mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-07-11 17:06:45 +00:00
5540ec23ec
Sprinkle more debug log statements into the code. Move some repeaded string constant into header files and use sizeof instead of manually counted bytes. Add comments.
553 lines
17 KiB
C
553 lines
17 KiB
C
/*
|
|
* GStreamer
|
|
* Copyright 2007 Edgard Lima <edgard.lima@indt.org.br>
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a
|
|
* copy of this software and associated documentation files (the "Software"),
|
|
* to deal in the Software without restriction, including without limitation
|
|
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
|
|
* and/or sell copies of the Software, and to permit persons to whom the
|
|
* Software is furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
|
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
|
* DEALINGS IN THE SOFTWARE.
|
|
*
|
|
* Alternatively, the contents of this file may be used under the
|
|
* GNU Lesser General Public License Version 2.1 (the "LGPL"), in
|
|
* which case the following provisions apply instead of the ones
|
|
* mentioned above:
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Library General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This library 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
|
|
* Library General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Library General Public
|
|
* License along with this library; if not, write to the
|
|
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
* Boston, MA 02111-1307, USA.
|
|
*/
|
|
|
|
/*
|
|
* SECTION: metadatamuxpng
|
|
* @short_description: This module provides functions to parse PNG files in
|
|
* order to write metadata to it.
|
|
*
|
|
* This module parses a PNG stream to find the places in which XMP metadata
|
|
* chunks would be written. It also wraps metadata chunks with PNG marks
|
|
* according to the specification.
|
|
*
|
|
* <refsect2>
|
|
* <para>
|
|
* #metadatamux_png_init must be called before any other function in this
|
|
* module and must be paired with a call to #metadatamux_png_dispose.
|
|
* #metadatamux_png_parse is used to parse the stream (find the place
|
|
* metadata chunks should be written to).
|
|
* #metadatamux_png_lazy_update do nothing.
|
|
* </para>
|
|
* <para>
|
|
* EXIF chunks will always be the first chunk (replaces JFIF). IPTC and XMP
|
|
* chunks will be placed or second chunk (after JFIF or EXIF) or third chunk
|
|
* if both (IPTC and XMP) are written to the file.
|
|
* </para>
|
|
* <para>
|
|
* When a EXIF chunk is written to the PNG stream, if there is a JFIF chunk
|
|
* as the first chunk, it will be stripped out.
|
|
* </para>
|
|
* </refsect2>
|
|
*
|
|
* Last reviewed on 2008-01-24 (0.10.15)
|
|
*/
|
|
|
|
/*
|
|
* includes
|
|
*/
|
|
|
|
#include "metadatamuxpng.h"
|
|
|
|
#include <string.h>
|
|
|
|
/*
|
|
* defines and macros
|
|
*/
|
|
|
|
#define READ(buf, size) ( (size)--, *((buf)++) )
|
|
|
|
/*
|
|
* static global vars
|
|
*/
|
|
|
|
static const guint32 metadatamux_crc_table[256] = {
|
|
0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
|
|
0xe963a535,
|
|
0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b,
|
|
0x7eb17cbd,
|
|
0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
|
|
0x1adad47d,
|
|
0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, 0x646ba8c0, 0xfd62f97a,
|
|
0x8a65c9ec,
|
|
0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e,
|
|
0xd56041e4,
|
|
0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa,
|
|
0x42b2986c,
|
|
0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
|
|
0x26d930ac,
|
|
0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599,
|
|
0xb8bda50f,
|
|
0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11,
|
|
0xc1611dab,
|
|
0xb6662d3d, 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589,
|
|
0x06b6b51f,
|
|
0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
|
|
0x7f6a0dbb,
|
|
0x086d3d2d, 0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8,
|
|
0xf262004e,
|
|
0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
|
|
0x8bbeb8ea,
|
|
0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, 0x4db26158,
|
|
0x3ab551ce,
|
|
0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
|
|
0x4369e96a,
|
|
