Mercurial > hg > nginx-quic
view src/core/ngx_crc.h @ 4434:80df7b82d3c9 stable-1.0
Merge r4336:
Microoptimization of sendfile(2) usage under FreeBSD.
FreeBSD kernel checks headers/trailers pointer against NULL, not
corresponding count. Passing NULL if there are no headers/trailers
helps to avoid unneeded work in kernel, as well as unexpected 0 bytes
GIO in traces.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Sun, 05 Feb 2012 12:42:36 +0000 |
parents | 99858705b03f |
children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #ifndef _NGX_CRC_H_INCLUDED_ #define _NGX_CRC_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> /* 32-bit crc16 */ static ngx_inline uint32_t ngx_crc(u_char *data, size_t len) { uint32_t sum; for (sum = 0; len; len--) { /* * gcc 2.95.2 x86 and icc 7.1.006 compile * that operator into the single "rol" opcode, * msvc 6.0sp2 compiles it into four opcodes. */ sum = sum >> 1 | sum << 31; sum += *data++; } return sum; } #endif /* _NGX_CRC_H_INCLUDED_ */