C ++：向量和列表之间的混合：像std :: rope？ [英] C++: mixture between vector and list: something like std::rope?

问题描述

当存储一堆项目，我不需要随机访问容器，我使用 std :: list 这是很好。然而，有时（特别是当我把条目推回到后面，从来没有删除中间某处），我希望我有一些更好的性能结构来添加条目。

When storing a bunch of items and I don't need random access to the container, I am using an std::list which is mostly fine. However, sometimes (esp. when I just push back entries to the back and never delete somewhere in the middle), I wish I had some structure with better performance for adding entries.

std :: vector 是错误的，因为：

• 必须重新分配


• 它不适用于大量的数据（因为你不能总是获得非常大的连续可用内存）。

std :: list 是错误的，因为：

• 它对每个push_back进行分配。

• It makes an allocation on every single push_back. That is slow and leads to a lot of memory fragmentation.

因此，中间的东西就是我想要的东西。

So, something in between is what I want.

基本上，我想要像 std :: list< boost :: array< T，100> > 左右。或者可以代替 100 ，让它 4096 / sizeof（T）。也许 std :: list< std :: vector< T> > ，并且第一向量可以小，然后进一步向量可以增长。实际上我想要隐藏的使用，所以我可以做一个 mycontainer.push_back（x）。

Basically, I want something like std::list< boost::array<T, 100> > or so. Or maybe instead of 100, let it be 4096/sizeof(T). Maybe also std::list< std::vector<T> > and the first vectors can be small and then further ones can grow. Actually I want to have that hidden from the usage, so I can just do a mycontainer.push_back(x).

std :: rope 有点类似，但它在标准中不可用。

std::rope is a bit similar to that but it is not available in the standard.

有这样的东西

推荐答案

您是否考虑过使用 std :: deque ？它的元素不是连续存储的，但它允许随机访问元素;如果你只是在序列的开头或结尾插入元素，它可能会比 std :: vector 更好的性能。

Have you considered using std::deque? Its elements are not stored contiguously but it does allow random access to elements; if you are only inserting elements at the beginning or end of the sequence, it may give better performance than a std::vector.

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