1 /* 7zCrcOpt.c -- CRC32 calculation 2 2013-11-12 : Igor Pavlov : Public domain */ 3 4 #include "Precomp.h" 5 6 #include "CpuArch.h" 7 8 #define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8)) 9 10 #ifndef MY_CPU_BE 11 12 UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table) 13 { 14 const Byte *p = (const Byte *)data; 15 for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++) 16 v = CRC_UPDATE_BYTE_2(v, *p); 17 for (; size >= 4; size -= 4, p += 4) 18 { 19 v ^= *(const UInt32 *)p; 20 v = 21 table[0x300 + (v & 0xFF)] ^ 22 table[0x200 + ((v >> 8) & 0xFF)] ^ 23 table[0x100 + ((v >> 16) & 0xFF)] ^ 24 table[0x000 + ((v >> 24))]; 25 } 26 for (; size > 0; size--, p++) 27 v = CRC_UPDATE_BYTE_2(v, *p); 28 return v; 29 } 30 31 UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table) 32 { 33 return CrcUpdateT4(v, data, size, table); 34 } 35 36 #endif 37 38 39 #ifndef MY_CPU_LE 40 41 #define CRC_UINT32_SWAP(v) ((v >> 24) | ((v >> 8) & 0xFF00) | ((v << 8) & 0xFF0000) | (v << 24)) 42 43 UInt32 MY_FAST_CALL CrcUpdateT1_BeT4(UInt32 v, const void *data, size_t size, const UInt32 *table) 44 { 45 const Byte *p = (const Byte *)data; 46 for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++) 47 v = CRC_UPDATE_BYTE_2(v, *p); 48 v = CRC_UINT32_SWAP(v); 49 table += 0x100; 50 for (; size >= 4; size -= 4, p += 4) 51 { 52 v ^= *(const UInt32 *)p; 53 v = 54 table[0x000 + (v & 0xFF)] ^ 55 table[0x100 + ((v >> 8) & 0xFF)] ^ 56 table[0x200 + ((v >> 16) & 0xFF)] ^ 57 table[0x300 + ((v >> 24))]; 58 } 59 table -= 0x100; 60 v = CRC_UINT32_SWAP(v); 61 for (; size > 0; size--, p++) 62 v = CRC_UPDATE_BYTE_2(v, *p); 63 return v; 64 } 65 66 #endif 67
