Fix various compatibility issues with PHP 8

libs/ical/Property/StringValue.php

@@ -0,0 +1,67 @@
+<?php
+
+/*
+ * This file is part of the eluceo/iCal package.
+ *
+ * (c) Markus Poerschke <markus@eluceo.de>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace Eluceo\iCal\Property;
+
+class StringValue implements ValueInterface
+{
+    /**
+     * The value.
+     *
+     * @var string
+     */
+    protected $value;
+
+    public function __construct($value)
+    {
+        $this->value = $value;
+    }
+
+    public function getEscapedValue(): string
+    {
+        $value = $this->value;
+
+        $value = str_replace('\\', '\\\\', $value);
+        $value = str_replace('"', '\\"', $value);
+        $value = str_replace(',', '\\,', $value);
+        $value = str_replace(';', '\\;', $value);
+        $value = str_replace("\n", '\\n', $value);
+        $value = str_replace([
+            "\x00", "\x01", "\x02", "\x03", "\x04", "\x05", "\x06", "\x07",
+            "\x08", "\x09", /* \n*/ "\x0B", "\x0C", "\x0D", "\x0E", "\x0F",
+            "\x10", "\x11", "\x12", "\x13", "\x14", "\x15", "\x16", "\x17",
+            "\x18", "\x19", "\x1A", "\x1B", "\x1C", "\x1D", "\x1E", "\x1F",
+            "\x7F",
+        ], '', $value);
+
+        return $value;
+    }
+
+    /**
+     * @param string $value
+     *
+     * @return $this
+     */
+    public function setValue($value)
+    {
+        $this->value = $value;
+
+        return $this;
+    }
+
+    /**
+     * @return string
+     */
+    public function getValue()
+    {
+        return $this->value;
+    }
+}