ProcessJpegSegmentData(IEnumerable <IJpegSegmentMetadataReader> readers, JpegSegmentData segmentData)
{
// Pass the appropriate byte arrays to each reader.
return((from reader in readers
from segmentType in reader.GetSegmentTypes()
from directory in reader.ReadJpegSegments(segmentData.GetSegments(segmentType), segmentType)
select directory)
.ToList());
}
public void TestContainsSegment()
{
var segmentData = new JpegSegmentData();
var segmentType = JpegSegmentType.App3;
var segmentBytes = new byte[] { 1, 2, 3 };
Assert.True(!segmentData.ContainsSegment(segmentType));
segmentData.AddSegment(segmentType, segmentBytes);
Assert.True(segmentData.ContainsSegment(segmentType));
}
public void TestAddAndGetSegment()
{
var segmentData = new JpegSegmentData();
var segmentType = JpegSegmentType.App3;
var segmentBytes = new byte[] { 1, 2, 3 };
segmentData.AddSegment(segmentType, segmentBytes);
Assert.Equal(1, segmentData.GetSegmentCount(segmentType));
Assert.Equal(segmentBytes, segmentData.GetSegment(segmentType));
}
public void TestSegmentWithMultipleOccurrences()
{
var segmentData = new JpegSegmentData();
var segmentType = JpegSegmentType.App3;
var segmentBytes1 = new byte[] { 1, 2, 3 };
var segmentBytes2 = new byte[] { 3, 2, 1 };
segmentData.AddSegment(segmentType, segmentBytes1);
segmentData.AddSegment(segmentType, segmentBytes2);
Assert.Equal(2, segmentData.GetSegmentCount(segmentType));
Assert.Equal(segmentBytes1, segmentData.GetSegment(segmentType));
Assert.Equal(segmentBytes2, segmentData.GetSegment(segmentType, occurrence: 1));
}
public void TestAddingMultipleSegments()
{
var segmentData = new JpegSegmentData();
var segmentType1 = JpegSegmentType.App3;
var segmentType2 = JpegSegmentType.App4;
var segmentBytes1 = new byte[] { 1, 2, 3 };
var segmentBytes2 = new byte[] { 3, 2, 1 };
segmentData.AddSegment(segmentType1, segmentBytes1);
segmentData.AddSegment(segmentType2, segmentBytes2);
Assert.Equal(1, segmentData.GetSegmentCount(segmentType1));
Assert.Equal(1, segmentData.GetSegmentCount(segmentType2));
Assert.Equal(segmentBytes1, segmentData.GetSegment(segmentType1));
Assert.Equal(segmentBytes2, segmentData.GetSegment(segmentType2));
}
public void TestRemoveSegment()
{
var segmentData = new JpegSegmentData();
var segmentType = JpegSegmentType.App3;
var segmentBytes1 = new byte[] { 1, 2, 3 };
var segmentBytes2 = new byte[] { 3, 2, 1 };
segmentData.AddSegment(segmentType, segmentBytes1);
segmentData.AddSegment(segmentType, segmentBytes2);
Assert.Equal(2, segmentData.GetSegmentCount(segmentType));
Assert.True(segmentData.ContainsSegment(segmentType));
Assert.Equal(segmentBytes1, segmentData.GetSegment(segmentType));
segmentData.RemoveAllSegments(segmentType);
Assert.True(!segmentData.ContainsSegment(segmentType));
Assert.Equal(0, segmentData.GetSegmentCount(segmentType));
}
private static void SaveSegmentFiles(string jpegFilePath, JpegSegmentData segmentData)
{
foreach (var segmentType in segmentData.GetSegmentTypes())
{
IList<byte[]> segments = segmentData.GetSegments(segmentType).ToList();
if (segments.Count == 0)
continue;
var format = segments.Count > 1 ? "{0}.{1}.{2}" : "{0}.{1}";
for (var i = 0; i < segments.Count; i++)
{
var outputFilePath = string.Format(format, jpegFilePath, segmentType.ToString().ToLower(), i);
Console.Out.WriteLine("Writing: " + outputFilePath);
File.WriteAllBytes(outputFilePath, segments[i]);
}
}
}
ProcessJpegSegmentData(IEnumerable<IJpegSegmentMetadataReader> readers, JpegSegmentData segmentData)
{
// Pass the appropriate byte arrays to each reader.
return (from reader in readers
from segmentType in reader.GetSegmentTypes()
from directory in reader.ReadJpegSegments(segmentData.GetSegments(segmentType), segmentType)
select directory)
.ToList();
}
public static JpegSegmentData ReadSegments([NotNull] SequentialReader reader, [CanBeNull] ICollection<JpegSegmentType> segmentTypes = null)
{
// Must be big-endian
Debug.Assert(reader.IsMotorolaByteOrder);
// first two bytes should be JPEG magic number
var magicNumber = reader.GetUInt16();
if (magicNumber != 0xFFD8)
throw new JpegProcessingException($"JPEG data is expected to begin with 0xFFD8 (ÿØ) not 0x{magicNumber:X4}");
var segmentData = new JpegSegmentData();
do
{
// Find the segment marker. Markers are zero or more 0xFF bytes, followed
// by a 0xFF and then a byte not equal to 0x00 or 0xFF.
