ReadJpegSegments(IEnumerable <byte[]> segments, JpegSegmentType segmentType)
{
// ICC data can be spread across multiple JPEG segments.
// Skip any segments that do not contain the required preamble
var iccSegments = segments.Where(segment => segment.Length > SegmentHeaderLength && IsSubarrayEqualTo(segment, 0, _jpegSegmentPreambleBytes)).ToList();
if (iccSegments.Count == 0)
{
return(new Directory[0]);
}
byte[] buffer;
if (iccSegments.Count == 1)
{
buffer = new byte[iccSegments[0].Length - SegmentHeaderLength];
Array.Copy(iccSegments[0], SegmentHeaderLength, buffer, 0, iccSegments[0].Length - SegmentHeaderLength);
}
else
{
// Concatenate all buffers
var totalLength = iccSegments.Sum(s => s.Length - SegmentHeaderLength);
buffer = new byte[totalLength];
for (int i = 0, pos = 0; i < iccSegments.Count; i++)
{
var segment = iccSegments[i];
Array.Copy(segment, SegmentHeaderLength, buffer, pos, segment.Length - SegmentHeaderLength);
pos += segment.Length - SegmentHeaderLength;
}
}
return(new[] { Extract(new ByteArrayReader(buffer)) });
}
/// <exception cref="System.IO.IOException"/>
/// <exception cref="Com.Drew.Imaging.Jpeg.JpegProcessingException"/>
public static void Main(string[] args)
{
if (args.Length < 1)
{
PrintUsage();
System.Environment.Exit(1);
}
string filePath = args[0];
if (!new FilePath(filePath).Exists())
{
System.Console.Error.Println("File does not exist");
PrintUsage();
System.Environment.Exit(1);
}
ICollection <JpegSegmentType> segmentTypes = new HashSet <JpegSegmentType>();
for (int i = 1; i < args.Length; i++)
{
JpegSegmentType segmentType = JpegSegmentType.ValueOf(args[i].ToUpper());
if (!segmentType.canContainMetadata)
{
System.Console.Error.Printf("WARNING: Segment type %s cannot contain metadata so it may not be necessary to extract it%n", segmentType);
}
segmentTypes.Add(segmentType);
}
if (segmentTypes.Count == 0)
{
// If none specified, use all that could reasonably contain metadata
Sharpen.Collections.AddAll(segmentTypes, JpegSegmentType.canContainMetadataTypes);
}
JpegSegmentData segmentData = JpegSegmentReader.ReadSegments(new FilePath(filePath), segmentTypes.AsIterable());
SaveSegmentFiles(filePath, segmentData);
}
/// <summary>
/// Split data array to segments of length at most <paramref name="maxSegmentSize"/> bytes
/// </summary>
/// <param name="data">Data to split</param>
/// <param name="type">Type of each JPEG segment</param>
/// <param name="header">
/// Header of each JPEG segment. All characters have to be ASCII.
/// </param>
/// <param name="maxSegmentSize">
/// Maximal size of the JPEG segment (excluding the 2 size bytes)
/// </param>
/// <returns>JPEG segments enumerator</returns>
public static IEnumerable <JpegSegment> SplitSegmentData(
byte[] data,
JpegSegmentType type,
string header,
long maxSegmentSize = MaxSegmentSize)
{
if (header.Length >= maxSegmentSize)
{
throw new ArgumentException(
"Header must fit in the JPEG segment with some data.");
}
long dataOffset = 0;
while (dataOffset < data.Length)
{
long bufferSize = Math.Min(
data.Length - dataOffset,
maxSegmentSize - header.Length);
var buffer = new byte[bufferSize + header.Length];
// copy header
for (int i = 0; i < header.Length; ++i)
{
buffer[i] = (byte)header[i];
}
// copy part of the data
Array.Copy(data, dataOffset, buffer, header.Length, bufferSize);
dataOffset += bufferSize;
yield return(new JpegSegment(type, buffer, 0));
}
}
ReadJpegSegments(IEnumerable<byte[]> segments, JpegSegmentType segmentType)
{
var preambleLength = JpegSegmentPreamble.Length;
return segments
.Where(segment => segment.Length >= preambleLength + 1 && JpegSegmentPreamble == Encoding.UTF8.GetString(segment, 0, preambleLength))
.SelectMany(segment => Extract(new SequentialByteArrayReader(segment, preambleLength + 1), segment.Length - preambleLength - 1))
.ToList();
}
public JpegSegment(JpegSegmentType type, int length, int padding, long offset, string preamble)
{
Type = type;
Length = length;
Padding = padding;
Offset = offset;
Preamble = preamble;
}
