coldp, endp, gf, gl);
+		} else {
+			if (g->nplus > 0 && m->lastpos == NULL)
+				m->lastpos = (char **)malloc((g->nplus+1) *
+							sizeof(char *));
+			if (g->nplus > 0 && m->lastpos == NULL) {
+				free(m->pmatch);
+				STATETEARDOWN(m);
+				return(REG_ESPACE);
+			}
+			NOTE("backref dissect");
+			dp = backref(m, m->coldp, endp, gf, gl, (sopno)0);
+		}
+		if (dp != NULL)
+			break;
+
+		/* uh-oh... we couldn't find a subexpression-level match */
+		assert(g->backrefs);	/* must be back references doing it */
+		assert(g->nplus == 0 || m->lastpos != NULL);
+		for (;;) {
+			if (dp != NULL || endp <= m->coldp)
+				break;		/* defeat */
+			NOTE("backoff");
+			endp = slow(m, m->coldp, endp-1, gf, gl);
+			if (endp == NULL)
+				break;		/* defeat */
+			/* try it on a shorter possibility */
+#ifndef NDEBUG
+			for (i = 1; i <= m->g->nsub; i++) {
+				assert(m->pmatch[i].rm_so == -1);
+				assert(m->pmatch[i].rm_eo == -1);
+			}
+#endif
+			NOTE("backoff dissect");
+			dp = backref(m, m->coldp, endp, gf, gl, (sopno)0);
+		}
+		assert(dp == NULL || dp == endp);
+		if (dp != NULL)		/* found a shorter one */
+			break;
+
+		/* despite initial appearances, there is no match here */
+		NOTE("false alarm");
+		start = m->coldp + 1;	/* recycle starting later */
+		assert(start <= stop);
+	}
+
+	/* fill in the details if requested */
+	if (nmatch > 0) {
+		pmatch[0].rm_so = m->coldp - m->offp;
+		pmatch[0].rm_eo = endp - m->offp;
+	}
+	if (nmatch > 1) {
+		assert(m->pmatch != NULL);
+		for (i = 1; i < nmatch; i++)
+			if (i <= m->g->nsub)
+				pmatch[i] = m->pmatch[i];
+			else {
+				pmatch[i].rm_so = -1;
+				pmatch[i].rm_eo = -1;
+			}
+	}
+
+	if (m->pmatch != NULL)
+		free((char *)m->pmatch);
+	if (m->lastpos != NULL)
+		free((char *)m->lastpos);
+	STATETEARDOWN(m);
+	return(0);
+}
+
+/*
+ - dissect - figure out what matched what, no back references
+ == static char *dissect(register struct match *m, char *start, \
+ ==	char *stop, sopno startst, sopno stopst);
+ */
+static char *			/* == stop (success) always */
+dissect(m, start, stop, startst, stopst)
+register struct match *m;
+char *start;
+char *stop;
+sopno startst;
+sopno stopst;
+{
+	register int i;
+	register sopno ss;	/* start sop of current subRE */
+	register sopno es;	/* end sop of current subRE */
+	register char *sp;	/* start of string matched by it */
+	register char *stp;	/* string matched by it cannot pass here */
+	register char *rest;	/* start of rest of string */
+	register char *tail;	/* string unmatched by rest of RE */
+	register sopno ssub;	/* start sop of subsubRE */
+	register sopno esub;	/* end sop of subsubRE */
+	register char *ssp;	/* start of string matched by subsubRE */
+	register char *sep;	/* end of string matched by subsubRE */
+	register char *oldssp;	/* previous ssp */
+	register char *dp;
+
+	AT("diss", start, stop, startst, stopst);
+	sp = start;
+	for (ss = startst; ss < stopst; ss = es) {
+		/* identify end of subRE */
+		es = ss;
+		switch (OP(m->g->strip[es])) {
+		case OPLUS_:
+		case OQUEST_:
+			es += OPND(m->g->strip[es]);
+			break;
+		case OCH_:
+			while (OP(m->g->strip[es]) != O_CH)
+				es += OPND(m->g->strip[es]);
+			break;
+		}
+		es++;
+
+		/* figure out what it matched */
+		switch (OP(m->g->strip[ss])) {
+		case OEND:
+			assert(nope);
+			break;
+		case OCHAR:
+			sp++;
+			break;
+		case OBOL:
+		case OEOL:
+		case OBOW:
+		case OEOW:
+			break;
+		case OANY:
+		case OANYOF:
+			sp++;
+			break;
+		case OBACK_:
+		case O_BACK:
+			assert(nope);
+			break;
+		/* cases where length of match is hard to find */
+		case OQUEST_:
+			stp = stop;
+			for (;;) {
+				/* how long could this one be? */
+				rest = slow(m, sp, stp, ss, es);
+				assert(rest != NULL);	/* it did match */
+				/* could the rest match the rest? */
+				tail = slow(m, rest, stop, es, stopst);
+				if (tail == stop)
+					break;		/* yes! */
+				/* no -- try a shorter match for this one */
+				stp = rest - 1;
+				assert(stp >= sp);	/* it did work */
+			}
+			ssub = ss + 1;
+			esub = es - 1;
+			/* did innards match? */
+			if (slow(m, sp, rest, ssub, esub) != NULL) {
+				dp = dissect(m, sp, rest, ssub, esub);
+				assert(dp == rest);
+			} else		/* no */
+				assert(sp == rest);
+			sp = rest;
+			break;
+		case OPLUS_:
+			stp = stop;
+			for (;;) {
+				/* how long could this one be? */
+				rest = slow(m, sp, stp, ss, es);
+				assert(rest != NULL);	/* it did match */
+				/* could the rest match the rest? */
+				tail = slow(m, rest, stop, es, stopst);
+				if (tail == stop)
+					break;		/* yes! */
+				/* no -- try a shorter match for this one */
+				stp = rest - 1;
+				assert(stp >= sp);	/* it did work */
+			}
+			ssub = ss + 1;
+			esub = es - 1;
+			ssp = sp;
+			oldssp = ssp;
+			for (;;) {	/* find last match of innards */
+				sep = slow(m, ssp, rest, ssub, esub);
+				if (sep == NULL || sep == ssp)
+					break;	/* failed or matched null */
+				oldssp = ssp;	/* on to next try */
+				ssp = sep;
+			}
+			if (sep == NULL) {
+				/* last successful match */
+				sep = ssp;
+				ssp = oldssp;
+			}
+			assert(sep == rest);	/* must exhaust substring */
+			assert(slow(m, ssp, sep, ssub, esub) == rest);
+			dp = dissect(m, ssp, sep, ssub, esub);
+			assert(dp == sep);
+			sp = rest;
+			break;
+		case OCH_:
+			stp = stop;
+			for (;;) {
+				/* how long could this one be? */
+				rest = slow(m, sp, stp, ss, es);
+				assert(rest != NULL);	/* it did match */
+				/* could the rest match the rest? */
+				tail = slow(m, rest, stop, es, stopst);
+				if (tail == stop)
+					break;		/* yes! */
+				/* no -- try a shorter match for this one */
+				stp = rest - 1;
+				assert(stp >= sp);	/* it did work */
+			}
+			ssub = ss + 1;
+			esub = ss + OPND(m->g->strip[ss]) - 1;
+			assert(OP(m->g->strip[esub]) == OOR1);
+			for (;;) {	/* find first matching branch */
+				if (slow(m, sp, rest, ssub, esub) == rest)
+					break;	/* it matched all of it */
+				/* that one missed, try next one */
+				assert(OP(m->g->strip[esub]) == OOR1);
+				esub++;
+				assert(OP(m->g->strip[esub]) == OOR2);
+				ssub = esub + 1;
+				esub += OPND(m->g->strip[esub]);
+				if (OP(m->g->strip[esub]) == OOR2)
+					esub--;
+				else
+					assert(OP(m->g->strip[esub]) == O_CH);
+			}
+			dp = dissect(m, sp, rest, ssub, esub);
+			assert(dp == rest);
+			sp = rest;
+			break;
+		case O_PLUS:
+		case O_QUEST:
+		case OOR1:
+		case OOR2:
+		case O_CH:
+			assert(nope);
+			break;
+		case OLPAREN:
+			i = OPND(m->g->strip[ss]);
+			assert(0 < i && i <= m->g->nsub);
+			m->pmatch[i].rm_so = sp - m->offp;
+			break;
+		case ORPAREN:
+			i = OPND(m->g->strip[ss]);
+			assert(0 < i && i <= m->g->nsub);
+			m->pmatch[i].rm_eo = sp - m->offp;
+			break;
+		default:		/* uh oh */
+			assert(nope);
+			break;
+		}
+	}
+
+	assert(sp == stop);
+	return(sp);
+}
+
+/*
+ - backref - figure out what matched what, figuring in back references
+ == static char *backref(register struct match *m, char *start, \
+ ==	char *stop, sopno startst, sopno stopst, sopno lev);
+ */
+static char *			/* == stop (success) or NULL (failure) */
+backref(m, start, stop, startst, stopst, lev)
+register struct match *m;
+char *start;
+char *stop;
+sopno startst;
+sopno stopst;
+sopno lev;			/* PLUS nesting level */
+{
+	register int i;
+	register sopno ss;	/* start sop of current subRE */
+	register char *sp;	/* start of string matched by it */
+	register sopno ssub;	/* start sop of subsubRE */
+	register sopno esub;	/* end sop of subsubRE */
+	register char *ssp;	/* start of string matched by subsubRE */
+	register char *dp;
+	register size_t len;
+	register int hard;
+	register sop s;
+	register regoff_t offsave;
+	register cset *cs;
+
+	AT("back", start, stop, startst, stopst);
+	sp = start;
+
+	/* get as far as we can with easy stuff */
+	hard = 0;
+	for (ss = startst; !hard && ss < stopst; ss++)
+		switch (OP(s = m->g->strip[ss])) {
+		case OCHAR:
+			if (sp == stop || *sp++ != (char)OPND(s))
+				return(NULL);
+			break;
+		case OANY:
+			if (sp == stop)
+				return(NULL);
+			sp++;
+			break;
+		case OANYOF:
+			cs = &m->g->sets[OPND(s)];
+			if (sp == stop || !CHIN(cs, *sp++))
+				return(NULL);
+			break;
+		case OBOL:
+			if ( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
+					(sp < m->endp && *(sp-1) == '\n' &&
+						(m->g->cflags&REG_NEWLINE)) )
+				{ /* yes */ }
+			else
+				return(NULL);
+			break;
+		case OEOL:
+			if ( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
+					(sp < m->endp && *sp == '\n' &&
+						(m->g->cflags&REG_NEWLINE)) )
+				{ /* yes */ }
+			else
+				return(NULL);
+			break;
+		case OBOW:
+			if (( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
+					(sp < m->endp && *(sp-1) == '\n' &&
+						(m->g->cflags&REG_NEWLINE)) ||
+					(sp > m->beginp &&
+							!ISWORD(*(sp-1))) ) &&
+					(sp < m->endp && ISWORD(*sp)) )
+				{ /* yes */ }
+			else
+				return(NULL);
+			break;
+		case OEOW:
+			if (( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
+					(sp < m->endp && *sp == '\n' &&
+						(m->g->cflags&REG_NEWLINE)) ||
+					(sp < m->endp && !ISWORD(*sp)) ) &&
+					(sp > m->beginp && ISWORD(*(sp-1))) )
+				{ /* yes */ }
+			else
+				return(NULL);
+			break;
+		case O_QUEST:
+			break;
+		case OOR1:	/* matches null but needs to skip */
+			ss++;
+			s = m->g->strip[ss];
+			do {
+				assert(OP(s) == OOR2);
+				ss += OPND(s);
+			} while (OP(s = m->g->strip[ss]) != O_CH);
+			/* note that the ss++ gets us past the O_CH */
+			break;
+		default:	/* have to make a choice */
+			hard = 1;
+			break;
+		}
+	if (!hard) {		/* that was it! */
+		if (sp != stop)
+			return(NULL);
+		return(sp);
+	}
+	ss--;			/* adjust for the for's final increment */
+
+	/* the hard stuff */
+	AT("hard", sp, stop, ss, stopst);
+	s = m->g->strip[ss];
+	switch (OP(s)) {
+	case OBACK_:		/* the vilest depths */
+		i = OPND(s);
+		assert(0 < i && i <= m->g->nsub);
+		if (m->pmatch[i].rm_eo == -1)
+			return(NULL);
+		assert(m->pmatch[i].rm_so != -1);
+		len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so;
+		assert(stop - m->beginp >= len);
+		if (sp > stop - len)
+			return(NULL);	/* not enough left to match */
+		ssp = m->offp + m->pmatch[i].rm_so;
+		if (memcmp(sp, ssp, len) != 0)
+			return(NULL);
+		while (m->g->strip[ss] != SOP(O_BACK, i))
+			ss++;
+		return(backref(m, sp+len, stop, ss+1, stopst, lev));
+		break;
+	case OQUEST_:		/* to null or not */
+		dp = backref(m, sp, stop, ss+1, stopst, lev);
+		if (dp != NULL)
+			return(dp);	/* not */
+		return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev));
+		break;
+	case OPLUS_:
+		assert(m->lastpos != NULL);
+		assert(lev+1 <= m->g->nplus);
+		m->lastpos[lev+1] = sp;
+		return(backref(m, sp, stop, ss+1, stopst, lev+1));
+		break;
+	case O_PLUS:
+		if (sp == m->lastpos[lev])	/* last pass matched null */
+			return(backref(m, sp, stop, ss+1, stopst, lev-1));
+		/* try another pass */
+		m->lastpos[lev] = sp;
+		dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev);
+		if (dp == NULL)
+			return(backref(m, sp, stop, ss+1, stopst, lev-1));
+		else
+			return(dp);
+		break;
+	case OCH_:		/* find the right one, if any */
+		ssub = ss + 1;
+		esub = ss + OPND(s) - 1;
+		assert(OP(m->g->strip[esub]) == OOR1);
+		for (;;) {	/* find first matching branch */
+			dp = backref(m, sp, stop, ssub, esub, lev);
+			if (dp != NULL)
+				return(dp);
+			/* that one missed, try next one */
+			if (OP(m->g->strip[esub]) == O_CH)
+				return(NULL);	/* there is none */
+			esub++;
+			assert(OP(m->g->strip[esub]) == OOR2);
+			ssub = esub + 1;
+			esub += OPND(m->g->strip[esub]);
+			if (OP(m->g->strip[esub]) == OOR2)
+				esub--;
+			else
+				assert(OP(m->g->strip[esub]) == O_CH);
+		}
+		break;
+	case OLPAREN:		/* must undo assignment if rest fails */
+		i = OPND(s);
+		assert(0 < i && i <= m->g->nsub);
+		offsave = m->pmatch[i].rm_so;
+		m->pmatch[i].rm_so = sp - m->offp;
+		dp = backref(m, sp, stop, ss+1, stopst, lev);
+		if (dp != NULL)
+			return(dp);
+		m->pmatch[i].rm_so = offsave;
+		return(NULL);
+		break;
+	case ORPAREN:		/* must undo assignment if rest fails */
+		i = OPND(s);
+		assert(0 < i && i <= m->g->nsub);
+		offsave = m->pmatch[i].rm_eo;
+		m->pmatch[i].rm_eo = sp - m->offp;
+		dp = backref(m, sp, stop, ss+1, stopst, lev);
+		if (dp != NULL)
+			return(dp);
+		m->pmatch[i].rm_eo = offsave;
+		return(NULL);
+		break;
+	default:		/* uh oh */
+		assert(nope);
+		break;
+	}
+
+	/* "can't happen" */
+	assert(nope);
+	/* NOTREACHED */
+	return((char *)NULL);	/* dummy */
+}
+
+/*
+ - fast - step through the string at top speed
+ == static char *fast(register struct match *m, char *start, \
+ ==	char *stop, sopno startst, sopno stopst);
+ */
+static char *			/* where tentative match ended, or NULL */
+fast(m, start, stop, startst, stopst)
+register struct match *m;
+char *start;
+char *stop;
+sopno startst;
+sopno stopst;
+{
+	register states st = m->st;
+	register states fresh = m->fresh;
+	register states tmp = m->tmp;
+	register char *p = start;
+	register int c = (start == m->beginp) ? OUT : *(start-1);
+	register int lastc;	/* previous c */
+	register int flagch;
+	register int i;
+	register char *coldp;	/* last p after which no match was underway */
+
+	CLEAR(st);
+	SET1(st, startst);
+	st = step(m->g, startst, stopst, st, NOTHING, st);
+	ASSIGN(fresh, st);
+	SP("start", st, *p);
+	coldp = NULL;
+	for (;;) {
+		/* next character */
+		lastc = c;
+		c = (p == m->endp) ? OUT : *p;
+		if (EQ(st, fresh))
+			coldp = p;
+
+		/* is there an EOL and/or BOL between lastc and c? */
+		flagch = '\0';
+		i = 0;
+		if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
+				(lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
+			flagch = BOL;
+			i = m->g->nbol;
+		}
+		if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
+				(c == OUT && !(m->eflags&REG_NOTEOL)) ) {
+			flagch = (flagch == BOL) ? BOLEOL : EOL;
+			i += m->g->neol;
+		}
+		if (i != 0) {
+			for (; i > 0; i--)
+				st = step(m->g, startst, stopst, st, flagch, st);
+			SP("boleol", st, c);
+		}
+
+		/* how about a word boundary? */
+		if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
+					(c != OUT && ISWORD(c)) ) {
+			flagch = BOW;
+		}
+		if ( (lastc != OUT && ISWORD(lastc)) &&
+				(flagch == EOL || (c != OUT && !ISWORD(c))) ) {
+			flagch = EOW;
+		}
+		if (flagch == BOW || flagch == EOW) {
+			st = step(m->g, startst, stopst, st, flagch, st);
+			SP("boweow", st, c);
+		}
+
+		/* are we done? */
+		if (ISSET(st, stopst) || p == stop)
+			break;		/* NOTE BREAK OUT */
+
+		/* no, we must deal with this character */
+		ASSIGN(tmp, st);
+		ASSIGN(st, fresh);
+		assert(c != OUT);
+		st = step(m->g, startst, stopst, tmp, c, st);
+		SP("aft", st, c);
+		assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
+		p++;
+	}
+
+	assert(coldp != NULL);
+	m->coldp = coldp;
+	if (ISSET(st, stopst))
+		return(p+1);
+	else
+		return(NULL);
+}
+
+/*
+ - slow - step through the string more deliberately
+ == static char *slow(register struct match *m, char *start, \
+ ==	char *stop, sopno startst, sopno stopst);
+ */
+static char *			/* where it ended */
+slow(m, start, stop, startst, stopst)
+register struct match *m;
+char *start;
+char *stop;
+sopno startst;
+sopno stopst;
+{
+	register states st = m->st;
+	register states empty = m->empty;
+	register states tmp = m->tmp;
+	register char *p = start;
+	register int c = (start == m->beginp) ? OUT : *(start-1);
+	register int lastc;	/* previous c */
+	register int flagch;
+	register int i;
+	register char *matchp;	/* last p at which a match ended */
+
+	AT("slow", start, stop, startst, stopst);
+	CLEAR(st);
+	SET1(st, startst);
+	SP("sstart", st, *p);
+	st = step(m->g, startst, stopst, st, NOTHING, st);
+	matchp = NULL;
+	for (;;) {
+		/* next character */
+		lastc = c;
+		c = (p == m->endp) ? OUT : *p;
+
+		/* is there an EOL and/or BOL between lastc and c? */
+		flagch = '\0';
+		i = 0;
+		if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
+				(lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
+			flagch = BOL;
+			i = m->g->nbol;
+		}
+		if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
+				(c == OUT && !(m->eflags&REG_NOTEOL)) ) {
+			flagch = (flagch == BOL) ? BOLEOL : EOL;
+			i += m->g->neol;
+		}
+		if (i != 0) {
+			for (; i > 0; i--)
+				st = step(m->g, startst, stopst, st, flagch, st);
+			SP("sboleol", st, c);
+		}
+
+		/* how about a word boundary? */
+		if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
+					(c != OUT && ISWORD(c)) ) {
+			flagch = BOW;
+		}
+		if ( (lastc != OUT && ISWORD(lastc)) &&
+				(flagch == EOL || (c != OUT && !ISWORD(c))) ) {
+			flagch = EOW;
+		}
+		if (flagch == BOW || flagch == EOW) {
+			st = step(m->g, startst, stopst, st, flagch, st);
+			SP("sboweow", st, c);
+		}
+
+		/* are we done? */
+		if (ISSET(st, stopst))
+			matchp = p;
+		if (EQ(st, empty) || p == stop)
+			break;		/* NOTE BREAK OUT */
+
+		/* no, we must deal with this character */
+		ASSIGN(tmp, st);
+		ASSIGN(st, empty);
+		assert(c != OUT);
+		st = step(m->g, startst, stopst, tmp, c, st);
+		SP("saft", st, c);
+		assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
+		p++;
+	}
+
+	return(matchp);
+}
+
+
+/*
+ - step - map set of states reachable before char to set reachable after
+ == static states step(register struct re_guts *g, sopno start, sopno stop, \
+ ==	register states bef, int ch, register states aft);
+ == #define	BOL	(OUT+1)
+ == #define	EOL	(BOL+1)
+ == #define	BOLEOL	(BOL+2)
+ == #define	NOTHING	(BOL+3)
+ == #define	BOW	(BOL+4)
+ == #define	EOW	(BOL+5)
+ == #define	CODEMAX	(BOL+5)		// highest code used
+ == #define	NONCHAR(c)	((c) > CHAR_MAX)
+ == #define	NNONCHAR	(CODEMAX-CHAR_MAX)
+ */
+static states
+step(g, start, stop, bef, ch, aft)
+register struct re_guts *g;
+sopno start;			/* start state within strip */
+sopno stop;			/* state after stop state within strip */
+register states bef;		/* states reachable before */
+int ch;				/* character or NONCHAR code */
+register states aft;		/* states already known reachable after */
+{
+	register cset *cs;
+	register sop s;
+	register sopno pc;
+	register onestate here;		/* note, macros know this name */
+	register sopno look;
+	register long i;
+
+	for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
+		s = g->strip[pc];
+		switch (OP(s)) {
+		case OEND:
+			assert(pc == stop-1);
+			break;
+		case OCHAR:
+			/* only characters can match */
+			assert(!NONCHAR(ch) || ch != (char)OPND(s));
+			if (ch == (char)OPND(s))
+				FWD(aft, bef, 1);
+			break;
+		case OBOL:
+			if (ch == BOL || ch == BOLEOL)
+				FWD(aft, bef, 1);
+			break;
+		case OEOL:
+			if (ch == EOL || ch == BOLEOL)
+				FWD(aft, bef, 1);
+			break;
+		case OBOW:
+			if (ch == BOW)
+				FWD(aft, bef, 1);
+			break;
+		case OEOW:
+			if (ch == EOW)
+				FWD(aft, bef, 1);
+			break;
+		case OANY:
+			if (!NONCHAR(ch))
+				FWD(aft, bef, 1);
+			break;
+		case OANYOF:
+			cs = &g->sets[OPND(s)];
+			if (!NONCHAR(ch) && CHIN(cs, ch))
+				FWD(aft, bef, 1);
+			break;
+		case OBACK_:		/* ignored here */
+		case O_BACK:
+			FWD(aft, aft, 1);
+			break;
+		case OPLUS_:		/* forward, this is just an empty */
+			FWD(aft, aft, 1);
+			break;
+		case O_PLUS:		/* both forward and back */
+			FWD(aft, aft, 1);
+			i = ISSETBACK(aft, OPND(s));
+			BACK(aft, aft, OPND(s));
+			if (!i && ISSETBACK(aft, OPND(s))) {
+				/* oho, must reconsider loop body */
+				pc -= OPND(s) + 1;
+				INIT(here, pc);
+			}
+			break;
+		case OQUEST_:		/* two branches, both forward */
+			FWD(aft, aft, 1);
+			FWD(aft, aft, OPND(s));
+			break;
+		case O_QUEST:		/* just an empty */
+			FWD(aft, aft, 1);
+			break;
+		case OLPAREN:		/* not significant here */
+		case ORPAREN:
+			FWD(aft, aft, 1);
+			break;
+		case OCH_:		/* mark the first two branches */
+			FWD(aft, aft, 1);
+			assert(OP(g->strip[pc+OPND(s)]) == OOR2);
+			FWD(aft, aft, OPND(s));
+			break;
+		case OOR1:		/* done a branch, find the O_CH */
+			if (ISSTATEIN(aft, here)) {
+				for (look = 1;
+						OP(s = g->strip[pc+look]) != O_CH;
+						look += OPND(s))
+					assert(OP(s) == OOR2);
+				FWD(aft, aft, look);
+			}
+			break;
+		case OOR2:		/* propagate OCH_'s marking */
+			FWD(aft, aft, 1);
+			if (OP(g->strip[pc+OPND(s)]) != O_CH) {
+				assert(OP(g->strip[pc+OPND(s)]) == OOR2);
+				FWD(aft, aft, OPND(s));
+			}
+			break;
+		case O_CH:		/* just empty */
+			FWD(aft, aft, 1);
+			break;
+		default:		/* ooooops... */
+			assert(nope);
+			break;
+		}
+	}
+
+	return(aft);
+}
+
+#ifdef REDEBUG
+/*
+ - print - print a set of states
+ == #ifdef REDEBUG
+ == static void print(struct match *m, char *caption, states st, \
+ ==	int ch, FILE *d);
+ == #endif
+ */
+static void
+print(m, caption, st, ch, d)
+struct match *m;
+char *caption;
+states st;
+int ch;
+FILE *d;
+{
+	register struct re_guts *g = m->g;
+	register int i;
+	register int first = 1;
+
+	if (!(m->eflags&REG_TRACE))
+		return;
+
+	fprintf(d, "%s", caption);
+	if (ch != '\0')
+		fprintf(d, " %s", pchar(ch));
+	for (i = 0; i < g->nstates; i++)
+		if (ISSET(st, i)) {
+			fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
+			first = 0;
+		}
+	fprintf(d, "\n");
+}
+
+/* 
+ - at - print current situation
+ == #ifdef REDEBUG
+ == static void at(struct match *m, char *title, char *start, char *stop, \
+ ==						sopno startst, sopno stopst);
+ == #endif
+ */
+static void
+at(m, title, start, stop, startst, stopst)
+struct match *m;
+char *title;
+char *start;
+char *stop;
+sopno startst;
+sopno stopst;
+{
+	if (!(m->eflags&REG_TRACE))
+		return;
+
+	printf("%s %s-", title, pchar(*start));
+	printf("%s ", pchar(*stop));
+	printf("%ld-%ld\n", (long)startst, (long)stopst);
+}
+
+#ifndef PCHARDONE
+#define	PCHARDONE	/* never again */
+/*
+ - pchar - make a character printable
+ == #ifdef REDEBUG
+ == static char *pchar(int ch);
+ == #endif
+ *
+ * Is this identical to regchar() over in debug.c?  Well, yes.  But a
+ * duplicate here avoids having a debugging-capable regexec.o tied to
+ * a matching debug.o, and this is convenient.  It all disappears in
+ * the non-debug compilation anyway, so it doesn't matter much.
