From 9d68ddd2ce4bb1625b4a7bc06d85f2b61361d960 Mon Sep 17 00:00:00 2001
From: "scc%mozilla.org" <scc%mozilla.org@18797224-902f-48f8-a5cc-f745e15eee43>
Date: Thu, 31 Aug 2000 06:12:35 +0000
Subject: [PATCH] make |Last| not try to adjust an iterator into an empty
 string (stops illegal calls to |Last| on an empty string from going into an
 infinite looop), r=mscott

git-svn-id: svn://10.0.0.236/trunk@77752 18797224-902f-48f8-a5cc-f745e15eee43
---
 mozilla/string/public/nsAReadableString.h       | 7 ++++++-
 mozilla/xpcom/ds/nsAReadableString.h            | 7 ++++++-
 mozilla/xpcom/string/public/nsAReadableString.h | 7 ++++++-
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/mozilla/string/public/nsAReadableString.h b/mozilla/string/public/nsAReadableString.h
index f0862e8db6a..888574e0d5d 100644
--- a/mozilla/string/public/nsAReadableString.h
+++ b/mozilla/string/public/nsAReadableString.h
@@ -571,7 +571,12 @@ basic_nsAReadableString<CharT>::Last() const
   {
     NS_ASSERTION(Length()>0, "|Last()| on an empty string");
 
-    return *(EndReading()-=1);
+    // nsReadingIterator<CharT> iter; EndReading(iter);
+    nsReadingIterator<CharT> iter( EndReading() );
+    if ( !IsEmpty() )
+      iter -= 1;
+
+    return *iter; // Note: this has undefined results if |IsEmpty()|
   }
 
 template <class CharT>
diff --git a/mozilla/xpcom/ds/nsAReadableString.h b/mozilla/xpcom/ds/nsAReadableString.h
index f0862e8db6a..888574e0d5d 100644
--- a/mozilla/xpcom/ds/nsAReadableString.h
+++ b/mozilla/xpcom/ds/nsAReadableString.h
@@ -571,7 +571,12 @@ basic_nsAReadableString<CharT>::Last() const
   {
     NS_ASSERTION(Length()>0, "|Last()| on an empty string");
 
-    return *(EndReading()-=1);
+    // nsReadingIterator<CharT> iter; EndReading(iter);
+    nsReadingIterator<CharT> iter( EndReading() );
+    if ( !IsEmpty() )
+      iter -= 1;
+
+    return *iter; // Note: this has undefined results if |IsEmpty()|
   }
 
 template <class CharT>
diff --git a/mozilla/xpcom/string/public/nsAReadableString.h b/mozilla/xpcom/string/public/nsAReadableString.h
index f0862e8db6a..888574e0d5d 100644
--- a/mozilla/xpcom/string/public/nsAReadableString.h
+++ b/mozilla/xpcom/string/public/nsAReadableString.h
@@ -571,7 +571,12 @@ basic_nsAReadableString<CharT>::Last() const
   {
     NS_ASSERTION(Length()>0, "|Last()| on an empty string");
 
-    return *(EndReading()-=1);
+    // nsReadingIterator<CharT> iter; EndReading(iter);
+    nsReadingIterator<CharT> iter( EndReading() );
+    if ( !IsEmpty() )
+      iter -= 1;
+
+    return *iter; // Note: this has undefined results if |IsEmpty()|
   }
 
 template <class CharT>