Mercurial > hg > nginx-quic
view src/core/ngx_crc.h @ 3275:b344b68da8c5
optimize some cycles:
*) delete surplus variable;
*) on i386/amd64 "while (n) / n--" is smaller than "while (n--)",
because the platforms have no postfix operations
author | Igor Sysoev <igor@sysoev.ru> |
---|---|
date | Mon, 02 Nov 2009 17:12:09 +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_ */