153 lines
3.2 KiB
C
153 lines
3.2 KiB
C
/*
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* Copyright (c) 2001-2002, David Janssens
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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 "cio.h"
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#include <setjmp.h>
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static unsigned char *cio_start; /* pointer to the start of the stream */
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static unsigned char *cio_end; /* pointer to the end of the stream */
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static unsigned char *cio_bp; /* pointer to the present position */
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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 cio_numbytes()
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{
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return cio_bp - cio_start;
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}
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/*
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* Get position in byte stream.
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*/
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int cio_tell()
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{
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return cio_bp - cio_start;
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}
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/*
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* Set position in byte stream.
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*
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* pos : position, in number of bytes, from the beginning of the stream
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*/
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void cio_seek(int pos)
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{
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cio_bp = cio_start + pos;
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}
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/*
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* Number of bytes left before the end of the stream.
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*/
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int cio_numbytesleft()
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{
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return cio_end - cio_bp;
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}
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/*
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* Get pointer to the current position in the stream.
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*/
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unsigned char *cio_getbp()
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{
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return cio_bp;
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}
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/*
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* Initialize byte IO
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*
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* bp : destination/source stream
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* len : length of the stream
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*/
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void cio_init(unsigned char *bp, int len)
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{
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cio_start = bp;
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cio_end = bp + len;
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cio_bp = bp;
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}
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/*
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* Write a byte.
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*/
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void cio_byteout(unsigned char v)
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{
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if (cio_bp >= cio_end)
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longjmp(j2k_error, 1);
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*cio_bp++ = v;
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}
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/*
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* Read a byte.
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*/
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unsigned char cio_bytein()
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{
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if (cio_bp >= cio_end)
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longjmp(j2k_error, 1);
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return *cio_bp++;
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}
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/*
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* Write some bytes.
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*
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* v : value to write
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* n : number of bytes to write
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*/
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void cio_write(unsigned 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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cio_byteout((unsigned char) ((v >> (i << 3)) & 0xff));
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}
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}
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/*
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* Read some bytes.
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*
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* n : number of bytes to read
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*
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* return : value of the n bytes read
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*/
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unsigned int cio_read(int n)
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{
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int i;
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unsigned int v;
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v = 0;
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for (i = n - 1; i >= 0; i--) {
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v += cio_bytein() << (i << 3);
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}
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return v;
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}
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/*
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* Skip some bytes.
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*
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* n : number of bytes to skip
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*/
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void cio_skip(int n)
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{
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cio_bp += n;
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}
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