ReadJpegSegments(IEnumerable<byte[]> segments, JpegSegmentType segmentType)
{
Debug.Assert(segmentType == JpegSegmentType.App1);
return segments
.Where(segment => segment.Length >= JpegSegmentPreamble.Length && Encoding.UTF8.GetString(segment, 0, JpegSegmentPreamble.Length) == JpegSegmentPreamble)
.SelectMany(segment => Extract(new ByteArrayReader(segment), JpegSegmentPreamble.Length))
.ToList();
}
ReadJpegSegments(IEnumerable <byte[]> segments, JpegSegmentType segmentType)
{
var preambleLength = JpegSegmentPreamble.Length;
return(segments
.Where(segment => segment.Length >= preambleLength + 1 && JpegSegmentPreamble == Encoding.UTF8.GetString(segment, 0, preambleLength))
.SelectMany(segment => Extract(new SequentialByteArrayReader(segment, preambleLength + 1), segment.Length - preambleLength - 1))
.ToList());
}
/// <summary>Removes a specified instance of a segment's data from the collection.</summary>
/// <remarks>
/// Removes a specified instance of a segment's data from the collection. Use this method when more than one
/// occurrence of segment data exists for a given type exists.
/// </remarks>
/// <param name="segmentType">identifies the required segment</param>
/// <param name="occurrence">the zero-based index of the segment occurrence to remove.</param>
public void RemoveSegmentOccurrence(JpegSegmentType segmentType, int occurrence)
{
IList <byte[]> segmentList;
if (_segmentDataMap.TryGetValue(segmentType, out segmentList))
{
segmentList.RemoveAt(occurrence);
}
}
ReadJpegSegments(IEnumerable <byte[]> segments, JpegSegmentType segmentType)
{
Debug.Assert(segmentType == JpegSegmentType.App1);
return(segments
.Where(segment => segment.Length >= JpegSegmentPreamble.Length && Encoding.UTF8.GetString(segment, 0, JpegSegmentPreamble.Length) == JpegSegmentPreamble)
.SelectMany(segment => Extract(new ByteArrayReader(segment), JpegSegmentPreamble.Length))
.ToList());
}
ReadJpegSegments(IEnumerable <byte[]> segments, JpegSegmentType segmentType)
{
return(segments
.Where(segment => segment.Length == 12 && Preamble.Equals(Encoding.ASCII.GetString(segment, 0, Preamble.Length), StringComparison.OrdinalIgnoreCase))
.Select(bytes => Extract(new SequentialByteArrayReader(bytes)))
#if NET35
.Cast <Directory>()
#endif
.ToList());
}
ReadJpegSegments(IEnumerable<byte[]> segments, JpegSegmentType segmentType)
{
return segments
.Where(segment => segment.Length == 12 && Preamble.Equals(Encoding.ASCII.GetString(segment, 0, Preamble.Length), StringComparison.OrdinalIgnoreCase))
.Select(bytes => Extract(new SequentialByteArrayReader(bytes)))
#if NET35
.Cast<Directory>()
#endif
.ToList();
}
ReadJpegSegments(IEnumerable<byte[]> segments, JpegSegmentType segmentType)
{
// Ensure data starts with the IPTC marker byte
return segments
.Where(segment => segment.Length != 0 && segment[0] == IptcMarkerByte)
.Select(segment => Extract(new SequentialByteArrayReader(segment), segment.Length))
#if NET35
.Cast<Directory>()
#endif
.ToList();
}
private IList <byte[]> GetOrCreateSegmentList(JpegSegmentType segmentType)
{
IList <byte[]> segmentList;
if (!_segmentDataMap.TryGetValue(segmentType, out segmentList))
{
segmentList = new List <byte[]>();
_segmentDataMap[segmentType] = segmentList;
}
return(segmentList);
}
ReadJpegSegments(IEnumerable <byte[]> segments, JpegSegmentType segmentType)
{
// Ensure data starts with the IPTC marker byte
return(segments
.Where(segment => segment.Length != 0 && segment[0] == IptcMarkerByte)
.Select(segment => Extract(new SequentialByteArrayReader(segment), segment.Length))
#if NET35
.Cast <Directory>()
#endif
.ToList());
}
ReadJpegSegments(IEnumerable <byte[]> segments, JpegSegmentType segmentType)
{
// Skip segments not starting with the required header
return(segments
.Where(segment => segment.Length >= Preamble.Length && Preamble == Encoding.ASCII.GetString(segment, 0, Preamble.Length))
.Select(segment => Extract(new SequentialByteArrayReader(segment, Preamble.Length)))
#if NET35
.Cast <Directory>()
#endif
.ToList());
}
ReadJpegSegments(IEnumerable<byte[]> segments, JpegSegmentType segmentType)