+ */
+static char *			/* -> representation */
+pchar(ch)
+int ch;
+{
+	static char pbuf[10];
+
+	if (isprint(ch) || ch == ' ')
+		sprintf(pbuf, "%c", ch);
+	else
+		sprintf(pbuf, "\\%o", ch);
+	return(pbuf);
+}
+#endif
+#endif
+
+#undef	matcher
+#undef	fast
+#undef	slow
+#undef	dissect
+#undef	backref
+#undef	step
+#undef	print
+#undef	at
+#undef	match
diff --git a/regex/engine.ih b/regex/engine.ih
new file mode 100644
index 0000000..cc98334
--- /dev/null
+++ b/regex/engine.ih
@@ -0,0 +1,35 @@
+/* ========= begin header generated by ./mkh ========= */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* === engine.c === */
+static int matcher(register struct re_guts *g, char *string, size_t nmatch, regmatch_t pmatch[], int eflags);
+static char *dissect(register struct match *m, char *start, char *stop, sopno startst, sopno stopst);
+static char *backref(register struct match *m, char *start, char *stop, sopno startst, sopno stopst, sopno lev);
+static char *fast(register struct match *m, char *start, char *stop, sopno startst, sopno stopst);
+static char *slow(register struct match *m, char *start, char *stop, sopno startst, sopno stopst);
+static states step(register struct re_guts *g, sopno start, sopno stop, register states bef, int ch, register states aft);
+#define	BOL	(OUT+1)
+#define	EOL	(BOL+1)
+#define	BOLEOL	(BOL+2)
+#define	NOTHING	(BOL+3)
+#define	BOW	(BOL+4)
+#define	EOW	(BOL+5)
+#define	CODEMAX	(BOL+5)		/* highest code used */
+#define	NONCHAR(c)	((c) > CHAR_MAX)
+#define	NNONCHAR	(CODEMAX-CHAR_MAX)
+#ifdef REDEBUG
+static void print(struct match *m, char *caption, states st, int ch, FILE *d);
+#endif
+#ifdef REDEBUG
+static void at(struct match *m, char *title, char *start, char *stop, sopno startst, sopno stopst);
+#endif
+#ifdef REDEBUG
+static char *pchar(int ch);
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+/* ========= end header generated by ./mkh ========= */
diff --git a/regex/main.c b/regex/main.c
new file mode 100644
index 0000000..0221e77
--- /dev/null
+++ b/regex/main.c
@@ -0,0 +1,510 @@
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <regex.h>
+#include <assert.h>
+
+#include "main.ih"
+
+char *progname;
+int debug = 0;
+int line = 0;
+int status = 0;
+
+int copts = REG_EXTENDED;
+int eopts = 0;
+regoff_t startoff = 0;
+regoff_t endoff = 0;
+
+
+extern int split();
+extern void regprint();
+
+/*
+ - main - do the simple case, hand off to regress() for regression
+ */
+main(argc, argv)
+int argc;
+char *argv[];
+{
+	regex_t re;
+#	define	NS	10
+	regmatch_t subs[NS];
+	char erbuf[100];
+	int err;
+	size_t len;
+	int c;
+	int errflg = 0;
+	register int i;
+	extern int optind;
+	extern char *optarg;
+
+	progname = argv[0];
+
+	while ((c = getopt(argc, argv, "c:e:S:E:x")) != EOF)
+		switch (c) {
+		case 'c':	/* compile options */
+			copts = options('c', optarg);
+			break;
+		case 'e':	/* execute options */
+			eopts = options('e', optarg);
+			break;
+		case 'S':	/* start offset */
+			startoff = (regoff_t)atoi(optarg);
+			break;
+		case 'E':	/* end offset */
+			endoff = (regoff_t)atoi(optarg);
+			break;
+		case 'x':	/* Debugging. */
+			debug++;
+			break;
+		case '?':
+		default:
+			errflg++;
+			break;
+		}
+	if (errflg) {
+		fprintf(stderr, "usage: %s ", progname);
+		fprintf(stderr, "[-c copt][-C][-d] [re]\n");
+		exit(2);
+	}
+
+	if (optind >= argc) {
+		regress(stdin);
+		exit(status);
+	}
+
+	err = regcomp(&re, argv[optind++], copts);
+	if (err) {
+		len = regerror(err, &re, erbuf, sizeof(erbuf));
+		fprintf(stderr, "error %s, %d/%d `%s'\n",
+			eprint(err), len, sizeof(erbuf), erbuf);
+		exit(status);
+	}
+	regprint(&re, stdout);	
+
+	if (optind >= argc) {
+		regfree(&re);
+		exit(status);
+	}
+
+	if (eopts&REG_STARTEND) {
+		subs[0].rm_so = startoff;
+		subs[0].rm_eo = strlen(argv[optind]) - endoff;
+	}
+	err = regexec(&re, argv[optind], (size_t)NS, subs, eopts);
+	if (err) {
+		len = regerror(err, &re, erbuf, sizeof(erbuf));
+		fprintf(stderr, "error %s, %d/%d `%s'\n",
+			eprint(err), len, sizeof(erbuf), erbuf);
+		exit(status);
+	}
+	if (!(copts&REG_NOSUB)) {
+		len = (int)(subs[0].rm_eo - subs[0].rm_so);
+		if (subs[0].rm_so != -1) {
+			if (len != 0)
+				printf("match `%.*s'\n", len,
+					argv[optind] + subs[0].rm_so);
+			else
+				printf("match `'@%.1s\n",
+					argv[optind] + subs[0].rm_so);
+		}
+		for (i = 1; i < NS; i++)
+			if (subs[i].rm_so != -1)
+				printf("(%d) `%.*s'\n", i,
+					(int)(subs[i].rm_eo - subs[i].rm_so),
+					argv[optind] + subs[i].rm_so);
+	}
+	exit(status);
+}
+
+/*
+ - regress - main loop of regression test
+ == void regress(FILE *in);
+ */
+void
+regress(in)
+FILE *in;
+{
+	char inbuf[1000];
+#	define	MAXF	10
+	char *f[MAXF];
+	int nf;
+	int i;
+	char erbuf[100];
+	size_t ne;
+	char *badpat = "invalid regular expression";
+#	define	SHORT	10
+	char *bpname = "REG_BADPAT";
+	regex_t re;
+
+	while (fgets(inbuf, sizeof(inbuf), in) != NULL) {
+		line++;
+		if (inbuf[0] == '#' || inbuf[0] == '\n')
+			continue;			/* NOTE CONTINUE */
+		inbuf[strlen(inbuf)-1] = '\0';	/* get rid of stupid \n */
+		if (debug)
+			fprintf(stdout, "%d:\n", line);
+		nf = split(inbuf, f, MAXF, "\t\t");
+		if (nf < 3) {
+			fprintf(stderr, "bad input, line %d\n", line);
+			exit(1);
+		}
+		for (i = 0; i < nf; i++)
+			if (strcmp(f[i], "\"\"") == 0)
+				f[i] = "";
+		if (nf <= 3)
+			f[3] = NULL;
+		if (nf <= 4)
+			f[4] = NULL;
+		try(f[0], f[1], f[2], f[3], f[4], options('c', f[1]));
+		if (opt('&', f[1]))	/* try with either type of RE */
+			try(f[0], f[1], f[2], f[3], f[4],
+					options('c', f[1]) &~ REG_EXTENDED);
+	}
+
+	ne = regerror(REG_BADPAT, (regex_t *)NULL, erbuf, sizeof(erbuf));
+	if (strcmp(erbuf, badpat) != 0 || ne != strlen(badpat)+1) {
+		fprintf(stderr, "end: regerror() test gave `%s' not `%s'\n",
+							erbuf, badpat);
+		status = 1;
+	}
+	ne = regerror(REG_BADPAT, (regex_t *)NULL, erbuf, (size_t)SHORT);
+	if (strncmp(erbuf, badpat, SHORT-1) != 0 || erbuf[SHORT-1] != '\0' ||
+						ne != strlen(badpat)+1) {
+		fprintf(stderr, "end: regerror() short test gave `%s' not `%.*s'\n",
+						erbuf, SHORT-1, badpat);
+		status = 1;
+	}
+	ne = regerror(REG_ITOA|REG_BADPAT, (regex_t *)NULL, erbuf, sizeof(erbuf));
+	if (strcmp(erbuf, bpname) != 0 || ne != strlen(bpname)+1) {
+		fprintf(stderr, "end: regerror() ITOA test gave `%s' not `%s'\n",
+						erbuf, bpname);
+		status = 1;
+	}
+	re.re_endp = bpname;
+	ne = regerror(REG_ATOI, &re, erbuf, sizeof(erbuf));
+	if (atoi(erbuf) != (int)REG_BADPAT) {
+		fprintf(stderr, "end: regerror() ATOI test gave `%s' not `%ld'\n",
+						erbuf, (long)REG_BADPAT);
+		status = 1;
+	} else if (ne != strlen(erbuf)+1) {
+		fprintf(stderr, "end: regerror() ATOI test len(`%s') = %ld\n",
+						erbuf, (long)REG_BADPAT);
+		status = 1;
+	}
+}
+
+/*
+ - try - try it, and report on problems
+ == void try(char *f0, char *f1, char *f2, char *f3, char *f4, int opts);
+ */
+void
+try(f0, f1, f2, f3, f4, opts)
+char *f0;
+char *f1;
+char *f2;
+char *f3;
+char *f4;
+int opts;			/* may not match f1 */
+{
+	regex_t re;
+#	define	NSUBS	10
+	regmatch_t subs[NSUBS];
+#	define	NSHOULD	15
+	char *should[NSHOULD];
+	int nshould;
+	char erbuf[100];
+	int err;
+	int len;
+	char *type = (opts & REG_EXTENDED) ? "ERE" : "BRE";
+	register int i;
+	char *grump;
+	char f0copy[1000];
+	char f2copy[1000];
+
+	strcpy(f0copy, f0);
+	re.re_endp = (opts&REG_PEND) ? f0copy + strlen(f0copy) : NULL;
+	fixstr(f0copy);
+	err = regcomp(&re, f0copy, opts);
+	if (err != 0 && (!opt('C', f1) || err != efind(f2))) {
+		/* unexpected error or wrong error */
+		len = regerror(err, &re, erbuf, sizeof(erbuf));
+		fprintf(stderr, "%d: %s error %s, %d/%d `%s'\n",
+					line, type, eprint(err), len,
+					sizeof(erbuf), erbuf);
+		status = 1;
+	} else if (err == 0 && opt('C', f1)) {
+		/* unexpected success */
+		fprintf(stderr, "%d: %s should have given REG_%s\n",
+						line, type, f2);
+		status = 1;
+		err = 1;	/* so we won't try regexec */
+	}
+
+	if (err != 0) {
+		regfree(&re);
+		return;
+	}
+
+	strcpy(f2copy, f2);
+	fixstr(f2copy);
+
+	if (options('e', f1)&REG_STARTEND) {
+		if (strchr(f2, '(') == NULL || strchr(f2, ')') == NULL)
+			fprintf(stderr, "%d: bad STARTEND syntax\n", line);
+		subs[0].rm_so = strchr(f2, '(') - f2 + 1;
+		subs[0].rm_eo = strchr(f2, ')') - f2;
+	}
+	err = regexec(&re, f2copy, NSUBS, subs, options('e', f1));
+
+	if (err != 0 && (f3 != NULL || err != REG_NOMATCH)) {
+		/* unexpected error or wrong error */
+		len = regerror(err, &re, erbuf, sizeof(erbuf));
+		fprintf(stderr, "%d: %s exec error %s, %d/%d `%s'\n",
+					line, type, eprint(err), len,
+					sizeof(erbuf), erbuf);
+		status = 1;
+	} else if (err != 0) {
+		/* nothing more to check */
+	} else if (f3 == NULL) {
+		/* unexpected success */
+		fprintf(stderr, "%d: %s exec should have failed\n",
+						line, type);
+		status = 1;
+		err = 1;		/* just on principle */
+	} else if (opts&REG_NOSUB) {
+		/* nothing more to check */
+	} else if ((grump = check(f2, subs[0], f3)) != NULL) {
+		fprintf(stderr, "%d: %s %s\n", line, type, grump);
+		status = 1;
+		err = 1;
+	}
+
+	if (err != 0 || f4 == NULL) {
+		regfree(&re);
+		return;
+	}
+
+	for (i = 1; i < NSHOULD; i++)
+		should[i] = NULL;
+	nshould = split(f4, should+1, NSHOULD-1, ",");
+	if (nshould == 0) {
+		nshould = 1;
+		should[1] = "";
+	}
+	for (i = 1; i < NSUBS; i++) {
+		grump = check(f2, subs[i], should[i]);
+		if (grump != NULL) {
+			fprintf(stderr, "%d: %s $%d %s\n", line,
+							type, i, grump);
+			status = 1;
+			err = 1;
+		}
+	}
+
+	regfree(&re);
+}
+
+/*
+ - options - pick options out of a regression-test string
+ == int options(int type, char *s);
+ */
+int
+options(type, s)
+int type;			/* 'c' compile, 'e' exec */
+char *s;
+{
+	register char *p;
+	register int o = (type == 'c') ? copts : eopts;
+	register char *legal = (type == 'c') ? "bisnmp" : "^$#tl";
+
+	for (p = s; *p != '\0'; p++)
+		if (strchr(legal, *p) != NULL)
+			switch (*p) {
+			case 'b':
+				o &= ~REG_EXTENDED;
+				break;
+			case 'i':
+				o |= REG_ICASE;
+				break;
+			case 's':
+				o |= REG_NOSUB;
+				break;
+			case 'n':
+				o |= REG_NEWLINE;
+				break;
+			case 'm':
+				o &= ~REG_EXTENDED;
+				o |= REG_NOSPEC;
+				break;
+			case 'p':
+				o |= REG_PEND;
+				break;
+			case '^':
+				o |= REG_NOTBOL;
+				break;
+			case '$':
+				o |= REG_NOTEOL;
+				break;
+			case '#':
+				o |= REG_STARTEND;
+				break;
+			case 't':	/* trace */
+				o |= REG_TRACE;
+				break;
+			case 'l':	/* force long representation */
+				o |= REG_LARGE;
+				break;
+			case 'r':	/* force backref use */
+				o |= REG_BACKR;
+				break;
+			}
+	return(o);
+}
+
+/*
+ - opt - is a particular option in a regression string?
+ == int opt(int c, char *s);
+ */
+int				/* predicate */
+opt(c, s)
+int c;
+char *s;
+{
+	return(strchr(s, c) != NULL);
+}
+
+/*
+ - fixstr - transform magic characters in strings
+ == void fixstr(register char *p);
+ */
+void
+fixstr(p)
+register char *p;
+{
+	if (p == NULL)
+		return;
+
+	for (; *p != '\0'; p++)
+		if (*p == 'N')
+			*p = '\n';
+		else if (*p == 'T')
+			*p = '\t';
+		else if (*p == 'S')
+			*p = ' ';
+		else if (*p == 'Z')
+			*p = '\0';
+}
+
+/*
+ - check - check a substring match
+ == char *check(char *str, regmatch_t sub, char *should);
+ */
+char *				/* NULL or complaint */
+check(str, sub, should)
+char *str;
+regmatch_t sub;
+char *should;
+{
+	register int len;
+	register int shlen;
+	register char *p;
+	static char grump[500];
+	register char *at = NULL;
+
+	if (should != NULL && strcmp(should, "-") == 0)
+		should = NULL;
+	if (should != NULL && should[0] == '@') {
+		at = should + 1;
+		should = "";
+	}
+
+	/* check rm_so and rm_eo for consistency */
+	if (sub.rm_so > sub.rm_eo || (sub.rm_so == -1 && sub.rm_eo != -1) ||
+				(sub.rm_so != -1 && sub.rm_eo == -1) ||
+				(sub.rm_so != -1 && sub.rm_so < 0) ||
+				(sub.rm_eo != -1 && sub.rm_eo < 0) ) {
+		sprintf(grump, "start %ld end %ld", (long)sub.rm_so,
+							(long)sub.rm_eo);
+		return(grump);
+	}
+
+	/* check for no match */
+	if (sub.rm_so == -1 && should == NULL)
+		return(NULL);
+	if (sub.rm_so == -1)
+		return("did not match");
+
+	/* check for in range */
+	if (sub.rm_eo > strlen(str)) {
+		sprintf(grump, "start %ld end %ld, past end of string",
+					(long)sub.rm_so, (long)sub.rm_eo);
+		return(grump);
+	}
+
+	len = (int)(sub.rm_eo - sub.rm_so);
+	shlen = (int)strlen(should);
+	p = str + sub.rm_so;
+
+	/* check for not supposed to match */
+	if (should == NULL) {
+		sprintf(grump, "matched `%.*s'", len, p);
+		return(grump);
+	}
+
+	/* check for wrong match */
+	if (len != shlen || strncmp(p, should, (size_t)shlen) != 0) {
+		sprintf(grump, "matched `%.*s' instead", len, p);
+		return(grump);
+	}
+	if (shlen > 0)
+		return(NULL);
+
+	/* check null match in right place */
+	if (at == NULL)
+		return(NULL);
+	shlen = strlen(at);
+	if (shlen == 0)
+		shlen = 1;	/* force check for end-of-string */
+	if (strncmp(p, at, shlen) != 0) {
+		sprintf(grump, "matched null at `%.20s'", p);
+		return(grump);
+	}
+	return(NULL);
+}
+
+/*
+ - eprint - convert error number to name
+ == static char *eprint(int err);
+ */
+static char *
+eprint(err)
+int err;
+{
+	static char epbuf[100];
+	size_t len;
+
+	len = regerror(REG_ITOA|err, (regex_t *)NULL, epbuf, sizeof(epbuf));
+	assert(len <= sizeof(epbuf));
+	return(epbuf);
+}
+
+/*
+ - efind - convert error name to number
+ == static int efind(char *name);
+ */
+static int
+efind(name)
+char *name;
+{
+	static char efbuf[100];
+	size_t n;
+	regex_t re;
+
+	sprintf(efbuf, "REG_%s", name);
+	assert(strlen(efbuf) < sizeof(efbuf));
+	re.re_endp = efbuf;
+	(void) regerror(REG_ATOI, &re, efbuf, sizeof(efbuf));
+	return(atoi(efbuf));
+}
diff --git a/regex/main.ih b/regex/main.ih
new file mode 100644
index 0000000..5a0118a
--- /dev/null
+++ b/regex/main.ih
@@ -0,0 +1,19 @@
+/* ========= begin header generated by ./mkh ========= */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* === main.c === */
+void regress(FILE *in);
+void try(char *f0, char *f1, char *f2, char *f3, char *f4, int opts);
+int options(int type, char *s);
+int opt(int c, char *s);
+void fixstr(register char *p);
+char *check(char *str, regmatch_t sub, char *should);
+static char *eprint(int err);
+static int efind(char *name);
+
+#ifdef __cplusplus
+}
+#endif
+/* ========= end header generated by ./mkh ========= */
diff --git a/regex/mkh b/regex/mkh
new file mode 100755
index 0000000..252b246
--- /dev/null
+++ b/regex/mkh
@@ -0,0 +1,76 @@
+#! /bin/sh
+# mkh - pull headers out of C source
+PATH=/bin:/usr/bin ; export PATH
+
+# egrep pattern to pick out marked lines
+egrep='^ =([ 	]|$)'
+
+# Sed program to process marked lines into lines for the header file.
+# The markers have already been removed.  Two things are done here:  removal
+# of backslashed newlines, and some fudging of comments.  The first is done
+# because -o needs to have prototypes on one line to strip them down.
+# Getting comments into the output is tricky; we turn C++-style // comments
+# into /* */ comments, after altering any existing */'s to avoid trouble.
+peel='	/\\$/N
+	/\\\n[ 	]*/s///g
+	/\/\//s;\*/;* /;g
+	/\/\//s;//\(.*\);/*\1 */;'
+
+for a
+do
+	case "$a" in
+	-o)	# old (pre-function-prototype) compiler
+		# add code to comment out argument lists
+		peel="$peel
+			"'/^\([^#\/][^\/]*[a-zA-Z0-9_)]\)(\(.*\))/s;;\1(/*\2*/);'
+		shift
+		;;
+	-b)	# funny Berkeley __P macro
+		peel="$peel
+			"'/^\([^#\/][^\/]*[a-zA-Z0-9_)]\)(\(.*\))/s;;\1 __P((\2));'
+		shift
+		;;
+	-s)	# compiler doesn't like `static foo();'
+		# add code to get rid of the `static'
+		peel="$peel
+			"'/^static[ 	][^\/]*[a-zA-Z0-9_)](.*)/s;static.;;'
+		shift
+		;;
+	-p)	# private declarations
+		egrep='^ ==([ 	]|$)'
+		shift
+		;;
+	-i)	# wrap in #ifndef, argument is name
+		ifndef="$2"
+		shift ; shift
+		;;
+	*)	break
+		;;
+	esac
+done
+
+if test " $ifndef" != " "
+then
+	echo "#ifndef $ifndef"
+	echo "#define	$ifndef	/* never again */"
+fi
+echo "/* ========= begin header generated by $0 ========= */"
+echo '#ifdef __cplusplus'
+echo 'extern "C" {'
+echo '#endif'
+for f
+do
+	echo
+	echo "/* === $f === */"
+	egrep "$egrep" $f | sed 's/^ ==*[ 	]//;s/^ ==*$//' | sed "$peel"
+	echo
+done
+echo '#ifdef __cplusplus'
+echo '}'
+echo '#endif'
+echo "/* ========= end header generated by $0 ========= */"
+if test " $ifndef" != " "
+then
+	echo "#endif"
+fi
+exit 0
diff --git a/regex/regcomp.c b/regex/regcomp.c
new file mode 100644
index 0000000..27c5303
--- /dev/null
+++ b/regex/regcomp.c
@@ -0,0 +1,1603 @@
+#include <sys/types.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <regex.h>
+
+#include "utils.h"
+#include "regex2.h"
+
+#include "cclass.h"
+#include "cname.h"
+
+/*
+ * parse structure, passed up and down to avoid global variables and
+ * other clumsinesses
+ */
+struct parse {
+	char *next;		/* next character in RE */
+	char *end;		/* end of string (-> NUL normally) */
+	int error;		/* has an error been seen? */
+	sop *strip;		/* malloced strip */
+	sopno ssize;		/* malloced strip size (allocated) */
+	sopno slen;		/* malloced strip length (used) */
+	int ncsalloc;		/* number of csets allocated */
+	struct re_guts *g;
+#	define	NPAREN	10	/* we need to remember () 1-9 for back refs */
+	sopno pbegin[NPAREN];	/* -> ( ([0] unused) */
+	sopno pend[NPAREN];	/* -> ) ([0] unused) */
+};
+
+#include "regcomp.ih"
+
+static char nuls[10];		/* place to point scanner in event of error */
+
+/*
+ * macros for use with parse structure
+ * BEWARE:  these know that the parse structure is named `p' !!!
+ */
+#define	PEEK()	(*p->next)
+#define	PEEK2()	(*(p->next+1))
+#define	MORE()	(p->next < p->end)
+#define	MORE2()	(p->next+1 < p->end)
+#define	SEE(c)	(MORE() && PEEK() == (c))
+#define	SEETWO(a, b)	(MORE() && MORE2() && PEEK() == (a) && PEEK2() == (b))
+#define	EAT(c)	((SEE(c)) ? (NEXT(), 1) : 0)
+#define	EATTWO(a, b)	((SEETWO(a, b)) ? (NEXT2(), 1) : 0)
+#define	NEXT()	(p->next++)
+#define	NEXT2()	(p->next += 2)
+#define	NEXTn(n)	(p->next += (n))
+#define	GETNEXT()	(*p->next++)
+#define	SETERROR(e)	seterr(p, (e))
+#define	REQUIRE(co, e)	((co) || SETERROR(e))
+#define	MUSTSEE(c, e)	(REQUIRE(MORE() && PEEK() == (c), e))
+#define	MUSTEAT(c, e)	(REQUIRE(MORE() && GETNEXT() == (c), e))
+#define	MUSTNOTSEE(c, e)	(REQUIRE(!MORE() || PEEK() != (c), e))
+#define	EMIT(op, sopnd)	doemit(p, (sop)(op), (size_t)(sopnd))
+#define	INSERT(op, pos)	doinsert(p, (sop)(op), HERE()-(pos)+1, pos)
+#define	AHEAD(pos)		dofwd(p, pos, HERE()-(pos))
+#define	ASTERN(sop, pos)	EMIT(sop, HERE()-pos)
+#define	HERE()		(p->slen)
+#define	THERE()		(p->slen - 1)
+#define	THERETHERE()	(p->slen - 2)
+#define	DROP(n)	(p->slen -= (n))
+
+#ifndef NDEBUG
+static int never = 0;		/* for use in asserts; shuts lint up */
+#else
+#define	never	0		/* some <assert.h>s have bugs too */
+#endif
+
+/*
+ - regcomp - interface for parser and compilation
+ = extern int notbuiltin_regcomp(regex_t *, const char *, int);
+ = #define	REG_BASIC	0000
+ = #define	REG_EXTENDED	0001
+ = #define	REG_ICASE	0002
+ = #define	REG_NOSUB	0004
+ = #define	REG_NEWLINE	0010
+ = #define	REG_NOSPEC	0020
+ = #define	REG_PEND	0040
+ = #define	REG_DUMP	0200
+ */
+int				/* 0 success, otherwise REG_something */
+notbuiltin_regcomp(preg, pattern, cflags)
+regex_t *preg;
+const char *pattern;
+int cflags;
+{
+	struct parse pa;
+	register struct re_guts *g;
+	register struct parse *p = &pa;
+	register int i;
+	register size_t len;
+#ifdef REDEBUG
+#	define	GOODFLAGS(f)	(f)
+#else
+#	define	GOODFLAGS(f)	((f)&~REG_DUMP)
+#endif
+
+	cflags = GOODFLAGS(cflags);
+	if ((cflags&REG_EXTENDED) && (cflags&REG_NOSPEC))
+		return(REG_INVARG);
+
+	if (cflags&REG_PEND) {
+		if (preg->re_endp < pattern)
+			return(REG_INVARG);
+		len = preg->re_endp - pattern;
+	} else
+		len = strlen((char *)pattern);
+
+	/* do the mallocs early so failure handling is easy */
+	g = (struct re_guts *)malloc(sizeof(struct re_guts) +
+							(NC-1)*sizeof(cat_t));
+	if (g == NULL)
+		return(REG_ESPACE);
+	p->ssize = len/(size_t)2*(size_t)3 + (size_t)1;	/* ugh */
+	p->strip = (sop *)malloc(p->ssize * sizeof(sop));
+	p->slen = 0;
+	if (p->strip == NULL) {
+		free((char *)g);
+		return(REG_ESPACE);
+	}
+
+	/* set things up */
+	p->g = g;
+	p->next = (char *)pattern;	/* convenience; we do not modify it */
+	p->end = p->next + len;
+	p->error = 0;
+	p->ncsalloc = 0;
+	for (i = 0; i < NPAREN; i++) {
+		p->pbegin[i] = 0;
+		p->pend[i] = 0;
+	}
+	g->csetsize = NC;
+	g->sets = NULL;
+	g->setbits = NULL;
+	g->ncsets = 0;
+	g->cflags = cflags;
+	g->iflags = 0;
+	g->nbol = 0;
+	g->neol = 0;
+	g->must = NULL;
+	g->mlen = 0;
+	g->nsub = 0;
+	g->ncategories = 1;	/* category 0 is "everything else" */
+	g->categories = &g->catspace[-(CHAR_MIN)];
+	(void) memset((char *)g->catspace, 0, NC*sizeof(cat_t));
+	g->backrefs = 0;
+
+	/* do it */
+	EMIT(OEND, 0);
+	g->firststate = THERE();
+	if (cflags&REG_EXTENDED)
+		p_ere(p, OUT);
+	else if (cflags&REG_NOSPEC)
+		p_str(p);
+	else
+		p_bre(p, OUT, OUT);
+	EMIT(OEND, 0);
+	g->laststate = THERE();
+
+	/* tidy up loose ends and fill things in */
+	categorize(p, g);
+	stripsnug(p, g);
+	findmust(p, g);
+	g->nplus = pluscount(p, g);
+	g->magic = MAGIC2;
+	preg->re_nsub = g->nsub;
+	preg->re_g = g;
+	preg->re_magic = MAGIC1;
+#ifndef REDEBUG
+	/* not debugging, so can't rely on the assert() in regexec() */
+	if (g->iflags&BAD)
+		SETERROR(REG_ASSERT);
+#endif
+
+	/* win or lose, we're done */
+	if (p->error != 0)	/* lose */
+		notbuiltin_regfree(preg);
+	return(p->error);
+}
+
+/*
+ - p_ere - ERE parser top level, concatenation and alternation
+ == static void p_ere(register struct parse *p, int stop);
+ */
+static void
+p_ere(p, stop)
+register struct parse *p;
+int stop;			/* character this ERE should end at */
+{
+	register char c;
+	register sopno prevback;
+	register sopno prevfwd;
+	register sopno conc;
+	register int first = 1;		/* is this the first alternative? */
+
+	for (;;) {
+		/* do a bunch of concatenated expressions */
+		conc = HERE();
+		while (MORE() && (c = PEEK()) != '|' && c != stop)
+			p_ere_exp(p);
+		REQUIRE(HERE() != conc, REG_EMPTY);	/* require nonempty */
+
+		if (!EAT('|'))
+			break;		/* NOTE BREAK OUT */
+
+		if (first) {
+			INSERT(OCH_, conc);	/* offset is wrong */
+			prevfwd = conc;
+			prevback = conc;
+			first = 0;
+		}
+		ASTERN(OOR1, prevback);
+		prevback = THERE();
+		AHEAD(prevfwd);			/* fix previous offset */
+		prevfwd = HERE();
+		EMIT(OOR2, 0);			/* offset is very wrong */
+	}
+
+	if (!first) {		/* tail-end fixups */
+		AHEAD(prevfwd);
+		ASTERN(O_CH, prevback);
+	}
+
+	assert(!MORE() || SEE(stop));
+}
+
+/*
+ - p_ere_exp - parse one subERE, an atom possibly followed by a repetition op
+ == static void p_ere_exp(register struct parse *p);
+ */
+static void
+p_ere_exp(p)
+register struct parse *p;
+{
+	register char c;
+	register sopno pos;
+	register int count;
+	register int count2;
+	register sopno subno;
+	int wascaret = 0;
+
+	assert(MORE());		/* caller should have ensured this */
+	c = GETNEXT();
+
+	pos = HERE();
+	switch (c) {
+	case '(':
+		REQUIRE(MORE(), REG_EPAREN);
+		p->g->nsub++;
+		subno = p->g->nsub;
+		if (subno < NPAREN)
+			p->pbegin[subno] = HERE();
+		EMIT(OLPAREN, subno);
+		if (!SEE(')'))
+			p_ere(p, ')');
+		if (subno < NPAREN) {
+			p->pend[subno] = HERE();
+			assert(p->pend[subno] != 0);
+		}
+		EMIT(ORPAREN, subno);
+		MUSTEAT(')', REG_EPAREN);
+		break;
+#ifndef POSIX_MISTAKE
+	case ')':		/* happens only if no current unmatched ( */
+		/*
+		 * You may ask, why the ifndef?  Because I didn't notice
+		 * this until slightly too late for 1003.2, and none of the
+		 * other 1003.2 regular-expression reviewers noticed it at
+		 * all.  So an unmatched ) is legal POSIX, at least until
+		 * we can get it fixed.
