<?php
/**
 * PHPUnit
 *
 * Copyright (c) 2001-2014, Sebastian Bergmann <sebastian@phpunit.de>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *
 *   * Neither the name of Sebastian Bergmann nor the names of his
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * @package    PHPUnit
 * @subpackage Util
 * @author     Sebastian Bergmann <sebastian@phpunit.de>
 * @copyright  2001-2014 Sebastian Bergmann <sebastian@phpunit.de>
 * @license    http://www.opensource.org/licenses/BSD-3-Clause  The BSD 3-Clause License
 * @link       http://www.phpunit.de/
 * @since      File available since Release 3.6.0
 */

/**
 * String helpers.
 *
 * @package    PHPUnit
 * @subpackage Util
 * @author     Sebastian Bergmann <sebastian@phpunit.de>
 * @copyright  2001-2014 Sebastian Bergmann <sebastian@phpunit.de>
 * @license    http://www.opensource.org/licenses/BSD-3-Clause  The BSD 3-Clause License
 * @link       http://www.phpunit.de/
 * @since      Class available since Release 3.6.0
 */
class PHPUnit_Util_String
{
    /**
     * Converts a string to UTF-8 encoding.
     *
     * @param  string $string
     * @return string
     */
    public static function convertToUtf8($string)
    {
        if (!self::isUtf8($string)) {
            if (function_exists('mb_convert_encoding')) {
                $string = mb_convert_encoding($string, 'UTF-8');
            } else {
                $string = utf8_encode($string);
            }
        }

        return $string;
    }

    /**
     * Checks a string for UTF-8 encoding.
     *
     * @param  string  $string
     * @return boolean
     */
    protected static function isUtf8($string)
    {
        $length = strlen($string);

        for ($i = 0; $i < $length; $i++) {
            if (ord($string[$i]) < 0x80) {
                $n = 0;
            } elseif ((ord($string[$i]) & 0xE0) == 0xC0) {
                $n = 1;
            } elseif ((ord($string[$i]) & 0xF0) == 0xE0) {
                $n = 2;
            } elseif ((ord($string[$i]) & 0xF0) == 0xF0) {
                $n = 3;
            } else {
                return false;
            }

            for ($j = 0; $j < $n; $j++) {
                if ((++$i == $length) || ((ord($string[$i]) & 0xC0) != 0x80)) {
                    return false;
                }
            }
        }

        return true;
    }
}
