195 lines
4.0 KiB
C
195 lines
4.0 KiB
C
/*
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* Copyright (c) 2001-2002, David Janssens
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* Copyright (c) 2003, Yannick Verschueren
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* Copyright (c) 2003, Communications and remote sensing Laboratory, Universite catholique de Louvain, Belgium
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "bio.h"
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#include <stdio.h>
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#include <setjmp.h>
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static unsigned char *bio_start; /* pointer to the start of the buffer */
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static unsigned char *bio_end; /* pointer to the end of the buffer */
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static unsigned char *bio_bp; /* pointer to the present position in the buffer */
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static unsigned int bio_buf; /* temporary place where each byte is read or written */
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static int bio_ct; /* coder : number of bits free to write // decoder : number of bits read */
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extern jmp_buf j2k_error;
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/*
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* Number of bytes written.
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*/
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int bio_numbytes()
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{
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return bio_bp - bio_start;
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}
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/*
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* Init encoder.
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*
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* bp : Output buffer
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* len : Output buffer length
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*/
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void bio_init_enc(unsigned char *bp, int len)
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{
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bio_start = bp;
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bio_end = bp + len;
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bio_bp = bp;
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bio_buf = 0;
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bio_ct = 8;
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}
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/*
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* Init decoder.
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*
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* bp : Input buffer
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* len : Input buffer length
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*/
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void bio_init_dec(unsigned char *bp, int len)
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{
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bio_start = bp;
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bio_end = bp + len;
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bio_bp = bp;
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bio_buf = 0;
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bio_ct = 0;
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}
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/*
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* Write byte. --> function modified to eliminate longjmp !!!
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*
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*/
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int bio_byteout()
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{
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bio_buf = (bio_buf << 8) & 0xffff;
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bio_ct = bio_buf == 0xff00 ? 7 : 8;
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if (bio_bp >= bio_end)
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return 1;
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*bio_bp++ = bio_buf >> 8;
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return 0;
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}
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/*
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* Read byte. --> function modified to eliminate longjmp !!
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*
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*/
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int bio_bytein()
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{
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bio_buf = (bio_buf << 8) & 0xffff;
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bio_ct = bio_buf == 0xff00 ? 7 : 8;
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if (bio_bp >= bio_end)
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return 1;
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bio_buf |= *bio_bp++;
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return 0;
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}
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/*
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* Write bit.
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*
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* b : Bit to write (0 or 1)
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*/
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void bio_putbit(int b)
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{
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if (bio_ct == 0) {
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bio_byteout();
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}
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bio_ct--;
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bio_buf |= b << bio_ct;
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}
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/*
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* Read bit.
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*
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*/
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int bio_getbit()
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{
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if (bio_ct == 0) {
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bio_bytein();
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}
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bio_ct--;
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return (bio_buf >> bio_ct) & 1;
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}
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/*
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* Write bits.
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*
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* v : Value of bits
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* n : Number of bits to write
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*/
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void bio_write(int v, int n)
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{
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int i;
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for (i = n - 1; i >= 0; i--) {
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bio_putbit((v >> i) & 1);
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}
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}
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/*
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* Read bits.
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*
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* n : Number of bits to read
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*/
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int bio_read(int n)
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{
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int i, v;
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v = 0;
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for (i = n - 1; i >= 0; i--) {
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v += bio_getbit() << i;
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}
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return v;
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}
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/*
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* Flush bits. Modified to eliminate longjmp !!
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*
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*/
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int bio_flush()
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{
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bio_ct = 0;
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if (bio_byteout())
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return 1;
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if (bio_ct == 7) {
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bio_ct = 0;
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if (bio_byteout())
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return 1;
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}
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return 0;
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}
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/*
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* Passes the ending bits (coming from flushing)
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*/
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int bio_inalign()
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{
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bio_ct = 0;
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if ((bio_buf & 0xff) == 0xff) {
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if (bio_bytein())
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return 1;
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bio_ct = 0;
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}
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return 0;
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}
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