685 lines
22 KiB
C++
685 lines
22 KiB
C++
// Iterators -*- C++ -*-
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// Copyright (C) 2001, 2002 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 2, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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/*
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*
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* Copyright (c) 1994
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* Hewlett-Packard Company
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Hewlett-Packard Company makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*
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*
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* Copyright (c) 1996-1998
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* Silicon Graphics Computer Systems, Inc.
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Silicon Graphics makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*/
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/** @file stl_iterator.h
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* This is an internal header file, included by other library headers.
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* You should not attempt to use it directly.
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*
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* This file implements reverse_iterator, back_insert_iterator,
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* front_insert_iterator, insert_iterator, __normal_iterator, and their
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* supporting functions and overloaded operators.
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*/
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#ifndef __GLIBCPP_INTERNAL_ITERATOR_H
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#define __GLIBCPP_INTERNAL_ITERATOR_H
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namespace std
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{
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// 24.4.1 Reverse iterators
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/**
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* "Bidirectional and random access iterators have corresponding reverse
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* %iterator adaptors that iterate through the data structure in the
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* opposite direction. They have the same signatures as the corresponding
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* iterators. The fundamental relation between a reverse %iterator and its
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* corresponding %iterator @c i is established by the identity:
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* @code
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* &*(reverse_iterator(i)) == &*(i - 1)
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* @endcode
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*
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* This mapping is dictated by the fact that while there is always a
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* pointer past the end of an array, there might not be a valid pointer
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* before the beginning of an array." [24.4.1]/1,2
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*
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* Reverse iterators can be tricky and surprising at first. Their
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* semantics make sense, however, and the trickiness is a side effect of
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* the requirement that the iterators must be safe.
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*/
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template<typename _Iterator>
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class reverse_iterator
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: public iterator<typename iterator_traits<_Iterator>::iterator_category,
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typename iterator_traits<_Iterator>::value_type,
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typename iterator_traits<_Iterator>::difference_type,
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typename iterator_traits<_Iterator>::pointer,
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typename iterator_traits<_Iterator>::reference>
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{
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protected:
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_Iterator current;
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public:
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typedef _Iterator iterator_type;
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typedef typename iterator_traits<_Iterator>::difference_type
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difference_type;
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typedef typename iterator_traits<_Iterator>::reference reference;
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typedef typename iterator_traits<_Iterator>::pointer pointer;
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public:
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/**
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* The default constructor gives an undefined state to this %iterator.
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*/
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reverse_iterator() { }
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/**
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* This %iterator will move in the opposite direction that @p x does.
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*/
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explicit
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reverse_iterator(iterator_type __x) : current(__x) { }
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/**
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* The copy constructor is normal.
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*/
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reverse_iterator(const reverse_iterator& __x)
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: current(__x.current) { }
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/**
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* A reverse_iterator across other types can be copied in the normal
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* fashion.
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*/
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template<typename _Iter>
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reverse_iterator(const reverse_iterator<_Iter>& __x)
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: current(__x.base()) { }
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/**
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* @return @c current, the %iterator used for underlying work.
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*/
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iterator_type
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base() const { return current; }
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/**
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* @return TODO
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*
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* @doctodo
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*/
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reference
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operator*() const
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{
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_Iterator __tmp = current;
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return *--__tmp;
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}
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/**
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* @return TODO
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*
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* @doctodo
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*/
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pointer
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operator->() const { return &(operator*()); }
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/**
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* @return TODO
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*
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* @doctodo
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*/
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reverse_iterator&
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operator++()
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{
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--current;
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return *this;
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}
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/**
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* @return TODO
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*
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* @doctodo
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*/
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reverse_iterator
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operator++(int)
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{
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reverse_iterator __tmp = *this;
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--current;
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return __tmp;
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}
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/**
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* @return TODO
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*
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* @doctodo
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*/
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reverse_iterator&
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operator--()
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{
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++current;
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return *this;
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}
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/**
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* @return TODO
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*
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* @doctodo
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*/
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reverse_iterator operator--(int)
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{
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reverse_iterator __tmp = *this;
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++current;
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return __tmp;
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}
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/**
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* @return TODO
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*
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* @doctodo
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*/
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reverse_iterator
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operator+(difference_type __n) const
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{ return reverse_iterator(current - __n); }
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/**
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* @return TODO
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*
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* @doctodo
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*/
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reverse_iterator&
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operator+=(difference_type __n)
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{
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current -= __n;
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return *this;
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}
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/**
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* @return TODO
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*
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* @doctodo
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*/
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reverse_iterator
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operator-(difference_type __n) const
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{ return reverse_iterator(current + __n); }
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/**
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* @return TODO
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*
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* @doctodo
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*/
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reverse_iterator&
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operator-=(difference_type __n)
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{
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current += __n;
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return *this;
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}
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/**
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* @return TODO
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*
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* @doctodo
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*/
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reference
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operator[](difference_type __n) const { return *(*this + __n); }
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};
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//@{
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/**
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* @param x A %reverse_iterator.
