/*****************************************************************************
* bits.h : Bit handling helpers
*****************************************************************************
* Copyright (C) 2003 the VideoLAN team
*
* Authors: Laurent Aimar <fenrir@via.ecp.fr>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*****************************************************************************/
#ifndef BD_BITS_H
#define BD_BITS_H
#include "util/attributes.h"
#include "file/filesystem.h" // BD_FILE_H
#include <stdint.h>
#include <stddef.h> // size_t
/**
* \file
* This file defines functions, structures for handling streams of bits
*/
#define BF_BUF_SIZE (1024*32)
typedef struct {
const uint8_t *p_start;
const uint8_t *p;
const uint8_t *p_end;
int i_left; /* i_count number of available bits */
} BITBUFFER;
typedef struct {
BD_FILE_H *fp;
uint8_t buf[BF_BUF_SIZE];
BITBUFFER bb;
int64_t pos; /* file offset of buffer start (buf[0]) */
int64_t end; /* size of file */
size_t size; /* bytes in buf */
} BITSTREAM;
BD_PRIVATE void bb_init( BITBUFFER *bb, const uint8_t *p_data, size_t i_data );
BD_PRIVATE int bs_init( BITSTREAM *bs, BD_FILE_H *fp ) BD_USED;
BD_PRIVATE void bb_seek( BITBUFFER *bb, int64_t off, int whence);
//BD_PRIVATE void bs_seek( BITSTREAM *bs, int64_t off, int whence);
//BD_PRIVATE void bb_seek_byte( BITBUFFER *bb, int64_t off);
BD_PRIVATE int bs_seek_byte( BITSTREAM *s, int64_t off) BD_USED;
BD_PRIVATE void bb_skip( BITBUFFER *bb, size_t i_count );
BD_PRIVATE void bs_skip( BITSTREAM *bs, size_t i_count ); /* note: i_count must be less than BF_BUF_SIZE */
BD_PRIVATE uint32_t bb_read( BITBUFFER *bb, int i_count );
BD_PRIVATE uint32_t bs_read( BITSTREAM *bs, int i_count );
static inline int64_t bb_pos( const BITBUFFER *bb )
{
return 8 * ( bb->p - bb->p_start ) + 8 - bb->i_left;
}
static inline int64_t bs_pos( const BITSTREAM *bs )
{
return bs->pos * 8 + bb_pos(&bs->bb);
}
static inline int64_t bs_end( const BITSTREAM *bs )
{
return bs->end * 8;
}
static inline int bb_eof( const BITBUFFER *bb )
{
return bb->p >= bb->p_end ? 1: 0 ;
}
/*
static inline int bs_eof( const BITSTREAM *bs )
{
return file_eof(bs->fp) && bb_eof(&bs->bb);
}
*/
static inline int64_t bs_avail( const BITSTREAM *bs )
{
return bs_end(bs) - bs_pos(bs);
}
static inline void bb_read_bytes( BITBUFFER *bb, uint8_t *buf, int i_count )
{
int ii;
for (ii = 0; ii < i_count; ii++) {
buf[ii] = bb_read(bb, 8);
}
}
static inline void bs_read_bytes( BITSTREAM *s, uint8_t *buf, int i_count )
{
int ii;
for (ii = 0; ii < i_count; ii++) {
buf[ii] = bs_read(s, 8);
}
}
static inline void bs_read_string( BITSTREAM *s, char *buf, int i_count )
{
bs_read_bytes(s, (uint8_t*)buf, i_count);
buf[i_count] = '\0';
}
static inline uint32_t bb_show( BITBUFFER *bb, int i_count )
{
BITBUFFER bb_tmp = *bb;
return bb_read( &bb_tmp, i_count );
}
static inline int bb_is_align( BITBUFFER *bb, uint32_t mask )
{
int64_t off = bb_pos(bb);
return !(off & mask);
}
static inline int bs_is_align( BITSTREAM *s, uint32_t mask )
{
int64_t off = bs_pos(s);
return !(off & mask);
}
#endif