/// <summary>
/// Reads the APP1 section containing Exif metadata.
/// </summary>
private void ReadAPP1()
{
// Find the APP1 section containing Exif metadata
app1 = file.Sections.Find(a => (a.Marker == JPEGMarker.APP1) &&
(Encoding.ASCII.GetString(a.Header, 0, 6) == "Exif\0\0"));
// If there is no APP1 section, add a new one after the last APP0 section (if any).
if (app1 == null)
{
int insertionIndex = file.Sections.FindLastIndex(a => a.Marker == JPEGMarker.APP0);
if (insertionIndex == -1)
{
insertionIndex = 0;
}
insertionIndex++;
ByteOrder = BitConverterEx.ByteOrder.BigEndian;
app1 = new JPEGSection(JPEGMarker.APP1);
file.Sections.Insert(insertionIndex, app1);
return;
}
//#if DEBUG
// mMap = new MemoryBinStream();
// mMap.Seek(0, SeekOrigin.Begin);
// mMap.Write(new Bin("Exif Marker", 3, 6));
//#endif
byte[] header = app1.Header;
SortedList <int, IFD> ifdqueue = new SortedList <int, IFD>();
makerNoteOffset = 0;
// TIFF header
int tiffoffset = 6;
if (header[tiffoffset] == 0x49)
{
ByteOrder = BitConverterEx.ByteOrder.LittleEndian;
}
else
{
ByteOrder = BitConverterEx.ByteOrder.BigEndian;
}
BitConverterEx conv = new BitConverterEx(ByteOrder, BitConverterEx.ByteOrder.System);
// Offset to 0th IFD
int ifd0offset = (int)conv.ToUInt32(header, tiffoffset + 4);
ifdqueue.Add(ifd0offset, IFD.Zeroth);
int thumboffset = -1;
int thumblength = 0;
int thumbtype = -1;
#if DEBUG
mMap.Write(new Bin("Byte Order: " + ByteOrder.ToString(), 4, 2));
mMap.Write(new Bin("TIFF ID: 0x00, 0x2A", 4, 2));
mMap.Write(new Bin("Offset to 0th IFD: " + ifd0offset.ToString(), 4, 4));
#endif
// Read IFDs
while (ifdqueue.Count != 0)
{
int ifdoffset = tiffoffset + ifdqueue.Keys[0];
IFD currentifd = ifdqueue.Values[0];
ifdqueue.RemoveAt(0);
// Field count
ushort fieldcount = conv.ToUInt16(header, ifdoffset);
#if DEBUG
mMap.Seek(ifdoffset, SeekOrigin.Begin);
mMap.Write(new Bin(currentifd.ToString() + " IFD Field Count: " + fieldcount.ToString(), 5, 2));
#endif
for (short i = 0; i < fieldcount; i++)
{
// Read field info
int fieldoffset = ifdoffset + 2 + 12 * i;
ushort tag = conv.ToUInt16(header, fieldoffset);
ushort type = conv.ToUInt16(header, fieldoffset + 2);
uint count = conv.ToUInt32(header, fieldoffset + 4);
byte[] value = new byte[4];
Array.Copy(header, fieldoffset + 8, value, 0, 4);
// Fields containing offsets to other IFDs
if (currentifd == IFD.Zeroth && tag == 0x8769)
{
int exififdpointer = (int)conv.ToUInt32(value, 0);
ifdqueue.Add(exififdpointer, IFD.EXIF);
}
else if (currentifd == IFD.Zeroth && tag == 0x8825)
{
int gpsifdpointer = (int)conv.ToUInt32(value, 0);
ifdqueue.Add(gpsifdpointer, IFD.GPS);
}
else if (currentifd == IFD.EXIF && tag == 0xa005)
{
int interopifdpointer = (int)conv.ToUInt32(value, 0);
ifdqueue.Add(interopifdpointer, IFD.Interop);
}
// Save the offset to maker note data
if (currentifd == IFD.EXIF && tag == 37500)
{
makerNoteOffset = conv.ToUInt32(value, 0);
}
// Calculate the bytes we need to read
uint baselength = 0;
if (type == 1 || type == 2 || type == 7)
{
baselength = 1;
}
else if (type == 3)
{
baselength = 2;
}
else if (type == 4 || type == 9)
{
baselength = 4;
}
else if (type == 5 || type == 10)
{
baselength = 8;
}
uint totallength = count * baselength;
// If field value does not fit in 4 bytes
// the value field is an offset to the actual
// field value
int fieldposition = 0;
if (totallength > 4)
{
fieldposition = tiffoffset + (int)conv.ToUInt32(value, 0);
value = new byte[totallength];
Array.Copy(header, fieldposition, value, 0, totallength);
}
// Compressed thumbnail data
if (currentifd == IFD.First && tag == 0x201)
{
thumbtype = 0;
thumboffset = (int)conv.ToUInt32(value, 0);
}
else if (currentifd == IFD.First && tag == 0x202)
{
thumblength = (int)conv.ToUInt32(value, 0);
}
// Uncompressed thumbnail data
if (currentifd == IFD.First && tag == 0x111)
