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authorJędrzej Nowacki <jedrzej.nowacki@digia.com>2014-02-14 16:32:31 +0100
committerThe Qt Project <gerrit-noreply@qt-project.org>2014-05-16 09:51:38 +0200
commit71fb3633e8d909e9a91e1bee6eaf53c146f25998 (patch)
tree93995d7c6965b3cc944ed461dfcb4c5bbf5ac6f1 /src
parent8f3a393e412fccd6606af5ef8d909da6435e16e2 (diff)
Unify all mid() functions in QtBase.
Up to now, Qt had at least 3 different implementations of the mid(). Only QString::mid implementation was not crashing on edge cases and was protected against overflows, therefore I picked that one as the base implementation, even if it has weird semantics for an invalid input. As a side effect QVector::mid was slightly optimized to not detach in all cases (which follows current QList behavior). Documentation of QVector::mid and QList::mid was updated to not mention "copy of data" which could suggest that the mid() result is detached. QStringRef::mid was fixed and now it follows general Qt behavior, by returning a null value for a null input. Change-Id: Ie9ff5d98372bd193d66508e6dd92b6ed1180ad9b Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Diffstat (limited to 'src')
-rw-r--r--src/corelib/tools/qarraydata.cpp29
-rw-r--r--src/corelib/tools/qarraydata.h8
-rw-r--r--src/corelib/tools/qbytearray.cpp23
-rw-r--r--src/corelib/tools/qlist.cpp6
-rw-r--r--src/corelib/tools/qlist.h14
-rw-r--r--src/corelib/tools/qstring.cpp73
-rw-r--r--src/corelib/tools/qvector.cpp6
-rw-r--r--src/corelib/tools/qvector.h15
8 files changed, 114 insertions, 60 deletions
diff --git a/src/corelib/tools/qarraydata.cpp b/src/corelib/tools/qarraydata.cpp
index 2d744f97c0..4047bf611f 100644
--- a/src/corelib/tools/qarraydata.cpp
+++ b/src/corelib/tools/qarraydata.cpp
@@ -130,4 +130,33 @@ void QArrayData::deallocate(QArrayData *data, size_t objectSize,
::free(data);
}
+namespace QtPrivate {
+/*!
+ \internal
+*/
+QContainerImplHelper::CutResult QContainerImplHelper::mid(int originalLength, int *_position, int *_length)
+{
+ int &position = *_position;
+ int &length = *_length;
+ if (position > originalLength)
+ return Null;
+
+ if (position < 0) {
+ if (length < 0 || length + position >= originalLength)
+ return Full;
+ if (length + position <= 0)
+ return Null;
+ length += position;
+ position = 0;
+ } else if (uint(length) > uint(originalLength - position)) {
+ length = originalLength - position;
+ }
+
+ if (position == 0 && length == originalLength)
+ return Full;
+
+ return length > 0 ? Subset : Empty;
+}
+}
+
QT_END_NAMESPACE
diff --git a/src/corelib/tools/qarraydata.h b/src/corelib/tools/qarraydata.h
index 5a8c46b582..90503786e4 100644
--- a/src/corelib/tools/qarraydata.h
+++ b/src/corelib/tools/qarraydata.h
@@ -361,6 +361,14 @@ namespace QtPrivate {
QT_PREPEND_NAMESPACE(QtPrivate::qMakeArrayLiteral)<Type>( Array )
#endif // !defined(Q_ARRAY_LITERAL)
+namespace QtPrivate {
+struct Q_CORE_EXPORT QContainerImplHelper
+{
+ enum CutResult { Null, Empty, Full, Subset };
+ static CutResult mid(int originalLength, int *position, int *length);
+};
+}
+
QT_END_NAMESPACE
#endif // include guard
diff --git a/src/corelib/tools/qbytearray.cpp b/src/corelib/tools/qbytearray.cpp
index 9c2a242e8e..6fed3ae5c9 100644
--- a/src/corelib/tools/qbytearray.cpp
+++ b/src/corelib/tools/qbytearray.cpp
@@ -2677,19 +2677,22 @@ QByteArray QByteArray::right(int len) const
QByteArray QByteArray::mid(int pos, int len) const
{
- if ((d->size == 0 && d->ref.isStatic()) || pos > d->size)
+ using namespace QtPrivate;
+ switch (QContainerImplHelper::mid(size(), &pos, &len)) {
+ case QContainerImplHelper::Null:
return QByteArray();
- if (len < 0)
- len = d->size - pos;
- if (pos < 0) {
- len += pos;
- pos = 0;
+ case QContainerImplHelper::Empty:
+ {
+ QByteArrayDataPtr empty = { Data::allocate(0) };
+ return QByteArray(empty);
}
- if (len + pos > d->size)
- len = d->size - pos;
- if (pos == 0 && len == d->size)
+ case QContainerImplHelper::Full:
return *this;
- return QByteArray(d->data() + pos, len);
+ case QContainerImplHelper::Subset:
+ return QByteArray(d->data() + pos, len);
+ }
+ Q_UNREACHABLE();
+ return QByteArray();
}
/*!
