internal void CopyAtom(AtomInfo atom, Stream output)
{
Contract.Requires(atom != null);
Contract.Requires(output != null);
Contract.Requires(output.CanWrite);
_stream.Position = atom.Start;
_stream.CopyRangeTo(output, atom.Size);
}
internal byte[] ReadAtom(AtomInfo atom)
{
Contract.Requires(atom != null);
Contract.Ensures(Contract.Result <byte[]>() != null);
_stream.Position = atom.Start;
using (var reader = new BinaryReader(_stream, Encoding.Default, true))
return(reader.ReadBytes((int)atom.Size));
}
internal void DescendToAtom(params string[] hierarchy)
{
Contract.Requires(hierarchy != null);
Contract.Requires(Contract.ForAll(hierarchy, fourCC => !string.IsNullOrEmpty(fourCC)));
Contract.Requires(Contract.ForAll(hierarchy, fourCC => fourCC.Length == 4));
_stream.Position = 0;
_atomInfoStack.Clear();
using (var reader = new BinaryReader(_stream, Encoding.GetEncoding(1252), true))
{
foreach (string fourCC in hierarchy)
{
do
{
var subAtom = new AtomInfo((uint)_stream.Position, reader.ReadUInt32BigEndian(),
reader.ReadFourCC());
if (subAtom.Size == 0)
{
throw new IOException(Resources.Mp4AtomNotFoundError);
}
if (subAtom.FourCC == fourCC)
{
_atomInfoStack.Push(subAtom);
// Some containers also contain data, which needs to be skipped:
switch (fourCC)
{
case "meta":
_stream.Seek(4, SeekOrigin.Current);
break;
case "stsd":
_stream.Seek(8, SeekOrigin.Current);
break;
case "mp4a":
_stream.Seek(28, SeekOrigin.Current);
break;
}
break;
}
_stream.Position = subAtom.End;
} while (_stream.Position < (_atomInfoStack.Count == 0 ? _stream.Length : _atomInfoStack.Peek().End));
}
}
}
internal AtomInfo[] GetChildAtomInfo()
{
Contract.Ensures(Contract.Result <AtomInfo[]>() != null);
var result = new List <AtomInfo>();
using (var reader = new BinaryReader(_stream, Encoding.GetEncoding(1252), true))
{
_stream.Position = _atomInfoStack.Count == 0 ? 0 : _atomInfoStack.Peek().Start + 8;
while (_stream.Position < (_atomInfoStack.Count == 0 ? _stream.Length : _atomInfoStack.Peek().End))
{
var childAtom = new AtomInfo((uint)_stream.Position, reader.ReadUInt32BigEndian(), reader.ReadFourCC());
result.Add(childAtom);
_stream.Position = childAtom.End;
}
}
return(result.ToArray());
}
