1 /* XzCrc64.c -- CRC64 calculation 2 2011-06-28 : Igor Pavlov : Public domain */ 3 4 #include "Precomp.h" 5 6 #include "XzCrc64.h" 7 #include "CpuArch.h" 8 9 #define kCrc64Poly UINT64_CONST(0xC96C5795D7870F42) 10 11 #ifdef MY_CPU_LE 12 #define CRC_NUM_TABLES 4 13 #else 14 #define CRC_NUM_TABLES 5 15 #define CRC_UINT64_SWAP(v) \ 16 ((v >> 56) | \ 17 ((v >> 40) & ((UInt64)0xFF << 8)) | \ 18 ((v >> 24) & ((UInt64)0xFF << 16)) | \ 19 ((v >> 8) & ((UInt64)0xFF << 24)) | \ 20 ((v << 8) & ((UInt64)0xFF << 32)) | \ 21 ((v << 24) & ((UInt64)0xFF << 40)) | \ 22 ((v << 40) & ((UInt64)0xFF << 48)) | \ 23 (v << 56)) 24 UInt64 MY_FAST_CALL XzCrc64UpdateT1_BeT4(UInt64 v, const void *data, size_t size, const UInt64 *table); 25 #endif 26 27 #ifndef MY_CPU_BE 28 UInt64 MY_FAST_CALL XzCrc64UpdateT4(UInt64 v, const void *data, size_t size, const UInt64 *table); 29 #endif 30 31 typedef UInt64 (MY_FAST_CALL *CRC_FUNC)(UInt64 v, const void *data, size_t size, const UInt64 *table); 32 33 static CRC_FUNC g_Crc64Update; 34 UInt64 g_Crc64Table[256 * CRC_NUM_TABLES]; 35 36 UInt64 MY_FAST_CALL Crc64Update(UInt64 v, const void *data, size_t size) 37 { 38 return g_Crc64Update(v, data, size, g_Crc64Table); 39 } 40 41 UInt64 MY_FAST_CALL Crc64Calc(const void *data, size_t size) 42 { 43 return g_Crc64Update(CRC64_INIT_VAL, data, size, g_Crc64Table) ^ CRC64_INIT_VAL; 44 } 45 46 void MY_FAST_CALL Crc64GenerateTable() 47 { 48 UInt32 i; 49 for (i = 0; i < 256; i++) 50 { 51 UInt64 r = i; 52 unsigned j; 53 for (j = 0; j < 8; j++) 54 r = (r >> 1) ^ (kCrc64Poly & ~((r & 1) - 1)); 55 g_Crc64Table[i] = r; 56 } 57 for (; i < 256 * CRC_NUM_TABLES; i++) 58 { 59 UInt64 r = g_Crc64Table[i - 256]; 60 g_Crc64Table[i] = g_Crc64Table[r & 0xFF] ^ (r >> 8); 61 } 62 63 #ifdef MY_CPU_LE 64 65 g_Crc64Update = XzCrc64UpdateT4; 66 67 68 69 70 71 72 #else 73 { 74 #ifndef MY_CPU_BE 75 UInt32 k = 1; 76 if (*(const Byte *)&k == 1) 77 g_Crc64Update = XzCrc64UpdateT4; 78 else 79 #endif 80 { 81 for (i = 256 * CRC_NUM_TABLES - 1; i >= 256; i--) 82 { 83 UInt64 x = g_Crc64Table[i - 256]; 84 g_Crc64Table[i] = CRC_UINT64_SWAP(x); 85 } 86 g_Crc64Update = XzCrc64UpdateT1_BeT4; 87 } 88 } 89 #endif 90 } 91
