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121 lines
2.0 KiB
121 lines
2.0 KiB
// (c) 2002 Microsoft Corporation
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// [jorgeba] Jorge Peraza
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#include "StdAfx.h"
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#include "fastfilehash.h"
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CFastFileHash::CFastFileHash(void):m_hFile(0),m_iFileSize(0)
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{
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}
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CFastFileHash::~CFastFileHash(void)
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{
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}
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__int32* CFastFileHash::getHash(TCHAR *sFileName)
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{
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__int32* iHash = NULL;
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if(sFileName==NULL)
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{
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return NULL;
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}
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if(!openFile(sFileName))
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{
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return NULL;
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}
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iHash = calcHash();
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CloseHandle(m_hFile);
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return iHash;
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}
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int CFastFileHash::openFile(TCHAR *sFileName)
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{
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m_hFile = CreateFile(sFileName,GENERIC_READ,FILE_SHARE_READ,NULL,OPEN_ALWAYS,0,NULL);
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if(m_hFile==INVALID_HANDLE_VALUE)
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{
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return FALSE;
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}
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else
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{
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return TRUE;
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}
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}
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__int32* CFastFileHash::calcHash()
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{
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int iFlag = 0;
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int iNdx = 0;
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int iNumOfParts = 0;
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char bFilePart[PART_SIZE];
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__int32* piRes = NULL;
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//Clear common vars
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m_iFileSize = 0;
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//Create the memory for the hash
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piRes = new __int32[5];
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if(piRes==NULL)
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{
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return NULL;
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}
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memset(piRes,0,sizeof(__int32)*5);
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//First, get the size of the file
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m_iFileSize = GetFileSize(m_hFile,NULL);
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iNumOfParts = m_iFileSize / PART_SIZE;
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//Fill the parts buffer
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for(iNdx=0;iNdx<MAX_PARTS;iNdx++)
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{
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//Clear the buffer
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memset(bFilePart,0,PART_SIZE);
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if(iFlag!=1)
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{
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if(!getPart(bFilePart,iNdx))
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{
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iFlag = 1;
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}
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else
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{
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doHash(piRes,bFilePart);
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}
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}
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}
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//Fill the last block with m_iFileSize
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memset(bFilePart,0,PART_SIZE);
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memcpy(bFilePart,&m_iFileSize,sizeof(m_iFileSize));
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doHash(piRes,bFilePart);
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return piRes;
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}
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int CFastFileHash::getPart(char* pBuffer,int iPart)
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{
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int hRes = FALSE;
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DWORD iBytes;
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hRes = ReadFile(m_hFile,pBuffer,PART_SIZE,(LPDWORD) &iBytes,NULL);
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return hRes;
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}
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void CFastFileHash::doHash(__int32* piHash,char* pBuffer)
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{
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for(int iNdx=0;iNdx<5;iNdx++)
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{
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piHash[iNdx] = piHash[iNdx] ^ *((__int32*)pBuffer + iNdx);
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}
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}
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