mirror of
https://github.com/CommunityToolkit/dotnet.git
synced 2026-10-28 19:17:46 +08:00
msftbot[bot]
f2969ebb29
## PR type: What kind of change does this PR introduce? <!-- Please uncomment one or more that apply to this PR. --> - Performance improvement <!-- - Bugfix --> <!-- - Feature --> <!-- - Code style update (formatting) --> <!-- - Refactoring (no functional changes, no api changes) --> <!-- - Build or CI related changes --> <!-- - Documentation content changes --> <!-- - Sample app changes --> <!-- - Other... Please describe: --> ## What is the current behavior? <!-- Please describe the current behavior that you are modifying, or link to a relevant issue. --> The `MemoryStream` type wraps a `Memory<byte>` instance, so every time a read/write operation needs to be performed, it will need to use `Memory<T>.Span`, which is relatively expensive to invoke, as it needs to handle multiple possible sources of data. We can use generic types and the value delegate trick (constrained generic struct + interface) to optimize this away. ## What is the new behavior? <!-- Describe how was this issue resolved or changed? --> We now use a `MemoryStream<TSource>` type (which is internal anyway) and have a bunch of `IMemorySource` types specifically supporting `byte[]` and `MemoryManager<byte>` sources with additional optimizations wherever possible. Also, just using this already removes all the overhead of dynamically creating a `Span<T>` from the wrapped `Memory<T>` instance. Here's a benchmark I put together to show the before/after:  The benchmark consists of writing 1024 times a 1024 bytes buffer to a target `Stream` instance. The new `MemoryStream<TSource>` version is almost 25% faster just thanks to this change 🚀 ## PR Checklist Please check if your PR fulfills the following requirements: - [X] Tested code with current [supported SDKs](../readme.md#supported) - [ ] ~~Pull Request has been submitted to the documentation repository [instructions](..\contributing.md#docs).~~ - [ ] ~~Sample in sample app has been added / updated (for bug fixes / features)~~ - [ ] ~~Icon has been created (if new sample) following the [Thumbnail Style Guide and templates](https://github.com/windows-toolkit/WindowsCommunityToolkit-design-assets)~~ - [X] Tests for the changes have been added (for bug fixes / features) (if applicable) - [X] Header has been added to all new source files (run *build/UpdateHeaders.bat*) - [X] Contains **NO** breaking changes
