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+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:FDL$
+** 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 Free Documentation License
+** Alternatively, this file may be used under the terms of the GNU Free
+** Documentation License version 1.3 as published by the Free Software
+** Foundation and appearing in the file included in the packaging of this
+** file.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+ \class QVarLengthArray
+ \brief The QVarLengthArray class provides a low-level variable-length array.
+
+ \ingroup tools
+ \reentrant
+
+ The C++ language doesn't support variable-length arrays on the stack.
+ For example, the following code won't compile:
+
+ \snippet doc/src/snippets/code/doc_src_qvarlengtharray.cpp 0
+
+ The alternative is to allocate the array on the heap (with
+ \c{new}):
+
+ \snippet doc/src/snippets/code/doc_src_qvarlengtharray.cpp 1
+
+ However, if myfunc() is called very frequently from the
+ application's inner loop, heap allocation can be a major source
+ of slowdown.
+
+ QVarLengthArray is an attempt to work around this gap in the C++
+ language. It allocates a certain number of elements on the stack,
+ and if you resize the array to a larger size, it automatically
+ uses the heap instead. Stack allocation has the advantage that
+ it is much faster than heap allocation.
+
+ Example:
+ \snippet doc/src/snippets/code/doc_src_qvarlengtharray.cpp 2
+
+ In the example above, QVarLengthArray will preallocate 1024
+ elements on the stack and use them unless \c{n + 1} is greater
+ than 1024. If you omit the second template argument,
+ QVarLengthArray's default of 256 is used.
+
+ QVarLengthArray'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 *.
+
+ QVarLengthArray, like QVector, provides a resizable array data
+ structure. The main differences between the two classes are:
+
+ \list
+ \o QVarLengthArray's API is much more low-level. It provides no
+ iterators and lacks much of QVector's functionality.
+
+ \o QVarLengthArray doesn't initialize the memory if the value is
+ a basic type. (QVector always does.)
+
+ \o QVector uses \l{implicit sharing} as a memory optimization.
+ QVarLengthArray doesn't provide that feature; however, it
+ usually produces slightly better performance due to reduced
+ overhead, especially in tight loops.
+ \endlist
+
+ In summary, QVarLengthArray is a low-level optimization class
+ that only makes sense in very specific cases. It is used a few
+ places inside Qt and was added to Qt's public API for the
+ convenience of advanced users.
+
+ \sa QVector, QList, QLinkedList
+*/
+
+/*! \fn QVarLengthArray::QVarLengthArray(int size)
+
+ Constructs an array with an initial size of \a size elements.
+
+ If the value type is a primitive type (e.g., char, int, float) or
+ a pointer type (e.g., QWidget *), the elements are not
+ initialized. For other types, the elements are initialized with a
+ \l{default-constructed value}.
+*/
+
+/*! \fn QVarLengthArray::~QVarLengthArray()
+
+ Destroys the array.
+*/
+
+/*! \fn int QVarLengthArray::size() const
+
+ Returns the number of elements in the array.
+
+ \sa isEmpty(), resize()
+*/
+
+/*! \fn int QVarLengthArray::count() const
+
+ Same as size().
+
+ \sa isEmpty(), resize()
+*/
+
+/*! \fn bool QVarLengthArray::isEmpty() const
+
+ Returns true if the array has size 0; otherwise returns false.
+
+ \sa size(), resize()
+*/
+
+/*! \fn void QVarLengthArray::clear()
+
+ Removes all the elements from the array.
+
+ Same as resize(0).
+*/
+
+/*! \fn void QVarLengthArray::resize(int size)
+
+ Sets the size of the array to \a size. If \a size is greater than
+ the current size, elements are added to the end. If \a size is
+ less than the current size, elements are removed from the end.
+
+ If the value type is a primitive type (e.g., char, int, float) or
+ a pointer type (e.g., QWidget *), new elements are not
+ initialized. For other types, the elements are initialized with a
+ \l{default-constructed value}.
+
+ \sa size()
+*/
+
+/*! \fn int QVarLengthArray::capacity() const
+
+ Returns the maximum number of elements that can be stored in the
+ array without forcing a reallocation.
+
+ The sole purpose of this function is to provide a means of fine
+ tuning QVarLengthArray'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 array, call size().
+
+ \sa reserve()
+*/
+
+/*! \fn void QVarLengthArray::reserve(int size)
+
+ Attempts to allocate memory for at least \a size elements. If you
+ know in advance how large the array can get, 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 QVarLengthArray will be a bit
+ slower.
