计算大CRC32的正确方法是什么 [英] What is the correct way of calculating a large CRC32

问题描述

这里是一篇介绍如何使用现代 x86-64 处理器中的内置 CRC32 指令计算最大 1024 字节的 CRC32.但是，我需要计算超过 1024 个字节的 CRC32.计算每个 1024 字节块的 CRC32 并最终将它们相加是一种正确的方法，还是不正确?如果是这样，正确的做法是什么?

Here is an article that describes how to calculate CRC32 of maximum 1024 bytes using the built in CRC32 instruction found in modern x86-64 processors. However, I need to calculate CRC32 of more than 1024 bytes. Would it be a correct approach to calculate CRC32 of each block of 1024 bytes and in the end sum them, or is it incorrect? If so, what is the correct way to do it?

推荐答案

不，只是添加不能解决问题.

No, just adding won't do the job.

您链接的文章告诉我们如何操作:

The article you linked tells us how to do it:

一次计算的 CRC 输出用作计算的初始 CRC下一个计算 [...]

The CRC output of one calculation is used as the initial CRC for the next calculation [...]

要覆盖最终结果大于 0xffffffff 的情况，只需执行 crc32 = ~crc32 &0xffffffff 最终计算后.

To cover the case of the final result being larger then 0xffffffff just do crc32 = ~crc32 & 0xffffffff after the final calculation.

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