www.pudn.com > RSImageManger.rar > DATASRC.H

/* 
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|      $id$ 
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|      Copyright (c) 1996-1998 Ulrich von Zadow 
| 
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*/ 
 
#ifndef INCL_DATASRC 
#define INCL_DATASRC 
 
#include "except.h" 
 
class IProgressNotification; 
 
//! This is a base class for a source of picture data. 
//! It defines methods to open, close, and read from data sources. 
//! Does byte-order-conversions in the ReadByte, ReadWord, and 
//! ReadLong routines. 
class CDataSource : public CPLObject 
{ 
 
public: 
 
  //! 
  CDataSource 
    ( IProgressNotification * pNotification = NULL 
    ); 
 
  //! 
  virtual ~CDataSource 
    (); 
 
  //! 
  virtual void Open 
    ( const char * pszName, 
      int    FileSize 
    ); 
 
  //! 
  virtual void Close 
    (); 
 
  //! 
  char * GetName 
    (); 
 
  //! Read but don't advance file pointer. 
  virtual BYTE * GetBufferPtr 
    ( int MinBytesInBuffer 
    ) = 0; 
 
  //! This needs to be overridden in derived classes. 
  virtual BYTE * ReadNBytes 
    ( int n 
    ); 
 
  //! 
  int GetFileSize 
    (); 
 
  //! This is a legacy routine that interferes with progress notifications. 
  //! Don't call it! 
  virtual BYTE * ReadEverything 
    () = 0; 
 
  //! 
  BYTE * Read1Byte 
    (); 
 
  //! 
  BYTE * Read2Bytes 
    (); 
 
  //! 
  BYTE * Read4Bytes 
    (); 
 
  // JH 15.4.99: 
  //! handles progress notification from other libs 
  void OProgressNotification 
    ( double part 
    ); 
 
  //! 
  void AlignToWord 
    (); 
 
  //! 
  void Skip 
    ( int n 
    ); 
 
  //! Test to see if we didn't go past the end of the file 
  void CheckEOF 
    (); 
 
protected: 
 
private: 
  char * m_pszName;        // Name of the data source for diagnostic 
                           // purposes. 
  int    m_FileSize; 
  int    m_BytesRead; 
  BOOL   m_bSrcLSBFirst;   // Source byte order: TRUE for intel order, 
                           // FALSE for Motorola et al. (MSB first). 
  IProgressNotification * m_pNotification; 
}; 
 
 
inline int CDataSource::GetFileSize 
    () 
{ 
  return m_FileSize; 
} 
 
inline BYTE * CDataSource::Read1Byte 
    () 
{ 
  return ReadNBytes (1); 
} 
 
 
inline BYTE * CDataSource::Read2Bytes 
    () 
{ 
  return ReadNBytes (2); 
} 
 
 
inline BYTE * CDataSource::Read4Bytes 
    () 
{ 
  return ReadNBytes (4); 
} 
 
inline void CDataSource::AlignToWord 
    () 
{ 
  if (m_BytesRead & 1) 
    Read1Byte(); 
} 
 
 
inline void CDataSource::Skip 
    ( int n 
    ) 
{ 
  ReadNBytes (n); 
} 
 
inline void CDataSource::CheckEOF 
    () 
{ 
 
  if (m_FileSize < m_BytesRead) 
  { 
    throw CTextException (ERR_END_OF_FILE, 
          "End of file reached while decoding.\n"); 
  } 
} 
 
#endif 
/* 
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