+
+ The sole purpose of this function is to provide a means of fine
+ tuning QVarLengthArray's memory usage. In general, you will
+ rarely ever need to call this function. If you want to change the
+ size of the array, call resize().
+
+ \sa capacity()
+*/
+
+/*! \fn T &QVarLengthArray::operator[](int i)
+
+ Returns a reference to the item at index position \a i.
+
+ \a i must be a valid index position in the array (i.e., 0 <= \a i
+ < size()).
+
+ \sa data(), at()
+*/
+
+/*! \fn const T &QVarLengthArray::operator[](int i) const
+
+ \overload
+*/
+
+
+/*!
+ \fn void QVarLengthArray::append(const T &t)
+
+ Appends item \a t to the array, extending the array if necessary.
+
+ \sa removeLast()
+*/
+
+
+/*!
+ \fn inline void QVarLengthArray::removeLast()
+ \since 4.5
+
+ Decreases the size of the array by one. The allocated size is not changed.
+
+ \sa append()
+*/
+
+/*!
+ \fn void QVarLengthArray::append(const T *buf, int size)
+
+ Appends \a size amount of items referenced by \a buf to this array.
+*/
+
+
+/*! \fn T *QVarLengthArray::data()
+
+ Returns a pointer to the data stored in the array. The pointer can
+ be used to access and modify the items in the array.
+
+ Example:
+ \snippet doc/src/snippets/code/doc_src_qvarlengtharray.cpp 3
+
+ The pointer remains valid as long as the array isn't reallocated.
+
+ This function is mostly useful to pass an array to a function
+ that accepts a plain C++ array.
+
+ \sa constData(), operator[]()
+*/
+
+/*! \fn const T *QVarLengthArray::data() const
+
+ \overload
+*/
+
+/*! \fn const T *QVarLengthArray::constData() const
+
+ Returns a const pointer to the data stored in the array. The
+ pointer can be used to access the items in the array. The
+ pointer remains valid as long as the array isn't reallocated.
+
+ This function is mostly useful to pass an array to a function
+ that accepts a plain C++ array.
+
+ \sa data(), operator[]()
+*/
+
+/*! \fn QVarLengthArray<T, Prealloc> &QVarLengthArray::operator=(const QVarLengthArray<T, Prealloc> &other)
+ Assigns \a other to this array and returns a reference to this array.
+ */
+
+/*! \fn QVarLengthArray::QVarLengthArray(const QVarLengthArray<T, Prealloc> &other)
+ Constructs a copy of \a other.
+ */
+
+/*! \fn const T &QVarLengthArray::at(int i) const
+
+ Returns a reference to the item at index position \a i.
+
+ \a i must be a valid index position in the array (i.e., 0 <= \a i
+ < size()).
+
+ \sa value(), operator[]()
+*/
+
+/*! \fn T QVarLengthArray::value(int i) const
+
+ Returns the value at index position \a i.
+
+ 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 QVarLengthArray::value(int i, const T &defaultValue) const
+
+ \overload
+
+ If the index \a i is out of bounds, the function returns
+ \a defaultValue.
+*/
+
+/*!
+ \typedef QVarLengthArray::size_type
+ \since 4.7
+
+ Typedef for int. Provided for STL compatibility.
+*/
+
+/*!
+ \typedef QVarLengthArray::value_type
+ \since 4.7
+
+ Typedef for T. Provided for STL compatibility.
+*/
+
+/*!
+ \typedef QVarLengthArray::difference_type
+ \since 4.7
+
+ Typedef for ptrdiff_t. Provided for STL compatibility.
+*/
+
+/*!
+ \typedef QVarLengthArray::pointer
+ \since 4.7
+
+ Typedef for T *. Provided for STL compatibility.
+*/
+
+/*!
+ \typedef QVarLengthArray::const_pointer
+ \since 4.7
+
+ Typedef for const T *. Provided for STL compatibility.
+*/
+
+/*!
+ \typedef QVarLengthArray::reference
+ \since 4.7
+
+ Typedef for T &. Provided for STL compatibility.
+*/
+
+/*!
+ \typedef QVarLengthArray::const_reference
+ \since 4.7
+
+ Typedef for const T &. Provided for STL compatibility.
+*/
+
+/*! \fn void QVarLengthArray::prepend(const T &value)
+
+ \since 4.8
+ Inserts \a value at the beginning of the array.
