release/src/lzma/C/7zCrcT8.c

   1 /* 7zCrcT8.c */
   2
   3 #include "7zCrc.h"
   4
   5 #define kCrcPoly 0xEDB88320
   6 #define CRC_NUM_TABLES 8
   7
   8 UInt32 g_CrcTable[256 * CRC_NUM_TABLES];
   9
  10 void MY_FAST_CALL CrcGenerateTable()
  11 {
  12   UInt32 i;
  13   for (i = 0; i < 256; i++)
  14   {
  15     UInt32 r = i;
  16     int j;
  17     for (j = 0; j < 8; j++)
  18       r = (r >> 1) ^ (kCrcPoly & ~((r & 1) - 1));
  19     g_CrcTable[i] = r;
  20   }
  21   #if CRC_NUM_TABLES > 1
  22   for (; i < 256 * CRC_NUM_TABLES; i++)
  23   {
  24     UInt32 r = g_CrcTable[i - 256];
  25     g_CrcTable[i] = g_CrcTable[r & 0xFF] ^ (r >> 8);
  26   }
  27   #endif
  28 }
  29
  30 UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table);
  31
  32 UInt32 MY_FAST_CALL CrcUpdate(UInt32 v, const void *data, size_t size)
  33 {
  34   return CrcUpdateT8(v, data, size, g_CrcTable);
  35 }
  36
  37 UInt32 MY_FAST_CALL CrcCalc(const void *data, size_t size)
  38 {
  39   return CrcUpdateT8(CRC_INIT_VAL, data, size, g_CrcTable) ^ 0xFFFFFFFF;
  40 }