1 files changed, 79 insertions, 7 deletions

diff --git a/src/library.js b/src/library.js
index 4508d315..ca3175d1 100644
--- a/src/library.js
+++ b/src/library.js
@@ -1705,7 +1705,7 @@ LibraryManager.library = {
         if (nextC > 0) {
           var maxx = 1;
           if (nextC > formatIndex+1) {
-            var sub = format.substring(formatIndex+1, nextC)
+            var sub = format.substring(formatIndex+1, nextC);
             maxx = parseInt(sub);
             if (maxx != sub) maxx = 0;
           }
@@ -1723,6 +1723,53 @@ LibraryManager.library = {
         }
       }
 
+      // handle %[...]
+      if (format[formatIndex] === '%' && format.indexOf('[', formatIndex+1) > 0) {
+        var match = /\%([0-9]*)\[(\^)?(\]?[^\]]*)\]/.exec(format.substring(formatIndex));
+        if (match) {
+          var maxNumCharacters = parseInt(match[1]) || Infinity;
+          var negateScanList = (match[2] === '^');
+          var scanList = match[3];
+
+          // expand "middle" dashs into character sets
+          var middleDashMatch;
+          while ((middleDashMatch = /([^\-])\-([^\-])/.exec(scanList))) {
+            var rangeStartCharCode = middleDashMatch[1].charCodeAt(0);
+            var rangeEndCharCode = middleDashMatch[2].charCodeAt(0);
+            for (var expanded = ''; rangeStartCharCode <= rangeEndCharCode; expanded += String.fromCharCode(rangeStartCharCode++));
+            scanList = scanList.replace(middleDashMatch[1] + '-' + middleDashMatch[2], expanded);
+          }
+
+          var argPtr = {{{ makeGetValue('varargs', 'argIndex', 'void*') }}};
+          argIndex += Runtime.getAlignSize('void*', null, true);
+          fields++;
+
+          for (var i = 0; i < maxNumCharacters; i++) {
+            next = get();
+            if (negateScanList) {
+              if (scanList.indexOf(String.fromCharCode(next)) < 0) {
+                {{{ makeSetValue('argPtr++', 0, 'next', 'i8') }}};
+              } else {
+                unget();
+                break;
+              }
+            } else {
+              if (scanList.indexOf(String.fromCharCode(next)) >= 0) {
+                {{{ makeSetValue('argPtr++', 0, 'next', 'i8') }}};
+              } else {
+                unget();
+                break;
+              }
+            }
+          }
+
+          // write out null-terminating character
+          {{{ makeSetValue('argPtr++', 0, '0', 'i8') }}};
+          formatIndex += match[0].length;
+          
+          continue;
+        }
+      }      
       // remove whitespace
       while (1) {
         next = get();
@@ -1784,6 +1831,17 @@ LibraryManager.library = {
         } else {
           next = get();
           var first = true;
+          
+          // Strip the optional 0x prefix for %x.
+          if ((type == 'x' || type == 'X') && (next == {{{ charCode('0') }}})) {
+            var peek = get();
+            if (peek == {{{ charCode('x') }}} || peek == {{{ charCode('X') }}}) {
+              next = get();
+            } else {
+              unget();
+            }
+          }
+          
           while ((curr < max_ || isNaN(max_)) && next > 0) {
             if (!(next in __scanString.whiteSpace) && // stop on whitespace
                 (type == 's' ||
@@ -1916,6 +1974,7 @@ LibraryManager.library = {
         var flagLeftAlign = false;
         var flagAlternative = false;
         var flagZeroPad = false;
+        var flagPadSign = false;
         flagsLoop: while (1) {
           switch (next) {
             case {{{ charCode('+') }}}:
@@ -1934,6 +1993,9 @@ LibraryManager.library = {
                 flagZeroPad = true;
                 break;
               }
+            case {{{ charCode(' ') }}}:
+              flagPadSign = true;
+              break;
             default:
               break flagsLoop;
           }
@@ -2100,14 +2162,20 @@ LibraryManager.library = {
             }
 
             // Add sign if needed
-            if (flagAlwaysSigned) {
-              if (currArg < 0) {
-                prefix = '-' + prefix;
-              } else {
+            if (currArg >= 0) {
+              if (flagAlwaysSigned) {
                 prefix = '+' + prefix;
+              } else if (flagPadSign) {
+                prefix = ' ' + prefix;
               }
             }
 
+            // Move sign to prefix so we zero-pad after the sign
+            if (argText.charAt(0) == '-') {
+              prefix = '-' + prefix;
+              argText = argText.substr(1);
+            }
+
             // Add padding.
             while (prefix.length + argText.length < width) {
               if (flagLeftAlign) {
@@ -2190,8 +2258,12 @@ LibraryManager.library = {
               if (next == {{{ charCode('E') }}}) argText = argText.toUpperCase();
 
               // Add sign.
-              if (flagAlwaysSigned && currArg >= 0) {
-                argText = '+' + argText;
+              if (currArg >= 0) {
+                if (flagAlwaysSigned) {
+                  argText = '+' + argText;
+                } else if (flagPadSign) {
+                  argText = ' ' + argText;
+                }
               }
             }