TList的快速副本< T> [英] Fast copy of TList <T>?

问题描述

有复制通用TList的快速方法吗？

Is there a fast way to copy a generic TList?

Copy.Capacity := List.Count;
for Item in List do
  Copy.Add (Item);

很慢。似乎没有办法使用 CopyMemory ，因为我不能得到内部数组的内存地址（这从信息隐藏的观点是显而易见的）。我错过了像

is very slow. There seems to be no way to use CopyMemory since I can't get the memory adress of the internal array (which is obvious from an information hiding viewpoint). I miss something like

List.Copy (Copy);

它使用内部表示的知识来提高性能。

对于通用的 TList< T> ，可以做到吗？

which uses the knowledge of the internal representation to improve performance. Can it be done?

推荐答案

它根本不可能实现你想要的功能。这是因为复制 T 的内容可能涉及多个简单的内存复制。如果 T 包含任何托管类型（即字符串，接口等），那么这些托管对象的引用计数必须递增。

For the generic TList<T> it is simply not possible to implement the function you want. That's because copy the contents of T may involve more than a simple memory copy. If T contains any managed types (i.e. strings, interfaces etc.) then the reference counts on those managed objects must be incremented.

• 如果您的 T 确实包含托管类型，那么我怀疑您可以做得比已经拥有的代码好多少。


• 如果您的 T 不包含任何托管类型，那么内存副本是可行的，但您需要创建自己的类来封装此列表，因为 TList< T> 不合适。

• If your T does contain managed types then I doubt that you can do much better then the code you already have.
• If your T does not contain any managed types then a memory copy is viable but you will need to create your own class to encapsulate this list since TList<T> is not appropriate.

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