Change API for the Compare function

git-svn-id: svn://svn.cc65.org/cc65/trunk@2573 b7a2c559-68d2-44c3-8de9-860c34a00d81

src/common/hashtab.c

@@ -96,7 +96,7 @@ HashNode* HT_Find (const HashTable* T, const void* Key)
          * if it is not really necessary.
          */
         if (N->Hash == Hash &&
-            T->Func->Compare (Key, T->Func->GetKey (N->Entry))) {
+            T->Func->Compare (Key, T->Func->GetKey (N->Entry)) == 0) {
             /* Found */
             break;
         }

src/common/hashtab.h

@@ -75,7 +75,10 @@ struct HashFunctions {
     /* Given a pointer to the user entry data, return a pointer to the hash node */
 
     int (*Compare) (const void* Key1, const void* Key2);
-    /* Compare two keys for equality */
+    /* Compare two keys. The function must return a value less than zero if
+     * Key1 is smaller than Key2, zero if both are equal, and a value greater
+     * than zero if Key1 is greater then Key2.
+     */
 };
 
 /* Hash table */