Added unit testing for PHP 7.2

Updated README.md
Separated preg_replace code into an method

Author: JanPetterMG

.travis.yml

@@ -4,6 +4,7 @@ env:
 sudo: false
 language: php
 php:
+  - 7.2
   - 7.1
   - 7.0
   - 5.6

README.md

@@ -4,15 +4,14 @@
 [![Test Coverage](https://api.codeclimate.com/v1/badges/319c474eb3a681c50ba3/test_coverage)](https://codeclimate.com/github/VIPnytt/UserAgentParser/test_coverage)
 [![License](https://poser.pugx.org/VIPnytt/UserAgentParser/license)](https://github.com/VIPnytt/UserAgentParser/blob/master/LICENSE)
 [![Packagist](https://img.shields.io/packagist/v/vipnytt/useragentparser.svg)](https://packagist.org/packages/vipnytt/useragentparser)
-[![Chat](https://badges.gitter.im/VIPnytt/UserAgentParser.svg)](https://gitter.im/VIPnytt/UserAgentParser)
 
 # User-Agent parser for robot rule sets
 Parser and group determiner optimized for ``robots.txt``, ``X-Robots-tag`` and ``Robots-meta-tag`` usage cases.
 
 [![SensioLabsInsight](https://insight.sensiolabs.com/projects/1386c14c-546c-4c42-ac55-91ea3a3a1ae1/big.png)](https://insight.sensiolabs.com/projects/1386c14c-546c-4c42-ac55-91ea3a3a1ae1)
 
 #### Requirements:
-- PHP [5.5+](http://php.net/supported-versions.php)
+- PHP 5.5+ or 7.0+
 
 ## Installation
 The library is available for install via [Composer](https://getcomposer.org). Just add this to your `composer.json` file:

src/UserAgentParser.php

@@ -25,11 +25,6 @@ class UserAgentParser
      */
     const RFC_README = 'https://tools.ietf.org/html/rfc7231#section-5.5.3';
 
-    /**
-     * PREG pattern for valid characters
-     */
-    const PREG_PATTERN = '/[^\x21-\x7E]/';
-
     /**
      * Origin product
      * @var string
@@ -91,7 +86,7 @@ private function validateProduct()
     {
         $this->blacklistCheck($this->product);
         $this->originProduct = $this->product;
-        if ($this->originProduct !== ($this->product = preg_replace(self::PREG_PATTERN, '', $this->product))) {
+        if ($this->originProduct !== ($this->product = $this->strip($this->product))) {
             trigger_error("Product name contains invalid characters. Truncated to `$this->product`.", E_USER_NOTICE);
         }
         if (empty($this->product)) {
@@ -122,6 +117,17 @@ private function blacklistCheck($input)
         return true;
     }
 
+    /**
+     * Strip invalid characters
+     *
+     * @param string|string[] $string
+     * @return string|string[]|null
+     */
+    private function strip($string)
+    {
+        return preg_replace('/[^\x21-\x7E]/', '', $string);
+    }
+
     /**
      * Validate the Version and it's format
      * @link https://tools.ietf.org/html/rfc7231#section-5.5.3
@@ -187,7 +193,7 @@ public function getMostSpecific(array $userAgents)
         $array = [];
         foreach ($userAgents as $string) {
             // Strip non-US-ASCII characters
-            $array[$string] = strtolower(preg_replace(self::PREG_PATTERN, '', $string));
+            $array[$string] = strtolower($this->strip($string));
         }
         foreach (array_map('strtolower', $this->getUserAgents()) as $generated) {
             if (($result = array_search($generated, $array)) !== false) {