0,0 → 1,128 |
/* 7zCrc.c -- CRC32 init |
2015-03-10 : Igor Pavlov : Public domain */ |
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#include "Precomp.h" |
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#include "7zCrc.h" |
#include "CpuArch.h" |
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#define kCrcPoly 0xEDB88320 |
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#ifdef MY_CPU_LE |
#define CRC_NUM_TABLES 8 |
#else |
#define CRC_NUM_TABLES 9 |
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#define CRC_UINT32_SWAP(v) ((v >> 24) | ((v >> 8) & 0xFF00) | ((v << 8) & 0xFF0000) | (v << 24)) |
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UInt32 MY_FAST_CALL CrcUpdateT1_BeT4(UInt32 v, const void *data, size_t size, const UInt32 *table); |
UInt32 MY_FAST_CALL CrcUpdateT1_BeT8(UInt32 v, const void *data, size_t size, const UInt32 *table); |
#endif |
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#ifndef MY_CPU_BE |
UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table); |
UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table); |
#endif |
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typedef UInt32 (MY_FAST_CALL *CRC_FUNC)(UInt32 v, const void *data, size_t size, const UInt32 *table); |
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CRC_FUNC g_CrcUpdateT4; |
CRC_FUNC g_CrcUpdateT8; |
CRC_FUNC g_CrcUpdate; |
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UInt32 g_CrcTable[256 * CRC_NUM_TABLES]; |
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UInt32 MY_FAST_CALL CrcUpdate(UInt32 v, const void *data, size_t size) |
{ |
return g_CrcUpdate(v, data, size, g_CrcTable); |
} |
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UInt32 MY_FAST_CALL CrcCalc(const void *data, size_t size) |
{ |
return g_CrcUpdate(CRC_INIT_VAL, data, size, g_CrcTable) ^ CRC_INIT_VAL; |
} |
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#define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8)) |
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UInt32 MY_FAST_CALL CrcUpdateT1(UInt32 v, const void *data, size_t size, const UInt32 *table) |
{ |
const Byte *p = (const Byte *)data; |
const Byte *pEnd = p + size; |
for (; p != pEnd; p++) |
v = CRC_UPDATE_BYTE_2(v, *p); |
return v; |
} |
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void MY_FAST_CALL CrcGenerateTable() |
{ |
UInt32 i; |
for (i = 0; i < 256; i++) |
{ |
UInt32 r = i; |
unsigned j; |
for (j = 0; j < 8; j++) |
r = (r >> 1) ^ (kCrcPoly & ~((r & 1) - 1)); |
g_CrcTable[i] = r; |
} |
for (; i < 256 * CRC_NUM_TABLES; i++) |
{ |
UInt32 r = g_CrcTable[i - 256]; |
g_CrcTable[i] = g_CrcTable[r & 0xFF] ^ (r >> 8); |
} |
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#if CRC_NUM_TABLES < 4 |
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g_CrcUpdate = CrcUpdateT1; |
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#else |
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#ifdef MY_CPU_LE |
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g_CrcUpdateT4 = CrcUpdateT4; |
g_CrcUpdate = CrcUpdateT4; |
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#if CRC_NUM_TABLES >= 8 |
g_CrcUpdateT8 = CrcUpdateT8; |
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#ifdef MY_CPU_X86_OR_AMD64 |
if (!CPU_Is_InOrder()) |
g_CrcUpdate = CrcUpdateT8; |
#endif |
#endif |
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#else |
{ |
#ifndef MY_CPU_BE |
UInt32 k = 0x01020304; |
const Byte *p = (const Byte *)&k; |
if (p[0] == 4 && p[1] == 3) |
{ |
g_CrcUpdateT4 = CrcUpdateT4; |
g_CrcUpdate = CrcUpdateT4; |
#if CRC_NUM_TABLES >= 8 |
g_CrcUpdateT8 = CrcUpdateT8; |
// g_CrcUpdate = CrcUpdateT8; |
#endif |
} |
else if (p[0] != 1 || p[1] != 2) |
g_CrcUpdate = CrcUpdateT1; |
else |
#endif |
{ |
for (i = 256 * CRC_NUM_TABLES - 1; i >= 256; i--) |
{ |
UInt32 x = g_CrcTable[i - 256]; |
g_CrcTable[i] = CRC_UINT32_SWAP(x); |
} |
g_CrcUpdateT4 = CrcUpdateT1_BeT4; |
g_CrcUpdate = CrcUpdateT1_BeT4; |
#if CRC_NUM_TABLES >= 8 |
g_CrcUpdateT8 = CrcUpdateT1_BeT8; |
// g_CrcUpdate = CrcUpdateT1_BeT8; |
#endif |
} |
} |
#endif |
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#endif |
} |