diff options
Diffstat (limited to 'src/lib/lib7z/7zCrcOpt.c')
-rw-r--r-- | src/lib/lib7z/7zCrcOpt.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/src/lib/lib7z/7zCrcOpt.c b/src/lib/lib7z/7zCrcOpt.c new file mode 100644 index 00000000000..a8d42a80074 --- /dev/null +++ b/src/lib/lib7z/7zCrcOpt.c @@ -0,0 +1,64 @@ +/* 7zCrcOpt.c -- CRC32 calculation +2010-12-01 : Igor Pavlov : Public domain */ + +#include "CpuArch.h" + +#define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8)) + +#ifndef MY_CPU_BE + +UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table) +{ + const Byte *p = (const Byte *)data; + for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++) + v = CRC_UPDATE_BYTE_2(v, *p); + for (; size >= 4; size -= 4, p += 4) + { + v ^= *(const UInt32 *)p; + v = + table[0x300 + (v & 0xFF)] ^ + table[0x200 + ((v >> 8) & 0xFF)] ^ + table[0x100 + ((v >> 16) & 0xFF)] ^ + table[0x000 + ((v >> 24))]; + } + for (; size > 0; size--, p++) + v = CRC_UPDATE_BYTE_2(v, *p); + return v; +} + +UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table) +{ + return CrcUpdateT4(v, data, size, table); +} + +#endif + + +#ifndef MY_CPU_LE + +#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) +{ + const Byte *p = (const Byte *)data; + for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++) + v = CRC_UPDATE_BYTE_2(v, *p); + v = CRC_UINT32_SWAP(v); + table += 0x100; + for (; size >= 4; size -= 4, p += 4) + { + v ^= *(const UInt32 *)p; + v = + table[0x000 + (v & 0xFF)] ^ + table[0x100 + ((v >> 8) & 0xFF)] ^ + table[0x200 + ((v >> 16) & 0xFF)] ^ + table[0x300 + ((v >> 24))]; + } + table -= 0x100; + v = CRC_UINT32_SWAP(v); + for (; size > 0; size--, p++) + v = CRC_UPDATE_BYTE_2(v, *p); + return v; +} + +#endif |