initial commit

.gitignore

@@ -0,0 +1 @@
+a.out

MANotificationCenter.h

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+
+#import <Foundation/Foundation.h>
+
+
+@interface MANotificationCenter : NSObject
+{
+    CFMutableDictionaryRef _objectsDict;
+}
+
+- (id)addObserverForName: (NSString *)name object: (id)object block: (void (^)(NSNotification *note))block;
+- (void)removeObserver: (id)observer;
+
+- (void)postNotification: (NSNotification *)note;
+
+@end

MANotificationCenter.m

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+
+#import "MANotificationCenter.h"
+
+
+@implementation MANotificationCenter
+
+- (id)init
+{
+    if((self = [super init]))
+    {
+        _objectsDict = CFDictionaryCreateMutable(NULL, 0, NULL, &kCFTypeDictionaryValueCallBacks);
+    }
+    return self;
+}
+
+- (void)dealloc
+{
+    CFRelease(_objectsDict);
+    [super dealloc];
+}
+
+- (id)addObserverForName: (NSString *)name object: (id)object block: (void (^)(NSNotification *note))block
+{
+    NSMutableDictionary *innerDict = (id)CFDictionaryGetValue(_objectsDict, object);
+    if(!innerDict)
+    {
+        innerDict = [NSMutableDictionary dictionary];
+        CFDictionarySetValue(_objectsDict, object, innerDict);
+    }
+
+    NSMutableSet *observerBlocks = [innerDict objectForKey: name];
+    if(!observerBlocks)
+    {
+        observerBlocks = [NSMutableSet set];
+        [innerDict setObject: observerBlocks forKey: name];
+    }
+
+    void (^copiedBlock)(NSNotification *note);
+    copiedBlock = [block copy];
+
+    [observerBlocks addObject: copiedBlock];
+
+    [copiedBlock release];
+
+    __block id weakObject = object;
+    void (^removalBlock)(void) = ^{
+        NSMutableDictionary *innerDict = (id)CFDictionaryGetValue(_objectsDict, weakObject);
+        NSMutableSet *observerBlocks = [innerDict objectForKey: name];
+        [observerBlocks removeObject: copiedBlock];
+        if([observerBlocks count] == 0)
+            [innerDict removeObjectForKey: name];
+        if([innerDict count] == 0)
+            CFDictionaryRemoveValue(_objectsDict, weakObject);
+    };
+
+    return [[removalBlock copy] autorelease];
+}
+
+- (void)removeObserver: (id)observer
+{
+    void (^removalBlock)(void) = observer;
+    removalBlock();
+}
+
+- (void)postNotification: (NSNotification *)note
+{
+    NSDictionary *innerDict = (id)CFDictionaryGetValue(_objectsDict, [note object]);
+    NSSet *observerBlocks = [innerDict objectForKey: [note name]];
+    for(void (^block)(NSNotification *) in observerBlocks)
+        block(note);
+}
+
+@end
+

main.m

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+// gcc -framework Foundation main.m MANotificationCenter.m
+
+#import "MANotificationCenter.h"
+
+
+int main(int argc, char **argv)
+{
+    [NSAutoreleasePool new];
+
+    MANotificationCenter *center = [[MANotificationCenter alloc] init];
+
+    id obj = [[NSObject alloc] init];
+    id otherObj = [[NSObject alloc] init];
+    [center addObserverForName: @"name" object: obj block: ^(NSNotification *note) {
+        NSLog(@"First block got notification %@", note);
+    }];
+    [center addObserverForName: @"name" object: obj block: ^(NSNotification *note) {
+        NSLog(@"Second block got notification %@", note);
+    }];
+    [center addObserverForName: @"othername" object: obj block: ^(NSNotification *note) {
+        NSLog(@"Third block got notification %@", note);
+    }];
+    [center addObserverForName: @"name" object: otherObj block: ^(NSNotification *note) {
+        NSLog(@"Fourth block got notification %@", note);
+    }];
+
+    [center postNotification: [NSNotification notificationWithName: @"name" object: obj]];
+}
+