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* Copyright 2007 Edgard Lima <edgard.lima@indt.org.br>
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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* Alternatively, the contents of this file may be used under the
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* GNU Lesser General Public License Version 2.1 (the "LGPL"), in
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* which case the following provisions apply instead of the ones
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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* @short_description: This module provides high-level functions to parse files
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* This module find out the stream type (JPEG or PNG), and provide functions to
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* the caller to know where are the metadata chunks and where should it be
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* written, as well, it gives the caller the metedata chunk to be written and
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* also gets a metadata chunk and wraps it according the strem type
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* #metadata_init must be called before any other function in this module and
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* must be paired with a call to #metadata_dispose. #metadata_parse is used to
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* parse the stream (find the metadata chunks and the place it should be
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* written to. And #metadata_lazy_update is used by muxers to wrap the metadata
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* chunk according the stream type specification. Actually after indentify the
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* stream type, the real jog of parsing is delivered to speciallized module.
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* See, #metadata[mux/parse][jpeg/png].[c/h] files.
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* Last reviewed on 2008-01-24 (0.10.15)
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* static helper functions declaration
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static MetadataParsingReturn
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metadata_parse_none (MetaData * meta_data, const guint8 * data,
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guint32 * data_size, guint8 ** next_start, guint32 * next_size);
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* extern functions implementations
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* @meta_data: [in] metadata handler to be inited
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* @options: [in] which types of metadata will be processed (EXIF, IPTC and/or
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* XMP) and how it will be handled (DEMUXING or MUXING). Look at #MetaOptions
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* to see the available options.
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* Init metadata handle.
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* This function must be called before any other function from this module.
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* This function must not be called twice without call to #metadata_dispose
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* @see_also: #metadata_dispose #metadata_parse
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metadata_init (MetaData ** meta_data, const MetaOptions options)
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if (meta_data == NULL)
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metadata_dispose (meta_data);
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(*meta_data) = g_new (MetaData, 1);
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(*meta_data)->state = STATE_NULL;
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(*meta_data)->img_type = IMG_NONE;
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(*meta_data)->options = options;
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(*meta_data)->offset_orig = 0;
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(*meta_data)->exif_adapter = NULL;
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(*meta_data)->iptc_adapter = NULL;
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(*meta_data)->xmp_adapter = NULL;
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if ((*meta_data)->options & META_OPT_DEMUX) {
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/* when parsing we will probably strip only 3 chunk (exif, iptc and xmp)
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so we use 4 just in case there is more than one chunk of them.
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But this is just for convinience, 'cause the chunk_array increases
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metadata_chunk_array_init (&(*meta_data)->strip_chunks, 4);
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/* at most 1 chunk will be injected (JPEG JFIF) */
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metadata_chunk_array_init (&(*meta_data)->inject_chunks, 1);
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/* at most 1 chunk will be striped (JPEG JFIF) */
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metadata_chunk_array_init (&(*meta_data)->strip_chunks, 1);
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/* at most 3 chunk will be injected (EXIF, IPTC, XMP) */
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metadata_chunk_array_init (&(*meta_data)->inject_chunks, 3);
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* @meta_data: [in] metadata handler to be freed
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* Call this function to free any resource allocated by #metadata_init
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* @see_also: #metadata_init
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metadata_dispose (MetaData ** meta_data)
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if (meta_data == NULL || (*meta_data) == NULL)
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switch ((*meta_data)->img_type) {
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if (G_LIKELY ((*meta_data)->options & META_OPT_DEMUX))
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metadataparse_jpeg_dispose (&(*meta_data)->format_data.jpeg_parse);
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metadatamux_jpeg_dispose (&(*meta_data)->format_data.jpeg_mux);
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if (G_LIKELY ((*meta_data)->options & META_OPT_DEMUX))
