计算循环缓冲区中剩余空间的简化算法？ [英] Simplified algorithm for calculating remaining space in a circular buffer?

问题描述

我想知道是否有一种更简单的（单一）方法来计算循环缓冲区中的剩余空间。

I was wonder if there is a simpler (single) way to calculate the remaining space in a circular buffer than this?

int remaining = (end > start)
                ? end-start
                : bufferSize - start + end;

推荐答案

如果你担心预测不佳的条件你可以使用这个：

If you're worried about poorly-predicted conditionals slowing down your CPU's pipeline, you could use this:

int remaining = (end - start) + (-((int) (end <= start)) & bufferSize);

但这可能是过早的优化（除非你真的将此标识为热点）。坚持你当前的技术，这是更容易阅读。

But that's likely to be premature optimisation (unless you have really identified this as a hotspot). Stick with your current technique, which is much more readable.

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