<?php
/**
 * Elgg wrapper functions for multibyte string support.
 *
 * @package Elgg
 * @subpackage Core
 * @author Curverider Ltd
 * @link http://elgg.org/
 */

/**
 * Wrapper function: Returns the result of mb_strtolower if mb_support is present, else the
 * result of strtolower is returned.
 *
 * @param string $string The string.
 * @param string $charset The charset (if multibyte support is present) : default 'UTF8'
 * @return string
 */
function elgg_strtolower($string, $charset = 'UTF8') {
	if (is_callable('mb_strtolower')) {
		return mb_strtolower($string, $charset);
	}

	return strtolower($string);
}

/**
 * Wrapper function: Returns the result of mb_strtoupper if mb_support is present, else the
 * result of strtoupper is returned.
 *
 * @param string $string The string.
 * @param string $charset The charset (if multibyte support is present) : default 'UTF8'
 * @return string
 */
function elgg_strtoupper($string, $charset = 'UTF8') {
	if (is_callable('mb_strtoupper')) {
		return mb_strtoupper($string, $charset);
	}

	return strtoupper($string);
}

/**
 * Wrapper function: Returns the result of mb_substr if mb_support is present, else the
 * result of substr is returned.
 *
 * @param string $string The string.
 * @param int $start Start position.
 * @param int $length Length.
 * @param string $charset The charset (if multibyte support is present) : default 'UTF8'
 * @return string
 */
function elgg_substr($string, $start = 0, $length = null, $charset = 'UTF8') {
	if (is_callable('mb_substr')) {
		return mb_substr($string, $start, $length, $charset);
	}

	return substr($string, $start, $length);
}

// TODO: Other wrapper functions