/**************************************************************************** ** ** 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 #include "qlist.h" #include "qtools_p.h" #include QT_BEGIN_NAMESPACE /* QList as an array-list combines the easy-of-use of a random access interface with fast list operations and the low memory management overhead of an array. Accessing elements by index, appending, prepending, and removing elements from both the front and the back all happen in constant time O(1). Inserting or removing elements at random index positions \ai happens in linear time, or more precisly in O(min{i,n-i}) <= O(n/2), with n being the number of elements in the list. */ QListData::Data QListData::shared_null = { Q_BASIC_ATOMIC_INITIALIZER(1), 0, 0, 0, true, { 0 } }; static int grow(int size) { // dear compiler: don't optimize me out. volatile int x = qAllocMore(size * sizeof(void *), QListData::DataHeaderSize) / sizeof(void *); return x; } /*! * Detaches the QListData by allocating new memory for a list which will be bigger * than the copied one and is expected to grow further. * *idx is the desired insertion point and is clamped to the actual size of the list. * num is the number of new elements to insert at the insertion point. * Returns the old (shared) data, it is up to the caller to deref() and free(). * For the new data node_copy needs to be called. * * \internal */ QListData::Data *QListData::detach_grow(int *idx, int num) { Data *x = d; int l = x->end - x->begin; int nl = l + num; int alloc = grow(nl); Data* t = static_cast(qMalloc(DataHeaderSize + alloc * sizeof(void *))); Q_CHECK_PTR(t); t->ref = 1; t->sharable = true; t->alloc = alloc; // The space reservation algorithm's optimization is biased towards appending: // Something which looks like an append will put the data at the beginning, // while something which looks like a prepend will put it in the middle // instead of at the end. That's based on the assumption that prepending // is uncommon and even an initial prepend will eventually be followed by // at least some appends. int bg; if (*idx < 0) { *idx = 0; bg = (alloc - nl) >> 1; } else if (*idx > l) { *idx = l; bg = 0; } else if (*idx < (l >> 1)) { bg = (alloc - nl) >> 1; } else { bg = 0; } t->begin = bg; t->end = bg + nl; d = t; return x; } #if QT_VERSION >= 0x050000 # error "Remove QListData::detach(), it is only required for binary compatibility for 4.0.x to 4.2.x" #endif QListData::Data *QListData::detach() { Data *x = static_cast(qMalloc(DataHeaderSize + d->alloc * sizeof(void *))); Q_CHECK_PTR(x); x->ref = 1; x->sharable = true; x->alloc = d->alloc; if (!x->alloc) { x->begin = 0; x->end = 0; } else { x->begin = d->begin; x->end = d->end; } qSwap(d, x); if (!x->ref.deref()) return x; return 0; } /*! * Detaches the QListData by reallocating new memory. * Returns the old (shared) data, it is up to the caller to deref() and free() * For the new data node_copy needs to be called. * * \internal */ #if QT_VERSION >= 0x050000 # error "Remove QListData::detach2(), it is only required for binary compatibility for 4.3.x to 4.5.x" #endif QListData::Data *QListData::detach2() { Data *x = d; Data* t = static_cast(qMalloc(DataHeaderSize + x->alloc * sizeof(void *))); Q_CHECK_PTR(t); ::memcpy(t, d, DataHeaderSize + d->alloc * sizeof(void *)); t->ref = 1; t->sharable = true; t->alloc = x->alloc; if (!t->alloc) { t->begin = 0; t->end = 0; } else { t->begin = x->begin; t->end = x->end; } d = t; return x; } /*! * Detaches the QListData by allocating new memory for a list which possibly * has a different size than the copied one. * Returns the old (shared) data, it is up to the caller to deref() and free() * For the new data node_copy needs to be called. * * \internal */ QListData::Data *QListData::detach(int alloc) { Data *x = d; Data* t = static_cast(qMalloc(DataHeaderSize + alloc * sizeof(void *))); Q_CHECK_PTR(t); t->ref = 1; t->sharable = true; t->alloc = alloc; if (!alloc) { t->begin = 0; t->end = 0; } else { t->begin = x->begin; t->end = x->end; } d = t; return x; } /*! * Detaches the QListData by reallocating new memory. * Returns the old (shared) data, it is up to the caller to deref() and free() * For the new data node_copy needs to be called. * * \internal */ #if QT_VERSION >= 0x050000 # error "Remove QListData::detach3(), it is only required for binary compatibility for 4.5.x to 4.6.x" #endif QListData::Data *QListData::detach3() { return detach(d->alloc); } void QListData::realloc(int alloc) { Q_ASSERT(d->ref == 1); Data *x = static_cast(qRealloc(d, DataHeaderSize + alloc * sizeof(void *))); Q_CHECK_PTR(x); d = x; d->alloc = alloc; if (!alloc) d->begin = d->end = 0; } // ensures that enough space is available to append n elements void **QListData::append(int n) { Q_ASSERT(d->ref == 1); int e = d->end; if (e + n > d->alloc) { int b = d->begin; if (b - n >= 2 * d->alloc / 3) { // we have enough space. Just not at the end -> move it. e -= b; ::memcpy(d->array, d->array + b, e * sizeof(void *)); d->begin = 0; } else { realloc(grow(d->alloc + n)); } } d->end = e + n; return d->array + e; } // ensures that enough space is available to append one element void **QListData::append() { return append(1); } // ensures that enough space is available to append the list #if QT_VERSION >= 0x050000 # error "Remove QListData::append(), it is only required for binary compatibility up to 4.5.x" #endif void **QListData::append(const QListData& l) { Q_ASSERT(d->ref == 1); int e = d->end; int n = l.d->end - l.d->begin; if (n) { if (e + n > d->alloc) realloc(grow(e + n)); ::memcpy(d->array + d->end, l.d->array + l.d->begin, n*sizeof(void*)); d->end += n; } return d->array + e; } // ensures that enough space is available to append the list void **QListData::append2(const QListData& l) { return append(l.d->end - l.d->begin); } void **QListData::prepend() { Q_ASSERT(d->ref == 1); if (d->begin == 0) { if (d->end >= d->alloc / 3) realloc(grow(d->alloc + 1)); if (d->end < d->alloc / 3) d->begin = d->alloc - 2 * d->end; else d->begin = d->alloc - d->end; ::memmove(d->array + d->begin, d->array, d->end * sizeof(void *)); d->end += d->begin; } return d->array + --d->begin; } void **QListData::insert(int i) { Q_ASSERT(d->ref == 1); if (i <= 0) return prepend(); int size = d->end - d->begin; if (i >= size) return append(); bool leftward = false; if (d->begin == 0) { if (d->end == d->alloc) { // If the array is full, we expand it and move some items rightward realloc(grow(d->alloc + 1)); } else { // If there is free space at the end of the array, we move some items rightward } } else { if (d->end == d->alloc) { // If there is free space at the beginning of the array, we move some items leftward leftward = true; } else { // If there is free space at both ends, we move as few items as possible leftward = (i < size - i); } } if (leftward) { --d->begin; ::memmove(d->array + d->begin, d->array + d->begin + 1, i * sizeof(void *)); } else { ::memmove(d->array + d->begin + i + 1, d->array + d->begin + i, (size - i) * sizeof(void *)); ++d->end; } return d->array + d->begin + i; } void QListData::remove(int i) { Q_ASSERT(d->ref == 1); i += d->begin; if (i - d->begin < d->end - i) { if (int offset = i - d->begin) ::memmove(d->array + d->begin + 1, d->array + d->begin, offset * sizeof(void *)); d->begin++; } else { if (int offset = d->end - i - 1) ::memmove(d->array + i, d->array + i + 1, offset * sizeof(void *)); d->end--; } } void QListData::remove(int i, int n) { Q_ASSERT(d->ref == 1); i += d->begin; int middle = i + n/2; if (middle - d->begin < d->end - middle) { ::memmove(d->array + d->begin + n, d->array + d->begin, (i - d->begin) * sizeof(void*)); d->begin += n; } else { ::memmove(d->array + i, d->array + i + n, (d->end - i - n) * sizeof(void*)); d->end -= n; } } void QListData::move(int from, int to) { Q_ASSERT(d->ref == 1); if (from == to) return; from += d->begin; to += d->begin; void *t = d->array[from]; if (from < to) { if (d->end == d->alloc || 3 * (to - from) < 2 * (d->end - d->begin)) { ::memmove(d->array + from, d->array + from + 1, (to - from) * sizeof(void *)); } else { // optimization if (int offset = from - d->begin) ::memmove(d->array + d->begin + 1, d->array + d->begin, offset * sizeof(void *)); if (int offset = d->end - (to + 1)) ::memmove(d->array + to + 2, d->array + to + 1, offset * sizeof(void *)); ++d->begin; ++d->end; ++to; } } else { if (d->begin == 0 || 3 * (from - to) < 2 * (d->end - d->begin)) { ::memmove(d->array + to + 1, d->array + to, (from - to) * sizeof(void *)); } else { // optimization if (int offset = to - d->begin) ::memmove(d->array + d->begin - 1, d->array + d->begin, offset * sizeof(void *)); if (int offset = d->end - (from + 1)) ::memmove(d->array + from, d->array + from + 1, offset * sizeof(void *)); --d->begin; --d->end; --to; } } d->array[to] = t; } void **QListData::erase(void **xi) { Q_ASSERT(d->ref == 1); int i = xi - (d->array + d->begin); remove(i); return d->array + d->begin + i; } /*! \class QList \brief The QList class is a template class that provides lists. \ingroup tools \ingroup shared \reentrant QList\ is one of Qt's generic \l{container classes}. It stores a list of values and provides fast index-based access as well as fast insertions and removals. QList\, QLinkedList\, and QVector\ provide similar functionality. Here's an overview: \list \i For most purposes, QList is the right class to use. Its index-based API is more convenient than QLinkedList's iterator-based API, and it is usually faster than QVector because of the way it stores its items in memory. 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, use QVector. \endlist Internally, QList\ is represented as an array of pointers to items of type T. If T is itself a pointer type or a basic type that is no larger than a pointer, or if T is one of Qt's \l{shared classes}, then QList\ stores the items directly in the pointer array. For lists under a thousand items, this array representation allows for very fast insertions in the middle, and it allows index-based access. Furthermore, operations like prepend() and append() are very fast, because QList preallocates memory at both ends of its internal array. (See \l{Algorithmic Complexity} for details.) Note, however, that for unshared list items that are larger than a pointer, each append or insert of a new item requires allocating the new item on the heap, and this per item allocation might make QVector a better choice in cases that do lots of appending or inserting, since QVector allocates memory for its items in a single heap allocation. Note that the internal array only ever gets bigger over the life of the list. It never shrinks. The internal array is deallocated by the destructor and by the assignment operator, when one list is assigned to another. Here's an example of a QList that stores integers and a QList that stores QDate values: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 0 Qt includes a QStringList class that inherits QList\ and adds a few convenience functions, such as QStringList::join() and QStringList::find(). (QString::split() creates QStringLists from strings.) QList stores a list of items. The default constructor creates an empty list. To insert items into the list, you can use operator<<(): \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 