<?php
/**
* @version $Id: core.php,v 1.5 2006/02/28 22:12:25 harryf Exp $
* @package utf8
* @subpackage strings
*/

/**
* Define UTF8_CORE as required
*/
if ( !defined('UTF8_CORE') ) {
    define('UTF8_CORE',TRUE);
}

//--------------------------------------------------------------------
/**
* Wrapper round mb_strlen
* Assumes you have mb_internal_encoding to UTF-8 already
* Note: this function does not count bad bytes in the string - these
* are simply ignored
* @param string UTF-8 string
* @return int number of UTF-8 characters in string
* @package utf8
* @subpackage strings
*/
function utf8_strlen($str){
    return mb_strlen($str);
}


//--------------------------------------------------------------------
/**
* Assumes mbstring internal encoding is set to UTF-8
* Wrapper around mb_strpos
* Find position of first occurrence of a string
* @param string haystack
* @param string needle (you should validate this with utf8_is_valid)
* @param integer offset in characters (from left)
* @return mixed integer position or FALSE on failure
* @package utf8
* @subpackage strings
*/
function utf8_strpos($str, $search, $offset = FALSE){
    if ( $offset === FALSE ) {
        return mb_strpos($str, $search);
    } else {
        return mb_strpos($str, $search, $offset);
    }
}

//--------------------------------------------------------------------
/**
* Assumes mbstring internal encoding is set to UTF-8
* Wrapper around mb_strrpos
* Find position of last occurrence of a char in a string
* @param string haystack
* @param string needle (you should validate this with utf8_is_valid)
* @param integer (optional) offset (from left)
* @return mixed integer position or FALSE on failure
* @package utf8
* @subpackage strings
*/
function utf8_strrpos($str, $search, $offset = FALSE){
    if ( $offset === FALSE ) {
        # Emulate behaviour of strrpos rather than raising warning
        if ( empty($str) ) {
            return FALSE;
        }
        return mb_strrpos($str, $search);
    } else {
        if ( !is_int($offset) ) {
            trigger_error('utf8_strrpos expects parameter 3 to be long',E_USER_WARNING);
            return FALSE;
        }
        
        $str = mb_substr($str, $offset);
        
        if ( FALSE !== ( $pos = mb_strrpos($str, $search) ) ) {
            return $pos + $offset;
        }
        
        return FALSE;
    }
}

//--------------------------------------------------------------------
/**
* Assumes mbstring internal encoding is set to UTF-8
* Wrapper around mb_substr
* Return part of a string given character offset (and optionally length)
* @param string
* @param integer number of UTF-8 characters offset (from left)
* @param integer (optional) length in UTF-8 characters from offset
* @return mixed string or FALSE if failure
* @package utf8
* @subpackage strings
*/
function utf8_substr($str, $offset, $length = FALSE){
    if ( $length === FALSE ) {
        return mb_substr($str, $offset);
    } else {
        return mb_substr($str, $offset, $length);
    }
}

//--------------------------------------------------------------------
/**
* Assumes mbstring internal encoding is set to UTF-8
* Wrapper around mb_strtolower
* Make a string lowercase
* Note: The concept of a characters "case" only exists is some alphabets
* such as Latin, Greek, Cyrillic, Armenian and archaic Georgian - it does
* not exist in the Chinese alphabet, for example. See Unicode Standard
* Annex #21: Case Mappings
* @param string
* @return mixed either string in lowercase or FALSE is UTF-8 invalid
* @package utf8
* @subpackage strings
*/
function utf8_strtolower($str){
    return mb_strtolower($str);
}

//--------------------------------------------------------------------
/**
* Assumes mbstring internal encoding is set to UTF-8
* Wrapper around mb_strtoupper
* Make a string uppercase
* Note: The concept of a characters "case" only exists is some alphabets
* such as Latin, Greek, Cyrillic, Armenian and archaic Georgian - it does
* not exist in the Chinese alphabet, for example. See Unicode Standard
* Annex #21: Case Mappings
* @param string
* @return mixed either string in lowercase or FALSE is UTF-8 invalid
* @package utf8
* @subpackage strings
*/
function utf8_strtoupper($str){
    return mb_strtoupper($str);
}
