openjpeg/libopenjpeg/bio.h

/*
 * Copyright (c) 2002-2007, Communications and Remote Sensing Laboratory, Universite catholique de Louvain (UCL), Belgium
 * Copyright (c) 2002-2007, Professor Benoit Macq
 * Copyright (c) 2001-2003, David Janssens
 * Copyright (c) 2002-2003, Yannick Verschueren
 * Copyright (c) 2003-2007, Francois-Olivier Devaux and Antonin Descampe
 * Copyright (c) 2005, Herve Drolon, FreeImage Team
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `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 NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __BIO_H
#define __BIO_H

#include <stddef.h> /* ptrdiff_t */

/** 
@file bio.h
@brief Implementation of an individual bit input-output (BIO)

The functions in BIO.C have for goal to realize an individual bit input - output.
*/

/** @defgroup BIO BIO - Individual bit input-output stream */
/*@{*/

/**
Individual bit input-output stream (BIO)
*/
typedef struct opj_bio {
	/** pointer to the start of the buffer */
	unsigned char *start;
	/** pointer to the end of the buffer */
	unsigned char *end;
	/** pointer to the present position in the buffer */
	unsigned char *bp;
	/** temporary place where each byte is read or written */
	unsigned int buf;
	/** coder : number of bits free to write. decoder : number of bits read */
	int ct;
} opj_bio_t;

/** @name Exported functions */
/*@{*/
/* ----------------------------------------------------------------------- */
/**
Create a new BIO handle 
@return Returns a new BIO handle if successful, returns NULL otherwise
*/
opj_bio_t* bio_create(void);
/**
Destroy a previously created BIO handle
@param bio BIO handle to destroy
*/
void bio_destroy(opj_bio_t *bio);
/**
Number of bytes written.
@param bio BIO handle
@return Returns the number of bytes written
*/
ptrdiff_t bio_numbytes(opj_bio_t *bio);
/**
Init encoder
@param bio BIO handle
@param bp Output buffer
@param len Output buffer length 
*/
void bio_init_enc(opj_bio_t *bio, unsigned char *bp, int len);
/**
Init decoder
@param bio BIO handle
@param bp Input buffer
@param len Input buffer length 
*/
void bio_init_dec(opj_bio_t *bio, unsigned char *bp, int len);
/**
Write bits
@param bio BIO handle
@param v Value of bits
@param n Number of bits to write
*/
void bio_write(opj_bio_t *bio, int v, int n);
/**
Read bits
@param bio BIO handle
@param n Number of bits to read 
@return Returns the corresponding read number
*/
int bio_read(opj_bio_t *bio, int n);
/**
Flush bits
@param bio BIO handle
@return Returns 1 if successful, returns 0 otherwise
*/
int bio_flush(opj_bio_t *bio);
/**
Passes the ending bits (coming from flushing)
@param bio BIO handle
@return Returns 1 if successful, returns 0 otherwise
*/
int bio_inalign(opj_bio_t *bio);
/* ----------------------------------------------------------------------- */
/*@}*/

/*@}*/

#endif /* __BIO_H */