/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qvector.h"
#include "qtools_p.h"
#include <string.h>
QT_BEGIN_NAMESPACE
static inline int alignmentThreshold()
{
// malloc on 32-bit platforms should return pointers that are 8-byte aligned or more
// while on 64-bit platforms they should be 16-byte aligned or more
return 2 * sizeof(void*);
}
QVectorData QVectorData::shared_null = { Q_BASIC_ATOMIC_INITIALIZER(1), 0, 0, true, false, 0 };
QVectorData *QVectorData::malloc(int sizeofTypedData, int size, int sizeofT, QVectorData *init)
{
QVectorData* p = (QVectorData *)qMalloc(sizeofTypedData + (size - 1) * sizeofT);
Q_CHECK_PTR(p);
::memcpy(p, init, sizeofTypedData + (qMin(size, init->alloc) - 1) * sizeofT);
return p;
}
QVectorData *QVectorData::allocate(int size, int alignment)
{
return static_cast<QVectorData *>(alignment > alignmentThreshold() ? qMallocAligned(size, alignment) : qMalloc(size));
}
QVectorData *QVectorData::reallocate(QVectorData *x, int newsize, int oldsize, int alignment)
{
if (alignment > alignmentThreshold())
return static_cast<QVectorData *>(qReallocAligned(x, newsize, oldsize, alignment));
return static_cast<QVectorData *>(qRealloc(x, newsize));
}
void QVectorData::free(QVectorData *x, int alignment)
{
if (alignment > alignmentThreshold())
qFreeAligned(x);
else
qFree(x);
}
int QVectorData::grow(int sizeofTypedData, int size, int sizeofT, bool excessive)
{
if (excessive)
return size + size / 2;
return qAllocMore(size * sizeofT, sizeofTypedData - sizeofT) / sizeofT;
}
/*!
\class QVector
\brief The QVector class is a template class that provides a dynamic array.
\ingroup tools
\ingroup shared
\reentrant
QVector\<T\> is one of Qt's generic \l{container classes}. It
stores its items in adjacent memory locations and provides fast
index-based access.
QList\<T\>, QLinkedList\<T\>, and QVarLengthArray\<T\> provide
similar functionality. Here's an overview:
\list
\i For most purposes, QList is the right class to use. Operations
like prepend() and insert() are usually faster than with
QVector because of the way QList stores its items in memory
(see \l{Algorithmic Complexity} for details),
and its index-based API is more convenient than QLinkedList's
iterator-based API. It also expands to less code in your
executable.
\i If you need a real linked list, with guarantees of \l{constant
time} insertions in the middle of the list and iterators to
items rather than indexes, use QLinkedList.
\i If you want the items to occupy adjacent memory positions, or
if your items are larger than a pointer and you want to avoid
the overhead of allocating them on the heap individually at
insertion time, then use QVector.
\i If you want a low-level variable-size array, QVarLengthArray
may be sufficient.
\endlist
Here's an example of a QVector that stores integers and a QVector
that stores QString values:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 0
QVector stores a vector (or array) of items. Typically, vectors
are created with an initial size. For example, the following code
constructs a QVector with 200 elements:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 1
The elements are automatically initialized with a
\l{default-constructed value}. If you want to initialize the
vector with a different value, pass that value as the second
argument to the constructor:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 2
You can also call fill() at any time to fill the vector with a
value.
QVector uses 0-based indexes, just like C++ arrays. To access the
item at a particular index position, you can use operator[](). On
non-const vectors, operator[]() returns a reference to the item
that can be used on the left side of an assignment:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 3
For read-only access, an alternative syntax is to use at():
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 4
at() can be faster than operator[](), because it never causes a
\l{deep copy} to occur.
Another way to access the data stored in a QVector is to call
data(). The function returns a pointer to the first item in the
vector. You can use the pointer to directly access and modify the
elements stored in the vector. The pointer is also useful if you
need to pass a QVector to a function that accepts a plain C++
array.
If you want to find all occurrences of a particular value in a
vector, use indexOf() or lastIndexOf(). The former searches
forward starting from a given index position, the latter searches
backward. Both return the index of the matching item if they found
one; otherwise, they return -1. For example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 5
If you simply want to check whether a vector contains a
particular value, use contains(). If you want to find out how
many times a particular value occurs in the vector, use count().
QVector provides these basic functions to add, move, and remove
items: insert(), replace(), remove(), prepend(), append(). With
the exception of append() and replace(), these functions can be slow
(\l{linear time}) for large vectors, because they require moving many
items in the vector by one position in memory. If you want a container
class that provides fast insertion/removal in the middle, use
QList or QLinkedList instead.
