/// <summary>
/// Returns the directory path of a file path.
/// The returned value the an empty ReadOnlySpan if path is empty or
/// if the file path denotes as root (such as "\", "C:", or "\\server\share").
/// </summary>
/// <remarks>
/// Unlike the string overload, this method will not normalize directory separators.
/// </remarks>
public static ReadOnlySpan <char> GetDirectoryName(ReadOnlySpan <char> path)
{
if (PathInternal.IsEffectivelyEmpty(path))
{
return(ReadOnlySpan <char> .Empty);
}
int end = PathInternal.GetDirectoryNameOffset(path);
return(end >= 0 ? path.Slice(0, end) : ReadOnlySpan <char> .Empty);
}
// Returns the directory path of a file path. This method effectively
// removes the last element of the given file path, i.e. it returns a
// string consisting of all characters up to but not including the last
// backslash ("\") in the file path. The returned value is null if the file
// path is null or if the file path denotes a root (such as "\", "C:", or
// "\\server\share").
public static string GetDirectoryName(string path)
{
if (path == null)
{
return(null);
}
if (PathInternal.IsEffectivelyEmpty(path))
{
throw new ArgumentException(SR.Arg_PathEmpty, nameof(path));
}
path = PathInternal.NormalizeDirectorySeparators(path);
int end = PathInternal.GetDirectoryNameOffset(path);
return(end >= 0 ? path.Substring(0, end) : null);
}