+		 */
+		SETERROR(REG_EPAREN);
+		break;
+#endif
+	case '^':
+		EMIT(OBOL, 0);
+		p->g->iflags |= USEBOL;
+		p->g->nbol++;
+		wascaret = 1;
+		break;
+	case '$':
+		EMIT(OEOL, 0);
+		p->g->iflags |= USEEOL;
+		p->g->neol++;
+		break;
+	case '|':
+		SETERROR(REG_EMPTY);
+		break;
+	case '*':
+	case '+':
+	case '?':
+		SETERROR(REG_BADRPT);
+		break;
+	case '.':
+		if (p->g->cflags&REG_NEWLINE)
+			nonnewline(p);
+		else
+			EMIT(OANY, 0);
+		break;
+	case '[':
+		p_bracket(p);
+		break;
+	case '\\':
+		REQUIRE(MORE(), REG_EESCAPE);
+		c = GETNEXT();
+		ordinary(p, c);
+		break;
+	case '{':		/* okay as ordinary except if digit follows */
+		REQUIRE(!MORE() || !isdigit(PEEK()), REG_BADRPT);
+		/* FALLTHROUGH */
+	default:
+		ordinary(p, c);
+		break;
+	}
+
+	if (!MORE())
+		return;
+	c = PEEK();
+	/* we call { a repetition if followed by a digit */
+	if (!( c == '*' || c == '+' || c == '?' ||
+				(c == '{' && MORE2() && isdigit(PEEK2())) ))
+		return;		/* no repetition, we're done */
+	NEXT();
+
+	REQUIRE(!wascaret, REG_BADRPT);
+	switch (c) {
+	case '*':	/* implemented as +? */
+		/* this case does not require the (y|) trick, noKLUDGE */
+		INSERT(OPLUS_, pos);
+		ASTERN(O_PLUS, pos);
+		INSERT(OQUEST_, pos);
+		ASTERN(O_QUEST, pos);
+		break;
+	case '+':
+		INSERT(OPLUS_, pos);
+		ASTERN(O_PLUS, pos);
+		break;
+	case '?':
+		/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
+		INSERT(OCH_, pos);		/* offset slightly wrong */
+		ASTERN(OOR1, pos);		/* this one's right */
+		AHEAD(pos);			/* fix the OCH_ */
+		EMIT(OOR2, 0);			/* offset very wrong... */
+		AHEAD(THERE());			/* ...so fix it */
+		ASTERN(O_CH, THERETHERE());
+		break;
+	case '{':
+		count = p_count(p);
+		if (EAT(',')) {
+			if (isdigit(PEEK())) {
+				count2 = p_count(p);
+				REQUIRE(count <= count2, REG_BADBR);
+			} else		/* single number with comma */
+				count2 = INFINITY;
+		} else		/* just a single number */
+			count2 = count;
+		repeat(p, pos, count, count2);
+		if (!EAT('}')) {	/* error heuristics */
+			while (MORE() && PEEK() != '}')
+				NEXT();
+			REQUIRE(MORE(), REG_EBRACE);
+			SETERROR(REG_BADBR);
+		}
+		break;
+	}
+
+	if (!MORE())
+		return;
+	c = PEEK();
+	if (!( c == '*' || c == '+' || c == '?' ||
+				(c == '{' && MORE2() && isdigit(PEEK2())) ) )
+		return;
+	SETERROR(REG_BADRPT);
+}
+
+/*
+ - p_str - string (no metacharacters) "parser"
+ == static void p_str(register struct parse *p);
+ */
+static void
+p_str(p)
+register struct parse *p;
+{
+	REQUIRE(MORE(), REG_EMPTY);
+	while (MORE())
+		ordinary(p, GETNEXT());
+}
+
+/*
+ - p_bre - BRE parser top level, anchoring and concatenation
+ == static void p_bre(register struct parse *p, register int end1, \
+ ==	register int end2);
+ * Giving end1 as OUT essentially eliminates the end1/end2 check.
+ *
+ * This implementation is a bit of a kludge, in that a trailing $ is first
+ * taken as an ordinary character and then revised to be an anchor.  The
+ * only undesirable side effect is that '$' gets included as a character
+ * category in such cases.  This is fairly harmless; not worth fixing.
+ * The amount of lookahead needed to avoid this kludge is excessive.
+ */
+static void
+p_bre(p, end1, end2)
+register struct parse *p;
+register int end1;		/* first terminating character */
+register int end2;		/* second terminating character */
+{
+	register sopno start = HERE();
+	register int first = 1;			/* first subexpression? */
+	register int wasdollar = 0;
+
+	if (EAT('^')) {
+		EMIT(OBOL, 0);
+		p->g->iflags |= USEBOL;
+		p->g->nbol++;
+	}
+	while (MORE() && !SEETWO(end1, end2)) {
+		wasdollar = p_simp_re(p, first);
+		first = 0;
+	}
+	if (wasdollar) {	/* oops, that was a trailing anchor */
+		DROP(1);
+		EMIT(OEOL, 0);
+		p->g->iflags |= USEEOL;
+		p->g->neol++;
+	}
+
+	REQUIRE(HERE() != start, REG_EMPTY);	/* require nonempty */
+}
+
+/*
+ - p_simp_re - parse a simple RE, an atom possibly followed by a repetition
+ == static int p_simp_re(register struct parse *p, int starordinary);
+ */
+static int			/* was the simple RE an unbackslashed $? */
+p_simp_re(p, starordinary)
+register struct parse *p;
+int starordinary;		/* is a leading * an ordinary character? */
+{
+	register int c;
+	register int count;
+	register int count2;
+	register sopno pos;
+	register int i;
+	register sopno subno;
+#	define	BACKSL	(1<<CHAR_BIT)
+
+	pos = HERE();		/* repetion op, if any, covers from here */
+
+	assert(MORE());		/* caller should have ensured this */
+	c = GETNEXT();
+	if (c == '\\') {
+		REQUIRE(MORE(), REG_EESCAPE);
+		c = BACKSL | (unsigned char)GETNEXT();
+	}
+	switch (c) {
+	case '.':
+		if (p->g->cflags&REG_NEWLINE)
+			nonnewline(p);
+		else
+			EMIT(OANY, 0);
+		break;
+	case '[':
+		p_bracket(p);
+		break;
+	case BACKSL|'{':
+		SETERROR(REG_BADRPT);
+		break;
+	case BACKSL|'(':
+		p->g->nsub++;
+		subno = p->g->nsub;
+		if (subno < NPAREN)
+			p->pbegin[subno] = HERE();
+		EMIT(OLPAREN, subno);
+		/* the MORE here is an error heuristic */
+		if (MORE() && !SEETWO('\\', ')'))
+			p_bre(p, '\\', ')');
+		if (subno < NPAREN) {
+			p->pend[subno] = HERE();
+			assert(p->pend[subno] != 0);
+		}
+		EMIT(ORPAREN, subno);
+		REQUIRE(EATTWO('\\', ')'), REG_EPAREN);
+		break;
+	case BACKSL|')':	/* should not get here -- must be user */
+	case BACKSL|'}':
+		SETERROR(REG_EPAREN);
+		break;
+	case BACKSL|'1':
+	case BACKSL|'2':
+	case BACKSL|'3':
+	case BACKSL|'4':
+	case BACKSL|'5':
+	case BACKSL|'6':
+	case BACKSL|'7':
+	case BACKSL|'8':
+	case BACKSL|'9':
+		i = (c&~BACKSL) - '0';
+		assert(i < NPAREN);
+		if (p->pend[i] != 0) {
+			assert(i <= p->g->nsub);
+			EMIT(OBACK_, i);
+			assert(p->pbegin[i] != 0);
+			assert(OP(p->strip[p->pbegin[i]]) == OLPAREN);
+			assert(OP(p->strip[p->pend[i]]) == ORPAREN);
+			(void) dupl(p, p->pbegin[i]+1, p->pend[i]);
+			EMIT(O_BACK, i);
+		} else
+			SETERROR(REG_ESUBREG);
+		p->g->backrefs = 1;
+		break;
+	case '*':
+		REQUIRE(starordinary, REG_BADRPT);
+		/* FALLTHROUGH */
+	default:
+		ordinary(p, (char)c);	/* takes off BACKSL, if any */
+		break;
+	}
+
+	if (EAT('*')) {		/* implemented as +? */
+		/* this case does not require the (y|) trick, noKLUDGE */
+		INSERT(OPLUS_, pos);
+		ASTERN(O_PLUS, pos);
+		INSERT(OQUEST_, pos);
+		ASTERN(O_QUEST, pos);
+	} else if (EATTWO('\\', '{')) {
+		count = p_count(p);
+		if (EAT(',')) {
+			if (MORE() && isdigit(PEEK())) {
+				count2 = p_count(p);
+				REQUIRE(count <= count2, REG_BADBR);
+			} else		/* single number with comma */
+				count2 = INFINITY;
+		} else		/* just a single number */
+			count2 = count;
+		repeat(p, pos, count, count2);
+		if (!EATTWO('\\', '}')) {	/* error heuristics */
+			while (MORE() && !SEETWO('\\', '}'))
+				NEXT();
+			REQUIRE(MORE(), REG_EBRACE);
+			SETERROR(REG_BADBR);
+		}
+	} else if (c == (unsigned char)'$')	/* $ (but not \$) ends it */
+		return(1);
+
+	return(0);
+}
+
+/*
+ - p_count - parse a repetition count
+ == static int p_count(register struct parse *p);
+ */
+static int			/* the value */
+p_count(p)
+register struct parse *p;
+{
+	register int count = 0;
+	register int ndigits = 0;
+
+	while (MORE() && isdigit(PEEK()) && count <= DUPMAX) {
+		count = count*10 + (GETNEXT() - '0');
+		ndigits++;
+	}
+
+	REQUIRE(ndigits > 0 && count <= DUPMAX, REG_BADBR);
+	return(count);
+}
+
+/*
+ - p_bracket - parse a bracketed character list
+ == static void p_bracket(register struct parse *p);
+ *
+ * Note a significant property of this code:  if the allocset() did SETERROR,
+ * no set operations are done.
+ */
+static void
+p_bracket(p)
+register struct parse *p;
+{
+	register cset *cs = allocset(p);
+	register int invert = 0;
+
+	/* Dept of Truly Sickening Special-Case Kludges */
+	if (p->next + 5 < p->end && strncmp(p->next, "[:<:]]", 6) == 0) {
+		EMIT(OBOW, 0);
+		NEXTn(6);
+		return;
+	}
+	if (p->next + 5 < p->end && strncmp(p->next, "[:>:]]", 6) == 0) {
+		EMIT(OEOW, 0);
+		NEXTn(6);
+		return;
+	}
+
+	if (EAT('^'))
+		invert++;	/* make note to invert set at end */
+	if (EAT(']'))
+		CHadd(cs, ']');
+	else if (EAT('-'))
+		CHadd(cs, '-');
+	while (MORE() && PEEK() != ']' && !SEETWO('-', ']'))
+		p_b_term(p, cs);
+	if (EAT('-'))
+		CHadd(cs, '-');
+	MUSTEAT(']', REG_EBRACK);
+
+	if (p->error != 0)	/* don't mess things up further */
+		return;
+
+	if (p->g->cflags&REG_ICASE) {
+		register int i;
+		register int ci;
+
+		for (i = p->g->csetsize - 1; i >= 0; i--)
+			if (CHIN(cs, i) && isalpha(i)) {
+				ci = othercase(i);
+				if (ci != i)
+					CHadd(cs, ci);
+			}
+		if (cs->multis != NULL)
+			mccase(p, cs);
+	}
+	if (invert) {
+		register int i;
+
+		for (i = p->g->csetsize - 1; i >= 0; i--)
+			if (CHIN(cs, i))
+				CHsub(cs, i);
+			else
+				CHadd(cs, i);
+		if (p->g->cflags&REG_NEWLINE)
+			CHsub(cs, '\n');
+		if (cs->multis != NULL)
+			mcinvert(p, cs);
+	}
+
+	assert(cs->multis == NULL);		/* xxx */
+
+	if (nch(p, cs) == 1) {		/* optimize singleton sets */
+		ordinary(p, firstch(p, cs));
+		freeset(p, cs);
+	} else
+		EMIT(OANYOF, freezeset(p, cs));
+}
+
+/*
+ - p_b_term - parse one term of a bracketed character list
+ == static void p_b_term(register struct parse *p, register cset *cs);
+ */
+static void
+p_b_term(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register char c;
+	register char start, finish;
+	register int i;
+
+	/* classify what we've got */
+	switch ((MORE()) ? PEEK() : '\0') {
+	case '[':
+		c = (MORE2()) ? PEEK2() : '\0';
+		break;
+	case '-':
+		SETERROR(REG_ERANGE);
+		return;			/* NOTE RETURN */
+		break;
+	default:
+		c = '\0';
+		break;
+	}
+
+	switch (c) {
+	case ':':		/* character class */
+		NEXT2();
+		REQUIRE(MORE(), REG_EBRACK);
+		c = PEEK();
+		REQUIRE(c != '-' && c != ']', REG_ECTYPE);
+		p_b_cclass(p, cs);
+		REQUIRE(MORE(), REG_EBRACK);
+		REQUIRE(EATTWO(':', ']'), REG_ECTYPE);
+		break;
+	case '=':		/* equivalence class */
+		NEXT2();
+		REQUIRE(MORE(), REG_EBRACK);
+		c = PEEK();
+		REQUIRE(c != '-' && c != ']', REG_ECOLLATE);
+		p_b_eclass(p, cs);
+		REQUIRE(MORE(), REG_EBRACK);
+		REQUIRE(EATTWO('=', ']'), REG_ECOLLATE);
+		break;
+	default:		/* symbol, ordinary character, or range */
+/* xxx revision needed for multichar stuff */
+		start = p_b_symbol(p);
+		if (SEE('-') && MORE2() && PEEK2() != ']') {
+			/* range */
+			NEXT();
+			if (EAT('-'))
+				finish = '-';
+			else
+				finish = p_b_symbol(p);
+		} else
+			finish = start;
+/* xxx what about signed chars here... */
+		REQUIRE(start <= finish, REG_ERANGE);
+		for (i = start; i <= finish; i++)
+			CHadd(cs, i);
+		break;
+	}
+}
+
+/*
+ - p_b_cclass - parse a character-class name and deal with it
+ == static void p_b_cclass(register struct parse *p, register cset *cs);
+ */
+static void
+p_b_cclass(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register char *sp = p->next;
+	register struct cclass *cp;
+	register size_t len;
+	register char *u;
+	register char c;
+
+	while (MORE() && isalpha(PEEK()))
+		NEXT();
+	len = p->next - sp;
+	for (cp = cclasses; cp->name != NULL; cp++)
+		if (strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0')
+			break;
+	if (cp->name == NULL) {
+		/* oops, didn't find it */
+		SETERROR(REG_ECTYPE);
+		return;
+	}
+
+	u = cp->chars;
+	while ((c = *u++) != '\0')
+		CHadd(cs, c);
+	for (u = cp->multis; *u != '\0'; u += strlen(u) + 1)
+		MCadd(p, cs, u);
+}
+
+/*
+ - p_b_eclass - parse an equivalence-class name and deal with it
+ == static void p_b_eclass(register struct parse *p, register cset *cs);
+ *
+ * This implementation is incomplete. xxx
+ */
+static void
+p_b_eclass(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register char c;
+
+	c = p_b_coll_elem(p, '=');
+	CHadd(cs, c);
+}
+
+/*
+ - p_b_symbol - parse a character or [..]ed multicharacter collating symbol
+ == static char p_b_symbol(register struct parse *p);
+ */
+static char			/* value of symbol */
+p_b_symbol(p)
+register struct parse *p;
+{
+	register char value;
+
+	REQUIRE(MORE(), REG_EBRACK);
+	if (!EATTWO('[', '.'))
+		return(GETNEXT());
+
+	/* collating symbol */
+	value = p_b_coll_elem(p, '.');
+	REQUIRE(EATTWO('.', ']'), REG_ECOLLATE);
+	return(value);
+}
+
+/*
+ - p_b_coll_elem - parse a collating-element name and look it up
+ == static char p_b_coll_elem(register struct parse *p, int endc);
+ */
+static char			/* value of collating element */
+p_b_coll_elem(p, endc)
+register struct parse *p;
+int endc;			/* name ended by endc,']' */
+{
+	register char *sp = p->next;
+	register struct cname *cp;
+	register int len;
+
+	while (MORE() && !SEETWO(endc, ']'))
+		NEXT();
+	if (!MORE()) {
+		SETERROR(REG_EBRACK);
+		return(0);
+	}
+	len = p->next - sp;
+	for (cp = cnames; cp->name != NULL; cp++)
+		if (strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0')
+			return(cp->code);	/* known name */
+	if (len == 1)
+		return(*sp);	/* single character */
+	SETERROR(REG_ECOLLATE);			/* neither */
+	return(0);
+}
+
+/*
+ - othercase - return the case counterpart of an alphabetic
+ == static char othercase(int ch);
+ */
+static char			/* if no counterpart, return ch */
+othercase(ch)
+int ch;
+{
+	assert(isalpha(ch));
+	if (isupper(ch))
+		return(tolower(ch));
+	else if (islower(ch))
+		return(toupper(ch));
+	else			/* peculiar, but could happen */
+		return(ch);
+}
+
+/*
+ - bothcases - emit a dualcase version of a two-case character
+ == static void bothcases(register struct parse *p, int ch);
+ *
+ * Boy, is this implementation ever a kludge...
+ */
+static void
+bothcases(p, ch)
+register struct parse *p;
+int ch;
+{
+	register char *oldnext = p->next;
+	register char *oldend = p->end;
+	char bracket[3];
+
+	assert(othercase(ch) != ch);	/* p_bracket() would recurse */
+	p->next = bracket;
+	p->end = bracket+2;
+	bracket[0] = ch;
+	bracket[1] = ']';
+	bracket[2] = '\0';
+	p_bracket(p);
+	assert(p->next == bracket+2);
+	p->next = oldnext;
+	p->end = oldend;
+}
+
+/*
+ - ordinary - emit an ordinary character
+ == static void ordinary(register struct parse *p, register int ch);
+ */
+static void
+ordinary(p, ch)
+register struct parse *p;
+register int ch;
+{
+	register cat_t *cap = p->g->categories;
+
+	if ((p->g->cflags&REG_ICASE) && isalpha(ch) && othercase(ch) != ch)
+		bothcases(p, ch);
+	else {
+		EMIT(OCHAR, (unsigned char)ch);
+		if (cap[ch] == 0)
+			cap[ch] = p->g->ncategories++;
+	}
+}
+
+/*
+ - nonnewline - emit REG_NEWLINE version of OANY
+ == static void nonnewline(register struct parse *p);
+ *
+ * Boy, is this implementation ever a kludge...
+ */
+static void
+nonnewline(p)
+register struct parse *p;
+{
+	register char *oldnext = p->next;
+	register char *oldend = p->end;
+	char bracket[4];
+
+	p->next = bracket;
+	p->end = bracket+3;
+	bracket[0] = '^';
+	bracket[1] = '\n';
+	bracket[2] = ']';
+	bracket[3] = '\0';
+	p_bracket(p);
+	assert(p->next == bracket+3);
+	p->next = oldnext;
+	p->end = oldend;
+}
+
+/*
+ - repeat - generate code for a bounded repetition, recursively if needed
+ == static void repeat(register struct parse *p, sopno start, int from, int to);
+ */
+static void
+repeat(p, start, from, to)
+register struct parse *p;
+sopno start;			/* operand from here to end of strip */
+int from;			/* repeated from this number */
+int to;				/* to this number of times (maybe INFINITY) */
+{
+	register sopno finish = HERE();
+#	define	N	2
+#	define	INF	3
+#	define	REP(f, t)	((f)*8 + (t))
+#	define	MAP(n)	(((n) <= 1) ? (n) : ((n) == INFINITY) ? INF : N)
+	register sopno copy;
+
+	if (p->error != 0)	/* head off possible runaway recursion */
+		return;
+
+	assert(from <= to);
+
+	switch (REP(MAP(from), MAP(to))) {
+	case REP(0, 0):			/* must be user doing this */
+		DROP(finish-start);	/* drop the operand */
+		break;
+	case REP(0, 1):			/* as x{1,1}? */
+	case REP(0, N):			/* as x{1,n}? */
+	case REP(0, INF):		/* as x{1,}? */
+		/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
+		INSERT(OCH_, start);		/* offset is wrong... */
+		repeat(p, start+1, 1, to);
+		ASTERN(OOR1, start);
+		AHEAD(start);			/* ... fix it */
+		EMIT(OOR2, 0);
+		AHEAD(THERE());
+		ASTERN(O_CH, THERETHERE());
+		break;
+	case REP(1, 1):			/* trivial case */
+		/* done */
+		break;
+	case REP(1, N):			/* as x?x{1,n-1} */
+		/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
+		INSERT(OCH_, start);
+		ASTERN(OOR1, start);
+		AHEAD(start);
+		EMIT(OOR2, 0);			/* offset very wrong... */
+		AHEAD(THERE());			/* ...so fix it */
+		ASTERN(O_CH, THERETHERE());
+		copy = dupl(p, start+1, finish+1);
+		assert(copy == finish+4);
+		repeat(p, copy, 1, to-1);
+		break;
+	case REP(1, INF):		/* as x+ */
+		INSERT(OPLUS_, start);
+		ASTERN(O_PLUS, start);
+		break;
+	case REP(N, N):			/* as xx{m-1,n-1} */
+		copy = dupl(p, start, finish);
+		repeat(p, copy, from-1, to-1);
+		break;
+	case REP(N, INF):		/* as xx{n-1,INF} */
+		copy = dupl(p, start, finish);
+		repeat(p, copy, from-1, to);
+		break;
+	default:			/* "can't happen" */
+		SETERROR(REG_ASSERT);	/* just in case */
+		break;
+	}
+}
+
+/*
+ - seterr - set an error condition
+ == static int seterr(register struct parse *p, int e);
+ */
+static int			/* useless but makes type checking happy */
+seterr(p, e)
+register struct parse *p;
+int e;
+{
+	if (p->error == 0)	/* keep earliest error condition */
+		p->error = e;
+	p->next = nuls;		/* try to bring things to a halt */
+	p->end = nuls;
+	return(0);		/* make the return value well-defined */
+}
+
+/*
+ - allocset - allocate a set of characters for []
+ == static cset *allocset(register struct parse *p);
+ */
+static cset *
+allocset(p)
+register struct parse *p;
+{
+	register int no = p->g->ncsets++;
+	register size_t nc;
+	register size_t nbytes;
+	register cset *cs;
+	register size_t css = (size_t)p->g->csetsize;
+	register int i;
+
+	if (no >= p->ncsalloc) {	/* need another column of space */
+		p->ncsalloc += CHAR_BIT;
+		nc = p->ncsalloc;
+		assert(nc % CHAR_BIT == 0);
+		nbytes = nc / CHAR_BIT * css;
+		if (p->g->sets == NULL)
+			p->g->sets = (cset *)malloc(nc * sizeof(cset));
+		else
+			p->g->sets = (cset *)realloc((char *)p->g->sets,
+							nc * sizeof(cset));
+		if (p->g->setbits == NULL)
+			p->g->setbits = (uch *)malloc(nbytes);
+		else {
+			p->g->setbits = (uch *)realloc((char *)p->g->setbits,
+								nbytes);
+			/* xxx this isn't right if setbits is now NULL */
+			for (i = 0; i < no; i++)
+				p->g->sets[i].ptr = p->g->setbits + css*(i/CHAR_BIT);
+		}
+		if (p->g->sets != NULL && p->g->setbits != NULL)
+			(void) memset((char *)p->g->setbits + (nbytes - css),
+								0, css);
+		else {
+			no = 0;
+			SETERROR(REG_ESPACE);
+			/* caller's responsibility not to do set ops */
+		}
+	}
+
+	assert(p->g->sets != NULL);	/* xxx */
+	cs = &p->g->sets[no];
+	cs->ptr = p->g->setbits + css*((no)/CHAR_BIT);
+	cs->mask = 1 << ((no) % CHAR_BIT);
+	cs->hash = 0;
+	cs->smultis = 0;
+	cs->multis = NULL;
+
+	return(cs);
+}
+
+/*
+ - freeset - free a now-unused set
+ == static void freeset(register struct parse *p, register cset *cs);
+ */
+static void
+freeset(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register int i;
+	register cset *top = &p->g->sets[p->g->ncsets];
+	register size_t css = (size_t)p->g->csetsize;
+
+	for (i = 0; i < css; i++)
+		CHsub(cs, i);
+	if (cs == top-1)	/* recover only the easy case */
+		p->g->ncsets--;
+}
+
+/*
+ - freezeset - final processing on a set of characters
+ == static int freezeset(register struct parse *p, register cset *cs);
+ *
+ * The main task here is merging identical sets.  This is usually a waste
+ * of time (although the hash code minimizes the overhead), but can win
+ * big if REG_ICASE is being used.  REG_ICASE, by the way, is why the hash
+ * is done using addition rather than xor -- all ASCII [aA] sets xor to
+ * the same value!
