Ejemplo n.º 1
0
        /// <summary>
        /// Reads the APP0 section containing JFIF extension metadata.
        /// </summary>
        private void ReadJFXXAPP0()
        {
            // Find the APP0 section containing JFIF metadata
            jfxxApp0 = Sections.Find(a => (a.Marker == JPEGMarker.APP0) &&
                                     a.Header.Length >= 5 &&
                                     (Encoding.ASCII.GetString(a.Header, 0, 5) == "JFXX\0"));

            // If there is no APP0 section, return.
            if (jfxxApp0 == null)
            {
                return;
            }

            byte[] header = jfxxApp0.Header;

            // Version
            JFIFExtension version = (JFIFExtension)header[5];

            Properties.Add(new ExifEnumProperty <JFIFExtension>(ExifTag.JFXXExtensionCode, version));

            // Read thumbnail
            if (version == JFIFExtension.ThumbnailJPEG)
            {
                byte[] data = new byte[header.Length - 6];
                Array.Copy(header, 6, data, 0, data.Length);
                Properties.Add(new JFIFThumbnailProperty(ExifTag.JFXXThumbnail, new JFIFThumbnail(JFIFThumbnail.ImageFormat.JPEG, data)));
            }
            else if (version == JFIFExtension.Thumbnail24BitRGB)
            {
                // Thumbnails pixel count
                byte xthumbnail = header[6];
                Properties.Add(new ExifByte(ExifTag.JFXXXThumbnail, xthumbnail));
                byte ythumbnail = header[7];
                Properties.Add(new ExifByte(ExifTag.JFXXYThumbnail, ythumbnail));
                byte[] data = new byte[3 * xthumbnail * ythumbnail];
                Array.Copy(header, 8, data, 0, data.Length);
                Properties.Add(new JFIFThumbnailProperty(ExifTag.JFXXThumbnail, new JFIFThumbnail(JFIFThumbnail.ImageFormat.BMP24Bit, data)));
            }
            else if (version == JFIFExtension.ThumbnailPaletteRGB)
            {
                // Thumbnails pixel count
                byte xthumbnail = header[6];
                Properties.Add(new ExifByte(ExifTag.JFXXXThumbnail, xthumbnail));
                byte ythumbnail = header[7];
                Properties.Add(new ExifByte(ExifTag.JFXXYThumbnail, ythumbnail));
                byte[] palette = new byte[768];
                Array.Copy(header, 8, palette, 0, palette.Length);
                byte[] data = new byte[xthumbnail * ythumbnail];
                Array.Copy(header, 8 + 768, data, 0, data.Length);
                Properties.Add(new JFIFThumbnailProperty(ExifTag.JFXXThumbnail, new JFIFThumbnail(palette, data)));
            }
        }
Ejemplo n.º 2
0
        /// <summary>
        /// Reads the APP0 section containing JFIF metadata.
        /// </summary>
        private void ReadJFIFAPP0()
        {
            // Find the APP0 section containing JFIF metadata
            jfifApp0 = Sections.Find(a => (a.Marker == JPEGMarker.APP0) &&
                                     a.Header.Length >= 5 &&
                                     (Encoding.ASCII.GetString(a.Header, 0, 5) == "JFIF\0"));

            // If there is no APP0 section, return.
            if (jfifApp0 == null)
            {
                return;
            }

            byte[]         header   = jfifApp0.Header;
            BitConverterEx jfifConv = BitConverterEx.BigEndian;

            // Version
            ushort version = jfifConv.ToUInt16(header, 5);

            Properties.Add(new JFIFVersion(ExifTag.JFIFVersion, version));

            // Units
            byte unit = header[7];

            Properties.Add(new ExifEnumProperty <JFIFDensityUnit>(ExifTag.JFIFUnits, (JFIFDensityUnit)unit));

            // X and Y densities
            ushort xdensity = jfifConv.ToUInt16(header, 8);

            Properties.Add(new ExifUShort(ExifTag.XDensity, xdensity));
            ushort ydensity = jfifConv.ToUInt16(header, 10);

            Properties.Add(new ExifUShort(ExifTag.YDensity, ydensity));

            // Thumbnails pixel count
            byte xthumbnail = header[12];

            Properties.Add(new ExifByte(ExifTag.JFIFXThumbnail, xthumbnail));
            byte ythumbnail = header[13];

            Properties.Add(new ExifByte(ExifTag.JFIFYThumbnail, ythumbnail));

