SafeDispatch/SafeMobileLIB_DLL/WaveStream.cs

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C#
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2024-02-22 16:43:59 +00:00
using System;
using System.IO;
namespace SafeMobileLib
{
public class WaveStream : Stream, IDisposable
{
private Stream m_Stream;
private long m_DataPos;
private long m_Length;
private WaveFormat m_Format;
public WaveFormat Format
{
get { return m_Format; }
}
private string ReadChunk(BinaryReader reader)
{
byte[] ch = new byte[4];
reader.Read(ch, 0, ch.Length);
return System.Text.Encoding.ASCII.GetString(ch);
}
private void ReadHeader()
{
BinaryReader Reader = new BinaryReader(m_Stream);
if (ReadChunk(Reader) != "RIFF")
throw new Exception("Invalid file format");
Reader.ReadInt32(); // File length minus first 8 bytes of RIFF description, we don't use it
if (ReadChunk(Reader) != "WAVE")
throw new Exception("Invalid file format");
if (ReadChunk(Reader) != "fmt ")
throw new Exception("Invalid file format");
int len = Reader.ReadInt32();
if (len < 16) // bad format chunk length
throw new Exception("Invalid file format");
m_Format = new WaveFormat(22050, 16, 2); // initialize to any format
m_Format.wFormatTag = Reader.ReadInt16();
m_Format.nChannels = Reader.ReadInt16();
m_Format.nSamplesPerSec = Reader.ReadInt32();
m_Format.nAvgBytesPerSec = Reader.ReadInt32();
m_Format.nBlockAlign = Reader.ReadInt16();
m_Format.wBitsPerSample = Reader.ReadInt16();
// advance in the stream to skip the wave format block
len -= 16; // minimum format size
while (len > 0)
{
Reader.ReadByte();
len--;
}
// assume the data chunk is aligned
while(m_Stream.Position < m_Stream.Length && ReadChunk(Reader) != "data")
;
if (m_Stream.Position >= m_Stream.Length)
throw new Exception("Invalid file format");
m_Length = Reader.ReadInt32();
m_DataPos = m_Stream.Position;
Position = 0;
}
public WaveStream(string fileName) : this(new FileStream(fileName, FileMode.Open))
{
}
public WaveStream(Stream S)
{
m_Stream = S;
ReadHeader();
}
~WaveStream()
{
Dispose();
}
public void Dispose()
{
if (m_Stream != null)
m_Stream.Close();
GC.SuppressFinalize(this);
}
public override bool CanRead
{
get { return true; }
}
public override bool CanSeek
{
get { return true; }
}
public override bool CanWrite
{
get { return false; }
}
public override long Length
{
get { return m_Length; }
}
public override long Position
{
get { return m_Stream.Position - m_DataPos; }
set { Seek(value, SeekOrigin.Begin); }
}
public override void Close()
{
Dispose();
}
public override void Flush()
{
}
public override void SetLength(long len)
{
throw new InvalidOperationException();
}
public override long Seek(long pos, SeekOrigin o)
{
switch(o)
{
case SeekOrigin.Begin:
m_Stream.Position = pos + m_DataPos;
break;
case SeekOrigin.Current:
m_Stream.Seek(pos, SeekOrigin.Current);
break;
case SeekOrigin.End:
m_Stream.Position = m_DataPos + m_Length - pos;
break;
}
return this.Position;
}
public override int Read(byte[] buf, int ofs, int count)
{
int toread = (int)Math.Min(count, m_Length - Position);
return m_Stream.Read(buf, ofs, toread);
}
public override void Write(byte[] buf, int ofs, int count)
{
throw new InvalidOperationException();
}
}
}