/// <summary>
/// Writes the <paramref name="chunk"/> to the file.
/// </summary>
/// <param name="chunk">Must not be null.</param>
/// <returns>Returns the header information for the chunk that has just been written.</returns>
public FileChunkHeader WriteNextChunk(object chunk)
{
Check.IfArgumentNull(chunk, nameof(chunk));
// find chunk id
var chunkId = ChunkAttribute.GetChunkId(chunk);
if (String.IsNullOrEmpty(chunkId))
{
var msg = String.Format(
CultureInfo.InvariantCulture,
"No Chunk Attribute was found for the specified runtime object of type '{0}'.",
chunk.GetType().FullName);
throw new ArgumentException(msg);
}
if (chunkId.HasWildcard())
{
// TODO: this must be pluggable in some way
// for now only digits
chunkId = chunkId.Merge("0000");
}
var chunkTypeId = new FourCharacterCode(chunkId);
var chunkHandler = _handlerMgr.GetChunkHandler(chunkTypeId);
if (!chunkHandler.CanWrite(chunk))
{
var msg = String.Format(
CultureInfo.InvariantCulture,
"The chunk handler '{0}' cannot write the specified runtime object.",
chunkHandler.ChunkId);
throw new ArgumentException(msg);
}
int stackPos = Context.HeaderStack.Count;
var header = PushNewHeader(chunkTypeId);
chunkHandler.Write(Context, chunk);
// wind down the stack to the level it was before we started.
while (Context.HeaderStack.Count > stackPos)
{
var poppedHeader = PopHeader();
WriteChunkHeader(poppedHeader);
}
return(header);
}
/// <summary>
/// Reads the next chunk from the <paramref name="stream"/>.
/// </summary>
/// <param name="stream">Must not be null.</param>
/// <returns>Returns null when there was no runtime chunk type found to represent the chunk read.</returns>
public object ReadNextChunk(Stream stream)
{
Check.IfArgumentNull(stream, nameof(stream));
object chunkObject = null;
var chunk = ReadChunkHeader(stream);
if (chunk != null)
{
Context.ChunkStack.PushChunk(chunk);
var chunkHandler = _handlerMgr.GetChunkHandler(chunk.ChunkId);
if (chunkHandler.CanRead(chunk))
{
chunkObject = chunkHandler.Read(Context);
chunk.RuntimeInstance = chunkObject;
}
// makes sure all of the chunk is 'read' (skipped)
// and aligns the stream position ready for the next chunk.
SkipChunk(chunk);
var poppedChunk = Context.ChunkStack.PopChunk();
if (poppedChunk != null &&
!Object.ReferenceEquals(poppedChunk, chunk))
{
throw new InvalidOperationException("The Chunk Stack has been corrupted.");
}
}
return(chunkObject);
}
