From 5e01d3f64265867284e6bba8d1881e10c5d7605c Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@kdab.com>
Date: Wed, 1 Oct 2014 10:10:29 +0200
Subject: [PATCH] QList: iterate forward in count()/contains()

After much head-scratching, we found no reason for the backwards iteration.
Indeed, forward iteration should be slightly faster than backwards, because
it operates in the direction in which cache-lines are filled, usually.

This is in preparation of using std algorithms instead of hand-written
loops. It avoids having to use std::reverse_iterator.

Change-Id: Ib62cf0a6f2a33d186cb174b23b0d6bb2891b6c63
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/tools/qlist.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/corelib/tools/qlist.h b/src/corelib/tools/qlist.h
index b56afe15c2..9704c7b953 100644
--- a/src/corelib/tools/qlist.h
+++ b/src/corelib/tools/qlist.h
@@ -921,9 +921,9 @@ Q_OUTOFLINE_TEMPLATE int QList<T>::lastIndexOf(const T &t, int from) const
 template <typename T>
 Q_OUTOFLINE_TEMPLATE bool QList<T>::contains(const T &t) const
 {
-    Node *b = reinterpret_cast<Node *>(p.begin());
-    Node *i = reinterpret_cast<Node *>(p.end());
-    while (i-- != b)
+    Node *e = reinterpret_cast<Node *>(p.end());
+    Node *i = reinterpret_cast<Node *>(p.begin());
+    for (; i != e; ++i)
         if (i->t() == t)
             return true;
     return false;
@@ -933,9 +933,9 @@ template <typename T>
 Q_OUTOFLINE_TEMPLATE int QList<T>::count(const T &t) const
 {
     int c = 0;
-    Node *b = reinterpret_cast<Node *>(p.begin());
-    Node *i = reinterpret_cast<Node *>(p.end());
-    while (i-- != b)
+    Node *e = reinterpret_cast<Node *>(p.end());
+    Node *i = reinterpret_cast<Node *>(p.begin());
+    for (; i != e; ++i)
         if (i->t() == t)
             ++c;
     return c;