1 QList provides these basic functions to add, move, and remove items: insert(), replace(), removeAt(), move(), and swap(). In addition, it provides the following convenience functions: append(), prepend(), removeFirst(), and removeLast(). QList uses 0-based indexes, just like C++ arrays. To access the item at a particular index position, you can use operator[](). On non-const lists, operator[]() returns a reference to the item and can be used on the left side of an assignment: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 2 Because QList is implemented as an array of pointers, this operation is very fast (\l{constant time}). For read-only access, an alternative syntax is to use at(): \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 3 at() can be faster than operator[](), because it never causes a \l{deep copy} to occur. A common requirement is to remove an item from a list and do something with it. For this, QList provides takeAt(), takeFirst(), and takeLast(). Here's a loop that removes the items from a list one at a time and calls \c delete on them: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 4 Inserting and removing items at either ends of the list is very fast (\l{constant time} in most cases), because QList preallocates extra space on both sides of its internal buffer to allow for fast growth at both ends of the list. If you want to find all occurrences of a particular value in a list, use indexOf() or lastIndexOf(). The former searches forward starting from a given index position, the latter searches backward. Both return the index of a matching item if they find it; otherwise, they return -1. For example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 5 If you simply want to check whether a list contains a particular value, use contains(). If you want to find out how many times a particular value occurs in the list, use count(). If you want to replace all occurrences of a particular value with another, use replace(). QList'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, QList provides \l{Java-style iterators} (QListIterator and QMutableListIterator) and \l{STL-style iterators} (QList::const_iterator and QList::iterator). In practice, these are rarely used, because you can use indexes into the QList. QList is implemented in such a way that direct index-based access is just as fast as using iterators. QList 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. To make QList as efficient as possible, its member functions don't validate their input before using it. Except for isEmpty(), member functions always assume the list is \e not empty. Member functions that take index values as parameters always assume their index value parameters are in the valid range. This means QList member functions can fail. If you define QT_NO_DEBUG when you compile, failures will not be detected. If you \e don't define QT_NO_DEBUG, failures will be detected using Q_ASSERT() or Q_ASSERT_X() with an appropriate message. To avoid failures when your list can be empty, call isEmpty() before calling other member functions. If you must pass an index value that might not be in the valid range, check that it is less than the value returned by size() but \e not less than 0. \sa QListIterator, QMutableListIterator, QLinkedList, QVector */ /*! \fn QList QList::mid(int pos, int length) const Returns a list whose elements are copied 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 all remaining elements if there are less than \a length elements) are copied. */ /*! \fn QList::QList() Constructs an empty list. */ /*! \fn QList::QList(const QList &other) Constructs a copy of \a other. This operation takes \l{constant time}, because QList is \l{implicitly shared}. This makes returning a QList 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 QList::~QList() Destroys the list. References to the values in the list and all iterators of this list become invalid. */ /*! \fn QList &QList::operator=(const QList &other) Assigns \a other to this list and returns a reference to this list. */ /*! \fn bool QList::operator==(const QList &other) const Returns true if \a other is equal to this list; otherwise returns false. Two lists 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 QList::operator!=(const QList &other) const Returns true if \a other is not equal to this list; otherwise returns false. Two lists 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 QList::size() const Returns the number of items in the list. \sa isEmpty(), count() */ /*! \fn void QList::detach() \internal */ /*! \fn void QList::detachShared() \internal like detach(), but does nothing if we're shared_null. This prevents needless mallocs, and makes QList more exception safe in case of cleanup work done in destructors on empty lists. */ /*! \fn bool QList::isDetached() const \internal */ /*! \fn void QList::setSharable(bool sharable) \internal */ /*! \fn bool QList::isSharedWith(const QList &other) const \internal */ /*! \fn bool QList::isEmpty() const Returns true if the list contains no items; otherwise returns false. \sa size() */ /*! \fn void QList::clear() Removes all items from the list. \sa removeAll() */ /*! \fn const T &QList::at(int i) const Returns the item at index position \a i in the list. \a i must be a valid index position in the list (i.e., 0 <= \a i < size()). This function is very fast (\l{constant time}). \sa value(), operator[]() */ /*! \fn T &QList::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 list (i.e., 0 <= \a i < size()). This function is very fast (\l{constant time}). \sa at(), value() */ /*! \fn const T &QList::operator[](int i) const \overload Same as at(). */ /*! \fn QList::reserve(int alloc) Reserve space for \a alloc elements. If \a alloc is smaller than the current size of the list, nothing will happen. Use this function to avoid repetetive reallocation of QList's internal data if you can predict how many elements will be appended. Note that the reservation applies only to the internal pointer array. \since 4.7 */ /*! \fn void QList::append(const T &value) Inserts \a value at the end of the list. