next/prev cat nav for cat archive

<?php
//alchyhmyth 2011
//transformationpowertools.com/wordpress
//
//a simple next/prev category navigation for category archives
//
foreach(get_categories() as $all_cat) {  $cat_ids[] = $all_cat->term_id; }
  $this_cat = get_query_var('cat');
  $this_cat_position = array_search( $this_cat, $cat_ids ); ?>

<?php $prev_cat_position = $this_cat_position -1;
      if( $prev_cat_position >=0 ) {
      $prev_cat_id = array_slice( $cat_ids, $prev_cat_position, 1 );
    echo '<a href="' . get_category_link($prev_cat_id[0]) . '">&laquo; ' . get_category($prev_cat_id[0])->name . '</a>'; } ?>

<?php $next_cat_position = $this_cat_position +1;
      if( $next_cat_position < count($cat_ids) ) {
      $next_cat_id = array_slice( $cat_ids, $next_cat_position, 1 );
echo '<a href="' . get_category_link($next_cat_id[0]) . '">' . get_category($next_cat_id[0])->name . ' &raquo;</a>'; } ?>