CPP/7zip/Compress/BZip2Crc.cpp


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// BZip2Crc.cpp

#include "StdAfx.h"

#include "BZip2Crc.h"

UInt32 CBZip2Crc::Table[256];

static const UInt32 kBZip2CrcPoly = 0x04c11db7;  /* AUTODIN II, Ethernet, & FDDI */

void CBZip2Crc::InitTable()
{
  for (UInt32 i = 0; i < 256; i++)
  {
    UInt32 r = (i << 24);
    for (unsigned j = 0; j < 8; j++)
      r = (r << 1) ^ (kBZip2CrcPoly & ((UInt32)0 - (r >> 31)));
    Table[i] = r;
  }
}

static
class CBZip2CrcTableInit
{
public:
  CBZip2CrcTableInit() { CBZip2Crc::InitTable(); }
} g_BZip2CrcTableInit;