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/****************************************************************************
* Copyright (C) 2009-2015 EPAM Systems
*
* This file is part of Indigo toolkit.
*
* This file may be distributed and/or modified under the terms of the
* GNU General Public License version 3 as published by the Free Software
* Foundation and appearing in the file LICENSE.GPL included in the
* packaging of this file.
*
* This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
* WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
***************************************************************************/
#include <string.h>
#include "base_c/defs.h"
#include "base_cpp/crc32.h"
using namespace indigo;
CRC32 _crc; // singletone
unsigned _Reflect (unsigned ref, char ch)
{
unsigned value = 0;
// swap bits 0-7, 1-6, ...
for (int i = 1; i <= ch; i++)
{
if(ref & 1)
value |= 1 << (ch - i);
ref >>= 1;
}
return value;
}
CRC32::CRC32 ()
{
int i, polynom = 0x04c11db7; // used in PKZip, WinZip, and Ethernet.
for (i = 0; i < 256; i++)
{
_table[i] = _Reflect(i, 8) << 24;
for (int j = 0; j < 8; j++)
_table[i] = (_table[i] << 1) ^ (_table[i] & (1 << 31) ? polynom : 0);
_table[i] = _Reflect(_table[i], 32);
}
}
CRC32::~CRC32 ()
{
}
unsigned CRC32::get (const char *text)
{
unsigned code = 0xffffffff;
while (*text != 0)
{
code = (code >> 8) ^ _crc._table[(code & 0xFF) ^ ((byte)*text)];
text++;
}
return code ^ 0xffffffff;
}
unsigned CRC32::get (const char *text, int len)
{
unsigned code = 0xffffffff;
for (int i = 0; i < len; i++)
code = (code >> 8) ^ _crc._table[(code & 0xFF) ^ ((byte)text[i])];
return code ^ 0xffffffff;
}
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