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 6 This is the same as list.insert(size(), \a value). This operation is typically very fast (\l{constant time}), because QList preallocates extra space on both sides of its internal buffer to allow for fast growth at both ends of the list. \sa operator<<(), prepend(), insert() */ /*! \fn void QList::append(const QList &value) \overload \since 4.5 Appends the items of the \a value list to this list. \sa operator<<(), operator+=() */ /*! \fn void QList::prepend(const T &value) Inserts \a value at the beginning of the list. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 7 This is the same as list.insert(0, \a value). This operation is usually very fast (\l{constant time}), because QList preallocates extra space on both sides of its internal buffer to allow for fast growth at both ends of the list. \sa append(), insert() */ /*! \fn void QList::insert(int i, const T &value) Inserts \a value at index position \a i in the list. If \a i is 0, the value is prepended to the list. If \a i is size(), the value is appended to the list. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 8 \sa append(), prepend(), replace(), removeAt() */ /*! \fn QList::iterator QList::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. Note that the iterator passed to the function will be invalid after the call; the returned iterator should be used instead. */ /*! \fn void QList::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 list (i.e., 0 <= \a i < size()). \sa operator[](), removeAt() */ /*! \fn int QList::removeAll(const T &value) Removes all occurrences of \a value in the list and returns the number of entries removed. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 9 This function requires the value type to have an implementation of \c operator==(). \sa removeOne(), removeAt(), takeAt(), replace() */ /*! \fn bool QList::removeOne(const T &value) \since 4.4 Removes the first occurrence of \a value in the list and returns true on success; otherwise returns false. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 10 This function requires the value type to have an implementation of \c operator==(). \sa removeAll(), removeAt(), takeAt(), replace() */ /*! \fn void QList::removeAt(int i) Removes the item at index position \a i. \a i must be a valid index position in the list (i.e., 0 <= \a i < size()). \sa takeAt(), removeFirst(), removeLast(), removeOne() */ /*! \fn T QList::takeAt(int i) Removes the item at index position \a i and returns it. \a i must be a valid index position in the list (i.e., 0 <= \a i < size()). If you don't use the return value, removeAt() is more efficient. \sa removeAt(), takeFirst(), takeLast() */ /*! \fn T QList::takeFirst() Removes the first item in the list and returns it. This is the same as takeAt(0). This function assumes the list is not empty. To avoid failure, call isEmpty() before calling this function. This operation is very fast (\l{constant time}), because QList preallocates extra space on both sides of its internal buffer to allow for fast growth at both ends of the list. If you don't use the return value, removeFirst() is more efficient. \sa takeLast(), takeAt(), removeFirst() */ /*! \fn T QList::takeLast() Removes the last item in the list and returns it. This is the same as takeAt(size() - 1). This function assumes the list is not empty. To avoid failure, call isEmpty() before calling this function. This operation is very fast (\l{constant time}), because QList preallocates extra space on both sides of its internal buffer to allow for fast growth at both ends of the list. If you don't use the return value, removeLast() is more efficient. \sa takeFirst(), takeAt(), removeLast() */ /*! \fn void QList::move(int from, int to) Moves the item at index position \a from to index position \a to. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 11 This is the same as insert(\a{to}, takeAt(\a{from})).This function assumes that both \a from and \a to are at least 0 but less than size(). To avoid failure, test that both \a from and \a to are at least 0 and less than size(). \sa swap(), insert(), takeAt() */ /*! \fn void QList::swap(int i, int j) Exchange the item at index position \a i with the item at index position \a j. This function assumes that both \a i and \a j are at least 0 but less than size(). To avoid failure, test that both \a i and \a j are at least 0 and less than size(). Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 12 \sa move() */ /*! \fn int QList::indexOf(const T &value, int from = 0) const Returns the index position of the first occurrence of \a value in the list, searching forward from index position \a from. Returns -1 if no item matched. