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fpexif: Fix incorrect copying of XMP meta data when a file with XMP is re-saved.

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git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@7983 8e941d3f-bd1b-0410-a28a-d453659cc2b4
This commit is contained in:
wp_xxyyzz
2021-03-25 13:16:46 +00:00
parent d6e6b78c99
commit 5c636d346d
2 changed files with 23 additions and 32 deletions
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2
components/fpexif/fpeexifreadwrite.pas
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@ -803,7 +803,7 @@ begin
FExifSegmentStartPos := AStream.Position;
AStream.WriteBuffer(SEGMENT_MARKER[0], 2);
// Next two zero bytes are the size of the entire Exif segiment, they will be
// replaced when the segment is completely written. For this, we store the
// replaced when the segment is completely written. For this, we stored the
// offset to the beginning of the EXIF segment in FExifSegmentStartPos.
AStream.WriteBuffer(SIZE, 2);
AStream.WriteBuffer(EXIF_SIGNATURE[0], 6);

53
components/fpexif/fpemetadata.pas
View File

@ -230,7 +230,7 @@ begin
AStream.Position := startPos;
// ... and write the segment size.
w := BEToN(segmentSize);
w := NToBE(segmentSize);
AStream.WriteBuffer(w, SizeOf(w));
// Rewind stream to the end
@ -393,18 +393,16 @@ type
TSegmentHeader = packed record
Key: byte;
Marker: byte;
Size: Word;
Size: Word; // total size of the segment without "Key" and "Marker", but with "Size"
end;
const
SOI_MARKER: array[0..1] of byte = ($FF, $D8);
XMP_SIGNATURE = 'http://ns.adobe.com/xap/1.0/';
var
header: TSegmentHeader;
headerSize, newHeaderSize: Word;
headerSize: Word;
n, count: Int64;
savedPos: Int64;
jfif: TJpegJFIFSegment;
s: String;
s: RawByteString;
begin
// Write the header segment and all metadata segments stored in TImgInfo
// to the beginning of the stream
@ -424,10 +422,8 @@ begin
// Some images do not specify the segment length correctly and fill the
// space to the next segment with zero bytes.
if LongInt(header) = 0 then begin
n := 0;
while AInputStream.ReadByte = 0 do
inc(n);
if (header.Key = 0) then begin
repeat until AInputStream.ReadByte = $FF;
AInputStream.Position := AInputStream.Position - 1;
n := AInputStream.Read(header, SizeOf(Header));
if n <> SizeOf(Header) then
@ -438,39 +434,32 @@ begin
Error(rsJpegSegmentMarkerExpected);
headerSize := BEToN(header.Size);
// Save stream position before segment size value.
// Stream position at start of segment header
savedPos := AInputStream.Position - SizeOf(header);
// Save stream position after marker bytes, i.e. at begin of segment size value.
savedPos := AInputStream.Position - 2;
case header.Marker of
M_SOI:
headerSize := 0;
M_JFIF, M_IPTC, M_COM: // These segments were already written by WriteJpeg
;
M_EXIF:
// there may be also the XMP segment which has the same key $E1.
begin
// XMP segment found which has the same key $E1 as the normal EXIF segment.
SetLength(s, Length(XMP_SIGNATURE));
AInputStream.Read(s[1], Length(XMP_SIGNATURE));
if s = XMP_SIGNATURE then
begin
// XMP segment found --> write it back as it is (needs to be fixed to write current meta data)
newHeaderSize := (Trunc(headerSize / 256) + 1) * 256 - SizeOf(header);
SetLength(s, newHeaderSize - Length(XMP_SIGNATURE));
FillChar(s[1], Length(s), 0);
AInputStream.Read(s[1], headerSize);
header.Size := NToBE(newHeaderSize);
AOutputStream.Write(header, SizeOf(Header));
AOutputStream.Write(XMP_SIGNATURE, Length(XMP_SIGNATURE));
AOutputStream.Write(s[1], Length(s));
{
AInputStream.Position := savedPos - 4;
n := AOutputStream.CopyFrom(AInputStream, Int64(header.Size) + 2);
if n <> Int64(header.Size) + 2 then
// Return to where the segment begins
AInputStream.Position := savedPos - 2;
// Copy entire segment incl header
n := AOutputStream.CopyFrom(AInputStream, headerSize + 2);
if n <> Int64(headerSize) + 2 then
Error(rsJpegReadWriteErrorInSegment);
}
end
else
end else
begin
// EXIF segment found. But this already has been written by WriteJpeg -> nothing to do
// Normal EXIF segment found. But this already has been written by WriteJpeg -> nothing to do
end;
end;
M_SOS:
@ -479,14 +468,16 @@ begin
// --> just copy the rest of the file
count := AInputStream.Size - savedPos;
AInputStream.Position := savedPos;
AOutputStream.WriteBuffer(header, 2);
AOutputStream.Write(header, 2);
n := AOutputStream.CopyFrom(AInputStream, count);
if n <> count then
Error(rsJpegCompressedDataWriting);
break;
end;
else
AInputStream.Position := AInputStream.Position - 4; // go back to where the segment begins
// Return to where the segment begins
AInputStream.Position := AInputStream.Position - 4;
// Copy entire segment incl header
n := AOutputStream.CopyFrom(AInputStream, headerSize + 2);
if n <> Int64(headerSize) + 2 then
Error(rsJpegReadWriteErrorInSegment);