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- <?php
- /**
- * UTF8::substr
- *
- * @package Kohana
- * @author Kohana Team
- * @copyright (c) 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];
- }
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