* tables of power of two in size are used, collisions are handled by
* chaining. See the source code for more information... :)
*
- * Copyright (c) 2006-2009, Salvatore Sanfilippo <antirez at gmail dot com>
+ * Copyright (c) 2006-2010, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
return DICT_OK;
}
-/* Add an element, discarding the old if the key already exists */
+/* Add an element, discarding the old if the key already exists.
+ * Return 1 if the key was added from scratch, 0 if there was already an
+ * element with such key and dictReplace() just performed a value update
+ * operation. */
int dictReplace(dict *ht, void *key, void *val)
{
- dictEntry *entry;
+ dictEntry *entry, auxentry;
/* Try to add the element. If the key
* does not exists dictAdd will suceed. */
if (dictAdd(ht, key, val) == DICT_OK)
- return DICT_OK;
+ return 1;
/* It already exists, get the entry */
entry = dictFind(ht, key);
/* Free the old value and set the new one */
- dictFreeEntryVal(ht, entry);
+ /* Set the new value and free the old one. Note that it is important
+ * to do that in this order, as the value may just be exactly the same
+ * as the previous one. In this context, think to reference counting,
+ * you want to increment (set), and then decrement (free), and not the
+ * reverse. */
+ auxentry = *entry;
dictSetHashVal(ht, entry, val);
- return DICT_OK;
+ dictFreeEntryVal(ht, &auxentry);
+ return 0;
}
/* Search and remove an element */