Background and motivation
.NET 11 introduced the streamless, non-allocating decoders DeflateDecoder, ZLibDecoder, and GZipDecoder. Each holds a native inflate stream and exposes an instance Decompress(...) method plus a static TryDecompress(...) helper.
Once a decoder finishes a stream, the instance latches an internal _finished flag. Every subsequent Decompress call then returns OperationStatus.Done with bytesConsumed == 0 and bytesWritten == 0 , silently doing nothing. This makes the instance effectively one-shot.
This API addresses the reusability limitation reported in #129090.
var decoder = new ZLibDecoder();
decoder.Decompress(streamA, dest, out _, out _); // works
decoder.Decompress(streamB, dest, out _, out _); // silently returns Done, 0/0
Users who want to decode many independent payloads must therefore create and dispose a new decoder for each one, defeating the purpose of the reusable, allocation-conscious instance API (the static TryDecompresy already does create/dispose per call).
API Proposal
namespace System.IO.Compression
{
public sealed partial class DeflateDecoder : System.IDisposable
{
public bool IsFinished { get; }
public void Reset();
}
public sealed partial class ZLibDecoder : System.IDisposable
{
public bool IsFinished { get; }
public void Reset();
}
public sealed partial class GZipDecoder : System.IDisposable
{
public bool IsFinished { get; }
public void Reset();
}
}API Usage
using var decoder = new ZLibDecoder();
foreach (ReadOnlyMemory<byte> payload in payloads)
{
OperationStatus status = decoder.Decompress(payload.Span, destination, out int consumed, out int written);
// ... use destination[..written] ...
if (decoder.IsFinished)
{
decoder.Reset(); // ready for the next independent stream
}
}Alternative Designs
No response
Risks
No response
Background and motivation
.NET 11 introduced the streamless, non-allocating decoders DeflateDecoder, ZLibDecoder, and GZipDecoder. Each holds a native inflate stream and exposes an instance Decompress(...) method plus a static TryDecompress(...) helper.
Once a decoder finishes a stream, the instance latches an internal _finished flag. Every subsequent Decompress call then returns OperationStatus.Done with bytesConsumed == 0 and bytesWritten == 0 , silently doing nothing. This makes the instance effectively one-shot.
This API addresses the reusability limitation reported in #129090.
Users who want to decode many independent payloads must therefore create and dispose a new decoder for each one, defeating the purpose of the reusable, allocation-conscious instance API (the static TryDecompresy already does create/dispose per call).
API Proposal
API Usage
Alternative Designs
No response
Risks
No response