NSMapTable mishandles overwriting values

[Alexander Malmberg]

Hi,

NSMapTable doesn't properly handle the case where you call NSMapInsert()
on a key that already has a value. Specifically:

NSMapTable *mt;
id o=[Object class];

mt=NSCreateMapTable(NSNonRetainedObjectMapKeyCallBacks,
       NSIntMapValueCallBacks,1);

NSMapInsert(mt,o,(void *)5);
NSMapInsert(mt,o,(void *)7);
printf("now %i\n",NSMapGet(mt,o));
NSMapRemove(mt,o);
printf("now %i\n",NSMapGet(mt,o)); /* should print '0', prints '5' */

I've attached a patch that fixes this. (It could be optimized to modify
the value in place with additional complexity.)

- Alexander Malmberg

Index: Source/NSMapTable.m
===================================================================
RCS file: /cvsroot/gnustep/gnustep/core/base/Source/NSMapTable.m,v
retrieving revision 1.27
diff -u -r1.27 NSMapTable.m
--- Source/NSMapTable.m 13 Feb 2002 22:25:38 -0000      1.27
+++ Source/NSMapTable.m 7 Mar 2002 21:59:53 -0000
@@ -367,6 +367,7 @@
 NSMapInsert(NSMapTable *table, const void *key, const void *value)
 {
   GSIMapTable  t = (GSIMapTable)table;
+  GSIMapNode    n;
 
   if (table == 0)
     {
@@ -378,6 +379,9 @@
       [NSException raise: NSInvalidArgumentException
                  format: @"Attempt to place notAKeyMarker in map table"];
     }
+  n = GSIMapNodeForKey(t, (GSIMapKey)key);
+  if (n != 0)
+    GSIMapRemoveKey(t, (GSIMapKey)key);
   GSIMapAddPair(t, (GSIMapKey)key, (GSIMapVal)value);  
 }