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Merge pull request #393 from iamcarbon/cq4
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Introduce BufferReader and eliminate a bunch of allocations
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@drewnoakes
drewnoakes authored Feb 4, 2024
2 parents 55808d1 + 1b38f68 commit 1f990bf
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Showing 12 changed files with 293 additions and 187 deletions.
27 changes: 14 additions & 13 deletions MetadataExtractor/Formats/Apple/BplistReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -45,27 +45,28 @@ public static PropertyListResults Parse(byte[] bplist)

Trailer trailer = ReadTrailer();

SequentialByteArrayReader reader = new(bplist, baseIndex: checked((int)(trailer.OffsetTableOffset + trailer.TopObject)));
int offset = checked((int)(trailer.OffsetTableOffset + trailer.TopObject));
var reader = new BufferReader(bplist.AsSpan(offset), isBigEndian: true);

int[] offsets = new int[(int)trailer.NumObjects];

for (long i = 0; i < trailer.NumObjects; i++)
for (int i = 0; i < (int)trailer.NumObjects; i++)
{
if (trailer.OffsetIntSize == 1)
{
offsets[(int)i] = reader.GetByte();
offsets[i] = reader.GetByte();
}
else if (trailer.OffsetIntSize == 2)
{
offsets[(int)i] = reader.GetUInt16();
offsets[i] = reader.GetUInt16();
}
}

List<object> objects = [];

for (int i = 0; i < offsets.Length; i++)
{
reader = new SequentialByteArrayReader(bplist, offsets[i]);
reader = new BufferReader(bplist.AsSpan(offsets[i]), isBigEndian: true);

byte b = reader.GetByte();

Expand All @@ -75,13 +76,13 @@ public static PropertyListResults Parse(byte[] bplist)
object obj = objectFormat switch
{
// dict
0x0D => HandleDict(marker),
0x0D => HandleDict(ref reader, marker),
// string (ASCII)
0x05 => reader.GetString(bytesRequested: marker & 0x0F, Encoding.ASCII),
// data
0x04 => HandleData(marker),
0x04 => HandleData(ref reader, marker),
// int
0x01 => HandleInt(marker),
0x01 => HandleInt(ref reader, marker),
// unknown
_ => throw new NotSupportedException($"Unsupported object format {objectFormat:X2}.")
};
Expand All @@ -93,10 +94,10 @@ public static PropertyListResults Parse(byte[] bplist)

Trailer ReadTrailer()
{
SequentialByteArrayReader reader = new(bplist, bplist.Length - Trailer.SizeBytes);
var reader = new BufferReader(bplist.AsSpan(bplist.Length - Trailer.SizeBytes), isBigEndian: true);

// Skip 5-byte unused values, 1-byte sort version.
reader.Skip(6);
reader.Skip(5 + 1);

return new Trailer
{
Expand All @@ -108,7 +109,7 @@ Trailer ReadTrailer()
};
}

object HandleInt(byte marker)
static object HandleInt(ref BufferReader reader, byte marker)
{
return marker switch
{
Expand All @@ -120,7 +121,7 @@ object HandleInt(byte marker)
};
}

Dictionary<byte, byte> HandleDict(byte count)
static Dictionary<byte, byte> HandleDict(ref BufferReader reader, byte count)
{
var keyRefs = ArrayPool<byte>.Shared.Rent(count);

Expand All @@ -141,7 +142,7 @@ Dictionary<byte, byte> HandleDict(byte count)
return map;
}

object HandleData(byte marker)
object HandleData(ref BufferReader reader, byte marker)
{
int byteCount = marker;

