scummvm/common/list.h
Max Horn 5181546c63 Rewrote Common::List iterator code to ensure const correctness is preserved.
We tried to implement the list iterators in a clever way, to reduce code
duplication. But this is essentially impossible to do properly, sadly --
this is one of the places where the ugly drawbacks of C++ really show.
As a consequence, our implementation had a bug which allowed one to
convert any const_iterator to an iterator, thus allowing modifying
elements of const lists.

This rewrite reintroduces code duplication but at least ensures that no
const list is written to accidentally.

Also fix some places which incorrectly used iterator instead of const_iterator
or (in the kyra code) accidentally wrote into a const list.

svn-id: r39279
2009-03-09 22:26:02 +00:00

197 lines
4.1 KiB
C++

/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*/
#ifndef COMMON_LIST_H
#define COMMON_LIST_H
#include "common/list_intern.h"
namespace Common {
/**
* Simple double linked list, modeled after the list template of the standard
* C++ library.
*/
template<typename t_T>
class List {
protected:
typedef ListInternal::NodeBase NodeBase;
typedef ListInternal::Node<t_T> Node;
NodeBase _anchor;
public:
typedef ListInternal::Iterator<t_T> iterator;
typedef ListInternal::ConstIterator<t_T> const_iterator;
typedef t_T value_type;
public:
List() {
_anchor._prev = &_anchor;
_anchor._next = &_anchor;
}
List(const List<t_T> &list) {
_anchor._prev = &_anchor;
_anchor._next = &_anchor;
insert(begin(), list.begin(), list.end());
}
~List() {
clear();
}
void push_front(const t_T &element) {
insert(begin(), element);
}
void push_back(const t_T &element) {
insert(end(), element);
}
void insert(iterator pos, const t_T &element) {
ListInternal::NodeBase *newNode = new Node(element);
newNode->_next = pos._node;
newNode->_prev = pos._node->_prev;
newNode->_prev->_next = newNode;
newNode->_next->_prev = newNode;
}
template<typename iterator2>
void insert(iterator pos, iterator2 first, iterator2 last) {
for (; first != last; ++first)
insert(pos, *first);
}
iterator erase(iterator pos) {
assert(pos != end());
NodeBase *next = pos._node->_next;
NodeBase *prev = pos._node->_prev;
Node *node = static_cast<Node *>(pos._node);
prev->_next = next;
next->_prev = prev;
delete node;
return iterator(next);
}
iterator reverse_erase(iterator pos) {
assert(pos != end());
NodeBase *next = pos._node->_next;
NodeBase *prev = pos._node->_prev;
Node *node = static_cast<Node *>(pos._node);
prev->_next = next;
next->_prev = prev;
delete node;
return iterator(prev);
}
iterator erase(iterator first, iterator last) {
while (first != last)
erase(first++);
return last;
}
void remove(const t_T &val) {
iterator i = begin();
while (i != end())
if (val == i.operator*())
i = erase(i);
else
++i;
}
void pop_front() {
iterator i = begin();
i = erase(i);
}
List<t_T> &operator=(const List<t_T> &list) {
if (this != &list) {
iterator i;
const_iterator j;
for (i = begin(), j = list.begin(); (i != end()) && (j != list.end()) ; ++i, ++j) {
static_cast<Node *>(i._node)->_data = static_cast<const Node *>(j._node)->_data;
}
if (i == end())
insert(i, j, list.end());
else
erase(i, end());
}
return *this;
}
uint size() const {
int n = 0;
for (const_iterator i = begin(); i != end(); ++i)
++n;
return n;
}
void clear() {
erase(begin(), end());
}
bool empty() const {
return (&_anchor == _anchor._next);
}
iterator begin() {
return iterator(_anchor._next);
}
iterator reverse_begin() {
return iterator(_anchor._prev);
}
iterator end() {
return iterator(&_anchor);
}
const_iterator begin() const {
return const_iterator(_anchor._next);
}
const_iterator reverse_begin() const {
return const_iterator(_anchor._prev);
}
const_iterator end() const {
return const_iterator(const_cast<NodeBase*>(&_anchor));
}
};
} // End of namespace Common
#endif