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authorJason Barron <jbarron@trolltech.com>2009-06-25 13:49:53 (GMT)
committerJason Barron <jbarron@trolltech.com>2009-06-25 13:49:53 (GMT)
commitdb8f05e257019694f5e8076845626008f2adc3dd (patch)
tree05d3959403cf15ac5f702091439e028af01f343b /src/corelib/tools/qstring.cpp
parent8aafaa65a1d16f8b982279f5aceedf1e281ddb5a (diff)
parent796a5a2c7d8c91a46ac761dde18b7da2ec6c177b (diff)
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Merge commit 'qt/master-stable' into 4.6-stable
Bring Qt 4.6 into the Qt-S60 repo. Conflicts: configure.exe mkspecs/features/qttest_p4.prf qmake/generators/makefile.cpp src/corelib/io/qdir.cpp src/corelib/io/qprocess.h src/corelib/kernel/qcoreevent.h src/corelib/kernel/qobject.cpp src/corelib/kernel/qsharedmemory_unix.cpp src/corelib/thread/qthread_p.h src/corelib/tools/qvector.h src/gui/dialogs/qdialog.cpp src/gui/dialogs/qfiledialog.cpp src/gui/dialogs/qfiledialog_p.h src/gui/dialogs/qmessagebox.cpp src/gui/graphicsview/qgraphicsitem.cpp src/gui/graphicsview/qgraphicsview.cpp src/gui/image/qpixmapcache.cpp src/gui/kernel/qapplication.cpp src/gui/kernel/qapplication_p.h src/gui/kernel/qwidget.cpp src/gui/kernel/qwidget_p.h src/gui/painting/qdrawhelper.cpp src/gui/painting/qpaintengine_raster.cpp src/gui/text/qfontengine_qpf.cpp src/gui/widgets/qmenubar.cpp src/network/socket/qlocalserver.cpp src/testlib/qtestcase.cpp src/testlib/testlib.pro tests/auto/qimagereader/tst_qimagereader.cpp tests/auto/qitemdelegate/tst_qitemdelegate.cpp tests/auto/qnetworkreply/tst_qnetworkreply.cpp tests/auto/qpixmap/qpixmap.pro
Diffstat (limited to 'src/corelib/tools/qstring.cpp')
-rw-r--r--src/corelib/tools/qstring.cpp95
1 files changed, 89 insertions, 6 deletions
diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index e61a568..6ae3c38 100644
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -195,6 +195,68 @@ static int ucstrnicmp(const ushort *a, const ushort *b, int l)
return ucstricmp(a, a + l, b, b + l);
}
+static bool qMemEquals(const quint16 *a, const quint16 *b, int length)
+{
+ // Benchmarking indicates that doing memcmp is much slower than
+ // executing the comparison ourselves.
+ // To make it even faster, we do a 32-bit comparison, comparing
+ // twice the amount of data as a normal word-by-word comparison.
+ //
+ // Benchmarking results on a 2.33 GHz Core2 Duo, with a 64-QChar
+ // block of data, with 4194304 iterations (per iteration):
+ // operation usec cpu ticks
+ // memcmp 330 710
+ // 16-bit 79 167-171
+ // 32-bit aligned 49 105-109
+ //
+ // Testing also indicates that unaligned 32-bit loads are as
+ // performant as 32-bit aligned.
+ if (a == b || !length)
+ return true;
+
+ register union {
+ const quint16 *w;
+ const quint32 *d;
+ quintptr value;
+ } sa, sb;
+ sa.w = a;
+ sb.w = b;
+
+ // check alignment
+ if ((sa.value & 2) == (sb.value & 2)) {
+ // both addresses have the same alignment
+ if (sa.value & 2) {
+ // both addresses are not aligned to 4-bytes boundaries
+ // compare the first character
+ if (*sa.w != *sb.w)
+ return false;
+ --length;
+ ++sa.w;
+ ++sb.w;
+
+ // now both addresses are 4-bytes aligned
+ }
+
+ // both addresses are 4-bytes aligned
+ // do a fast 32-bit comparison
+ register const quint32 *e = sa.d + (length >> 1);
+ for ( ; sa.d != e; ++sa.d, ++sb.d) {
+ if (*sa.d != *sb.d)
+ return false;
+ }
+
+ // do we have a tail?