Expand Down
145 changes: 42 additions & 103 deletions MetadataExtractor/Formats/Exif/makernotes/OlympusCameraSettingsMakernoteDescriptor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -160,30 +160,16 @@ public sealed class OlympusCameraSettingsMakernoteDescriptor(OlympusCameraSettin
return null;

var sb = new StringBuilder();
switch (values[0])
sb.Append(values[0] switch
{
case 0:
sb.Append("Single AF");
break;
case 1:
sb.Append("Sequential shooting AF");
break;
case 2:
sb.Append("Continuous AF");
break;
case 3:
sb.Append("Multi AF");
break;
case 4:
sb.Append("Face detect");
break;
case 10:
sb.Append("MF");
break;
default:
sb.Append("Unknown (" + values[0] + ")");
break;
}
0 => "Single AF",
1 => "Sequential shooting AF",
2 => "Continuous AF",
3 => "Multi AF",
4 => "Face detect",
10 => "MF",
_ => $"Unknown ({values[0]})"
});

if (values.Length > 1)
{
Expand Down Expand Up @@ -231,18 +217,12 @@ public sealed class OlympusCameraSettingsMakernoteDescriptor(OlympusCameraSettin

var sb = new StringBuilder();

switch (values[0])
sb.Append(values[0] switch
{
case 0:
sb.Append("AF not used");
break;
case 1:
sb.Append("AF used");
break;
default:
sb.Append("Unknown (" + values[0] + ")");
break;
}
0 => "AF not used",
1 => "AF used",
_ => $"Unknown ({values[0]})"
});

if (values.Length > 1)
sb.Append("; " + values[1]);
Expand Down Expand Up @@ -385,24 +365,14 @@ public sealed class OlympusCameraSettingsMakernoteDescriptor(OlympusCameraSettin

var sb = new StringBuilder();

switch (values[0])
sb.Append(values[0] switch
{
case 0:
sb.Append("Off");
break;
case 3:
sb.Append("TTL");
break;
case 4:
sb.Append("Auto");
break;
case 5:
sb.Append("Manual");
break;
default:
sb.Append("Unknown (" + values[0] + ")");
break;
}
0 => "Off",
3 => "TTL",
4 => "Auto",
5 => "Manual",
_ => $"Unknown ({values[0]})"
});

for (var i = 1; i < values.Length; i++)
sb.Append("; ").Append(values[i]);
Expand Down Expand Up @@ -692,33 +662,17 @@ public sealed class OlympusCameraSettingsMakernoteDescriptor(OlympusCameraSettin
return null;

var sb = new StringBuilder();
switch (values[0])
sb.Append(values[0] switch
{
case 1:
sb.Append("Vivid");
break;
case 2:
sb.Append("Natural");
break;
case 3:
sb.Append("Muted");
break;
case 4:
sb.Append("Portrait");
break;
case 5:
sb.Append("i-Enhance");
break;
case 256:
sb.Append("Monotone");
break;
case 512:
sb.Append("Sepia");
break;
default:
sb.Append("Unknown (").Append(values[0]).Append(')');
break;
}
1 => "Vivid",
2 => "Natural",
3 => "Muted",
4 => "Portrait",
5 => "i-Enhance",
256 => "Monotone",
512 => "Sepia",
_ => $"Unknown ({values[0]})"
});

if (values.Length > 1)
sb.Append("; ").Append(values[1]);
Expand Down Expand Up @@ -822,33 +776,18 @@ public sealed class OlympusCameraSettingsMakernoteDescriptor(OlympusCameraSettin
sb.Append("Partial Color " + values[i] + "; ");
else if (i == 4)
{
switch (values[i])
sb.Append(values[i] switch
{
case 0x0000:
sb.Append("No Effect");
break;
case 0x8010:
sb.Append("Star Light");
break;
case 0x8020:
sb.Append("Pin Hole");
break;
case 0x8030:
sb.Append("Frame");
break;
case 0x8040:
sb.Append("Soft Focus");
break;
case 0x8050:
sb.Append("White Edge");
break;
case 0x8060:
sb.Append("B&W");
break;
default:
sb.Append("Unknown (").Append(values[i]).Append(')');
break;
}
0x0000 => "No Effect",
0x8010 => "Star Light",
0x8020 => "Pin Hole",
0x8030 => "Frame",
0x8040 => "Soft Focus",
0x8050 => "White Edge",
0x8060 => "B&W",
_ => $"Unknown ({values[i]})"
});

sb.Append("; ");
}
else if (i == 6)
Expand Down
4 changes: 2 additions & 2 deletions MetadataExtractor/Formats/Exif/makernotes/OlympusMakernoteDirectory.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -448,9 +448,9 @@ public override void Set(int tagType, object value)
base.Set(tagType, value);
}

