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/*
* CRC.cpp
*
* This file is a part of LZMA compression module for NSIS.
*
* Original LZMA SDK Copyright (C) 1999-2006 Igor Pavlov
* Modifications Copyright (C) 2003-2018 Amir Szekely <kichik@netvision.net.il>
*
* Licensed under the Common Public License version 1.0 (the "License");
* you may not use this file except in compliance with the License.
*
* Licence details can be found in the file COPYING.
*
* This software is provided 'as-is', without any express or implied
* warranty.
*
* Reviewed for Unicode support by Jim Park -- 08/28/2007
*/
#include "StdAfx.h"
#include "CRC.h"
static const UInt32 kCRCPoly = 0xEDB88320;
UInt32 CCRC::Table[256];
void CCRC::InitTable()
{
for (UInt32 i = 0; i < 256; i++)
{
UInt32 r = i;
for (int j = 0; j < 8; j++)
if (r & 1)
r = (r >> 1) ^ kCRCPoly;
else
r >>= 1;
CCRC::Table[i] = r;
}
}
class CCRCTableInit
{
public:
CCRCTableInit() { CCRC::InitTable(); }
} g_CRCTableInit;
void CCRC::UpdateByte(Byte b)
{
_value = Table[((Byte)(_value)) ^ b] ^ (_value >> 8);
}
void CCRC::UpdateUInt16(UInt16 v)
{
UpdateByte(Byte(v));
UpdateByte(Byte(v >> 8));
}
void CCRC::UpdateUInt32(UInt32 v)
{
for (int i = 0; i < 4; i++)
UpdateByte((Byte)(v >> (8 * i)));
}
void CCRC::UpdateUInt64(UInt64 v)
{
for (int i = 0; i < 8; i++)
UpdateByte((Byte)(v >> (8 * i)));
}
void CCRC::Update(const void *data, size_t size)
{
UInt32 v = _value;
const Byte *p = (const Byte *)data;
for (; size > 0 ; size--, p++)
v = Table[((Byte)(v)) ^ *p] ^ (v >> 8);
_value = v;
}
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