GDROMExplorer/SEGATools/Stream/SubStream.cs

// Decompiled with JetBrains decompiler
// Type: SEGATools.Stream.SubStream
// Assembly: SEGATools, Version=1.0.3.0, Culture=neutral, PublicKeyToken=611be24fdeb07e08
// MVID: D631183F-57B1-40A1-B502-5364D288307A
// Assembly location: SEGATools.dll

using System;
using System.IO;

namespace SEGATools.Stream
{
  public class SubStream : System.IO.Stream
  {
    private System.IO.Stream sourceStream;
    private long startOffset;
    private long length;
    private bool disposeSourceStream;
    private bool disposed;

    public SubStream(System.IO.Stream source, long offset, long length, bool autoReleaseSource)
    {
      if (offset < 0L)
        throw new ArgumentOutOfRangeException(nameof (offset));
      if (length < 0L)
        throw new ArgumentOutOfRangeException(nameof (length));
      this.disposed = false;
      this.sourceStream = source;
      this.startOffset = offset;
      this.length = length;
      this.disposeSourceStream = autoReleaseSource;
      this.Seek(0L, SeekOrigin.Begin);
    }

    public override bool CanWrite => !this.disposed && this.sourceStream != null && this.sourceStream.CanWrite;

    public override bool CanSeek => !this.disposed && this.sourceStream != null && this.sourceStream.CanSeek;

    public override bool CanRead => !this.disposed && this.sourceStream != null && this.sourceStream.CanRead;

    public override long Length => this.length;

    public override long Position
    {
      get => this.sourceStream.Position - this.startOffset;
      set => this.Seek(value, SeekOrigin.Begin);
    }

    public override long Seek(long offset, SeekOrigin origin)
    {
      this.CheckCanSeek();
      switch (origin)
      {
        case SeekOrigin.Begin:
          return this.sourceStream.Seek(this.startOffset + offset, origin) - this.startOffset;
        case SeekOrigin.Current:
          return this.sourceStream.Seek(offset, origin) - this.startOffset;
        case SeekOrigin.End:
          return this.sourceStream.Seek(this.startOffset + this.length + offset, SeekOrigin.Begin) - this.startOffset;
        default:
          throw new ArgumentException(string.Format("invalid origin \"{0}\": only Begin, Current and End are valid values", (object) origin), nameof (origin));
      }
    }

    public override int Read(byte[] buffer, int offset, int count)
    {
      this.CheckBufferArguments(buffer, offset, count);
      this.CheckCanRead();
      int count1 = (int) Math.Min((long) count, this.startOffset + this.length - this.Position);
      return this.sourceStream.Read(buffer, offset, count1);
    }

    public override void Write(byte[] buffer, int offset, int count)
    {
      this.CheckBufferArguments(buffer, offset, count);
      this.CheckCanWrite();
      if (this.Length - this.Position < (long) count)
        throw new ArgumentException();
      this.sourceStream.Write(buffer, offset, count);
    }

    public override void WriteByte(byte value)
    {
      this.CheckCanWrite();
      if (this.Length - this.Position < 1L)
        throw new ArgumentException();
      this.sourceStream.WriteByte(value);
    }

    public override void Close()
    {
      if (this.sourceStream == null || !this.disposeSourceStream)
        return;
      this.sourceStream.Close();
    }

    public override void SetLength(long value) => throw new NotSupportedException();

    public override void Flush() => throw new NotSupportedException();

    private void CheckBufferArguments(byte[] buffer, int offset, int count)
    {
      if (buffer == null)
        throw new ArgumentNullException(nameof (buffer));
      if (offset < 0)
        throw new ArgumentOutOfRangeException(nameof (offset));
      if (count < 0)
        throw new ArgumentOutOfRangeException(nameof (count));
      if (offset + count > buffer.Length)
        throw new ArgumentException();
    }

    private void CheckCanWrite()
    {
      if (!this.CanWrite)
        throw new NotSupportedException();
      if (this.disposed)
        throw new ObjectDisposedException(nameof (SubStream));
    }

    private void CheckCanRead()
    {
      if (!this.CanRead)
        throw new NotSupportedException();
      if (this.disposed)
        throw new ObjectDisposedException(nameof (SubStream));
    }

    private void CheckCanSeek()
    {
      if (!this.CanSeek)
        throw new NotSupportedException();
      if (this.disposed)
        throw new ObjectDisposedException(nameof (SubStream));
    }

    public new virtual void Dispose()
    {
      this.Dispose(true);
      GC.SuppressFinalize((object) this);
    }

    protected new virtual void Dispose(bool disposing)
    {
      if (this.disposed)
        return;
      if (disposing)
        this.Close();
      this.disposed = true;
    }
  }
}