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/*
* Copyright (c) 2001-2002, David Janssens
* Copyright (c) 2003, Yannick Verschueren
* Copyright (c) 2003, Communications and remote sensing Laboratory, Universite catholique de Louvain, Belgium
*
* 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 "bio.h"
#include <stdio.h>
#include <setjmp.h>
static unsigned char *bio_start; /* pointer to the start of the buffer */
static unsigned char *bio_end; /* pointer to the end of the buffer */
static unsigned char *bio_bp; /* pointer to the present position in the buffer */
static unsigned int bio_buf; /* temporary place where each byte is read or written */
static int bio_ct; /* coder : number of bits free to write // decoder : number of bits read */
extern jmp_buf j2k_error;
/*
* Number of bytes written.
*/
int bio_numbytes()
{
return bio_bp - bio_start;
}
/*
* Init encoder.
*
* bp : Output buffer
* len : Output buffer length
*/
void bio_init_enc(unsigned char *bp, int len)
{
bio_start = bp;
bio_end = bp + len;
bio_bp = bp;
bio_buf = 0;
bio_ct = 8;
}
/*
* Init decoder.
*
* bp : Input buffer
* len : Input buffer length
*/
void bio_init_dec(unsigned char *bp, int len)
{
bio_start = bp;
bio_end = bp + len;
bio_bp = bp;
bio_buf = 0;
bio_ct = 0;
}
/*
* Write byte. --> function modified to eliminate longjmp !!!
*
*/
int bio_byteout()
{
bio_buf = (bio_buf << 8) & 0xffff;
bio_ct = bio_buf == 0xff00 ? 7 : 8;
if (bio_bp >= bio_end)
return 1;
*bio_bp++ = bio_buf >> 8;
return 0;
}
/*
* Read byte. --> function modified to eliminate longjmp !!
*
*/
int bio_bytein()
{
bio_buf = (bio_buf << 8) & 0xffff;
bio_ct = bio_buf == 0xff00 ? 7 : 8;
if (bio_bp >= bio_end)
return 1;
bio_buf |= *bio_bp++;
return 0;
}
/*
* Write bit.
*
* b : Bit to write (0 or 1)
*/
void bio_putbit(int b)
{
if (bio_ct == 0) {
bio_byteout();
}
bio_ct--;
bio_buf |= b << bio_ct;
}
/*
* Read bit.
*
*/
int bio_getbit()
{
if (bio_ct == 0) {
bio_bytein();
}
bio_ct--;
return (bio_buf >> bio_ct) & 1;
}
/*
* Write bits.
*
* v : Value of bits
* n : Number of bits to write
*/
void bio_write(int v, int n)
{
int i;
for (i = n - 1; i >= 0; i--) {
bio_putbit((v >> i) & 1);
}
}
/*
* Read bits.
*
* n : Number of bits to read
*/
int bio_read(int n)
{
int i, v;
v = 0;
for (i = n - 1; i >= 0; i--) {
v += bio_getbit() << i;
}
return v;
}
/*
* Flush bits. Modified to eliminate longjmp !!
*
*/
int bio_flush()
{
bio_ct = 0;
if (bio_byteout())
return 1;
if (bio_ct == 7) {
bio_ct = 0;
if (bio_byteout())
return 1;
}
return 0;
}
/*
* Passes the ending bits (coming from flushing)
*/
int bio_inalign()
{
bio_ct = 0;
if ((bio_buf & 0xff) == 0xff) {
if (bio_bytein())
return 1;
bio_ct = 0;
}
return 0;
}
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