From 526f5470cfa19f27039e287434eb6d26a7671bdd Mon Sep 17 00:00:00 2001
From: Rich Hickey <richhickey@gmail.com>
Date: Mon, 5 Jun 2006 17:25:36 +0000
Subject: distinguished inner/leaf entries

---
 src/cli/runtime/PersistentArray.cs           | 66 +++++++++++++++++++---------
 src/org/clojure/runtime/PersistentArray.java | 33 +++++++++++---
 2 files changed, 72 insertions(+), 27 deletions(-)

(limited to 'src')

diff --git a/src/cli/runtime/PersistentArray.cs b/src/cli/runtime/PersistentArray.cs
index f1b9b0ed..164afc2c 100644
--- a/src/cli/runtime/PersistentArray.cs
+++ b/src/cli/runtime/PersistentArray.cs
@@ -73,30 +73,54 @@ internal class Master{
 		}
 }
 
-	internal class Entry
+internal class Entry
+	{
+	internal readonly int rev;
+	internal readonly Object val;
+
+	internal Entry(int rev, Object val)
 		{
-		internal readonly int rev;
-		internal readonly Object val;
-		internal readonly Entry rest;
+		this.rev = rev;
+		this.val = val;
+		}
 
-		internal Entry(int rev, Object val, Entry rest)
-			{
-			this.rev = rev;
-			this.val = val;
-			this.rest = rest;
-			}
-}
+	internal virtual Entry rest()
+		{
+		return null;
+		}
 
-	internal class ValIter : IEnumerator
+	internal static Entry create(int rev, Object val, Entry rest)
 		{
-		internal PersistentArray p;
-		internal int i;
+		if (rest == null)
+			return new Entry(rev, val);
+		return new EntryLink(rev, val, rest);
+		}
+	}
 
-		internal ValIter(PersistentArray p)
-			{
-		this.p = p;
-		this.i = -1;
+internal class EntryLink : Entry
+	{
+	internal readonly Entry _rest;
+
+	internal EntryLink(int rev, Object val, Entry rest) :base(rev,val)
+		{
+		this._rest = rest;
+		}
+		
+	override internal Entry rest(){
+		return _rest;
 	}
+}
+
+internal class ValIter : IEnumerator
+	{
+	internal PersistentArray p;
+	internal int i;
+
+	internal ValIter(PersistentArray p)
+		{
+	this.p = p;
+	this.i = -1;
+}
 
 #region IEnumerator Members
 
@@ -174,7 +198,7 @@ public PersistentArray resize(int newLength)
 		Entry e = getEntry(i);
 		if (e != null)
 			{
-			ret.master.array[i] = new Entry(0, e.val, null);
+			ret.master.array[i] = Entry.create(0, e.val, null);
 			++ret.master.load;
 			}
 		}
@@ -191,7 +215,7 @@ public PersistentArray isolate()
 	}
 	
 Entry getEntry(int i){
-	for(Entry e = (Entry) master.array[i];e != null;e = e.rest)
+	for(Entry e = (Entry) master.array[i];e != null;e = e.rest())
 		{
 		if(e.rev <= rev)
 			{
@@ -216,7 +240,7 @@ void doSet(int i, Object val){
 	lock(master.array)
 		{
 		oldEntry = (Entry) master.array[i];
-		newEntry = new Entry(rev, val, oldEntry);
+		newEntry = Entry.create(rev, val, oldEntry);
 		master.array[i] = newEntry;
 		}
 	Interlocked.Increment(ref master.load);
diff --git a/src/org/clojure/runtime/PersistentArray.java b/src/org/clojure/runtime/PersistentArray.java
index 30fd2636..9a0acc6d 100644
--- a/src/org/clojure/runtime/PersistentArray.java
+++ b/src/org/clojure/runtime/PersistentArray.java
@@ -74,13 +74,34 @@ static class Master{
 static class Entry{
 	final int rev;
 	final Object val;
-	final Entry rest;
 
-	Entry(int rev,Object val,Entry rest){
+	Entry(int rev,Object val){
 		this.rev = rev;
 		this.val = val;
-		this.rest = rest;
 		}
+
+    Entry rest(){
+        return null;
+    }
+
+    static Entry create(int rev,Object val,Entry rest){
+        if(rest == null)
+            return new Entry(rev,val);
+        return new EntryLink(rev, val, rest);
+    }
+}
+
+static class EntryLink extends Entry{
+	final Entry _rest;
+
+	EntryLink(int rev,Object val,Entry rest){
+        super(rev,val);
+		this._rest = rest;
+		}
+
+    Entry rest(){
+        return _rest;
+    }
 }
 
 static class ValIter implements Iterator{
@@ -157,7 +178,7 @@ public PersistentArray resize(int newLength) {
         Entry e = getEntry(i);
         if(e != null)
             {
-            ret.master.array.set(i,new Entry(0,e.val, null));
+            ret.master.array.set(i,Entry.create(0,e.val, null));
             ++load;
             }
         }
@@ -180,7 +201,7 @@ public PersistentArray isolate() {
 }
 
 Entry getEntry(int i){
-	for(Entry e = (Entry) master.array.get(i);e != null;e = e.rest)
+	for(Entry e = (Entry) master.array.get(i);e != null;e = e.rest())
 		{
 		if(e.rev <= rev)
 			{
@@ -205,7 +226,7 @@ void doSet(int i, Object val){
 	do
 		{
 		oldEntry = (Entry) master.array.get(i);
-		newEntry = new Entry(rev, val, oldEntry);
+		newEntry = Entry.create(rev, val, oldEntry);
 		} while(!master.array.compareAndSet(i, oldEntry, newEntry));
     master.load.incrementAndGet();
 }
-- 
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