xbmemo.h

Go to the documentation of this file.

/*  xbmemo.h
 
XBase64 Software Library
 
Copyright (c) 1997,2003,2014,2022 Gary A Kunkel
 
The xb64 software library is covered under the terms of the GPL Version 3, 2007 license.
 
Email Contact:
 
    XDB-devel@lists.sourceforge.net
    XDB-users@lists.sourceforge.net
 
*/
 
 
#ifndef __XB_XBMEMO_H__
#define __XB_XBMEMO_H__
 
 
// dont use "#pragma interface" with abstract classes
// #ifdef  CMAKE_COMPILER_IS_GNUCC
// #pragma interface
// #endif
 
#ifdef XB_MEMO_SUPPORT
 
 
 
 
namespace xb{
 
 
class XBDLLEXPORT xbMemo : public xbFile {
 public:
 
  xbMemo( xbDbf *dbf, xbString const &sFileName );
 
  /* virtual methods */
  virtual ~xbMemo();
  virtual xbInt16 Abort              () = 0;
  virtual xbInt16 CloseMemoFile      ();
  virtual xbInt16 Commit             () = 0;
 
  #ifdef XB_LOCKING_SUPPORT
  virtual xbInt16 LockMemo           ( xbInt16 iLockFunction );
  virtual xbBool  GetMemoLocked      () const;
  #endif
 
  /* pure virtual methods */
  virtual xbInt16 CreateMemoFile () = 0;
  
  virtual xbInt16 GetMemoField   ( xbInt16 iFieldNo, xbString &sMemoData ) = 0;
  virtual xbInt16 GetMemoFieldLen( xbInt16 iFieldNo, xbUInt32 &ulMemoFieldLen ) = 0;
  virtual xbInt16 OpenMemoFile   () = 0;
  virtual xbInt16 GetMemoFileType();
  virtual xbInt16 PackMemo       ( void (*memoStatusFunc)(xbUInt32 ulItemNum, xbUInt32 ulNumItems)) = 0;
  virtual xbInt16 UpdateMemoField( xbInt16 iFieldNo, const xbString &sMemoData ) = 0;
 
  #ifdef XB_DEBUG_SUPPORT
  virtual xbInt16 DumpMemoFreeChain() = 0;
  virtual xbInt16 DumpMemoHeader () = 0;
  #endif
 
  // *********** FIXME *************
  // next two methods should be protected but are called in the xb_test_xxxx programs testing routines
  // so for now, they are kept as public
  virtual xbInt16 CalcLastDataBlock  ( xbUInt32 &lLastDataBlock );
  virtual xbInt16 GetHdrNextBlock    ( xbUInt32 &ulBlockNo );
 
 protected:
  friend  class   xbDbf;
 
  virtual xbInt16 ReadDbtHeader     ( xbInt16 iOption ) = 0;
  virtual xbInt16 UpdateHeaderName  () = 0;
  virtual xbInt16 UpdateHeadNextNode();
  virtual xbInt16 Zap            () = 0;
 
  xbDbf    *dbf;                 /* pointer to related dbf instance                                   */
  char     cVersion;             /* byte 16 off the header block, 0x03 for V3, version IV - ?         */
  xbInt16  iMemoFileType;        /* 3 = version  III, 4 = version IV                                  */
  xbUInt32 ulHdrNextBlock;       /* next available block , bytes 0-3 of the memo header               */
  void *   mbb;                  /* memo block buffer                                                 */
 
 
 private:
 
  #ifdef XB_LOCKING_SUPPORT
  xbBool bFileLocked;           /* memo file locked */
  #endif
 
};
 
 
 
#ifdef XB_DBF3_SUPPORT
 
class XBDLLEXPORT xbMemoDbt3 : public xbMemo {
 public:
  xbMemoDbt3( xbDbf *dbf, xbString const &sFileName );
  ~xbMemoDbt3();
  virtual xbInt16 Abort          ();
  virtual xbInt16 Commit         ();
  virtual xbInt16 CreateMemoFile ();
  virtual xbInt16 GetMemoField   ( xbInt16 iFieldNo, xbString &sMemoData );
  virtual xbInt16 GetMemoFieldLen( xbInt16 iFieldNo, xbUInt32 &ulMemoFieldLen );
  virtual xbInt16 OpenMemoFile   ();
  virtual xbInt16 PackMemo       ( void (*memoStatusFunc) (xbUInt32 ulItemNum, xbUInt32 ulNumItems));
  virtual xbInt16 UpdateMemoField( xbInt16 iFieldNo, const xbString &sMemoData );
 
