made seq.count constant-time

1 files changed, 13 insertions, 6 deletions

diff --git a/src/cli/runtime/PersistentTreeMap.cs b/src/cli/runtime/PersistentTreeMap.cs
index cbf366c9..77be3e9f 100644
--- a/src/cli/runtime/PersistentTreeMap.cs
+++ b/src/cli/runtime/PersistentTreeMap.cs
@@ -89,13 +89,13 @@ override public IPersistentMap without(Object key){
 
 override public ISeq seq() {

     if(_count > 0)

-        return Seq.create(tree, true);

+        return Seq.create(tree, true,_count);

     return null;

 }
 
 public ISeq rseq() {

     if(_count > 0)

-        return Seq.create(tree, false);

+        return Seq.create(tree, false,_count);

     return null;

 }
 
@@ -636,14 +636,16 @@ class RedBranchVal : RedBranch{
 public class Seq : ASeq{

 	readonly ISeq stack;

 	readonly bool asc;

+	readonly int cnt;

 

-    Seq(ISeq stack, bool asc) {

+    Seq(ISeq stack, bool asc, int cnt) {

         this.stack = stack;

         this.asc = asc;

+    	this.cnt = cnt;

     }

 

-    internal static Seq create(Node t, bool asc){

-		return new Seq(push(t, null, asc),asc);

+    internal static Seq create(Node t, bool asc,int cnt){

+		return new Seq(push(t, null, asc),asc,cnt);

 	}

 

 	static ISeq push(Node t, ISeq stack, bool asc){

@@ -664,10 +666,15 @@ public class Seq : ASeq{
         ISeq nextstack = push(asc ? t.right() : t.left(), stack.rest(), asc);

         if(nextstack != null)

             {

-            return new Seq(nextstack,asc);

+            return new Seq(nextstack,asc,cnt-1);

             }

         return null;

     }

+

+	public override int count()

+	{

+		return cnt;

+	}

 }