Authme Class

<?php
/*
 *  Copyright (C) 2015-2016  Leonardosc
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 *  21/01/2015
*/

class AuthMe {

    /* TIPOS DE HASH DO AUTHME */
    const MD5 = "md5";
    const SHA256 = "sha256";
    const SHA1 = "sha1";
    const WHIRLPOOL = "whirlpool";
    const MD5VB = "md5vb";
    const PLAINTEXT = "plaintext";

    /* CONEXÃO DO BANCO DE DADOS. */
    private $conection;

    /* NOME DA TASBELA DO AUTHME */
    private $authme_table;

    /* HASH USADA */
    private $algorithm;

    /* ESTA É A METODO CONSTRUTOR DA CLASSE *

       PARAMETROS
       $db_host = Ip do seu banco de dados mysql;
       $db_user = Nome de usuario do seu banco de dados mysql.
       $db_pass = Senha do seu banco de dados mysql;
       $db_name = Nome do database do mysql;
       $authme_table = Nome da tabela do authme;
       $algo = Tipo de hash que seu authme está utilizando;
     */
    public function __construct($db_host, $db_user, $db_pass, $db_name, $authme_table, $algo) {
        $this->authme_table = $authme_table;
        $this->algorithm = $algo;
        @$this->conection = mysqli_connect($db_host, $db_user, $db_pass) or die(mysqli_connect_error());
        @mysqli_select_db($this->conection, $db_name) or die(mysqli_error($this->conection));
    }

    /* METODO DESTRUTOR, O CONTRARIO DO CONSTRUTOR '-' */
    public function __destruct() {
        if (is_object($this->conection)) {
            $this->conection->close();
            unset($this->algorithm);
            unset($this->authme_table);
        }
    }

    /* METODO USADO PARA AUTENTICAR UM USUARIO

       PARAMETROS
       $user = Nome de usuario.
       $pass = Senha do usuario.

    */
    public function authenticate($user, $pass) {
        $user = addslashes($user);
        $query = mysqli_query($this->conection, "SELECT password FROM {$this->authme_table} WHERE username='{$user}'");

        if (mysqli_num_rows($query) == 1) {
        	$ret = mysqli_fetch_array($query);
            $hash_pass = $ret[0];
            return self::compare($pass, $hash_pass);
        } else {
            return false;
        }
    }

    /* METODO USADO PARA REGISTRAR UM USUARIO

       PARAMETROS
       $user = Nome de usuario.
       $pass = Senha do usuario.
       $ip = Ip do usuario.
    */
    public function register($user, $pass, $ip = "0.0.0.0") {
        $user = addslashes($user);
        $pass = addslashes(self::AMHash($pass));

        if (self::isUsernameRegistered($user)) {
            return false;
        }

        return mysqli_query($this->conection, "INSERT INTO {$this->authme_table} (`username`, `password`, `ip`, `lastlogin`, `x`, `y`, `z`) VALUES ('{$user}','{$pass}','{$ip}','0','0','0','0')");
    }

    /* METODO USADO PARA ALTERAR A SENHA DE UM USUARIO

       PARAMETROS
       $user = Nome de usuario.
       $newpass = Nova senha do usuario.

    */
    public function changePassword($username, $newpass) {
        if (!self::isUsernameRegistered($username)) {
            return false;
        }

        $username = addslashes($username);
        $newpass = addslashes(self::AMHash($newpass));

        return mysqli_query($this->conection, "UPDATE {$this->authme_table} SET password='$newpass' WHERE username='$username'");
    }

    /* METODO USADO PARA VERIFICAR SE UM DETERMINADO IP ESTA REGISTRADO.

       PARAMETROS
       $ip = Ip que deseja verificar.
   */
    public function isIpRegistered($ip) {
        $ip = addslashes($ip);
        $query = mysqli_query($this->conection, "SELECT ip FROM {$this->authme_table} WHERE ip='{$ip}'");
        return mysqli_num_rows($query) >= 1;
    }

    /* METODO USADO PARA VERIFICAR SE UM DETERMINADO NOME DE USUARIO ESTA REGISTRADO.

       PARAMETROS
       $user = Nome de usuario que deseja verificar.
   */
    public function isUsernameRegistered($user) {
        $user = addslashes($user);
        $query = mysqli_query($this->conection, "SELECT username FROM {$this->authme_table} WHERE username='{$user}'");
        return mysqli_num_rows($query) >= 1;
    }

    /* METODOS PRIVADOS, USO SOMENTE DA CLASSE. */
    private function compare($pass, $hash_pass) {
        switch ($this->algorithm) {

            case "sha256":
                $shainfo = explode("$", $hash_pass);
                $pass = hash("sha256", $pass).$shainfo[2];
                return strcasecmp($shainfo[3], hash('sha256', $pass)) == 0;

            case "sha1":
                return strcasecmp($hash_pass, hash('sha1', $pass)) == 0;

            case "md5":
                return strcasecmp($hash_pass, hash('md5', $pass)) == 0;

            case "whirlpool":
                return strcasecmp($hash_pass, hash('whirlpool', $pass)) == 0;

            case "md5vb":
                $shainfo = explode("$", $hash_pass);
                $pass = hash("md5", $pass).$shainfo[2];
                return strcasecmp($shainfo[3], hash('md5', $pass)) == 0;

            case "plaintext":
                return $hash_pass == $pass;

            default:
                return false;
        }
    }

    private function AMHash($pass) {
        switch ($this->algorithm) {

            case "sha256":
                $salt = self::createSalt();
                return "\$SHA\$".$salt."\$".hash("sha256", hash('sha256', $pass).$salt);

            case "sha1":
                return hash("sha1", $pass);

            case "md5":
                return hash("sha1", $pass);

            case "whirlpool":
                return hash("sha1", $pass);

            case "md5vb":
                $salt = self::createSalt();
                return "\$MD5vb\$".$salt."\$".hash("md5", hash('md5', $pass).$salt);

            case "plaintext":
                return $pass;

            default:
                return false;
        }
    }

    private function createSalt() {
        $salt = "";
        for ($i = 0; $i < 20; $i++) {
            $salt .= rand(0, 9);
        }
        return substr(hash("sha1", $salt), 0, 16);
    }
}