* hash.c (remhash): Rewrote buggy function.

It was decrementing the hash count without checking that
something was deleted from the chain. The deletion was done
incorrectly, without regard for the kind of comparison fucntion
used by the hash table.

2 files changed, 17 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index ebd302d9..63434df7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2012-02-22  Kaz Kylheku  <kaz@kylheku.com>
 
+	* hash.c (remhash): Rewrote buggy function.
+	It was decrementing the hash count without checking that
+	something was deleted from the chain. The deletion was done
+	incorrectly, without regard for the kind of comparison fucntion
+	used by the hash table.
+
+2012-02-22  Kaz Kylheku  <kaz@kylheku.com>
+
 	* eval.c (eval_init): Intrinsic bindings for sub, ref, refset
 	and replace.
 
diff --git a/hash.c b/hash.c
index 32868569..d052c637 100644
--- a/hash.c
+++ b/hash.c
@@ -342,9 +342,15 @@ val remhash(val hash, val key)
 {
   struct hash *h = (struct hash *) cobj_handle(hash, hash_s);
   val *pchain = vecref_l(h->table, num(h->hash_fun(key) % h->modulus));
-  *pchain = alist_remove1(*pchain, key);
-  h->count--;
-  bug_unless (h->count >= 0);
+  val existing = h->assoc_fun(key, *pchain);
+
+  if (existing) {
+    val loc = memq(existing, *pchain);
+    *pchain = nappend2(ldiff(*pchain, loc), cdr(loc));
+    h->count--;
+    bug_unless (h->count >= 0);
+  }
+
   return nil;
 }