51 lines
943 B
C
51 lines
943 B
C
// crc32.c
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// WeChat Embedded
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//
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// Created by harlliu on 14-03-03.
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// Copyright 2014 Tencent. All rights reserved.
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//
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#include "prf_defs.h"
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#if (WX_AIRSYNC_CFG)
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#include <stdio.h>
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#include "wechar_crc.h"
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#define DO1(buf) crc = crc_table(((int)crc ^ (*buf++)) & 0xff) ^ (crc >> 8);
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#define DO2(buf) DO1(buf); DO1(buf);
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#define DO4(buf) DO2(buf); DO2(buf);
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#define DO8(buf) DO4(buf); DO4(buf);
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static uint32_t crc_table(uint32_t index)
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{
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uint32_t c = index;
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uint32_t poly = 0xedb88320L;
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int k;
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for (k = 0; k < 8; k++)
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c = c & 1 ? poly ^ (c >> 1) : c >> 1;
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return c;
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}
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uint32_t crc32(uint32_t crc, const uint8_t *buf, int len)
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{
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if (buf == NULL) return 0L;
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crc = crc ^ 0xffffffffL;
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while (len >= 8)
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{
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DO8(buf);
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len -= 8;
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}
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if (len) do {
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DO1(buf);
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} while (--len);
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return crc ^ 0xffffffffL;
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}
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#endif ///WX_AIRSYNC_CFG
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