init repo

ActiveX/ASCOfficePPTXFile/Editor/CalculatorCRC32.h

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+/*
+ * (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;
+};