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metadataparse_png_dispose (&(*meta_data)->format_data.png_parse);
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metadatamux_png_dispose (&(*meta_data)->format_data.png_mux);
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metadata_chunk_array_free (&(*meta_data)->strip_chunks);
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metadata_chunk_array_free (&(*meta_data)->inject_chunks);
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if ((*meta_data)->xmp_adapter) {
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gst_object_unref ((*meta_data)->xmp_adapter);
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(*meta_data)->xmp_adapter = NULL;
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if ((*meta_data)->iptc_adapter) {
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gst_object_unref ((*meta_data)->iptc_adapter);
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(*meta_data)->iptc_adapter = NULL;
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if ((*meta_data)->exif_adapter) {
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gst_object_unref ((*meta_data)->exif_adapter);
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(*meta_data)->exif_adapter = NULL;
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* @meta_data: [in] metadata handle
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* @buf: [in] data to be parsed
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* @buf_size: [in] size of @buf in bytes
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* @next_offset: [out] number of bytes to jump from the begining of @buf in
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* the next call. i.e, 0 (zero) mean that in the next call this function @buf
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* must have the same data (probably resized, see @next_size)
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* @next_size: [out] number of minimal bytes in @buf for the next call to this
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* This function is used to parse the stream step-by-step incrementaly, which
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* means, discover the stream type and find the metadata chunks
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* (#META_OPT_DEMUX), or point out where metadata chunks should be written
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* (#META_OPT_MUX). It is important to notice that there could be both strip
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* and inject chunks in both demuxing and muxing modes.
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* @see_also: #metadata_init #META_DATA_STRIP_CHUNKS #META_DATA_INJECT_CHUNKS
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* <listitem><para>%META_PARSING_ERROR
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* <listitem><para>%META_PARSING_DONE if parse has finished. Now strip and
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* inject chunks has been found
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* <listitem><para>%META_PARSING_NEED_MORE_DATA if this function should be
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* called again (look @next_offset and @next_size)
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MetadataParsingReturn
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metadata_parse (MetaData * meta_data, const guint8 * buf,
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guint32 buf_size, guint32 * next_offset, guint32 * next_size)
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int ret = META_PARSING_DONE;
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guint8 *next_start = (guint8 *) buf;
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if (meta_data->state == STATE_NULL) {
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metadata_parse_none (meta_data, buf, &buf_size, &next_start, next_size);
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if (ret == META_PARSING_DONE)
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meta_data->state = STATE_READING;
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switch (meta_data->img_type) {
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if (G_LIKELY (meta_data->options & META_OPT_DEMUX))
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metadataparse_jpeg_parse (&meta_data->format_data.jpeg_parse,
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(guint8 *) buf, &buf_size, meta_data->offset_orig, &next_start,
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metadatamux_jpeg_parse (&meta_data->format_data.jpeg_mux,
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(guint8 *) buf, &buf_size, meta_data->offset_orig, &next_start,
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if (G_LIKELY (meta_data->options & META_OPT_DEMUX))
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metadataparse_png_parse (&meta_data->format_data.png_parse,
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(guint8 *) buf, &buf_size, meta_data->offset_orig, &next_start,
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metadatamux_png_parse (&meta_data->format_data.png_mux,
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(guint8 *) buf, &buf_size, meta_data->offset_orig, &next_start,
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ret = META_PARSING_ERROR;
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*next_offset = next_start - buf;
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meta_data->offset_orig += *next_offset;
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if (ret == META_PARSING_DONE) {
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meta_data->state = STATE_DONE;
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* metadata_lazy_update:
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* @meta_data: [in] metata handle
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* This function must be called after #metadata_parse and after the element
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* has modified the segments (chunks)
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* Data written to #META_DATA_INJECT_CHUNKS will be properly wrapped
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* This function is really importante in case o muxing 'cause:
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* 1- 'cause gives the oportunity to muxers to wrapper new segments with
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* ex: in case of JPEG it can wrap the EXIF chunk (created using tags) with
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* chunk id and chunk size
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* 2- 'cause gives the oportunity to muxer to decide if some chunks should
