[core] Backported str_starts_with, str_ends_with and str_contains from php 8 (#2318)

lib/php8backports.php

@@ -0,0 +1,32 @@
+<?php
+/**
+ * This file is part of RSS-Bridge, a PHP project capable of generating RSS and
+ * Atom feeds for websites that don't have one.
+ *
+ * For the full license information, please view the UNLICENSE file distributed
+ * with this source code.
+ *
+ * @package	Core
+ * @license	http://unlicense.org/ UNLICENSE
+ * @link	https://github.com/rss-bridge/rss-bridge
+ */
+
+// based on https://github.com/laravel/framework/blob/8.x/src/Illuminate/Support/Str.php
+
+if (!function_exists('str_starts_with')) {
+	function str_starts_with($haystack, $needle) {
+		return (string)$needle !== '' && strncmp($haystack, $needle, strlen($needle)) === 0;
+	}
+}
+
+if (!function_exists('str_ends_with')) {
+	function str_ends_with($haystack, $needle) {
+		return $needle !== '' && substr($haystack, -strlen($needle)) === (string)$needle;
+	}
+}
+
+if (!function_exists('str_contains')) {
+	function str_contains($haystack, $needle) {
+		return $needle !== '' && mb_strpos($haystack, $needle) !== false;
+	}
+}

lib/rssbridge.php

@@ -80,6 +80,7 @@ require_once PATH_LIB . 'XPathAbstract.php';
 require_once PATH_LIB . 'html.php';
 require_once PATH_LIB . 'error.php';
 require_once PATH_LIB . 'contents.php';
+require_once PATH_LIB . 'php8backports.php';
 
 // Vendor
 define('MAX_FILE_SIZE', 10000000); /* Allow larger files for simple_html_dom */