Unlike plain C++ arrays, QVectors can be resized at any time by
calling resize(). If the new size is larger than the old size,
QVector might need to reallocate the whole vector. QVector tries
to reduce the number of reallocations by preallocating up to twice
as much memory as the actual data needs.
If you know in advance approximately how many items the QVector
will contain, you can call reserve(), asking QVector to
preallocate a certain amount of memory. You can also call
capacity() to find out how much memory QVector actually
allocated.
Note that using non-const operators and functions can cause
QVector to do a deep copy of the data. This is due to \l{implicit sharing}.
QVector's value type must be an \l{assignable data type}. This
covers most data types that are commonly used, but the compiler
won't let you, for example, store a QWidget as a value; instead,
store a QWidget *. A few functions have additional requirements;
for example, indexOf() and lastIndexOf() expect the value type to
support \c operator==(). These requirements are documented on a
per-function basis.
Like the other container classes, QVector provides \l{Java-style
iterators} (QVectorIterator and QMutableVectorIterator) and
\l{STL-style iterators} (QVector::const_iterator and
QVector::iterator). In practice, these are rarely used, because
you can use indexes into the QVector.
In addition to QVector, Qt also provides QVarLengthArray, a very
low-level class with little functionality that is optimized for
speed.
QVector does \e not support inserting, prepending, appending or replacing
with references to its own values. Doing so will cause your application to
abort with an error message.
\sa QVectorIterator, QMutableVectorIterator, QList, QLinkedList
*/
/*!
\fn QVector<T> QVector::mid(int pos, int length = -1) const
Returns a vector whose elements are copied 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
all remaining elements if there are less than \a length elements)
are copied.
*/
/*! \fn QVector::QVector()
Constructs an empty vector.
\sa resize()
*/
/*! \fn QVector::QVector(int size)
Constructs a vector with an initial size of \a size elements.
The elements are initialized with a \l{default-constructed
value}.
\sa resize()
*/
/*! \fn QVector::QVector(int size, const T &value)
Constructs a vector with an initial size of \a size elements.
Each element is initialized with \a value.
\sa resize(), fill()
*/
/*! \fn QVector::QVector(const QVector<T> &other)
Constructs a copy of \a other.
This operation takes \l{constant time}, because QVector is
\l{implicitly shared}. This makes returning a QVector from a
function very fast. If a shared instance is modified, it will be
copied (copy-on-write), and that takes \l{linear time}.
\sa operator=()
*/
/*! \fn QVector::~QVector()
Destroys the vector.
*/
/*! \fn QVector<T> &QVector::operator=(const QVector<T> &other)
Assigns \a other to this vector and returns a reference to this
vector.
*/
/*! \fn bool QVector::operator==(const QVector<T> &other) const
Returns true if \a other is equal to this vector; otherwise
returns false.
Two vectors are considered equal if they contain the same values
in the same order.
This function requires the value type to have an implementation
of \c operator==().
\sa operator!=()
*/
/*! \fn bool QVector::operator!=(const QVector<T> &other) const
Returns true if \a other is not equal to this vector; otherwise
returns false.
Two vectors are considered equal if they contain the same values
in the same order.
This function requires the value type to have an implementation
of \c operator==().
\sa operator==()
*/
/*! \fn int QVector::size() const
Returns the number of items in the vector.
\sa isEmpty(), resize()
*/
/*! \fn bool QVector::isEmpty() const
Returns true if the vector has size 0; otherwise returns false.
\sa size(), resize()
*/
/*! \fn void QVector::resize(int size)
Sets the size of the vector to \a size. If \a size is greater than the
current size, elements are added to the end; the new elements are
initialized with a \l{default-constructed value}. If \a size is less
than the current size, elements are removed from the end.
\sa size()
*/
/*! \fn int QVector::capacity() const
Returns the maximum number of items that can be stored in the
vector without forcing a reallocation.
The sole purpose of this function is to provide a means of fine
tuning QVector's memory usage. In general, you will rarely ever
need to call this function. If you want to know how many items are
in the vector, call size().
\sa reserve(), squeeze()
*/
/*! \fn void QVector::reserve(int size)
Attempts to allocate memory for at least \a size elements. If you
know in advance how large the vector will be, you can call this
function, and if you call resize() often you are likely to get
better performance. If \a size is an underestimate, the worst
that will happen is that the QVector will be a bit slower.
