how to decompress gzip stream with zlib

最新推荐文章于 2020-08-11 14:27:04 发布

转载最新推荐文章于 2020-08-11 14:27:04 发布 · 76 阅读

本文介绍如何使用zlib库正确解压缩GZIP格式的文件。关键在于调用inflateInit2时设置windowBits参数为16+MAX_WBITS，以确保zlib能识别GZIP头。

how to decompress gzip stream with zlib

how to decompress gzip stream with zlib

I'm posting this in my journal because it trips me up every time I have to do this, and I need something googleable so I can easily find this info next time.

To decompress a gzip format file with zlib, call inflateInit2 with the windowBits parameter as 16+MAX_WBITS, like this:

inflateInit2(&stream, 16+MAX_WBITS);

If you don't do this, zlib will complain about a bad stream format. By default, zlib creates streams with a zlib header, and on inflate does not recognise the different gzip header unless you tell it so. Although this is documented starting in version 1.2.1 of the zlib.h header file, it is not in the zlib manual.

Update: I've added this as a question (and answer!) on Stack Overflow: How can I decompress a gzip stream with zlib?