+ */
+static int			/* set number */
+freezeset(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register uch h = cs->hash;
+	register int i;
+	register cset *top = &p->g->sets[p->g->ncsets];
+	register cset *cs2;
+	register size_t css = (size_t)p->g->csetsize;
+
+	/* look for an earlier one which is the same */
+	for (cs2 = &p->g->sets[0]; cs2 < top; cs2++)
+		if (cs2->hash == h && cs2 != cs) {
+			/* maybe */
+			for (i = 0; i < css; i++)
+				if (!!CHIN(cs2, i) != !!CHIN(cs, i))
+					break;		/* no */
+			if (i == css)
+				break;			/* yes */
+		}
+
+	if (cs2 < top) {	/* found one */
+		freeset(p, cs);
+		cs = cs2;
+	}
+
+	return((int)(cs - p->g->sets));
+}
+
+/*
+ - firstch - return first character in a set (which must have at least one)
+ == static int firstch(register struct parse *p, register cset *cs);
+ */
+static int			/* character; there is no "none" value */
+firstch(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register int i;
+	register size_t css = (size_t)p->g->csetsize;
+
+	for (i = 0; i < css; i++)
+		if (CHIN(cs, i))
+			return((char)i);
+	assert(never);
+	return(0);		/* arbitrary */
+}
+
+/*
+ - nch - number of characters in a set
+ == static int nch(register struct parse *p, register cset *cs);
+ */
+static int
+nch(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register int i;
+	register size_t css = (size_t)p->g->csetsize;
+	register int n = 0;
+
+	for (i = 0; i < css; i++)
+		if (CHIN(cs, i))
+			n++;
+	return(n);
+}
+
+/*
+ - mcadd - add a collating element to a cset
+ == static void mcadd(register struct parse *p, register cset *cs, \
+ ==	register char *cp);
+ */
+static void
+mcadd(p, cs, cp)
+register struct parse *p;
+register cset *cs;
+register char *cp;
+{
+	register size_t oldend = cs->smultis;
+
+	cs->smultis += strlen(cp) + 1;
+	if (cs->multis == NULL)
+		cs->multis = malloc(cs->smultis);
+	else
+		cs->multis = realloc(cs->multis, cs->smultis);
+	if (cs->multis == NULL) {
+		SETERROR(REG_ESPACE);
+		return;
+	}
+
+	(void) strcpy(cs->multis + oldend - 1, cp);
+	cs->multis[cs->smultis - 1] = '\0';
+}
+
+/*
+ - mcsub - subtract a collating element from a cset
+ == static void mcsub(register cset *cs, register char *cp);
+ */
+static void
+mcsub(cs, cp)
+register cset *cs;
+register char *cp;
+{
+	register char *fp = mcfind(cs, cp);
+	register size_t len = strlen(fp);
+
+	assert(fp != NULL);
+	(void) memmove(fp, fp + len + 1,
+				cs->smultis - (fp + len + 1 - cs->multis));
+	cs->smultis -= len;
+
+	if (cs->smultis == 0) {
+		free(cs->multis);
+		cs->multis = NULL;
+		return;
+	}
+
+	cs->multis = realloc(cs->multis, cs->smultis);
+	assert(cs->multis != NULL);
+}
+
+/*
+ - mcin - is a collating element in a cset?
+ == static int mcin(register cset *cs, register char *cp);
+ */
+static int
+mcin(cs, cp)
+register cset *cs;
+register char *cp;
+{
+	return(mcfind(cs, cp) != NULL);
+}
+
+/*
+ - mcfind - find a collating element in a cset
+ == static char *mcfind(register cset *cs, register char *cp);
+ */
+static char *
+mcfind(cs, cp)
+register cset *cs;
+register char *cp;
+{
+	register char *p;
+
+	if (cs->multis == NULL)
+		return(NULL);
+	for (p = cs->multis; *p != '\0'; p += strlen(p) + 1)
+		if (strcmp(cp, p) == 0)
+			return(p);
+	return(NULL);
+}
+
+/*
+ - mcinvert - invert the list of collating elements in a cset
+ == static void mcinvert(register struct parse *p, register cset *cs);
+ *
+ * This would have to know the set of possibilities.  Implementation
+ * is deferred.
+ */
+static void
+mcinvert(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	assert(cs->multis == NULL);	/* xxx */
+}
+
+/*
+ - mccase - add case counterparts of the list of collating elements in a cset
+ == static void mccase(register struct parse *p, register cset *cs);
+ *
+ * This would have to know the set of possibilities.  Implementation
+ * is deferred.
+ */
+static void
+mccase(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	assert(cs->multis == NULL);	/* xxx */
+}
+
+/*
+ - isinsets - is this character in any sets?
+ == static int isinsets(register struct re_guts *g, int c);
+ */
+static int			/* predicate */
+isinsets(g, c)
+register struct re_guts *g;
+int c;
+{
+	register uch *col;
+	register int i;
+	register int ncols = (g->ncsets+(CHAR_BIT-1)) / CHAR_BIT;
+	register unsigned uc = (unsigned char)c;
+
+	for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize)
+		if (col[uc] != 0)
+			return(1);
+	return(0);
+}
+
+/*
+ - samesets - are these two characters in exactly the same sets?
+ == static int samesets(register struct re_guts *g, int c1, int c2);
+ */
+static int			/* predicate */
+samesets(g, c1, c2)
+register struct re_guts *g;
+int c1;
+int c2;
+{
+	register uch *col;
+	register int i;
+	register int ncols = (g->ncsets+(CHAR_BIT-1)) / CHAR_BIT;
+	register unsigned uc1 = (unsigned char)c1;
+	register unsigned uc2 = (unsigned char)c2;
+
+	for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize)
+		if (col[uc1] != col[uc2])
+			return(0);
+	return(1);
+}
+
+/*
+ - categorize - sort out character categories
+ == static void categorize(struct parse *p, register struct re_guts *g);
+ */
+static void
+categorize(p, g)
+struct parse *p;
+register struct re_guts *g;
+{
+	register cat_t *cats = g->categories;
+	register int c;
+	register int c2;
+	register cat_t cat;
+
+	/* avoid making error situations worse */
+	if (p->error != 0)
+		return;
+
+	for (c = CHAR_MIN; c <= CHAR_MAX; c++)
+		if (cats[c] == 0 && isinsets(g, c)) {
+			cat = g->ncategories++;
+			cats[c] = cat;
+			for (c2 = c+1; c2 <= CHAR_MAX; c2++)
+				if (cats[c2] == 0 && samesets(g, c, c2))
+					cats[c2] = cat;
+		}
+}
+
+/*
+ - dupl - emit a duplicate of a bunch of sops
+ == static sopno dupl(register struct parse *p, sopno start, sopno finish);
+ */
+static sopno			/* start of duplicate */
+dupl(p, start, finish)
+register struct parse *p;
+sopno start;			/* from here */
+sopno finish;			/* to this less one */
+{
+	register sopno ret = HERE();
+	register sopno len = finish - start;
+
+	assert(finish >= start);
+	if (len == 0)
+		return(ret);
+	enlarge(p, p->ssize + len);	/* this many unexpected additions */
+	assert(p->ssize >= p->slen + len);
+	(void) memcpy((char *)(p->strip + p->slen),
+		(char *)(p->strip + start), (size_t)len*sizeof(sop));
+	p->slen += len;
+	return(ret);
+}
+
+/*
+ - doemit - emit a strip operator
+ == static void doemit(register struct parse *p, sop op, size_t opnd);
+ *
+ * It might seem better to implement this as a macro with a function as
+ * hard-case backup, but it's just too big and messy unless there are
+ * some changes to the data structures.  Maybe later.
+ */
+static void
+doemit(p, op, opnd)
+register struct parse *p;
+sop op;
+size_t opnd;
+{
+	/* avoid making error situations worse */
+	if (p->error != 0)
+		return;
+
+	/* deal with oversize operands ("can't happen", more or less) */
+	assert(opnd < 1<<OPSHIFT);
+
+	/* deal with undersized strip */
+	if (p->slen >= p->ssize)
+		enlarge(p, (p->ssize+1) / 2 * 3);	/* +50% */
+	assert(p->slen < p->ssize);
+
+	/* finally, it's all reduced to the easy case */
+	p->strip[p->slen++] = SOP(op, opnd);
+}
+
+/*
+ - doinsert - insert a sop into the strip
+ == static void doinsert(register struct parse *p, sop op, size_t opnd, sopno pos);
+ */
+static void
+doinsert(p, op, opnd, pos)
+register struct parse *p;
+sop op;
+size_t opnd;
+sopno pos;
+{
+	register sopno sn;
+	register sop s;
+	register int i;
+
+	/* avoid making error situations worse */
+	if (p->error != 0)
+		return;
+
+	sn = HERE();
+	EMIT(op, opnd);		/* do checks, ensure space */
+	assert(HERE() == sn+1);
+	s = p->strip[sn];
+
+	/* adjust paren pointers */
+	assert(pos > 0);
+	for (i = 1; i < NPAREN; i++) {
+		if (p->pbegin[i] >= pos) {
+			p->pbegin[i]++;
+		}
+		if (p->pend[i] >= pos) {
+			p->pend[i]++;
+		}
+	}
+
+	memmove((char *)&p->strip[pos+1], (char *)&p->strip[pos],
+						(HERE()-pos-1)*sizeof(sop));
+	p->strip[pos] = s;
+}
+
+/*
+ - dofwd - complete a forward reference
+ == static void dofwd(register struct parse *p, sopno pos, sop value);
+ */
+static void
+dofwd(p, pos, value)
+register struct parse *p;
+register sopno pos;
+sop value;
+{
+	/* avoid making error situations worse */
+	if (p->error != 0)
+		return;
+
+	assert(value < 1<<OPSHIFT);
+	p->strip[pos] = OP(p->strip[pos]) | value;
+}
+
+/*
+ - enlarge - enlarge the strip
+ == static void enlarge(register struct parse *p, sopno size);
+ */
+static void
+enlarge(p, size)
+register struct parse *p;
+register sopno size;
+{
+	register sop *sp;
+
+	if (p->ssize >= size)
+		return;
+
+	sp = (sop *)realloc(p->strip, size*sizeof(sop));
+	if (sp == NULL) {
+		SETERROR(REG_ESPACE);
+		return;
+	}
+	p->strip = sp;
+	p->ssize = size;
+}
+
+/*
+ - stripsnug - compact the strip
+ == static void stripsnug(register struct parse *p, register struct re_guts *g);
+ */
+static void
+stripsnug(p, g)
+register struct parse *p;
+register struct re_guts *g;
+{
+	g->nstates = p->slen;
+	g->strip = (sop *)realloc((char *)p->strip, p->slen * sizeof(sop));
+	if (g->strip == NULL) {
+		SETERROR(REG_ESPACE);
+		g->strip = p->strip;
+	}
+}
+
+/*
+ - findmust - fill in must and mlen with longest mandatory literal string
+ == static void findmust(register struct parse *p, register struct re_guts *g);
+ *
+ * This algorithm could do fancy things like analyzing the operands of |
+ * for common subsequences.  Someday.  This code is simple and finds most
+ * of the interesting cases.
+ *
+ * Note that must and mlen got initialized during setup.
+ */
+static void
+findmust(p, g)
+struct parse *p;
+register struct re_guts *g;
+{
+	register sop *scan;
+	sop *start;
+	register sop *newstart;
+	register sopno newlen;
+	register sop s;
+	register char *cp;
+	register sopno i;
+
+	/* avoid making error situations worse */
+	if (p->error != 0)
+		return;
+
+	/* find the longest OCHAR sequence in strip */
+	newlen = 0;
+	scan = g->strip + 1;
+	do {
+		s = *scan++;
+		switch (OP(s)) {
+		case OCHAR:		/* sequence member */
+			if (newlen == 0)		/* new sequence */
+				newstart = scan - 1;
+			newlen++;
+			break;
+		case OPLUS_:		/* things that don't break one */
+		case OLPAREN:
+		case ORPAREN:
+			break;
+		case OQUEST_:		/* things that must be skipped */
+		case OCH_:
+			scan--;
+			do {
+				scan += OPND(s);
+				s = *scan;
+				/* assert() interferes w debug printouts */
+				if (OP(s) != O_QUEST && OP(s) != O_CH &&
+							OP(s) != OOR2) {
+					g->iflags |= BAD;
+					return;
+				}
+			} while (OP(s) != O_QUEST && OP(s) != O_CH);
+			/* fallthrough */
+		default:		/* things that break a sequence */
+			if (newlen > g->mlen) {		/* ends one */
+				start = newstart;
+				g->mlen = newlen;
+			}
+			newlen = 0;
+			break;
+		}
+	} while (OP(s) != OEND);
+
+	if (g->mlen == 0)		/* there isn't one */
+		return;
+
+	/* turn it into a character string */
+	g->must = malloc((size_t)g->mlen + 1);
+	if (g->must == NULL) {		/* argh; just forget it */
+		g->mlen = 0;
+		return;
+	}
+	cp = g->must;
+	scan = start;
+	for (i = g->mlen; i > 0; i--) {
+		while (OP(s = *scan++) != OCHAR)
+			continue;
+		assert(cp < g->must + g->mlen);
+		*cp++ = (char)OPND(s);
+	}
+	assert(cp == g->must + g->mlen);
+	*cp++ = '\0';		/* just on general principles */
+}
+
+/*
+ - pluscount - count + nesting
+ == static sopno pluscount(register struct parse *p, register struct re_guts *g);
+ */
+static sopno			/* nesting depth */
+pluscount(p, g)
+struct parse *p;
+register struct re_guts *g;
+{
+	register sop *scan;
+	register sop s;
+	register sopno plusnest = 0;
+	register sopno maxnest = 0;
+
+	if (p->error != 0)
+		return(0);	/* there may not be an OEND */
+
+	scan = g->strip + 1;
+	do {
+		s = *scan++;
+		switch (OP(s)) {
+		case OPLUS_:
+			plusnest++;
+			break;
+		case O_PLUS:
+			if (plusnest > maxnest)
+				maxnest = plusnest;
+			plusnest--;
+			break;
+		}
+	} while (OP(s) != OEND);
+	if (plusnest != 0)
+		g->iflags |= BAD;
+	return(maxnest);
+}
diff --git a/regex/regcomp.ih b/regex/regcomp.ih
new file mode 100644
index 0000000..0776e71
--- /dev/null
+++ b/regex/regcomp.ih
@@ -0,0 +1,51 @@
+/* ========= begin header generated by ./mkh ========= */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* === regcomp.c === */
+static void p_ere(register struct parse *p, int stop);
+static void p_ere_exp(register struct parse *p);
+static void p_str(register struct parse *p);
+static void p_bre(register struct parse *p, register int end1, register int end2);
+static int p_simp_re(register struct parse *p, int starordinary);
+static int p_count(register struct parse *p);
+static void p_bracket(register struct parse *p);
+static void p_b_term(register struct parse *p, register cset *cs);
+static void p_b_cclass(register struct parse *p, register cset *cs);
+static void p_b_eclass(register struct parse *p, register cset *cs);
+static char p_b_symbol(register struct parse *p);
+static char p_b_coll_elem(register struct parse *p, int endc);
+static char othercase(int ch);
+static void bothcases(register struct parse *p, int ch);
+static void ordinary(register struct parse *p, register int ch);
+static void nonnewline(register struct parse *p);
+static void repeat(register struct parse *p, sopno start, int from, int to);
+static int seterr(register struct parse *p, int e);
+static cset *allocset(register struct parse *p);
+static void freeset(register struct parse *p, register cset *cs);
+static int freezeset(register struct parse *p, register cset *cs);
+static int firstch(register struct parse *p, register cset *cs);
+static int nch(register struct parse *p, register cset *cs);
+static void mcadd(register struct parse *p, register cset *cs, register char *cp);
+static void mcsub(register cset *cs, register char *cp);
+static int mcin(register cset *cs, register char *cp);
+static char *mcfind(register cset *cs, register char *cp);
+static void mcinvert(register struct parse *p, register cset *cs);
+static void mccase(register struct parse *p, register cset *cs);
+static int isinsets(register struct re_guts *g, int c);
+static int samesets(register struct re_guts *g, int c1, int c2);
+static void categorize(struct parse *p, register struct re_guts *g);
+static sopno dupl(register struct parse *p, sopno start, sopno finish);
+static void doemit(register struct parse *p, sop op, size_t opnd);
+static void doinsert(register struct parse *p, sop op, size_t opnd, sopno pos);
+static void dofwd(register struct parse *p, sopno pos, sop value);
+static void enlarge(register struct parse *p, sopno size);
+static void stripsnug(register struct parse *p, register struct re_guts *g);
+static void findmust(register struct parse *p, register struct re_guts *g);
+static sopno pluscount(register struct parse *p, register struct re_guts *g);
+
+#ifdef __cplusplus
+}
+#endif
+/* ========= end header generated by ./mkh ========= */
diff --git a/regex/regerror.c b/regex/regerror.c
new file mode 100644
index 0000000..b9238c8
--- /dev/null
+++ b/regex/regerror.c
@@ -0,0 +1,126 @@
+#include <sys/types.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <regex.h>
+
+#include "utils.h"
+#include "regerror.ih"
+
+/*
+ = #define	REG_OKAY	 0
+ = #define	REG_NOMATCH	 1
+ = #define	REG_BADPAT	 2
+ = #define	REG_ECOLLATE	 3
+ = #define	REG_ECTYPE	 4
+ = #define	REG_EESCAPE	 5
+ = #define	REG_ESUBREG	 6
+ = #define	REG_EBRACK	 7
+ = #define	REG_EPAREN	 8
+ = #define	REG_EBRACE	 9
+ = #define	REG_BADBR	10
+ = #define	REG_ERANGE	11
+ = #define	REG_ESPACE	12
+ = #define	REG_BADRPT	13
+ = #define	REG_EMPTY	14
+ = #define	REG_ASSERT	15
+ = #define	REG_INVARG	16
+ = #define	REG_ATOI	255	// convert name to number (!)
+ = #define	REG_ITOA	0400	// convert number to name (!)
+ */
+static struct rerr {
+	int code;
+	char *name;
+	char *explain;
+} rerrs[] = {
+	{REG_OKAY,	"REG_OKAY",	"no errors detected"},
+	{REG_NOMATCH,	"REG_NOMATCH",	"regexec() failed to match"},
+	{REG_BADPAT,	"REG_BADPAT",	"invalid regular expression"},
+	{REG_ECOLLATE,	"REG_ECOLLATE",	"invalid collating element"},
+	{REG_ECTYPE,	"REG_ECTYPE",	"invalid character class"},
+	{REG_EESCAPE,	"REG_EESCAPE",	"trailing backslash (\\)"},
+	{REG_ESUBREG,	"REG_ESUBREG",	"invalid backreference number"},
+	{REG_EBRACK,	"REG_EBRACK",	"brackets ([ ]) not balanced"},
+	{REG_EPAREN,	"REG_EPAREN",	"parentheses not balanced"},
+	{REG_EBRACE,	"REG_EBRACE",	"braces not balanced"},
+	{REG_BADBR,	"REG_BADBR",	"invalid repetition count(s)"},
+	{REG_ERANGE,	"REG_ERANGE",	"invalid character range"},
+	{REG_ESPACE,	"REG_ESPACE",	"out of memory"},
+	{REG_BADRPT,	"REG_BADRPT",	"repetition-operator operand invalid"},
+	{REG_EMPTY,	"REG_EMPTY",	"empty (sub)expression"},
+	{REG_ASSERT,	"REG_ASSERT",	"\"can't happen\" -- you found a bug"},
+	{REG_INVARG,	"REG_INVARG",	"invalid argument to regex routine"},
+	{-1,		"",		"*** unknown regexp error code ***"}
+};
+
+/*
+ - regerror - the interface to error numbers
+ = extern size_t notbuiltin_regerror(int, const regex_t *, char *, size_t);
+ */
+/* ARGSUSED */
+size_t
+notbuiltin_regerror(errcode, preg, errbuf, errbuf_size)
+int errcode;
+const regex_t *preg;
+char *errbuf;
+size_t errbuf_size;
+{
+	register struct rerr *r;
+	register size_t len;
+	register int target = errcode &~ REG_ITOA;
+	register char *s;
+	char convbuf[50];
+
+	if (errcode == REG_ATOI)
+		s = regatoi(preg, convbuf);
+	else {
+		for (r = rerrs; r->code >= 0; r++)
+			if (r->code == target)
+				break;
+	
+		if (errcode&REG_ITOA) {
+			if (r->code >= 0)
+				(void) strcpy(convbuf, r->name);
+			else
+				sprintf(convbuf, "REG_0x%x", target);
+			assert(strlen(convbuf) < sizeof(convbuf));
+			s = convbuf;
+		} else
+			s = r->explain;
+	}
+
+	len = strlen(s) + 1;
+	if (errbuf_size > 0) {
+		if (errbuf_size > len)
+			(void) strcpy(errbuf, s);
+		else {
+			(void) strncpy(errbuf, s, errbuf_size-1);
+			errbuf[errbuf_size-1] = '\0';
+		}
+	}
+
+	return(len);
+}
+
+/*
+ - regatoi - internal routine to implement REG_ATOI
+ == static char *regatoi(const regex_t *preg, char *localbuf);
+ */
+static char *
+regatoi(preg, localbuf)
+const regex_t *preg;
+char *localbuf;
+{
+	register struct rerr *r;
+
+	for (r = rerrs; r->code >= 0; r++)
+		if (strcmp(r->name, preg->re_endp) == 0)
+			break;
+	if (r->code < 0)
+		return("0");
+
+	sprintf(localbuf, "%d", r->code);
+	return(localbuf);
+}
diff --git a/regex/regerror.ih b/regex/regerror.ih
new file mode 100644
index 0000000..2cb668c
--- /dev/null
+++ b/regex/regerror.ih
@@ -0,0 +1,12 @@
+/* ========= begin header generated by ./mkh ========= */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* === regerror.c === */
+static char *regatoi(const regex_t *preg, char *localbuf);
+
+#ifdef __cplusplus
+}
+#endif
+/* ========= end header generated by ./mkh ========= */
diff --git a/regex/regex.3 b/regex/regex.3
new file mode 100644
index 0000000..bc74709
--- /dev/null
+++ b/regex/regex.3
@@ -0,0 +1,509 @@
+.TH REGEX 3 "25 Sept 1997"
+.BY "Henry Spencer"
+.de ZR
+.\" one other place knows this name:  the SEE ALSO section
+.IR regex (7) \\$1
+..
+.SH NAME
+regcomp, regexec, regerror, regfree \- regular-expression library
+.SH SYNOPSIS
+.ft B
+.\".na
+#include <sys/types.h>
+.br
+#include <regex.h>
+.HP 10
+int regcomp(regex_t\ *preg, const\ char\ *pattern, int\ cflags);
+.HP
+int\ regexec(const\ regex_t\ *preg, const\ char\ *string,
+size_t\ nmatch, regmatch_t\ pmatch[], int\ eflags);
+.HP
+size_t\ regerror(int\ errcode, const\ regex_t\ *preg,
+char\ *errbuf, size_t\ errbuf_size);
+.HP
+void\ regfree(regex_t\ *preg);
+.\".ad
+.ft
+.SH DESCRIPTION
+These routines implement POSIX 1003.2 regular expressions (``RE''s);
+see
+.ZR .
+.I Regcomp
+compiles an RE written as a string into an internal form,
+.I regexec
+matches that internal form against a string and reports results,
+.I regerror
+transforms error codes from either into human-readable messages,
+and
+.I regfree
+frees any dynamically-allocated storage used by the internal form
+of an RE.
+.PP
+The header
+.I <regex.h>
+declares two structure types,
+.I regex_t
+and
+.IR regmatch_t ,
+the former for compiled internal forms and the latter for match reporting.
+It also declares the four functions,
+a type
+.IR regoff_t ,
+and a number of constants with names starting with ``REG_''.
+.PP
+.I Regcomp
+compiles the regular expression contained in the
+.I pattern
+string,
+subject to the flags in
+.IR cflags ,
+and places the results in the
+.I regex_t
+structure pointed to by
+.IR preg .
+.I Cflags
+is the bitwise OR of zero or more of the following flags:
+.IP REG_EXTENDED \w'REG_EXTENDED'u+2n
+Compile modern (``extended'') REs,
+rather than the obsolete (``basic'') REs that
+are the default.
+.IP REG_BASIC
+This is a synonym for 0,
+provided as a counterpart to REG_EXTENDED to improve readability.
+This is an extension,
+compatible with but not specified by POSIX 1003.2,
+and should be used with
+caution in software intended to be portable to other systems.
+.IP REG_NOSPEC
+Compile with recognition of all special characters turned off.
+All characters are thus considered ordinary,
+so the ``RE'' is a literal string.
+This is an extension,
+compatible with but not specified by POSIX 1003.2,
+and should be used with
+caution in software intended to be portable to other systems.
+REG_EXTENDED and REG_NOSPEC may not be used
+in the same call to
+.IR regcomp .
+.IP REG_ICASE
+Compile for matching that ignores upper/lower case distinctions.
+See
+.ZR .
+.IP REG_NOSUB
+Compile for matching that need only report success or failure,
+not what was matched.
+.IP REG_NEWLINE
+Compile for newline-sensitive matching.
+By default, newline is a completely ordinary character with no special
+meaning in either REs or strings.
+With this flag,
+`[^' bracket expressions and `.' never match newline,
+a `^' anchor matches the null string after any newline in the string
+in addition to its normal function,
+and the `$' anchor matches the null string before any newline in the
+string in addition to its normal function.
+.IP REG_PEND
+The regular expression ends,
+not at the first NUL,
+but just before the character pointed to by the
+.I re_endp
+member of the structure pointed to by
+.IR preg .
+The
+.I re_endp
+member is of type
+.IR const\ char\ * .
+This flag permits inclusion of NULs in the RE;
+they are considered ordinary characters.
+This is an extension,
+compatible with but not specified by POSIX 1003.2,
+and should be used with
+caution in software intended to be portable to other systems.
+.PP
+When successful,
+.I regcomp
+returns 0 and fills in the structure pointed to by
+.IR preg .
+One member of that structure
+(other than
+.IR re_endp )
+is publicized:
+.IR re_nsub ,
+of type
+.IR size_t ,
+contains the number of parenthesized subexpressions within the RE
+(except that the value of this member is undefined if the
+REG_NOSUB flag was used).
+If
+.I regcomp
+fails, it returns a non-zero error code;
+see DIAGNOSTICS.
+.PP
+.I Regexec
+matches the compiled RE pointed to by
+.I preg
+against the
+.IR string ,
+subject to the flags in
+.IR eflags ,
+and reports results using
+.IR nmatch ,
+.IR pmatch ,
+and the returned value.
+The RE must have been compiled by a previous invocation of
+.IR regcomp .
+The compiled form is not altered during execution of
+.IR regexec ,
+so a single compiled RE can be used simultaneously by multiple threads.
+.PP
+By default,
+the NUL-terminated string pointed to by
+.I string
+is considered to be the text of an entire line,
+with the NUL indicating the end of the line.