The sole purpose of this function is to provide a means of fine
tuning QVector's memory usage. In general, you will rarely ever
need to call this function. If you want to change the size of the
vector, call resize().
\sa squeeze(), capacity()
*/
/*! \fn void QVector::squeeze()
Releases any memory not required to store the items.
The sole purpose of this function is to provide a means of fine
tuning QVector's memory usage. In general, you will rarely ever
need to call this function.
\sa reserve(), capacity()
*/
/*! \fn void QVector::detach()
\internal
*/
/*! \fn bool QVector::isDetached() const
\internal
*/
/*! \fn void QVector::setSharable(bool sharable)
\internal
*/
/*! \fn T *QVector::data()
Returns a pointer to the data stored in the vector. The pointer
can be used to access and modify the items in the vector.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 6
The pointer remains valid as long as the vector isn't
reallocated.
This function is mostly useful to pass a vector to a function
that accepts a plain C++ array.
\sa constData(), operator[]()
*/
/*! \fn const T *QVector::data() const
\overload
*/
/*! \fn const T *QVector::constData() const
Returns a const pointer to the data stored in the vector. The
pointer can be used to access the items in the vector.
The pointer remains valid as long as the vector isn't
reallocated.
This function is mostly useful to pass a vector to a function
that accepts a plain C++ array.
\sa data(), operator[]()
*/
/*! \fn void QVector::clear()
Removes all the elements from the vector and releases the memory used by
the vector.
*/
/*! \fn const T &QVector::at(int i) const
Returns the item at index position \a i in the vector.
\a i must be a valid index position in the vector (i.e., 0 <= \a
i < size()).
\sa value(), operator[]()
*/
/*! \fn T &QVector::operator[](int i)
Returns the item at index position \a i as a modifiable reference.
\a i must be a valid index position in the vector (i.e., 0 <= \a i
< size()).
Note that using non-const operators can cause QVector to do a deep
copy.
\sa at(), value()
*/
/*! \fn const T &QVector::operator[](int i) const
\overload
Same as at(\a i).
*/
/*!
\fn void QVector::append(const T &value)
Inserts \a value at the end of the vector.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 7
This is the same as calling resize(size() + 1) and assigning \a
value to the new last element in the vector.
This operation is relatively fast, because QVector typically
allocates more memory than necessary, so it can grow without
reallocating the entire vector each time.
\sa operator<<(), prepend(), insert()
*/
/*! \fn void QVector::prepend(const T &value)
Inserts \a value at the beginning of the vector.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 8
This is the same as vector.insert(0, \a value).
For large vectors, this operation can be slow (\l{linear time}),
because it requires moving all the items in the vector by one
position further in memory. If you want a container class that
provides a fast prepend() function, use QList or QLinkedList
instead.
\sa append(), insert()
*/
/*! \fn void QVector::insert(int i, const T &value)
Inserts \a value at index position \a i in the vector. If \a i is
0, the value is prepended to the vector. If \a i is size(), the
value is appended to the vector.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 9
For large vectors, this operation can be slow (\l{linear time}),
because it requires moving all the items at indexes \a i and
above by one position further in memory. If you want a container
class that provides a fast insert() function, use QLinkedList
instead.
\sa append(), prepend(), remove()
*/
/*! \fn void QVector::insert(int i, int count, const T &value)
\overload
Inserts \a count copies of \a value at index position \a i in the
vector.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 10
*/
/*! \fn QVector::iterator QVector::insert(iterator before, const T &value)
\overload
Inserts \a value in front of the item pointed to by the iterator
\a before. Returns an iterator pointing at the inserted item.
*/
/*! \fn QVector::iterator QVector::insert(iterator before, int count, const T &value)
Inserts \a count copies of \a value in front of the item pointed to
by the iterator \a before. Returns an iterator pointing at the
first of the inserted items.
*/
/*! \fn void QVector::replace(int i, const T &value)
Replaces the item at index position \a i with \a value.
\a i must be a valid index position in the vector (i.e., 0 <= \a
i < size()).
\sa operator[](), remove()
*/
/*! \fn void QVector::remove(int i)
\overload
Removes the element at index position \a i.
\sa insert(), replace(), fill()
*/
/*! \fn void QVector::remove(int i, int count)
\overload
Removes \a count elements from the middle of the vector, starting at
index position \a i.