+
+
+ This is the same as vector.insert(0, \a value).
+
+ For large arrays, 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 QVarLengthArray::replace(int i, const T &value)
+
+ \since 4.8
+ Replaces the item at index position \a i with \a value.
+
+ \a i must be a valid index position in the array (i.e., 0 <= \a
+ i < size()).
+
+ \sa operator[](), remove()
+*/
+
+/*! \fn void QVarLengthArray::remove(int i)
+
+ \overload
+ \since 4.8
+
+ Removes the element at index position \a i.
+
+ \sa insert(), replace()
+*/
+
+/*! \fn void QVarLengthArray::remove(int i, int count)
+
+ \overload
+ \since 4.8
+
+ Removes \a count elements from the middle of the array, starting at
+ index position \a i.
+
+ \sa insert(), replace()
+*/
+
+/*! \fn QVarLengthArray::iterator QVarLengthArray::begin()
+ \since 4.8
+
+ Returns an \l{STL-style iterator} pointing to the first item in
+ the array.
+
+ \sa constBegin(), end()
+*/
+
+/*! \fn QVarLengthArray::const_iterator QVarLengthArray::begin() const
+ \since 4.8
+ \overload
+*/
+
+/*! \fn QVarLengthArray::const_iterator QVarLengthArray::constBegin() const
+ \since 4.8
+
+ Returns a const \l{STL-style iterator} pointing to the first item
+ in the array.
+
+ \sa begin(), constEnd()
+*/
+
+/*! \fn QVarLengthArray::iterator QVarLengthArray::end()
+ \since 4.8
+
+ Returns an \l{STL-style iterator} pointing to the imaginary item
+ after the last item in the array.
+
+ \sa begin(), constEnd()
+*/
+
+/*! \fn QVarLengthArray::const_iterator QVarLengthArray::end() const
+ \since 4.8
+
+ \overload
+*/
+
+/*! \fn QVarLengthArray::const_iterator QVarLengthArray::constEnd() const
+ \since 4.8
+
+ Returns a const \l{STL-style iterator} pointing to the imaginary
+ item after the last item in the array.
+
+ \sa constBegin(), end()
+*/
+
+/*! \fn QVarLengthArray::iterator QVarLengthArray::erase(iterator pos)
+ \since 4.8
+
+ 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 QVarLengthArray::iterator QVarLengthArray::erase(iterator begin, iterator end)
+
+ \overload
+ \since 4.8
+
+ 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 void QVarLengthArray::insert(int i, const T &value)
+ \since 4.8
+
+ Inserts \a value at index position \a i in the array. If \a i is
+ 0, the value is prepended to the vector. If \a i is size(), the
+ value is appended to the vector.
+
+ For large arrays, 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 remove()
+*/
+
+/*! \fn void QVarLengthArray::insert(int i, int count, const T &value)
+
+ \overload
+ \since 4.8
+
+ Inserts \a count copies of \a value at index position \a i in the
+ vector.
+*/
+
+/*! \fn QVarLengthArray::iterator QVarLengthArray::insert(iterator before, const T &value)
+
+ \overload
+ \since 4.8
+
+ Inserts \a value in front of the item pointed to by the iterator
+ \a before. Returns an iterator pointing at the inserted item.
+*/
+
+/*! \fn QVarLengthArray::iterator QVarLengthArray::insert(iterator before, int count, const T &value)
+
+ \since 4.8
+ 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 bool operator==(const QVarLengthArray<T, Prealloc1> &left, const QVarLengthArray<T, Prealloc2> &right)
+
+ \relates QVarLengthArray
+ \since 4.8
+ Returns true if the two array are equal;
+
+ Two arrays 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 operator!=(const QVarLengthArray<T, Prealloc1> &left, const QVarLengthArray<T, Prealloc2> &right)
+
+ \relates QVarLengthArray
+ \since 4.8
+ Returns true if the two array are different;
+
+ Two arrays 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 QVarLengthArray &QVarLengthArray::operator<<(const T &value)
+
+ \since 4.8
+ Appends \a value to the array and returns a reference to this
+ vector.
+
+ \sa append(), operator+=()
+*/
+
+/*! \fn QVarLengthArray &QVarLengthArray::operator+=(const T &value)
+
+ \since 4.8
+ Appends \a value to the array and returns a reference to this
+ vector.
+
+ \sa append(), operator<<()
+*/
+