+(That is,
+any other end-of-line marker is considered to have been removed
+and replaced by the NUL.)
+The
+.I eflags
+argument is the bitwise OR of zero or more of the following flags:
+.IP REG_NOTBOL \w'REG_STARTEND'u+2n
+The first character of
+the string
+is not the beginning of a line, so the `^' anchor should not match before it.
+This does not affect the behavior of newlines under REG_NEWLINE.
+.IP REG_NOTEOL
+The NUL terminating
+the string
+does not end a line, so the `$' anchor should not match before it.
+This does not affect the behavior of newlines under REG_NEWLINE.
+.IP REG_STARTEND
+The string is considered to start at
+\fIstring\fR\ + \fIpmatch\fR[0].\fIrm_so\fR
+and to have a terminating NUL located at
+\fIstring\fR\ + \fIpmatch\fR[0].\fIrm_eo\fR
+(there need not actually be a NUL at that location),
+regardless of the value of
+.IR nmatch .
+See below for the definition of
+.IR pmatch
+and
+.IR nmatch .
+This is an extension,
+compatible with but not specified by POSIX 1003.2,
+and should be used with
+caution in software intended to be portable to other systems.
+Note that a non-zero \fIrm_so\fR does not imply REG_NOTBOL;
+REG_STARTEND affects only the location of the string,
+not how it is matched.
+.PP
+See
+.ZR
+for a discussion of what is matched in situations where an RE or a
+portion thereof could match any of several substrings of
+.IR string .
+.PP
+Normally,
+.I regexec
+returns 0 for success and the non-zero code REG_NOMATCH for failure.
+Other non-zero error codes may be returned in exceptional situations;
+see DIAGNOSTICS.
+.PP
+If REG_NOSUB was specified in the compilation of the RE,
+or if
+.I nmatch
+is 0,
+.I regexec
+ignores the
+.I pmatch
+argument (but see below for the case where REG_STARTEND is specified).
+Otherwise,
+.I pmatch
+points to an array of
+.I nmatch
+structures of type
+.IR regmatch_t .
+Such a structure has at least the members
+.I rm_so
+and
+.IR rm_eo ,
+both of type
+.I regoff_t
+(a signed arithmetic type at least as large as an
+.I off_t
+and a
+.IR ssize_t ),
+containing respectively the offset of the first character of a substring
+and the offset of the first character after the end of the substring.
+Offsets are measured from the beginning of the
+.I string
+argument given to
+.IR regexec .
+An empty substring is denoted by equal offsets,
+both indicating the character following the empty substring.
+.PP
+The 0th member of the
+.I pmatch
+array is filled in to indicate what substring of
+.I string
+was matched by the entire RE.
+Remaining members report what substring was matched by parenthesized
+subexpressions within the RE;
+member
+.I i
+reports subexpression
+.IR i ,
+with subexpressions counted (starting at 1) by the order of their opening
+parentheses in the RE, left to right.
+Unused entries in the array\(emcorresponding either to subexpressions that
+did not participate in the match at all, or to subexpressions that do not
+exist in the RE (that is, \fIi\fR\ > \fIpreg\fR\->\fIre_nsub\fR)\(emhave both
+.I rm_so
+and
+.I rm_eo
+set to \-1.
+If a subexpression participated in the match several times,
+the reported substring is the last one it matched.
+(Note, as an example in particular, that when the RE `(b*)+' matches `bbb',
+the parenthesized subexpression matches the three `b's and then
+an infinite number of empty strings following the last `b',
+so the reported substring is one of the empties.)
+.PP
+If REG_STARTEND is specified,
+.I pmatch
+must point to at least one
+.I regmatch_t
+(even if
+.I nmatch
+is 0 or REG_NOSUB was specified),
+to hold the input offsets for REG_STARTEND.
+Use for output is still entirely controlled by
+.IR nmatch ;
+if
+.I nmatch
+is 0 or REG_NOSUB was specified,
+the value of
+.IR pmatch [0]
+will not be changed by a successful
+.IR regexec .
+.PP
+.I Regerror
+maps a non-zero
+.I errcode
+from either
+.I regcomp
+or
+.I regexec
+to a human-readable, printable message.
+If
+.I preg
+is non-NULL,
+the error code should have arisen from use of
+the
+.I regex_t
+pointed to by
+.IR preg ,
+and if the error code came from
+.IR regcomp ,
+it should have been the result from the most recent
+.I regcomp
+using that
+.IR regex_t .
+.RI ( Regerror
+may be able to supply a more detailed message using information
+from the
+.IR regex_t .)
+.I Regerror
+places the NUL-terminated message into the buffer pointed to by
+.IR errbuf ,
+limiting the length (including the NUL) to at most
+.I errbuf_size
+bytes.
+If the whole message won't fit,
+as much of it as will fit before the terminating NUL is supplied.
+In any case,
+the returned value is the size of buffer needed to hold the whole
+message (including terminating NUL).
+If
+.I errbuf_size
+is 0,
+.I errbuf
+is ignored but the return value is still correct.
+.PP
+If the
+.I errcode
+given to
+.I regerror
+is first ORed with REG_ITOA,
+the ``message'' that results is the printable name of the error code,
+e.g. ``REG_NOMATCH'',
+rather than an explanation thereof.
+If
+.I errcode
+is REG_ATOI,
+then
+.I preg
+shall be non-NULL and the
+.I re_endp
+member of the structure it points to
+must point to the printable name of an error code;
+in this case, the result in
+.I errbuf
+is the decimal digits of
+the numeric value of the error code
+(0 if the name is not recognized).
+REG_ITOA and REG_ATOI are intended primarily as debugging facilities;
+they are extensions,
+compatible with but not specified by POSIX 1003.2,
+and should be used with
+caution in software intended to be portable to other systems.
+Be warned also that they are considered experimental and changes are possible.
+.PP
+.I Regfree
+frees any dynamically-allocated storage associated with the compiled RE
+pointed to by
+.IR preg .
+The remaining
+.I regex_t
+is no longer a valid compiled RE
+and the effect of supplying it to
+.I regexec
+or
+.I regerror
+is undefined.
+.PP
+None of these functions references global variables except for tables
+of constants;
+all are safe for use from multiple threads if the arguments are safe.
+.SH IMPLEMENTATION CHOICES
+There are a number of decisions that 1003.2 leaves up to the implementor,
+either by explicitly saying ``undefined'' or by virtue of them being
+forbidden by the RE grammar.
+This implementation treats them as follows.
+.PP
+See
+.ZR
+for a discussion of the definition of case-independent matching.
+.PP
+There is no particular limit on the length of REs,
+except insofar as memory is limited.
+Memory usage is approximately linear in RE size, and largely insensitive
+to RE complexity, except for bounded repetitions.
+See BUGS for one short RE using them
+that will run almost any system out of memory.
+.PP
+A backslashed character other than one specifically given a magic meaning
+by 1003.2 (such magic meanings occur only in obsolete [``basic''] REs)
+is taken as an ordinary character.
+.PP
+Any unmatched [ is a REG_EBRACK error.
+.PP
+Equivalence classes cannot begin or end bracket-expression ranges.
+The endpoint of one range cannot begin another.
+.PP
+RE_DUP_MAX, the limit on repetition counts in bounded repetitions, is 255.
+.PP
+A repetition operator (?, *, +, or bounds) cannot follow another
+repetition operator.
+A repetition operator cannot begin an expression or subexpression
+or follow `^' or `|'.
+.PP
+`|' cannot appear first or last in a (sub)expression or after another `|',
+i.e. an operand of `|' cannot be an empty subexpression.
+An empty parenthesized subexpression, `()', is legal and matches an
+empty (sub)string.
+An empty string is not a legal RE.
+.PP
+A `{' followed by a digit is considered the beginning of bounds for a
+bounded repetition, which must then follow the syntax for bounds.
+A `{' \fInot\fR followed by a digit is considered an ordinary character.
+.PP
+`^' and `$' beginning and ending subexpressions in obsolete (``basic'')
+REs are anchors, not ordinary characters.
+.SH SEE ALSO
+grep(1), regex(7)
+.PP
+POSIX 1003.2, sections 2.8 (Regular Expression Notation)
+and
+B.5 (C Binding for Regular Expression Matching).
+.SH DIAGNOSTICS
+Non-zero error codes from
+.I regcomp
+and
+.I regexec
+include the following:
+.PP
+.nf
+.ta \w'REG_ECOLLATE'u+3n
+REG_NOMATCH	regexec() failed to match
+REG_BADPAT	invalid regular expression
+REG_ECOLLATE	invalid collating element
+REG_ECTYPE	invalid character class
+REG_EESCAPE	\e applied to unescapable character
+REG_ESUBREG	invalid backreference number
+REG_EBRACK	brackets [ ] not balanced
+REG_EPAREN	parentheses ( ) not balanced
+REG_EBRACE	braces { } not balanced
+REG_BADBR	invalid repetition count(s) in { }
+REG_ERANGE	invalid character range in [ ]
+REG_ESPACE	ran out of memory
+REG_BADRPT	?, *, or + operand invalid
+REG_EMPTY	empty (sub)expression
+REG_ASSERT	``can't happen''\(emyou found a bug
+REG_INVARG	invalid argument, e.g. negative-length string
+.fi
+.SH HISTORY
+Written by Henry Spencer,
+henry@zoo.toronto.edu.
+.SH BUGS
+This is an alpha release with known defects.
+Please report problems.
+.PP
+There is one known functionality bug.
+The implementation of internationalization is incomplete:
+the locale is always assumed to be the default one of 1003.2,
+and only the collating elements etc. of that locale are available.
+.PP
+The back-reference code is subtle and doubts linger about its correctness
+in complex cases.
+.PP
+.I Regexec
+performance is poor.
+This will improve with later releases.
+.I Nmatch
+exceeding 0 is expensive;
+.I nmatch
+exceeding 1 is worse.
+.I Regexec
+is largely insensitive to RE complexity \fIexcept\fR that back
+references are massively expensive.
+RE length does matter; in particular, there is a strong speed bonus
+for keeping RE length under about 30 characters,
+with most special characters counting roughly double.
+.PP
+.I Regcomp
+implements bounded repetitions by macro expansion,
+which is costly in time and space if counts are large
+or bounded repetitions are nested.
+An RE like, say,
+`((((a{1,100}){1,100}){1,100}){1,100}){1,100}'
+will (eventually) run almost any existing machine out of swap space.
+.PP
+There are suspected problems with response to obscure error conditions.
+Notably,
+certain kinds of internal overflow,
+produced only by truly enormous REs or by multiply nested bounded repetitions,
+are probably not handled well.
+.PP
+Due to a mistake in 1003.2, things like `a)b' are legal REs because `)' is
+a special character only in the presence of a previous unmatched `('.
+This can't be fixed until the spec is fixed.
+.PP
+The standard's definition of back references is vague.
+For example, does
+`a\e(\e(b\e)*\e2\e)*d' match `abbbd'?
+Until the standard is clarified,
+behavior in such cases should not be relied on.
+.PP
+The implementation of word-boundary matching is a bit of a kludge,
+and bugs may lurk in combinations of word-boundary matching and anchoring.
diff --git a/regex/regex.7 b/regex/regex.7
new file mode 100644
index 0000000..0fa1802
--- /dev/null
+++ b/regex/regex.7
@@ -0,0 +1,235 @@
+.TH REGEX 7 "25 Oct 1995"
+.BY "Henry Spencer"
+.SH NAME
+regex \- POSIX 1003.2 regular expressions
+.SH DESCRIPTION
+Regular expressions (``RE''s),
+as defined in POSIX 1003.2, come in two forms:
+modern REs (roughly those of
+.IR egrep ;
+1003.2 calls these ``extended'' REs)
+and obsolete REs (roughly those of
+.IR ed ;
+1003.2 ``basic'' REs).
+Obsolete REs mostly exist for backward compatibility in some old programs;
+they will be discussed at the end.
+1003.2 leaves some aspects of RE syntax and semantics open;
+`\(dg' marks decisions on these aspects that
+may not be fully portable to other 1003.2 implementations.
+.PP
+A (modern) RE is one\(dg or more non-empty\(dg \fIbranches\fR,
+separated by `|'.
+It matches anything that matches one of the branches.
+.PP
+A branch is one\(dg or more \fIpieces\fR, concatenated.
+It matches a match for the first, followed by a match for the second, etc.
+.PP
+A piece is an \fIatom\fR possibly followed
+by a single\(dg `*', `+', `?', or \fIbound\fR.
+An atom followed by `*' matches a sequence of 0 or more matches of the atom.
+An atom followed by `+' matches a sequence of 1 or more matches of the atom.
+An atom followed by `?' matches a sequence of 0 or 1 matches of the atom.
+.PP
+A \fIbound\fR is `{' followed by an unsigned decimal integer,
+possibly followed by `,'
+possibly followed by another unsigned decimal integer,
+always followed by `}'.
+The integers must lie between 0 and RE_DUP_MAX (255\(dg) inclusive,
+and if there are two of them, the first may not exceed the second.
+An atom followed by a bound containing one integer \fIi\fR
+and no comma matches
+a sequence of exactly \fIi\fR matches of the atom.
+An atom followed by a bound
+containing one integer \fIi\fR and a comma matches
+a sequence of \fIi\fR or more matches of the atom.
+An atom followed by a bound
+containing two integers \fIi\fR and \fIj\fR matches
+a sequence of \fIi\fR through \fIj\fR (inclusive) matches of the atom.
+.PP
+An atom is a regular expression enclosed in `()' (matching a match for the
+regular expression),
+an empty set of `()' (matching the null string)\(dg,
+a \fIbracket expression\fR (see below), `.'
+(matching any single character), `^' (matching the null string at the
+beginning of a line), `$' (matching the null string at the
+end of a line), a `\e' followed by one of the characters
+`^.[$()|*+?{\e'
+(matching that character taken as an ordinary character),
+a `\e' followed by any other character\(dg
+(matching that character taken as an ordinary character,
+as if the `\e' had not been present\(dg),
+or a single character with no other significance (matching that character).
+A `{' followed by a character other than a digit is an ordinary
+character, not the beginning of a bound\(dg.
+It is illegal to end an RE with `\e'.
+.PP
+A \fIbracket expression\fR is a list of characters enclosed in `[]'.
+It normally matches any single character from the list (but see below).
+If the list begins with `^',
+it matches any single character
+(but see below) \fInot\fR from the rest of the list.
+If two characters in the list are separated by `\-', this is shorthand
+for the full \fIrange\fR of characters between those two (inclusive) in the
+collating sequence,
+e.g. `[0\-9]' in ASCII matches any decimal digit.
+It is illegal\(dg for two ranges to share an
+endpoint, e.g. `a\-c\-e'.
+Ranges are very collating-sequence-dependent,
+and portable programs should avoid relying on them.
+.PP
+To include a literal `]' in the list, make it the first character
+(following a possible `^').
+To include a literal `\-', make it the first or last character,
+or the second endpoint of a range.
+To use a literal `\-' as the first endpoint of a range,
+enclose it in `[.' and `.]' to make it a collating element (see below).
+With the exception of these and some combinations using `[' (see next
+paragraphs), all other special characters, including `\e', lose their
+special significance within a bracket expression.
+.PP
+Within a bracket expression, a collating element (a character,
+a multi-character sequence that collates as if it were a single character,
+or a collating-sequence name for either)
+enclosed in `[.' and `.]' stands for the
+sequence of characters of that collating element.
+The sequence is a single element of the bracket expression's list.
+A bracket expression containing a multi-character collating element 
+can thus match more than one character,
+e.g. if the collating sequence includes a `ch' collating element,
+then the RE `[[.ch.]]*c' matches the first five characters
+of `chchcc'.
+.PP
+Within a bracket expression, a collating element enclosed in `[=' and
+`=]' is an equivalence class, standing for the sequences of characters
+of all collating elements equivalent to that one, including itself.
+(If there are no other equivalent collating elements,
+the treatment is as if the enclosing delimiters were `[.' and `.]'.)
+For example, if o and \o'o^' are the members of an equivalence class,
+then `[[=o=]]', `[[=\o'o^'=]]', and `[o\o'o^']' are all synonymous.
+An equivalence class may not\(dg be an endpoint
+of a range.
+.PP
+Within a bracket expression, the name of a \fIcharacter class\fR enclosed
+in `[:' and `:]' stands for the list of all characters belonging to that
+class.
+Standard character class names are:
+.PP
+.RS
+.nf
+.ta 3c 6c 9c
+alnum	digit	punct
+alpha	graph	space
+blank	lower	upper
+cntrl	print	xdigit
+.fi
+.RE
+.PP
+These stand for the character classes defined in
+.IR ctype (3).
+A locale may provide others.
+A character class may not be used as an endpoint of a range.
+.PP
+There are two special cases\(dg of bracket expressions:
+the bracket expressions `[[:<:]]' and `[[:>:]]' match the null string at
+the beginning and end of a word respectively.
+A word is defined as a sequence of
+word characters
+which is neither preceded nor followed by
+word characters.
+A word character is an
+.I alnum
+character (as defined by
+.IR ctype (3))
+or an underscore.
+This is an extension,
+compatible with but not specified by POSIX 1003.2,
+and should be used with
+caution in software intended to be portable to other systems.
+.PP
+In the event that an RE could match more than one substring of a given
+string,
+the RE matches the one starting earliest in the string.
+If the RE could match more than one substring starting at that point,
+it matches the longest.
+Subexpressions also match the longest possible substrings, subject to
+the constraint that the whole match be as long as possible,
+with subexpressions starting earlier in the RE taking priority over
+ones starting later.
+Note that higher-level subexpressions thus take priority over
+their lower-level component subexpressions.
+.PP
+Match lengths are measured in characters, not collating elements.
+A null string is considered longer than no match at all.
+For example,
+`bb*' matches the three middle characters of `abbbc',
+`(wee|week)(knights|nights)' matches all ten characters of `weeknights',
+when `(.*).*' is matched against `abc' the parenthesized subexpression
+matches all three characters, and
+when `(a*)*' is matched against `bc' both the whole RE and the parenthesized
+subexpression match the null string.
+.PP
+If case-independent matching is specified,
+the effect is much as if all case distinctions had vanished from the
+alphabet.
+When an alphabetic that exists in multiple cases appears as an
+ordinary character outside a bracket expression, it is effectively
+transformed into a bracket expression containing both cases,
+e.g. `x' becomes `[xX]'.
+When it appears inside a bracket expression, all case counterparts
+of it are added to the bracket expression, so that (e.g.) `[x]'
+becomes `[xX]' and `[^x]' becomes `[^xX]'.
+.PP
+No particular limit is imposed on the length of REs\(dg.
+Programs intended to be portable should not employ REs longer
+than 256 bytes,
+as an implementation can refuse to accept such REs and remain
+POSIX-compliant.
+.PP
+Obsolete (``basic'') regular expressions differ in several respects.
+`|', `+', and `?' are ordinary characters and there is no equivalent
+for their functionality.
+The delimiters for bounds are `\e{' and `\e}',
+with `{' and `}' by themselves ordinary characters.
+The parentheses for nested subexpressions are `\e(' and `\e)',
+with `(' and `)' by themselves ordinary characters.
+`^' is an ordinary character except at the beginning of the
+RE or\(dg the beginning of a parenthesized subexpression,
+`$' is an ordinary character except at the end of the
+RE or\(dg the end of a parenthesized subexpression,
+and `*' is an ordinary character if it appears at the beginning of the
+RE or the beginning of a parenthesized subexpression
+(after a possible leading `^').
+Finally, there is one new type of atom, a \fIback reference\fR:
+`\e' followed by a non-zero decimal digit \fId\fR
+matches the same sequence of characters
+matched by the \fId\fRth parenthesized subexpression
+(numbering subexpressions by the positions of their opening parentheses,
+left to right),
+so that (e.g.) `\e([bc]\e)\e1' matches `bb' or `cc' but not `bc'.
+.SH SEE ALSO
+regex(3)
+.PP
+POSIX 1003.2, section 2.8 (Regular Expression Notation).
+.SH HISTORY
+Written by Henry Spencer, based on the 1003.2 spec.
+.SH BUGS
+Having two kinds of REs is a botch.
+.PP
+The current 1003.2 spec says that `)' is an ordinary character in
+the absence of an unmatched `(';
+this was an unintentional result of a wording error,
+and change is likely.
+Avoid relying on it.
+.PP
+Back references are a dreadful botch,
+posing major problems for efficient implementations.
+They are also somewhat vaguely defined
+(does
+`a\e(\e(b\e)*\e2\e)*d' match `abbbd'?).
+Avoid using them.
+.PP
+1003.2's specification of case-independent matching is vague.
+The ``one case implies all cases'' definition given above
+is current consensus among implementors as to the right interpretation.
+.PP
+The syntax for word boundaries is incredibly ugly.
diff --git a/regex/regex.h b/regex/regex.h
new file mode 100644
index 0000000..e3f81bf
--- /dev/null
+++ b/regex/regex.h
@@ -0,0 +1,74 @@
+#ifndef _REGEX_H_
+#define	_REGEX_H_	/* never again */
+/* ========= begin header generated by ./mkh ========= */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* === regex2.h === */
+typedef off_t regoff_t;
+typedef struct {
+	int re_magic;
+	size_t re_nsub;		/* number of parenthesized subexpressions */
+	const char *re_endp;	/* end pointer for REG_PEND */
+	struct re_guts *re_g;	/* none of your business :-) */
+} regex_t;
+typedef struct {
+	regoff_t rm_so;		/* start of match */
+	regoff_t rm_eo;		/* end of match */
+} regmatch_t;
+
+
+/* === regcomp.c === */
+extern int notbuiltin_regcomp(regex_t *, const char *, int);
+#define	REG_BASIC	0000
+#define	REG_EXTENDED	0001
+#define	REG_ICASE	0002
+#define	REG_NOSUB	0004
+#define	REG_NEWLINE	0010
+#define	REG_NOSPEC	0020
+#define	REG_PEND	0040
+#define	REG_DUMP	0200
+
+
+/* === regerror.c === */
+#define	REG_OKAY	 0
+#define	REG_NOMATCH	 1
+#define	REG_BADPAT	 2
+#define	REG_ECOLLATE	 3
+#define	REG_ECTYPE	 4
+#define	REG_EESCAPE	 5
+#define	REG_ESUBREG	 6
+#define	REG_EBRACK	 7
+#define	REG_EPAREN	 8
+#define	REG_EBRACE	 9
+#define	REG_BADBR	10
+#define	REG_ERANGE	11
+#define	REG_ESPACE	12
+#define	REG_BADRPT	13
+#define	REG_EMPTY	14
+#define	REG_ASSERT	15
+#define	REG_INVARG	16
+#define	REG_ATOI	255	/* convert name to number (!) */
+#define	REG_ITOA	0400	/* convert number to name (!) */
+extern size_t notbuiltin_regerror(int, const regex_t *, char *, size_t);
+
+
+/* === regexec.c === */
+extern int notbuiltin_regexec(const regex_t *, const char *, size_t, regmatch_t [], int);
+#define	REG_NOTBOL	00001
+#define	REG_NOTEOL	00002
+#define	REG_STARTEND	00004
+#define	REG_TRACE	00400	/* tracing of execution */
+#define	REG_LARGE	01000	/* force large representation */
+#define	REG_BACKR	02000	/* force use of backref code */
+
+
+/* === regfree.c === */
+extern void notbuiltin_regfree(regex_t *);
+
+#ifdef __cplusplus
+}
+#endif
+/* ========= end header generated by ./mkh ========= */
+#endif
diff --git a/regex/regex2.h b/regex/regex2.h
new file mode 100644
index 0000000..58fd8d8
--- /dev/null
+++ b/regex/regex2.h
@@ -0,0 +1,134 @@
+/*
+ * First, the stuff that ends up in the outside-world include file
+ = typedef off_t regoff_t;
+ = typedef struct {
+ = 	int re_magic;
+ = 	size_t re_nsub;		// number of parenthesized subexpressions
+ = 	const char *re_endp;	// end pointer for REG_PEND
+ = 	struct re_guts *re_g;	// none of your business :-)
+ = } regex_t;
+ = typedef struct {
+ = 	regoff_t rm_so;		// start of match
+ = 	regoff_t rm_eo;		// end of match
+ = } regmatch_t;
+ */
+/*
+ * internals of regex_t
+ */
+#define	MAGIC1	((('r'^0200)<<8) | 'e')
+
+/*
+ * The internal representation is a *strip*, a sequence of
+ * operators ending with an endmarker.  (Some terminology etc. is a
+ * historical relic of earlier versions which used multiple strips.)
+ * Certain oddities in the representation are there to permit running
+ * the machinery backwards; in particular, any deviation from sequential
+ * flow must be marked at both its source and its destination.  Some
+ * fine points:
+ *
+ * - OPLUS_ and O_PLUS are *inside* the loop they create.
+ * - OQUEST_ and O_QUEST are *outside* the bypass they create.
+ * - OCH_ and O_CH are *outside* the multi-way branch they create, while
+ *   OOR1 and OOR2 are respectively the end and the beginning of one of
+ *   the branches.  Note that there is an implicit OOR2 following OCH_
+ *   and an implicit OOR1 preceding O_CH.
+ *
+ * In state representations, an operator's bit is on to signify a state
+ * immediately *preceding* "execution" of that operator.
+ */
+typedef long sop;		/* strip operator */
+typedef long sopno;
+#define	OPRMASK	0x7c000000
+#define	OPDMASK	0x03ffffff
+#define	OPSHIFT	(26)
+#define	OP(n)	((n)&OPRMASK)
+#define	OPND(n)	((n)&OPDMASK)
+#define	SOP(op, opnd)	((op)|(opnd))
+/* operators			   meaning	operand			*/
+/*						(back, fwd are offsets)	*/
+#define	OEND	(1<<OPSHIFT)	/* endmarker	-			*/
+#define	OCHAR	(2<<OPSHIFT)	/* character	unsigned char		*/
+#define	OBOL	(3<<OPSHIFT)	/* left anchor	-			*/
+#define	OEOL	(4<<OPSHIFT)	/* right anchor	-			*/
+#define	OANY	(5<<OPSHIFT)	/* .		-			*/
+#define	OANYOF	(6<<OPSHIFT)	/* [...]	set number		*/
+#define	OBACK_	(7<<OPSHIFT)	/* begin \d	paren number		*/
+#define	O_BACK	(8<<OPSHIFT)	/* end \d	paren number		*/
+#define	OPLUS_	(9<<OPSHIFT)	/* + prefix	fwd to suffix		*/
+#define	O_PLUS	(10<<OPSHIFT)	/* + suffix	back to prefix		*/
+#define	OQUEST_	(11<<OPSHIFT)	/* ? prefix	fwd to suffix		*/
+#define	O_QUEST	(12<<OPSHIFT)	/* ? suffix	back to prefix		*/
+#define	OLPAREN	(13<<OPSHIFT)	/* (		fwd to )		*/
+#define	ORPAREN	(14<<OPSHIFT)	/* )		back to (		*/
+#define	OCH_	(15<<OPSHIFT)	/* begin choice	fwd to OOR2		*/
+#define	OOR1	(16<<OPSHIFT)	/* | pt. 1	back to OOR1 or OCH_	*/
+#define	OOR2	(17<<OPSHIFT)	/* | pt. 2	fwd to OOR2 or O_CH	*/
+#define	O_CH	(18<<OPSHIFT)	/* end choice	back to OOR1		*/
+#define	OBOW	(19<<OPSHIFT)	/* begin word	-			*/
+#define	OEOW	(20<<OPSHIFT)	/* end word	-			*/
+
+/*
+ * Structure for [] character-set representation.  Character sets are
+ * done as bit vectors, grouped 8 to a byte vector for compactness.