{
// Skip segments not starting with the required header
return segments
.Where(segment => segment.Length >= Preamble.Length && Preamble == Encoding.ASCII.GetString(segment, 0, Preamble.Length))
.Select(segment => Extract(new SequentialByteArrayReader(segment, Preamble.Length)))
#if NET35
.Cast<Directory>()
#endif
.ToList();
}
ReadJpegSegments(IEnumerable <byte[]> segments, JpegSegmentType segmentType)
{
Debug.Assert(segmentType == JpegSegmentType.Com);
// TODO store bytes in the directory to allow different encodings when decoding
// The entire contents of the segment are the comment
return(segments.Select(segment => new JpegCommentDirectory(Encoding.UTF8.GetString(segment)))
#if NET35
.Cast <Directory>()
#endif
.ToList());
}
/// <summary>Gets whether this JPEG segment type might contain metadata.</summary>
/// <remarks>Used to exclude large image-data-only segment from certain types of processing.</remarks>
public static bool CanContainMetadata(this JpegSegmentType type)
{
switch (type)
{
case JpegSegmentType.Soi:
case JpegSegmentType.Dqt:
case JpegSegmentType.Dht:
return(false);
default:
return(true);
}
}
ReadJpegSegments(IEnumerable<byte[]> segments, JpegSegmentType segmentType)
{
Debug.Assert(segmentType == JpegSegmentType.Com);
// TODO store bytes in the directory to allow different encodings when decoding
// The entire contents of the segment are the comment
return segments.Select(segment => new JpegCommentDirectory(Encoding.UTF8.GetString(segment)))
#if NET35
.Cast<Directory>()
#endif
.ToList();
}
/// <summary>
/// Check segment type and header.
/// </summary>
/// <param name="segment">JPEG segment</param>
/// <param name="type">Expected type</param>
/// <param name="header">Expected header</param>
/// <returns>true iff the segment has given type and header</returns>
public static bool MatchSegment(JpegSegment segment, JpegSegmentType type, string header)
{
if (segment.Type != type || segment.Bytes.Length < header.Length)
{
return(false);
}
for (int i = 0; i < header.Length; ++i)
{
if ((char)segment.Bytes[i] != header[i])
{
return(false);
}
}
return(true);
}
ReadJpegSegments(IEnumerable <byte[]> segments, JpegSegmentType segmentType)
{
var directories = new List <Directory>();
foreach (var segmentBytes in segments)
{
// XMP in a JPEG file has an identifying preamble which is not valid XML
var preambleLength = XmpJpegPreamble.Length;
if (segmentBytes.Length >= preambleLength && XmpJpegPreamble.Equals(Encoding.UTF8.GetString(segmentBytes, 0, preambleLength), StringComparison.OrdinalIgnoreCase))
{
var xmlBytes = new byte[segmentBytes.Length - preambleLength];
Array.Copy(segmentBytes, preambleLength, xmlBytes, 0, xmlBytes.Length);
directories.Add(Extract(xmlBytes));
}
}
return(directories);
}
ReadJpegSegments(IEnumerable<byte[]> segments, JpegSegmentType segmentType)
{
var directories = new List<Directory>();
foreach (var segmentBytes in segments)
{
// XMP in a JPEG file has an identifying preamble which is not valid XML
var preambleLength = XmpJpegPreamble.Length;
if (segmentBytes.Length >= preambleLength && XmpJpegPreamble.Equals(Encoding.UTF8.GetString(segmentBytes, 0, preambleLength), StringComparison.OrdinalIgnoreCase))
{
var xmlBytes = new byte[segmentBytes.Length - preambleLength];
Array.Copy(segmentBytes, preambleLength, xmlBytes, 0, xmlBytes.Length);
directories.Add(Extract(xmlBytes));
}
}
return directories;
}
/// <summary>Gets whether this JPEG segment type's marker is followed by a length indicator.</summary>
public static bool ContainsPayload(this JpegSegmentType type)
{
// ReSharper disable once SwitchStatementMissingSomeCases
switch (type)
{
case JpegSegmentType.Soi:
case JpegSegmentType.Eoi:
case JpegSegmentType.Rst0:
case JpegSegmentType.Rst1:
case JpegSegmentType.Rst2:
case JpegSegmentType.Rst3:
case JpegSegmentType.Rst4:
case JpegSegmentType.Rst5:
case JpegSegmentType.Rst6:
case JpegSegmentType.Rst7:
return(false);
default:
return(true);
}
}
/// <summary>
/// Copy segment data from multiple segments without header to a single array.
