2004-09-28 16:34:51 +08:00
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/*
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2004-09-30 00:00:49 +08:00
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* Copyright (C) Igor Sysoev
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2012-01-18 23:07:43 +08:00
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* Copyright (C) Nginx, Inc.
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2004-09-28 16:34:51 +08:00
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*/
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2003-12-01 04:03:18 +08:00
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#ifndef _NGX_CRC_H_INCLUDED_
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#define _NGX_CRC_H_INCLUDED_
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2006-10-19 16:16:29 +08:00
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#include <ngx_config.h>
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#include <ngx_core.h>
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2003-12-01 04:03:18 +08:00
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/* 32-bit crc16 */
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2006-10-13 23:09:25 +08:00
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static ngx_inline uint32_t
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2006-10-19 02:43:11 +08:00
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ngx_crc(u_char *data, size_t len)
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2003-12-01 04:03:18 +08:00
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{
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uint32_t sum;
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2003-12-09 04:48:12 +08:00
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2003-12-01 04:03:18 +08:00
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for (sum = 0; len; len--) {
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2004-09-28 16:34:51 +08:00
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2003-12-01 04:03:18 +08:00
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/*
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2006-10-13 23:09:25 +08:00
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* gcc 2.95.2 x86 and icc 7.1.006 compile
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* that operator into the single "rol" opcode,
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2003-12-01 04:03:18 +08:00
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* msvc 6.0sp2 compiles it into four opcodes.
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*/
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sum = sum >> 1 | sum << 31;
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sum += *data++;
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}
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return sum;
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}
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#endif /* _NGX_CRC_H_INCLUDED_ */
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