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

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