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 13 This function requires the value type to have an implementation of \c operator==(). Note that QList uses 0-based indexes, just like C++ arrays. Negative indexes are not supported with the exception of the value mentioned above. \sa lastIndexOf(), contains() */ /*! \fn int QList::lastIndexOf(const T &value, int from = -1) const Returns the index position of the last occurrence of \a value in the list, 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_qlistdata.cpp 14 This function requires the value type to have an implementation of \c operator==(). Note that QList uses 0-based indexes, just like C++ arrays. Negative indexes are not supported with the exception of the value mentioned above. \sa indexOf() */ /*! \fn QBool QList::contains(const T &value) const Returns true if the list 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 int QList::count(const T &value) const Returns the number of occurrences of \a value in the list. This function requires the value type to have an implementation of \c operator==(). \sa contains(), indexOf() */ /*! \fn bool QList::startsWith(const T &value) const \since 4.5 Returns true if this list is not empty and its first item is equal to \a value; otherwise returns false. \sa isEmpty(), contains() */ /*! \fn bool QList::endsWith(const T &value) const \since 4.5 Returns true if this list is not empty and its last item is equal to \a value; otherwise returns false. \sa isEmpty(), contains() */ /*! \fn QList::iterator QList::begin() Returns an \l{STL-style iterator} pointing to the first item in the list. \sa constBegin(), end() */ /*! \fn QList::const_iterator QList::begin() const \overload */ /*! \fn QList::const_iterator QList::constBegin() const Returns a const \l{STL-style iterator} pointing to the first item in the list. \sa begin(), constEnd() */ /*! \fn QList::iterator QList::end() Returns an \l{STL-style iterator} pointing to the imaginary item after the last item in the list. \sa begin(), constEnd() */ /*! \fn const_iterator QList::end() const \overload */ /*! \fn QList::const_iterator QList::constEnd() const Returns a const \l{STL-style iterator} pointing to the imaginary item after the last item in the list. \sa constBegin(), end() */ /*! \fn QList::iterator QList::erase(iterator pos) Removes the item associated with the iterator \a pos from the list, and returns an iterator to the next item in the list (which may be end()). \sa insert(), removeAt() */ /*! \fn QList::iterator QList::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. */ /*! \typedef QList::Iterator Qt-style synonym for QList::iterator. */ /*! \typedef QList::ConstIterator Qt-style synonym for QList::const_iterator. */ /*! \typedef QList::size_type Typedef for int. Provided for STL compatibility. */ /*! \typedef QList::value_type Typedef for T. Provided for STL compatibility. */ /*! \typedef QList::difference_type Typedef for ptrdiff_t. Provided for STL compatibility. */ /*! \typedef QList::pointer Typedef for T *. Provided for STL compatibility. */ /*! \typedef QList::const_pointer Typedef for const T *. Provided for STL compatibility. */ /*! \typedef QList::reference Typedef for T &. Provided for STL compatibility. */ /*! \typedef QList::const_reference Typedef for const T &. Provided for STL compatibility. */ /*! \fn int QList::count() const Returns the number of items in the list. This is effectively the same as size(). */ /*! \fn int QList::length() const \since 4.5 This function is identical to count(). \sa count() */ /*! \fn T& QList::first() Returns a reference to the first item in the list. The list must not be empty. If the list can be empty, call isEmpty() before calling this function. \sa last(), isEmpty() */ /*! \fn const T& QList::first() const \overload */ /*! \fn T& QList::last() Returns a reference to the last item in the list. The list must not be empty. If the list can be empty, call isEmpty() before calling this function. \sa first(), isEmpty() */ /*! \fn const T& QList::last() const \overload */ /*! \fn void QList::removeFirst() Removes the first item in the list. Calling this function is equivalent to calling removeAt(0). The list must not be empty. If the list can be empty, call isEmpty() before calling this function. \sa removeAt(), takeFirst() */ /*! \fn void QList::removeLast() Removes the last item in the list. Calling this function is equivalent to calling removeAt(size() - 1). The list must not be empty. If the list can be empty, call isEmpty() before calling this function. \sa removeAt(), takeLast() */ /*! \fn T QList::value(int i) const Returns the value at index position \a i in the list. If the index \a i is out of bounds, the function returns a \l{default-constructed value}. If you are certain that the index is going to be within bounds, you can use at() instead, which is slightly faster. \sa at(), operator[]() */ /*! \fn T QList::value(int i, const T &defaultValue) const \overload If the index \a i is out of bounds, the function returns \a defaultValue. */ /*! \fn void QList::push_back(const T &value) This function is provided for STL compatibility. It is equivalent to \l{QList::append()}{append(\a value)}. */ /*! \fn void QList::push_front(const T &value) This function is provided for STL compatibility. It is equivalent to \l{QList::prepend()}{prepend(\a value)}. */ /*! \fn T& QList::front() This function is provided for STL compatibility. It is equivalent to first(). The list must not be empty. If the list can be empty, call isEmpty() before calling this function. */ /*! \fn const T& QList::front() const \overload */ /*! \fn T& QList::back() This function is provided for STL compatibility. It is equivalent to last(). The list must not be empty. If the list can be empty, call isEmpty() before calling this function. */ /*! \fn const T& QList::back() const \overload */ /*! \fn void QList::pop_front() This function is provided for STL compatibility. It is equivalent to removeFirst(). The list must not be empty. If the list can be empty, call isEmpty() before calling