82 lines
2.6 KiB
C
82 lines
2.6 KiB
C
/*
|
|
* Copyright (c) 2002-2003, Antonin Descampe
|
|
* 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.
|
|
*/
|
|
|
|
#include "raw.h"
|
|
|
|
|
|
unsigned char raw_c; /* temporary buffer where bits are coded or decoded */
|
|
unsigned int raw_ct; /* number of bits already read or free to write */
|
|
unsigned int raw_lenmax; /* maximum length to decode */
|
|
unsigned int raw_len; /* length decoded */
|
|
unsigned char *raw_bp; /* pointer to the current position in the buffer */
|
|
unsigned char *raw_start; /* pointer to the start of the buffer */
|
|
unsigned char *raw_end; /* pointer to the end of the buffer */
|
|
|
|
/*
|
|
* Return the number of bytes already encoded.
|
|
*/
|
|
int raw_numbytes()
|
|
{
|
|
return raw_bp - raw_start;
|
|
}
|
|
|
|
/*
|
|
* Initialize raw-decoder.
|
|
*
|
|
* bp : pointer to the start of the buffer from which the bytes will be read
|
|
* len : length of the input buffer
|
|
*/
|
|
void raw_init_dec(unsigned char *bp, int len)
|
|
{
|
|
raw_start = bp;
|
|
raw_lenmax = len;
|
|
raw_len = 0;
|
|
raw_c = 0;
|
|
raw_ct = 0;
|
|
}
|
|
|
|
/*
|
|
* Decode a symbol using raw-decoder. Cfr p.506 TAUBMAN
|
|
*/
|
|
int raw_decode()
|
|
{
|
|
int d;
|
|
if (raw_ct == 0) {
|
|
raw_ct = 8;
|
|
if (raw_len == raw_lenmax)
|
|
raw_c = 0xff;
|
|
else {
|
|
if (raw_c == 0xff)
|
|
raw_ct = 7;
|
|
raw_c = *(raw_start + raw_len);
|
|
raw_len++;
|
|
}
|
|
}
|
|
raw_ct--;
|
|
d = (raw_c >> raw_ct) & 0x01;
|
|
return d;
|
|
}
|