/// </summary>
/// <param name="segments">All segments</param>
/// <param name="type">Type of segments to copy</param>
/// <param name="header">Header of the segments to copy (first bytes, ASCII characters only)</param>
/// <returns></returns>
public static byte[] JoinSegmentData(
IEnumerable <JpegSegment> segments,
JpegSegmentType type,
string header)
{
// compute the exact size
long size = 0;
foreach (var segment in segments)
{
if (MatchSegment(segment, type, header))
{
size += segment.Bytes.Length - header.Length;
}
}
// copy segments
var buffer = new byte[size];
long bufferOffset = 0;
foreach (var segment in segments)
{
if (MatchSegment(segment, type, header))
{
var bytesToCopyCount = segment.Bytes.Length - header.Length;
Array.Copy(
segment.Bytes,
header.Length,
buffer,
bufferOffset,
bytesToCopyCount);
bufferOffset += bytesToCopyCount;
}
}
return(buffer);
}
/// <summary>Reads JPEG SOF values and returns them in a <see cref="JpegDirectory"/>.</summary>
public JpegDirectory Extract(byte[] segmentBytes, JpegSegmentType segmentType)
{
var directory = new JpegDirectory();
// The value of TagCompressionType is determined by the segment type found
directory.Set(JpegDirectory.TagCompressionType, (int)segmentType - (int)JpegSegmentType.Sof0);
SequentialReader reader = new SequentialByteArrayReader(segmentBytes);
try
{
directory.Set(JpegDirectory.TagDataPrecision, reader.GetByte());
directory.Set(JpegDirectory.TagImageHeight, reader.GetUInt16());
directory.Set(JpegDirectory.TagImageWidth, reader.GetUInt16());
var componentCount = reader.GetByte();
directory.Set(JpegDirectory.TagNumberOfComponents, componentCount);
// for each component, there are three bytes of data:
// 1 - Component ID: 1 = Y, 2 = Cb, 3 = Cr, 4 = I, 5 = Q
// 2 - Sampling factors: bit 0-3 vertical, 4-7 horizontal
// 3 - Quantization table number
for (var i = 0; i < (int)componentCount; i++)
{
int componentId = reader.GetByte();
int samplingFactorByte = reader.GetByte();
int quantizationTableNumber = reader.GetByte();
var component = new JpegComponent(componentId, samplingFactorByte, quantizationTableNumber);
directory.Set(JpegDirectory.TagComponentData1 + i, component);
}
}
catch (IOException ex)
{
directory.AddError(ex.Message);
}
return(directory);
}
/// <summary>Reads JPEG SOF values and returns them in a <see cref="JpegDirectory"/>.</summary>
public JpegDirectory Extract(byte[] segmentBytes, JpegSegmentType segmentType)
{
var directory = new JpegDirectory();
// The value of TagCompressionType is determined by the segment type found
directory.Set(JpegDirectory.TagCompressionType, (int)segmentType - (int)JpegSegmentType.Sof0);
SequentialReader reader = new SequentialByteArrayReader(segmentBytes);
try
{
directory.Set(JpegDirectory.TagDataPrecision, reader.GetByte());
directory.Set(JpegDirectory.TagImageHeight, reader.GetUInt16());
directory.Set(JpegDirectory.TagImageWidth, reader.GetUInt16());
var componentCount = reader.GetByte();
directory.Set(JpegDirectory.TagNumberOfComponents, componentCount);
// for each component, there are three bytes of data:
// 1 - Component ID: 1 = Y, 2 = Cb, 3 = Cr, 4 = I, 5 = Q
// 2 - Sampling factors: bit 0-3 vertical, 4-7 horizontal
// 3 - Quantization table number
for (var i = 0; i < (int)componentCount; i++)
{
int componentId = reader.GetByte();
int samplingFactorByte = reader.GetByte();
int quantizationTableNumber = reader.GetByte();
var component = new JpegComponent(componentId, samplingFactorByte, quantizationTableNumber);
directory.Set(JpegDirectory.TagComponentData1 + i, component);
}
}
catch (IOException ex)
{
directory.AddError(ex.Message);
}
return directory;
}
public static IList <Directory> ProcessSegmentBytes(string filePath, JpegSegmentType type)
{
