public static ReadOnlySpan<char> ParentDirectory(this ReadOnlySpan<char> filePath)
{
if (filePath.IsNullOrEmpty())
return TypeConstants.NullStringSpan;
var dirSep = filePath.IndexOf(PclExport.Instance.DirSep) != -1
? PclExport.Instance.DirSep
: filePath.IndexOf(PclExport.Instance.AltDirSep) != -1
? PclExport.Instance.AltDirSep
: (char)0;
if (dirSep == 0)
return TypeConstants.NullStringSpan;
MemoryExtensions.TrimEnd(filePath, dirSep).SplitOnLast(dirSep, out var first, out _);
return first;
}
