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July 4, 2008, July 04, 2008 09:44, permalink

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<?php
/*
 * This is a test of a rules based iterative algorithm...
 *
 */


$rules = array();
/*
 * type = # == numeric, @ = alpha
 * lower = lower boundary
 * upper = upper boundary
 *
 */
$rules[] = array('type'=>'#', 'lower'=>0, 'upper'=>5);
// If a rule is running over characters and it is case-sensitive,
// then we need to define the sequence to have the upper case letters first
$rules[] = array('type'=>'@', 'lower'=>'A', 'upper'=>'D');
$rules[] = array('type'=>'#', 'lower'=>1, 'upper'=>3);
$rules[] = array('type'=>'@', 'lower'=>'A', 'upper'=>'B');

iterate('/%0%%1%-%2%-%3%/', $rules, "mycall");

function mycall($data, &$rules) {
    echo "<strong>" .$data . "</strong><br />";
    return true;
}

function iterate($format, &$rules, $call = null) {
    $continue = true;
    while ($continue) {
        updateCounts(array_reverse($rules, true), $rules);

        /* Setup initial values */
        $vars = array();
        $continue = false;
        foreach ($rules as $key => $val) {
            $vars["%$key%"] = $val['cur'];
            if (!($val['cur'] == $val['upper'])) {
                $continue = true;
            }
        }

        if (!is_null($call)) {
            if (!call_user_func($call, str_replace(array_keys($vars), array_values($vars), $format), $rules)) {
                return;
            }
        } else {
            echo str_replace(array_keys($vars), array_values($vars), $format) . "<br />";
        }
    }
}

function updateCounts($arr, &$rules) {
    foreach ($arr as $key => $val) {
        if (!isset($val['cur'])) {
            /* No current value, start with the lower one */
            $rules[$key]['cur'] = $rules[$key]['lower'];
            continue;
        }

        if ($val['cur'] == $val['upper']) {
            /* Reset to lower, continue */
            $rules[$key]['cur'] = $rules[$key]['lower'];
            continue;
        }

        /* Add One, exit function */
        switch ($rules[$key]['type']) {
            case '#':
                $rules[$key]['cur']++;
                break;
            case '@':
                $chr = ord($rules[$key]['cur']);
                //need to jump over none alphabetic chars here...
                if ($chr == 90) {
                    $chr = 97;
                } else {
                    $chr++;
                }
                $rules[$key]['cur'] = chr($chr);
                break;
            default:
                die('Unknown Rule Type');
        }
        return true;
    }
}