/*---------------------------------------------------------------------------*/// Baseline Wavelet Transform Coder Construction Kit//// Geoff Davis// gdavis@cs.dartmouth.edu// http://www.cs.dartmouth.edu/~gdavis//// Copyright 1996 Geoff Davis 9/11/96//// Permission is granted to use this software for research purposes as// long as this notice stays attached to this software.///*---------------------------------------------------------------------------*/// coder.hh//// Front end to I/O routines for arithmetic coder.  Also has functions// for reading and writing arbitrarily sized integers and individual// bits.//// Note: in the current implementation there is no problem switching// from reading/writing integers/bits to using the arithmetic coder.// However, switching from the arithmetic coder to reading/writing// integers/bits is problematic, since the arithmetic coder keeps a// number of bits in an internal buffer.  This results in a loss of// synchronization and will produce errors.  For this reason we write// all header information requiring the output of integers/bits first// before coding any coefficients.///*---------------------------------------------------------------------------*/#ifndef _CODER_#define _CODER_/*---------------------------------------------------------------------------*/#include <assert.h>#include <iostream.h>#include <iomanip.h>#include "iHisto.h"#include "BitIO.h"#include "Arith.h"#include "IntCoding.hh"/*---------------------------------------------------------------------------*//*---------------------------------------------------------------------------*/class Encoder {public:  BitOut *bitout;  ArithEncoder *arith;  CdeltaEncode *intcoder;  Encoder  (ostream &out, ostream &log=cerr);  ~Encoder ();  // write symbol  void writeSymbol (int symbol, iHistogram *h)              { arith->Encode(h->Count(symbol), h->LeftCount(symbol),			      h->TotalCount()); };    void writePositive (int i)     { intcoder->EncodePositive (i); };  void writeNonneg (int i)       { intcoder->EncodeNonNegative (i); };  void writeInt (int i)          { intcoder->Encode (i); };  void writeBit (int bit)        { bitout->output_bit (bit); }  void writeNBits (int n, int i) { while(n--){writeBit((i&(1 << n))!=0);} };  void flush () { arith->flush (); };  };/*---------------------------------------------------------------------------*//*---------------------------------------------------------------------------*/class Decoder {public:  BitIn *bitin;  ArithDecoder *arith;  CdeltaDecode *intcoder;    Decoder  (istream &in, ostream &log=cerr);  ~Decoder ();    int readSymbol (iHistogram *h)                         { if (arith==NULL) arith = new ArithDecoder(*bitin);                           return arith->Decode(*h); };  int readPositive ()   { return intcoder->DecodePositive (); };  int readNonneg ()     { return intcoder->DecodeNonNegative (); };  int readInt ()        { return intcoder->Decode (); };  int readBit ()        { return bitin->input_bit (); }  int readNBits (int n) { int i = 0; while (n--)                            {i |= readBit()*(1<<n);} return i; }};/*---------------------------------------------------------------------------*/#endif/*---------------------------------------------------------------------------*/