/// <summary>
/// Pushes a new chunk up the stack.
/// </summary>
/// <param name="chunk">Must not be null.</param>
/// <remarks>The <paramref name="chunk"/> is added as a child to the current top chunk.</remarks>
public void PushChunk(FileChunk chunk)
{
Check.IfArgumentNull(chunk, nameof(chunk));
var parentChunk = CurrentChunk;
// maintain child-chunks on parent.
if (parentChunk != null)
{
parentChunk.SubChunks.Add(chunk);
}
chunkStack.Push(chunk);
}
/// <summary>
/// Skips reading any remaining data for the <paramref name="chunk"/>.
/// </summary>
/// <param name="chunk">Must not be null.</param>
/// <remarks>The underlying file stream is aligned using the <see cref="IStreamNavigator"/> implementation if available.</remarks>
protected void SkipChunk(FileChunk chunk)
{
Check.IfArgumentNull(chunk, nameof(chunk));
Check.IfArgumentNull(chunk.DataStream, nameof(chunk.DataStream));
EndStream(chunk.DataStream);
if (_streamNavigator != null)
{
// after skipping the chunk length re-align position of the root stream.
// sub streams may refuse to move if they are at their end.
_streamNavigator.AlignPosition(Context.ChunkFile.BaseStream);
}
}
/// <summary>
/// Pushes a new chunk up the stack.
/// </summary>
/// <param name="chunk">Must not be null.</param>
/// <remarks>The <paramref name="chunk"/> is added as a child to the current top chunk.</remarks>
public void PushChunk(FileChunk chunk)
{
Contract.Requires(chunk != null);
Check.IfArgumentNull(chunk, "chunk");
var parentChunk = this.CurrentChunk;
// maintain child-chunks on parent.
if (parentChunk != null)
{
parentChunk.SubChunks.Add(chunk);
}
this.chunkStack.Push(chunk);
}
protected void SkipChunk(FileChunk chunk)
{
Contract.Requires(chunk != null);
Contract.Requires(chunk.DataStream != null);
Check.IfArgumentNull(chunk, "chunk");
Check.IfArgumentNull(chunk.DataStream, "chunk.DataStream");
this.EndStream(chunk.DataStream);
if (this.streamNavigator != null)
{
// after skipping the chunk length re-align position of the root stream.
// sub streams may refuse to move if they are at their end.
this.streamNavigator.AlignPosition(this.context.ChunkFile.BaseStream);
}
}
public FileChunk ReadChunkHeader(Stream stream)
{
Contract.Requires(stream != null);
Check.IfArgumentNull(stream, "stream");
if (this.ValidateStreamPosition(8))
{
var chunk = new FileChunk();
chunk.ChunkId = FourCharacterCode.ReadFrom(stream);
chunk.DataLength = this.numberReader.ReadUInt32AsInt64(stream);
chunk.ParentPosition = stream.Position;
chunk.FilePosition = this.context.ChunkFile.BaseStream.Position;
chunk.DataStream = new SubStream(stream, chunk.DataLength);
return(chunk);
}
return(null);
}
/// <summary>
/// Reads the first (header) fields of a chunk from the <paramref name="stream"/>.
/// </summary>
/// <param name="stream">Must not be null.</param>
/// <returns>Returns null when the stream position does not allow to read the header.</returns>
/// <remarks>The following properties are set on the returned <see cref="FileChunk"/>.
/// <see cref="P:FileChunk.ChunkId"/>, <see cref="P:FileChunk.DataLength"/>,
/// <see cref="P:FileChunk.ParentPosition"/>, <see cref="P:FileChunk.FilePosition"/>
/// and <see cref="P:FileChunk.DataStream"/>.</remarks>
public FileChunk ReadChunkHeader(Stream stream)
{
Check.IfArgumentNull(stream, nameof(stream));
if (ValidateStreamPosition(8))
{
var chunk = new FileChunk
{
ChunkId = FourCharacterCode.ReadFrom(stream),
DataLength = _numberReader.ReadUInt32AsInt64(stream),
ParentPosition = stream.Position,
FilePosition = Context.ChunkFile.BaseStream.Position
};
chunk.DataStream = new SubStream(stream, chunk.DataLength);
return(chunk);
}
return(null);
}
/// <summary>
/// Contract specification.
/// </summary>
/// <param name="chunk">Must not be null.</param>
/// <returns>No Contract.</returns>
bool IFileChunkHandler.CanRead(FileChunk chunk)
{
Contract.Requires(chunk != null);
throw new System.NotImplementedException();
}
/// <summary>
/// Indicates if the specified <paramref name="chunk"/> can be read by the handler.
/// </summary>
/// <param name="chunk">Must not be null.</param>
/// <returns>Returns true if the <paramref name="chunk"/> can be read.</returns>
public override bool CanRead(FileChunk chunk)
{
Check.IfArgumentNull(chunk, nameof(chunk));
return(chunk.DataStream != null && chunk.DataStream.CanRead);
}