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* @param y A %reverse_iterator.
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* @return A simple bool.
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*
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* Reverse iterators forward many operations to their underlying base()
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* iterators. Others are implemented in terms of one another.
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*
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*/
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template<typename _Iterator>
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inline bool
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operator==(const reverse_iterator<_Iterator>& __x,
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const reverse_iterator<_Iterator>& __y)
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{ return __x.base() == __y.base(); }
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template<typename _Iterator>
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inline bool
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operator<(const reverse_iterator<_Iterator>& __x,
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const reverse_iterator<_Iterator>& __y)
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{ return __y.base() < __x.base(); }
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template<typename _Iterator>
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inline bool
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operator!=(const reverse_iterator<_Iterator>& __x,
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const reverse_iterator<_Iterator>& __y)
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{ return !(__x == __y); }
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template<typename _Iterator>
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inline bool
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operator>(const reverse_iterator<_Iterator>& __x,
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const reverse_iterator<_Iterator>& __y)
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{ return __y < __x; }
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template<typename _Iterator>
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inline bool
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operator<=(const reverse_iterator<_Iterator>& __x,
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const reverse_iterator<_Iterator>& __y)
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{ return !(__y < __x); }
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template<typename _Iterator>
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inline bool
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operator>=(const reverse_iterator<_Iterator>& __x,
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const reverse_iterator<_Iterator>& __y)
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{ return !(__x < __y); }
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template<typename _Iterator>
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inline typename reverse_iterator<_Iterator>::difference_type
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operator-(const reverse_iterator<_Iterator>& __x,
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const reverse_iterator<_Iterator>& __y)
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{ return __y.base() - __x.base(); }
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template<typename _Iterator>
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inline reverse_iterator<_Iterator>
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operator+(typename reverse_iterator<_Iterator>::difference_type __n,
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const reverse_iterator<_Iterator>& __x)
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{ return reverse_iterator<_Iterator>(__x.base() - __n); }
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//@}
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// 24.4.2.2.1 back_insert_iterator
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/**
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* These are output iterators, constructed from a container-of-T.
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* Assigning a T to the iterator appends it to the container using
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* push_back.
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*
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* Tip: Using the back_inserter function to create these iterators can
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* save typing.
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*/
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template<typename _Container>
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class back_insert_iterator
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: public iterator<output_iterator_tag, void, void, void, void>
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{
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protected:
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_Container* container;
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public:
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/// A nested typedef for the type of whatever container you used.
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typedef _Container container_type;
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/// The only way to create this %iterator is with a container.
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explicit
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back_insert_iterator(_Container& __x) : container(&__x) { }
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/**
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* @param value An instance of whatever type
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* container_type::const_reference is; presumably a
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* reference-to-const T for container<T>.
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* @return This %iterator, for chained operations.
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*
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* This kind of %iterator doesn't really have a "position" in the
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* container (you can think of the position as being permanently at
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* the end, if you like). Assigning a value to the %iterator will
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* always append the value to the end of the container.
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*/
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back_insert_iterator&
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operator=(typename _Container::const_reference __value)
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{
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container->push_back(__value);
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return *this;
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}
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/// Simply returns *this.
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back_insert_iterator&
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operator*() { return *this; }
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/// Simply returns *this. (This %iterator does not "move".)
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back_insert_iterator&
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operator++() { return *this; }
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/// Simply returns *this. (This %iterator does not "move".)
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back_insert_iterator
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operator++(int) { return *this; }
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};
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/**
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* @param x A container of arbitrary type.
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* @return An instance of back_insert_iterator working on @p x.
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*
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* This wrapper function helps in creating back_insert_iterator instances.
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* Typing the name of the %iterator requires knowing the precise full
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* type of the container, which can be tedious and impedes generic
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* programming. Using this function lets you take advantage of automatic
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* template parameter deduction, making the compiler match the correct
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* types for you.
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*/
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template<typename _Container>
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inline back_insert_iterator<_Container>
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back_inserter(_Container& __x)
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{ return back_insert_iterator<_Container>(__x); }
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/**
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* These are output iterators, constructed from a container-of-T.
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* Assigning a T to the iterator prepends it to the container using
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* push_front.
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*
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* Tip: Using the front_inserter function to create these iterators can
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* save typing.
