/*

 * jpegdest.c

 *

 * Copyright (C) 2014-2022 Timo Kokkonen

 * All Rights Reserved.

 *

 * custom libjpeg "Destination Manager" for saving into RAM

 *

 * SPDX-License-Identifier: GPL-3.0-or-later

 *

 * This file is part of JPEGoptim.

 *

 * JPEGoptim is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * JPEGoptim is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with JPEGoptim. If not, see <https://www.gnu.org/licenses/>.

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <jpeglib.h>

#include <jerror.h>

#include "jpegoptim.h"

/* custom jpeg destination manager object */

typedef struct {

  struct jpeg_destination_mgr pub; /* public fields */

  unsigned char **buf_ptr;

  size_t *bufsize_ptr;

  size_t incsize;

  unsigned char *buf;

  size_t bufsize;

} jpeg_memory_destination_mgr;

typedef jpeg_memory_destination_mgr* jpeg_memory_destination_ptr;

static void jpeg_memory_init_destination (j_compress_ptr cinfo)

{

  jpeg_memory_destination_ptr dest = (jpeg_memory_destination_ptr) cinfo->dest;

  dest->pub.next_output_byte = dest->buf;

  dest->pub.free_in_buffer = dest->bufsize;

}

static boolean jpeg_memory_empty_output_buffer (j_compress_ptr cinfo)

{

  jpeg_memory_destination_ptr dest = (jpeg_memory_destination_ptr) cinfo->dest;

  unsigned char *newbuf;

  /* abort if incsize is 0 (no expansion of buffer allowed) */

  if (dest->incsize == 0) ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 42);

  /* otherwise, try expanding buffer... */

  newbuf = realloc(dest->buf,dest->bufsize + dest->incsize);

  if (!newbuf) ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 42);

  dest->pub.next_output_byte = newbuf + dest->bufsize;

  dest->pub.free_in_buffer = dest->incsize;

  *dest->buf_ptr = newbuf;

  dest->buf = newbuf;

  dest->bufsize += dest->incsize;

  dest->incsize *= 2;

  return TRUE;

}

static void jpeg_memory_term_destination (j_compress_ptr cinfo)

{

  jpeg_memory_destination_ptr dest = (jpeg_memory_destination_ptr) cinfo->dest;

  *dest->buf_ptr = dest->buf;

  *dest->bufsize_ptr = dest->bufsize - dest->pub.free_in_buffer;

}

void jpeg_memory_dest (j_compress_ptr cinfo, unsigned char **bufptr, size_t *bufsizeptr, size_t incsize)

{

  jpeg_memory_destination_ptr dest;

  if (!cinfo || !bufptr || !bufsizeptr)

    fatal("invalid call to jpeg_memory_dest()");

  if (!*bufptr || *bufsizeptr == 0)

    fatal("invalid buffer passed to jpeg_memory_dest()");

  /* Allocate destination manager object for compress object, if needed. */

  if (!cinfo->dest) {

    cinfo->dest = (struct jpeg_destination_mgr *)

      (*cinfo->mem->alloc_small) ( (j_common_ptr) cinfo,

            JPOOL_PERMANENT,

            sizeof(jpeg_memory_destination_mgr) );

  }

  dest = (jpeg_memory_destination_ptr)cinfo->dest;

  dest->buf_ptr = bufptr;

  dest->buf = *bufptr;

  dest->bufsize_ptr = bufsizeptr;

  dest->bufsize = *bufsizeptr;

  dest->incsize = incsize;

  dest->pub.init_destination = jpeg_memory_init_destination;

  dest->pub.empty_output_buffer = jpeg_memory_empty_output_buffer;

  dest->pub.term_destination = jpeg_memory_term_destination;

}

/* eof :-) */