diff options
Diffstat (limited to 'src/lib/lib7z/7zCrc.c')
-rw-r--r-- | src/lib/lib7z/7zCrc.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/src/lib/lib7z/7zCrc.c b/src/lib/lib7z/7zCrc.c new file mode 100644 index 00000000000..cd94201be97 --- /dev/null +++ b/src/lib/lib7z/7zCrc.c @@ -0,0 +1,83 @@ +/* 7zCrc.c -- CRC32 init +2010-12-01 : Igor Pavlov : Public domain */ + +#include "7zCrc.h" +#include "CpuArch.h" + +#define kCrcPoly 0xEDB88320 + +#ifdef MY_CPU_X86_OR_AMD64 + #define CRC_NUM_TABLES 8 + UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table); +#elif defined(MY_CPU_LE) + #define CRC_NUM_TABLES 4 +#else + #define CRC_NUM_TABLES 5 + #define CRC_UINT32_SWAP(v) ((v >> 24) | ((v >> 8) & 0xFF00) | ((v << 8) & 0xFF0000) | (v << 24)) + UInt32 MY_FAST_CALL CrcUpdateT1_BeT4(UInt32 v, const void *data, size_t size, const UInt32 *table); +#endif + +#ifndef MY_CPU_BE + UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table); +#endif + +typedef UInt32 (MY_FAST_CALL *CRC_FUNC)(UInt32 v, const void *data, size_t size, const UInt32 *table); + +static CRC_FUNC g_CrcUpdate; +UInt32 g_CrcTable[256 * CRC_NUM_TABLES]; + +UInt32 MY_FAST_CALL CrcUpdate(UInt32 v, const void *data, size_t size) +{ + return g_CrcUpdate(v, data, size, g_CrcTable); +} + +UInt32 MY_FAST_CALL CrcCalc(const void *data, size_t size) +{ + return g_CrcUpdate(CRC_INIT_VAL, data, size, g_CrcTable) ^ CRC_INIT_VAL; +} + +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); + } + + #ifdef MY_CPU_LE + + g_CrcUpdate = CrcUpdateT4; + + #if CRC_NUM_TABLES == 8 + if (!CPU_Is_InOrder()) + g_CrcUpdate = CrcUpdateT8; + #endif + + #else + { + #ifndef MY_CPU_BE + UInt32 k = 1; + if (*(const Byte *)&k == 1) + g_CrcUpdate = CrcUpdateT4; + 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_CrcUpdate = CrcUpdateT1_BeT4; + } + } + #endif +} |