pl_streambuf.h

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// -*- C++ -*-

// PLearn (A C++ Machine Learning Library)
// Copyright (C) 2002 Xavier Saint-Mleux <saintmlx@iro.umontreal.ca>
//

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// 
//  1. Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
// 
//  2. Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
// 
//  3. The name of the authors may not be used to endorse or promote
//     products derived from this software without specific prior written
//     permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
// OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
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// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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// 
// This file is part of the PLearn library. For more information on the PLearn
// library, go to the PLearn Web site at www.plearn.org

#ifndef pl_streambuf_INC
#define pl_streambuf_INC

//#include <iosfwd>
#include <iostream>
//#include "plerror.h"
#include <plearn/base/PP.h>

namespace PLearn {

using namespace std;

class ioassignstream; //fwd decl.
class pl_streambuf; // fwd decl.
class pl_streammarker; // fwd decl.

class pl_streambuf : public streambuf, public PPointable
{
#if __GNUC__ < 3 && !defined(WIN32)
  typedef int int_type;
  typedef char char_type;
#endif

  static const int_type eof = EOF;

  friend class pl_streammarker;
  friend class ioassignstream;
  
 private:
  typedef streambuf inherited;

 protected:
  
  streambuf& original_buf; //<! original buffer that needs marking
  char* inbuf;             //<! buffer for marking: keeps all chars since first active mark
  int inbuflen;            //<! current length of inbuf
  static const int pback_size= 4;     //<! length of default put back area
  static const int min_buf_size= 16;  //<! minimum buffer size

  pl_streammarker* first_marker;  //<! ptr. to the head of a linked list of active markers

  virtual int_type underflow();   //<! underflow redefined
  virtual int_type uflow();       //<! uflow redefined


  virtual streamsize xsgetn(char* s, streamsize n);
  virtual streamsize xsputn(const char* s, streamsize n);


  virtual int_type overflow(int_type meta = pl_streambuf::eof); //<! overflow redefined
  virtual int_type sync();        //<! sync redefined
  virtual int_type pbackfail(int_type c= eof);  //<! pbackfail redefined

  //inline int curpos() const { return gptr() - inbuf; }  //<! return current position within the input buffer
  // norman: explicit cast:
  inline int curpos() const { return (int)(gptr() - inbuf); }  //<! return current position within the input buffer

public:

  pl_streambuf(streambuf& _original_buf, int_type _inbuflen= 0);
  virtual ~pl_streambuf();

  void seekmark(const pl_streammarker& mark);  //<! reposition input to the marked position

};

class pl_streammarker
{
  friend class pl_streambuf;

 protected:

  pl_streambuf* buf;  //<! marked buffer
  pl_streammarker* next_marker;  //<! next marker for the marked buffer (linked list)
  int pos;            //<! marked position

 public:

  pl_streammarker(pl_streambuf* _buf);  //<! ctor. to mark a pl_streambuf
  pl_streammarker(streambuf* _buf);  //<! ctor. to mark an STL streambuf (...only if it's really a pl_streambuf)

  virtual ~pl_streammarker(); 

};


} // namespace PLearn

#endif //ndef pl_streambuf_INC

---