/*\
 * $Id: bitio.h,v 1.4 1992/11/24 19:37:02 dws Exp dws $
 *
 * bitio.h - bitstream I/O
 *
 * Works for (sizeof(unsigned long)-1)*8 bits.
 *
 * Copyright (C) 1992 by David W. Sanderson.
 * 
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose and without fee is hereby granted,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  This software is provided "as is"
 * without express or implied warranty.
 *
 * $Log: bitio.h,v $
 * Revision 1.4  1992/11/24  19:37:02  dws
 * Added copyright
 *
 * Revision 1.3  1992/11/17  03:37:59  dws
 * updated comment
 *
 * Revision 1.2  1992/11/10  23:10:22  dws
 * Generalized to handle more than one bitstream at a time.
 *
 * Revision 1.1  1992/11/10  18:33:51  dws
 * Initial revision
 *
\*/

#ifndef _BITIO_H_
#define _BITIO_H_

#include "netpbm/pm.h"

#ifdef __cplusplus
extern "C" {
#endif
#if 0
} /* to fake out automatic code indenters */
#endif

typedef struct bitstream	*BITSTREAM;

struct bitstream *
pm_bitinit(FILE * const f, const char * const mode);

/*
 * pm_bitfini() - deallocate the given BITSTREAM.
 *
 * You must call this after you are done with the BITSTREAM.
 * 
 * It may flush some bits left in the buffer.
 *
 * Returns the number of bytes written, -1 on error.
 */

int
pm_bitfini(BITSTREAM b);

/*
 * pm_bitread() - read the next nbits into *val from the given file.
 * 
 * Returns the number of bytes read, -1 on error.
 */

int
pm_bitread(BITSTREAM       b,
           unsigned long   nbits,
           unsigned long * val);

/*
 * pm_bitwrite() - write the low nbits of val to the given file.
 * 
 * The last pm_bitwrite() must be followed by a call to pm_bitflush().
 * 
 * Returns the number of bytes written, -1 on error.
 */

int
pm_bitwrite(BITSTREAM     b,
            unsigned long nbits,
            unsigned long val);

#ifdef __cplusplus
}
#endif
#endif
