81 lines
2.2 KiB
C#
81 lines
2.2 KiB
C#
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using System.Security.Cryptography;
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namespace MareSynchronos.Utils;
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// Calculates the hash of content read or written to a stream
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public class HashingStream : Stream
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{
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private readonly Stream _stream;
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private readonly HashAlgorithm _hashAlgo;
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private bool _finished = false;
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public bool DisposeUnderlying { get; set; } = true;
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public Stream UnderlyingStream { get => _stream; }
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public HashingStream(Stream underlyingStream, HashAlgorithm hashAlgo)
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{
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_stream = underlyingStream;
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_hashAlgo = hashAlgo;
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}
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protected override void Dispose(bool disposing)
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{
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base.Dispose(disposing);
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if (!DisposeUnderlying)
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return;
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if (!_finished)
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_stream.Dispose();
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_hashAlgo.Dispose();
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}
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public override bool CanRead => _stream.CanRead;
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public override bool CanSeek => false;
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public override bool CanWrite => _stream.CanWrite;
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public override long Length => _stream.Length;
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public override long Position { get => _stream.Position; set => throw new NotSupportedException(); }
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public override void Flush()
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{
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_stream.Flush();
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}
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public override int Read(byte[] buffer, int offset, int count)
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{
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ObjectDisposedException.ThrowIf(_finished, this);
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int n = _stream.Read(buffer, offset, count);
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if (n > 0)
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_hashAlgo.TransformBlock(buffer, offset, n, buffer, offset);
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return n;
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}
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public override long Seek(long offset, SeekOrigin origin)
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{
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throw new NotSupportedException();
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}
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public override void SetLength(long value)
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{
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ObjectDisposedException.ThrowIf(_finished, this);
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_stream.SetLength(value);
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}
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public override void Write(byte[] buffer, int offset, int count)
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{
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ObjectDisposedException.ThrowIf(_finished, this);
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_stream.Write(buffer, offset, count);
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_hashAlgo.TransformBlock(buffer, offset, count, buffer, offset);
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}
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public byte[] Finish()
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{
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if (_finished)
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return _hashAlgo.Hash!;
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_hashAlgo.TransformFinalBlock(Array.Empty<byte>(), 0, 0);
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_finished = true;
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if (DisposeUnderlying)
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_stream.Dispose();
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return _hashAlgo.Hash!;
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}
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}
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