C#C
C#•5mo ago
swagrid

✅BinaryReader reads garbage when reading from compressed stream

This is a weird one - I think. So I have a rather complex data type that I write to and load from disk. I'm using a ZipArchive to get some data compression.

Writing basically looks like this:
using var archive = new ZipArchive(someFileStream, ZipArchiveMode.Create, leaveOpen: true);
using var stream = archive.CreateEntry("myentry.txt", CompressionLevel.NoCompression).Open();
using var writer = new BinaryWriter(stream);
// serialize all data using writer

and reading like this:
using var archive = new ZipArchive(someFileStream, ZipArchiveMode.Read, leaveOpen: true);
using var stream = archive.GetEntry("myentry.txt").Open();
using var reader = new BinaryReader(stream);
// deserialize all data using reader


The code above works fine as long as I have NoCompression specified. I can successfully write and then read the file back. However, as soon as I change the compression level to anything else (like Optimal), I get a random error in the middle of reading with reader where it tries to read the length of an array and it reads it as a billion or something (where it should be like 100). I've gone through it with the debugger and all data up to that point is read correctly. I also don't think this is a new code path it runs into the first time. The same code has been called multiple times already before running into the error.

(more details in thread)
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