var segmentIdentifier = reader.GetByte();
var segmentTypeByte = reader.GetByte();
// Read until we have a 0xFF byte followed by a byte that is not 0xFF or 0x00
while (segmentIdentifier != 0xFF || segmentTypeByte == 0xFF || segmentTypeByte == 0)
{
segmentIdentifier = segmentTypeByte;
segmentTypeByte = reader.GetByte();
}
var segmentType = (JpegSegmentType)segmentTypeByte;
if (segmentType == JpegSegmentType.Sos)
{
// The 'Start-Of-Scan' segment's length doesn't include the image data, instead would
// have to search for the two bytes: 0xFF 0xD9 (EOI).
// It comes last so simply return at this point
return segmentData;
}
if (segmentType == JpegSegmentType.Eoi)
{
// the 'End-Of-Image' segment -- this should never be found in this fashion
return segmentData;
}
// next 2-bytes are <segment-size>: [high-byte] [low-byte]
var segmentLength = (int)reader.GetUInt16();
// segment length includes size bytes, so subtract two
segmentLength -= 2;
if (segmentLength < 0)
throw new JpegProcessingException("JPEG segment size would be less than zero");
// Check whether we are interested in this segment
if (segmentTypes == null || segmentTypes.Contains(segmentType))
{
var segmentBytes = reader.GetBytes(segmentLength);
Debug.Assert(segmentLength == segmentBytes.Length);
segmentData.AddSegment(segmentType, segmentBytes);
}
else
{
// Some of the JPEG is truncated, so just return what data we've already gathered
if (!reader.TrySkip(segmentLength))
{
return segmentData;
}
}
}
while (true);
}
public static JpegSegmentData ReadSegments([NotNull] SequentialReader reader, [CanBeNull] ICollection <JpegSegmentType> segmentTypes = null)
{
// Must be big-endian
Debug.Assert(reader.IsMotorolaByteOrder);
// first two bytes should be JPEG magic number
var magicNumber = reader.GetUInt16();
if (magicNumber != 0xFFD8)
{
throw new JpegProcessingException($"JPEG data is expected to begin with 0xFFD8 (ÿØ) not 0x{magicNumber:X4}");
}
var segmentData = new JpegSegmentData();
do
{
// Find the segment marker. Markers are zero or more 0xFF bytes, followed
// by a 0xFF and then a byte not equal to 0x00 or 0xFF.
var segmentIdentifier = reader.GetByte();
// We must have at least one 0xFF byte
if (segmentIdentifier != 0xFF)
{
throw new JpegProcessingException($"Expected JPEG segment start identifier 0xFF, not 0x{segmentIdentifier:X2}");
}
// Read until we have a non-0xFF byte. This identifies the segment type.
var segmentTypeByte = reader.GetByte();
while (segmentTypeByte == 0xFF)
{
segmentTypeByte = reader.GetByte();
}
if (segmentTypeByte == 0)
{
throw new JpegProcessingException("Expected non-zero byte as part of JPEG marker identifier");
}
var segmentType = (JpegSegmentType)segmentTypeByte;
if (segmentType == JpegSegmentType.Sos)
{
// The 'Start-Of-Scan' segment's length doesn't include the image data, instead would
// have to search for the two bytes: 0xFF 0xD9 (EOI).
// It comes last so simply return at this point
return(segmentData);
}
if (segmentType == JpegSegmentType.Eoi)
{
// the 'End-Of-Image' segment -- this should never be found in this fashion
return(segmentData);
}
// next 2-bytes are <segment-size>: [high-byte] [low-byte]
var segmentLength = (int)reader.GetUInt16();
// segment length includes size bytes, so subtract two
segmentLength -= 2;
if (segmentLength < 0)
{
throw new JpegProcessingException("JPEG segment size would be less than zero");
}
// Check whether we are interested in this segment
if (segmentTypes == null || segmentTypes.Contains(segmentType))
{
var segmentBytes = reader.GetBytes(segmentLength);
Debug.Assert(segmentLength == segmentBytes.Length);
segmentData.AddSegment(segmentType, segmentBytes);
}
else
{
// Some of the JPEG is truncated, so just return what data we've already gathered
if (!reader.TrySkip(segmentLength))
{
return(segmentData);
}
}
}while (true);
}
public void TestRemoveSegmentOccurrence()
{
var segmentData = new JpegSegmentData();
var segmentType = JpegSegmentType.App3;
var segmentBytes1 = new byte[] { 1, 2, 3 };
var segmentBytes2 = new byte[] { 3, 2, 1 };
segmentData.AddSegment(segmentType, segmentBytes1);
segmentData.AddSegment(segmentType, segmentBytes2);
Assert.Equal(2, segmentData.GetSegmentCount(segmentType));
Assert.Equal(segmentBytes1, segmentData.GetSegment(segmentType));
segmentData.RemoveSegmentOccurrence(segmentType, 0);
Assert.Equal(segmentBytes2, segmentData.GetSegment(segmentType));
}