            // Read JFIF thumbnail
            int n = xthumbnail * ythumbnail;

            byte[] jfifThumbnail = new byte[n];
            Array.Copy(header, 14, jfifThumbnail, 0, n);
            Properties.Add(new JFIFThumbnailProperty(ExifTag.JFIFThumbnail, new JFIFThumbnail(JFIFThumbnail.ImageFormat.JPEG, jfifThumbnail)));
        }
Ejemplo n.º 3
0
        /// <summary>
        /// Initializes a new instance of the <see cref="ExifFile"/> class.
        /// </summary>
        /// <param name="stream">A <see cref="Sytem.IO.Stream"/> that contains image data.</param>
        /// <param name="encoding">The encoding to be used for text metadata when the source encoding is unknown.</param>
        protected internal JPEGFile(Stream stream, Encoding encoding)
        {
            Format       = ImageFileFormat.JPEG;
            Sections     = new List <JPEGSection>();
            TrailingData = new byte[0];
            Encoding     = encoding;

            stream.Seek(0, SeekOrigin.Begin);

            // Read the Start of Image (SOI) marker. SOI marker is represented
            // with two bytes: 0xFF, 0xD8.
            byte[] markerbytes = new byte[2];
            if (stream.Read(markerbytes, 0, 2) != 2 || markerbytes[0] != 0xFF || markerbytes[1] != 0xD8)
            {
                throw new NotValidJPEGFileException();
            }
            stream.Seek(0, SeekOrigin.Begin);

            // Search and read sections until we reach the end of file.
            while (stream.Position != stream.Length)
            {
                // Read the next section marker. Section markers are two bytes
                // with values 0xFF, 0x?? where ?? must not be 0x00 or 0xFF.
                if (stream.Read(markerbytes, 0, 2) != 2 || markerbytes[0] != 0xFF || markerbytes[1] == 0x00 || markerbytes[1] == 0xFF)
                {
                    throw new NotValidJPEGFileException();
                }

                JPEGMarker marker = (JPEGMarker)markerbytes[1];

                byte[] header = new byte[0];
                // SOI, EOI and RST markers do not contain any header
                if (marker != JPEGMarker.SOI && marker != JPEGMarker.EOI && !(marker >= JPEGMarker.RST0 && marker <= JPEGMarker.RST7))
                {
                    // Length of the header including the length bytes.
                    // This value is a 16-bit unsigned integer
                    // in big endian byte-order.
                    byte[] lengthbytes = new byte[2];
                    if (stream.Read(lengthbytes, 0, 2) != 2)
                    {
                        throw new NotValidJPEGFileException();
                    }
                    long length = (long)BitConverterEx.BigEndian.ToUInt16(lengthbytes, 0);

                    // Read section header.
                    header = new byte[length - 2];
                    int bytestoread = header.Length;
                    while (bytestoread > 0)
                    {
                        int count     = Math.Min(bytestoread, 4 * 1024);
                        int bytesread = stream.Read(header, header.Length - bytestoread, count);
                        if (bytesread == 0)
                        {
                            throw new NotValidJPEGFileException();
                        }
                        bytestoread -= bytesread;
                    }
                }

                // Start of Scan (SOS) sections and RST sections are immediately
                // followed by entropy coded data. For that, we need to read until
                // the next section marker once we reach a SOS or RST.
                byte[] entropydata = new byte[0];
                if (marker == JPEGMarker.SOS || (marker >= JPEGMarker.RST0 && marker <= JPEGMarker.RST7))
                {
                    long position = stream.Position;

                    // Search for the next section marker
                    while (true)
                    {
                        // Search for an 0xFF indicating start of a marker
                        int nextbyte = 0;
                        do
                        {
                            nextbyte = stream.ReadByte();
                            if (nextbyte == -1)
                            {
                                throw new NotValidJPEGFileException();
                            }
                        } while ((byte)nextbyte != 0xFF);

                        // Skip filler bytes (0xFF)
                        do
                        {
                            nextbyte = stream.ReadByte();
                            if (nextbyte == -1)
                            {
                                throw new NotValidJPEGFileException();
                            }
                        } while ((byte)nextbyte == 0xFF);

                        // Looks like a section marker. The next byte must not be 0x00.
                        if ((byte)nextbyte != 0x00)
                        {
                            // We reached a section marker. Calculate the
                            // length of the entropy coded data.
                            stream.Seek(-2, SeekOrigin.Current);
                            long edlength = stream.Position - position;
                            stream.Seek(-edlength, SeekOrigin.Current);

                            // Read entropy coded data
                            entropydata = new byte[edlength];
                            int bytestoread = entropydata.Length;
                            while (bytestoread > 0)
                            {
                                int count     = Math.Min(bytestoread, 4 * 1024);
                                int bytesread = stream.Read(entropydata, entropydata.Length - bytestoread, count);
                                if (bytesread == 0)
                                {
                                    throw new NotValidJPEGFileException();
                                }
                                bytestoread -= bytesread;
                            }

