lib/openmj2/cio.c

/*
 * The copyright in this software is being made available under the 2-clauses
 * BSD License, included below. This software may be subject to other third
 * party and contributor rights, including patent rights, and no such rights
 * are granted under this license.
 *
 * Copyright (c) 2002-2014, Universite catholique de Louvain (UCL), Belgium
 * Copyright (c) 2002-2014, Professor Benoit Macq
 * Copyright (c) 2001-2003, David Janssens
 * Copyright (c) 2002-2003, Yannick Verschueren
 * Copyright (c) 2003-2007, Francois-Olivier Devaux
 * Copyright (c) 2003-2014, Antonin Descampe
 * Copyright (c) 2005, Herve Drolon, FreeImage Team
 * 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"

/* ----------------------------------------------------------------------- */

opj_cio_t* OPJ_CALLCONV opj_cio_open(opj_common_ptr cinfo,
                                     unsigned char *buffer, int length)
{
    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 */
        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");
            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;
}

void OPJ_CALLCONV opj_cio_close(opj_cio_t *cio)
{
    if (cio) {
        if (cio->openmode == OPJ_STREAM_WRITE) {
            /* destroy the allocated buffer */
            opj_free(cio->buffer);
        }
        /* destroy the cio */
        opj_free(cio);
    }
}


/* ----------------------------------------------------------------------- */

/*
 * Get position in byte stream.
 */
int OPJ_CALLCONV cio_tell(opj_cio_t *cio)
{
    return cio->bp - cio->start;
}

/*
 * 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)
{
    cio->bp = cio->start + pos;
}

/*
 * Number of bytes left before the end of the stream.
 */
int cio_numbytesleft(opj_cio_t *cio)
{
    return cio->end - cio->bp;
}

/*
 * Get pointer to the current position in the stream.
 */
unsigned char *cio_getbp(opj_cio_t *cio)
{
    return cio->bp;
}

/*
 * Write a byte.
 */
opj_bool cio_byteout(opj_cio_t *cio, unsigned char v)
{
    if (cio->bp >= cio->end) {
        opj_event_msg(cio->cinfo, EVT_ERROR, "write error\n");
        return OPJ_FALSE;
    }
    *cio->bp++ = v;
    return OPJ_TRUE;
}

/*
 * Read a byte.
 */
unsigned char cio_bytein(opj_cio_t *cio)
{
    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);
        return 0;
    }
    return *cio->bp++;
}

/*
 * Write some bytes.
 *
 * v : value to write
 * n : number of bytes to write
 */
unsigned int OPJ_CALLCONV cio_write(opj_cio_t *cio, unsigned int64 v, int n)
{
    int i;
    for (i = n - 1; i >= 0; i--) {
        if (!cio_byteout(cio, (unsigned char)((v >> (i << 3)) & 0xff))) {
            return 0;
        }
    }
    return n;
}

/*
 * Read some bytes.
 *
 * n : number of bytes to read
 *
 * return : value of the n bytes read
 */
unsigned int OPJ_CALLCONV cio_read(opj_cio_t *cio, int n)
{
    int i;
    unsigned int v;
    v = 0;
    for (i = n - 1; i >= 0; i--) {
        v += cio_bytein(cio) << (i << 3);
    }
    return v;
}

/*
 * Skip some bytes.
 *
 * n : number of bytes to skip
 */
void OPJ_CALLCONV cio_skip(opj_cio_t *cio, int n)
{
    cio->bp += n;
}