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* still be striped/injected
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* ex: if there is no EXIF chunk to be inserted, the muxer decides to not
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* @see_also: #metadata_parse #META_DATA_INJECT_CHUNKS
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metadata_lazy_update (MetaData * meta_data)
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switch (meta_data->img_type) {
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if (G_LIKELY (meta_data->options & META_OPT_DEMUX))
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metadataparse_jpeg_lazy_update (&meta_data->format_data.jpeg_parse);
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metadatamux_jpeg_lazy_update (&meta_data->format_data.jpeg_mux);
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if (G_LIKELY (meta_data->options & META_OPT_DEMUX))
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metadataparse_png_lazy_update (&meta_data->format_data.png_parse);
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metadatamux_png_lazy_update (&meta_data->format_data.png_mux);
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* static helper functions implementation
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* metadata_parse_none:
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* @meta_data: [in] metata handle
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* @buf: [in] data to be parsed
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* @buf_size: [in] size of @buf in bytes
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* @next_offset: [out] number of bytes to jump from the begining of @buf in
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* the next call. i.e, 0 (zero) mean that in the next call this function @buf
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* must have the same data (probably resized, see @next_size)
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* @next_size: [out] number of minimal bytes in @buf for the next call to this
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* Parse the fisrt bytes of the stream to identify the stream type
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* @see_also: metadata_parse
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* <listitem><para>%META_PARSING_ERROR none of the alloed strem types (JPEG,
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* PNG) has been identified
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* <listitem><para>%META_PARSING_DONE if the stream type has been identified
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* <listitem><para>%META_PARSING_NEED_MORE_DATA if this function should be
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* called again (look @next_offset and @next_size)
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static MetadataParsingReturn
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metadata_parse_none (MetaData * meta_data, const guint8 * buf,
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guint32 * buf_size, guint8 ** next_start, guint32 * next_size)
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int ret = META_PARSING_ERROR;
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GstAdapter **exif = NULL;
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GstAdapter **iptc = NULL;
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GstAdapter **xmp = NULL;
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*next_start = (guint8 *) buf;
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meta_data->img_type = IMG_NONE;
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* Be sure of add checking for more types in order from the
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* less to more bytes need to detect the stream type.
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/* we need at least 3 bytes to see if it is JPEG */
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ret = META_PARSING_NEED_MORE_DATA;
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if (meta_data->options & META_OPT_EXIF)
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exif = &meta_data->exif_adapter;
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if (meta_data->options & META_OPT_IPTC)
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iptc = &meta_data->iptc_adapter;
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if (meta_data->options & META_OPT_XMP)
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xmp = &meta_data->xmp_adapter;
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if (buf[0] == 0xFF && buf[1] == 0xD8 && buf[2] == 0xFF) {
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if (G_LIKELY (meta_data->options & META_OPT_DEMUX))
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metadataparse_jpeg_init (&meta_data->format_data.jpeg_parse, exif, iptc,
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xmp, &meta_data->strip_chunks, &meta_data->inject_chunks,
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meta_data->options & META_OPT_PARSE_ONLY);
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metadatamux_jpeg_init (&meta_data->format_data.jpeg_mux,
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&meta_data->strip_chunks, &meta_data->inject_chunks);
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ret = META_PARSING_DONE;
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meta_data->img_type = IMG_JPEG;
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/* we need at least 8 bytes to see if it is PNG */
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ret = META_PARSING_NEED_MORE_DATA;
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if (buf[0] == 0x89 && buf[1] == 0x50 && buf[2] == 0x4E && buf[3] == 0x47 &&
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buf[4] == 0x0D && buf[5] == 0x0A && buf[6] == 0x1A && buf[7] == 0x0A) {
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if (G_LIKELY (meta_data->options & META_OPT_DEMUX))
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metadataparse_png_init (&meta_data->format_data.png_parse, exif, iptc,
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xmp, &meta_data->strip_chunks, &meta_data->inject_chunks,
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meta_data->options & META_OPT_PARSE_ONLY);
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metadatamux_png_init (&meta_data->format_data.png_mux,
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&meta_data->strip_chunks, &meta_data->inject_chunks);
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ret = META_PARSING_DONE;
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meta_data->img_type = IMG_PNG;
added
removed
ext/metadata/metadata.c