                            break;
                        }
                    }
                }

                // Store section.
                JPEGSection section = new JPEGSection(marker, header, entropydata);
                Sections.Add(section);

                // Some propriety formats store data past the EOI marker
                if (marker == JPEGMarker.EOI)
                {
                    int bytestoread = (int)(stream.Length - stream.Position);
                    TrailingData = new byte[bytestoread];
                    while (bytestoread > 0)
                    {
                        int count     = (int)Math.Min(bytestoread, 4 * 1024);
                        int bytesread = stream.Read(TrailingData, TrailingData.Length - bytestoread, count);
                        if (bytesread == 0)
                        {
                            throw new NotValidJPEGFileException();
                        }
                        bytestoread -= bytesread;
                    }
                }
            }

            // Read metadata sections
            ReadJFIFAPP0();
            ReadJFXXAPP0();
            ReadExifAPP1();

            // Process the maker note
            makerNoteProcessed = false;
        }
Ejemplo n.º 4
0
        /// <summary>
        /// Reads the APP1 section containing Exif metadata.
        /// </summary>
        private void ReadExifAPP1()
        {
            // Find the APP1 section containing Exif metadata
            exifApp1 = Sections.Find(a => (a.Marker == JPEGMarker.APP1) &&
                                     a.Header.Length >= 6 &&
                                     (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 (exifApp1 == null)
            {
                int insertionIndex = Sections.FindLastIndex(a => a.Marker == JPEGMarker.APP0);
                if (insertionIndex == -1)
                {
                    insertionIndex = 0;
                }
                insertionIndex++;
                exifApp1 = new JPEGSection(JPEGMarker.APP1);
                Sections.Insert(insertionIndex, exifApp1);
                if (BitConverterEx.SystemByteOrder == BitConverterEx.ByteOrder.LittleEndian)
                {
                    ByteOrder = BitConverterEx.ByteOrder.LittleEndian;
                }
                else
                {
                    ByteOrder = BitConverterEx.ByteOrder.BigEndian;
                }
                return;
            }

            byte[] header = exifApp1.Header;
            SortedList <int, IFD> ifdqueue = new SortedList <int, IFD>();

            makerNoteOffset = 0;

            // TIFF header
            int tiffoffset = 6;

            if (header[tiffoffset] == 0x49 && header[tiffoffset + 1] == 0x49)
            {
                ByteOrder = BitConverterEx.ByteOrder.LittleEndian;
            }
            else if (header[tiffoffset] == 0x4D && header[tiffoffset + 1] == 0x4D)
            {
                ByteOrder = BitConverterEx.ByteOrder.BigEndian;
            }
            else
            {
                throw new NotValidExifFileException();
            }

            // TIFF header may have a different byte order
            BitConverterEx.ByteOrder tiffByteOrder = ByteOrder;
            if (BitConverterEx.LittleEndian.ToUInt16(header, tiffoffset + 2) == 42)
            {
                tiffByteOrder = BitConverterEx.ByteOrder.LittleEndian;
            }
            else if (BitConverterEx.BigEndian.ToUInt16(header, tiffoffset + 2) == 42)
            {
                tiffByteOrder = BitConverterEx.ByteOrder.BigEndian;
            }
            else
            {
                throw new NotValidExifFileException();
            }

            // Offset to 0th IFD
            int ifd0offset = (int)BitConverterEx.ToUInt32(header, tiffoffset + 4, tiffByteOrder, BitConverterEx.SystemByteOrder);

            ifdqueue.Add(ifd0offset, IFD.Zeroth);

            BitConverterEx conv        = new BitConverterEx(ByteOrder, BitConverterEx.SystemByteOrder);
            int            thumboffset = -1;
            int            thumblength = 0;
            int            thumbtype   = -1;

            // 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);
                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, Encoding);
                    Properties.Add(prop);
                }

                // 1st IFD pointer
                int firstifdpointer = (int)conv.ToUInt32(header, ifdoffset + 2 + 12 * fieldcount);
                if (firstifdpointer != 0)
                {
                    ifdqueue.Add(firstifdpointer, IFD.First);
                }
                // Read thumbnail
                if (thumboffset != -1 && thumblength != 0 && Thumbnail == null)
                {
                    if (thumbtype == 0)
                    {
                        using (MemoryStream ts = new MemoryStream(header, tiffoffset + thumboffset, thumblength))
                        {
                            Thumbnail = ImageFile.FromStream(ts);
                        }
                    }
                }
            }
        }