+ * The individual set therefore has both a pointer to the byte vector
+ * and a mask to pick out the relevant bit of each byte.  A hash code
+ * simplifies testing whether two sets could be identical.
+ *
+ * This will get trickier for multicharacter collating elements.  As
+ * preliminary hooks for dealing with such things, we also carry along
+ * a string of multi-character elements, and decide the size of the
+ * vectors at run time.
+ */
+typedef struct {
+	uch *ptr;		/* -> uch [csetsize] */
+	uch mask;		/* bit within array */
+	uch hash;		/* hash code */
+	size_t smultis;
+	char *multis;		/* -> char[smulti]  ab\0cd\0ef\0\0 */
+} cset;
+/* note that CHadd and CHsub are unsafe, and CHIN doesn't yield 0/1 */
+#define	CHadd(cs, c)	((cs)->ptr[(uch)(c)] |= (cs)->mask, (cs)->hash += (c))
+#define	CHsub(cs, c)	((cs)->ptr[(uch)(c)] &= ~(cs)->mask, (cs)->hash -= (c))
+#define	CHIN(cs, c)	((cs)->ptr[(uch)(c)] & (cs)->mask)
+#define	MCadd(p, cs, cp)	mcadd(p, cs, cp)	/* regcomp() internal fns */
+#define	MCsub(p, cs, cp)	mcsub(p, cs, cp)
+#define	MCin(p, cs, cp)	mcin(p, cs, cp)
+
+/* stuff for character categories */
+typedef unsigned char cat_t;
+
+/*
+ * main compiled-expression structure
+ */
+struct re_guts {
+	int magic;
+#		define	MAGIC2	((('R'^0200)<<8)|'E')
+	sop *strip;		/* malloced area for strip */
+	int csetsize;		/* number of bits in a cset vector */
+	int ncsets;		/* number of csets in use */
+	cset *sets;		/* -> cset [ncsets] */
+	uch *setbits;		/* -> uch[csetsize][ncsets/CHAR_BIT] */
+	int cflags;		/* copy of regcomp() cflags argument */
+	sopno nstates;		/* = number of sops */
+	sopno firststate;	/* the initial OEND (normally 0) */
+	sopno laststate;	/* the final OEND */
+	int iflags;		/* internal flags */
+#		define	USEBOL	01	/* used ^ */
+#		define	USEEOL	02	/* used $ */
+#		define	BAD	04	/* something wrong */
+	int nbol;		/* number of ^ used */
+	int neol;		/* number of $ used */
+	int ncategories;	/* how many character categories */
+	cat_t *categories;	/* ->catspace[-CHAR_MIN] */
+	char *must;		/* match must contain this string */
+	int mlen;		/* length of must */
+	size_t nsub;		/* copy of re_nsub */
+	int backrefs;		/* does it use back references? */
+	sopno nplus;		/* how deep does it nest +s? */
+	/* catspace must be last */
+	cat_t catspace[1];	/* actually [NC] */
+};
+
+/* misc utilities */
+#define	OUT	(CHAR_MAX+1)	/* a non-character value */
+#define	ISWORD(c)	(isalnum(c) || (c) == '_')
diff --git a/regex/regexec.c b/regex/regexec.c
new file mode 100644
index 0000000..6ab320e
--- /dev/null
+++ b/regex/regexec.c
@@ -0,0 +1,138 @@
+/*
+ * the outer shell of regexec()
+ *
+ * This file includes engine.c *twice*, after muchos fiddling with the
+ * macros that code uses.  This lets the same code operate on two different
+ * representations for state sets.
+ */
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <ctype.h>
+#include <regex.h>
+
+#include "utils.h"
+#include "regex2.h"
+
+static int nope = 0;		/* for use in asserts; shuts lint up */
+
+/* macros for manipulating states, small version */
+#define	states	unsigned
+#define	states1	unsigned	/* for later use in regexec() decision */
+#define	CLEAR(v)	((v) = 0)
+#define	SET0(v, n)	((v) &= ~((unsigned)1 << (n)))
+#define	SET1(v, n)	((v) |= (unsigned)1 << (n))
+#define	ISSET(v, n)	((v) & ((unsigned)1 << (n)))
+#define	ASSIGN(d, s)	((d) = (s))
+#define	EQ(a, b)	((a) == (b))
+#define	STATEVARS	int dummy	/* dummy version */
+#define	STATESETUP(m, n)	/* nothing */
+#define	STATETEARDOWN(m)	/* nothing */
+#define	SETUP(v)	((v) = 0)
+#define	onestate	unsigned
+#define	INIT(o, n)	((o) = (unsigned)1 << (n))
+#define	INC(o)	((o) <<= 1)
+#define	ISSTATEIN(v, o)	((v) & (o))
+/* some abbreviations; note that some of these know variable names! */
+/* do "if I'm here, I can also be there" etc without branches */
+#define	FWD(dst, src, n)	((dst) |= ((unsigned)(src)&(here)) << (n))
+#define	BACK(dst, src, n)	((dst) |= ((unsigned)(src)&(here)) >> (n))
+#define	ISSETBACK(v, n)	((v) & ((unsigned)here >> (n)))
+/* function names */
+#define SNAMES			/* engine.c looks after details */
+
+#include "engine.c"
+
+/* now undo things */
+#undef	states
+#undef	CLEAR
+#undef	SET0
+#undef	SET1
+#undef	ISSET
+#undef	ASSIGN
+#undef	EQ
+#undef	STATEVARS
+#undef	STATESETUP
+#undef	STATETEARDOWN
+#undef	SETUP
+#undef	onestate
+#undef	INIT
+#undef	INC
+#undef	ISSTATEIN
+#undef	FWD
+#undef	BACK
+#undef	ISSETBACK
+#undef	SNAMES
+
+/* macros for manipulating states, large version */
+#define	states	char *
+#define	CLEAR(v)	memset(v, 0, m->g->nstates)
+#define	SET0(v, n)	((v)[n] = 0)
+#define	SET1(v, n)	((v)[n] = 1)
+#define	ISSET(v, n)	((v)[n])
+#define	ASSIGN(d, s)	memcpy(d, s, m->g->nstates)
+#define	EQ(a, b)	(memcmp(a, b, m->g->nstates) == 0)
+#define	STATEVARS	int vn; char *space
+#define	STATESETUP(m, nv)	{ (m)->space = malloc((nv)*(m)->g->nstates); \
+				if ((m)->space == NULL) return(REG_ESPACE); \
+				(m)->vn = 0; }
+#define	STATETEARDOWN(m)	{ free((m)->space); }
+#define	SETUP(v)	((v) = &m->space[m->vn++ * m->g->nstates])
+#define	onestate	int
+#define	INIT(o, n)	((o) = (n))
+#define	INC(o)	((o)++)
+#define	ISSTATEIN(v, o)	((v)[o])
+/* some abbreviations; note that some of these know variable names! */
+/* do "if I'm here, I can also be there" etc without branches */
+#define	FWD(dst, src, n)	((dst)[here+(n)] |= (src)[here])
+#define	BACK(dst, src, n)	((dst)[here-(n)] |= (src)[here])
+#define	ISSETBACK(v, n)	((v)[here - (n)])
+/* function names */
+#define	LNAMES			/* flag */
+
+#include "engine.c"
+
+/*
+ - regexec - interface for matching
+ = extern int notbuiltin_regexec(const regex_t *, const char *, size_t, \
+ =					regmatch_t [], int);
+ = #define	REG_NOTBOL	00001
+ = #define	REG_NOTEOL	00002
+ = #define	REG_STARTEND	00004
+ = #define	REG_TRACE	00400	// tracing of execution
+ = #define	REG_LARGE	01000	// force large representation
+ = #define	REG_BACKR	02000	// force use of backref code
+ *
+ * We put this here so we can exploit knowledge of the state representation
+ * when choosing which matcher to call.  Also, by this point the matchers
+ * have been prototyped.
+ */
+int				/* 0 success, REG_NOMATCH failure */
+notbuiltin_regexec(preg, string, nmatch, pmatch, eflags)
+const regex_t *preg;
+const char *string;
+size_t nmatch;
+regmatch_t pmatch[];
+int eflags;
+{
+	register struct re_guts *g = preg->re_g;
+#ifdef REDEBUG
+#	define	GOODFLAGS(f)	(f)
+#else
+#	define	GOODFLAGS(f)	((f)&(REG_NOTBOL|REG_NOTEOL|REG_STARTEND))
+#endif
+
+	if (preg->re_magic != MAGIC1 || g->magic != MAGIC2)
+		return(REG_BADPAT);
+	assert(!(g->iflags&BAD));
+	if (g->iflags&BAD)		/* backstop for no-debug case */
+		return(REG_BADPAT);
+	eflags = GOODFLAGS(eflags);
+
+	if (g->nstates <= CHAR_BIT*sizeof(states1) && !(eflags&REG_LARGE))
+		return(smatcher(g, (char *)string, nmatch, pmatch, eflags));
+	else
+		return(lmatcher(g, (char *)string, nmatch, pmatch, eflags));
+}
diff --git a/regex/regfree.c b/regex/regfree.c
new file mode 100644
index 0000000..bfcde53
--- /dev/null
+++ b/regex/regfree.c
@@ -0,0 +1,37 @@
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <regex.h>
+
+#include "utils.h"
+#include "regex2.h"
+
+/*
+ - regfree - free everything
+ = extern void notbuiltin_regfree(regex_t *);
+ */
+void
+notbuiltin_regfree(preg)
+regex_t *preg;
+{
+	register struct re_guts *g;
+
+	if (preg->re_magic != MAGIC1)	/* oops */
+		return;			/* nice to complain, but hard */
+
+	g = preg->re_g;
+	if (g == NULL || g->magic != MAGIC2)	/* oops again */
+		return;
+	preg->re_magic = 0;		/* mark it invalid */
+	g->magic = 0;			/* mark it invalid */
+
+	if (g->strip != NULL)
+		free((char *)g->strip);
+	if (g->sets != NULL)
+		free((char *)g->sets);
+	if (g->setbits != NULL)
+		free((char *)g->setbits);
+	if (g->must != NULL)
+		free(g->must);
+	free((char *)g);
+}
diff --git a/regex/split.c b/regex/split.c
new file mode 100644
index 0000000..188bdb7
--- /dev/null
+++ b/regex/split.c
@@ -0,0 +1,316 @@
+#include <stdio.h>
+#include <string.h>
+
+/*
+ - split - divide a string into fields, like awk split()
+ = int split(char *string, char *fields[], int nfields, char *sep);
+ */
+int				/* number of fields, including overflow */
+split(string, fields, nfields, sep)
+char *string;
+char *fields[];			/* list is not NULL-terminated */
+int nfields;			/* number of entries available in fields[] */
+char *sep;			/* "" white, "c" single char, "ab" [ab]+ */
+{
+	register char *p = string;
+	register char c;			/* latest character */
+	register char sepc = sep[0];
+	register char sepc2;
+	register int fn;
+	register char **fp = fields;
+	register char *sepp;
+	register int trimtrail;
+
+	/* white space */
+	if (sepc == '\0') {
+		while ((c = *p++) == ' ' || c == '\t')
+			continue;
+		p--;
+		trimtrail = 1;
+		sep = " \t";	/* note, code below knows this is 2 long */
+		sepc = ' ';
+	} else
+		trimtrail = 0;
+	sepc2 = sep[1];		/* now we can safely pick this up */
+
+	/* catch empties */
+	if (*p == '\0')
+		return(0);
+
+	/* single separator */
+	if (sepc2 == '\0') {
+		fn = nfields;
+		for (;;) {
+			*fp++ = p;
+			fn--;
+			if (fn == 0)
+				break;
+			while ((c = *p++) != sepc)
+				if (c == '\0')
+					return(nfields - fn);
+			*(p-1) = '\0';
+		}
+		/* we have overflowed the fields vector -- just count them */
+		fn = nfields;
+		for (;;) {
+			while ((c = *p++) != sepc)
+				if (c == '\0')
+					return(fn);
+			fn++;
+		}
+		/* not reached */
+	}
+
+	/* two separators */
+	if (sep[2] == '\0') {
+		fn = nfields;
+		for (;;) {
+			*fp++ = p;
+			fn--;
+			while ((c = *p++) != sepc && c != sepc2)
+				if (c == '\0') {
+					if (trimtrail && **(fp-1) == '\0')
+						fn++;
+					return(nfields - fn);
+				}
+			if (fn == 0)
+				break;
+			*(p-1) = '\0';
+			while ((c = *p++) == sepc || c == sepc2)
+				continue;
+			p--;
+		}
+		/* we have overflowed the fields vector -- just count them */
+		fn = nfields;
+		while (c != '\0') {
+			while ((c = *p++) == sepc || c == sepc2)
+				continue;
+			p--;
+			fn++;
+			while ((c = *p++) != '\0' && c != sepc && c != sepc2)
+				continue;
+		}
+		/* might have to trim trailing white space */
+		if (trimtrail) {
+			p--;
+			while ((c = *--p) == sepc || c == sepc2)
+				continue;
+			p++;
+			if (*p != '\0') {
+				if (fn == nfields+1)
+					*p = '\0';
+				fn--;
+			}
+		}
+		return(fn);
+	}
+
+	/* n separators */
+	fn = 0;
+	for (;;) {
+		if (fn < nfields)
+			*fp++ = p;
+		fn++;
+		for (;;) {
+			c = *p++;
+			if (c == '\0')
+				return(fn);
+			sepp = sep;
+			while ((sepc = *sepp++) != '\0' && sepc != c)
+				continue;
+			if (sepc != '\0')	/* it was a separator */
+				break;
+		}
+		if (fn < nfields)
+			*(p-1) = '\0';
+		for (;;) {
+			c = *p++;
+			sepp = sep;
+			while ((sepc = *sepp++) != '\0' && sepc != c)
+				continue;
+			if (sepc == '\0')	/* it wasn't a separator */
+				break;
+		}
+		p--;
+	}
+
+	/* not reached */
+}
+
+#ifdef TEST_SPLIT
+
+
+/*
+ * test program
+ * pgm		runs regression
+ * pgm sep	splits stdin lines by sep
+ * pgm str sep	splits str by sep
+ * pgm str sep n	splits str by sep n times
+ */
+int
+main(argc, argv)
+int argc;
+char *argv[];
+{
+	char buf[512];
+	register int n;
+#	define	MNF	10
+	char *fields[MNF];
+
+	if (argc > 4)
+		for (n = atoi(argv[3]); n > 0; n--) {
+			(void) strcpy(buf, argv[1]);
+		}
+	else if (argc > 3)
+		for (n = atoi(argv[3]); n > 0; n--) {
+			(void) strcpy(buf, argv[1]);
+			(void) split(buf, fields, MNF, argv[2]);
+		}
+	else if (argc > 2)
+		dosplit(argv[1], argv[2]);
+	else if (argc > 1)
+		while (fgets(buf, sizeof(buf), stdin) != NULL) {
+			buf[strlen(buf)-1] = '\0';	/* stomp newline */
+			dosplit(buf, argv[1]);
+		}
+	else
+		regress();
+
+	exit(0);
+}
+
+dosplit(string, seps)
+char *string;
+char *seps;
+{
+#	define	NF	5
+	char *fields[NF];
+	register int nf;
+
+	nf = split(string, fields, NF, seps);
+	print(nf, NF, fields);
+}
+
+print(nf, nfp, fields)
+int nf;
+int nfp;
+char *fields[];
+{
+	register int fn;
+	register int bound;
+
+	bound = (nf > nfp) ? nfp : nf;
+	printf("%d:\t", nf);
+	for (fn = 0; fn < bound; fn++)
+		printf("\"%s\"%s", fields[fn], (fn+1 < nf) ? ", " : "\n");
+}
+
+#define	RNF	5		/* some table entries know this */
+struct {
+	char *str;
+	char *seps;
+	int nf;
+	char *fi[RNF];
+} tests[] = {
+	"",		" ",	0,	{ "" },
+	" ",		" ",	2,	{ "", "" },
+	"x",		" ",	1,	{ "x" },
+	"xy",		" ",	1,	{ "xy" },
+	"x y",		" ",	2,	{ "x", "y" },
+	"abc def  g ",	" ",	5,	{ "abc", "def", "", "g", "" },
+	"  a bcd",	" ",	4,	{ "", "", "a", "bcd" },
+	"a b c d e f",	" ",	6,	{ "a", "b", "c", "d", "e f" },
+	" a b c d ",	" ",	6,	{ "", "a", "b", "c", "d " },
+
+	"",		" _",	0,	{ "" },
+	" ",		" _",	2,	{ "", "" },
+	"x",		" _",	1,	{ "x" },
+	"x y",		" _",	2,	{ "x", "y" },
+	"ab _ cd",	" _",	2,	{ "ab", "cd" },
+	" a_b  c ",	" _",	5,	{ "", "a", "b", "c", "" },
+	"a b c_d e f",	" _",	6,	{ "a", "b", "c", "d", "e f" },
+	" a b c d ",	" _",	6,	{ "", "a", "b", "c", "d " },
+
+	"",		" _~",	0,	{ "" },
+	" ",		" _~",	2,	{ "", "" },
+	"x",		" _~",	1,	{ "x" },
+	"x y",		" _~",	2,	{ "x", "y" },
+	"ab _~ cd",	" _~",	2,	{ "ab", "cd" },
+	" a_b  c~",	" _~",	5,	{ "", "a", "b", "c", "" },
+	"a b_c d~e f",	" _~",	6,	{ "a", "b", "c", "d", "e f" },
+	"~a b c d ",	" _~",	6,	{ "", "a", "b", "c", "d " },
+
+	"",		" _~-",	0,	{ "" },
+	" ",		" _~-",	2,	{ "", "" },
+	"x",		" _~-",	1,	{ "x" },
+	"x y",		" _~-",	2,	{ "x", "y" },
+	"ab _~- cd",	" _~-",	2,	{ "ab", "cd" },
+	" a_b  c~",	" _~-",	5,	{ "", "a", "b", "c", "" },
+	"a b_c-d~e f",	" _~-",	6,	{ "a", "b", "c", "d", "e f" },
+	"~a-b c d ",	" _~-",	6,	{ "", "a", "b", "c", "d " },
+
+	"",		"  ",	0,	{ "" },
+	" ",		"  ",	2,	{ "", "" },
+	"x",		"  ",	1,	{ "x" },
+	"xy",		"  ",	1,	{ "xy" },
+	"x y",		"  ",	2,	{ "x", "y" },
+	"abc def  g ",	"  ",	4,	{ "abc", "def", "g", "" },
+	"  a bcd",	"  ",	3,	{ "", "a", "bcd" },
+	"a b c d e f",	"  ",	6,	{ "a", "b", "c", "d", "e f" },
+	" a b c d ",	"  ",	6,	{ "", "a", "b", "c", "d " },
+
+	"",		"",	0,	{ "" },
+	" ",		"",	0,	{ "" },
+	"x",		"",	1,	{ "x" },
+	"xy",		"",	1,	{ "xy" },
+	"x y",		"",	2,	{ "x", "y" },
+	"abc def  g ",	"",	3,	{ "abc", "def", "g" },
+	"\t a bcd",	"",	2,	{ "a", "bcd" },
+	"  a \tb\t c ",	"",	3,	{ "a", "b", "c" },
+	"a b c d e ",	"",	5,	{ "a", "b", "c", "d", "e" },
+	"a b\tc d e f",	"",	6,	{ "a", "b", "c", "d", "e f" },
+	" a b c d e f ",	"",	6,	{ "a", "b", "c", "d", "e f " },
+
+	NULL,		NULL,	0,	{ NULL },
+};
+
+regress()
+{
+	char buf[512];
+	register int n;
+	char *fields[RNF+1];
+	register int nf;
+	register int i;
+	register int printit;
+	register char *f;
+
+	for (n = 0; tests[n].str != NULL; n++) {
+		(void) strcpy(buf, tests[n].str);
+		fields[RNF] = NULL;
+		nf = split(buf, fields, RNF, tests[n].seps);
+		printit = 0;
+		if (nf != tests[n].nf) {
+			printf("split `%s' by `%s' gave %d fields, not %d\n",
+				tests[n].str, tests[n].seps, nf, tests[n].nf);
+			printit = 1;
+		} else if (fields[RNF] != NULL) {
+			printf("split() went beyond array end\n");
+			printit = 1;
+		} else {
+			for (i = 0; i < nf && i < RNF; i++) {
+				f = fields[i];
+				if (f == NULL)
+					f = "(NULL)";
+				if (strcmp(f, tests[n].fi[i]) != 0) {
+					printf("split `%s' by `%s', field %d is `%s', not `%s'\n",
+						tests[n].str, tests[n].seps,
+						i, fields[i], tests[n].fi[i]);
+					printit = 1;
+				}
+			}
+		}
+		if (printit)
+			print(nf, RNF, fields);
+	}
+}
+#endif
diff --git a/regex/tests b/regex/tests
new file mode 100644
index 0000000..e4d928d
--- /dev/null
+++ b/regex/tests
@@ -0,0 +1,477 @@
+# regular expression test set
+# Lines are at least three fields, separated by one or more tabs.  "" stands
+# for an empty field.  First field is an RE.  Second field is flags.  If
+# C flag given, regcomp() is expected to fail, and the third field is the
+# error name (minus the leading REG_).
+#
+# Otherwise it is expected to succeed, and the third field is the string to
+# try matching it against.  If there is no fourth field, the match is
+# expected to fail.  If there is a fourth field, it is the substring that
+# the RE is expected to match.  If there is a fifth field, it is a comma-
+# separated list of what the subexpressions should match, with - indicating
+# no match for that one.  In both the fourth and fifth fields, a (sub)field
+# starting with @ indicates that the (sub)expression is expected to match
+# a null string followed by the stuff after the @; this provides a way to
+# test where null strings match.  The character `N' in REs and strings
+# is newline, `S' is space, `T' is tab, `Z' is NUL.
+#
+# The full list of flags:
+#	-	placeholder, does nothing
+#	b	RE is a BRE, not an ERE
+#	&	try it as both an ERE and a BRE
+#	C	regcomp() error expected, third field is error name
+#	i	REG_ICASE
+#	m	("mundane") REG_NOSPEC
+#	s	REG_NOSUB (not really testable)
+#	n	REG_NEWLINE
+#	^	REG_NOTBOL
+#	$	REG_NOTEOL
+#	#	REG_STARTEND (see below)
+#	p	REG_PEND
+#
+# For REG_STARTEND, the start/end offsets are those of the substring
+# enclosed in ().
