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Tiff: ccitt compression, fix for issue #2451 #2483

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Merged
merged 3 commits into from
Jun 25, 2023
Merged

Tiff: ccitt compression, fix for issue #2451 #2483

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6c43909
If we read a extension code, read the next 5 bits because some encode…
brianpopow Jun 24, 2023
450279b
Merge branch 'main' into bp/Issue2451
JimBobSquarePants Jun 25, 2023
63aece9
Update src/ImageSharp/Formats/Tiff/Compression/Decompressors/T6BitRea…
JimBobSquarePants Jun 25, 2023
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20 changes: 18 additions & 2 deletions src/ImageSharp/Formats/Tiff/Compression/Decompressors/T6BitReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -125,13 +125,29 @@ public bool ReadNextCodeWord()
if (value == Len7Code0000000.Code)
{
this.Code = Len7Code0000000;
return false;

// We do not support Extensions1D codes, but some encoders (scanner from epson) write a premature EOL code,
// which at this point cannot be distinguished from the marker, because we read the data bit by bit.
// Read the next 5 bit, if its a EOL code return true, indicating its the end of the image.
if (this.ReadValue(5) == 1)
{
return true;
}

throw new NotSupportedException("ccitt extensions 1D codes are not supported.");
}

if (value == Len7Code0000001.Code)
{
this.Code = Len7Code0000001;
return false;

// Same as above, we do not support Extensions2D codes, but it could be a EOL instead.
if (this.ReadValue(5) == 1)
{
return true;
}

throw new NotSupportedException("ccitt extensions 2D codes are not supported.");
}

if (value == Len7Code0000011.Code)
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