this function. */ /*! \fn void QList::pop_back() This function is provided for STL compatibility. It is equivalent to removeLast(). The list must not be empty. If the list can be empty, call isEmpty() before calling this function. */ /*! \fn bool QList::empty() const This function is provided for STL compatibility. It is equivalent to isEmpty() and returns true if the list is empty. */ /*! \fn QList &QList::operator+=(const QList &other) Appends the items of the \a other list to this list and returns a reference to this list. \sa operator+(), append() */ /*! \fn void QList::operator+=(const T &value) \overload Appends \a value to the list. \sa append(), operator<<() */ /*! \fn QList QList::operator+(const QList &other) const Returns a list that contains all the items in this list followed by all the items in the \a other list. \sa operator+=() */ /*! \fn QList &QList::operator<<(const QList &other) Appends the items of the \a other list to this list and returns a reference to this list. \sa operator+=(), append() */ /*! \fn void QList::operator<<(const T &value) \overload Appends \a value to the list. */ /*! \class QList::iterator \brief The QList::iterator class provides an STL-style non-const iterator for QList and QQueue. QList features both \l{STL-style iterators} and \l{Java-style iterators}. The STL-style iterators are more low-level and more cumbersome to use; on the other hand, they are slightly faster and, for developers who already know STL, have the advantage of familiarity. QList\::iterator allows you to iterate over a QList\ (or QQueue\) and to modify the list item associated with the iterator. If you want to iterate over a const QList, use QList::const_iterator instead. It is generally good practice to use QList::const_iterator on a non-const QList as well, unless you need to change the QList through the iterator. Const iterators are slightly faster, and can improve code readability. The default QList::iterator constructor creates an uninitialized iterator. You must initialize it using a QList function like QList::begin(), QList::end(), or QList::insert() before you can start iterating. Here's a typical loop that prints all the items stored in a list: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 15 Let's see a few examples of things we can do with a QList::iterator that we cannot do with a QList::const_iterator. Here's an example that increments every value stored in a QList\ by 2: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 16 Most QList functions accept an integer index rather than an iterator. For that reason, iterators are rarely useful in connection with QList. One place where STL-style iterators do make sense is as arguments to \l{generic algorithms}. For example, here's how to delete all the widgets stored in a QList\: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 17 Multiple iterators can be used on the same list. However, be aware that any non-const function call performed on the QList will render all existing iterators undefined. If you need to keep iterators over a long period of time, we recommend that you use QLinkedList rather than QList. \sa QList::const_iterator, QMutableListIterator */ /*! \typedef QList::iterator::iterator_category A synonym for \e {std::random_access_iterator_tag} indicating this iterator is a random access iterator. */ /*! \typedef QList::iterator::difference_type \internal */ /*! \typedef QList::iterator::value_type \internal */ /*! \typedef QList::iterator::pointer \internal */ /*! \typedef QList::iterator::reference \internal */ /*! \fn QList::iterator::iterator() Constructs an uninitialized iterator. Functions like operator*() and operator++() should not be called on an uninitialized iterator. Use operator=() to assign a value to it before using it. \sa QList::begin() QList::end() */ /*! \fn QList::iterator::iterator(Node *node) \internal */ /*! \fn QList::iterator::iterator(const iterator &other) Constructs a copy of \a other. */ /*! \fn T &QList::iterator::operator*() const Returns a modifiable reference to the current item. You can change the value of an item by using operator*() on the left side of an assignment, for example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 18 \sa operator->() */ /*! \fn T *QList::iterator::operator->() const Returns a pointer to the current item. \sa operator*() */ /*! \fn T &QList::iterator::operator[](int j) const Returns a modifiable reference to the item at position *this + \a{j}. This function is provided to make QList iterators behave like C++ pointers. \sa operator+() */ /*! \fn bool QList::iterator::operator==(const iterator &other) const \fn bool QList::iterator::operator==(const const_iterator &other) const Returns true if \a other points to the same item as this iterator; otherwise returns false. \sa operator!=() */ /*! \fn bool QList::iterator::operator!=(const iterator &other) const \fn bool QList::iterator::operator!