//===========================================================================
//  Copyright (C) 1999 Matt Timmermans
//  Free for non-commercial purposes as long as this notice remains intact.
//  To discuss commercial use, mail me at matt@timmermans.org
//
//  trivial.h
//
//  These classes implement a simple bijection between byte streams and
//  "finitely odd" bit streams, where a finitely odd bit stream is of infinite
//  length, but the position of the rightmost 1 bit is finite, i.e., there
//  is a final 1 bit somewhere in the stream, which is followed by an infinite
//  number of zero bits
//
//===========================================================================

#ifndef wddstx1afsvbsxtpezmxgvut0q4ehncy
#define wddstx1afsvbsxtpezmxgvut0q4ehncy


#include "mtstream.h"

//===========================================================================
//  TrivialFOEncoder: encode bytes to FO.  The byte stream must be an even
//    number of blocklen sized blocks
//===========================================================================

class TrivialFOEncoder : public IOByteSource
  {
  public:
  TrivialFOEncoder(unsigned blocklen=1)
    {
    m_blocklen=(blocklen?blocklen:1);
    m_reserved0=m_done=false;
    }
  TrivialFOEncoder
    (IOByteSource *source,bool autodelete=false,unsigned blocklen=1)
    {
    m_blocklen=(blocklen?blocklen:1);
    m_reserved0=m_done=false;
    SetSource(source,autodelete);
    }
  ~TrivialFOEncoder()
    {Clear();}

  void SetSource(IOByteSource *source,bool autodelete=false)
    {Clear();m_in.SetSource(source,autodelete);}

  void Clear()
    {
    m_in.Clear();
    m_reserved0=m_done=false;
    }

  public: //from IOByteSource

  virtual bool FillQ(IOByteQ *dest);

  private:
  ByteStream m_in;
  unsigned m_blocklen,m_taillen;
  BYTE m_tail[16];
  bool m_reserved0,m_done;
  };


//===========================================================================
//  TrivialFODecoder: Decode FO into byte blocks
//===========================================================================

class TrivialFODecoder : public IOByteSource
  {
  public:
  TrivialFODecoder(unsigned blocklen=1)
    {
    m_blocklen=(blocklen?blocklen:1);
    m_reserved0=m_done=false;
    }
  TrivialFODecoder
    (IOByteSource *source,bool autodelete=false,unsigned blocklen=1)
    {
    m_blocklen=(blocklen?blocklen:1);
    m_reserved0=m_done=false;
    SetSource(source,autodelete);
    }
  ~TrivialFODecoder()
    {Clear();}

  void SetSource(IOByteSource *source,bool autodelete=false)
    {Clear();m_in.SetSource(source,autodelete);}

  void Clear()
    {
    m_in.Clear();
    m_reserved0=m_done=false;
    }

  public: //from IOByteSource

  virtual bool FillQ(IOByteQ *dest);

  private:
  FOStream m_in;
  unsigned m_blocklen;
  bool m_reserved0,m_done;
  };


#endif