From 9c0c998698ed5dbba38a4de74991ee620ffea5e8 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Wed, 20 Jul 2022 16:22:13 +0200
Subject: [PATCH] QStringIterator: fix UB [1/2]: use has{Next,Previous}() more

Replace

- pos > i with hasPrevious()
- pos < e with hasNext()

Everything is inline, so there's no difference in assembly, but less
source code lines to fix later.

Change-Id: I3f9cf2716c96b811b29b75fa20f88cc3b461771a
Reviewed-by: Mate Barany <mate.barany@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
(cherry picked from commit 34800d1f09447e921203561c0e4804c4f095136f)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/corelib/text/qstringiterator_p.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/corelib/text/qstringiterator_p.h b/src/corelib/text/qstringiterator_p.h
index 886b2047729..4665d738957 100644
--- a/src/corelib/text/qstringiterator_p.h
+++ b/src/corelib/text/qstringiterator_p.h
@@ -85,7 +85,7 @@ public:
         Q_ASSERT_X(hasNext(), Q_FUNC_INFO, "iterator hasn't a next item");
 
         if (Q_UNLIKELY((pos++)->isHighSurrogate())) {
-            Q_ASSERT(pos < e && pos->isLowSurrogate());
+            Q_ASSERT(hasNext() && pos->isLowSurrogate());
             ++pos;
         }
     }
@@ -124,7 +124,7 @@ public:
 
         const QChar cur = *pos++;
         if (Q_UNLIKELY(cur.isHighSurrogate())) {
-            Q_ASSERT(pos < e && pos->isLowSurrogate());
+            Q_ASSERT(hasNext() && pos->isLowSurrogate());
             return QChar::surrogateToUcs4(cur, *pos++);
         }
         return cur.unicode();
@@ -136,7 +136,7 @@ public:
 
         const QChar uc = *pos++;
         if (Q_UNLIKELY(uc.isSurrogate())) {
-            if (Q_LIKELY(uc.isHighSurrogate() && pos < e && pos->isLowSurrogate()))
+            if (Q_LIKELY(uc.isHighSurrogate() && hasNext() && pos->isLowSurrogate()))
                 return QChar::surrogateToUcs4(uc, *pos++);
             return invalidAs;
         }
@@ -167,7 +167,7 @@ public:
         Q_ASSERT_X(hasPrevious(), Q_FUNC_INFO, "iterator hasn't a previous item");
 
         if (Q_UNLIKELY((--pos)->isLowSurrogate())) {
-            Q_ASSERT(pos > i && pos[-1].isHighSurrogate());
+            Q_ASSERT(hasPrevious() && pos[-1].isHighSurrogate());
             --pos;
         }
     }
@@ -205,7 +205,7 @@ public:
 
         const QChar cur = *--pos;
         if (Q_UNLIKELY(cur.isLowSurrogate())) {
-            Q_ASSERT(pos > i && pos[-1].isHighSurrogate());
+            Q_ASSERT(hasPrevious() && pos[-1].isHighSurrogate());
             return QChar::surrogateToUcs4(*--pos, cur);
         }
         return cur.unicode();
@@ -217,7 +217,7 @@ public:
 
         const QChar uc = *--pos;
         if (Q_UNLIKELY(uc.isSurrogate())) {
-            if (Q_LIKELY(uc.isLowSurrogate() && pos > i && pos[-1].isHighSurrogate()))
+            if (Q_LIKELY(uc.isLowSurrogate() && hasPrevious() && pos[-1].isHighSurrogate()))
                 return QChar::surrogateToUcs4(*--pos, uc);
             return invalidAs;
         }