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*/
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template<typename _Container>
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class front_insert_iterator
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: public iterator<output_iterator_tag, void, void, void, void>
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{
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protected:
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_Container* container;
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public:
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/// A nested typedef for the type of whatever container you used.
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typedef _Container container_type;
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/// The only way to create this %iterator is with a container.
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explicit front_insert_iterator(_Container& __x) : container(&__x) { }
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/**
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* @param value An instance of whatever type
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* container_type::const_reference is; presumably a
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* reference-to-const T for container<T>.
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* @return This %iterator, for chained operations.
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*
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* This kind of %iterator doesn't really have a "position" in the
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* container (you can think of the position as being permanently at
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* the front, if you like). Assigning a value to the %iterator will
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* always prepend the value to the front of the container.
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*/
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front_insert_iterator&
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operator=(typename _Container::const_reference __value)
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{
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container->push_front(__value);
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return *this;
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}
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/// Simply returns *this.
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front_insert_iterator&
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operator*() { return *this; }
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/// Simply returns *this. (This %iterator does not "move".)
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front_insert_iterator&
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operator++() { return *this; }
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/// Simply returns *this. (This %iterator does not "move".)
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front_insert_iterator
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operator++(int) { return *this; }
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};
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/**
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* @param x A container of arbitrary type.
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* @return An instance of front_insert_iterator working on @p x.
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*
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* This wrapper function helps in creating front_insert_iterator instances.
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* Typing the name of the %iterator requires knowing the precise full
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* type of the container, which can be tedious and impedes generic
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* programming. Using this function lets you take advantage of automatic
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* template parameter deduction, making the compiler match the correct
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* types for you.
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*/
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template<typename _Container>
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inline front_insert_iterator<_Container>
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front_inserter(_Container& __x)
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{ return front_insert_iterator<_Container>(__x); }
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/**
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* These are output iterators, constructed from a container-of-T.
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* Assigning a T to the iterator inserts it in the container at the
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* %iterator's position, rather than overwriting the value at that
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* position.
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*
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* (Sequences will actually insert a @e copy of the value before the
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* %iterator's position.)
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*
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* Tip: Using the inserter function to create these iterators can
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* save typing.
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*/
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template<typename _Container>
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class insert_iterator
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: public iterator<output_iterator_tag, void, void, void, void>
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{
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protected:
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_Container* container;
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typename _Container::iterator iter;
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public:
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/// A nested typedef for the type of whatever container you used.
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typedef _Container container_type;
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/**
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* The only way to create this %iterator is with a container and an
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* initial position (a normal %iterator into the container).
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*/
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insert_iterator(_Container& __x, typename _Container::iterator __i)
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: container(&__x), iter(__i) {}
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/**
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* @param value An instance of whatever type
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* container_type::const_reference is; presumably a
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* reference-to-const T for container<T>.
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* @return This %iterator, for chained operations.
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*
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* This kind of %iterator maintains its own position in the
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* container. Assigning a value to the %iterator will insert the
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* value into the container at the place before the %iterator.
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*
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* The position is maintained such that subsequent assignments will
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* insert values immediately after one another. For example,
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* @code
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* // vector v contains A and Z
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*
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* insert_iterator i (v, ++v.begin());
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* i = 1;
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* i = 2;
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* i = 3;
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*
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* // vector v contains A, 1, 2, 3, and Z
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* @endcode
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*/
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insert_iterator&
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operator=(const typename _Container::const_reference __value)
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{
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iter = container->insert(iter, __value);
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++iter;
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return *this;
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}
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/// Simply returns *this.
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insert_iterator&
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operator*() { return *this; }
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/// Simply returns *this. (This %iterator does not "move".)
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insert_iterator&
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operator++() { return *this; }
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/// Simply returns *this. (This %iterator does not "move".)
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insert_iterator&
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operator++(int) { return *this; }
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};
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/**
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* @param x A container of arbitrary type.
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* @return An instance of insert_iterator working on @p x.
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*
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* This wrapper function helps in creating insert_iterator instances.
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* Typing the name of the %iterator requires knowing the precise full
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* type of the container, which can be tedious and impedes generic
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* programming. Using this function lets you take advantage of automatic
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* template parameter deduction, making the compiler match the correct
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* types for you.
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*/
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template<typename _Container, typename _Iterator>
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inline insert_iterator<_Container>
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inserter(_Container& __x, _Iterator __i)
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{
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return insert_iterator<_Container>(__x,
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typename _Container::iterator(__i));
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}
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// This iterator adapter is 'normal' in the sense that it does not
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// change the semantics of any of the operators of its iterator
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// parameter. Its primary purpose is to convert an iterator that is
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// not a class, e.g. a pointer, into an iterator that is a class.