+
+# basics
+a		&	a	a
+abc		&	abc	abc
+abc|de		-	abc	abc
+a|b|c		-	abc	a
+
+# parentheses and perversions thereof
+a(b)c		-	abc	abc
+a\(b\)c		b	abc	abc
+a(		C	EPAREN
+a(		b	a(	a(
+a\(		-	a(	a(
+a\(		bC	EPAREN
+a\(b		bC	EPAREN
+a(b		C	EPAREN
+a(b		b	a(b	a(b
+# gag me with a right parenthesis -- 1003.2 goofed here (my fault, partly)
+a)		-	a)	a)
+)		-	)	)
+# end gagging (in a just world, those *should* give EPAREN)
+a)		b	a)	a)
+a\)		bC	EPAREN
+\)		bC	EPAREN
+a()b		-	ab	ab
+a\(\)b		b	ab	ab
+
+# anchoring and REG_NEWLINE
+^abc$		&	abc	abc
+a^b		-	a^b
+a^b		b	a^b	a^b
+a$b		-	a$b
+a$b		b	a$b	a$b
+^		&	abc	@abc
+$		&	abc	@
+^$		&	""	@
+$^		-	""	@
+\($\)\(^\)	b	""	@
+# stop retching, those are legitimate (although disgusting)
+^^		-	""	@
+$$		-	""	@
+b$		&	abNc
+b$		&n	abNc	b
+^b$		&	aNbNc
+^b$		&n	aNbNc	b
+^$		&n	aNNb	@Nb
+^$		n	abc
+^$		n	abcN	@
+$^		n	aNNb	@Nb
+\($\)\(^\)	bn	aNNb	@Nb
+^^		n^	aNNb	@Nb
+$$		n	aNNb	@NN
+^a		^	a
+a$		$	a
+^a		^n	aNb
+^b		^n	aNb	b
+a$		$n	bNa
+b$		$n	bNa	b
+a*(^b$)c*	-	b	b
+a*\(^b$\)c*	b	b	b
+
+# certain syntax errors and non-errors
+|		C	EMPTY
+|		b	|	|
+*		C	BADRPT
+*		b	*	*
++		C	BADRPT
+?		C	BADRPT
+""		&C	EMPTY
+()		-	abc	@abc
+\(\)		b	abc	@abc
+a||b		C	EMPTY
+|ab		C	EMPTY
+ab|		C	EMPTY
+(|a)b		C	EMPTY
+(a|)b		C	EMPTY
+(*a)		C	BADRPT
+(+a)		C	BADRPT
+(?a)		C	BADRPT
+({1}a)		C	BADRPT
+\(\{1\}a\)	bC	BADRPT
+(a|*b)		C	BADRPT
+(a|+b)		C	BADRPT
+(a|?b)		C	BADRPT
+(a|{1}b)	C	BADRPT
+^*		C	BADRPT
+^*		b	*	*
+^+		C	BADRPT
+^?		C	BADRPT
+^{1}		C	BADRPT
+^\{1\}		bC	BADRPT
+
+# metacharacters, backslashes
+a.c		&	abc	abc
+a[bc]d		&	abd	abd
+a\*c		&	a*c	a*c
+a\\b		&	a\b	a\b
+a\\\*b		&	a\*b	a\*b
+a\bc		&	abc	abc
+a\		&C	EESCAPE
+a\\bc		&	a\bc	a\bc
+\{		bC	BADRPT
+a\[b		&	a[b	a[b
+a[b		&C	EBRACK
+# trailing $ is a peculiar special case for the BRE code
+a$		&	a	a
+a$		&	a$
+a\$		&	a
+a\$		&	a$	a$
+a\\$		&	a
+a\\$		&	a$
+a\\$		&	a\$
+a\\$		&	a\	a\
+
+# back references, ugh
+a\(b\)\2c	bC	ESUBREG
+a\(b\1\)c	bC	ESUBREG
+a\(b*\)c\1d	b	abbcbbd	abbcbbd	bb
+a\(b*\)c\1d	b	abbcbd
+a\(b*\)c\1d	b	abbcbbbd
+^\(.\)\1	b	abc
+a\([bc]\)\1d	b	abcdabbd	abbd	b
+a\(\([bc]\)\2\)*d	b	abbccd	abbccd
+a\(\([bc]\)\2\)*d	b	abbcbd
+# actually, this next one probably ought to fail, but the spec is unclear
+a\(\(b\)*\2\)*d		b	abbbd	abbbd
+# here is a case that no NFA implementation does right
+\(ab*\)[ab]*\1	b	ababaaa	ababaaa	a
+# check out normal matching in the presence of back refs
+\(a\)\1bcd	b	aabcd	aabcd
+\(a\)\1bc*d	b	aabcd	aabcd
+\(a\)\1bc*d	b	aabd	aabd
+\(a\)\1bc*d	b	aabcccd	aabcccd
+\(a\)\1bc*[ce]d	b	aabcccd	aabcccd
+^\(a\)\1b\(c\)*cd$	b	aabcccd	aabcccd
+
+# ordinary repetitions
+ab*c		&	abc	abc
+ab+c		-	abc	abc
+ab?c		-	abc	abc
+a\(*\)b		b	a*b	a*b
+a\(**\)b	b	ab	ab
+a\(***\)b	bC	BADRPT
+*a		b	*a	*a
+**a		b	a	a
+***a		bC	BADRPT
+
+# the dreaded bounded repetitions
+{		&	{	{
+{abc		&	{abc	{abc
+{1		C	BADRPT
+{1}		C	BADRPT
+a{b		&	a{b	a{b
+a{1}b		-	ab	ab
+a\{1\}b		b	ab	ab
+a{1,}b		-	ab	ab
+a\{1,\}b	b	ab	ab
+a{1,2}b		-	aab	aab
+a\{1,2\}b	b	aab	aab
+a{1		C	EBRACE
+a\{1		bC	EBRACE
+a{1a		C	EBRACE
+a\{1a		bC	EBRACE
+a{1a}		C	BADBR
+a\{1a\}		bC	BADBR
+a{,2}		-	a{,2}	a{,2}
+a\{,2\}		bC	BADBR
+a{,}		-	a{,}	a{,}
+a\{,\}		bC	BADBR
+a{1,x}		C	BADBR
+a\{1,x\}	bC	BADBR
+a{1,x		C	EBRACE
+a\{1,x		bC	EBRACE
+a{300}		C	BADBR
+a\{300\}	bC	BADBR
+a{1,0}		C	BADBR
+a\{1,0\}	bC	BADBR
+ab{0,0}c	-	abcac	ac
+ab\{0,0\}c	b	abcac	ac
+ab{0,1}c	-	abcac	abc
+ab\{0,1\}c	b	abcac	abc
+ab{0,3}c	-	abbcac	abbc
+ab\{0,3\}c	b	abbcac	abbc
+ab{1,1}c	-	acabc	abc
+ab\{1,1\}c	b	acabc	abc
+ab{1,3}c	-	acabc	abc
+ab\{1,3\}c	b	acabc	abc
+ab{2,2}c	-	abcabbc	abbc
+ab\{2,2\}c	b	abcabbc	abbc
+ab{2,4}c	-	abcabbc	abbc
+ab\{2,4\}c	b	abcabbc	abbc
+((a{1,10}){1,10}){1,10}	-	a	a	a,a
+
+# multiple repetitions
+a**		&C	BADRPT
+a++		C	BADRPT
+a??		C	BADRPT
+a*+		C	BADRPT
+a*?		C	BADRPT
+a+*		C	BADRPT
+a+?		C	BADRPT
+a?*		C	BADRPT
+a?+		C	BADRPT
+a{1}{1}		C	BADRPT
+a*{1}		C	BADRPT
+a+{1}		C	BADRPT
+a?{1}		C	BADRPT
+a{1}*		C	BADRPT
+a{1}+		C	BADRPT
+a{1}?		C	BADRPT
+a*{b}		-	a{b}	a{b}
+a\{1\}\{1\}	bC	BADRPT
+a*\{1\}		bC	BADRPT
+a\{1\}*		bC	BADRPT
+
+# brackets, and numerous perversions thereof
+a[b]c		&	abc	abc
+a[ab]c		&	abc	abc
+a[^ab]c		&	adc	adc
+a[]b]c		&	a]c	a]c
+a[[b]c		&	a[c	a[c
+a[-b]c		&	a-c	a-c
+a[^]b]c		&	adc	adc
+a[^-b]c		&	adc	adc
+a[b-]c		&	a-c	a-c
+a[b		&C	EBRACK
+a[]		&C	EBRACK
+a[1-3]c		&	a2c	a2c
+a[3-1]c		&C	ERANGE
+a[1-3-5]c	&C	ERANGE
+a[[.-.]--]c	&	a-c	a-c
+a[1-		&C	ERANGE
+a[[.		&C	EBRACK
+a[[.x		&C	EBRACK
+a[[.x.		&C	EBRACK
+a[[.x.]		&C	EBRACK
+a[[.x.]]	&	ax	ax
+a[[.x,.]]	&C	ECOLLATE
+a[[.one.]]b	&	a1b	a1b
+a[[.notdef.]]b	&C	ECOLLATE
+a[[.].]]b	&	a]b	a]b
+a[[:alpha:]]c	&	abc	abc
+a[[:notdef:]]c	&C	ECTYPE
+a[[:		&C	EBRACK
+a[[:alpha	&C	EBRACK
+a[[:alpha:]	&C	EBRACK
+a[[:alpha,:]	&C	ECTYPE
+a[[:]:]]b	&C	ECTYPE
+a[[:-:]]b	&C	ECTYPE
+a[[:alph:]]	&C	ECTYPE
+a[[:alphabet:]]	&C	ECTYPE
+[[:alnum:]]+	-	-%@a0X-	a0X
+[[:alpha:]]+	-	-%@aX0-	aX
+[[:blank:]]+	-	aSSTb	SST
+[[:cntrl:]]+	-	aNTb	NT
+[[:digit:]]+	-	a019b	019
+[[:graph:]]+	-	Sa%bS	a%b
+[[:lower:]]+	-	AabC	ab
+[[:print:]]+	-	NaSbN	aSb
+[[:punct:]]+	-	S%-&T	%-&
+[[:space:]]+	-	aSNTb	SNT
+[[:upper:]]+	-	aBCd	BC
+[[:xdigit:]]+	-	p0f3Cq	0f3C
+a[[=b=]]c	&	abc	abc
+a[[=		&C	EBRACK
+a[[=b		&C	EBRACK
+a[[=b=		&C	EBRACK
+a[[=b=]		&C	EBRACK
+a[[=b,=]]	&C	ECOLLATE
+a[[=one=]]b	&	a1b	a1b
+
+# complexities
+a(((b)))c	-	abc	abc
+a(b|(c))d	-	abd	abd
+a(b*|c)d	-	abbd	abbd
+# just gotta have one DFA-buster, of course
+a[ab]{20}	-	aaaaabaaaabaaaabaaaab	aaaaabaaaabaaaabaaaab
+# and an inline expansion in case somebody gets tricky
+a[ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab]	-	aaaaabaaaabaaaabaaaab	aaaaabaaaabaaaabaaaab
+# and in case somebody just slips in an NFA...
+a[ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab][ab](wee|week)(knights|night)	-	aaaaabaaaabaaaabaaaabweeknights	aaaaabaaaabaaaabaaaabweeknights
+# fish for anomalies as the number of states passes 32
+12345678901234567890123456789	-	a12345678901234567890123456789b	12345678901234567890123456789
+123456789012345678901234567890	-	a123456789012345678901234567890b	123456789012345678901234567890
+1234567890123456789012345678901	-	a1234567890123456789012345678901b	1234567890123456789012345678901
+12345678901234567890123456789012	-	a12345678901234567890123456789012b	12345678901234567890123456789012
+123456789012345678901234567890123	-	a123456789012345678901234567890123b	123456789012345678901234567890123
+# and one really big one, beyond any plausible word width
+1234567890123456789012345678901234567890123456789012345678901234567890	-	a1234567890123456789012345678901234567890123456789012345678901234567890b	1234567890123456789012345678901234567890123456789012345678901234567890
+# fish for problems as brackets go past 8
+[ab][cd][ef][gh][ij][kl][mn]	-	xacegikmoq	acegikm
+[ab][cd][ef][gh][ij][kl][mn][op]	-	xacegikmoq	acegikmo
+[ab][cd][ef][gh][ij][kl][mn][op][qr]	-	xacegikmoqy	acegikmoq
+[ab][cd][ef][gh][ij][kl][mn][op][q]	-	xacegikmoqy	acegikmoq
+
+# subtleties of matching
+abc		&	xabcy	abc
+a\(b\)?c\1d	b	acd
+aBc		i	Abc	Abc
+a[Bc]*d		i	abBCcd	abBCcd
+0[[:upper:]]1	&i	0a1	0a1
+0[[:lower:]]1	&i	0A1	0A1
+a[^b]c		&i	abc
+a[^b]c		&i	aBc
+a[^b]c		&i	adc	adc
+[a]b[c]		-	abc	abc
+[a]b[a]		-	aba	aba
+[abc]b[abc]	-	abc	abc
+[abc]b[abd]	-	abd	abd
+a(b?c)+d	-	accd	accd
+(wee|week)(knights|night)	-	weeknights	weeknights
+(we|wee|week|frob)(knights|night|day)	-	weeknights	weeknights
+a[bc]d		-	xyzaaabcaababdacd	abd
+a[ab]c		-	aaabc	abc
+abc		s	abc	abc
+a*		&	b	@b
+
+# Let's have some fun -- try to match a C comment.
+# first the obvious, which looks okay at first glance...
+/\*.*\*/	-	/*x*/	/*x*/
+# but...
+/\*.*\*/	-	/*x*/y/*z*/	/*x*/y/*z*/
+# okay, we must not match */ inside; try to do that...
+/\*([^*]|\*[^/])*\*/	-	/*x*/	/*x*/
+/\*([^*]|\*[^/])*\*/	-	/*x*/y/*z*/	/*x*/
+# but...
+/\*([^*]|\*[^/])*\*/	-	/*x**/y/*z*/	/*x**/y/*z*/
+# and a still fancier version, which does it right (I think)...
+/\*([^*]|\*+[^*/])*\*+/	-	/*x*/	/*x*/
+/\*([^*]|\*+[^*/])*\*+/	-	/*x*/y/*z*/	/*x*/
+/\*([^*]|\*+[^*/])*\*+/	-	/*x**/y/*z*/	/*x**/
+/\*([^*]|\*+[^*/])*\*+/	-	/*x****/y/*z*/	/*x****/
+/\*([^*]|\*+[^*/])*\*+/	-	/*x**x*/y/*z*/	/*x**x*/
+/\*([^*]|\*+[^*/])*\*+/	-	/*x***x/y/*z*/	/*x***x/y/*z*/
+
+# subexpressions
+.*		-	abc	abc	-
+a(b)(c)d	-	abcd	abcd	b,c
+a(((b)))c	-	abc	abc	b,b,b
+a(b|(c))d	-	abd	abd	b,-
+a(b*|c|e)d	-	abbd	abbd	bb
+a(b*|c|e)d	-	acd	acd	c
+a(b*|c|e)d	-	ad	ad	@d
+a(b?)c		-	abc	abc	b
+a(b?)c		-	ac	ac	@c
+a(b+)c		-	abc	abc	b
+a(b+)c		-	abbbc	abbbc	bbb
+a(b*)c		-	ac	ac	@c
+(a|ab)(bc([de]+)f|cde)	-	abcdef	abcdef	a,bcdef,de
+# the regression tester only asks for 9 subexpressions
+a(b)(c)(d)(e)(f)(g)(h)(i)(j)k	-	abcdefghijk	abcdefghijk	b,c,d,e,f,g,h,i,j
+a(b)(c)(d)(e)(f)(g)(h)(i)(j)(k)l	-	abcdefghijkl	abcdefghijkl	b,c,d,e,f,g,h,i,j,k
+a([bc]?)c	-	abc	abc	b
+a([bc]?)c	-	ac	ac	@c
+a([bc]+)c	-	abc	abc	b
+a([bc]+)c	-	abcc	abcc	bc
+a([bc]+)bc	-	abcbc	abcbc	bc
+a(bb+|b)b	-	abb	abb	b
+a(bbb+|bb+|b)b	-	abb	abb	b
+a(bbb+|bb+|b)b	-	abbb	abbb	bb
+a(bbb+|bb+|b)bb	-	abbb	abbb	b
+(.*).*		-	abcdef	abcdef	abcdef
+(a*)*		-	bc	@b	@b
+
+# do we get the right subexpression when it is used more than once?
+a(b|c)*d	-	ad	ad	-
+a(b|c)*d	-	abcd	abcd	c
+a(b|c)+d	-	abd	abd	b
+a(b|c)+d	-	abcd	abcd	c
+a(b|c?)+d	-	ad	ad	@d
+a(b|c?)+d	-	abcd	abcd	@d
+a(b|c){0,0}d	-	ad	ad	-
+a(b|c){0,1}d	-	ad	ad	-
+a(b|c){0,1}d	-	abd	abd	b
+a(b|c){0,2}d	-	ad	ad	-
+a(b|c){0,2}d	-	abcd	abcd	c
+a(b|c){0,}d	-	ad	ad	-
+a(b|c){0,}d	-	abcd	abcd	c
+a(b|c){1,1}d	-	abd	abd	b
+a(b|c){1,1}d	-	acd	acd	c
+a(b|c){1,2}d	-	abd	abd	b
+a(b|c){1,2}d	-	abcd	abcd	c
+a(b|c){1,}d	-	abd	abd	b
+a(b|c){1,}d	-	abcd	abcd	c
+a(b|c){2,2}d	-	acbd	acbd	b
+a(b|c){2,2}d	-	abcd	abcd	c
+a(b|c){2,4}d	-	abcd	abcd	c
+a(b|c){2,4}d	-	abcbd	abcbd	b
+a(b|c){2,4}d	-	abcbcd	abcbcd	c
+a(b|c){2,}d	-	abcd	abcd	c
+a(b|c){2,}d	-	abcbd	abcbd	b
+a(b+|((c)*))+d	-	abd	abd	@d,@d,-
+a(b+|((c)*))+d	-	abcd	abcd	@d,@d,-
+
+# check out the STARTEND option
+[abc]		&#	a(b)c	b
+[abc]		&#	a(d)c
+[abc]		&#	a(bc)d	b
+[abc]		&#	a(dc)d	c
+.		&#	a()c
+b.*c		&#	b(bc)c	bc
+b.*		&#	b(bc)c	bc
+.*c		&#	b(bc)c	bc
+
+# plain strings, with the NOSPEC flag
+abc		m	abc	abc
+abc		m	xabcy	abc
+abc		m	xyz
+a*b		m	aba*b	a*b
+a*b		m	ab
+""		mC	EMPTY
+
+# cases involving NULs
+aZb		&	a	a
+aZb		&p	a
+aZb		&p#	(aZb)	aZb
+aZ*b		&p#	(ab)	ab
+a.b		&#	(aZb)	aZb
+a.*		&#	(aZb)c	aZb
+
+# word boundaries (ick)
+[[:<:]]a	&	a	a
+[[:<:]]a	&	ba
+[[:<:]]a	&	-a	a
+a[[:>:]]	&	a	a
+a[[:>:]]	&	ab
+a[[:>:]]	&	a-	a
+[[:<:]]a.c[[:>:]]	&	axcd-dayc-dazce-abc	abc
+[[:<:]]a.c[[:>:]]	&	axcd-dayc-dazce-abc-q	abc
+[[:<:]]a.c[[:>:]]	&	axc-dayc-dazce-abc	axc
+[[:<:]]b.c[[:>:]]	&	a_bxc-byc_d-bzc-q	bzc
+[[:<:]].x..[[:>:]]	&	y_xa_-_xb_y-_xc_-axdc	_xc_
+[[:<:]]a_b[[:>:]]	&	x_a_b
+
+# past problems, and suspected problems
+(A[1])|(A[2])|(A[3])|(A[4])|(A[5])|(A[6])|(A[7])|(A[8])|(A[9])|(A[A])	-	A1	A1
+abcdefghijklmnop	i	abcdefghijklmnop	abcdefghijklmnop
+abcdefghijklmnopqrstuv	i	abcdefghijklmnopqrstuv	abcdefghijklmnopqrstuv
+(ALAK)|(ALT[AB])|(CC[123]1)|(CM[123]1)|(GAMC)|(LC[23][EO ])|(SEM[1234])|(SL[ES][12])|(SLWW)|(SLF )|(SLDT)|(VWH[12])|(WH[34][EW])|(WP1[ESN])	-	CC11	CC11
+CC[13]1|a{21}[23][EO][123][Es][12]a{15}aa[34][EW]aaaaaaa[X]a	-	CC11	CC11
+Char \([a-z0-9_]*\)\[.*	b	Char xyz[k	Char xyz[k	xyz
+a?b	-	ab	ab
+-\{0,1\}[0-9]*$	b	-5	-5
+a*a*a*a*a*a*a*	&	aaaaaa	aaaaaa
diff --git a/regex/utils.h b/regex/utils.h
new file mode 100644
index 0000000..1a997ac
--- /dev/null
+++ b/regex/utils.h
@@ -0,0 +1,22 @@
+/* utility definitions */
+#ifdef _POSIX2_RE_DUP_MAX
+#define	DUPMAX	_POSIX2_RE_DUP_MAX
+#else
+#define	DUPMAX	255
+#endif
+#define	INFINITY	(DUPMAX + 1)
+#define	NC		(CHAR_MAX - CHAR_MIN + 1)
+typedef unsigned char uch;
+
+/* switch off assertions (if not already off) if no REDEBUG */
+#ifndef REDEBUG
+#ifndef NDEBUG
+#define	NDEBUG	/* no assertions please */
+#endif
+#endif
+#include <assert.h>
+
+/* for old systems with bcopy() but no memmove() */
+#ifdef USEBCOPY
+#define	memmove(d, s, c)	bcopy(s, d, c)
+#endif
diff --git a/test.html b/test.html
new file mode 100644
index 0000000..09865dc
--- /dev/null
+++ b/test.html
@@ -0,0 +1,11 @@
+<html>
+<head>
+	<title>GrokHtml Test Document</title>
+</head>
+<body>
+	<table>
+	<tr><td>foo = baz</td></tr>
+	<tr><td>bar = quux</td></tr>
+	</table>
+</body>
+</html>
\ No newline at end of file
diff --git a/treexpr.c b/treexpr.c
new file mode 100644
index 0000000..eb68f2e
--- /dev/null
+++ b/treexpr.c
@@ -0,0 +1,1145 @@
+/* treexpr.c - Tree expression language source file
+ + Copyright (C) 2005 Dell, Inc.
+ + Authors: David Barksdale <amatus@ocgnet.org>
+ +
+ +  This library is free software; you can redistribute it and/or
+ +  modify it under the terms of the GNU Lesser General Public
+ +  License as published by the Free Software Foundation; either
+ +  version 2.1 of the License, or (at your option) any later version.
+ +
+ +  This library is distributed in the hope that it will be useful,
+ +  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ +  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ +  Lesser General Public License for more details.
+ +
+ +  You should have received a copy of the GNU Lesser General Public
+ +  License along with this library; if not, write to the Free Software
+ +  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+-- Syntax --
+ Expr   ::= Term | Expr "|" Term
+ Term   ::= Factor | Term Factor
+ Factor ::= Symbol | Symbol "*" | "~" | "(" Expr ")" | "(" Expr ")" "*"
+			| Symbol "->" Expr | Symbol ":" String | Symbol Attrs | Symbol Attrs "->" Expr
+ Attrs  ::= "<" Attr* ">"
+ Attr   ::= Symbol | Symbol "=" String
+ Symbol ::= any alphanumeric string with '_' and '-'
+ String ::= quoted string (skips over \")
+
+-- Semantics --
+A tree can be thought of as a hierarchical list, each element of the list can have a list of
+children. Consider the following tree:
+
+    html
+    /   \
+ head   body
+  /      / \
+title   h1  p 
+
+root list: html
+list of html's children: head body
+list of head's children: title
+list of body's children: h1 p
+list of h1's chlidren: ~ (where ~ denotes the empty list)
+list of p's children: ~
+
+By the same token, a tree expression can be thought of as a hierarchical regular expression,
+each symbol in the expression can have a child expression. The "->" operator binds a child
+expression to a symbol in the parent expression. If a symbol has no child expression it is
+equivalent to having a child expression that matches everything. In other words the children
+of a symbol are ignored if there is no child expression. It can also be said that "->" adds
+a restriction to the symbol on it's left-hand side: the symbol will only be matched if the
+symbol's children match the child expression. Other restriction operators are discussed later to
+improve matching of HTML. Consider the following expressions:
+
+  These match the tree above:
+	html					- matches the root list and ignores html's children
+	html -> head body		- also matches html's children and ignores head and body's children
+	html -> (head -> title) body	- also matches head's children and ignores title's children
+	html -> (head -> title -> ~) body							- also matches title's children
+	html -> (head -> title -> ~) (body -> h1 p)					- also matches body's children
+	html -> (head -> title -> ~) (body -> (h1 -> ~) (p -> ~))	- matches the tree exactly
+
+  These do not match the tree above:
+	body				- does not match root list
+	html -> body		- matches root list but does not match html's children (must match all)
+	html -> body head	- matches root list but html's children are out of order
+
+Note the grouping around "->". In the second expression "->" binds the symbol "html" to the
+expression "head body". In the third expression we want the symbol "head" to be bound to the
+expression "title" and not "title body" so we must group them together using parenthesis.
+
+Tree expressions use the alternation "|" and closure "*" operators from reqular expressions.
+Consider the following expressions:
+	html*	- matches the root list because it consists of zero or more "html" symbols
+	html | xml	- matches the root list because it consists of "html" or "xml"
+	html -> (head -> title | title meta) body	- matches
+
+In addition to the "~" special symbol there is "." which matches any symbol:
+	html -> .*		- matches the root list and html's children because html has zero or more
+	html -> .* (body -> .* p .*) .*		- matches a tree that has "html" at the root, html has
+										  atleast one child named "body", and body has atleast
+										  one child named "p".
+
+-- Extra restriction operators for HTML matching --
+
+The ":" operator binds a regular expression to a symbol, the symbol matches only if it's
+contents matches the regular expression. In HTML the only tags that have contents are "text"
+and "comment". So most of the time it will be used like:
+	p -> text:"ab*c"	- matches the HTML '<p>abbbbbc</p>'
+
+The "<", "=", and ">" operators are used together to bind a symbol to an attribute list,
+the symbol matches only if every attribute matches an attribute of the HTML tag. An attribute
+restriction is a list of name and value pairs. A name without a value is matched only if it
+appears in the HTML without a value. Consider the following:
+	table <bgcolor="blue">	- matches the HTML '<table bgcolor="blue">'
+						  and also the HTML '<table bgcolor="blue" border="1">'
+	foo <bar>			- matches the HTML '<foo bar>' but not '<foo bar="">' or '<foo bar="baz">'
+	foo <bar> | foo <bar=".*">	- matches all three
+
+It is possible to combine the attribute restriction operators with the "->" operator (for example
+option <selected> -> text:"blue"), but it is not possible to combine the content restriction
+operator with the "->" operator (for example text:"blue" -> br) because "text" and "comment"
+symbols never have children.
+
+-- Extracting values from an HTML page --
+This section has been up for debate because it can be very confusing. The way we extract strings
+from the tree expressions is from the contents and attribute rescrictions. These restrictions
+contain regular expressions that match against some of the data contained in an HTML page. Most
+regular expression libraries allow you to use something called back references where each
+parenthasized sub-expression is given a number and the string matching that sub-expression can be
+referenced later. For example the expression "foo" has no sub-expressions, the expression "fo(o*)"
+has one sub-expression, namely "o*". When "fo(o*)" is matched against "fooo", the fist
+sub-expression references the string "oo". The sub-expressions are numbered by the position of
+their open parenthesis. For example "(b(a)(r))" has three sub-expressions, 1. "b(a)(r)" 2. "a"
+3. "r". If a sub-expression matches multiple strings then the last match is what is referenced.
+For example "(ab|ac)*" matches "ababac" and the string referenced will be "ac".
+
+A tree expression can have several regular expressions embedded in it. In order to find a specific
+sub-expression they are numbered in the order they appear in the tree expression. For example:
+	form -> input<value="([0-9]+)"> text:"."
+	        input<value="([0-9]+)"> text:"."
+			input<value="([0-9]+)"> text:"."
+			input<value="([0-9]+)"> input
+has four sub-expressions. This tree expression would match against an HTML form that might be used
+for changing an IP address:
+<form method="POST" action="/cgi-bin/setip">
+	<input type="text" name="first" value="192"> .
+	<input type="text" name="second" value="168"> .
+	<input type="text" name="third" value="1"> .
+	<input type="text" name="fourth" value="42"> <input type="submit" value="Set IP">
+</form>
+In this case the extracted values will be:
+1: "192"
+2: "168"
+3: "1"
+4: "42"
+It's simple to specify a method for combining the strings together to form a usefull output.
+For example something like "\1.\2.\3.\4" would produce "192.168.1.42".
