275 lines
6.9 KiB
C++
275 lines
6.9 KiB
C++
//
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// flatfile.h -- This file contains the class definations for:
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// CFlatFile
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//
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// Created:
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// Sep 3, 1996 -- Alex Wetmore (awetmore)
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// Changes:
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// May 7, 1998 -- Alex Wetmore (awetmore)
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// -- Modify for use in NNTP. Remove sorting features, file handle
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// cache, etc.
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// Oct 23,1998 -- Kangrong Yan ( kangyan )
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// -- Added integrity flag
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//
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#ifndef __FLATFILE_H__
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#define __FLATFILE_H__
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#include <windows.h>
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#include <stdio.h>
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#include <writebuf.h>
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//
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// size of the read buffer used for GetFirstRecord/GetNextRecord()
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//
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#define FF_BUFFER_SIZE 8192
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//
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// maximum record size
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//
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#define MAX_RECORD_SIZE 4096
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// do a automatic compaction if there are more then 10 deleted records and
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// the ratio of records to deleted records is less then 10
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#define FF_COMPACTION_MIN_DELETED_RECORDS 10
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#define FF_COMPACTION_MIN_TOTAL_RECORDS 100
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#define FF_COMPACTION_RATIO 10
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//
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// Integrity flag values
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//
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#define FF_FILE_GOOD 0x0000FFFF
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#define FF_FILE_BAD 0x00010000
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//
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// file extensions for flat files
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//
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#define NEW_FF_EXT ".tmp" // extension for new flatfile as its built
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#define BAK_FF_EXT ".bak" // extension for an old backup flatfile
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#define FF_IDX_EXT ".idx" // extension for an index file
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#pragma pack(push, flatfile)
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#pragma pack(1)
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//
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// the structure for the header of the file
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//
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typedef struct {
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DWORD dwSignature; // file signature
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DWORD dwFlags; // file flags
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} FLATFILE_HEADER;
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#define FF_FLAG_COMPACT 0x01
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#define FLATFILE_SIGNATURE (DWORD)'__fF'
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//
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// the record structure for the data file
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//
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// the size of it is RECORD_HEADER_SIZE + cData;
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//
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typedef struct {
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BOOL fDeleted; // is this deleted?
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DWORD cData; // length of the data
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BYTE pData[MAX_RECORD_SIZE]; // data
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} RECORD;
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typedef struct {
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BOOL fDeleted; // is this deleted?
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DWORD cData; // length of the data
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} RECORDHDR;
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#define RECORD_HEADER_SIZE sizeof(RECORDHDR)
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#pragma pack(pop, flatfile)
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//
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// A function of this type will be called whenever a record's offset
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// changes in the flatfile. It is used to keep the owner up to date
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// on record offsets, so that the owner can make quick Delete's
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//
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typedef void (*PFN_OFFSET_UPDATE)(void *pContext, BYTE *pData, DWORD cData, DWORD iNewOffset);
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class CFlatFile {
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public:
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friend class CFlatFileWriteBuf;
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CFlatFile(LPSTR szFilename,
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LPSTR szExtension,
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void *pContext,
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PFN_OFFSET_UPDATE pfnOffsetUpdate,
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DWORD dwSignature = FLATFILE_SIGNATURE,
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BOOL fClear = FALSE,
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DWORD dwFileFlags = 0);
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~CFlatFile();
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// insert a new record into the file
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HRESULT InsertRecord(LPBYTE pData, DWORD cData, DWORD *piOffset = NULL, DWORD dwVer = 0);
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// delete a record from the file
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HRESULT DeleteRecord(DWORD iOffset);
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// compact out any deleted records in the file
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HRESULT Compact();
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// get the first record in the file
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HRESULT GetFirstRecord(LPBYTE pData,
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DWORD *cData,
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DWORD *piByteOffset = NULL,
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DWORD *pdwVer = NULL );
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// get the next record in the file
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HRESULT GetNextRecord(LPBYTE pData,
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DWORD *cData,
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DWORD *piByteOffset = NULL,
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DWORD *pdwVer = NULL);
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// delete everything in the file
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void DeleteAll();
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// Dirty the integrity flag
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HRESULT DirtyIntegrityFlag();
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// Set the integrity flag
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HRESULT SetIntegrityFlag();
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// Is the file in good integrity ?
