schema 0.0.1

Schema

Library for converting classes to and from binary. Provides a C# Roslyn generator that automatically implements conversion logic for simple classes.

Credits

• @jefffhaynes, as their BinarySerializer attribute library inspired the schema attributes for configuring how binary data is read.
• @Sergio0694, as their BinaryPack generator inspired the schema source generator used to generate read/write methods.

Usage

Setting up a project

Copy this project into your solution, and then add the following into any other projects that you wish to automatically generate code for:

<ItemGroup>
  <ProjectReference Include="../Schema/Schema.csproj" PrivateAssets="all" OutputItemType="Analyzer" />
</ItemGroup>

Implementing binary schema classes

To write a binary schema class, you must first do the following steps:

1. Mark it as partial.
2. Have it implement the IBinaryConvertible interface (a combination of the IBinarySerializable and IBinaryDeserializable interfaces).

Then, based on how complicated your schema class is, you can either choose to automatically or manually implement Read()/Write() methods.

Automatically

For most schema classes, you should be able to use the automatic code generator.

All you have to do is annotate the schema class with the [BinarySchema] attribute; this will flag to the generator that it should implement read/write methods for this class. It will then look into all fields/properties in the schema class, and attempt to implement read/write logic in the same order that the fields/properties appear.

Any nested schema classes will be automatically read/written as expected.

Some types require additional attributes in order to clarify any ambiguity. For example, booleans require a [IntegerFormat(SchemaIntegerType.###)] attribute to know what type of integer to read, which it will then compare to 0.

Any readonly primitives will treated as assertions, which is useful for validating things like magic text or padding.

Manually

For complicated schema classes, such as ones that use decompression logic or pointers, you'll need to implement the read/write logic manually.

Specifically, you'll need to implement both a Read(IEndianBinaryReader er) and Write(ISubEndianBinaryWriter ew) method. The EndianBinaryReader and EndianBinaryWriter classes provide many helpful methods for reading/writing a number of different primitive formats, including basic ones such as byte/int/float, but also more complex/unique ones such as Half (two-byte float) and un16 (unsigned normalized 16-bit float).

Similar to the automatic process, you can nest schema classes and manually read/write them by calling their Read()/Write() methods. This can allow you to automatically generate subsections, so only the most complex logic needs to be manually written.

How to use a binary schema class

To convert a given schema class to or from binary, simply instantiate an EndianBinaryReader or EndianBinaryWriter and pass it into the corresponding Read() or Write() methods in the schema class. You must use the EndianBinaryReader/EndianBinaryWriter defined within this project, as this adds more functionality.