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <libxml/tree.h>
+#include <sys/types.h>
+#include "regex.h"
+#include "treexpr.h"
+
+#ifdef _WINDOWS
+#define strcasecmp stricmp
+#endif
+
+// allocator that never returns NULL, cheap hack to make code shorter
+void *zalloc( size_t size )
+{
+	void *p;
+
+	do { p = calloc( size, 1 );
+	} while( p == NULL );
+	return p;
+}
+
+// builds a machine that matches a symbol
+struct machine *symbol( char *name )
+{
+	struct machine *m;
+	struct state *start, *final;
+	struct trans *tr;
+
+	// alloc stuff
+	m = zalloc( sizeof( struct machine ));
+	start = zalloc( sizeof( struct state ));
+	final = zalloc( sizeof( struct state ));
+	tr = zalloc( sizeof( struct trans ));
+
+	// insert transition
+	tr->name = name;
+	tr->st = final;
+	start->tr = tr;
+
+	// maintain linked list
+	start->next = final;
+
+	// finish machine
+	m->start = start;
+	m->final = final;
+	return m;
+}
+
+// builds a machine that matches the empty string
+struct machine *epsilon( void )
+{
+	struct machine *m;
+	struct state *start, *final;
+	struct epsilon *cat;
+
+	// alloc stuff
+	m = zalloc( sizeof( struct machine ));
+	start = zalloc( sizeof( struct state ));
+	final = zalloc( sizeof( struct state ));
+	cat = zalloc( sizeof( struct epsilon ));
+
+	// insert epsilon transition
+	cat->st = final;
+	start->ep = cat;
+
+	// maintain liked list
+	start->next = final;
+
+	// finish machine
+	m->start = start;
+	m->final = final;
+	return m;
+}
+
+// builds a machine that matches nothing (not used at present, but here for completeness)
+struct machine *null( void )
+{
+	struct machine *m;
+	struct state *start, *final;
+
+	// alloc stuff
+	m = zalloc( sizeof( struct machine ));
+	start = zalloc( sizeof( struct state ));
+	final = zalloc( sizeof( struct state ));
+
+	// maintain linked list
+	start->next = final;
+
+	// finish machine
+	m->start = start;
+	m->final = final;
+	return m;
+}
+
+// concatanates two machines
+struct machine *concat( struct machine *a, struct machine *b )
+{
+	struct epsilon *cat;
+
+	if( a == NULL || b == NULL )
+		return NULL;
+
+	// alloc stuff
+	cat = zalloc( sizeof( struct epsilon ));
+
+	// insert epsilon transition
+	cat->st = b->start;
+	cat->next = a->final->ep;
+	a->final->ep = cat;
+
+	// maintain linked list
+	a->final->next = b->start;
+
+	// use machine 'a' as our new machine and free 'b'
+	a->final = b->final;
+	free( b );
+	return a;
+}
+
+// alternates two machines (spike)
+struct machine *alternate( struct machine *a, struct machine *b )
+{
+	struct state *start, *final;
+	struct epsilon *s1, *s2, *f1, *f2;
+
+	if( a == NULL || b == NULL )
+		return NULL;
+
+	// alloc stuff
+	start = zalloc( sizeof( struct state ));
+	final = zalloc( sizeof( struct state ));
+	s1 = zalloc( sizeof( struct epsilon ));
+	s2 = zalloc( sizeof( struct epsilon ));
+	f1 = zalloc( sizeof( struct epsilon ));
+	f2 = zalloc( sizeof( struct epsilon ));
+
+	// insert epsilon transitions from our new start state
+	// to the start states of the two machines
+	s1->st = a->start;
+	s2->st = b->start;
+	s1->next = s2;
+	start->ep = s1;
+
+	// insert epsilon transitions from the final states of the
+	// new machines to our new final state
+	f1->st = final;
+	f2->st = final;
+	f1->next = a->final->ep;
+	a->final->ep = f1;
+	f2->next = b->final->ep;
+	b->final->ep = f2;
+
+	// maintain linked list
+	start->next = a->start;
+	a->final->next = b->start;
+	b->final->next = final;
+
+	// use machine 'a' as our new machine and free 'b'
+	a->start = start;
+	a->final = final;
+	free( b );
+	return a;
+}
+
+// creates the closure of a machine (splat)
+struct machine *closure( struct machine *a )
+{
+	struct state *start, *final;
+	struct epsilon *s1, *s2, *f1, *f2;
+
+	if( a == NULL )
+		return NULL;
+
+	// alloc stuff
+	start = zalloc( sizeof( struct state ));
+	final = zalloc( sizeof( struct state ));
+	s1 = zalloc( sizeof( struct epsilon ));
+	s2 = zalloc( sizeof( struct epsilon ));
+	f1 = zalloc( sizeof( struct epsilon ));
+	f2 = zalloc( sizeof( struct epsilon ));
+
+	// insert epsilon transitions from our new start state to
+	// the machine's start state and to our new final state
+	s1->st = final;
+	s2->st = a->start;
+	s1->next = s2;
+	start->ep = s1;
+
+	// insert epsilon transitions from the machine's final state
+	// to the machine's start state and our new final state
+	f1->st = a->start;
+	f2->st = final;
+	f1->next = f2;
+	f2->next = a->final->ep;
+	a->final->ep = f1;
+
+	// maintain linked list
+	start->next = a->start;
+	a->final->next = final;
+
+	// use 'a' as our new machine
+	a->start = start;
+	a->final = final;
+	return a;
+}
+
+void free_machine( struct machine *m );
+
+// free each state in a linked list
+void free_states( struct state *sl )
+{
+	struct trans *tr;
+	struct epsilon *ep, *epn;
+	struct state *next;
+	struct attribute *at, *atn;
+
+	for( ; sl != NULL; sl = next )
+	{
+		next = sl->next;
+
+		// free each transition off this state
+		tr = sl->tr;
+		if( tr != NULL )
+		{
+			// free all the junk that can hang off of a transition
+			free_machine( tr->ptr );
+			free( tr->name );
+			if( tr->re.re_magic != 0 )
+				notbuiltin_regfree( &tr->re );
+			for( at = tr->attrs; at != NULL; at = atn )
+			{
+				atn = at->next;
+				free( at->name );
+				if( at->re.re_magic != 0 )
+					notbuiltin_regfree( &at->re );
+				free( at );
+			}
+			free( tr );
+		}
+
+		// free each epsilon transition (easy)
+		for( ep = sl->ep; ep != NULL; ep = epn )
+		{
+			epn = ep->next;
+			free( ep );
+		}
+
+		// finally free the state
+		free( sl );
+	}
+}
+
+void free_machine( struct machine *m )
+{
+	int i;
+
+	if( m == NULL )
+		return;
+
+	// free every state in the machine
+	free_states( m->start );
+
+	// if we have an E function free it
+	if( m->E != NULL )
+	{
+		for( i = 0; i < m->states; i++ )
+			free( m->E[i] );
+		free( m->E );
+	}
+
+	// free bitmasks
+	if( m->cur_state != NULL )
+		free( m->cur_state );
+	if( m->next_state != NULL )
+		free( m->next_state );
+
+	// finally free the machine
+	free( m );
+}
+
+/*
+ * Tokenizer
+ */
+struct token
+{
+	int t;
+	char *name;
+};
+
+#define T_EOL			( -2 ) // not really paid attention to
+#define T_ERROR			( -1 ) // tokenizing error, look at token->error and token->buf
+#define T_SYMBOL		(  0 ) // symbol
+#define T_SQUIGGLE		(  1 ) // ~
+#define T_WAX			(  2 ) // (
+#define T_WANE			(  3 ) // )
+#define T_SPIKE			(  4 ) // |
+#define T_SPLAT			(  5 ) // *
+#define T_PTR			(  6 ) // ->
+#define T_TWOSPOT		(  7 ) // :
+#define T_ANGLE			(  8 ) // <
+#define T_RIGHTANGLE	(  9 ) // >
+#define T_HALFMESH		( 10 ) // =
+#define T_STRING		( 11 ) // quoted string
+
+// parse the next token in a string and return a pointer into the string were we stoped
+const char *get_tok( const char *str, struct token *tk )
+{
+	static char *name;
+	const char *p;
+	int i, len = 0;
+
+	if( str == NULL )
+	{
+		tk->t = T_ERROR;
+		return NULL;
+	}
+
+	// skip whitespace
+	for( p = str; *p != 0 && isspace( *p ); p++ );
+
+	switch( *p )
+	{
+	case 0:
+		tk->t = T_EOL;
+		return p;
+	case '~':
+		tk->t = T_SQUIGGLE;
+		return p + 1;
+	case '(':
+		tk->t = T_WAX;
+		return p + 1;
+	case ')':
+		tk->t = T_WANE;
+		return p + 1;
+	case '|':
+		tk->t = T_SPIKE;
+		return p + 1;
+	case '*':
+		tk->t = T_SPLAT;
+		return p + 1;
+	case '-':
+		if( p[1] == '>' )
+		{
+			tk->t = T_PTR;
+			return p + 2;
+		}
+		tk->t = T_ERROR;
+		return p;
+	case ':':
+		tk->t = T_TWOSPOT;
+		return p + 1;
+	case '<':
+		tk->t = T_ANGLE;
+		return p + 1;
+	case '>':
+		tk->t = T_RIGHTANGLE;
+		return p + 1;
+	case '=':
+		tk->t = T_HALFMESH;
+		return p + 1;
+	case '\"':
+		p++;
+		len = 16;
+		name = zalloc( len );
+		for( i = 0; p[i] != 0 && p[i] != '\"'; i++ )
+		{
+			if( i + 1 >= len )
+				name = realloc( name, len *= 2 );
+			if( p[i] == '\\' && p[i + 1] == '\"' && i < 254 )
+			{
+				name[i] = p[i];
+				i++;
+			}
+			name[i] = p[i];
+		}
+		name[i] = 0;
+		tk->t = p[i] == 0 ? T_ERROR : T_STRING;
+		tk->name = name;
+		return p + i + ( p[i] == '\"' ? 1 : 0 );
+	case '.':
+		name = zalloc( 2 );
+		name[0] = '.';
+		name[1] = 0;
+		tk->t = T_SYMBOL;
+		tk->name = name;
+		return p + 1;
+	default:
+		len = 16;
+		name = zalloc( len );
+		for( i = 0; isalnum( p[i] ) || p[i] == '_' || p[i] == '-'; i++ )
+		{
+			if( i + 1 >= len )
+				name = realloc( name, len *= 2 );
+			name[i] = p[i];
+		}
+		name[i] = 0;
+		tk->t = i > 0 ? T_SYMBOL : T_ERROR;
+		tk->name = name;
+		return p + i;
+	}
+}
+
+const char *parse_treexpr( const char *expr, struct machine **m );
+
+// parses an attribute construction: <foo="bar" baz="quux" quuux>
+// the opening angle has already been consumed
+const char *parse_attrs( const char *expr, struct attribute **a )
+{
+	struct token tk;
+	struct attribute *prev = NULL, *attr;
+	const char *next;
+
+	// build a list of attributes in order
+	for( next = get_tok( expr, &tk ); tk.t == T_SYMBOL; )
+	{
+		// fist we grab the name
+		attr = zalloc( sizeof( struct attribute ));
+		if( prev == NULL )
+			prev = *a = attr;
+		else
+			prev = prev->next = attr;
+		attr->name = tk.name;
+
+		// check for optional =
+		next = get_tok( next, &tk );
+		if( tk.t != T_HALFMESH )
+			continue;
+
+		// grab regex and compile it
+		next = get_tok( next, &tk );
+		if( tk.t != T_STRING )
+			return NULL;
+		if( notbuiltin_regcomp( &attr->re, tk.name, REG_EXTENDED
+			| REG_ICASE ) != 0 )
+		{
+			notbuiltin_regfree( &attr->re );
+			attr->re.re_magic = 0;
+			return NULL;
+		}
+		free( tk.name );
+		next = get_tok( next, &tk );
+	}
+	if( tk.t == T_RIGHTANGLE )
+		return next;
+	return NULL;
+}
+
+// parse a tree expression "factor"
+// a factor is what I'm calling the operands to concatenation
+// so it's either a symbol (with optional restrictions), a parenthasized expression
+// or a factor with a *
+// this does not allow foolishness like "foo**" (equivalent to "foo*") or "~*" (equivalent to "~")
+// even though they are technically valid
+const char *parse_factor( const char *expr, struct machine **m )
+{
+	struct token tk;
+	struct machine *r;
+	const char *next, *cur;
+
+	// this token should either be a symbol, a ~, or a (
+	cur = get_tok( expr, &tk );
+	if( tk.t == T_ERROR )
+	{
+		*m = zalloc( sizeof( struct machine ));
+		( *m )->error = "Tokenizing error";
+		( *m )->buf = expr;
+		return NULL;
+	}
+	if( tk.t == T_SYMBOL )
+	{
+		// build a machine to match the symbol
+		*m = symbol( tk.name );
+		next = get_tok( cur, &tk );
+		if( tk.t == T_ERROR )
+		{
+			( *m )->error = "Tokenizing error";
+			( *m )->buf = cur;
+			return NULL;
+		}
+
+		// if there's a * build the closure
+		if( tk.t == T_SPLAT )
+		{
+			*m = closure( *m );
+			return next;
+		}
+
+		// if there's a -> then parse the expression on the rhs and add it as a restriction
+		if( tk.t == T_PTR )
+		{
+			next = parse_treexpr( next, &r );
+			( *m )->start->tr->ptr = r;
+			if( next == NULL )
+			{
+				( *m )->error = r->error;
+				( *m )->buf = r->buf;
+				return NULL;
+			}
+			return next;
+		}
+
+		// if there's a : then compile the regex and add it as a restriction
+		if( tk.t == T_TWOSPOT )
+		{
+			cur = next;
+			next = get_tok( cur, &tk );
+			if( tk.t == T_ERROR )
+			{
+				( *m )->error = "Tokenizing error";
+				( *m )->buf = cur;
+				return NULL;
+			}
+			if( tk.t != T_STRING )
+			{
+				( *m )->error = "Expecting a \"-delimited string";
+				( *m )->buf = cur;
+				return NULL;
+			}
+			if( notbuiltin_regcomp( &( *m )->start->tr->re, tk.name,
+				REG_EXTENDED | REG_ICASE ) != 0 )
+			{
+				notbuiltin_regfree( &( *m )->start->tr->re );
+				( *m )->start->tr->re.re_magic = 0;
+				( *m )->error = "Error parsing regular expression";
+				( *m )->buf = cur;
+			}
+			free( tk.name );
+			return next;
+		}
+
+		// if there's a < then parse attributes and add it as a restriction
+		if( tk.t == T_ANGLE )
+		{
+			next = parse_attrs( next, &( *m )->start->tr->attrs );
+			if( next == NULL )
+			{
+				( *m )->error = "Expecting attribute list, ie <name=\"value\" name2=\"value2\">";
+				( *m )->buf = cur;
+				return NULL;
+			}
+			cur = next;
+
+			// we also allow a -> restriction in this case
+			next = get_tok( cur, &tk );
+			if( tk.t == T_PTR )
+			{
+				next = parse_treexpr( next, &r );
+				( *m )->start->tr->ptr = r;
+				if( next == NULL )
+				{
+					( *m )->error = r->error;
+					( *m )->buf = r->buf;
+					return NULL;
+				}
+				return next;
+			}
+			return cur;
+		}
+		return cur;
+	}
+	if( tk.t == T_SQUIGGLE )
+	{
+		// build epsilon machine
+		*m = epsilon( );
+		return cur;
+	}
+	if( tk.t == T_WAX )
+	{
+		// parse expression
+		cur = parse_treexpr( cur, m );
+		if( cur == NULL )
+			return NULL;
+
+		// make sure we end in )
+		next = get_tok( cur, &tk );
+		if( tk.t == T_ERROR )
+		{
+			( *m )->error = "Tokenizing error";
+			( *m )->buf = cur;
+			return NULL;
+		}
+		if( tk.t != T_WANE )
+		{
+			( *m )->error = "Expected ')'";
+			( *m )->buf = cur;
+			return NULL;
+		}
+
+		// check for * and build closure
+		cur = next;
+		next = get_tok( cur, &tk );
+		if( tk.t == T_ERROR )
+		{
+			( *m )->error = "Tokenizing error";
+			( *m )->buf = cur;
+			return NULL;
+		}
+		if( tk.t == T_SPLAT )
+		{
+			*m = closure( *m );
+			return next;
+		}
+		return cur;
+	}
+
+	// invalid symbol
+	*m = zalloc( sizeof( struct machine ));
+	( *m )->error = "Expected symbol or '~' or '('";
+	( *m )->buf = expr;
+	return NULL;
+}
+
+// parse a tree expression "term"
+// a term is what I'm calling the operands to alternation
+// a term is either a factor, or a list of factors concatenated together
+const char *parse_term( const char *expr, struct machine **m )
+{
+	struct token tk;
+	struct machine *r;
+	const char *cur;
+
+	// grab the first factor
+	cur = parse_factor( expr, m );
+	if( cur == NULL )
+		return NULL;
+
+	// grab zero or more factors
+	for( get_tok( cur, &tk ); tk.t == T_SYMBOL || tk.t == T_WAX || tk.t == T_SQUIGGLE;
+		get_tok( cur, &tk ))
+	{
+		cur = parse_factor( cur, &r );
+		if( cur == NULL )
+		{
+			( *m )->error = r->error;
+			( *m )->buf = r->buf;
+			free_machine( r );
+			return NULL;
+		}
+
+		// concatenate the factors
+		*m = concat( *m, r );
+	}
+	if( tk.t == T_ERROR )
+	{
+		( *m )->error = "Tokenizing error";
+		( *m )->buf = cur;
+		return NULL;
+	}
+	return cur;
+}
+
+// parse a tree expression
+// an expression is just a term or a list of terms seperated by |
+// this looks almost exactly like parse_term()
+const char *parse_treexpr( const char *expr, struct machine **m )
+{
+	struct token tk;
+	const char *next, *cur;
+	struct machine *r;
+
+	// grab the first term
+	cur = parse_term( expr, m );
+	if( cur == NULL )
+		return NULL;
+
+	// grab zero or more terms
+	for( next = get_tok( cur, &tk ); tk.t == T_SPIKE; next = get_tok( cur, &tk ))
+	{
+		cur = parse_term( next, &r );
+		if( cur == NULL )
+		{
+			( *m )->error = r->error;
+			( *m )->buf = r->buf;
+			free_machine( r );
+			return NULL;
+		}
+
+		// combine the terms using alternation
+		*m = alternate( *m, r );
+	}
+	if( tk.t == T_ERROR )
+	{
+		( *m )->error = "Tokenizing error";
+		( *m )->buf = cur;
+		return NULL;
+	}
+	return cur;
+}
+
+
+// process a regex restriction (basically just executes the regex)
+int regex_process( struct trans *tr, char *content )
+{
+	if( content == NULL )
+		return 0;
+	if( notbuiltin_regexec( &tr->re, content, RESUBR, tr->match, 0 ) == 0 )
+	{
+		tr->str = content;
+		return 1;
+	}
+	tr->str = NULL;
+	return 0;
+}
+
+// process an attribute restriction
+// it's important that we don't save the matches for all regexes until we know all of them
+// match. otherwise if you were trying to match <foo="bar" bar="baz"> and you had a list like
+// <foo="bar" bar="baz">   (both regexes match)
+// <foo="barr" bar="quux"> (the first one matches and overwrites the previous match for foo)
+// then you would be left with foo="barr" bar="baz" as your matches
+int attrs_process( struct trans *tr, struct _xmlAttr *properties )
+{
+	struct attribute *attr;
+	struct _xmlAttr *cur;
+	regmatch_t match[RESUBR];
+
+	// first pass makes sure each attribute matches
+	for( attr = tr->attrs; attr != NULL; attr = attr->next )
+	{
+		for( cur = properties; cur != NULL; cur = cur->next )
+		{
+			if( strcasecmp( attr->name, (char *)cur->name ) == 0 )
+			{
+				// if there's no value it will only match if we didn't specify a regex
+				if( cur->children == NULL )
+				{
+					if( attr->re.re_magic == 0 )
+						break;
+					return 0;
+				}
+				// otherwise the regex has to match the value
+				if( notbuiltin_regexec( &attr->re,
+					(char *)cur->children->content, RESUBR,
+					match, 0 ) == 0 )
+					break;
+				else
+					attr->str = NULL;
+				return 0;
+			}
+		}
+		if( cur == NULL )
+			return 0;
+	}
+	// second pass saves the matches
+	for( attr = tr->attrs; attr != NULL; attr = attr->next )
+	{
+		for( cur = properties; cur != NULL; cur = cur->next )
+		{
+			if( strcasecmp( attr->name, (char *)cur->name ) == 0 )
+			{
+				// if there's no value it will only match if we didn't specify a regex
+				if( cur->children == NULL )
+				{
+					if( attr->re.re_magic == 0 )
+						break;
+					return 0;
+				}
+				// otherwise the regex has to match the value
+				if( notbuiltin_regexec( &attr->re,
+					(char *)cur->children->content, RESUBR,
+					attr->match, 0 ) == 0 )
+				{
+					attr->str = (char *)cur->children->content;
+					break;
+				}
+				else
+					attr->str = NULL;
+				return 0;
+			}
+		}
+		if( cur == NULL )
+			return 0;
+	}
+	return 1;
+}
+
+// some handy macros:
+// number of bits in type pointed to by x
+#define B( x )				(sizeof(*(x))*8)
+
+// number of elements in array pointed to by x in order to contain n bits
+#define N( x, n )			(((n)+B(x)-1)/B(x))
+
+// test bit b of array pointed to by x
+#define TEST_BIT( x, b )	(((x)[(b)/B(x)]>>((b)%B(x)))&1)
+
+// set bit b of array pointed to by x
+#define SET_BIT( x, b )		((x)[(b)/B(x)]|=1<<((b)%B(x)))
+
+// compute the disjunction of two bitfields of n bits
+#define OR( x, y, n )		{unsigned int _i;for(_i=0;_i<N(x,n);(x)[_i]|=(y)[_i],_i++);}
+
+// applies a machine to an xml tree
+// returns true iff the machine accepts
+// all matches to regexes are contained within the machine
+int tree_process( struct machine *m, xmlNodePtr node )
+{
+	int *e, done;
+	struct state *cur, *cur2;
+	struct trans *tr;
+	struct epsilon *ep;
+
+	if( m == NULL )
+		return 1;
+	if( m->E == NULL )
+	{
+		// Generate E function
+		// the E function is an array of bitmasks indexed by state number
+		// the bitmask represents the states you can reach by epsilon transitions
+
+		// number states
+		m->states = 0;
+		for( cur = m->start; cur != NULL; cur = cur->next )
+			cur->num = m->states++;
+
+		// fill E
+		m->E = zalloc( sizeof( *m->E ) * m->states );
+		for( cur = m->start; cur != NULL; cur = cur->next )
+		{
+			e = m->E[cur->num] = zalloc( N( *m->E, m->states ) * sizeof( **m->E ));
+
+			// we can reach ourself
+			SET_BIT( e, cur->num );
+
+			// try to add new states until an iteration of this loop makes no progress
+			done = 0;
+			while( !done )
+			{
+				done = 1;
+				// for each state that is already in the bitmask, add states you can reach
+				// by epsilon transitions
+				for( cur2 = m->start; cur2 != NULL; cur2 = cur2->next )
+					if( TEST_BIT( e, cur2->num ))
+						for( ep = cur2->ep; ep != NULL; ep = ep->next )
+							if( !TEST_BIT( e, ep->st->num ))
+							{
+								SET_BIT( e, ep->st->num );
+								done = 0;
+							}
+			}
+		}
+	}
+
+	// allocate current state and next state bitmasks
+	if( m->cur_state == NULL )
+		m->cur_state = zalloc( N( m->cur_state, m->states ) * sizeof( *m->cur_state ));
+	if( m->next_state == NULL )
+		m->next_state = zalloc( N( m->next_state, m->states ) * sizeof( *m->next_state ));
+
+	// our inital current state is E(start)
+	OR( m->cur_state, m->E[m->start->num], m->states );
+
+	// main loop, terminate when we run out of input or when there's no states in the cur_state bitmask
+	while( node != NULL )
+	{
+		unsigned int i;
+		int sum = 0;
+
+		// are we still alive?
+		for( i = 0; i < N( m->cur_state, m->states ); i++ )
+			sum |= m->cur_state[i];
+		if( sum == 0 ) break;
+
+		// zero out next_state and start adding states we can reach by normal transitions
+		memset( m->next_state, 0, N( m->next_state, m->states ) * sizeof( *m->next_state ));
+
+		// for each state in the cur_state bitmask we try a transition
+		for( cur = m->start; cur != NULL; cur = cur->next )
+			if( TEST_BIT( m->cur_state, cur->num ))
+			{
+				tr = cur->tr;
+				if( tr != NULL )
+				{
+					// first we must match the name and attributes
+					if( strcmp( tr->name, "." ) != 0 &&
+						( node->name == NULL || strcasecmp( tr->name, (char *)node->name ) != 0 ))
+						continue;
+					if( tr->attrs != NULL && !attrs_process( tr, node->properties ))
+						continue;
+					// second we can match a machine and regexp
+					if( tr->ptr != NULL && !tree_process( tr->ptr, node->children ))
+						continue;
+					if( tr->re.re_magic != 0 && !regex_process( tr, (char *)node->content ))
+						continue;
+					// we have a winner! add E(st) to the next state bitmap
+					OR( m->next_state, m->E[tr->st->num], m->states );
+				}
+			}
+		// advance input
+		node = node->next;
+
+		// swap cur_state and next_state pointers, saves us a copy operation
+		e = m->cur_state;
+		m->cur_state = m->next_state;
+		m->next_state = e;
+	}
+
+	// the machine accepts the input if we end up in the final state
+	done = TEST_BIT( m->cur_state, m->final->num );
+	return done;
+}
+
+// extracts regex matches from a machine after it has been run
+struct regex_match *find_matches( struct state *s, struct regex_match *m )
+{
+	struct regex_match *cur, *head;
+	struct trans *tr;
+	struct attribute *attr;
+	int i;
+
+	if( s == NULL )
+		return m;
+
+	// recurse to next state first, so we can add the matches in the current state to the
+	// front of the list
+	m = find_matches( s->next, m );
+
+	// grab matches in this state
+	tr = s->tr;
+	if( tr != NULL )
+	{
+		// the -> comes after <foo> in the expression, so search it first
+		if( tr->ptr != NULL )
+			m = find_matches( tr->ptr->start, m );
+
+		// next search : "foo"
+		if( tr->str != NULL )
+		{
+			// loop backwards so that list builds forwards
+			for( i = RESUBR - 1; i > 0; i-- )
+				if( tr->match[i].rm_eo != -1 )
+				{
+					cur = zalloc( sizeof( struct regex_match ));
+					cur->match = tr->match[i];
+					cur->str = tr->str;
+					cur->next = m;
+					m = cur;
+				}
+		}
+
+		// last search <foo>
+		// loop forwards because we have no choice, but build list backwards
+		head = NULL;
+		cur = NULL;
+		for( attr = tr->attrs; attr != NULL; attr = attr->next )
+		{
+			if( attr->str == NULL )
+				continue;
+			for( i = 1; i < RESUBR; i++ )
+				if( attr->match[i].rm_eo != -1 )
+				{
+					if( head == NULL )
+						cur = head = zalloc( sizeof( struct regex_match ));
+					else
+						cur = cur->next = zalloc( sizeof( struct regex_match ));
+					cur->match = attr->match[i];
+					cur->str = attr->str;
+					cur->next = NULL;
+				}
+		}
+		if( head != NULL )
+		{
+			cur->next = m;
+			m = head;
+		}
+	}
+	return m;
+}
+
+// runs machine m on each xml node at this level, then recurses to it's children, building a
+// list of matches
+struct match *node_recurse( struct machine *m, xmlNodePtr node, struct match *n )
+{
+	xmlNodePtr cur, next;
+	struct match *xml;
+
+	if( node == NULL )
+		return n;
+	for( cur = node; cur != NULL; cur = cur->next )
+	{
+		// this will consider each node by itself (without siblings)
+		next = cur->next;
+		cur->next = NULL;
+		if( tree_process( m, cur ))
+		{
+			xml = zalloc( sizeof( struct match ));
+			xml->next = n;
+			xml->node = cur;
+			xml->re = find_matches( m->start, NULL );
+			n = xml;
+		}
+		cur->next = next;
+		// recurse to children
+		n = node_recurse( m, cur->children, n );
+	}
+	return n;
+}
+
+// run a machine on each node in an xml document and return a list of matches
+struct match *document_process( struct machine *m, xmlDocPtr doc )
+{
+	return node_recurse( m, doc->children->next, NULL );
+}
diff --git a/treexpr.h b/treexpr.h
new file mode 100644
index 0000000..c424a54
--- /dev/null
+++ b/treexpr.h
@@ -0,0 +1,107 @@
+/* treexpr.h - Tree expression language header
+ + Copyright (C) 2005 David Barksdale
+ +
+ +  This library is free software; you can redistribute it and/or
+ +  modify it under the terms of the GNU Lesser General Public
+ +  License as published by the Free Software Foundation; either
+ +  version 2.1 of the License, or (at your option) any later version.
+ +
+ +  This library is distributed in the hope that it will be useful,
+ +  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ +  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ +  Lesser General Public License for more details.
+ +
+ +  You should have received a copy of the GNU Lesser General Public
+ +  License along with this library; if not, write to the Free Software
+ +  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef _TREEXPR_H_
+#define _TREEXPR_H_
+
+#include <libxml/tree.h>
+#include <sys/types.h>
+#include "regex.h"
+
+/*
+ * State machines
+ */
+
+struct state;
+
+struct epsilon
+{
+	struct epsilon *next;
+	struct state *st;
+};
+
+#define RESUBR	( 10 )
+
+struct attribute
+{
+	struct attribute *next;
+	char *name; // name of attribute to match
+	regex_t re; // compiled regular expression to match
+	regmatch_t match[RESUBR]; // matches
+	char *str; // string containing matches
+};
+
+struct trans
+{
+	struct state *st;	// state we transition to upon match
+	// stuff to match
+	char *name;			// name of tag to match against
+	regex_t re;			// compiled regular expression to match against contents
+	regmatch_t match[RESUBR]; // matches
+	char *str;			// string containing matches
+	struct attribute *attrs; // attributes to match against
+	struct machine *ptr; // machine to match children
+};
+
+struct state
+{
+	struct trans *tr; // optional transition
+	struct epsilon *ep;	// list of epsilon transitions
+	int num; // state number (generated at run time)
+	// graph traversal
+	struct state *next; // internal list of states for a machine
+};
+
+struct machine
+{
+	struct state *start; // start state
+	struct state *final; // final state (yes, only one)
+	// parse errors
+	const char *error, *buf;
+	// execution
+	int states; // number of states
+	int **E; // arrays of bit masks for E function
+	// I moved these here to make repeated execution a little faster
+	// we alloc these buffers on the first execution and then reuse them
+	int *cur_state; 
+	int *next_state;
+};
+
+/* Matches */
+
+struct regex_match
+{
+	struct regex_match *next;
+	regmatch_t match; // match
+	char *str; // string containing match
+};
+
+struct match
+{
+	struct match *next;
+	xmlNodePtr node; // root node of tree match
+	struct regex_match *re; // list of regular expression matches
+};
+
+/* Public functions */
+
+const char *parse_treexpr( const char *expr, struct machine **m );
+void free_machine( struct machine *m );
+struct match *document_process( struct machine *m, xmlDocPtr doc );
+
+#endif