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POCreating custom CFDictionary callbacks
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copied!<p>I am trying to implement categories for NSMutableDictionary class with at least two methods: one for NSDictionary that <strong>retains</strong> (not copies) its keys, and one for NSDictionary that <strong>weak references</strong> its keys (i.e. does nothing to them).</p> <p>Values are simply retained in both cases.</p> <p>Thus, as CFDictionaryRef is said to be toll-free bridged with NSDictionary, I actually do the following:</p> <pre><code>+ (NSMutableDictionary *)dictionaryWithWeakReferencedKeysForCapacity: (NSUInteger)capacity { CFDictionaryKeyCallBacks keyCallbacks = { 0, NULL, NULL, CFCopyDescription, CFEqual, NULL }; CFDictionaryValueCallBacks valueCallbacks = { 0, ___f_KBWS_DICTIONARY_RETAIN_CALLBACK, ___f_KBWS_DICTIONARY_RELEASE_CALLBACK, CFCopyDescription, CFEqual }; return [(id)CFDictionaryCreateMutable(NULL, capacity, &keyCallbacks, &valueCallbacks) autorelease]; } </code></pre> <p>The second method (for retained keys) looks alike and is not presented here. Scary functions inside the code are:</p> <pre><code>static const void *___f_KBWS_DICTIONARY_RETAIN_CALLBACK(CFAllocatorRef allocator, const void *value) { id object = (id)value; return [object retain]; }; static void ___f_KBWS_DICTIONARY_RELEASE_CALLBACK(CFAllocatorRef allocator, const void *value) { id object = (id)value; return [object release]; }; </code></pre> <p>I had to write these myself as soon as I haven't found standard core foundation callbacks for retaining and releasing keys.</p> <p>I plan to use these categories for dictionaries that will store subclasses NSObjects only. The question is: are these valid callbacks for this case? Is there something wrong in my code besides that?</p>

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