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82 lines
1.8 KiB
C
82 lines
1.8 KiB
C
/*
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* Copyright (C) 2015 Anton Blanchard <anton@au.ibm.com>, IBM
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of either:
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*
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* a) the GNU General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version, or
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* b) the Apache License, Version 2.0
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*/
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#define CRC_TABLE
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#ifdef CRC32_CONSTANTS_HEADER
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#include CRC32_CONSTANTS_HEADER
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#else
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#include "crc32_constants.h"
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#endif
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#define VMX_ALIGN 16
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#define VMX_ALIGN_MASK (VMX_ALIGN - 1)
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#ifdef REFLECT
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static unsigned int crc32_align(unsigned int crc, unsigned char* p, unsigned long len) {
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while (len--)
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crc = crc_table[(crc ^ *p++) & 0xff] ^ (crc >> 8);
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return crc;
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}
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#else
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static unsigned int crc32_align(unsigned int crc, unsigned char* p, unsigned long len) {
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while (len--)
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crc = crc_table[((crc >> 24) ^ *p++) & 0xff] ^ (crc << 8);
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return crc;
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}
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#endif
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#ifndef CRC32_FUNCTION
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#define CRC32_FUNCTION crc32_vpmsum
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#endif
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#ifndef CRC32_FUNCTION_ASM
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#define CRC32_FUNCTION_ASM __crc32_vpmsum
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#endif
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unsigned int CRC32_FUNCTION_ASM(unsigned int crc, unsigned char* p, unsigned long len);
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unsigned int CRC32_FUNCTION(unsigned int crc, unsigned char* p, unsigned long len) {
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unsigned int prealign;
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unsigned int tail;
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#ifdef CRC_XOR
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crc ^= 0xffffffff;
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#endif
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if (len < VMX_ALIGN + VMX_ALIGN_MASK) {
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crc = crc32_align(crc, p, len);
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goto out;
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}
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if ((unsigned long)p & VMX_ALIGN_MASK) {
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prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK);
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crc = crc32_align(crc, p, prealign);
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len -= prealign;
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p += prealign;
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}
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crc = CRC32_FUNCTION_ASM(crc, p, len & ~VMX_ALIGN_MASK);
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tail = len & VMX_ALIGN_MASK;
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if (tail) {
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p += len & ~VMX_ALIGN_MASK;
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crc = crc32_align(crc, p, tail);
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}
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out:
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#ifdef CRC_XOR
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crc ^= 0xffffffff;
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#endif
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return crc;
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}
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