/// <summary>
/// Reads a sequencePointer from a binary stream.
/// </summary>
/// <param name="stream">The stream to deserialize from.</param>
/// <returns>The SequencePointer object.</returns>
private static SequencePointer ReadPointer(FileStream stream)
{
SequencePointer pointer = new SequencePointer();
BinaryReader reader = new BinaryReader(stream);
pointer.StartingLine = reader.ReadInt32();
pointer.StartingIndex = reader.ReadInt64();
pointer.EndingIndex = reader.ReadInt64();
string alphabetName = new string(reader.ReadChars(3));
foreach (IAlphabet alphabet in Alphabets.All)
{
if (alphabet.Name.StartsWith(alphabetName, StringComparison.Ordinal))
{
pointer.AlphabetName = alphabet.Name;
break;
}
}
if (string.IsNullOrEmpty(pointer.AlphabetName))
{
throw new FileFormatException("alphabet");
}
return(pointer);
}
/// <summary>
/// Serialize an object to a binary outputStream.
/// </summary>
/// <param name="stream">The outputStream to serialize to.</param>
/// <param name="pointer">Sequence pointer obejct to serialize</param>
private static void WritePointer(FileStream stream, SequencePointer pointer)
{
BinaryWriter writer = new BinaryWriter(stream);
writer.Write(pointer.StartingLine);
writer.Write(pointer.StartingIndex);
writer.Write(pointer.EndingIndex);
// Writing only first three chars of alphabet name
writer.Write(pointer.AlphabetName.Substring(0, 3).ToCharArray());
}
/// <summary>
/// Gets the index of a qualitative sequence within the list.
/// Throws a NotSupportedException when attempting to set the position
/// since VirtualSequenceList is read-only.
/// </summary>
/// <param name="index">The zero-based index of the qualitative sequence in the list.</param>
/// <returns>The qualitative sequence found at the specified index.</returns>
public IQualitativeSequence this[int index]
{
get
{
QualitativeSequence virtualQualitativeSequence;
if (_sequenceDictionary.ContainsKey(index))
{
virtualQualitativeSequence = _sequenceDictionary[index].Target as QualitativeSequence;
if (virtualQualitativeSequence != null)
{
return(virtualQualitativeSequence);
}
_sequenceDictionary.Remove(index);
}
SequencePointer pointer = _sidecarProvider[index];
// Get the alphabet from alphabet name.
IAlphabet alphabet = Alphabets.All.Single(A => A.Name.Equals(pointer.AlphabetName));
virtualQualitativeSequence = new QualitativeSequence(alphabet)
{
ID = (_sequenceParser as FastQ.FastQParser).GetSequenceID(pointer),
VirtualQualitativeSequenceProvider =
new FileVirtualQualitativeSequenceProvider(_sequenceParser, pointer)
};
if (pointer.EndingIndex - pointer.StartingIndex < virtualQualitativeSequence.VirtualQualitativeSequenceProvider.BlockSize)
{
virtualQualitativeSequence.VirtualQualitativeSequenceProvider.BlockSize = (int)(pointer.EndingIndex - pointer.StartingIndex);
}
virtualQualitativeSequence.IsReadOnly = CreateSequenceAsReadOnly;
_sequenceDictionary.Add(index, new WeakReference(virtualQualitativeSequence, false));
return(virtualQualitativeSequence);
}
set
{
throw new NotSupportedException(Properties.Resource.NotSupportedInVirtualSequence);
}
}
/// <summary>
/// Indexer with which one can access the sequences in the indexed file.
/// </summary>
/// <param name="index">Zero based index of the SequencePointer to fetch.</param>
/// <returns>SequencePointer object at the specified index.</returns>
public SequencePointer this[int index]
{
get
{
if (index >= _header.SequenceCount || index < 0)
{
throw new ArgumentOutOfRangeException("index");
}
_inputStream.Seek(_contentsOffset, SeekOrigin.Begin);
// find the entry for the item at the given index
_inputStream.Seek(index * PayloadBlockSize, SeekOrigin.Current);
// Read the required sequence pointer
SequencePointer loadedSequence = ReadPointer(_inputStream) as SequencePointer;
return(loadedSequence);
}
}
/// <summary>
/// Initializes a new instance of the Bio.IO.FileVirtualQualitativeSequenceProvider
/// class to hold a sequence pointer with a parser.
/// </summary>
/// <param name="parser">A virtual parser object.</param>
/// <param name="pointer">The sequence pointer.</param>
public FileVirtualQualitativeSequenceProvider(IVirtualSequenceParser parser, SequencePointer pointer)
{
if (parser == null)
{
throw new ArgumentNullException("parser");
}
if (pointer == null)
{
throw new ArgumentNullException("pointer");
}
_parser = parser;
_count = (int)(pointer.EndingIndex - pointer.StartingIndex);
SequencePointerInstance = pointer;
//set the default DV properties.
_virtualData = new VirtualData <Sequence>
{
BlockSize = FileLoadHelper.DefaultBlockSize,
MaxNumberOfBlocks = FileLoadHelper.DefaultMaxNumberOfBlocks
};
}
