/// <summary>
/// Read the container header section. (The 'RIFF' or 'LIST' header.)
/// This method verifies the header is well-formed and caches the
/// container'stream FOURCC type.
/// </summary>
private void ReadRiffHeader()
{
RiffChunk header = new RiffChunk();
// Riff chunks must be WORD aligned
if (!IsAligned(this.containerOffset, 2))
{
throw new InvalidOperationException("The chunk is not aligned");
}
// Offset must be positive.
if (this.containerOffset < 0)
{
throw new InvalidOperationException("The container offset needs to be positive");
}
// Seek to the start of the container.
this.stream.Position = this.containerOffset;
// Read the header
header.FCC = (FourCC)this.br.ReadUInt32();
header.Size = this.br.ReadUInt32();
header.FCCList = (FourCC)this.br.ReadUInt32();
// Make sure the header ID matches what the caller expected.
if (header.FCC != this.fccId)
{
throw new InvalidOperationException("We don't have the right FourCC code");
}
// The size given in the RIFF header does not include the 8-byte header.
// However, our _containerOffset is the offset from the start of the
// header. Therefore our container size = listed size + size of header.
this.containerSize = header.Size + SizeOfRiffChunk;
this.fccType = header.FCCList;
this.currentChunkOffset = this.containerOffset + SizeOfRiffList;
this.ReadChunkHeader();
}
/// <summary>
/// Read the container header section. (The 'RIFF' or 'LIST' header.)
/// This method verifies the header is well-formed and caches the
/// container'stream FOURCC type.
/// </summary>
private void ReadRiffHeader()
{
RiffChunk header = new RiffChunk();
// Riff chunks must be WORD aligned
if (!IsAligned(this.containerOffset, 2))
{
throw new InvalidOperationException("The chunk is not aligned");
}
// Offset must be positive.
if (this.containerOffset < 0)
{
throw new InvalidOperationException("The container offset needs to be positive");
}
// Seek to the start of the container.
this.stream.Position = this.containerOffset;
// Read the header
header.FCC = (FourCC)this.br.ReadUInt32();
header.Size = this.br.ReadUInt32();
header.FCCList = (FourCC)this.br.ReadUInt32();
// Make sure the header ID matches what the caller expected.
if (header.FCC != this.fccId)
{
throw new InvalidOperationException("We don't have the right FourCC code");
}
// The size given in the RIFF header does not include the 8-byte header.
// However, our _containerOffset is the offset from the start of the
// header. Therefore our container size = listed size + size of header.
this.containerSize = header.Size + SizeOfRiffChunk;
this.fccType = header.FCCList;
this.currentChunkOffset = this.containerOffset + SizeOfRiffList;
this.ReadChunkHeader();
}
