Defines a buffered file writer.

Objects of this form write data to files using fopen(), fwrite() and fclose(). It is efficient because it reads data in large chunks and then manipulates the internal memory buffer.

A simple usage is shown below:

    CJdlBufferedFileReader rd("in.txt");
    if(rd.Open()) {
      CJdlBufferedFileWriter wr("out.txt");
      if(wr.Open()) {
        char ch;
        while((ch = rd.GetChar())) {
          if('*' == ch) {
            wr.PutChar('$'); // The next GetChar() will return '$'.
          }
          else {
            wr.PutChar(ch);
          }
        }
        wr.Close();
      }
      rd.Close();
    }
 

Author:

Joe Linoff

Version:

$Id: jdlbuffilewr.h,v 1.4 1999/06/12 18:26:00 jdl Exp $

Source:

../../libjdl/src/jdlbuffilewr.h:58

See Also:

CJdlBufferedFileReader

public CJdlBufferedFileWriter ( ) ;

Default Constructor. This allows the class to be used in a has-a relationsip.

Use Open(fn) to set the file name.

public CJdlBufferedFileWriter ( const char * fn ) ;

Constructor.

If the file does not exist, Ok() will return false. The default buffer size is 64K.

public CJdlBufferedFileWriter ( const char * fn ,
                                uint bufsize ) ;

Constructor.

If the file does not exist, Ok() will return false.

public ~ CJdlBufferedFileWriter ( ) ;

Destructor.

public bool Open ( ) ;

Open the file.

The member function was provided so that the same output file could be opened and closed multiple times.

Return:

The status of the open (same as Ok()).

public bool Open ( const char * fn ,
                   uint bufsz = 65535) ) ;

Open the file.

The member function was provided so that the same output file could be opened and closed multiple times.

Return:

The status of the open (same as Ok()).

public bool Ok ( ) const ;

Ok to write?

Return:

true if the file was opened successfully.

public bool Eof ( ) const ;

End of file?

Return:

true if the file was opened successfully, written to and then closed.

public void PutChar ( char ch ) ;

Put a character to the file.

The characters are cached in the internal buffer and when the buffer is full, they are written to the file in one big chunk resulting in faster I/O performance.

public void PutString ( const char * string ) ;

Put a C style string to the file.

The characters are cached in the internal buffer and when the buffer is full, they are written to the file in one big chunk resulting in faster I/O performance.

public void Flush ( ) ;

Flush the contents of the buffer.

public void Close ( ) ;

Close the file.

Flush is automatically called.

After the file is closed, Ok() will return true and Eof() will return true.

public const char * GetFileName ( ) const ;

Return:

The file name.

public long GetLineNumber ( ) const ;

Return:

The current line number.

public uint GetCharOffset ( ) const ;

Returns the offset from the beginning of the line for the current character.

The value returned is as follows:

    "This is a sample line.\n"
     ^    ^                ^
     |    |                +--- CharOffset() == 0
     |    +-------------------- CharOffset() == 6
     +------------------------- CharOffset() == 1
 

Return:

The current character offset from the beginning of the line.

public long GetNumChars ( ) const ;

The total number of characters written.

This number persists after the file is Closed().

Return:

The total number of characters written.

public void Debug ( bool flag = true ) ;

Turn debugging on or off.

This generates a lot of output to stderr so use it sparingly.