var segment = new JpegSegment(type, TestDataUtil.GetBytes(filePath), 0);
return(new ExifReader().ReadJpegSegments(new[] { segment }).ToList());
}
public virtual void Extract(sbyte[] segmentBytes, Com.Drew.Metadata.Metadata metadata, JpegSegmentType segmentType)
{
JpegCommentDirectory directory = metadata.GetOrCreateDirectory <JpegCommentDirectory>();
// The entire contents of the directory are the comment
directory.SetString(JpegCommentDirectory.TagComment, Sharpen.Runtime.GetStringForBytes(segmentBytes));
}
public virtual bool CanProcess(sbyte[] segmentBytes, JpegSegmentType segmentType)
{
// The entire contents of the byte[] is the comment. There's nothing here to discriminate upon.
return(true);
}
/// <summary>Removes all segments from the collection having the specified type.</summary>
/// <param name="segmentType">identifies the required segment</param>
public void RemoveAllSegments(JpegSegmentType segmentType)
{
_segmentDataMap.Remove(segmentType);
}
public virtual void ReadJpegSegments([NotNull] Iterable <sbyte[]> segments, [NotNull] Com.Drew.Metadata.Metadata metadata, [NotNull] JpegSegmentType segmentType)
{
foreach (sbyte[] segmentBytes in segments)
{
// Ensure data starts with the IPTC marker byte
if (segmentBytes.Length != 0 && segmentBytes[0] == unchecked ((int)(0x1c)))
{
Extract(new SequentialByteArrayReader(segmentBytes), metadata, segmentBytes.Length);
}
}
}
public JpegSegment(JpegSegmentType type, byte[] bytes, long offset)
{
Type = type;
Bytes = bytes;
Offset = offset;
}
private IList<byte[]> GetSegmentList(JpegSegmentType segmentType)
{
IList<byte[]> list;
return _segmentDataMap.TryGetValue(segmentType, out list) ? list : null;
}
public virtual bool CanProcess(sbyte[] segmentBytes, JpegSegmentType segmentType)
{
return(segmentBytes.Length > 12 && "Photoshop 3.0".Equals(Sharpen.Runtime.GetStringForBytes(segmentBytes, 0, 13)));
}
public virtual void Extract(sbyte[] segmentBytes, Com.Drew.Metadata.Metadata metadata, JpegSegmentType segmentType)
{
Extract(new SequentialByteArrayReader(segmentBytes), metadata);
}
/// <summary>Adds segment bytes to the collection.</summary>
/// <param name="segmentType">the type of the segment being added</param>
/// <param name="segmentBytes">the byte array holding data for the segment being added</param>
public void AddSegment(JpegSegmentType segmentType, [NotNull] byte[] segmentBytes)
{
GetOrCreateSegmentList(segmentType).Add(segmentBytes);
}
public byte[] GetSegment(JpegSegmentType segmentType, int occurrence = 0)
{
var segmentList = GetSegmentList(segmentType);
return segmentList != null && segmentList.Count > occurrence ? segmentList[occurrence] : null;
}
public IEnumerable<byte[]> GetSegments(JpegSegmentType segmentType) => GetSegmentList(segmentType) ?? Enumerable.Empty<byte[]>();
public static T ProcessSegmentBytes <T>(string filePath, JpegSegmentType type) where T : Directory
{
return(ProcessSegmentBytes(filePath, type).OfType <T>().First());
}
/// <summary>Determines whether data is present for a given segment type.</summary>
/// <param name="segmentType">identifies the required segment</param>
/// <returns>true if data exists, otherwise false</returns>
public bool ContainsSegment(JpegSegmentType segmentType)
{
return _segmentDataMap.ContainsKey(segmentType);
}
public virtual bool CanProcess(sbyte[] segmentBytes, JpegSegmentType segmentType)
{
return(segmentBytes.Length == 12 && Sharpen.Runtime.EqualsIgnoreCase("Adobe", Sharpen.Runtime.GetStringForBytes(segmentBytes, 0, 5)));
}
/// <summary>Removes a specified instance of a segment's data from the collection.</summary>
/// <remarks>
/// Removes a specified instance of a segment's data from the collection. Use this method when more than one
/// occurrence of segment data exists for a given type exists.
