asyncwriter.h

VHPD1394 V1.15驅動程序源碼

/************************************************************************
 *  THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
 *  KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
 *  PURPOSE.
 ************************************************************************/

/************************************************************************
 *
 *  Module:       AsyncWriter.h
 *  Long name:    CAsyncWriter class definition
 *  Description:  Simple class that continuously transmits data using 
 *                asynchronous WRITE requests (based on CVhpdAsyncWriter).
 *
 *  Runtime Env.: Win32
 *  Author(s):    Frank Senf
 *  Company:      Thesycon GmbH, Ilmenau
 ************************************************************************/

#if !defined(_ASYNCWRITER_h_)
#define _ASYNCWRITER_h_


// get base class definition
#include "CVhpdAsyncWriter.h"

//
// CAsyncWriter class
// The class is derived from the CVhpdAsyncWriter class contained in the
// VHPDLib C++ class library.
// Thus, it has an embeded worker thread that handles data transmission.
// The class mainly implements the ProcessBuffer function defined
// by the base class.
//
class CAsyncWriter : public CVhpdAsyncWriter {

public:
  // Construction
  CAsyncWriter();
  // destructor
  ~CAsyncWriter();

  // ----------------
  // interface

  // source file handling
  // opens the specified file
  // returns 0 for success, 1 if a file was already opened or an specific
  // error code if opening the file failed
  unsigned long
  OpenFile(const char *Filename);
  // closes the source file, no-op if no file is currently opened
  void CloseFile();

  // return current number of buffers completed with error
  unsigned long
  GetErrorCount() { return m_BufferError; }

  // return status code of last buffer completed with error
  unsigned long
  GetLastError() { return m_LastError; }

  // returns true if the thread is about to terminate
  bool
  ThreadExited() { return m_ThreadExited; }

  // ----------------
  // CVhpdThread overloaded functions

  // This notification handler is called in the context of
  // the worker thread before the thread terminates itself.
  // NOTE: It is called in the context of the worker thread.
  virtual
  void OnThreadExit();

  // overloaded CVhpdThread::TerminateThread() function
  // NOTE 1: called in the context of the main thread
  // NOTE 2: TerminateThread() is overloaded to ensure that the
  // thread will exit. This is done by trying to terminate the
  // thread until it really terminates. For future version of VHPDLib
  // this will be implemented by the base class
  virtual
  void 
  TerminateThread();


// implementation
protected:

  // --------------
  // CVhpdAsyncWriter overloaded functions

  // function that fills the buffer with data
  // returns FALSE if buffer processing should be stopped, TRUE to continue
  virtual
  BOOL ProcessBuffer(CVhpdBuf* Buf);
  
  // function is called if a buffer was completed by the driver with error
  virtual
  void BufErrorHandler(CVhpdBuf* Buf);

  // --------------
  // member variables

  // input file, NULL if not valid
  HANDLE m_File;
  // pattern will be filled to buffer before transferring, only used if m_File==NULL
  unsigned char m_Pattern;

  // flag is set to true if OnThreadExit is called
  bool m_ThreadExited;

  // error handling
  // counter increases every time a buffer is completed with an error status
  unsigned long m_BufferError;
  // last error received from the Buf->mStatus member, only valid if
  // m_BufferError != 0
  unsigned long m_LastError;

};


#endif // !defined(_ASYNCWRITER_h_)

/*************************** EOF **************************************/