任何替代std :: dynarray目前可用？ [英] Any alternative to std::dynarray presently available?

问题描述

C ++ 11给了我们很大的 std :: array ，这需要在编译时知道大小：

C++11 gave us great std::array, which requires size to be known at compile time:

std::array<int, 3> myarray = {1, 2, 3};

现在，我碰巧有一些旧 short *

Now, I happen to have some old short* buffers to wrap, whose size will be known (and it will be, of course) at runtime only.

C ++ 14将会定义 std :: dynarray 来覆盖这种情况，但是 dynarray 在GCC 4.7或者Clang 3.2中还不可用。

C++14 will define std::dynarray to cover this case, but dynarray is not available yet in GCC 4.7 nor in Clang 3.2.

所以，有没有人知道一个容器可以比较 std :: array （在效率方面），但不需要指定大小在编译时？

So, does anyone know a container which is comparable to std::array (in terms of efficiency) but does not require to specify size at compile time? I suspect Boost has something ready for me, although I couldn't find anything.

推荐答案

你可以（ab）使用一个 std :: valarray< short> 。

You could (ab)use a std::valarray<short>.

int main() {
    short* raw_array = (short*) malloc(12 * sizeof(short));
    size_t length = 12;
    for (size_t i = 0; i < length; ++ i) {
        raw_array[i] = (short) i;
    }

    // ...

    std::valarray<short> dyn_array (raw_array, length);
    for (short elem : dyn_array) {
        std::cout << elem << std::endl;
    }

    // ...

    free(raw_array);
}

dynarray 的功能：

• 分配器


• 反向迭代器


• .at（）
> .data（）

• allocator
• reverse iterator
• .at()
• .data()

请注意，标准（从n3690开始）不需要 valarray 存储是连续的，虽然没有理由不这样做）。

Note that the standard (as of n3690) does not require valarray storage be continuous, although there's no reason not to do so :).

（对于一些实现细节，在libstdc ++实现为（长度，数据）对，在libc ++中实现为（begin，end）。）

(For some implementation detail, in libstdc++ it is implemented as a (length, data) pair, and in libc++ it is implemented as (begin, end).)

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