=(const const_iterator &other) const Returns true if \a other points to a different item than this iterator; otherwise returns false. \sa operator==() */ /*! \fn bool QList::iterator::operator<(const iterator& other) const \fn bool QList::iterator::operator<(const const_iterator& other) const Returns true if the item pointed to by this iterator is less than the item pointed to by the \a other iterator. */ /*! \fn bool QList::iterator::operator<=(const iterator& other) const \fn bool QList::iterator::operator<=(const const_iterator& other) const Returns true if the item pointed to by this iterator is less than or equal to the item pointed to by the \a other iterator. */ /*! \fn bool QList::iterator::operator>(const iterator& other) const \fn bool QList::iterator::operator>(const const_iterator& other) const Returns true if the item pointed to by this iterator is greater than the item pointed to by the \a other iterator. */ /*! \fn bool QList::iterator::operator>=(const iterator& other) const \fn bool QList::iterator::operator>=(const const_iterator& other) const Returns true if the item pointed to by this iterator is greater than or equal to the item pointed to by the \a other iterator. */ /*! \fn QList::iterator &QList::iterator::operator++() The prefix ++ operator (\c{++it}) advances the iterator to the next item in the list and returns an iterator to the new current item. Calling this function on QList::end() leads to undefined results. \sa operator--() */ /*! \fn QList::iterator QList::iterator::operator++(int) \overload The postfix ++ operator (\c{it++}) advances the iterator to the next item in the list and returns an iterator to the previously current item. */ /*! \fn QList::iterator &QList::iterator::operator--() The prefix -- operator (\c{--it}) makes the preceding item current and returns an iterator to the new current item. Calling this function on QList::begin() leads to undefined results. \sa operator++() */ /*! \fn QList::iterator QList::iterator::operator--(int) \overload The postfix -- operator (\c{it--}) makes the preceding item current and returns an iterator to the previously current item. */ /*! \fn QList::iterator &QList::iterator::operator+=(int j) Advances the iterator by \a j items. (If \a j is negative, the iterator goes backward.) \sa operator-=(), operator+() */ /*! \fn QList::iterator &QList::iterator::operator-=(int j) Makes the iterator go back by \a j items. (If \a j is negative, the iterator goes forward.) \sa operator+=(), operator-() */ /*! \fn QList::iterator QList::iterator::operator+(int j) const Returns an iterator to the item at \a j positions forward from this iterator. (If \a j is negative, the iterator goes backward.) \sa operator-(), operator+=() */ /*! \fn QList::iterator QList::iterator::operator-(int j) const Returns an iterator to the item at \a j positions backward from this iterator. (If \a j is negative, the iterator goes forward.) \sa operator+(), operator-=() */ /*! \fn int QList::iterator::operator-(iterator other) const Returns the number of items between the item pointed to by \a other and the item pointed to by this iterator. */ /*! \class QList::const_iterator \brief The QList::const_iterator class provides an STL-style const iterator for QList and QQueue. QList provides both \l{STL-style iterators} and \l{Java-style iterators}. The STL-style iterators are more low-level and more cumbersome to use; on the other hand, they are slightly faster and, for developers who already know STL, have the advantage of familiarity. QList\::const_iterator allows you to iterate over a QList\ (or a QQueue\). If you want to modify the QList as you iterate over it, use QList::iterator instead. It is generally good practice to use QList::const_iterator on a non-const QList as well, unless you need to change the QList through the iterator. Const iterators are slightly faster, and can improve code readability. The default QList::const_iterator constructor creates an uninitialized iterator. You must initialize it using a QList function like QList::constBegin(), QList::constEnd(), or QList::insert() before you can start iterating. Here's a typical loop that prints all the items stored in a list: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 19 Most QList functions accept an integer index rather than an iterator. For that reason, iterators are rarely useful in connection with QList. One place where STL-style iterators do make sense is as arguments to \l{generic algorithms}. For example, here's how to delete all the widgets stored in a QList\: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 20 Multiple iterators can be used on the same list. However, be aware that any non-const function call performed on the QList will render all existing iterators undefined. If you need to keep iterators over a long period of time, we recommend that you use QLinkedList rather than QList. \sa QList::iterator, QListIterator */ /*! \fn QList::const_iterator::const_iterator() Constructs an uninitialized iterator. Functions like operator*() and operator++() should not be called on an uninitialized iterator. Use operator=() to assign a value to it before using it. \sa QList::constBegin() QList::constEnd() */ /*! \typedef QList::const_iterator::iterator_category A synonym for \e {std::random_access_iterator_tag} indicating this iterator is a random access iterator. */ /*! \typedef QList::const_iterator::difference_type \internal */ /*! \typedef QList::const_iterator::value_type \internal */ /*! \typedef QList::const_iterator::pointer \internal */ /*! \typedef QList::const_iterator::reference \internal */ /*! \fn QList::const_iterator::const_iterator(Node *node) \internal */ /*! \fn QList::const_iterator::const_iterator(const const_iterator &other) Constructs a copy of \a other. */ /*! \fn QList::const_iterator::const_iterator(const iterator &other) Constructs a copy of \a other. */ /*! \fn const T &QList::const_iterator::operator*() const Returns the current item. \sa operator->() */ /*! \fn const T *QList::const_iterator::operator->() const Returns a pointer to the current item. \sa operator*() */ /*! \fn const T &QList::const_iterator::operator[](int j) const Returns the item at position *this + \a{j}. This function is provided to make QList iterators behave like C++ pointers. \sa operator+() */ /*! \fn bool QList::const_iterator::operator==(const const_iterator &other) const Returns true if \a other points to the same item as this iterator; otherwise returns false. \sa operator!