private void ProcessCameraSettings(byte[] bytes)
private void ProcessCameraSettings(ReadOnlySpan<byte> bytes)
{
var reader = new SequentialByteArrayReader(bytes);
var reader = new BufferReader(bytes, isBigEndian: true);
var count = bytes.Length / 4;

for (var i = 0; i < count; i++)
Expand Down
5 changes: 3 additions & 2 deletions MetadataExtractor/Formats/Flir/FlirReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -163,8 +163,9 @@ public IEnumerable<Directory> Extract(IndexedReader reader)
directory.Set(TagRawValueMedian, reader2.GetUInt16(TagRawValueMedian));
directory.Set(TagRawValueRange, reader2.GetUInt16(TagRawValueRange));

var dateTimeBytes = reader2.GetBytes(TagDateTimeOriginal, 10);
var dateTimeReader = new SequentialByteArrayReader(dateTimeBytes, isMotorolaByteOrder: false);
Span<byte> dateTimeBytes = stackalloc byte[10];
reader2.GetBytes(TagDateTimeOriginal, dateTimeBytes);
var dateTimeReader = new BufferReader(dateTimeBytes, isBigEndian: false);
var tm = dateTimeReader.GetUInt32();
var ss = dateTimeReader.GetUInt32() & 0xffff;
var tz = dateTimeReader.GetInt16();
Expand Down
60 changes: 35 additions & 25 deletions MetadataExtractor/Formats/Jpeg/JpegReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -29,35 +29,45 @@ public JpegDirectory Extract(JpegSegment segment)
// The value of TagCompressionType is determined by the segment type found
directory.Set(JpegDirectory.TagCompressionType, (int)segment.Type - (int)JpegSegmentType.Sof0);

SequentialReader reader = new SequentialByteArrayReader(segment.Bytes);
const int JpegHeaderSize = 1 + 2 + 2 + 1;

try
if (segment.Span.Length < JpegHeaderSize)
{
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 < componentCount; i++)
{
var componentId = reader.GetByte();
var samplingFactorByte = reader.GetByte();
var quantizationTableNumber = reader.GetByte();
var component = new JpegComponent(componentId, samplingFactorByte, quantizationTableNumber);
directory.Set(JpegDirectory.TagComponentData1 + i, component);
}
directory.AddError("Insufficient bytes for JPEG segment header.");

return directory;
}
catch (IOException ex)

var reader = new BufferReader(segment.Span, isBigEndian: true);

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);

const int JpegComponentSize = 1 + 1 + 1;

if (reader.Available < componentCount * JpegComponentSize)
{
directory.AddError("Insufficient bytes for JPEG the requested number of JPEG components.");
return directory;
}

// 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 < componentCount; i++)
{
directory.AddError(ex.Message);
var componentId = reader.GetByte();
var samplingFactorByte = reader.GetByte();
var quantizationTableNumber = reader.GetByte();
var component = new JpegComponent(componentId, samplingFactorByte, quantizationTableNumber);
directory.Set(JpegDirectory.TagComponentData1 + i, component);
}

return directory;
Expand Down
7 changes: 5 additions & 2 deletions MetadataExtractor/Formats/Photoshop/PhotoshopReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -53,12 +53,15 @@ public IReadOnlyList<Directory> Extract(SequentialReader reader, int length)
// http://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#50577409_pgfId-1037504
var pos = 0;
int clippingPathCount = 0;

Span<byte> signature = stackalloc byte[4];

while (pos < length)
{
try
{
// 4 bytes for the signature ("8BIM", "PHUT", etc.)
var signature = reader.GetString(4, Encoding.UTF8);
reader.GetBytes(signature);
pos += 4;

// 2 bytes for the resource identifier (tag type).
Expand Down Expand Up @@ -106,7 +109,7 @@ public IReadOnlyList<Directory> Extract(SequentialReader reader, int length)
}

// Skip any unsupported IRBs
if (signature != "8BIM")
if (!signature.SequenceEqual("8BIM"u8))
continue;

switch (tagType)
Expand Down
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