--- /dev/null
+<?php
+/**
+ * Zend Framework (http://framework.zend.com/)
+ *
+ * @link http://github.com/zendframework/zf2 for the canonical source repository
+ * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license http://framework.zend.com/license/new-bsd New BSD License
+ */
+
+namespace Zend\Stdlib;
+
+use Zend\Stdlib\StringWrapper\StringWrapperInterface;
+
+/**
+ * Utility class for handling strings of different character encodings
+ * using available PHP extensions.
+ *
+ * Declared abstract, as we have no need for instantiation.
+ */
+abstract class StringUtils
+{
+ /**
+ * Ordered list of registered string wrapper instances
+ *
+ * @var StringWrapperInterface[]
+ */
+ protected static $wrapperRegistry = null;
+
+ /**
+ * A list of known single-byte character encodings (upper-case)
+ *
+ * @var string[]
+ */
+ protected static $singleByteEncodings = [
+ 'ASCII', '7BIT', '8BIT',
+ 'ISO-8859-1', 'ISO-8859-2', 'ISO-8859-3', 'ISO-8859-4', 'ISO-8859-5',
+ 'ISO-8859-6', 'ISO-8859-7', 'ISO-8859-8', 'ISO-8859-9', 'ISO-8859-10',
+ 'ISO-8859-11', 'ISO-8859-13', 'ISO-8859-14', 'ISO-8859-15', 'ISO-8859-16',
+ 'CP-1251', 'CP-1252',
+ // TODO
+ ];
+
+ /**
+ * Is PCRE compiled with Unicode support?
+ *
+ * @var bool
+ **/
+ protected static $hasPcreUnicodeSupport = null;
+
+ /**
+ * Get registered wrapper classes
+ *
+ * @return string[]
+ */
+ public static function getRegisteredWrappers()
+ {
+ if (static::$wrapperRegistry === null) {
+ static::$wrapperRegistry = [];
+
+ if (extension_loaded('intl')) {
+ static::$wrapperRegistry[] = 'Zend\Stdlib\StringWrapper\Intl';
+ }
+
+ if (extension_loaded('mbstring')) {
+ static::$wrapperRegistry[] = 'Zend\Stdlib\StringWrapper\MbString';
+ }
+
+ if (extension_loaded('iconv')) {
+ static::$wrapperRegistry[] = 'Zend\Stdlib\StringWrapper\Iconv';
+ }
+
+ static::$wrapperRegistry[] = 'Zend\Stdlib\StringWrapper\Native';
+ }
+
+ return static::$wrapperRegistry;
+ }
+
+ /**
+ * Register a string wrapper class
+ *
+ * @param string $wrapper
+ * @return void
+ */
+ public static function registerWrapper($wrapper)
+ {
+ $wrapper = (string) $wrapper;
+ if (! in_array($wrapper, static::$wrapperRegistry, true)) {
+ static::$wrapperRegistry[] = $wrapper;
+ }
+ }
+
+ /**
+ * Unregister a string wrapper class
+ *
+ * @param string $wrapper
+ * @return void
+ */
+ public static function unregisterWrapper($wrapper)
+ {
+ $index = array_search((string) $wrapper, static::$wrapperRegistry, true);
+ if ($index !== false) {
+ unset(static::$wrapperRegistry[$index]);
+ }
+ }
+
+ /**
+ * Reset all registered wrappers so the default wrappers will be used
+ *
+ * @return void
+ */
+ public static function resetRegisteredWrappers()
+ {
+ static::$wrapperRegistry = null;
+ }
+
+ /**
+ * Get the first string wrapper supporting the given character encoding
+ * and supports to convert into the given convert encoding.
+ *
+ * @param string $encoding Character encoding to support
+ * @param string|null $convertEncoding OPTIONAL character encoding to convert in
+ * @return StringWrapperInterface
+ * @throws Exception\RuntimeException If no wrapper supports given character encodings
+ */
+ public static function getWrapper($encoding = 'UTF-8', $convertEncoding = null)
+ {
+ foreach (static::getRegisteredWrappers() as $wrapperClass) {
+ if ($wrapperClass::isSupported($encoding, $convertEncoding)) {
+ $wrapper = new $wrapperClass($encoding, $convertEncoding);
+ $wrapper->setEncoding($encoding, $convertEncoding);
+ return $wrapper;
+ }
+ }
+
+ throw new Exception\RuntimeException(
+ 'No wrapper found supporting "' . $encoding . '"'
+ . (($convertEncoding !== null) ? ' and "' . $convertEncoding . '"' : '')
+ );
+ }
+
+ /**
+ * Get a list of all known single-byte character encodings
+ *
+ * @return string[]
+ */
+ public static function getSingleByteEncodings()
+ {
+ return static::$singleByteEncodings;
+ }
+
+ /**
+ * Check if a given encoding is a known single-byte character encoding
+ *
+ * @param string $encoding
+ * @return bool
+ */
+ public static function isSingleByteEncoding($encoding)
+ {
+ return in_array(strtoupper($encoding), static::$singleByteEncodings);
+ }
+
+ /**
+ * Check if a given string is valid UTF-8 encoded
+ *
+ * @param string $str
+ * @return bool
+ */
+ public static function isValidUtf8($str)
+ {
+ return is_string($str) && ($str === '' || preg_match('/^./su', $str) == 1);
+ }
+
+ /**
+ * Is PCRE compiled with Unicode support?
+ *
+ * @return bool
+ */
+ public static function hasPcreUnicodeSupport()
+ {
+ if (static::$hasPcreUnicodeSupport === null) {
+ ErrorHandler::start();
+ static::$hasPcreUnicodeSupport = defined('PREG_BAD_UTF8_OFFSET_ERROR') && preg_match('/\pL/u', 'a') == 1;
+ ErrorHandler::stop();
+ }
+ return static::$hasPcreUnicodeSupport;
+ }
+}