{
thumbtype = 1;
// Offset to first strip
if (type == 3)
{
thumboffset = (int)conv.ToUInt16(value, 0);
}
else
{
thumboffset = (int)conv.ToUInt32(value, 0);
}
}
else if (currentifd == IFD.First && tag == 0x117)
{
thumblength = 0;
for (int j = 0; j < count; j++)
{
if (type == 3)
{
thumblength += (int)conv.ToUInt16(value, 0);
}
else
{
thumblength += (int)conv.ToUInt32(value, 0);
}
}
}
// Create the exif property from the interop data
ExifProperty prop = ExifPropertyFactory.Get(tag, type, count, value, ByteOrder, currentifd);
Properties.Add(prop.Tag, prop);
#if DEBUG
mMap.Seek(fieldoffset, SeekOrigin.Begin);
mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " ID: " + tag.ToString(), 6, 2, prop));
mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Type: " + type.ToString(), 6, 2, prop));
mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Count: " + count.ToString(), 6, 4, prop));
mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Value: " + string.Format("[0x{0:x2}, 0x{1:x2}, 0x{2:x2}, 0x{3:x2}]", value[0], value[1], value[2], value[3]), 6, 4, prop));
if (totallength > 4)
{
mMap.Seek(fieldposition, SeekOrigin.Begin);
mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Data", 7, totallength, prop));
}
#endif
}
// 1st IFD pointer
int firstifdpointer = (int)conv.ToUInt32(header, ifdoffset + 2 + 12 * fieldcount);
if (firstifdpointer != 0)
{
ifdqueue.Add(firstifdpointer, IFD.First);
}
#if DEBUG
mMap.Seek(ifdoffset + 2 + 12 * fieldcount, SeekOrigin.Begin);
mMap.Write(new Bin("1st IFD Pointer: " + firstifdpointer.ToString(), 5, 4));
#endif
// Read thumbnail
if (thumboffset != -1 && thumblength != 0 && Thumbnail == null)
{
if (thumbtype == 0)
{
using (MemoryStream ts = new MemoryStream(header, tiffoffset + thumboffset, thumblength))
{
Thumbnail = new JPEGFile(ts);
}
}
#if DEBUG
mMap.Seek(tiffoffset + thumboffset, SeekOrigin.Begin);
mMap.Write(new Bin("Thumbnail", 8, thumblength));
#endif
}
}
}
/// <summary>
/// Reads the APP1 section containing Exif metadata.
/// </summary>
private void ReadAPP1()
{
// Find the APP1 section containing Exif metadata
app1 = file.Sections.Find(a => (a.Marker == JPEGMarker.APP1) &&
(Encoding.ASCII.GetString(a.Header, 0, 6) == "Exif\0\0"));
// If there is no APP1 section, add a new one after the last APP0 section (if any).
if (app1 == null)
{
int insertionIndex = file.Sections.FindLastIndex(a => a.Marker == JPEGMarker.APP0);
if (insertionIndex == -1) insertionIndex = 0;
insertionIndex++;
ByteOrder = BitConverterEx.ByteOrder.BigEndian;
app1 = new JPEGSection(JPEGMarker.APP1);
file.Sections.Insert(insertionIndex, app1);
return;
}
#if DEBUG
mMap = new MemoryBinStream();
mMap.Seek(0, SeekOrigin.Begin);
mMap.Write(new Bin("Exif Marker", 3, 6));
#endif
byte[] header = app1.Header;
SortedList<int, IFD> ifdqueue = new SortedList<int, IFD>();
makerNoteOffset = 0;
// TIFF header
int tiffoffset = 6;
if (header[tiffoffset] == 0x49)
ByteOrder = BitConverterEx.ByteOrder.LittleEndian;
else
ByteOrder = BitConverterEx.ByteOrder.BigEndian;
BitConverterEx conv = new BitConverterEx(ByteOrder, BitConverterEx.ByteOrder.System);
// Offset to 0th IFD
int ifd0offset = (int)conv.ToUInt32(header, tiffoffset + 4);
ifdqueue.Add(ifd0offset, IFD.Zeroth);
int thumboffset = -1;
int thumblength = 0;
int thumbtype = -1;
#if DEBUG
mMap.Write(new Bin("Byte Order: " + ByteOrder.ToString(), 4, 2));
mMap.Write(new Bin("TIFF ID: 0x00, 0x2A", 4, 2));
mMap.Write(new Bin("Offset to 0th IFD: " + ifd0offset.ToString(), 4, 4));
#endif
// Read IFDs
while (ifdqueue.Count != 0)
{
int ifdoffset = tiffoffset + ifdqueue.Keys[0];
IFD currentifd = ifdqueue.Values[0];
ifdqueue.RemoveAt(0);
// Field count
ushort fieldcount = conv.ToUInt16(header, ifdoffset);
#if DEBUG
mMap.Seek(ifdoffset, SeekOrigin.Begin);
