/// <summary>
/// Try to open <paramref name="filename"/> as archive.
/// </summary>
/// <returns>
/// ArcFile object if file is opened successfully, null otherwise.
/// </returns>
public static ArcFile TryOpen(string filename)
{
return(TryOpen(VFS.FindFile(filename)));
}
/// <summary>
/// Try to open <paramref name="filename"/> as archive.
/// </summary>
/// <returns>
/// ArcFile object if file is opened successfully, null otherwise.
/// </returns>
public static ArcFile TryOpen(string filename)
{
var entry = VFS.FindFile(filename);
if (entry.Size < 4)
{
return(null);
}
var ext = new Lazy <string> (() => Path.GetExtension(filename).TrimStart('.').ToLowerInvariant());
var file = VFS.OpenView(entry);
try
{
uint signature = file.View.ReadUInt32(0);
for (;;)
{
var range = FormatCatalog.Instance.LookupSignature <ArchiveFormat> (signature);
// check formats that match filename extension first
if (range.Skip(1).Any()) // if range.Count() > 1
{
range = range.OrderByDescending(f => f.Extensions.Any(e => e == ext.Value));
}
foreach (var impl in range)
{
try
{
var arc = impl.TryOpen(file);
if (null != arc)
{
file = null; // file ownership passed to ArcFile
return(arc);
}
}
catch (OperationCanceledException X)
{
FormatCatalog.Instance.LastError = X;
return(null);
}
catch (Exception X)
{
// ignore failed open attmepts
Trace.WriteLine(string.Format("[{0}] {1}: {2}", impl.Tag, filename, X.Message));
FormatCatalog.Instance.LastError = X;
}
}
if (0 == signature)
{
break;
}
signature = 0;
}
}
finally
{
if (null != file)
{
file.Dispose();
}
}
return(null);
}
