90 lines
2.3 KiB
PHP
90 lines
2.3 KiB
PHP
<?php
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interface TStringFunc
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{
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public function substr($str, $start, $length = null);
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public function strlen($str);
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}
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class TStringFunc_Core
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implements TStringFunc {
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public function substr($str, $start, $length = null)
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{
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// specifying a null $length would return an empty string
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if ($length === null) {
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return substr($str, $start);
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}
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return substr($str, $start, $length);
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}
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public function strlen($str)
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{
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return strlen($str);
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}
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}
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class TStringFunc_Mbstring
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implements TStringFunc {
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public function substr($str, $start, $length = null)
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{
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/**
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* We need to set the charset parameter, which is the second
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* optional parameter and the first optional parameter can't
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* be null or false as a "magic" value because that would
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* cause an empty string to be returned, so we need to
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* actually calculate the proper length value.
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*/
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if ($length === null) {
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$length = $this->strlen($str) - $start;
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}
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return mb_substr($str, $start, $length, '8bit');
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}
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public function strlen($str)
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{
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return mb_strlen($str, '8bit');
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}
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}
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class TStringFuncFactory
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{
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private static $_instance;
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/**
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* Get the Singleton instance of TStringFunc implementation that is
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* compatible with the current system's mbstring.func_overload settings.
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*
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* @return TStringFunc
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*/
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public static function create()
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{
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if (!self::$_instance) {
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self::_setInstance();
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}
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return self::$_instance;
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}
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private static function _setInstance()
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{
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/**
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* Cannot use str* functions for byte counting because multibyte
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* characters will be read a single bytes.
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*
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* See: http://us.php.net/manual/en/mbstring.overload.php
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*/
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if (ini_get('mbstring.func_overload') & 2) {
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self::$_instance = new TStringFunc_Mbstring();
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}
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/**
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* mbstring is not installed or does not have function overloading
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* of the str* functions enabled so use PHP core str* functions for
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* byte counting.
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*/
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else {
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self::$_instance = new TStringFunc_Core();
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}
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}
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}
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