openjpeg/libopenjpeg/cio.c

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/*
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* Copyright (c) 2002-2007, Communications and Remote Sensing Laboratory, Universite catholique de Louvain (UCL), Belgium
* Copyright (c) 2002-2007, Professor Benoit Macq
* Copyright (c) 2001-2003, David Janssens
* Copyright (c) 2002-2003, Yannick Verschueren
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* Copyright (c) 2003-2007, Francois-Olivier Devaux and Antonin Descampe
* Copyright (c) 2005, Herve Drolon, FreeImage Team
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* 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 "opj_includes.h"
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/* ----------------------------------------------------------------------- */
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opj_cio_t* OPJ_CALLCONV opj_cio_open(opj_common_ptr cinfo, unsigned char *buffer, int length) {
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opj_cp_t *cp = NULL;
opj_cio_t *cio = (opj_cio_t*)opj_malloc(sizeof(opj_cio_t));
if(!cio) return NULL;
cio->cinfo = cinfo;
if(buffer && length) {
/* wrap a user buffer containing the encoded image */
cio->openmode = OPJ_STREAM_READ;
cio->buffer = buffer;
cio->length = length;
}
else if(!buffer && !length && cinfo) {
/* allocate a buffer for the encoded image */
cio->openmode = OPJ_STREAM_WRITE;
switch(cinfo->codec_format) {
case CODEC_J2K:
cp = ((opj_j2k_t*)cinfo->j2k_handle)->cp;
break;
case CODEC_JP2:
cp = ((opj_jp2_t*)cinfo->jp2_handle)->j2k->cp;
break;
default:
opj_free(cio);
return NULL;
}
cio->length = (unsigned int) (0.1625 * cp->img_size + 2000); /* 0.1625 = 1.3/8 and 2000 bytes as a minimum for headers */
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cio->buffer = (unsigned char *)opj_malloc(cio->length);
if(!cio->buffer) {
opj_event_msg(cio->cinfo, EVT_ERROR, "Error allocating memory for compressed bitstream\n");
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opj_free(cio);
return NULL;
}
}
else {
opj_free(cio);
return NULL;
}
/* Initialize byte IO */
cio->start = cio->buffer;
cio->end = cio->buffer + cio->length;
cio->bp = cio->buffer;
return cio;
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}
void OPJ_CALLCONV opj_cio_close(opj_cio_t *cio) {
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if(cio) {
if(cio->openmode == OPJ_STREAM_WRITE) {
/* destroy the allocated buffer */
opj_free(cio->buffer);
}
/* destroy the cio */
opj_free(cio);
}
}
/* ----------------------------------------------------------------------- */
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/*
* Get position in byte stream.
*/
int OPJ_CALLCONV cio_tell(opj_cio_t *cio) {
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return cio->bp - cio->start;
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}
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/*
* Set position in byte stream.
*
* pos : position, in number of bytes, from the beginning of the stream
*/
void OPJ_CALLCONV cio_seek(opj_cio_t *cio, int pos) {
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cio->bp = cio->start + pos;
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}
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/*
* Number of bytes left before the end of the stream.
*/
int cio_numbytesleft(opj_cio_t *cio) {
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return cio->end - cio->bp;
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}
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/*
* Get pointer to the current position in the stream.
*/
unsigned char *cio_getbp(opj_cio_t *cio) {
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return cio->bp;
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}
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/*
* Write a byte.
*/
opj_bool cio_byteout(opj_cio_t *cio, unsigned char v) {
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if (cio->bp >= cio->end) {
opj_event_msg(cio->cinfo, EVT_ERROR, "write error\n");
return OPJ_FALSE;
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}
*cio->bp++ = v;
return OPJ_TRUE;
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}
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/*
* Read a byte.
*/
unsigned char cio_bytein(opj_cio_t *cio) {
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if (cio->bp >= cio->end) {
opj_event_msg(cio->cinfo, EVT_ERROR, "read error: passed the end of the codestream (start = %d, current = %d, end = %d\n", cio->start, cio->bp, cio->end);
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return 0;
}
return *cio->bp++;
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}
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/*
* Write some bytes.
*
* v : value to write
* n : number of bytes to write
*/
unsigned int cio_write(opj_cio_t *cio, unsigned int64 v, int n) {
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int i;
for (i = n - 1; i >= 0; i--) {
if( !cio_byteout(cio, (unsigned char) ((v >> (i << 3)) & 0xff)) )
return 0;
}
return n;
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}
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/*
* Read some bytes.
*
* n : number of bytes to read
*
* return : value of the n bytes read
*/
unsigned int cio_read(opj_cio_t *cio, int n) {
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int i;
unsigned int v;
v = 0;
for (i = n - 1; i >= 0; i--) {
v += cio_bytein(cio) << (i << 3);
}
return v;
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}
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/*
* Skip some bytes.
*
* n : number of bytes to skip
*/
void cio_skip(opj_cio_t *cio, int n) {
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cio->bp += n;
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}