HashRename.php

<?php  // vim: ts=4 sts=4 sw=4

class HashRename
{
    /***
     * hash_rename
     *
     * @params Hash $hash
     * @params Hash $rule
     */
    function hash_rename (&$hash, $args)
    {
        if ( !is_array($hash) && !is_array($args) ) {
            trigger_error('argument must be hash(array)', E_USER_ERROR);
        }

        $new_hash = array( );

        foreach ($hash as $key => $val) {
            $orig_key = $key;

            if ( array_key_exists($key, $args) ) {
                $key = $args[$key];
            }

            if ( array_key_exists('__prepend', $args) ) {
                $key = $args['__prepend'].$key;
            }

            if ( array_key_exists('__append', $args) ) {
                $key = $key.$args['__append'];
            }

            if ( array_key_exists('__callback', $args) ) {
                $key = call_user_func($args['__callback'], $key);
            }

            if ( array_key_exists('__strict', $args) && array_key_exists($key, $new_hash) ) {
                trigger_error(
                    "duplicate result key [$key] from original key [$orig_key]",
                    E_USER_ERROR
                );
            }

            $new_hash[$key] = $hash[$orig_key];
        }

        $hash = $new_hash;
    }
}