  #ifdef XB_DEBUG_SUPPORT
  virtual xbInt16 DumpMemoFreeChain();
  virtual xbInt16 DumpMemoHeader ();
  #endif
 
 protected:
  virtual xbInt16 ReadDbtHeader( xbInt16 iOption );
  virtual xbInt16 UpdateHeaderName();
  virtual xbInt16 Zap();
 
 private:
};
#endif
 
 
#ifdef XB_DBF4_SUPPORT
 
 
class XBDLLEXPORT xbMemoDbt4 : public xbMemo {
 public:
  xbMemoDbt4( xbDbf *dbf, xbString const &sFileName );
  ~xbMemoDbt4();
  virtual xbInt16 Abort              ();
  virtual xbInt16 Commit             ();
  virtual xbInt16 CreateMemoFile     ();
 
  virtual xbInt16 GetMemoField       ( xbInt16 iFieldNo, xbString &sMemoData );
  virtual xbInt16 GetMemoFieldLen    ( xbInt16 iFieldNo, xbUInt32 &ulMemoFieldLen );
  virtual xbInt16 GetMemoFieldLen    ( xbInt16 iFieldNo, xbUInt32 &ulMemoFieldLen, xbUInt32 &lBlockNo );
  virtual xbInt16 OpenMemoFile       ();
  virtual xbInt16 PackMemo           ( void (*memoStatusFunc) (xbUInt32 ulItemNum, xbUInt32 ulNumItems));
  virtual xbInt16 UpdateMemoField    ( xbInt16 iFieldNo, const xbString &sMemoData );
 
  #ifdef XB_DEBUG_SUPPORT
  virtual xbInt16 DumpMemoFreeChain  ();
  virtual xbInt16 DumpMemoHeader     ();
  virtual xbInt16 DumpMemoInternals  ();
  virtual xbInt16 ReadFreeBlockHeader( xbUInt32 ulBlockNo, xbUInt32 &ulNextBlock, xbUInt32 &ulFreeBlockCnt );
  #endif
 
 protected:
  virtual xbInt16 FindBlockSetInChain( xbUInt32 ulBlocksNeeded, xbUInt32 &ulLastDataBlock, xbUInt32 &ulLocation, xbUInt32 &ulPrevNode, xbBool &bFound );
  virtual xbInt16 FreeMemoBlockChain( xbUInt32 ulBlockNo );
  virtual xbInt16 FreeMemoBlockChain( xbUInt32 ulBlockNo, xbUInt32 &ulLastDataBlock );
  virtual xbInt16 GetBlockSetFromChain( xbUInt32 ulBlocksNeeded, xbUInt32 ulLocation, xbUInt32 ulPrevNode );
  virtual xbInt16 ReadDbtHeader( xbInt16 iOption );
  virtual xbInt16 ReadBlockHeader( xbUInt32 ulBlockNo, xbInt16 iOption );
  virtual xbInt16 UpdateHeaderName   ();
  virtual xbInt16 WriteBlockHeader( xbUInt32 ulBlockNo, xbInt16 iOption );
  virtual xbInt16 Zap();
 
 private:
  xbString sDbfFileNameWoExt;
  xbUInt32 ulNextFreeBlock;
  xbUInt32 ulFreeBlockCnt;
  xbInt16  iField1;
  xbInt16  iStartPos;
  xbUInt32 ulFieldLen;
 
  xbLinkList<xbUInt32> llOldBlocks;   // list of previously used memo blocks for field, used by Commit() / Abort()
  xbLinkList<xbUInt32> llNewBlocks;   // list of newly updated memo blocks for field, used by Commit() / Abort()
 
};
#endif
 
 
}        /* namespace xb   */
#endif   /* XB_MEMO_SUPPORT */
#endif   /* __XB_MEMO_H__  */