/// </remarks>
/// <param name="segmentType">identifies the required segment</param>
/// <param name="occurrence">the zero-based index of the segment occurrence to remove.</param>
public void RemoveSegmentOccurrence(JpegSegmentType segmentType, int occurrence)
{
IList<byte[]> segmentList;
if (_segmentDataMap.TryGetValue(segmentType, out segmentList))
{
segmentList.RemoveAt(occurrence);
}
}
private IList<byte[]> GetOrCreateSegmentList(JpegSegmentType segmentType)
{
IList<byte[]> segmentList;
if (!_segmentDataMap.TryGetValue(segmentType, out segmentList))
{
segmentList = new List<byte[]>();
_segmentDataMap[segmentType] = segmentList;
}
return segmentList;
}
/// <summary>Gets whether this JPEG segment is intended to hold application specific data.</summary> public static bool IsApplicationSpecific(this JpegSegmentType type) => type >= JpegSegmentType.App0 && type <= JpegSegmentType.AppF;
public IReadOnlyList<Directory> ReadJpegSegments(IEnumerable<byte[]> segments, JpegSegmentType segmentType)
=> segments.Select(segmentBytes => Extract(segmentBytes, segmentType)).ToList();
/// <summary>Returns the count of segment data byte arrays stored for a given segment type.</summary>
/// <param name="segmentType">identifies the required segment</param>
/// <returns>the segment count (zero if no segments exist).</returns>
public int GetSegmentCount(JpegSegmentType segmentType)
{
return GetSegmentList(segmentType)?.Count ?? 0;
}
public virtual void ReadJpegSegments([NotNull] Iterable <sbyte[]> segments, [NotNull] Com.Drew.Metadata.Metadata metadata, [NotNull] JpegSegmentType segmentType)
{
System.Diagnostics.Debug.Assert((segmentType == JpegSegmentType.App1));
foreach (sbyte[] segmentBytes in segments)
{
// Filter any segments containing unexpected preambles
if (segmentBytes.Length < JpegSegmentPreamble.Length || !Sharpen.Runtime.GetStringForBytes(segmentBytes, 0, JpegSegmentPreamble.Length).Equals(JpegSegmentPreamble))
{
continue;
}
Extract(new ByteArrayReader(segmentBytes), metadata, JpegSegmentPreamble.Length);
}
}
/// <summary>Version specifically for dealing with XMP found in JPEG segments.</summary>
/// <remarks>
/// Version specifically for dealing with XMP found in JPEG segments. This form of XMP has a peculiar preamble, which
/// must be removed before parsing the XML.
/// </remarks>
/// <param name="segments">The byte array from which the metadata should be extracted.</param>
/// <param name="metadata">
/// The
/// <see cref="Com.Drew.Metadata.Metadata"/>
/// object into which extracted values should be merged.
/// </param>
/// <param name="segmentType">
/// The
/// <see cref="Com.Drew.Imaging.Jpeg.JpegSegmentType"/>
/// being read.
/// </param>
public virtual void ReadJpegSegments([NotNull] Iterable <sbyte[]> segments, [NotNull] Com.Drew.Metadata.Metadata metadata, [NotNull] JpegSegmentType segmentType)
{
foreach (sbyte[] segmentBytes in segments)
{
// XMP in a JPEG file has an identifying preamble which is not valid XML
int preambleLength = XmpJpegPreamble.Length;
if (segmentBytes.Length < preambleLength || !Sharpen.Runtime.EqualsIgnoreCase(XmpJpegPreamble, Sharpen.Runtime.GetStringForBytes(segmentBytes, 0, preambleLength)))
{
continue;
}
sbyte[] xmlBytes = new sbyte[segmentBytes.Length - preambleLength];
System.Array.Copy(segmentBytes, preambleLength, xmlBytes, 0, xmlBytes.Length);
Extract(xmlBytes, metadata);
}
}