0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f,
|
|
0xdd0d7cc9,
|
|
0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3,
|
|
0xb966d409,
|
|
0xce61e49f, 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17,
|
|
0x2eb40d81,
|
|
0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
|
|
0xead54739,
|
|
0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e,
|
|
0x7a6a5aa8,
|
|
0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, 0x8708a3d2,
|
|
0x1e01f268,
|
|
0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, 0xfed41b76,
|
|
0x89d32be0,
|
|
0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
|
|
0xd6d6a3e8,
|
|
0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd,
|
|
0x48b2364b,
|
|
0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
|
|
0x316e8eef,
|
|
0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795,
|
|
0xbb0b4703,
|
|
0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
|
|
0xc2d7ffa7,
|
|
0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,
|
|
0x026d930a,
|
|
0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14,
|
|
0x7bb12bae,
|
|
0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4,
|
|
0xf1d4e242,
|
|
0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
|
|
0x88085ae6,
|
|
0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3,
|
|
0x166ccf45,
|
|
0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7,
|
|
0x4969474d,
|
|
0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53,
|
|
0xdebb9ec5,
|
|
0x47b2cf7f, 0x30b5ffe9, 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
|
|
0xbad03605,
|
|
0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02,
|
|
0x2a6f2b94,
|
|
0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
|
|
};
|
|
|
|
|
|
/*
|
|
* static helper functions declaration
|
|
*/
|
|
|
|
static MetadataParsingReturn
|
|
metadatamux_png_reading (PngMuxData * png_data, guint8 ** buf,
|
|
guint32 * bufsize, const guint32 offset, const guint8 * step_buf,
|
|
guint8 ** next_start, guint32 * next_size);
|
|
|
|
static guint32 metadatamux_update_crc (guint32 crc, guint8 * buf, guint32 len);
|
|
|
|
static guint32 metadatamux_calc_crc (guint8 * buf, guint32 len);
|
|
|
|
static void metadatamux_wrap_xmp_chunk (MetadataChunk * chunk);
|
|
|
|
/*
|
|
* extern functions implementations
|
|
*/
|
|
|
|
/*
|
|
* metadatamux_png_init:
|
|
* @png_data: [in] png data handler to be inited
|
|
* @strip_chunks: Array of chunks (offset and size) marked for removal
|
|
* @inject_chunks: Array of chunks (offset, data, size) marked for injection
|
|
* adapter (@exif_adpt, @iptc_adpt, @xmp_adpt). Or FALSE if should also put
|
|
* them on @strip_chunks.
|
|
*
|
|
* Init png data handle.
|
|
* This function must be called before any other function from this module.
|
|
* This function must not be called twice without call to
|
|
* #metadatamux_png_dispose beteween them.
|
|
* @see_also: #metadatamux_png_dispose #metadatamux_png_parse
|
|
*
|
|
* Returns: nothing
|
|
*/
|
|
|
|
void
|
|
metadatamux_png_init (PngMuxData * png_data,
|
|
MetadataChunkArray * strip_chunks, MetadataChunkArray * inject_chunks)
|
|
{
|
|
png_data->state = PNG_MUX_NULL;
|
|
|
|
png_data->strip_chunks = strip_chunks;
|
|
png_data->inject_chunks = inject_chunks;
|
|
}
|
|
|
|
/*
|
|
* metadatamux_png_dispose:
|
|
* png_data: [in] png data handler to be freed
|
|
*
|
|
* Call this function to free any resource allocated by #metadatamux_png_init
|
|
* @see_also: #metadatamux_png_init
|
|
*
|
|
* Returns: nothing
|
|
*/
|
|
|
|
void
|
|
metadatamux_png_dispose (PngMuxData * png_data)
|
|
{
|
|
png_data->strip_chunks = NULL;
|
|
png_data->inject_chunks = NULL;
|
|
|
|
png_data->state = PNG_MUX_NULL;
|
|
}
|
|
|
|
/*
|
|
* metadatamux_png_parse:
|
|
* @png_data: [in] png data handle
|
|
* @buf: [in] data to be parsed
|
|
* @bufsize: [in] size of @buf in bytes
|
|
* @offset: is the offset where @buf starts from the beginnig of the whole
|
|
* stream
|
|
* @next_start: is a pointer after @buf which indicates where @buf should start
|
|
* on the next call to this function. It means, that after returning, this
|
|
* function has consumed *@next_start - @buf bytes. Which also means
|
|
* that @offset should also be incremanted by (*@next_start - @buf) for the
|
|
* next time.
