/// <summary>
/// Create and return a IndexedSequenceProvider to the source file if exists
/// </summary>
/// <param name="sourceFilename">Source file name.</param>
/// <returns>IndexedSequenceProvider object if an index file exists else null.</returns>
public static SidecarFileProvider GetProvider(string sourceFilename)
{
SidecarFileProvider provider = null;
string fileName = sourceFilename + IndexFileExtension;
if (File.Exists(fileName))
{
try
{
provider = new SidecarFileProvider(sourceFilename);
}
catch
{
throw new OperationCanceledException();
}
}
FileInfo fileInfo = new FileInfo(fileName);
if ((provider != null && _sidecarLastWriteTime == fileInfo.LastWriteTime.Date.ToFileTime()) && (_sidecarLength == fileInfo.Length))
{
// Check if the file properties match
if (
provider._header.FileVersion == FileVersion &&
provider._header.LastWriteTime == new FileInfo(sourceFilename).LastWriteTime)
{
return(provider);
}
}
return(null);
}
/// <summary>
/// Initializes a new instance of the VirtualQualitativeSequenceList class with a specified provider,
/// a specified parser, and a specifed sequence count.
/// </summary>
/// <param name="provider">SequencePointer provider from sidecar file.</param>
/// <param name="parser">Parser used to parse sequence data on request.</param>
/// <param name="count">Number of items in the actual file.</param>
public VirtualQualitativeSequenceList(SidecarFileProvider provider, IVirtualSequenceParser parser, int count)
{
_sequenceParser = parser;
_sidecarProvider = provider;
_count = count;
_sequenceDictionary = new Dictionary <int, WeakReference>(_count);
}