private bool getNextDataSegment(out MsvTagDataSegment dataSegment, long endPosition, MpegBox parentBox)
{
// return empty object when we reach data endPosition. If endPosition is set
// to zero, return empty object if we reach end of data.
if (this.br.BaseStream.Position == (0 == endPosition ? this.br.BaseStream.Length : endPosition))
{
dataSegment = null;
return(false);
}
// create new segment and note its offset in the box data
MsvTagDataSegment ds = new MsvTagDataSegment();
ds.offset = this.br.BaseStream.Position;
// offset in file is equal to the start of the containing box, plus eight bytes for
// box's size and uuid markers, plus segment offset from start of box data
ds.absoluteOffset = msvTagBox.AbsoluteOffset() + 8 + ds.offset;
// now get the segment header info and data
ds.size = BU.ReverseToUInt16(this.br.ReadBytes(2)); // size
ds.type = BU.ReverseToUInt32(this.br.ReadBytes(4));
ds.language = BU.ReverseToUInt16(this.br.ReadBytes(2));
ds.unknownProperty = BU.ReverseToUInt16(this.br.ReadBytes(2));
if (0 < ds.size - 10) // if there is any data left after the header, get data
{
ds.segmentData = this.br.ReadBytes(ds.size - 10); // data
}
// all done, verify br's pointer is where it should be
// return finished segment
dataSegment = ds;
return(true);
}
private ArrayList getDataSegments(MemoryStream ms, long endPosition)
{
// read and validate UUID value
// TODO: Implement a real exception handler for this
if ("55534D5421D24FCEBB88695CFAC9C740" !=
BU.ByteArrayToStringHex(br.ReadBytes(16)))
{
throw new MsvDecoderException("Box data supplied is not of type MsvTag.");
}
// read box's internal data size
this.internalSize = BU.ReverseToUInt32(br.ReadBytes(4));
// validate next marker in header
// TODO: Implement a real exception handler for this
if ("4D544454" != BU.ByteArrayToStringHex(br.ReadBytes(4)))
{
throw new MsvDecoderException("Box data supplied is not of type MsvTag.");
}
// read segment count
this.segmentCount = BU.ReverseToUInt16(br.ReadBytes(2));
// we should now be at the start of the first segment
ArrayList result = new ArrayList();
MsvTagDataSegment ds = null;
while (getNextDataSegment(out ds, endPosition, null))
{
result.Add(ds);
}
// TODO: throw exception if we still have a null result
// or if arraylist item count != this.segmentCount
return(result);
}