|
|
* @next_size: [out] number of minimal bytes in @buf for the next call to this
|
|
* function
|
|
*
|
|
* This function is used to parse a PNG stream step-by-step incrementally.
|
|
* Basically this function works like a state machine, that will run in a loop
|
|
* while there is still bytes in @buf to be read or it has finished parsing.
|
|
* If the it hasn't parsed yet and there is no more data in @buf, then the
|
|
* current state is saved and a indication will be make about the buffer to
|
|
* be passed by the caller function.
|
|
* @see_also: #metadatamux_png_init
|
|
*
|
|
* Returns:
|
|
* <itemizedlist>
|
|
* <listitem><para>%META_PARSING_ERROR
|
|
* </para></listitem>
|
|
* <listitem><para>%META_PARSING_DONE if parse has finished. Now strip and
|
|
* inject chunks has been found
|
|
* </para></listitem>
|
|
* <listitem><para>%META_PARSING_NEED_MORE_DATA if this function should be
|
|
* called again (look @next_start and @next_size)
|
|
* </para></listitem>
|
|
* </itemizedlist>
|
|
*/
|
|
|
|
MetadataParsingReturn
|
|
metadatamux_png_parse (PngMuxData * png_data, guint8 * buf,
|
|
guint32 * bufsize, const guint32 offset, guint8 ** next_start,
|
|
guint32 * next_size)
|
|
{
|
|
|
|
int ret = META_PARSING_DONE;
|
|
guint8 mark[8];
|
|
const guint8 *step_buf = buf;
|
|
|
|
*next_start = buf;
|
|
|
|
if (png_data->state == PNG_MUX_NULL) {
|
|
|
|
if (*bufsize < 8) {
|
|
*next_size = (buf - *next_start) + 8;
|
|
ret = META_PARSING_NEED_MORE_DATA;
|
|
goto done;
|
|
}
|
|
|
|
mark[0] = READ (buf, *bufsize);
|
|
mark[1] = READ (buf, *bufsize);
|
|
mark[2] = READ (buf, *bufsize);
|
|
mark[3] = READ (buf, *bufsize);
|
|
mark[4] = READ (buf, *bufsize);
|
|
mark[5] = READ (buf, *bufsize);
|
|
mark[6] = READ (buf, *bufsize);
|
|
mark[7] = READ (buf, *bufsize);
|
|
|
|
if (mark[0] != 0x89 || mark[1] != 0x50 || mark[2] != 0x4E || mark[3] != 0x47
|
|
|| mark[4] != 0x0D || mark[5] != 0x0A || mark[6] != 0x1A
|
|
|| mark[7] != 0x0A) {
|
|
ret = META_PARSING_ERROR;
|
|
goto done;
|
|
}
|
|
|
|
png_data->state = PNG_MUX_READING;
|
|
|
|
}
|
|
|
|
while (ret == META_PARSING_DONE) {
|
|
switch (png_data->state) {
|
|
case PNG_MUX_READING:
|
|
ret =
|
|
metadatamux_png_reading (png_data, &buf, bufsize,
|
|
offset, step_buf, next_start, next_size);
|
|
break;
|
|
case PNG_MUX_DONE:
|
|
goto done;
|
|
break;
|
|
default:
|
|
ret = META_PARSING_ERROR;
|
|
break;
|
|
}
|
|
}
|
|
|
|
done:
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
/*
|
|
* metadatamux_png_lazy_update:
|
|
* @png_data: [in] png data handle
|
|
*
|
|
* This function wrap metadata chunk with proper PNG bytes.