=() */ /*! \fn bool QList::const_iterator::operator!=(const const_iterator &other) const Returns true if \a other points to a different item than this iterator; otherwise returns false. \sa operator==() */ /*! \fn bool QList::const_iterator::operator<(const const_iterator& other) const Returns true if the item pointed to by this iterator is less than the item pointed to by the \a other iterator. */ /*! \fn bool QList::const_iterator::operator<=(const const_iterator& other) const Returns true if the item pointed to by this iterator is less than or equal to the item pointed to by the \a other iterator. */ /*! \fn bool QList::const_iterator::operator>(const const_iterator& other) const Returns true if the item pointed to by this iterator is greater than the item pointed to by the \a other iterator. */ /*! \fn bool QList::const_iterator::operator>=(const const_iterator& other) const Returns true if the item pointed to by this iterator is greater than or equal to the item pointed to by the \a other iterator. */ /*! \fn QList::const_iterator &QList::const_iterator::operator++() The prefix ++ operator (\c{++it}) advances the iterator to the next item in the list and returns an iterator to the new current item. Calling this function on QList::end() leads to undefined results. \sa operator--() */ /*! \fn QList::const_iterator QList::const_iterator::operator++(int) \overload The postfix ++ operator (\c{it++}) advances the iterator to the next item in the list and returns an iterator to the previously current item. */ /*! \fn QList::const_iterator &QList::const_iterator::operator--() The prefix -- operator (\c{--it}) makes the preceding item current and returns an iterator to the new current item. Calling this function on QList::begin() leads to undefined results. \sa operator++() */ /*! \fn QList::const_iterator QList::const_iterator::operator--(int) \overload The postfix -- operator (\c{it--}) makes the preceding item current and returns an iterator to the previously current item. */ /*! \fn QList::const_iterator &QList::const_iterator::operator+=(int j) Advances the iterator by \a j items. (If \a j is negative, the iterator goes backward.) \sa operator-=(), operator+() */ /*! \fn QList::const_iterator &QList::const_iterator::operator-=(int j) Makes the iterator go back by \a j items. (If \a j is negative, the iterator goes forward.) \sa operator+=(), operator-() */ /*! \fn QList::const_iterator QList::const_iterator::operator+(int j) const Returns an iterator to the item at \a j positions forward from this iterator. (If \a j is negative, the iterator goes backward.) \sa operator-(), operator+=() */ /*! \fn QList::const_iterator QList::const_iterator::operator-(int j) const Returns an iterator to the item at \a j positions backward from this iterator. (If \a j is negative, the iterator goes forward.) \sa operator+(), operator-=() */ /*! \fn int QList::const_iterator::operator-(const_iterator other) const Returns the number of items between the item pointed to by \a other and the item pointed to by this iterator. */ /*! \fn QDataStream &operator<<(QDataStream &out, const QList &list) \relates QList Writes the list \a list 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, QList &list) \relates QList Reads a list from stream \a in into \a list. This function requires the value type to implement \c operator>>(). \sa \link datastreamformat.html Format of the QDataStream operators \endlink */ /*! \fn iterator QList::remove(iterator pos) Use erase() instead. */ /*! \fn int QList::remove(const T &t) Use removeAll() instead. */ /*! \fn int QList::findIndex(const T& t) const Use indexOf() instead. */ /*! \fn iterator QList::find(const T& t) Use indexOf() instead. */ /*! \fn const_iterator QList::find (const T& t) const Use indexOf() instead. */ /*! \fn iterator QList::find(iterator from, const T& t) Use indexOf() instead. */ /*! \fn const_iterator QList::find(const_iterator from, const T& t) const Use indexOf() instead. */ /*! \fn QList QList::fromVector(const QVector &vector) Returns a QList object with the data contained in \a vector. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 21 \sa fromSet(), toVector(), QVector::toList() */ /*! \fn QVector QList::toVector() const Returns a QVector object with the data contained in this QList. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 22 \sa toSet(), fromVector(), QVector::fromList() */ /*! \fn QList QList::fromSet(const QSet &set) Returns a QList object with the data contained in \a set. The order of the elements in the QList is undefined. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 23 \sa fromVector(), toSet(), QSet::toList(), qSort() */ /*! \fn QSet QList::toSet() const Returns a QSet object with the data contained in this QList. Since QSet doesn't allow duplicates, the resulting QSet might be smaller than the original list was. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 24 \sa toVector(), fromSet(), QSet::fromList() */ /*! \fn QList QList::fromStdList(const std::list &list) Returns a QList object with the data contained in \a list. The order of the elements in the QList is the same as in \a list. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 25 \sa toStdList(), QVector::fromStdVector() */ /*! \fn std::list QList::toStdList() const Returns a std::list object with the data contained in this QList. Example: \snippet doc/src/snippets/code/src_corelib_tools_qlistdata.cpp 26 \sa fromStdList(), QVector::toStdVector() */ QT_END_NAMESPACE