diff --git a/src/corelib/tools/qlist.cpp b/src/corelib/tools/qlist.cpp
index 0811c3793e..db49fe9802 100644
--- a/src/corelib/tools/qlist.cpp
+++ b/src/corelib/tools/qlist.cpp
@@ -491,11 +491,11 @@ void **QListData::erase(void **xi)
/*!
\fn QList<T> QList<T>::mid(int pos, int length) const
- Returns a list whose elements are copied from this list,
+ Returns a sub-list which includes elements from this list,
starting at position \a pos. If \a length is -1 (the default), all
- elements from \a pos are copied; otherwise \a length elements (or
+ elements from \a pos are included; otherwise \a length elements (or
all remaining elements if there are less than \a length elements)
- are copied.
+ are included.
*/
/*! \fn QList::QList()
diff --git a/src/corelib/tools/qlist.h b/src/corelib/tools/qlist.h
index 9e4ba70908..4c52c22300 100644
--- a/src/corelib/tools/qlist.h
+++ b/src/corelib/tools/qlist.h
@@ -45,6 +45,7 @@
#include <QtCore/qalgorithms.h>
#include <QtCore/qiterator.h>
#include <QtCore/qrefcount.h>
+#include <QtCore/qarraydata.h>
#include <iterator>
#include <list>
@@ -646,10 +647,17 @@ inline void QList<T>::move(int from, int to)
template<typename T>
Q_OUTOFLINE_TEMPLATE QList<T> QList<T>::mid(int pos, int alength) const
{
- if (alength < 0 || pos > size() - alength)
- alength = size() - pos;
- if (pos == 0 && alength == size())
+ using namespace QtPrivate;
+ switch (QContainerImplHelper::mid(size(), &pos, &alength)) {
+ case QContainerImplHelper::Null:
+ case QContainerImplHelper::Empty:
+ return QList<T>();
+ case QContainerImplHelper::Full:
return *this;
+ case QContainerImplHelper::Subset:
+ break;
+ }
+
QList<T> cpy;
if (alength <= 0)
return cpy;
diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index aac9c493c3..541a853487 100644
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -4090,21 +4090,22 @@ QString QString::right(int n) const
QString QString::mid(int position, int n) const
{
- if (position > d->size)
+ using namespace QtPrivate;
+ switch (QContainerImplHelper::mid(d->size, &position, &n)) {
+ case QContainerImplHelper::Null:
return QString();
- if (position < 0) {
- if (n < 0 || n + position >= d->size)
- return *this;
- if (n + position <= 0)
- return QString();
-
- n += position;
- position = 0;
- } else if (uint(n) > uint(d->size - position))
- n = d->size - position;
- if (position == 0 && n == d->size)
+ case QContainerImplHelper::Empty:
+ {
+ QStringDataPtr empty = { Data::allocate(0) };
+ return QString(empty);
+ }
+ case QContainerImplHelper::Full:
return *this;
- return QString((const QChar*) d->data() + position, n);
+ case QContainerImplHelper::Subset:
+ return QString((const QChar*)d->data() + position, n);
+ }
+ Q_UNREACHABLE();
+ return QString();
}
/*!