|
|
* @see_also: #metadata_lazy_update
|
|
*
|
|
* Returns: nothing
|
|
*/
|
|
|
|
void
|
|
metadatamux_png_lazy_update (PngMuxData * png_data)
|
|
{
|
|
gsize i;
|
|
MetadataChunkArray *chunks = png_data->inject_chunks;
|
|
|
|
GST_INFO ("checking %d chunks", chunks->len);
|
|
|
|
for (i = 0; i < chunks->len; ++i) {
|
|
|
|
GST_INFO ("checking chunk[%" G_GSIZE_FORMAT "], type=%d, len=%u",
|
|
i, chunks->chunk[i].type, chunks->chunk[i].size);
|
|
|
|
if (chunks->chunk[i].size > 0 && chunks->chunk[i].data) {
|
|
switch (chunks->chunk[i].type) {
|
|
case MD_CHUNK_XMP:
|
|
metadatamux_wrap_xmp_chunk (&chunks->chunk[i]);
|
|
break;
|
|
default:
|
|
GST_ERROR ("Unexpected chunk for PNG muxer.");
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* static helper functions implementation
|
|
*/
|
|
|
|
/*
|
|
* metadatamux_png_reading:
|
|
* @png_data: [in] png data handle
|
|
* @buf: [in] data to be parsed. @buf will increment during the parsing step.
|
|
* So it will hold the next byte to be read inside a parsing function or on
|
|
* the next nested parsing function. And so, @bufsize will decrement.
|
|
* @bufsize: [in] size of @buf in bytes. This value will decrement during the
|
|
* parsing for the same reason that @buf will advance.
|
|
* @offset: is the offset where @step_buf starts from the beginnig of the
|
|
* stream
|
|
* @step_buf: holds the pointer to the buffer passed to
|
|
* #metadatamux_png_parse. It means that any point inside this function
|
|
* the offset (related to the beginning of the whole stream) after the last
|
|
* byte read so far is "(*buf - step_buf) + offset"
|
|
* @next_start: is a pointer after @step_buf which indicates where the next
|
|
* call to #metadatamux_png_parse should start on the next call to this
|
|
* function. It means, that after return, this function has
|
|
* consumed *@next_start - @buf bytes. Which also means that @offset should
|
|
* also be incremanted by (*@next_start - @buf) for the next time.
|
|
* @next_size: [out] number of minimal bytes in @buf for the next call to this
|
|
* function
|
|
*
|
|
* This function is used to parse a PNG stream step-by-step incrementally.
|
|
* If this function quickly finds the place (offset) in which EXIF, IPTC and
|
|
* XMP chunk should be written to.
|
|
* The found places are written to @png_data->inject_chunks
|
|
* @see_also: #metadatamux_png_init
|
|
*
|
|
* Returns:
|
|
* <itemizedlist>
|
|
* <listitem><para>%META_PARSING_ERROR
|
|
* </para></listitem>
|
|
* <listitem><para>%META_PARSING_DONE if parse has finished. Now strip and
|
|
* inject chunks has been found. Or some chunk has been found and should be
|
|
* held or jumped.
|
|
* </para></listitem>
|
|
* <listitem><para>%META_PARSING_NEED_MORE_DATA if this function should be
|
|
* called again (look @next_start and @next_size)
|
|
* </para></listitem>
|
|
* </itemizedlist>
|
|
*/
|
|
|
|
|
|
static MetadataParsingReturn
|
|
metadatamux_png_reading (PngMuxData * png_data, guint8 ** buf,
|
|
guint32 * bufsize, const guint32 offset, const guint8 * step_buf,
|
|
guint8 ** next_start, guint32 * next_size)
|
|
{
|
|
|
|
int ret = META_PARSING_ERROR;
|
|
guint8 mark[4];
|
|
guint32 chunk_size = 0;
|
|
MetadataChunk chunk;
|
|
|
|
*next_start = *buf;
|
|
|
|
if (*bufsize < 8) {
|
|
*next_size = (*buf - *next_start) + 8;
|
|
ret = META_PARSING_NEED_MORE_DATA;
|
|
goto done;
|
|
}
|
|
|
|
chunk_size = READ (*buf, *bufsize) << 24;
|
|
chunk_size += READ (*buf, *bufsize) << 16;
|
|
chunk_size += READ (*buf, *bufsize) << 8;
|
|
chunk_size += READ (*buf, *bufsize);
|
|
|
|
mark[0] = READ (*buf, *bufsize);
|
|
mark[1] = READ (*buf, *bufsize);
|
|
mark[2] = READ (*buf, *bufsize);
|
|
mark[3] = READ (*buf, *bufsize);
|
|
|
|
if (!(mark[0] == 'I' && mark[1] == 'H' && mark[2] == 'D' && mark[3] == 'R')) {
|
|
ret = META_PARSING_ERROR;
|
|
png_data->state = PNG_MUX_NULL;
|
|
goto done;
|
|
}
|
|
|
|
/* always inject after first chunk (IHDR) */
|
|
|
|
memset (&chunk, 0x00, sizeof (MetadataChunk));
|
|
/* 8(header) + 4(size) +4(id) + chunksize + 4(crc) */
|
|
chunk.offset_orig = chunk_size + 20;
|
|
chunk.type = MD_CHUNK_XMP;
|
|
|
|
metadata_chunk_array_append_sorted (png_data->inject_chunks, &chunk);
|
|
|
|
png_data->state = PNG_MUX_DONE;
|
|
ret = META_PARSING_DONE;
|
|
|
|
done:
|
|
|
|
return ret;
|
|
|
|
|
|
}
|
|
|
|
/*
|
|
* metadatamux_update_crc:
|
|
* @crc: seed to calculate the CRC
|
|
* @buf: data to calculate the CRC for
|
|
* @len: size in bytes of @buf
|
|
*
|
|
* Calculates the CRC of a data buffer for a seed @crc.
