main/lib/text/stringhelper.php

См. документацию.

<?php
/**
 * Bitrix Framework
 * @package    bitrix
 * @subpackage main
 * @copyright  2001-2018 Bitrix
 */
 
namespace Bitrix\Main\Text;
 
/**
 * String functions
 * @package    bitrix
 * @subpackage main
 */
class StringHelper
{
    /**
     * Regular uppercase with result cache
     *
     * @param $str
     *
     * @return mixed
     */
    public static function strtoupper($str)
    {
        static $cache;
 
        if (empty($cache[$str]))
        {
            $cache[$str] = mb_strtoupper($str);
        }
 
        return $cache[$str];
    }
 
    /**
     * Changes registry from CamelCase to snake_case
     *
     * @param $str
     *
     * @return string
     */
    public static function camel2snake($str)
    {
        return mb_strtolower(preg_replace('/(.)([A-Z])/', '$1_$2', $str));
    }
 
    /**
     * Changes registry from snake_case or SNAKE_CASE to CamelCase
     *
     * @param $str
     *
     * @return mixed
     */
    public static function snake2camel($str)
    {
        $str = str_replace('_', ' ', mb_strtolower($str));
        return str_replace(' ', '', ucwords($str));
    }
}