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pilotclient/src/blackmisc/range.h

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/* Copyright (C) 2013
* swift Project Community / Contributors
*
* This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
* directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
* including this file, may be copied, modified, propagated, or distributed except according to the terms
* contained in the LICENSE file.
*/
//! \file
#ifndef BLACKMISC_RANGE_H
#define BLACKMISC_RANGE_H
#include "propertyindexvariantmap.h"
#include "iterator.h"
#include "predicates.h"
#include <QtGlobal>
#include <algorithm>
#include <type_traits>
#include <iterator>
#include <initializer_list>
namespace BlackMisc
{
namespace Private
{
// Trait to exclude std::initializer_list from the overload set of CRange conversion operators using SFINAE.
// Needed to workaround a bug in MSVC whereby it considers the copy constructor and initializer list constructor
// of a container to be ambiguous when converting from a CRange.
//! \private
template <class T> struct is_initializer_list : public std::false_type {};
//! \private
template <class T> struct is_initializer_list<std::initializer_list<T>> : public std::true_type {};
}
template <class> class CRange;
/*!
* Any container class with begin and end iterators can inherit from this CRTP class
* to gain some useful algorithms as member functions.
* \tparam Derived The most derived container class inheriting from this instantiation.
* \tparam CIt the const_iterator of Derived.
*/
template <class Derived, class CIt>
class CRangeBase
{
public:
/*!
* Return a new container generated by applying some transformation function to all elements of this one.
*/
template <class F>
inline auto transform(F function) const
-> CRange<Iterators::TransformIterator<CIt, F>>;
/*!
* \brief Return a copy containing only those elements for which a given predicate returns true.
*/
template <class Predicate>
inline auto findBy(Predicate p) const
-> CRange<Iterators::ConditionalIterator<CIt, Predicate>>;
/*!
* \brief Return a copy containing only those elements matching some particular key/value pair(s).
* \param k0 A pointer to a member function of T.
* \param v0 A value to compare against the value returned by k0.
* \param keysValues Zero or more additional pairs of { pointer to member function of T, value to compare it against }.
*/
template <class K0, class V0, class... KeysValues>
inline auto findBy(K0 k0, V0 v0, KeysValues... keysValues) const
-> CRange<Iterators::ConditionalIterator<CIt, decltype(BlackMisc::Predicates::MemberEqual(k0, v0, keysValues...))>>;
/*!
* \brief Return a copy containing only those elements matching a given value map.
*/
inline auto findBy(CPropertyIndexVariantMap valueMap) const
-> CRange<Iterators::ConditionalIterator<CIt, decltype(BlackMisc::Predicates::Equals(std::move(valueMap)))>>;
/*!
* \brief Return true if there is an element for which a given predicate returns true.
*/
template <class Predicate>
bool containsBy(Predicate p) const
{
return std::any_of(derived().cbegin(), derived().cend(), p);
}
/*!
* \brief Return true if there is an element equal to given object. Uses the most efficient implementation available in the derived container.
*/
template <class T>
bool contains(const T &object) const
{
return derived().find(object) != derived().cend();
}
/*!
* \brief Return a copy containing only those elements matching some particular key/value pair(s).
* \param k0 A pointer to a member function of T.
* \param v0 A value to compare against the value returned by k0.
* \param keysValues Zero or more additional pairs of { pointer to member function of T, value to compare it against }.
*/
template <class K0, class V0, class... KeysValues>
bool contains(K0 k0, V0 v0, KeysValues... keysValues) const
{
return containsBy(BlackMisc::Predicates::MemberEqual(k0, v0, keysValues...));
}
private:
Derived &derived() { return static_cast<Derived &>(*this); }
const Derived &derived() const { return static_cast<const Derived &>(*this); }
};
/*!
* A range is a conceptual container which does not contain any elements of its own,
* but is constructed from a begin iterator and an end iterator of another container.
*
* By using iterator wrappers, it is possible to use CRange to iterate over the results of predicate methods without copying elements.
*
* \warning Remember that the iterators in the range refer to elements in the original container,
* so take care that the original container remains valid and does not invalidate its iterators
* during the lifetime of the range.
*/
template <class I>
class CRange : public CRangeBase<CRange<I>, I>
{
public:
//! STL compatibility
//! @{
typedef typename std::iterator_traits<I>::value_type key_type;
typedef typename std::iterator_traits<I>::value_type value_type;
typedef value_type &reference;
typedef const value_type &const_reference;
typedef value_type *pointer;
typedef const value_type *const_pointer;
typedef I const_iterator;
typedef I iterator;
typedef typename std::iterator_traits<I>::difference_type difference_type;
//! @}
//! Constructor.