|
|
* @see_also: #metadatamux_calc_crc
|
|
*
|
|
* Returns: the CRC of the bytes buf[0..len-1].
|
|
*/
|
|
|
|
static guint32
|
|
metadatamux_update_crc (guint32 crc, guint8 * buf, guint32 len)
|
|
{
|
|
guint32 c = crc;
|
|
guint32 n;
|
|
|
|
for (n = 0; n < len; n++) {
|
|
c = metadatamux_crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
|
|
}
|
|
return c;
|
|
}
|
|
|
|
/*
|
|
* metadatamux_calc_crc:
|
|
* @buf: data to calculate the CRC for
|
|
* @len: size in bytes of @buf
|
|
*
|
|
* Calculates the CRC of a data buffer.
|
|
*
|
|
* Returns: the CRC of the bytes buf[0..len-1].
|
|
*/
|
|
|
|
static guint32
|
|
metadatamux_calc_crc (guint8 * buf, guint32 len)
|
|
{
|
|
return metadatamux_update_crc (0xffffffffL, buf, len) ^ 0xffffffffL;
|
|
}
|
|
|
|
|
|
/*
|
|
* metadatamux_wrap_xmp_chunk:
|
|
* @chunk: chunk to be wrapped
|
|
*
|
|
* Wraps a XMP chunk with proper PNG bytes (mark, size and crc in the end)
|
|
*
|
|
* Returns: nothing
|
|
*/
|
|
|
|
static void
|
|
metadatamux_wrap_xmp_chunk (MetadataChunk * chunk)
|
|
{
|
|
static const char XmpHeader[] = "XML:com.adobe.xmp";
|
|
guint8 *data = NULL;
|
|
guint32 crc;
|
|
|
|
data = g_new (guint8, 12 + 18 + 4 + chunk->size);
|
|
|
|
memcpy (data + 8, XmpHeader, 18);
|
|
memset (data + 8 + 18, 0x00, 4);
|
|
memcpy (data + 8 + 18 + 4, chunk->data, chunk->size);
|
|
g_free (chunk->data);
|
|
chunk->data = data;
|
|
chunk->size += 18 + 4;
|
|
data[0] = (chunk->size >> 24) & 0xFF;
|
|
data[1] = (chunk->size >> 16) & 0xFF;
|
|
data[2] = (chunk->size >> 8) & 0xFF;
|
|
data[3] = chunk->size & 0xFF;
|
|
data[4] = 'i';
|
|
data[5] = 'T';
|
|
data[6] = 'X';
|
|
data[7] = 't';
|
|
crc = metadatamux_calc_crc (data + 4, chunk->size + 4);
|
|
data[chunk->size + 8] = (crc >> 24) & 0xFF;
|
|
data[chunk->size + 9] = (crc >> 16) & 0xFF;
|
|
data[chunk->size + 10] = (crc >> 8) & 0xFF;
|
|
data[chunk->size + 11] = crc & 0xFF;
|
|
|
|
chunk->size += 12;
|
|
|
|
}
|