openjpeg/libopenjpeg/cio.c

/*
 * Copyright (c) 2001-2003, David Janssens
 * Copyright (c) 2002-2003, Yannick Verschueren
 * Copyright (c) 2003-2005, Francois Devaux and Antonin Descampe
 * Copyright (c) 2005, Herv<EFBFBD> Drolon, FreeImage Team
 * Copyright (c) 2002-2005, 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 "opj_includes.h"

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

opj_cio_t* 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 = cp->tdx * cp->tdy * cp->tw * cp->th * 2;
    cio->buffer = (unsigned char *)opj_malloc(cio->length);
    if(!cio->buffer) {
      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_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 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 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.
 */
bool cio_byteout(opj_cio_t *cio, unsigned char v) {
  if (cio->bp >= cio->end) {
    opg_event_msg(cio->cinfo, EVT_ERROR, "write error\n");
    return false;
  }
  *cio->bp++ = v;
  return true;
}

/*
 * Read a byte.
 */
unsigned char cio_bytein(opj_cio_t *cio) {
  if (cio->bp >= cio->end) {
    opg_event_msg(cio->cinfo, EVT_ERROR, "read error\n");
    return 0;
  }
  return *cio->bp++;
}

/*
 * Write some bytes.
 *
 * v : value to write
 * n : number of bytes to write
 */
unsigned int cio_write(opj_cio_t *cio, unsigned int 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 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 cio_skip(opj_cio_t *cio, int n) {
  cio->bp += n;
}