source: trunk/essentials/dev-lang/perl/lib/fastcwd.pl@ 3221

# By John Bazik
#
# This library is no longer being maintained, and is included for backward
# compatibility with Perl 4 programs which may require it.
#
# In particular, this should not be used as an example of modern Perl
# programming techniques.
#
# Suggested alternative: Cwd
#
# Usage: $cwd = &fastcwd;
#
# This is a faster version of getcwd.  It's also more dangerous because
# you might chdir out of a directory that you can't chdir back into.

sub fastcwd {
        local($odev, $oino, $cdev, $cino, $tdev, $tino);
        local(@path, $path);
        local(*DIR);

        ($cdev, $cino) = stat('.');
        for (;;) {
                ($odev, $oino) = ($cdev, $cino);
                chdir('..');
                ($cdev, $cino) = stat('.');
                last if $odev == $cdev && $oino == $cino;
                opendir(DIR, '.');
                for (;;) {
                        $_ = readdir(DIR);
                        next if $_ eq '.';
                        next if $_ eq '..';

                        last unless $_;
                        ($tdev, $tino) = lstat($_);
                        last unless $tdev != $odev || $tino != $oino;
                }
                closedir(DIR);
                unshift(@path, $_);
        }
        chdir($path = '/' . join('/', @path));
        $path;
}
1;