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Brotli-Builder/BrotliLib/Brotli/Streaming/BrotliFileReader.cs

70 lines
2.3 KiB
C#

using BrotliLib.Brotli.Components;
using BrotliLib.Brotli.Dictionary;
using BrotliLib.Brotli.Output;
using BrotliLib.Brotli.Parameters;
using BrotliLib.Markers;
using BrotliLib.Markers.Serialization.Reader;
using BrotliLib.Serialization;
namespace BrotliLib.Brotli.Streaming{
/// <summary>
/// Provides a streaming meta-block deserializer as an alternative to <see cref="BrotliFileStructure"/>.
/// </summary>
public sealed class BrotliFileReader : IBrotliFileStream{
public static BrotliFileReader FromBytes(byte[] bytes, BrotliDictionary? dictionary = null, in MarkerSettings markerSettings = default){
return FromBytes(new BitStream(bytes), dictionary, markerSettings);
}
public static BrotliFileReader FromBytes(BitStream bits, BrotliDictionary? dictionary = null, in MarkerSettings markerSettings = default){
return new BrotliFileReader(bits, markerSettings, dictionary ?? BrotliFileParameters.Default.Dictionary);
}
// Instance
public BrotliFileParameters Parameters { get; }
public BrotliGlobalState State => state.Clone();
private readonly IMarkedBitReader reader;
private readonly BrotliGlobalState state;
private bool isAtEnd = false;
private BrotliFileReader(BitStream bits, in MarkerSettings markerSettings, BrotliDictionary dictionary){
this.reader = markerSettings.CreateBitReader(bits);
this.Parameters = new BrotliFileParameters.Builder{
WindowSize = ReadHeader(),
Dictionary = dictionary
}.Build();
this.state = new BrotliGlobalState(Parameters);
}
// Output
public void AddOutputCallback(IBrotliOutput callback){
state.AddOutputCallback(callback);
}
public void RemoveOutputCallback(IBrotliOutput callback){
state.RemoveOutputCallback(callback);
}
// Reader
private WindowSize ReadHeader(){
return WindowSize.Deserialize(reader, NoContext.Value);
}
public MetaBlock? NextMetaBlock(){
if (isAtEnd){
return null;
}
var (metaBlock, isLast) = MetaBlock.Deserialize(reader, state);
isAtEnd = isLast;
return metaBlock;
}
}
}