DocumentServer/ActiveX/ASCOfficePPTXFile/Editor/CalculatorCRC32.h
nikolay ivanov a8be6b9e72 init repo
2014-07-05 18:22:49 +00:00

119 lines
2.8 KiB
C++

/*
* (c) Copyright Ascensio System SIA 2010-2014
*
* This program is a free software product. You can redistribute it and/or
* modify it under the terms of the GNU Affero General Public License (AGPL)
* version 3 as published by the Free Software Foundation. In accordance with
* Section 7(a) of the GNU AGPL its Section 15 shall be amended to the effect
* that Ascensio System SIA expressly excludes the warranty of non-infringement
* of any third-party rights.
*
* This program is distributed WITHOUT ANY WARRANTY; without even the implied
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. For
* details, see the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
*
* You can contact Ascensio System SIA at Lubanas st. 125a-25, Riga, Latvia,
* EU, LV-1021.
*
* The interactive user interfaces in modified source and object code versions
* of the Program must display Appropriate Legal Notices, as required under
* Section 5 of the GNU AGPL version 3.
*
* Pursuant to Section 7(b) of the License you must retain the original Product
* logo when distributing the program. Pursuant to Section 7(e) we decline to
* grant you any rights under trademark law for use of our trademarks.
*
* All the Product's GUI elements, including illustrations and icon sets, as
* well as technical writing content are licensed under the terms of the
* Creative Commons Attribution-ShareAlike 4.0 International. See the License
* terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode
*
*/
#pragma once
const long g_clFilePartSize = 20*1024;
class CCalculatorCRC32
{
public:
CCalculatorCRC32()
{
m_dwMagicWord = 0xEDB88320;
m_dwInitCrc = 0xFFFFFFFF;
m_bInitTable = FALSE;
}
public:
DWORD Calc(BYTE const*pStream, int nSize)
{
InitCRCTable();
DWORD dwRes = m_dwInitCrc;
for (int i=0;i<nSize;i++)
{
dwRes = m_arCRCTable[(dwRes ^ pStream[i])& 0xFF] ^ (dwRes >> 8);
}
dwRes = dwRes ^ 0xFFFFFFFF;
return dwRes;
}
DWORD Calc(const CString &sStream)
{
InitCRCTable();
DWORD dwRes = m_dwInitCrc;
int nSize = sStream.GetLength();
for (int i=0;i<nSize;i++)
{
dwRes = m_arCRCTable[(dwRes ^ (BYTE)sStream[i]) & 0xFF] ^ (dwRes >> 8);
}
dwRes = dwRes ^ 0xFFFFFFFF;
return dwRes;
}
DWORD CalcPartFile(const CString &sFilepath)
{
DWORD dwRet = 0xFFFFFFFF;
return dwRet;
}
private:
void InitCRCTable()
{
if (m_bInitTable)
return;
DWORD dwTemp;
for (int i=0;i<256;i++)
{
dwTemp = i;
for (int j=0;j<8;j++)
{
if (0x1==(dwTemp & 0x1))
dwTemp = (dwTemp >> 1) ^ m_dwMagicWord;
else
dwTemp = dwTemp >> 1;
}
m_arCRCTable[i] = dwTemp;
}
}
DWORD m_dwMagicWord;
DWORD m_dwInitCrc;
DWORD m_arCRCTable[255];
BOOL m_bInitTable;
};