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view src/win32/7zip/7z/C/7zCrc.c @ 1:f9f4f1b99eed

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importing src directory
author Robert McIntyre <rlm@mit.edu>
date Sat, 03 Mar 2012 10:31:27 -0600
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     1 /* 7zCrc.c -- CRC32 calculation



     2 2008-08-05



     3 Igor Pavlov



     4 Public domain */



     5 



     6 #include "7zCrc.h"



     7 



     8 #define kCrcPoly 0xEDB88320



     9 UInt32 g_CrcTable[256];



    10 



    11 void MY_FAST_CALL CrcGenerateTable(void)



    12 {



    13   UInt32 i;



    14   for (i = 0; i < 256; i++)



    15   {



    16     UInt32 r = i;



    17     int j;



    18     for (j = 0; j < 8; j++)



    19       r = (r >> 1) ^ (kCrcPoly & ~((r & 1) - 1));



    20     g_CrcTable[i] = r;



    21   }



    22 }



    23 



    24 UInt32 MY_FAST_CALL CrcUpdate(UInt32 v, const void *data, size_t size)



    25 {



    26   const Byte *p = (const Byte *)data;



    27   for (; size > 0 ; size--, p++)



    28     v = CRC_UPDATE_BYTE(v, *p);



    29   return v;



    30 }



    31 



    32 UInt32 MY_FAST_CALL CrcCalc(const void *data, size_t size)



    33 {



    34   return CrcUpdate(CRC_INIT_VAL, data, size) ^ 0xFFFFFFFF;



    35 }