CRange(I begin, I end) : m_begin(begin), m_end(end) { check(&begin, &end); }
//! Begin and end iterators.
//! @{
const_iterator begin() const { return m_begin; }
const_iterator cbegin() const { return m_begin; }
const_iterator end() const { return m_end; }
const_iterator cend() const { return m_end; }
//! @}
//! Implicit conversion to any container of value_type which supports push_back. This will copy elements.
template <class T, class = typename std::enable_if<! Private::is_initializer_list<T>::value &&
std::is_convertible<value_type, typename T::value_type>::value>::type>
operator T() const
{
T container;
std::copy(begin(), end(), std::back_inserter(container));
return container;
}
//! Returns true if the range is empty.
//! @{
bool empty() const { return begin() == end(); }
bool isEmpty() const { return empty(); }
//! @}
//! Returns the element at the beginning of the range. Undefined if the range is empty.
const_reference front() const { return *begin(); }
//! Returns the element at the beginning of the range, or a default value if the range is empty.
const_reference frontOrDefault() const
{
static const value_type def{};
return empty() ? def : *begin();
}
//! Returns the element at the beginning of the range, or a default value if the range is empty.
value_type frontOrDefault(value_type def) const
{
return empty() ? def : *begin();
}
private:
I m_begin;
I m_end;
void check(...) {};
template <class I2, class F> void check(Iterators::ConditionalIterator<I2, F> *begin, Iterators::ConditionalIterator<I2, F> *end)
{
begin->checkEnd(*end);
}
};
/*!
* Streaming operators for CRange to qDebug.
*/
//! @{
template <class I>
QDebug operator <<(QDebug d, const CRange<I> &range)
{
for (const auto &v : range) { d << v; }
return d;
}
template <class I>
QNoDebug operator <<(QNoDebug d, const CRange<I> &)
{
return d;
}
//! @}
/*!
* Returns a CRange constructed from begin and end iterators of deduced types.
* \param begin The begin iterator.
* \param end The end iterator, which can be any iterator type convertible to I.
*/
template <class I, class I2>
auto makeRange(I begin, I2 end) -> CRange<I>
{
return { begin, static_cast<I>(end) };
}
/*!
* Returns a CRange constructed from the begin and end iterators of the given container.
*
* The returned CRange may or may not be const, depending on the constness of the container.
*/
template <class T>
auto makeRange(T &&container) -> CRange<decltype(container.begin())>
{
return { container.begin(), container.end() };
}
/*!
* Returns a const CRange constructed from the cbegin and cend iterators of the given container.
*/
template <class T>
auto makeConstRange(T &&container) -> CRange<decltype(container.cbegin())>
{
return { container.cbegin(), container.cend() };
}
/*
* Member functions of CRangeBase template defined out of line, because they depend on CRange etc.
*/
template <class Derived, class CIt>
template <class F>
auto CRangeBase<Derived, CIt>::transform(F function) const
-> CRange<Iterators::TransformIterator<CIt, F>>
{
return makeRange(Iterators::makeTransformIterator(derived().cbegin(), function), derived().cend());
}
template <class Derived, class CIt>
template <class Predicate>
auto CRangeBase<Derived, CIt>::findBy(Predicate p) const
-> CRange<Iterators::ConditionalIterator<CIt, Predicate>>
{
return makeRange(makeConditionalIterator(derived().cbegin(), derived().cend(), p), derived().cend());
}
template <class Derived, class CIt>
template <class K0, class V0, class... KeysValues>
auto CRangeBase<Derived, CIt>::findBy(K0 k0, V0 v0, KeysValues... keysValues) const
-> CRange<Iterators::ConditionalIterator<CIt, decltype(BlackMisc::Predicates::MemberEqual(k0, v0, keysValues...))>>
{
return findBy(BlackMisc::Predicates::MemberEqual(k0, v0, keysValues...));
}
template <class Derived, class CIt>
auto CRangeBase<Derived, CIt>::findBy(CPropertyIndexVariantMap valueMap) const
-> CRange<Iterators::ConditionalIterator<CIt, decltype(BlackMisc::Predicates::Equals(std::move(valueMap)))>>
{
return findBy(BlackMisc::Predicates::Equals(std::move(valueMap)));
}
}
#endif // guard