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tags: exif: Fix inner tags offset rewriting

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Fixes a bug that made exif helper lib fail to rewrite inner ifd tags
offsets when there were more than 1 inner ifd.
This commit is contained in:
Thiago Santos 2010-08-09 17:25:07 -03:00
parent 90a79b4c60
commit 4a42d3b0ce
1 changed files with 60 additions and 31 deletions
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91
gst-libs/gst/tag/gstexiftag.c
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@ -511,26 +511,46 @@ tagdata_copy (GstExifTagData * to, const GstExifTagData * from)
}
static void
gst_exif_tag_rewrite_offsets (GstExifWriter * writer, guint32 base_offset)
gst_exif_tag_rewrite_offsets (GstByteWriter * writer, gint byte_order,
guint32 offset, gint num_tags, GstByteWriter * inner_ifds_data)
{
guint32 offset;
GstByteReader *reader;
gint i;
guint16 aux = -1;
GST_LOG ("Rewriting tag entries offsets");
offset = gst_byte_writer_get_size (&writer->tagwriter);
while (gst_byte_writer_get_pos (&writer->tagwriter) <
gst_byte_writer_get_size (&writer->tagwriter)) {
reader = (GstByteReader *) writer;
if (num_tags == -1) {
if (byte_order == G_LITTLE_ENDIAN) {
gst_byte_reader_get_uint16_le (reader, &aux);
} else {
gst_byte_reader_get_uint16_be (reader, &aux);
}
if (aux == -1) {
GST_WARNING ("Failed to read number of tags, won't rewrite offsets");
return;
}
num_tags = (gint) aux;
}
g_return_if_fail (num_tags != -1);
GST_DEBUG ("number of tags %d", num_tags);
for (i = 0; i < num_tags; i++) {
guint16 type = 0;
guint32 cur_offset = 0;
GstByteReader *reader;
gint byte_size = 0;
guint32 count = 0;
guint16 tag_id = 0;
reader = (GstByteReader *) & writer->tagwriter;
g_assert (gst_byte_writer_get_pos (writer) <
gst_byte_writer_get_size (writer));
/* read the type */
if (writer->byte_order == G_LITTLE_ENDIAN) {
if (byte_order == G_LITTLE_ENDIAN) {
if (!gst_byte_reader_get_uint16_le (reader, &tag_id))
break;
if (!gst_byte_reader_get_uint16_le (reader, &type))
@ -546,6 +566,8 @@ gst_exif_tag_rewrite_offsets (GstExifWriter * writer, guint32 base_offset)
break;
}
GST_LOG ("Parsed tag %x of type %u and count %u", tag_id, type, count);
switch (type) {
case EXIF_TYPE_BYTE:
case EXIF_TYPE_ASCII:
@ -570,25 +592,36 @@ gst_exif_tag_rewrite_offsets (GstExifWriter * writer, guint32 base_offset)
/* adjust the offset if needed */
if (byte_size > 4 || tag_id == EXIF_GPS_IFD_TAG || tag_id == EXIF_IFD_TAG) {
if (writer->byte_order == G_LITTLE_ENDIAN) {
if (byte_order == G_LITTLE_ENDIAN) {
if (gst_byte_reader_peek_uint32_le (reader, &cur_offset)) {
gst_byte_writer_put_uint32_le (&writer->tagwriter,
cur_offset + offset + base_offset);
gst_byte_writer_put_uint32_le (writer, cur_offset + offset);
}
} else {
if (gst_byte_reader_peek_uint32_be (reader, &cur_offset)) {
gst_byte_writer_put_uint32_be (&writer->tagwriter,
cur_offset + offset + base_offset);
gst_byte_writer_put_uint32_be (writer, cur_offset + offset);
}
}
GST_DEBUG ("Rewriting tag offset from %u to (%u + %u + %u) %u",
cur_offset, cur_offset, offset, base_offset,
cur_offset + offset + base_offset);
GST_DEBUG ("Rewriting tag offset from %u to (%u + %u) %u",
cur_offset, cur_offset, offset, cur_offset + offset);
if ((tag_id == EXIF_GPS_IFD_TAG || tag_id == EXIF_IFD_TAG) &&
inner_ifds_data != NULL) {
/* needs special handling */
if (!gst_byte_writer_set_pos (inner_ifds_data, cur_offset)) {
GST_WARNING ("Failed to position writer to rewrite inner ifd "
"offsets");
continue;
}
gst_exif_tag_rewrite_offsets (inner_ifds_data, byte_order, offset, -1,
NULL);
}
} else {
gst_byte_reader_skip (reader, 4);
GST_DEBUG ("No need to rewrite tag offset");
}
}
GST_LOG ("Done rewriting offsets");
}
static void
@ -738,17 +771,9 @@ write_exif_ifd (const GstTagList * taglist, gboolean byte_order,
}
if (inner_tag_map) {
/* The base offset for this inner ifd is the sum of:
* - the current base offset
* - the total tag data of current this ifd
* - the total data of the current ifd
* - its own tag entry length still to be writen (12)
* - 4 bytes for the next ifd entry still to be writen
*/
inner_ifd = write_exif_ifd (taglist, byte_order, base_offset +
gst_byte_writer_get_size (&writer.tagwriter) +
gst_byte_writer_get_size (&writer.datawriter) + 12 + 4,
inner_tag_map);
/* base offset and tagheader size are added when rewriting offset */
inner_ifd = write_exif_ifd (taglist, byte_order,
gst_byte_writer_get_size (&writer.datawriter), inner_tag_map);
}
if (inner_ifd) {
@ -782,8 +807,12 @@ write_exif_ifd (const GstTagList * taglist, gboolean byte_order,
else
gst_byte_writer_put_uint16_be (&writer.tagwriter, writer.tags_total);
GST_DEBUG ("Number of tags rewriten to %d", writer.tags_total);
/* now that we know the tag headers size, we can add the offsets */
gst_exif_tag_rewrite_offsets (&writer, base_offset);
gst_exif_tag_rewrite_offsets (&writer.tagwriter, writer.byte_order,
base_offset + gst_byte_writer_get_size (&writer.tagwriter),
writer.tags_total, &writer.datawriter);
return gst_exif_writer_reset_and_get_buffer (&writer);
}
@ -853,9 +882,9 @@ parse_exif_ifd (GstExifReader * exif_reader, gint buf_offset,
if (!parse_exif_tag_header (&reader, exif_reader->byte_order, &tagdata))
goto read_error;
GST_DEBUG ("Parsed tag: id 0x%x, type %u, count %u, offset %u (0x%x)",
tagdata.tag, tagdata.tag_type, tagdata.count, tagdata.offset,
tagdata.offset);
GST_DEBUG ("Parsed tag: id 0x%x, type %u, count %u, offset %u (0x%x)"
", buf size: %u", tagdata.tag, tagdata.tag_type, tagdata.count,
tagdata.offset, tagdata.offset, gst_byte_reader_get_size (&reader));
map_index = exif_tag_map_find_reverse (tagdata.tag, tag_map, TRUE);
if (map_index == -1) {