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#ifndef QPID_ISLIST_H
#define QPID_ISLIST_H
/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
#include <boost/iterator/iterator_adaptor.hpp>
#include <boost/noncopyable.hpp>
#include "pointer_to_other.h"
namespace qpid {
template <class Pointer> struct Pointee {
typedef typename Pointer::element_type type;
};
template <class T> struct Pointee<T*> {
typedef T type;
};
template <class> class ISList;
template <class> class IList;
/** Base class for values (nodes) in an ISList.
*@param raw or smart-pointer type to use for the "next" pointer.
* Using a smart pointer like shared_ptr or intrusive_ptr
* will automate memory management.
*/
template <class Pointer> class ISListNode {
public:
typedef Pointer pointer;
typedef typename Pointee<Pointer>::type NodeType;
typedef typename pointer_to_other<Pointer, const NodeType>::type const_pointer;
protected:
ISListNode() : next() {}
ISListNode(const ISListNode&) {} // Don't copy the next pointer.
pointer getNext() { return next; }
const_pointer getNext() const { return next; }
private:
pointer next;
friend class ISList<NodeType>;
};
/**
* Intrusive singly-linked list.
*
* Provides forward iterator, constant time insertion and constant
* time pop_front (but not pop_back) so makes a good queue
* implementation.
*
* Unlike standard containers insert(), push_front() and push_back()
* take const pointer& rather than const value_type&.
*
* Iterators can be converted to pointers.
*
* Noncopyable - intrusively linked nodes cannot be shared.
*
* @param Node value type for the list, must derive from ISListNode<T>.
*/
template <class Node> class ISList : private boost::noncopyable {
template <class> class Iterator;
public:
typedef Node value_type;
typedef typename Node::pointer pointer;
typedef typename Node::const_pointer const_pointer;
typedef value_type& reference;
typedef const value_type& const_reference;
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef Iterator<value_type> iterator;
typedef Iterator<const value_type> const_iterator;
ISList() : first(pointer()), end_(&first) {}
iterator begin() { return iterator(&first); }
const_iterator begin() const { return const_iterator(&first); }
iterator end() { return end_; }
const_iterator end() const { return end_; }
bool empty() const { return begin() == end(); }
size_type size() const {
int s = 0;
for (const_iterator i=begin(); i != end(); ++i)
++s;
return s;
}
void swap(ISList &x) { swap(first, x.first); swap(end_, x.end_); }
/** Unlike standard containers, insert takes a const pointer&, not a
* const value_type&. The value is not copied, only linked into the list.
*/
iterator insert(iterator i, const pointer& p) {
p->next = *(i.pptr);
*(i.pptr) = p;
if (i==end_) ++end_;
return i;
}
void erase(iterator i) {
if (&i->next == end_.pptr)
end_ = i;
*(i.pptr) = (**(i.pptr)).next;
}
void erase(iterator i, iterator j) { while(i != j) erase(i); }
void clear() { while (!empty()) { erase(begin()); } }
reference front() { return *begin(); }
const_reference front() const { return *begin(); }
void pop_front() { erase(begin()); }
void push_front(pointer x) { insert(begin(), x); }
void push_back(pointer x) { insert(end(), x); }
private:
template <class T>
class Iterator : public boost::iterator_facade <
Iterator<T>, T, boost::forward_traversal_tag>
{
public:
Iterator() {};
template <class U> Iterator(
const Iterator<U>& i,
typename boost::enable_if_convertible<U*, T*>::type* = 0
) : pptr(i.pptr) {}
operator pointer() { return *pptr; }
operator const_pointer() const { return *pptr; }
private:
friend class boost::iterator_core_access;
Iterator(const pointer* pp) : pptr(const_cast<pointer*>(pp)) {};
T& dereference() const { return **pptr; }
void increment() { pptr = &(**pptr).next; }
bool equal(const Iterator& x) const { return pptr == x.pptr; }
pointer* pptr;
friend class ISList<Node>;
};
private:
pointer first;
iterator end_;
};
} // namespace qpid
#endif /*!QPID_ISLIST_H*/
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