openjpeg/libopenjpeg/bio.c

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2003-11-27 11:10:17 +01:00
/*
* 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, *bio_end, *bio_bp;
static unsigned int bio_buf;
static int bio_ct;
extern jmp_buf j2k_error;
/* <summary> */
/* Number of bytes written. */
/* </summary> */
int bio_numbytes()
{
return bio_bp - bio_start;
}
/* <summary> */
/* Init encoder. */
/* </summary> */
/* <param name="bp">Output buffer</param> */
/* <param name="len">Output buffer length</param> */
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;
}
/* <summary> */
/* Init decoder. */
/* </summary> */
/* <param name="bp">Input buffer</param> */
/* <param name="len">Input buffer length</param> */
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;
}
/* <summary> */
/* Write byte. --> function modified to eliminate longjmp !!! */
/* </summary> */
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;
}
/* <summary> */
/* Read byte. --> function modified to eliminate longjmp !! */
/* </summary> */
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;
}
/* <summary> */
/* Write bit. */
/* </summary> */
/* <param name="b">Bit to write (0 or 1)</param> */
void bio_putbit(int b)
{
if (bio_ct == 0) {
bio_byteout();
}
bio_ct--;
bio_buf |= b << bio_ct;
}
/* <summary> */
/* Read bit. */
/* </summary> */
int bio_getbit()
{
if (bio_ct == 0) {
bio_bytein();
}
bio_ct--;
return (bio_buf >> bio_ct) & 1;
}
/* <summary> */
/* Write bits. */
/* </summary> */
/* <param name="v">Value of bits</param> */
/* <param name="n">Number of bits to write</param> */
void bio_write(int v, int n)
{
int i;
for (i = n - 1; i >= 0; i--) {
bio_putbit((v >> i) & 1);
}
}
/* <summary> */
/* Read bits. */
/* </summary> */
/* <param name="n">Number of bits to read</param> */
int bio_read(int n)
{
int i, v;
v = 0;
for (i = n - 1; i >= 0; i--) {
v += bio_getbit() << i;
}
return v;
}
/* <summary> */
/* Flush bits. MOdified to eliminate longjmp !! */
/* </summary> */
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;
}
/* <summary> */
/* </summary> */
int bio_inalign()
{
bio_ct = 0;
if ((bio_buf & 0xff) == 0xff) {
if (bio_bytein())
return 1;
bio_ct = 0;
}
return 0;
}