CSS, JS, and HTML minifier, written in PHP - requires JSMin.php

CSS, JS, HTML Minifier.php

<?php
/* require JSMin class file */
require_once('JSMin.class.php');

class minifier{
    function __Construct(){
    }
    function minifyCSS($CSS) {
        /* remove comments */
        $CSS = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $CSS);
        /* remove tabs, spaces, newlines, etc. */
        $CSS = str_replace(array("\r\n", "\r", "\n", "\t", '  ', '    ', '    '), '', $CSS);
        return $CSS;
    }
    function minifyFile($fileName){
        $input = file_get_contents($fileName);
        if(substr($fileName,-3) == 'css' && stripos($fileName,'.min.css') === false){
            $newFileName = substr($fileName,0,strlen($fileName)-3) . 'min.css';
            $output = $this->minifyCSS($input);
            file_put_contents($newFileName,$output);
        }
        else if(substr($fileName,-2) == 'js' && stripos($fileName,'.min.js') === false){
            $newFileName = substr($fileName,0,strlen($fileName)-2) . 'min.js';
            $output = JSMin::minify($input);
            file_put_contents($newFileName,$output);
        }
        else if(substr($fileName,-3) == 'php' && stripos($fileName, '.min.php') === false){
            $newFileName = substr($fileName,0,strlen($fileName)-3) . 'min.php';
            $output = $this->minifyHTML($input);
            file_put_contents($newFileName,$output);
        }
    }
    function minifyHTML($HTML) {
        $HTML = str_replace("\n?>",' ?>',$HTML);
        /* remove tabs, spaces, newlines, etc. */
        $HTML = str_replace(array("\r\n", "\r", "\n", "\t", '  ', '    ', '    '), '', $HTML);
        /* add space between <?php and first character of code */
        $HTML = preg_replace('/(<?php)/', '$0 ', $HTML);
        /* replace 2 spaces after <?php with one */
        return str_replace('  ',' ',$HTML);
    }
}
?>

may u please guide tht how to use it..?