path: root/doc/qptrvector.doc

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/*****************************************************************************
  QPtrVector documentation
 *****************************************************************************/

/*!
    \class QPtrVector qptrvector.h
    \brief The QPtrVector class is a template collection class that
    provides a vector (array).

    \ingroup tools

    \important autoDelete setAutoDelete

    QValueVector is an STL-compatible alternative to this class.

    QPtrVector is implemented as a template class. Defines a template
    instance QPtrVector\<X\> to create a vector that contains pointers
    to X (X*).

    A vector is the same as an array. The main difference between
    QPtrVector and QMemArray is that QPtrVector stores pointers to the
    elements, whereas QMemArray stores the elements themselves (i.e.
    QMemArray is value-based and QPtrVector is pointer-based).

    Items are added to the vector using insert() or fill(). Items are
    removed with remove(). You can get a pointer to an item at a
    particular index position using at().

    Unless otherwise stated, all functions that remove items from the
    vector will also delete the element pointed to if \link
    setAutoDelete() auto-deletion\endlink is enabled. By default,
    auto-deletion is disabled; see setAutoDelete(). This behaviour can
    be changed in a subclass by reimplementing the virtual function
    deleteItem().

    Functions that compare items (find() and sort() for example) will
    do so using the virtual function compareItems(). The default
    implementation of this function only compares the pointer values.
    Reimplement compareItems() in a subclass to get searching and
    sorting based on the item contents. You can perform a linear
    search for a pointer in the vector using findRef(), or a binary
    search (of a sorted vector) using bsearch(). You can count the
    number of times an item appears in the vector with contains() or
    containsRef().

    \sa QMemArray
*/

/*!
    \fn QPtrVector::QPtrVector()

    Constructs a null vector.

    \sa isNull()
*/

/*!
    \fn QPtrVector::QPtrVector( uint size )

    Constructs an vector with room for \a size items. Makes a null
    vector if \a size == 0.

    All \a size positions in the vector are initialized to 0.

    \sa size(), resize(), isNull()
*/

/*!
    \fn QPtrVector::QPtrVector( const QPtrVector<type> &v )

    Constructs a copy of \a v. Only the pointers are copied (i.e.
    shallow copy).
*/

/*!
    \fn QPtrVector::~QPtrVector()

    Removes all items from the vector, and destroys the vector itself.

    \sa clear()
*/

/*!
    \fn QPtrVector<type> &QPtrVector::operator=( const QPtrVector<type> &v )

    Assigns \a v to this vector and returns a reference to this
    vector.

    This vector is first cleared and then all the items from \a v are
    copied into the vector. Only the pointers are copied (i.e. shallow
    copy).

    \sa clear()
*/

/*!
    \fn type **QPtrVector::data() const

    Returns a pointer to the actual vector data, which is an array of
    type*.

    The vector is a null vector if data() == 0 (null pointer).

    \sa isNull()
*/

/*!
    \fn uint QPtrVector::size() const

    Returns the size of the vector, i.e. the number of vector
    positions. This is also the maximum number of items the vector can
    hold.

    The vector is a null vector if size() == 0.

    \sa isNull(), resize(), count()
*/

/*!
    \fn uint QPtrVector::count() const 

    Returns the number of items in the vector. The vector is empty if
    count() == 0.

    \sa isEmpty(), size(), isNull()
*/

/*!
    \fn bool QPtrVector::isEmpty() const

    Returns TRUE if the vector is empty; otherwise returns FALSE.

    \sa count()
*/

/*!
    \fn bool QPtrVector::isNull() const

    Returns TRUE if the vector is null; otherwise returns FALSE.

    A null vector has size() == 0 and data() == 0.

    \sa size()
*/

/*!
    \fn bool QPtrVector::resize( uint size )

    Resizes (expands or shrinks) the vector to \a size elements. The
    vector becomes a null vector if \a size == 0.

    Any items at position \a size or beyond in the vector are removed.
    New positions are initialized to 0.

    Returns TRUE if successful, i.e. if the memory was successfully
    allocated; otherwise returns FALSE.

    \sa size(), isNull()
*/

/*!
    \fn bool QPtrVector::insert( uint i, const type *d )

    Sets position \a i in the vector to contain the item \a d. \a i
    must be less than size(). Any previous element in position \a i is
    removed.

    \sa at()
*/

/*!
    \fn bool QPtrVector::remove( uint i )

    Removes the item at position \a i in the vector, if there is one.
    \a i must be less than size().

    Returns TRUE if \a i is within range; otherwise returns FALSE.

    \sa take(), at()
*/

/*!
    \fn type* QPtrVector::take( uint i )

    Returns the item at position \a i in the vector, and removes that
    item from the vector. \a i must be less than size(). If there is
    no item at position \a i, 0 is returned.

