如何有效地包装固定大小的循环缓冲区的索引 [英] How to efficiently wrap the index of a fixed-size circular buffer

问题描述

我有一个固定大小的循环缓冲区(实现为数组):初始化后，缓冲区将填充有指定的最大元素数量，这允许使用单个位置索引来跟踪我们当前的位置圆圈.

I have a fixed size circular buffer (implemented as an array): upon initialization, the buffer gets filled with the specified maximum number of elements which allows the use of a single position index in order to keep track of our current position in the circle.

访问循环缓冲区中的元素的有效方法是什么?这是我当前的解决方案:

What is an efficient way to access an element in the circular buffer? Here is my current solution:

int GetElement(int index)
{
    if (index >= buffer_size || index < 0)
    {
        // some code to handle the case
    }
    else
    {
        // wrap the index
        index = end_index + index >= buffer_size ? (index + end_index) - buffer_size : end_index + index;
    }

    return buffer[index];
}

一些定义:
end_index是紧接在圆中最后一个元素之后的元素的索引(也将被视为与start_index或圆的第一个元素相同).
buffer_size是缓冲区的最大大小.

Some definitions:
end_index is the index of the element immediately after the last element in the circle (it would also be considered the same as the start_index, or the first element of the circle).
buffer_size is the maximum size of the buffer.

推荐答案

确保缓冲区始终是两个long的幂并屏蔽掉最高位.

Ensure that the buffer is always a power of two long and mask out the top bits.

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