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 }