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khosb/includes/kohana/system/utf8/substr.php

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2013-10-10 02:44:53 +00:00
<?php defined('SYSPATH') OR die('No direct script access.');
/**
* UTF8::substr
*
* @package Kohana
* @author Kohana Team
* @copyright (c) 2007-2012 Kohana Team
* @copyright (c) 2005 Harry Fuecks
* @license http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt
*/
function _substr($str, $offset, $length = NULL)
{
if (UTF8::is_ascii($str))
return ($length === NULL) ? substr($str, $offset) : substr($str, $offset, $length);
// Normalize params
$str = (string) $str;
$strlen = UTF8::strlen($str);
$offset = (int) ($offset < 0) ? max(0, $strlen + $offset) : $offset; // Normalize to positive offset
$length = ($length === NULL) ? NULL : (int) $length;
// Impossible
if ($length === 0 OR $offset >= $strlen OR ($length < 0 AND $length <= $offset - $strlen))
return '';
// Whole string
if ($offset == 0 AND ($length === NULL OR $length >= $strlen))
return $str;
// Build regex
$regex = '^';
// Create an offset expression
if ($offset > 0)
{
// PCRE repeating quantifiers must be less than 65536, so repeat when necessary
$x = (int) ($offset / 65535);
$y = (int) ($offset % 65535);
$regex .= ($x == 0) ? '' : ('(?:.{65535}){'.$x.'}');
$regex .= ($y == 0) ? '' : ('.{'.$y.'}');
}
// Create a length expression
if ($length === NULL)
{
$regex .= '(.*)'; // No length set, grab it all
}
// Find length from the left (positive length)
elseif ($length > 0)
{
// Reduce length so that it can't go beyond the end of the string
$length = min($strlen - $offset, $length);
$x = (int) ($length / 65535);
$y = (int) ($length % 65535);
$regex .= '(';
$regex .= ($x == 0) ? '' : ('(?:.{65535}){'.$x.'}');
$regex .= '.{'.$y.'})';
}
// Find length from the right (negative length)
else
{
$x = (int) (-$length / 65535);
$y = (int) (-$length % 65535);
$regex .= '(.*)';
$regex .= ($x == 0) ? '' : ('(?:.{65535}){'.$x.'}');
$regex .= '.{'.$y.'}';
}
preg_match('/'.$regex.'/us', $str, $matches);
return $matches[1];
}