+ return (length & 1) ? *sa.w == *sb.w : true;
+ } else {
+ // one of the addresses isn't 4-byte aligned but the other is
+ register const quint16 *e = sa.w + length;
+ for ( ; sa.w != e; ++sa.w, ++sb.w) {
+ if (*sa.w != *sb.w)
+ return false;
+ }
+ }
+ return true;
+}
/*!
\internal
@@ -884,6 +946,23 @@ QString::QString(int size, QChar ch)
}
}
+/*!
+ Constructs a string of the given \a size without initializing the
+ characters. This is only used in \c QStringBuilder::toString().
+
+ \internal
+*/
+
+QString::QString(int size, Uninitialized)
+{
+ d = (Data*) qMalloc(sizeof(Data)+size*sizeof(QChar));
+ d->ref = 1;
+ d->alloc = d->size = size;
+ d->clean = d->asciiCache = d->simpletext = d->righttoleft = d->capacity = 0;
+ d->data = d->array;
+ d->array[size] = '\0';
+}
+
/*! \fn QString::QString(const QLatin1String &str)
Constructs a copy of the Latin-1 string \a str.
@@ -1910,8 +1989,10 @@ QString &QString::replace(QChar c, const QLatin1String &after, Qt::CaseSensitivi
*/
bool QString::operator==(const QString &other) const
{
- return (size() == other.size()) &&
- (memcmp((char*)unicode(),(char*)other.unicode(), size()*sizeof(QChar))==0);
+ if (d->size != other.d->size)
+ return false;
+
+ return qMemEquals(d->data, other.d->data, d->size);
}
/*!
@@ -3138,7 +3219,7 @@ bool QString::startsWith(const QString& s, Qt::CaseSensitivity cs) const
if (s.d->size > d->size)
return false;
if (cs == Qt::CaseSensitive) {
- return memcmp((char*)d->data, (char*)s.d->data, s.d->size*sizeof(QChar)) == 0;
+ return qMemEquals(d->data, s.d->data, s.d->size);
} else {
uint last = 0;
uint olast = 0;
@@ -3209,7 +3290,7 @@ bool QString::endsWith(const QString& s, Qt::CaseSensitivity cs) const
if (pos < 0)
return false;
if (cs == Qt::CaseSensitive) {
- return memcmp((char*)&d->data[pos], (char*)s.d->data, s.d->size*sizeof(QChar)) == 0;
+ return qMemEquals(d->data + pos, s.d->data, s.d->size);
} else {
uint last = 0;
uint olast = 0;
@@ -7696,7 +7777,8 @@ QString QStringRef::toString() const {
*/
bool operator==(const QStringRef &s1,const QStringRef &s2)
{ return (s1.size() == s2.size() &&
- (memcmp((char*)s1.unicode(), (char*)s2.unicode(), s1.size()*sizeof(QChar))==0)); }
+ qMemEquals((const ushort *)s1.unicode(), (const ushort *)s2.unicode(), s1.size()));
+}
/*! \relates QStringRef
@@ -7705,7 +7787,8 @@ bool operator==(const QStringRef &s1,const QStringRef &s2)
*/
bool operator==(const QString &s1,const QStringRef &s2)
{ return (s1.size() == s2.size() &&
- (memcmp((char*)s1.unicode(), (char*)s2.unicode(), s1.size()*sizeof(QChar))==0)); }
+ qMemEquals((const ushort *)s1.unicode(), (const ushort *)s2.unicode(), s1.size()));
+}
/*! \relates QStringRef