@@ -8794,19 +8795,19 @@ QStringRef QString::rightRef(int n) const
*/
QStringRef QStringRef::mid(int pos, int n) const
{
- if (pos > m_size)
+ using namespace QtPrivate;
+ switch (QContainerImplHelper::mid(m_size, &pos, &n)) {
+ case QContainerImplHelper::Null:
return QStringRef();
- if (pos < 0) {
- if (n < 0 || n + pos >= m_size)
- return QStringRef(m_string, m_position, m_size);
- if (n + pos <= 0)
- return QStringRef();
- n += pos;
- pos = 0;
- } else if (uint(n) > uint(m_size - pos)) {
- n = m_size - pos;
+ case QContainerImplHelper::Empty:
+ return QStringRef(m_string, 0, 0);
+ case QContainerImplHelper::Full:
+ return *this;
+ case QContainerImplHelper::Subset:
+ return QStringRef(m_string, pos + m_position, n);
}
- return QStringRef(m_string, pos + m_position, n);
+ Q_UNREACHABLE();
+ return QStringRef();
}
/*!
@@ -8831,19 +8832,19 @@ QStringRef QStringRef::mid(int pos, int n) const
*/
QStringRef QString::midRef(int position, int n) const
{
- if (position > d->size)
+ using namespace QtPrivate;
+ switch (QContainerImplHelper::mid(d->size, &position, &n)) {
+ case QContainerImplHelper::Null:
return QStringRef();
- if (position < 0) {
- if (n < 0 || n + position >= d->size)
- return QStringRef(this, 0, d->size);
- if (n + position <= 0)
- return QStringRef();
-
- n += position;
- position = 0;
- } else if (uint(n) > uint(d->size - position))
- n = d->size - position;
- return QStringRef(this, position, n);
+ case QContainerImplHelper::Empty:
+ return QStringRef(this, 0, 0);
+ case QContainerImplHelper::Full:
+ return QStringRef(this, 0, d->size);
+ case QContainerImplHelper::Subset:
+ return QStringRef(this, position, n);
+ }
+ Q_UNREACHABLE();
+ return QStringRef();
}
/*!
diff --git a/src/corelib/tools/qvector.cpp b/src/corelib/tools/qvector.cpp
index b2b4315545..e1a451f953 100644
--- a/src/corelib/tools/qvector.cpp
+++ b/src/corelib/tools/qvector.cpp
@@ -180,11 +180,11 @@
/*!
\fn QVector<T> QVector::mid(int pos, int length = -1) const
- Returns a vector whose elements are copied from this vector,
+ Returns a sub-vector which contains elements from this vector,
starting at position \a pos. If \a length is -1 (the default), all
- elements after \a pos are copied; otherwise \a length elements (or
+ elements after \a pos are included; otherwise \a length elements (or
all remaining elements if there are less than \a length elements)
- are copied.
+ are included.
*/
diff --git a/src/corelib/tools/qvector.h b/src/corelib/tools/qvector.h
index 0a32c96958..9692477e18 100644
--- a/src/corelib/tools/qvector.h
+++ b/src/corelib/tools/qvector.h
@@ -822,12 +822,17 @@ int QVector<T>::count(const T &t) const
template <typename T>
Q_OUTOFLINE_TEMPLATE QVector<T> QVector<T>::mid(int pos, int len) const
{
- if (len < 0)
- len = size() - pos;
- if (pos == 0 && len == size())
+ using namespace QtPrivate;
+ switch (QContainerImplHelper::mid(d->size, &pos, &len)) {
+ case QContainerImplHelper::Null:
+ case QContainerImplHelper::Empty:
+ return QVector<T>();
+ case QContainerImplHelper::Full:
return *this;
- if (pos + len > size())
- len = size() - pos;
+ case QContainerImplHelper::Subset:
+ break;
+ }
+
QVector<T> copy;
copy.reserve(len);
for (int i = pos; i < pos + len; ++i)