From c318f7c60e4cff91b0591d1e9dc8bee63c716404 Mon Sep 17 00:00:00 2001
From: Rich Hickey <richhickey@gmail.com>
Date: Sat, 5 Aug 2006 22:39:38 +0000
Subject: added equals and hashcode to maps

---
 src/cli/runtime/APersistentMap.cs | 33 +++++++++++++++++++++++++++++++++
 src/cli/runtime/RT.cs             | 12 ++++++++++++
 2 files changed, 45 insertions(+)

(limited to 'src/cli/runtime')

diff --git a/src/cli/runtime/APersistentMap.cs b/src/cli/runtime/APersistentMap.cs
index 99ca0ea4..8c082d23 100644
--- a/src/cli/runtime/APersistentMap.cs
+++ b/src/cli/runtime/APersistentMap.cs
@@ -15,6 +15,7 @@ using System.Collections;
 namespace clojure.lang
 {
 public abstract class APersistentMap : Obj, IPersistentMap{
+	int _hash = -1;
 
 	public override Obj withMeta(IPersistentMap meta)
 		{
@@ -25,7 +26,39 @@ public abstract class APersistentMap : Obj, IPersistentMap{
 		return ret;
 		}
 
+override public bool Equals(Object obj) {
+    IPersistentMap m = obj as IPersistentMap;
+    if(obj == null)
+        return false;
+        
+    if(m.count() != count())
+        return false;
 
+    for(ISeq s = seq();s!=null;s = s.rest())
+        {
+        IMapEntry e = (IMapEntry) s.first();
+        IMapEntry me = m.find(e.key());
+
+        if(me == null || !RT.equal(e.val(),me.val()))
+            return false;
+        }
+
+    return true;
+}
+
+override public int GetHashCode() {
+    if(_hash == -1)
+        {
+        int hash = count();
+        for(ISeq s = seq();s!=null;s = s.rest())
+            {
+            IMapEntry e = (IMapEntry) s.first();
+            hash ^= RT.hashCombine(RT.hash(e.key()), RT.hash(e.val()));
+            }
+        this._hash = hash;
+        }
+    return _hash;
+}
 	#region IPersistentMap Members
 
 	abstract public IPersistentMap assocEx(object key, object val);
diff --git a/src/cli/runtime/RT.cs b/src/cli/runtime/RT.cs
index 2d7e765e..eab52dfa 100644
--- a/src/cli/runtime/RT.cs
+++ b/src/cli/runtime/RT.cs
@@ -69,6 +69,18 @@ static public bool equal(Object k1,Object k2){
 	//    ?T:null;
 	//    }
 
+static public int hash(Object o){
+    if(o == null)
+        return 0;
+    return o.GetHashCode();
+}
+
+static public int hashCombine(int seed, int hash){
+    //a la boost
+    seed ^= (int)(hash + 0x9e3779b9 + (seed << 6) + (seed >> 2));
+    return seed;
+}
+
 static public ISeq seq(Object coll) {
     if(coll == null || coll is ISeq)
         return (ISeq) coll;
-- 
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