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command+control+r

IOS Xcode中快捷键大全

在Xcode 中有许多快捷键的设定可以使得你的编程工作更为高效，对于在代码文件中快速导航、定位Bug以及新增应用特性都是极有效的。 当然，你戳进这篇文章的目的也在于想要快速的...

丿尛峯

2153 2 2

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Using Custom Keys

In most cases, Cocoa-provided objects such as NSString objects should be sufficient for use as keys. In some cases, however, it may be necessary to use custom objects as keys in a dictionary. When using custom objects as keys, there are some important points to keep in mind.

Keys must conform to the NSCopying protocol. Methods that add entries to dictionaries—whether as part of initialization (for all dictionaries) or during modification (for mutable dictionaries)— don’t add each key object to the dictionary directly. Instead, they copy each key argument and add the copy to the dictionary. After being copied into the dictionary, the dictionary-owned copies of the keys should not be modified.

Keys must implement the hash and isEqual: methods because a dictionary uses a hash table to organize its storage and to quickly access contained objects. In addition, performance in a dictionary is heavily dependent on the hash function used. With a bad hash function, the decrease in performance can be severe. For more information on the hash and isEqual: methods see NSObject.

Important: Because the dictionary copies each key, keys must conform to the NSCopying protocol. Bear this in mind when choosing what objects to use as keys. Although you can use any object that adopts the NSCopying protocol and implements the hash and isEqual: methods, it is typically bad design to use large objects, such as instances of NSImage, because doing so may incur performance penalties.
感觉这里解释得更清楚啊。

roylly 评论自iOS使用自定义对象作为NSDictionary的key探索

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CAEAGLLayer是iOS5之后提供的完成OpenGL绘图缓冲的底层配置的

清水_yuxin 评论自CALayer-绪论（iOS论文系列）

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@会飞的樱桃_300e 没毛病 遍历只是开放定址法

iOS管理对象内存的数据结构以及操作算法--SideTables、RefcountMap、weak_table_t-一

第一次写文章语言表达能力太差。如果有哪里表达的不够清晰可以直接评论回复我,我来加以修改。这篇文章力求脱离语言的特性，咱们多讲结构和算法。即使你不懂iOS开发，不懂Object...

iOS入门级攻城尸

22773 43 261 2

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return (i+1) & mask;

iOS实例方法cache_t的缓存逻辑

先放一份流程图： 一、试验： 我们先做个试验： 执行三个方法 代码： 然后打印出类里面的cache 其中_mask是缓存池的最大容量_occupied是缓存池缓存的方法数量 ...

海浪萌物

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