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// The _Container parameter exists solely so that different containers
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// using this template can instantiate different types, even if the
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// _Iterator parameter is the same.
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template<typename _Iterator, typename _Container>
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class __normal_iterator
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: public iterator<typename iterator_traits<_Iterator>::iterator_category,
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typename iterator_traits<_Iterator>::value_type,
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typename iterator_traits<_Iterator>::difference_type,
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typename iterator_traits<_Iterator>::pointer,
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typename iterator_traits<_Iterator>::reference>
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{
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protected:
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_Iterator _M_current;
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public:
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typedef typename iterator_traits<_Iterator>::difference_type
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difference_type;
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typedef typename iterator_traits<_Iterator>::reference reference;
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typedef typename iterator_traits<_Iterator>::pointer pointer;
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__normal_iterator() : _M_current(_Iterator()) { }
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explicit
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__normal_iterator(const _Iterator& __i) : _M_current(__i) { }
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// Allow iterator to const_iterator conversion
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template<typename _Iter>
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inline __normal_iterator(const __normal_iterator<_Iter, _Container>& __i)
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: _M_current(__i.base()) { }
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// Forward iterator requirements
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reference
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operator*() const { return *_M_current; }
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pointer
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operator->() const { return _M_current; }
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__normal_iterator&
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operator++() { ++_M_current; return *this; }
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__normal_iterator
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operator++(int) { return __normal_iterator(_M_current++); }
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// Bidirectional iterator requirements
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__normal_iterator&
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operator--() { --_M_current; return *this; }
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__normal_iterator
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operator--(int) { return __normal_iterator(_M_current--); }
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// Random access iterator requirements
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reference
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operator[](const difference_type& __n) const
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{ return _M_current[__n]; }
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__normal_iterator&
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operator+=(const difference_type& __n)
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{ _M_current += __n; return *this; }
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__normal_iterator
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operator+(const difference_type& __n) const
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{ return __normal_iterator(_M_current + __n); }
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__normal_iterator&
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operator-=(const difference_type& __n)
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{ _M_current -= __n; return *this; }
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__normal_iterator
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operator-(const difference_type& __n) const
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{ return __normal_iterator(_M_current - __n); }
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difference_type
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operator-(const __normal_iterator& __i) const
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{ return _M_current - __i._M_current; }
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const _Iterator&
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base() const { return _M_current; }
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};
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// Forward iterator requirements
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template<typename _IteratorL, typename _IteratorR, typename _Container>
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inline bool
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operator==(const __normal_iterator<_IteratorL, _Container>& __lhs,
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const __normal_iterator<_IteratorR, _Container>& __rhs)
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{ return __lhs.base() == __rhs.base(); }
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template<typename _IteratorL, typename _IteratorR, typename _Container>
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inline bool
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operator!=(const __normal_iterator<_IteratorL, _Container>& __lhs,
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const __normal_iterator<_IteratorR, _Container>& __rhs)
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{ return !(__lhs == __rhs); }
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// Random access iterator requirements
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template<typename _IteratorL, typename _IteratorR, typename _Container>
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inline bool
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operator<(const __normal_iterator<_IteratorL, _Container>& __lhs,
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const __normal_iterator<_IteratorR, _Container>& __rhs)
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{ return __lhs.base() < __rhs.base(); }
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template<typename _IteratorL, typename _IteratorR, typename _Container>
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inline bool
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operator>(const __normal_iterator<_IteratorL, _Container>& __lhs,
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const __normal_iterator<_IteratorR, _Container>& __rhs)
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{ return __rhs < __lhs; }
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template<typename _IteratorL, typename _IteratorR, typename _Container>
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inline bool
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operator<=(const __normal_iterator<_IteratorL, _Container>& __lhs,
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const __normal_iterator<_IteratorR, _Container>& __rhs)
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{ return !(__rhs < __lhs); }
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template<typename _IteratorL, typename _IteratorR, typename _Container>
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inline bool
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operator>=(const __normal_iterator<_IteratorL, _Container>& __lhs,
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const __normal_iterator<_IteratorR, _Container>& __rhs)
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{ return !(__lhs < __rhs); }
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template<typename _Iterator, typename _Container>
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inline __normal_iterator<_Iterator, _Container>
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operator+(typename __normal_iterator<_Iterator, _Container>::difference_type __n,
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const __normal_iterator<_Iterator, _Container>& __i)
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{ return __normal_iterator<_Iterator, _Container>(__i.base() + __n); }
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} // namespace std
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#endif
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// Local Variables:
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// mode:C++
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// End:
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