source: main/branches/64_bit_Greenstone/greenstone2/common-src/indexers/mg/lib/bitio_random.h@ 23508

/**************************************************************************
 *
 * bitio_random.h -- Functions for bitio to a file (random access)
 * Copyright (C) 1994  Neil Sharman
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 **************************************************************************
 *
 *  This file contains function definitions for doing bitwise input and output
 *  of numbers on an array of chars. These routines are slower than the ones 
 *  in "mem" files. but with these routines you can mix reads and writes, or 
 *  multiple writes,  on the array of chars at the same time and guarantee
 *  them to work, also you can seek to a point and do a write. The decode and 
 *  encode functions cannot detect when the end off the character is reached
 *  and just continue processing.
 *
 *  Modified:
 *   - long long seek and tell ops
 *     (1999-08-03 Tim Bell <[email protected]>)
 **************************************************************************/

#ifndef H_BITIO_RANDOM
#define H_BITIO_RANDOM

#include "longlong.h"


typedef struct random_bitio_state
  {
    FILE *File;
    unsigned char *Buf;
    mg_u_long Base;
    mg_u_long Used;
    mg_u_long pos;
    mg_u_long len;
    mg_u_long sft;
  }
random_bitio_state;


/* NOTE : All bytes are filled high bit first */


void BIO_Random_Start (FILE * f, mg_u_long len,
               random_bitio_state * bs);
void BIO_Random_Done (random_bitio_state * bs);



void BIO_Random_Decode_Start (void *buf, mg_u_long pos,
                  random_bitio_state * bs);

void BIO_Random_Encode_Bit (int bit, random_bitio_state * bs);

int BIO_Random_Decode_Bit (random_bitio_state * bs);


void BIO_Random_Unary_Encode (mg_u_long val, random_bitio_state * bs,
                  mg_u_long *bits);
mg_u_long BIO_Random_Unary_Decode (random_bitio_state * bs,
                       mg_u_long *bits);



void BIO_Random_Binary_Encode (mg_u_long val, mg_u_long b,
                   random_bitio_state * bs, mg_u_long *bits);
mg_u_long BIO_Random_Binary_Decode (mg_u_long b, random_bitio_state * bs,
                    mg_u_long *bits);



void BIO_Random_Gamma_Encode (mg_u_long val, random_bitio_state * bs,
                  mg_u_long *bits);
mg_u_long BIO_Random_Gamma_Decode (random_bitio_state * bs,
                       mg_u_long *bits);



void BIO_Random_Delta_Encode (mg_u_long val, random_bitio_state * bs,
                  mg_u_long *bits);
mg_u_long BIO_Random_Delta_Decode (random_bitio_state * bs,
                       mg_u_long *bits);


void BIO_Random_Elias_Encode (mg_u_long val, mg_u_long b, double s,
                  random_bitio_state * bs, mg_u_long *bits);
mg_u_long BIO_Random_Elias_Decode (mg_u_long b, double s,
                       random_bitio_state * bs,
                       mg_u_long *bits);


void BIO_Random_Bblock_Encode (mg_u_long val, mg_u_long b,
                   random_bitio_state * bs, mg_u_long *bits);
mg_u_long BIO_Random_Bblock_Decode (mg_u_long b,
                    random_bitio_state * bs,
                    mg_u_long *bits);


void BIO_Random_Seek (mg_u_long pos, random_bitio_state * bs);

void BIO_Random_Flush (random_bitio_state * bs);

mg_u_long BIO_Random_Tell (random_bitio_state * bs);

#ifdef USE_LONG_LONG

void BIO_Random_Seek_LL (mg_ullong pos, random_bitio_state * bs);
mg_ullong BIO_Random_Tell_LL (random_bitio_state * bs);

#endif /* USE_LONG_LONG */

#endif