From 92e447043fd89a272270b95500521df2de9f1588 Mon Sep 17 00:00:00 2001
From: Edward Whiting <edwhiting@bigpond.com>
Date: Tue, 18 Aug 2020 13:17:24 +1000
Subject: [PATCH] Increase the resilience of CalendarParserImpl to superfluous
 newline characters between objects in the input file.

---
 .../ical4j/data/CalendarParserImpl.java       | 23 ++++++++++++-------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/main/java/net/fortuna/ical4j/data/CalendarParserImpl.java b/src/main/java/net/fortuna/ical4j/data/CalendarParserImpl.java
index d4f2499ff..4459a1a3a 100644
--- a/src/main/java/net/fortuna/ical4j/data/CalendarParserImpl.java
+++ b/src/main/java/net/fortuna/ical4j/data/CalendarParserImpl.java
@@ -112,6 +112,8 @@ private void parseCalendar(final StreamTokenizer tokeniser, Reader in,
 
         handler.startCalendar();
 
+        absorbWhitespace(tokeniser, in);
+
         // parse calendar properties..
         propertyListParser.parse(tokeniser, in, handler);
 
@@ -180,7 +182,8 @@ private void parseCalendarList(final StreamTokenizer tokeniser, Reader in,
         int ntok = assertToken(tokeniser, in, Calendar.BEGIN, false, true);
         while (ntok != StreamTokenizer.TT_EOF) {
             parseCalendar(tokeniser, in, handler);
-            ntok = absorbWhitespace(tokeniser, in, true);
+            absorbWhitespace(tokeniser, in);
+            ntok = nextToken(tokeniser, in, true);
         }
     }
 
@@ -214,7 +217,8 @@ public void parse(final StreamTokenizer tokeniser, Reader in,
                 } else if (!CompatibilityHints.isHintEnabled(CompatibilityHints.KEY_RELAXED_PARSING)) {
                     throw new ParserException("Invalid property name", getLineNumber(tokeniser, in));
                 }
-                absorbWhitespace(tokeniser, in, false);
+                absorbWhitespace(tokeniser, in);
+                nextToken(tokeniser, in, false);
                 // assertToken(tokeniser, StreamTokenizer.TT_WORD);
             }
         }
@@ -394,7 +398,8 @@ private void parse(final StreamTokenizer tokeniser, Reader in,
 
             while (Component.BEGIN.equals(tokeniser.sval)) {
                 componentParser.parse(tokeniser, in, handler);
-                absorbWhitespace(tokeniser, in, false);
+                absorbWhitespace(tokeniser, in);
+                nextToken(tokeniser, in, false);
                 // assertToken(tokeniser, StreamTokenizer.TT_WORD);
             }
         }
@@ -425,6 +430,7 @@ private void parse(final StreamTokenizer tokeniser, Reader in,
             handler.startComponent(name);
 
             assertToken(tokeniser, in, StreamTokenizer.TT_EOL);
+            absorbWhitespace(tokeniser, in);
 
             propertyListParser.parse(tokeniser, in, handler);
 
@@ -579,10 +585,8 @@ private String getSvalIgnoringBom(StreamTokenizer tokeniser, Reader in, String t
      * @return int value of the ttype field of the tokeniser
      * @throws IOException
      */
-    private int absorbWhitespace(final StreamTokenizer tokeniser, Reader in, boolean ignoreEOF) throws IOException, ParserException {
-        // HACK: absorb extraneous whitespace between components (KOrganizer)..
-        int ntok;
-        while ((ntok = nextToken(tokeniser, in, ignoreEOF)) == StreamTokenizer.TT_EOL) {
+    private void absorbWhitespace(final StreamTokenizer tokeniser, Reader in) throws IOException, ParserException {
+        while (nextToken(tokeniser, in, true) == StreamTokenizer.TT_EOL) {
             if (log.isTraceEnabled()) {
                 log.trace("Absorbing extra whitespace..");
             }
@@ -590,7 +594,10 @@ private int absorbWhitespace(final StreamTokenizer tokeniser, Reader in, boolean
         if (log.isTraceEnabled()) {
             log.trace("Aborting: absorbing extra whitespace complete");
         }
-        return ntok;
+        /* In effect, we only want to absorb extra newlines after the current
+         * token, and not absorb the current token, even if it is a newline.
+         */
+        tokeniser.pushBack();
     }
 
     /**