/* ============================================================
 *
 * This file is a part of digiKam project
 * https://www.digikam.org
 *
 * Date        : 1998-01-25
 * Description : helper methods to handle ICC color profile with JPEG file.
 *
 * SPDX-FileCopyrightText: 1998-2004 by Marti Maria <info at littlecms dot com>
 * SPDX-FileCopyrightText: 2005-2024 by Gilles Caulier <caulier dot gilles at gmail dot com>
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * ============================================================ */

/**
 * Notes from Little CMS project (www.littlecms.com)
 *
 * This file provides code to read and write International Color Consortium
 * (ICC) device profiles embedded in JFIF JPEG image files.  The ICC has
 * defined a standard format for including such data in JPEG "APP2" markers.
 * The code given here does not know anything about the internal structure
 * of the ICC profile data; it just knows how to put the profile data into
 * a JPEG file being written, or get it back out when reading.
 *
 * This code depends on new features added to the IJG JPEG library as of
 * IJG release 6b; it will not compile or work with older IJG versions.
 *
 * This code would need surgery to work on 16-bit-int machines
 * with ICC profiles exceeding 64K bytes in size. See iccjpeg.c
 * for details.
 */

#pragma once

#include <stdio.h>    /* needed to define "FILE", "NULL" */
#include <jpeglib.h>

#include "digikam_export.h"

/**
 * This routine writes the given ICC profile data into a JPEG file.
 * It *must* be called AFTER calling jpeg_start_compress() and BEFORE
 * the first call to jpeg_write_scanlines().
 * (This ordering ensures that the APP2 marker(s) will appear after the
 * SOI and JFIF or Adobe markers, but before all else.)
 */
DIGIKAM_EXPORT extern void write_icc_profile JPP((j_compress_ptr cinfo,
                                                 const JOCTET* icc_data_ptr,
                                                 unsigned int icc_data_len));

/**
 * Reading a JPEG file that may contain an ICC profile requires two steps:
 *
 * 1. After jpeg_create_decompress() but before jpeg_read_header(),
 *    call setup_read_icc_profile().  This routine tells the IJG library
 *    to save in memory any APP2 markers it may find in the file.
 *
 * 2. After jpeg_read_header(), call read_icc_profile() to find out
 *    whether there was a profile and obtain it if so.
 */

/**
 * Prepare for reading an ICC profile
 */
DIGIKAM_EXPORT extern void setup_read_icc_profile JPP((j_decompress_ptr cinfo));

/**
 * See if there was an ICC profile in the JPEG file being read;
 * if so, reassemble and return the profile data.
 *
 * TRUE is returned if an ICC profile was found, FALSE if not.
 * If TRUE is returned, *icc_data_ptr is set to point to the
 * returned data, and *icc_data_len is set to its length.
 *
 * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
 * and must be freed by the caller with free() when the caller no longer
 * needs it.  (Alternatively, we could write this routine to use the
 * IJG library's memory allocator, so that the data would be freed implicitly
 * at jpeg_finish_decompress() time.  But it seems likely that many apps
 * will prefer to have the data stick around after decompression finishes.)
 */
DIGIKAM_EXPORT extern boolean read_icc_profile JPP((j_decompress_ptr cinfo,
                                                   JOCTET** icc_data_ptr,
                                                   unsigned int* icc_data_len));
