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pilotclient/src/blackmisc/collection.h

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/* Copyright (C) 2013 VATSIM Community / authors
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*!
\file
*/
#ifndef BLACKMISC_COLLECTION_H
#define BLACKMISC_COLLECTION_H
#include "iterator.h"
#include "containerbase.h"
#include <QScopedPointer>
#include <algorithm>
#include <type_traits>
#include <iterator>
#include <utility>
namespace BlackMisc
{
/*!
* \brief Generic type-erased unsequenced container with value semantics.
* \tparam T the type of elements contained.
*
* Can take any suitable container class as its implementation at runtime.
*/
template <class T>
class CCollection : public CContainerBase<CCollection, T>
{
public:
//! \brief STL compatibility
//! @{
typedef T key_type;
typedef T value_type;
typedef T &reference;
typedef const T &const_reference;
typedef T *pointer;
typedef const T *const_pointer;
typedef typename Iterators::ConstForwardIterator<T> const_iterator;
typedef const_iterator iterator; // can't modify elements in-place
typedef ptrdiff_t difference_type;
typedef int size_type;
//! @}
/*!
* \brief Default constructor.
*/
CCollection() : m_pimpl(new Pimpl<QSet<T>>(QSet<T>())) {}
/*!
* \brief Constructor.
* \tparam C Becomes the collection's implementation type.
* \param c Initial value for the collection; typically empty, but could contain elements.
*/
template <class C> CCollection(C c) : m_pimpl(new Pimpl<C>(std::move(c))) {}
/*!
* \brief Copy constructor.
* \param other
*/
CCollection(const CCollection &other) : m_pimpl(other.pimpl() ? other.pimpl()->clone() : nullptr) {}
/*!
* \brief Move constructor.
* \param other
*/
CCollection(CCollection &&other) : m_pimpl(other.m_pimpl.take()) {}
/*!
* \brief Assignment.
* \tparam C Becomes the collection's new implementation type.
* \param c New value for the collection; typically empty, but could contain elements.
*/
template <class C> CCollection &operator =(C c) { m_pimpl.reset(new Pimpl<C>(std::move(c))); return *this; }
/*!
* \brief Copy assignment.
* \param other
* \return
*/
CCollection &operator =(const CCollection &other) { m_pimpl.reset(other.pimpl() ? other.pimpl()->clone() : nullptr); return *this; }
/*!
* \brief Move assignment.
* \param other
* \return
*/
CCollection &operator =(CCollection && other) { m_pimpl.reset(other.m_pimpl.take()); return *this; }
/*!
* \brief Change the implementation type but keep all the same elements, by copying them into the new implementation.
* \tparam C Becomes the collection's new implementation type.
*/
template <class C> void changeImpl(C = C()) { CCollection c = C(); for (auto i = cbegin(); i != cend(); ++i) c.insert(*i); *this = std::move(c); }
/*!
* \brief Like changeImpl, but uses the implementation type of another collection.
* \param other
* \pre The other collection must be initialized.
*/
void useImplOf(const CCollection &other) { PimplPtr p = other.pimpl()->cloneEmpty(); for (auto i = cbegin(); i != cend(); ++i) p->insert(*i); m_pimpl.reset(p.take()); }
/*!
* \brief Returns iterator at the beginning of the collection.
* \return
*/
iterator begin() { return pimpl() ? pimpl()->begin() : iterator(); }
/*!
* \brief Returns iterator at the beginning of the collection.
* \return
*/
const_iterator begin() const { return pimpl() ? pimpl()->begin() : const_iterator(); }
/*!
* \brief Returns iterator at the beginning of the collection.
* \return
*/
const_iterator cbegin() const { return pimpl() ? pimpl()->cbegin() : const_iterator(); }
/*!
* \brief Returns iterator one past the end of the collection.
* \return
*/
iterator end() { return pimpl() ? pimpl()->end() : iterator(); }
/*!
* \brief Returns iterator one past the end of the collection.
* \return
*/
const_iterator end() const { return pimpl() ? pimpl()->end() : const_iterator(); }
/*!
* \brief Returns iterator one past the end of the collection.
* \return
*/
const_iterator cend() const { return pimpl() ? pimpl()->cend() : const_iterator(); }
/*!
* \brief Swap this collection with another.
* \param other
*/
void swap(CCollection &other) { m_pimpl.swap(other.m_pimpl); }
/*!
* \brief Returns number of elements in the collection.
* \return
*/
size_type size() const { return pimpl() ? pimpl()->size() : 0; }
/*!
* \brief Returns true if the collection is empty.
* \return
*/
bool empty() const { return pimpl() ? pimpl()->empty() : true; }
/*!
* \brief Synonym for empty.
* \return
*/
bool isEmpty() const { return empty(); }
/*!
* \brief Removes all elements in the collection.
*/
void clear() { if (pimpl()) pimpl()->clear(); }
/*!
* \brief Inserts an element into the collection.
* \param value
* \return An iterator to the position where value was inserted.
* \pre The collection must be initialized.
*/
iterator insert(const T &value) { Q_ASSERT(pimpl()); return pimpl()->insert(value); }
/*!
* \brief Synonym for insert.