\sa insert(), replace(), fill()
*/
/*! \fn QVector &QVector::fill(const T &value, int size = -1)
Assigns \a value to all items in the vector. If \a size is
different from -1 (the default), the vector is resized to size \a
size beforehand.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 11
\sa resize()
*/
/*! \fn int QVector::indexOf(const T &value, int from = 0) const
Returns the index position of the first occurrence of \a value in
the vector, searching forward from index position \a from.
Returns -1 if no item matched.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 12
This function requires the value type to have an implementation of
\c operator==().
\sa lastIndexOf(), contains()
*/
/*! \fn int QVector::lastIndexOf(const T &value, int from = -1) const
Returns the index position of the last occurrence of the value \a
value in the vector, searching backward from index position \a
from. If \a from is -1 (the default), the search starts at the
last item. Returns -1 if no item matched.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 13
This function requires the value type to have an implementation of
\c operator==().
\sa indexOf()
*/
/*! \fn bool QVector::contains(const T &value) const
Returns true if the vector contains an occurrence of \a value;
otherwise returns false.
This function requires the value type to have an implementation of
\c operator==().
\sa indexOf(), count()
*/
/*! \fn bool QVector::startsWith(const T &value) const
\since 4.5
Returns true if this vector is not empty and its first
item is equal to \a value; otherwise returns false.
\sa isEmpty(), first()
*/
/*! \fn bool QVector::endsWith(const T &value) const
\since 4.5
Returns true if this vector is not empty and its last
item is equal to \a value; otherwise returns false.
\sa isEmpty(), last()
*/
/*! \fn int QVector::count(const T &value) const
Returns the number of occurrences of \a value in the vector.
This function requires the value type to have an implementation of
\c operator==().
\sa contains(), indexOf()
*/
/*! \fn int QVector::count() const
\overload
Same as size().
*/
/*! \fn QVector::iterator QVector::begin()
Returns an \l{STL-style iterator} pointing to the first item in
the vector.
\sa constBegin(), end()
*/
/*! \fn QVector::const_iterator QVector::begin() const
\overload
*/
/*! \fn QVector::const_iterator QVector::constBegin() const
Returns a const \l{STL-style iterator} pointing to the first item
in the vector.
\sa begin(), constEnd()
*/
/*! \fn QVector::iterator QVector::end()
Returns an \l{STL-style iterator} pointing to the imaginary item
after the last item in the vector.
\sa begin(), constEnd()
*/
/*! \fn QVector::const_iterator QVector::end() const
\overload
*/
/*! \fn QVector::const_iterator QVector::constEnd() const
Returns a const \l{STL-style iterator} pointing to the imaginary
item after the last item in the vector.
\sa constBegin(), end()
*/
/*! \fn QVector::iterator QVector::erase(iterator pos)
Removes the item pointed to by the iterator \a pos from the
vector, and returns an iterator to the next item in the vector
(which may be end()).
\sa insert(), remove()
*/
/*! \fn QVector::iterator QVector::erase(iterator begin, iterator end)
\overload
Removes all the items from \a begin up to (but not including) \a
end. Returns an iterator to the same item that \a end referred to
before the call.
*/
/*! \fn T& QVector::first()
Returns a reference to the first item in the vector. This
function assumes that the vector isn't empty.
\sa last(), isEmpty()
*/
/*! \fn const T& QVector::first() const
\overload
*/
/*! \fn T& QVector::last()
Returns a reference to the last item in the vector. This function
assumes that the vector isn't empty.
\sa first(), isEmpty()
*/
/*! \fn const T& QVector::last() const
\overload
*/
/*! \fn T QVector::value(int i) const
Returns the value at index position \a i in the vector.
If the index \a i is out of bounds, the function returns
a \l{default-constructed value}. If you are certain that
\a i is within bounds, you can use at() instead, which is slightly
faster.
\sa at(), operator[]()
*/
/*! \fn T QVector::value(int i, const T &defaultValue) const
\overload
If the index \a i is out of bounds, the function returns
\a defaultValue.
*/
/*! \fn void QVector::push_back(const T &value)
This function is provided for STL compatibility. It is equivalent
to append(\a value).
*/
/*! \fn void QVector::push_front(const T &value)
This function is provided for STL compatibility. It is equivalent
to prepend(\a value).
*/
/*! \fn void QVector::pop_front()
This function is provided for STL compatibility. It is equivalent
to erase(begin()).
*/
/*! \fn void QVector::pop_back()
This function is provided for STL compatibility. It is equivalent
to erase(end() - 1).
*/
/*! \fn T& QVector::front()
This function is provided for STL compatibility. It is equivalent
to first().
