小编Rik*_*rst的帖子

好的,所以我正在做一些涉及键盘输入的东西.我现在有一个像这样的巨大功能:

return key == BB_KEY_SPACE ||
        key == BB_KEY_ZERO ||
        key == BB_KEY_ONE ||
        key == BB_KEY_TWO ||
        key == BB_KEY_THREE ||
        key == BB_KEY_FOUR ||
        key == BB_KEY_FIVE ||
        key == BB_KEY_SIX ||
        key == BB_KEY_SEVEN ||
        key == BB_KEY_EIGHT ||
        key == BB_KEY_NINE ||
        key == BB_KEY_A ||
        key == BB_KEY_B ||
        key == BB_KEY_C ||
        key == BB_KEY_D ||
        key == BB_KEY_E ||
        key == BB_KEY_F ||
        key == BB_KEY_G ||
        key == BB_KEY_H ||
        key == …

所以我一直在忙着编写自己的自定义内存分配器,但是我遇到了一些我不理解的奇怪行为.

考虑以下代码:

void* PointerUtil::AlignForward(void* address, const uint8_t& alignment)
{
    return (void*)(((uintptr_t)(address) + (uintptr_t)(alignment - 1)) & (uintptr_t)(~(alignment - 1)));
}

这应该采用指针和对齐要求,并修改指针使其在正向(正向)上正确对齐.

但是,当我这样测试时:

int address = 1240;

std::cout << (uintptr_t)memory::PointerUtil::AlignForward((void*)((uintptr_t)address), 512) << std::endl;
std::cout << (uintptr_t)memory::PointerUtil::AlignForward((void*)((uintptr_t)address), 256) << std::endl;
std::cout << (uintptr_t)memory::PointerUtil::AlignForward((void*)((uintptr_t)address), 128) << std::endl;
std::cout << (uintptr_t)memory::PointerUtil::AlignForward((void*)((uintptr_t)address), 64) << std::endl;
std::cout << (uintptr_t)memory::PointerUtil::AlignForward((void*)((uintptr_t)address), 32) << std::endl;

我得到的输出是这样的:

0
0
1280
1280
1248

这似乎不对.它应该是:

1536
1280
1280
1280
1248

这里出了什么问题？