arithm.h

常用的无损压缩算法源代码

/* = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = */

/*     A R I T H M E T I C   C O D E   I M P L E M E N T A T I O N     */

/* = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = */
/*     > > > > >    ANSI C version  4.03  -  05/30/95    < < < < <     */

/*   Amir Said - [e-mail]                            */
/*   Faculty of Electrical Engineering                                 */
/*   University of Campinas (UNICAMP) - Campinas, SP 13081, Brazil     */

/*   William A. Pearlman - [e-mail]                       */
/*   Dept. of Electrical, Computer, and Systems Engineering            */
/*   Rensselaer Polytechnic Institute - Troy, NY 12180, USA            */


/* - - Inclusion - - - - - - - - - - - - - - - - - - - - - - - - - - - */

#include <stdlib.h>
#include <stdio.h>


/* - - External definitions  - - - - - - - - - - - - - - - - - - - - - */

#define MaxSymbols 257


/* - - Data types  - - - - - - - - - - - - - - - - - - - - - - - - - - */

typedef struct {

  int numb_symb, * freq, * cum_freq, * index_to_symb, * symb_to_index;

} Adaptive_Model;


typedef struct {

  FILE * out_file;
  int bit_buffer, bit_index, bits_to_follow;
  long low, high, byte_counter;

} Encoder;


typedef struct {

  FILE * in_file;
  int bit_buffer, bit_index, extra_bits;
  long low, high, value, byte_counter;

} Decoder;


/* - - Interface to < Adaptive_Model > - - - - - - - - - - - - - - - - */

void Create_Model(Adaptive_Model * M, int numb_symb);

void Reset_Model(Adaptive_Model * M);

void Set_New_Model(Adaptive_Model * M, int numb_symb);

void Dispose_Model(Adaptive_Model * M);


/* - - Interface to < Encoder >  - - - - - - - - - - - - - - - - - - - */

void Start_Encoder(Encoder * E, char * file_name);

long Stop_Encoder(Encoder * E);

void Write_Symbol(Encoder * E, Adaptive_Model * M, int symb);

void Write_Bits(Encoder * E, int bits, int word);

long Bytes_Used(Encoder * E);


/* - - Interface to < Arithm_Decoder > - - - - - - - - - - - - - - - - */

void Start_Decoder(Decoder * D, char * file_name);

void Stop_Decoder(Decoder * E);

int Read_Symbol(Decoder * D, Adaptive_Model * M);

int Read_Bits(Decoder * E, int bits);

long Bytes_Read(Decoder * E);


/* = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = */

/* end of file < arithm.h > */