/// <summary>
/// Read the sample count of a waveform file.
/// </summary>
/// <param name="filePath">Waveform file to read sample count.</param>
/// <returns>Sample count of the waveform file. if -1 is returned.</returns>
public static int ReadSampleCount(string filePath)
{
if (string.IsNullOrEmpty(filePath))
{
throw new ArgumentNullException("filePath");
}
WaveFormat format;
try
{
FileStream fs = new FileStream(filePath,
FileMode.Open, FileAccess.Read, FileShare.Read);
try
{
using (BinaryReader br = new BinaryReader(fs))
{
fs = null;
Riff riff = new Riff();
riff.LoadHead(br);
RiffChunk fmt = new RiffChunk();
fmt.Load(br, Riff.IdFormat);
format = new WaveFormat();
format.Load(fmt.GetData());
int chunkId = 0;
int dataSize = 0;
do
{
chunkId = br.ReadInt32();
dataSize = br.ReadInt32();
if (dataSize < 0)
{
string message = string.Format(CultureInfo.InvariantCulture,
"Invalid data size [{0}], which should not be negative integer.",
dataSize);
throw new InvalidDataException(message);
}
long currPos = br.BaseStream.Position;
long newPos = br.BaseStream.Seek(dataSize, SeekOrigin.Current);
if (newPos != currPos + dataSize)
{
string message = string.Format(CultureInfo.InvariantCulture,
"Invalid data size [{0}], which may be too large.",
dataSize);
throw new InvalidDataException(message);
}
}
while (Riff.IdData != chunkId);
if (Riff.IdData != chunkId)
{
string message = string.Format(CultureInfo.InvariantCulture,
"Invalid waveform format for not data chunk found in file {0}",
filePath);
throw new InvalidDataException(message);
}
return dataSize / (format.BlockAlign * format.Channels);
}
}
finally
{
if (null != fs)
{
fs.Dispose();
}
}
}
catch (InvalidDataException ide)
{
string message = string.Format(CultureInfo.InvariantCulture,
"Fail to read sample count of waveform file [{0}] for invalid data.",
filePath);
throw new InvalidDataException(message, ide);
}
catch (EndOfStreamException ese)
{
string message = string.Format(CultureInfo.InvariantCulture,
"Fail to read sample count of waveform file [{0}] for no enough data.",
filePath);
throw new InvalidDataException(message, ese);
}
}
/// <summary>
/// Exactly do cut operation.
/// </summary>
/// <param name="samplePosition">Start sample position.</param>
/// <param name="sampleNumber">Waveform sample length.</param>
/// <returns>Riff of the cut piece.</returns>
private Riff DoCut(int samplePosition, int sampleNumber)
{
if (this.Format.Channels != 1)
{
string message = string.Format(CultureInfo.InvariantCulture,
"Does not support to cut part waveform in a multi-channel wave file instance.");
throw new NotSupportedException(message);
}
Riff riff = new Riff();
riff.RiffType = Riff.IdWave;
RiffChunk fmt = this.Riff.GetChunk(Riff.IdFormat);
riff.Chunks.Add(fmt);
RiffChunk data = new RiffChunk();
data.Id = Riff.IdData;
int startbyte = samplePosition * this.Format.BlockAlign;
int sizebyte = sampleNumber * this.Format.BlockAlign;
data.SetData(new byte[sizebyte]);
byte[] src = this.GetSoundData();
int maxSizeToCopy = src.Length - startbyte;
int sizeToCopy = sizebyte <= maxSizeToCopy ? sizebyte : maxSizeToCopy;
Array.Copy(src, startbyte, data.GetData(), 0, sizeToCopy);
riff.Chunks.Add(data);
data.Size = sizebyte;
riff.Size = fmt.TotalSize + data.TotalSize + 4;
return riff;
}
public static WaveFormat ReadFormat(string filePath)
{
WaveFormat format;
try
{
using (FileStream fs =
new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read))
using (BinaryReader br = new BinaryReader(fs))
{
Riff riff = new Riff();
riff.LoadHead(br);
RiffChunk fmt = new RiffChunk();
fmt.Load(br, Riff.IdFormat);
format = new WaveFormat();
format.Load(fmt.GetData());
}
}
catch (InvalidDataException ide)
{
string message = string.Format(CultureInfo.InvariantCulture,
"Fail to read format of waveform file [{0}] for invalid data.",
filePath);
throw new InvalidDataException(message, ide);
}
return format;
}