91 lines
2.6 KiB
C++
91 lines
2.6 KiB
C++
/*
|
|
* (c) Copyright Ascensio System SIA 2010-2023
|
|
*
|
|
* 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 20A-6 Ernesta Birznieka-Upish
|
|
* street, Riga, Latvia, EU, LV-1050.
|
|
*
|
|
* 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
|
|
*
|
|
*/
|
|
#ifndef _ASC_COMMON_CALCULATOR_CRC32_
|
|
#define _ASC_COMMON_CALCULATOR_CRC32_
|
|
|
|
#include <string>
|
|
|
|
const int g_clFilePartSize = 20 * 1024;
|
|
class CCalculatorCRC32
|
|
{
|
|
public:
|
|
CCalculatorCRC32()
|
|
{
|
|
m_dwMagicWord = 0xEDB88320;
|
|
m_dwInitCrc = 0xFFFFFFFF;
|
|
m_bInitTable = false;
|
|
}
|
|
|
|
public:
|
|
unsigned int Calc(const unsigned char* pStream, unsigned int nSize)
|
|
{
|
|
InitCRCTable();
|
|
unsigned int dwRes = m_dwInitCrc;
|
|
for (unsigned int i = 0; i < nSize; i++)
|
|
{
|
|
dwRes = m_arCRCTable[(dwRes ^ pStream[i]) & 0xFF] ^ (dwRes >> 8);
|
|
}
|
|
|
|
dwRes = dwRes ^ 0xFFFFFFFF;
|
|
return dwRes;
|
|
}
|
|
|
|
private:
|
|
void InitCRCTable()
|
|
{
|
|
if (m_bInitTable)
|
|
return;
|
|
|
|
unsigned int 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;
|
|
}
|
|
m_bInitTable = true;
|
|
}
|
|
|
|
unsigned int m_dwMagicWord;
|
|
unsigned int m_dwInitCrc;
|
|
unsigned int m_arCRCTable[255];
|
|
bool m_bInitTable;
|
|
};
|
|
|
|
#endif // _ASC_COMMON_CALCULATOR_CRC32_
|