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BOOL FileInGoodShape();
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// Enable the write buffer
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VOID EnableWriteBuffer( DWORD cbBuffer );
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// Check to see if the file has been opened
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BOOL IsFileOpened();
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private:
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//
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// open/close a file.
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//
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// because this uses cached file handles, the position of the file
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// should not be assumed
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//
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HRESULT OpenFile(LPSTR szFilename = NULL,
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DWORD dwOpenMode = OPEN_ALWAYS,
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DWORD dwFlags = 0);
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//
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// close the file handle
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//
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void CloseFile();
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//
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// set and get the file header
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//
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HRESULT SetFileHeader(FLATFILE_HEADER *pHeader);
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HRESULT GetFileHeader(FLATFILE_HEADER *pHeader);
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//
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// read the next chunk of the file into the temporary buffer
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// used by GetFirstRecord/GetNextRecord()
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//
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HRESULT ReadNextNBytes(LPBYTE pData, DWORD cData);
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HRESULT ReadNBytesFrom(LPBYTE pData, DWORD cData, DWORD iOffset, DWORD *pcDidRead = NULL);
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// iOffset can be set to infinite to append
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HRESULT WriteNBytesTo(LPBYTE pData,
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DWORD cData,
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DWORD *piOffset = NULL,
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DWORD iOffset = INFINITE,
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DWORD *pcDidWrite = NULL);
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HRESULT CFlatFile::WriteNBytesToInternal(
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LPBYTE pData,
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DWORD cData,
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DWORD *piOffset,
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DWORD iOffset,
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DWORD *pcDidWrite);
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HRESULT ReloadReadBuffer();
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//
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// the file handle for this file
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//
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HANDLE m_hFile;
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//
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// flags for creating the file with
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//
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DWORD m_dwFileFlags;
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//
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// filename for the flat file
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//
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char m_szFilename[FILENAME_MAX];
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char m_szBaseFilename[FILENAME_MAX];
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//
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// current read buffer
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//
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BYTE m_pBuffer[FF_BUFFER_SIZE];
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//
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// current offset inside the buffer
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//
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DWORD m_iBuffer;
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//
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// offset of the read buffer in the file
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//
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DWORD m_iFile;
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//
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// size of the read buffer (zero means its not valid)
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//
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DWORD m_cBuffer;
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//
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// clear the file on the next open
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//
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BOOL m_fClearOnOpen;
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//
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// the number of deleted records in the file. this is first
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// computed by FindFirst/FindNext and then kept updated by
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// DeleteRecord and DeleteRecordAtOffset
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//
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DWORD m_cDeletedRecords;
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//
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// the number of records in the file. this is first
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// computed by FindFirst/FindNext and then kept updated by
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// InsertRecord
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//
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DWORD m_cRecords;
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//
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// context passed into callback functions
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//
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void *m_pContext;
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//
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// Whether the file is open
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//
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BOOL m_fOpen;
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//
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// The write buffer
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//
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CFlatFileWriteBuf m_wbBuffer;
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//
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// function to call when an items offset changes in the flatfile
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//
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PFN_OFFSET_UPDATE m_pfnOffsetUpdate;
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//
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// signature for the file
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//
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DWORD m_dwSignature;
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};
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#define ret(__rc__) { /* TraceFunctLeave(); */ return(__rc__); }
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#define retEC(__ec__, __rc__) { SetLastError(__ec__); /* TraceFunctLeave(); */ return(__rc__); }
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#endif
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