    Unlike remove(), this function does \e not call deleteItem() for
    the removed item.

    \sa remove(), at()
*/

/*!
    \fn void QPtrVector::clear()

    Removes all items from the vector, and destroys the vector itself.

    The vector becomes a null vector.

    \sa isNull()
*/

/*!
    \fn bool QPtrVector::fill( const type *d, int size )

    Inserts item \a d in all positions in the vector. Any existing
    items are removed. If \a d is 0, the vector becomes empty.

    If \a size >= 0, the vector is first resized to \a size. By
    default, \a size is -1.

    Returns TRUE if successful, i.e. \a size is the same as the
    current size, or \a size is larger and the memory has successfully
    been allocated; otherwise returns FALSE.

    \sa resize(), insert(), isEmpty()
*/

/*!
    \fn void QPtrVector::sort()

    Sorts the items in ascending order. Any empty positions will be
    put last.

    Compares items using the virtual function compareItems().

    \sa bsearch()
*/

/*!
    \fn int QPtrVector::bsearch( const type* d ) const

    In a sorted array, finds the first occurrence of \a d using a
    binary search. For a sorted array, this is generally much faster
    than find(), which performs a linear search.

    Returns the position of \a d, or -1 if \a d could not be found. \a
    d must not be 0.

    Compares items using the virtual function compareItems().

    \sa sort(), find()
*/


/*!
    \fn int QPtrVector::findRef( const type *d, uint i ) const

    Finds the first occurrence of the item pointer \a d in the vector
    using a linear search. The search starts at position \a i, which
    must be less than size(). \a i is by default 0; i.e. the search
    starts at the start of the vector.

    Returns the position of \a d, or -1 if \a d could not be found.

    This function does \e not use compareItems() to compare items.

    Use the much faster bsearch() to search a sorted vector.

    \sa find(), bsearch()
*/

/*!
    \fn int QPtrVector::find( const type *d, uint i ) const

    Finds the first occurrence of item \a d in the vector using a
    linear search. The search starts at position \a i, which must be
    less than size(). \a i is by default 0; i.e. the search starts at
    the start of the vector.

    Returns the position of \a d, or -1 if \a d could not be found.

    Compares items using the virtual function compareItems().

    Use the much faster bsearch() to search a sorted vector.

    \sa findRef(), bsearch()
*/


/*!
    \fn uint QPtrVector::containsRef( const type *d ) const

    Returns the number of occurrences of the item pointer \a d in the
    vector.

    This function does \e not use compareItems() to compare items.

    \sa findRef()
*/

/*!
    \fn uint QPtrVector::contains( const type *d ) const

    Returns the number of occurrences of item \a d in the vector.

    Compares items using the virtual function compareItems().

    \sa containsRef()
*/

/*!
    \fn type *QPtrVector::operator[]( int i ) const

    Returns the item at position \a i, or 0 if there is no item at
    that position. \a i must be less than size().

    Equivalent to at( \a i ).

    \sa at()
*/

/*!
    \fn type *QPtrVector::at( uint i ) const

    Returns the item at position \a i, or 0 if there is no item at
    that position. \a i must be less than size().
*/


/*!
    \fn void QPtrVector::toList( QGList *list ) const

    \internal

    Copies all items in this vector to the list \a list. \a list is
    first cleared and then all items are appended to \a list.

    \sa QPtrList, QPtrStack, QPtrQueue
*/

/*!
    \fn int QPtrVector::compareItems( QPtrCollection::Item d1,
					QPtrCollection::Item d2 )

    This virtual function compares two list items.

    Returns:
    \list
    \i zero if \a d1 == \a d2
    \i nonzero if \a d1 != \a d2
    \endlist

    This function returns \e int rather than \e bool so that
    reimplementations can return one of three values and use it to
    sort by:
    \list
    \i 0 if \a d1 == \a d2
    \i \> 0 (positive integer) if \a d1 \> \a d2
    \i \< 0 (negative integer) if \a d1 \< \a d2
    \endlist

    The sort() and bsearch() functions retquire compareItems() to be
    implemented as described here.

    This function should not modify the vector because some const
    functions call compareItems().
*/

/*!
    \fn QDataStream& QPtrVector::read( QDataStream &s,
					QPtrCollection::Item &item )

    Reads a vector item, \a item, from the stream \a s and returns a
    reference to the stream.

    The default implementation sets \a item to 0.

    \sa write()
*/

/*!
    \fn QDataStream& QPtrVector::write( QDataStream &s,
					QPtrCollection::Item item ) const

    Writes a vector item, \a item, to the stream \a s and returns a
    reference to the stream.

    The default implementation does nothing.

    \sa read()
*/
    
/*!
    \fn bool QPtrVector::operator==( const QPtrVector<type> &v ) const

    Returns TRUE if this vector and \a v are equal; otherwise returns
    FALSE.
*/