--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/plugins/libcalendaring/lib/Sabre/VObject/Reader.php	Sat Jan 13 08:57:56 2018 -0500
@@ -0,0 +1,223 @@
+<?php
+
+namespace Sabre\VObject;
+
+/**
+ * VCALENDAR/VCARD reader
+ *
+ * This class reads the vobject file, and returns a full element tree.
+ *
+ * TODO: this class currently completely works 'statically'. This is pointless,
+ * and defeats OOP principals. Needs refactoring in a future version.
+ *
+ * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
+ */
+class Reader {
+
+    /**
+     * If this option is passed to the reader, it will be less strict about the
+     * validity of the lines.
+     *
+     * Currently using this option just means, that it will accept underscores
+     * in property names.
+     */
+    const OPTION_FORGIVING = 1;
+
+    /**
+     * If this option is turned on, any lines we cannot parse will be ignored
+     * by the reader.
+     */
+    const OPTION_IGNORE_INVALID_LINES = 2;
+
+    /**
+     * Parses the file and returns the top component
+     *
+     * The options argument is a bitfield. Pass any of the OPTIONS constant to
+     * alter the parsers' behaviour.
+     *
+     * @param string $data
+     * @param int $options
+     * @return Node
+     */
+    static function read($data, $options = 0) {
+
+        // Normalizing newlines
+        $data = str_replace(array("\r","\n\n"), array("\n","\n"), $data);
+
+        $lines = explode("\n", $data);
+
+        // Unfolding lines
+        $lines2 = array();
+        foreach($lines as $line) {
+
+            // Skipping empty lines
+            if (!$line) continue;
+
+            if ($line[0]===" " || $line[0]==="\t") {
+                $lines2[count($lines2)-1].=substr($line,1);
+            } else {
+                $lines2[] = $line;
+            }
+
+        }
+
+        unset($lines);
+
+        reset($lines2);
+
+        return self::readLine($lines2, $options);
+
+    }
+
+    /**
+     * Reads and parses a single line.
+     *
+     * This method receives the full array of lines. The array pointer is used
+     * to traverse.
+     *
+     * This method returns null if an invalid line was encountered, and the
+     * IGNORE_INVALID_LINES option was turned on.
+     *
+     * @param array $lines
+     * @param int $options See the OPTIONS constants.
+     * @return Node
+     */
+    static private function readLine(&$lines, $options = 0) {
+
+        $line = current($lines);
+        $lineNr = key($lines);
+        next($lines);
+
+        // Components
+        if (strtoupper(substr($line,0,6)) === "BEGIN:") {
+
+            $componentName = strtoupper(substr($line,6));
+            $obj = Component::create($componentName);
+
+            $nextLine = current($lines);
+
+            while(strtoupper(substr($nextLine,0,4))!=="END:") {
+
+                $parsedLine = self::readLine($lines, $options);
+                $nextLine = current($lines);
+
+                if (is_null($parsedLine)) {
+                    continue;
+                }
+                $obj->add($parsedLine);
+
+                if ($nextLine===false)
+                    throw new ParseException('Invalid VObject. Document ended prematurely.');
+
+            }
+
+            // Checking component name of the 'END:' line.
+            if (substr($nextLine,4)!==$obj->name) {
+                throw new ParseException('Invalid VObject, expected: "END:' . $obj->name . '" got: "' . $nextLine . '"');
+            }
+            next($lines);
+
+            return $obj;
+
+        }
+
+        // Properties
+        //$result = preg_match('/(?P<name>[A-Z0-9-]+)(?:;(?P<parameters>^(?<!:):))(.*)$/',$line,$matches);
+
+        if ($options & self::OPTION_FORGIVING) {
+            $token = '[A-Z0-9-\._]+';
+        } else {
+            $token = '[A-Z0-9-\.]+';
+        }
+        $parameters = "(?:;(?P<parameters>([^:^\"]|\"([^\"]*)\")*))?";
+        $regex = "/^(?P<name>$token)$parameters:(?P<value>.*)$/i";
+
+        $result = preg_match($regex,$line,$matches);
+
+        if (!$result) {
+            if ($options & self::OPTION_IGNORE_INVALID_LINES) {
+                return null;
+            } else {
+                throw new ParseException('Invalid VObject, line ' . ($lineNr+1) . ' did not follow the icalendar/vcard format');
+            }
+        }
+
+        $propertyName = strtoupper($matches['name']);
+        $propertyValue = preg_replace_callback('#(\\\\(\\\\|N|n))#',function($matches) {
+            if ($matches[2]==='n' || $matches[2]==='N') {
+                return "\n";
+            } else {
+                return $matches[2];
+            }
+        }, $matches['value']);
+
+        $obj = Property::create($propertyName, $propertyValue);
+
+        if ($matches['parameters']) {
+
+            foreach(self::readParameters($matches['parameters']) as $param) {
+                $obj->add($param);
+            }
+
+        }
+
+        return $obj;
+
+
+    }
+
+    /**
+     * Reads a parameter list from a property
+     *
+     * This method returns an array of Parameter
+     *
+     * @param string $parameters
+     * @return array
+     */
+    static private function readParameters($parameters) {
+
+        $token = '[A-Z0-9-]+';
+
+        $paramValue = '(?P<paramValue>[^\"^;]*|"[^"]*")';
+
+        $regex = "/(?<=^|;)(?P<paramName>$token)(=$paramValue(?=$|;))?/i";
+        preg_match_all($regex, $parameters, $matches,  PREG_SET_ORDER);
+
+        $params = array();
+        foreach($matches as $match) {
+
+            if (!isset($match['paramValue'])) {
+
+                $value = null;
+
+            } else {
+
+                $value = $match['paramValue'];
+
+                if (isset($value[0]) && $value[0]==='"') {
+                    // Stripping quotes, if needed
+                    $value = substr($value,1,strlen($value)-2);
+                }
+
+                $value = preg_replace_callback('#(\\\\(\\\\|N|n|;|,))#',function($matches) {
+                    if ($matches[2]==='n' || $matches[2]==='N') {
+                        return "\n";
+                    } else {
+                        return $matches[2];
+                    }
+                }, $value);
+
+            }
+
+            $params[] = new Parameter($match['paramName'], $value);
+
+        }
+
+        return $params;
+
+    }
+
+
+}