C# library can enter infinite loop on decompression.

[AlexC-CCL]

Hi,

I happened upon an odd bug when attempting to decompress data which was not a valid brotli stream using the C# library which caused my application to hang. I tracked the bug to this line:

brotli/csharp/org/brotli/dec/BitReader.cs

Line 257 in d74b0a4

if (len == -1)

The Read method will never return -1, it returns 0 on EoF (I think this is just a translation error from Java, this same issue is noted here:

brotli/csharp/org/brotli/dec/BitReader.cs

Line 79 in d74b0a4

// EOF is -1 in Java, but 0 in C#.

but didn't get changed for the other call) - if EoF is hit early in CopyBytes, an infinite loop is entered with the Read method returning 0 over and over and never triggering the exception as it should.

The fix should just be to change -1 to 0 - this correctly triggered the BrotliRuntimeException in my code.

[eustas]

This seems to be fixed in Java code; C# transpiled code needs to be refreshed...

[eustas]

Going soon to change transpiler from sharpen to one used for other languages (go/js/ts/kt). In the meanwhile will add .csproj files and build/test CI workflows.