* \param value
* \return An iterator to the position where value was inserted.
* \pre The collection must be initialized.
*/
iterator push_back(const T &value) { return insert(value); }
/*!
* \brief Remove the element pointed to by the given iterator.
* \param pos
* \return An iterator to the position of the next element after the one removed.
* \pre The collection must be initialized.
*/
iterator erase(iterator pos) { Q_ASSERT(pimpl()); return pimpl()->erase(pos); }
/*!
* \brief Remove the range of elements between two iterators.
* \param it1
* \param it2
* \return An iterator to the position of the next element after the one removed.
* \pre The sequence must be initialized.
*/
iterator erase(iterator it1, iterator it2) { Q_ASSERT(pimpl()); return pimpl()->erase(it1, it2); }
/*!
* \brief Test for equality.
* \param other
* \return
* \todo Improve inefficient implementation.
*/
bool operator ==(const CCollection &other) const { return (empty() && other.empty()) ? true : (size() != other.size() ? false : *pimpl() == *other.pimpl()); }
/*!
* \brief Test for inequality.
* \param other
* \return
* \todo Improve inefficient implementation.
*/
bool operator !=(const CCollection &other) const { return !(*this == other); }
private:
class PimplBase
{
public:
virtual ~PimplBase() {}
virtual PimplBase *clone() const = 0;
virtual PimplBase *cloneEmpty() const = 0;
virtual iterator begin() = 0;
virtual const_iterator begin() const = 0;
virtual const_iterator cbegin() const = 0;
virtual iterator end() = 0;
virtual const_iterator end() const = 0;
virtual const_iterator cend() const = 0;
virtual size_type size() const = 0;
virtual bool empty() const = 0;
virtual void clear() = 0;
virtual iterator insert(const T &value) = 0;
virtual iterator erase(iterator pos) = 0;
virtual iterator erase(iterator it1, iterator it2) = 0;
virtual bool operator ==(const PimplBase &other) const = 0;
protected:
// using SFINAE to choose whether to implement insert() in terms of either push_back() or insert(), depending on which is available
// https://groups.google.com/forum/#!original/comp.lang.c++.moderated/T3x6lvmvvkQ/mfY5VTDJ--UJ
class yes { char x; }; class no { yes x[2]; }; template <class X, X V> struct typecheck {};
struct base { void push_back(); }; template <class C> struct derived : public C, public base {};
static yes hasPushHelper(...); template <class D> static no hasPushHelper(D *, typecheck<void (base::*)(), &D::push_back> * = 0);
template <class C> struct hasPush : public std::integral_constant<bool, sizeof(hasPushHelper((derived<C>*)0)) == sizeof(yes)> {};
template <class C> static iterator insertImpl(typename std::enable_if< hasPush<C>::value, C>::type &c, const T &value) { c.push_back(value); return c.end() - 1; }
template <class C> static iterator insertImpl(typename std::enable_if < !hasPush<C>::value, C >::type &c, const T &value) { return c.insert(value); }
};
template <class C> class Pimpl : public PimplBase
{
public:
static_assert(std::is_same<T, typename C::value_type>::value, "CCollection must be initialized from a container with the same value_type.");
Pimpl(C &&c) : m_impl(std::move(c)) {}
PimplBase *clone() const { return new Pimpl(*this); }
PimplBase *cloneEmpty() const { return new Pimpl(C()); }
iterator begin() { return m_impl.begin(); }
const_iterator begin() const { return m_impl.cbegin(); }
const_iterator cbegin() const { return m_impl.cbegin(); }
iterator end() { return m_impl.end(); }
const_iterator end() const { return m_impl.cend(); }
const_iterator cend() const { return m_impl.cend(); }
size_type size() const { return m_impl.size(); }
bool empty() const { return m_impl.empty(); }
void clear() { m_impl.clear(); }
iterator insert(const T &value) { return PimplBase::insertImpl<C>(m_impl, value); }
iterator erase(iterator pos) { return m_impl.erase(*static_cast<const typename C::iterator *>(pos.getImpl())); }
iterator erase(iterator it1, iterator it2) { return m_impl.erase(*static_cast<const typename C::iterator *>(it1.getImpl(), it2.getImpl())); }
bool operator ==(const PimplBase &other) const { Pimpl copy = C(); for (auto i = other.cbegin(); i != other.cend(); ++i) copy.insert(*i); return m_impl == copy.m_impl; }
private:
C m_impl;
};
typedef QScopedPointer<PimplBase> PimplPtr;
PimplPtr m_pimpl;
// using these methods to access m_pimpl.data() eases the cognitive burden of correctly forwarding const
PimplBase *pimpl() { return m_pimpl.data(); }
const PimplBase *pimpl() const { return m_pimpl.data(); }
};
} //namespace BlackMisc
Q_DECLARE_METATYPE(BlackMisc::CCollection<int>)
Q_DECLARE_METATYPE(BlackMisc::CCollection<uint>)
Q_DECLARE_METATYPE(BlackMisc::CCollection<qlonglong>)
Q_DECLARE_METATYPE(BlackMisc::CCollection<qulonglong>)
// CCollection<double> not instantiated because QSet<double> is not supported due to hashing constraints
#endif // guard