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/*
Copyright (C) 2020 Red Hat, Inc.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
/* Implementation of a list with more "safe" iterators.
* Specifically the item under an iterator can be removed while scanning
* the list. This to allow objects in the list to delete themselves from
* the list.
*/
#pragma once
#include <memory>
#include <forward_list>
#include <algorithm>
#include <glib.h>
#include "push-visibility.h"
namespace red {
template <class T>
struct Mallocator
{
typedef T value_type;
Mallocator() = default;
template <class U>
constexpr Mallocator(const Mallocator<U>&) noexcept
{
}
T* allocate(size_t n)
{
return static_cast<T*>(g_malloc_n(n, sizeof(T)));
}
void deallocate(T* p, size_t) noexcept
{
g_free(p);
}
};
template <class T, class U>
bool operator==(const Mallocator<T>&, const Mallocator<U>&)
{
return true;
}
template <class T, class U>
bool operator!=(const Mallocator<T>&, const Mallocator<U>&)
{
return false;
}
template <typename T>
class safe_list
{
typedef typename std::forward_list<T> wrapped;
typename std::forward_list<T,Mallocator<T>> list;
class iterator;
public:
void push_front(const T& v)
{
list.push_front(v);
}
void remove(const T& v)
{
list.remove(v);
}
void clear()
{
list.clear();
}
void pop_front()
{
list.pop_front();
}
iterator begin() noexcept
{
return iterator(list.begin());
}
iterator end() noexcept
{
return iterator(list.end());
}
size_t size()
{
return std::distance(begin(), end());
}
bool empty() const
{
return list.empty();
}
};
template <typename T>
class safe_list<T>::iterator
{
typedef typename std::forward_list<T,Mallocator<T>>::iterator wrapped;
wrapped curr, next;
public:
using iterator_category = std::forward_iterator_tag;
using value_type = T;
using difference_type = ptrdiff_t;
using pointer = const value_type*;
using reference = const value_type&;
iterator(wrapped init_curr) :
curr(init_curr),
next(init_curr != wrapped() ? ++init_curr : wrapped())
{
}
iterator& operator++()
{
curr = next;
if (next != wrapped()) {
++next;
}
return *this;
}
iterator operator++(int)
{
iterator tmp(*this);
operator++();
return tmp;
}
bool operator==(const iterator& rhs) const
{
return curr == rhs.curr;
}
bool operator!=(const iterator& rhs) const
{
return curr != rhs.curr;
}
T& operator*()
{
return *curr;
}
};
} // namespace red
#include "pop-visibility.h"
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