parseUNC

fn parseUNC(comptime T: type, path: []const T) WindowsUNC(T) {
    assert(path.len >= 2 and PathType.windows.isSep(T, path[0]) and PathType.windows.isSep(T, path[1]));
    const any_sep = switch (T) {
        u8 => "/\\",
        u16 => std.unicode.wtf8ToWtf16LeStringLiteral("/\\"),
        else => @compileError("only u8 (WTF-8) and u16 (WTF-16LE) are supported"),
    };
    // For the server, the first path separator after the initial two is always
    // the terminator of the server name, even if that means the server name is
    // zero-length.
    const server_end = mem.findAnyPos(T, path, 2, any_sep) orelse return .{
        .server = path[2..path.len],
        .sep_after_server = false,
        .share = path[path.len..path.len],
        .sep_after_share = false,
    };
    // For the share, there can be any number of path separators between the server
    // and the share, so we want to skip over all of them instead of just looking for
    // the first one.
    var it = mem.tokenizeAny(T, path[server_end + 1 ..], any_sep);
    const share = it.next() orelse return .{
        .server = path[2..server_end],
        .sep_after_server = true,
        .share = path[server_end + 1 .. server_end + 1],
        .sep_after_share = false,
    };
    return .{
        .server = path[2..server_end],
        .sep_after_server = true,
        .share = share,
        .sep_after_share = it.index != it.buffer.len,
    };
}