151 lines
3.3 KiB
C#
151 lines
3.3 KiB
C#
using System;
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using System.IO;
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namespace SafeMobileLib
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{
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public class WaveStream : Stream, IDisposable
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{
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private Stream m_Stream;
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private long m_DataPos;
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private long m_Length;
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private WaveFormat m_Format;
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public WaveFormat Format
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{
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get { return m_Format; }
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}
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private string ReadChunk(BinaryReader reader)
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{
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byte[] ch = new byte[4];
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reader.Read(ch, 0, ch.Length);
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return System.Text.Encoding.ASCII.GetString(ch);
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}
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private void ReadHeader()
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{
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BinaryReader Reader = new BinaryReader(m_Stream);
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if (ReadChunk(Reader) != "RIFF")
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throw new Exception("Invalid file format");
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Reader.ReadInt32(); // File length minus first 8 bytes of RIFF description, we don't use it
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if (ReadChunk(Reader) != "WAVE")
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throw new Exception("Invalid file format");
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if (ReadChunk(Reader) != "fmt ")
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throw new Exception("Invalid file format");
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int len = Reader.ReadInt32();
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if (len < 16) // bad format chunk length
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throw new Exception("Invalid file format");
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m_Format = new WaveFormat(22050, 16, 2); // initialize to any format
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m_Format.wFormatTag = Reader.ReadInt16();
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m_Format.nChannels = Reader.ReadInt16();
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m_Format.nSamplesPerSec = Reader.ReadInt32();
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m_Format.nAvgBytesPerSec = Reader.ReadInt32();
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m_Format.nBlockAlign = Reader.ReadInt16();
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m_Format.wBitsPerSample = Reader.ReadInt16();
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// advance in the stream to skip the wave format block
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len -= 16; // minimum format size
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while (len > 0)
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{
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Reader.ReadByte();
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len--;
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}
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// assume the data chunk is aligned
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while(m_Stream.Position < m_Stream.Length && ReadChunk(Reader) != "data")
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;
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if (m_Stream.Position >= m_Stream.Length)
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throw new Exception("Invalid file format");
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m_Length = Reader.ReadInt32();
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m_DataPos = m_Stream.Position;
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Position = 0;
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}
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public WaveStream(string fileName) : this(new FileStream(fileName, FileMode.Open))
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{
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}
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public WaveStream(Stream S)
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{
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m_Stream = S;
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ReadHeader();
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}
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~WaveStream()
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{
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Dispose();
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}
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public void Dispose()
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{
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if (m_Stream != null)
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m_Stream.Close();
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GC.SuppressFinalize(this);
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}
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public override bool CanRead
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{
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get { return true; }
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}
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public override bool CanSeek
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{
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get { return true; }
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}
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public override bool CanWrite
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{
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get { return false; }
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}
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public override long Length
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{
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get { return m_Length; }
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}
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public override long Position
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{
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get { return m_Stream.Position - m_DataPos; }
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set { Seek(value, SeekOrigin.Begin); }
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}
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public override void Close()
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{
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Dispose();
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}
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public override void Flush()
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{
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}
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public override void SetLength(long len)
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{
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throw new InvalidOperationException();
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}
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public override long Seek(long pos, SeekOrigin o)
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{
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switch(o)
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{
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case SeekOrigin.Begin:
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m_Stream.Position = pos + m_DataPos;
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break;
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case SeekOrigin.Current:
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m_Stream.Seek(pos, SeekOrigin.Current);
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break;
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case SeekOrigin.End:
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m_Stream.Position = m_DataPos + m_Length - pos;
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break;
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}
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return this.Position;
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}
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public override int Read(byte[] buf, int ofs, int count)
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{
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int toread = (int)Math.Min(count, m_Length - Position);
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return m_Stream.Read(buf, ofs, toread);
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}
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public override void Write(byte[] buf, int ofs, int count)
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{
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throw new InvalidOperationException();
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}
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}
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}
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