*/
/*! \fn QVector::const_reference QVector::front() const
\overload
*/
/*! \fn QVector::reference QVector::back()
This function is provided for STL compatibility. It is equivalent
to last().
*/
/*! \fn QVector::const_reference QVector::back() const
\overload
*/
/*! \fn bool QVector::empty() const
This function is provided for STL compatibility. It is equivalent
to isEmpty(), returning true if the vector is empty; otherwise
returns false.
*/
/*! \fn QVector<T> &QVector::operator+=(const QVector<T> &other)
Appends the items of the \a other vector to this vector and
returns a reference to this vector.
\sa operator+(), append()
*/
/*! \fn void QVector::operator+=(const T &value)
\overload
Appends \a value to the vector.
\sa append(), operator<<()
*/
/*! \fn QVector<T> QVector::operator+(const QVector<T> &other) const
Returns a vector that contains all the items in this vector
followed by all the items in the \a other vector.
\sa operator+=()
*/
/*! \fn QVector<T> &QVector::operator<<(const T &value)
Appends \a value to the vector and returns a reference to this
vector.
\sa append(), operator+=()
*/
/*! \fn QVector<T> &QVector::operator<<(const QVector<T> &other)
Appends \a other to the vector and returns a reference to the
vector.
*/
/*! \typedef QVector::iterator
The QVector::iterator typedef provides an STL-style non-const
iterator for QVector and QStack.
QVector provides both \l{STL-style iterators} and \l{Java-style
iterators}. The STL-style non-const iterator is simply a typedef
for "T *" (pointer to T).
\sa QVector::begin(), QVector::end(), QVector::const_iterator, QMutableVectorIterator
*/
/*! \typedef QVector::const_iterator
The QVector::const_iterator typedef provides an STL-style const
iterator for QVector and QStack.
QVector provides both \l{STL-style iterators} and \l{Java-style
iterators}. The STL-style const iterator is simply a typedef for
"const T *" (pointer to const T).
\sa QVector::constBegin(), QVector::constEnd(), QVector::iterator, QVectorIterator
*/
/*! \typedef QVector::Iterator
Qt-style synonym for QVector::iterator.
*/
/*! \typedef QVector::ConstIterator
Qt-style synonym for QVector::const_iterator.
*/
/*! \typedef QVector::const_pointer
Typedef for const T *. Provided for STL compatibility.
*/
/*! \typedef QVector::const_reference
Typedef for T &. Provided for STL compatibility.
*/
/*! \typedef QVector::difference_type
Typedef for ptrdiff_t. Provided for STL compatibility.
*/
/*! \typedef QVector::pointer
Typedef for T *. Provided for STL compatibility.
*/
/*! \typedef QVector::reference
Typedef for T &. Provided for STL compatibility.
*/
/*! \typedef QVector::size_type
Typedef for int. Provided for STL compatibility.
*/
/*! \typedef QVector::value_type
Typedef for T. Provided for STL compatibility.
*/
/*! \fn QList<T> QVector<T>::toList() const
Returns a QList object with the data contained in this QVector.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 14
\sa fromList(), QList::fromVector()
*/
/*! \fn QVector<T> QVector<T>::fromList(const QList<T> &list)
Returns a QVector object with the data contained in \a list.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 15
\sa toList(), QList::toVector()
*/
/*! \fn QVector<T> QVector<T>::fromStdVector(const std::vector<T> &vector)
Returns a QVector object with the data contained in \a vector. The
order of the elements in the QVector is the same as in \a vector.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 16
\sa toStdVector(), QList::fromStdList()
*/
/*! \fn std::vector<T> QVector<T>::toStdVector() const
Returns a std::vector object with the data contained in this QVector.
Example:
\snippet doc/src/snippets/code/src_corelib_tools_qvector.cpp 17
\sa fromStdVector(), QList::toStdList()
*/
/*! \fn QDataStream &operator<<(QDataStream &out, const QVector<T> &vector)
\relates QVector
Writes the vector \a vector to stream \a out.
This function requires the value type to implement \c operator<<().
\sa \link datastreamformat.html Format of the QDataStream operators \endlink
*/
/*! \fn QDataStream &operator>>(QDataStream &in, QVector<T> &vector)
\relates QVector
Reads a vector from stream \a in into \a vector.
This function requires the value type to implement \c operator>>().
\sa \link datastreamformat.html Format of the QDataStream operators \endlink
*/
QT_END_NAMESPACE