mMap.Write(new Bin(currentifd.ToString() + " IFD Field Count: " + fieldcount.ToString(), 5, 2));
#endif
for (short i = 0; i < fieldcount; i++)
{
// Read field info
int fieldoffset = ifdoffset + 2 + 12 * i;
ushort tag = conv.ToUInt16(header, fieldoffset);
ushort type = conv.ToUInt16(header, fieldoffset + 2);
uint count = conv.ToUInt32(header, fieldoffset + 4);
byte[] value = new byte[4];
Array.Copy(header, fieldoffset + 8, value, 0, 4);
// Fields containing offsets to other IFDs
if (currentifd == IFD.Zeroth && tag == 0x8769)
{
int exififdpointer = (int)conv.ToUInt32(value, 0);
ifdqueue.Add(exififdpointer, IFD.EXIF);
}
else if (currentifd == IFD.Zeroth && tag == 0x8825)
{
int gpsifdpointer = (int)conv.ToUInt32(value, 0);
ifdqueue.Add(gpsifdpointer, IFD.GPS);
}
else if (currentifd == IFD.EXIF && tag == 0xa005)
{
int interopifdpointer = (int)conv.ToUInt32(value, 0);
ifdqueue.Add(interopifdpointer, IFD.Interop);
}
// Save the offset to maker note data
if (currentifd == IFD.EXIF && tag == 37500)
makerNoteOffset = conv.ToUInt32(value, 0);
// Calculate the bytes we need to read
uint baselength = 0;
if (type == 1 || type == 2 || type == 7)
baselength = 1;
else if (type == 3)
baselength = 2;
else if (type == 4 || type == 9)
baselength = 4;
else if (type == 5 || type == 10)
baselength = 8;
uint totallength = count * baselength;
// If field value does not fit in 4 bytes
// the value field is an offset to the actual
// field value
int fieldposition = 0;
if (totallength > 4)
{
fieldposition = tiffoffset + (int)conv.ToUInt32(value, 0);
value = new byte[totallength];
Array.Copy(header, fieldposition, value, 0, totallength);
}
// Compressed thumbnail data
if (currentifd == IFD.First && tag == 0x201)
{
thumbtype = 0;
thumboffset = (int)conv.ToUInt32(value, 0);
}
else if (currentifd == IFD.First && tag == 0x202)
thumblength = (int)conv.ToUInt32(value, 0);
// Uncompressed thumbnail data
if (currentifd == IFD.First && tag == 0x111)
{
thumbtype = 1;
// Offset to first strip
if (type == 3)
thumboffset = (int)conv.ToUInt16(value, 0);
else
thumboffset = (int)conv.ToUInt32(value, 0);
}
else if (currentifd == IFD.First && tag == 0x117)
{
thumblength = 0;
for (int j = 0; j < count; j++)
{
if (type == 3)
thumblength += (int)conv.ToUInt16(value, 0);
else
thumblength += (int)conv.ToUInt32(value, 0);
}
}
// Create the exif property from the interop data
ExifProperty prop = ExifPropertyFactory.Get(tag, type, count, value, ByteOrder, currentifd);
Properties.Add(prop.Tag, prop);
#if DEBUG
mMap.Seek(fieldoffset, SeekOrigin.Begin);
mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " ID: " + tag.ToString(), 6, 2, prop));
mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Type: " + type.ToString(), 6, 2, prop));
mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Count: " + count.ToString(), 6, 4, prop));
mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Value: " + string.Format("[0x{0:x2}, 0x{1:x2}, 0x{2:x2}, 0x{3:x2}]", value[0], value[1], value[2], value[3]), 6, 4, prop));
if (totallength > 4)
{
mMap.Seek(fieldposition, SeekOrigin.Begin);
mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Data", 7, totallength, prop));
}
#endif
}
// 1st IFD pointer
int firstifdpointer = (int)conv.ToUInt32(header, ifdoffset + 2 + 12 * fieldcount);
if (firstifdpointer != 0)
ifdqueue.Add(firstifdpointer, IFD.First);
#if DEBUG
mMap.Seek(ifdoffset + 2 + 12 * fieldcount, SeekOrigin.Begin);
mMap.Write(new Bin("1st IFD Pointer: " + firstifdpointer.ToString(), 5, 4));
#endif
// Read thumbnail
if (thumboffset != -1 && thumblength != 0 && Thumbnail == null)
{
if (thumbtype == 0)
{
using (MemoryStream ts = new MemoryStream(header, tiffoffset + thumboffset, thumblength))
{
Thumbnail = new JPEGFile(ts);
}
}
#if DEBUG
mMap.Seek(tiffoffset + thumboffset, SeekOrigin.Begin);
mMap.Write(new Bin("Thumbnail", 8, thumblength));
#endif
}
}
}