iOS集合深拷贝

众所周知：浅复制就是指针拷贝(拷贝指向对象的指针)；深复制就是内容拷贝(直接拷贝整个对象内存到另一块内存中)。

不管深复制还是浅复制，都是一级的拷贝；而实际项目应用中，数据往往比较复杂，需要拷贝集合里的所有层级内容。这就需要使用递归思路实现深拷贝。废话不多说，直接上代码。

NSDictionary 深拷贝

-(NSDictionary*)dl_deepCopy{
    NSMutableDictionary *dic = [[NSMutableDictionary alloc] initWithCapacity:[self count]];
    [self enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
        id item = obj;
        if ([item respondsToSelector:@selector(dl_deepCopy)]) {
            item = [item dl_deepCopy];
        } else {
            item = [item copy];
        }
        if (item && key) {
            [dic setObject:item forKey:key];
        }
    }];
    return [NSDictionary dictionaryWithDictionary:dic];
}

-(NSMutableDictionary*)dl_mutableDeepCopy{
    NSMutableDictionary *dic = [[NSMutableDictionary alloc] initWithCapacity:[self count]];
    [self enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
        id item = obj;
        if ([item respondsToSelector:@selector(dl_mutableDeepCopy)]){
            item = [item dl_mutableDeepCopy];
        } else if ([item respondsToSelector:@selector(mutableCopyWithZone:)]) {
            item = [item mutableCopy];
        } else {
            item = [item copy];
        }
        if (item && key) {
            [dic setObject:item forKey:key];
        }
    }];
    return dic;
}

NSArray 深拷贝

-(NSArray*)dl_deepCopy{
    NSMutableArray *array = [[NSMutableArray alloc] initWithCapacity:[self count]];
    [self enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        id item = obj;
        if ([item respondsToSelector:@selector(dl_deepCopy)]) {
            item = [item dl_deepCopy];
        } else {
            item = [item copy];
        }
        if (item) {
            [array addObject:item];
        }
    }];
    return [NSArray arrayWithArray:array];
}

-(NSMutableArray*)dl_mutableDeepCopy{
    NSMutableArray *array = [[NSMutableArray alloc] initWithCapacity:[self count]];
    [self enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        id item = obj;
        if ([item respondsToSelector:@selector(dl_mutableDeepCopy)]){
            item = [item dl_mutableDeepCopy];
        } else if ([item respondsToSelector:@selector(mutableCopyWithZone:)]) {
            item = [item mutableCopy];
        } else {
            item = [item copy];
        }
        if (item) {
            [array addObject:item];
        }
    }];
    return array;
}