qt-everywhere-src-5.15.1/qtbase/src/corelib/tools/qcontainertools_impl.h

/****************************************************************************
**
** Copyright (C) 2018 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com>
** Copyright (C) 2018 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
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#if 0
#pragma qt_sync_skip_header_check
#pragma qt_sync_stop_processing
#endif

#ifndef QCONTAINERTOOLS_IMPL_H
#define QCONTAINERTOOLS_IMPL_H

#include <QtCore/qglobal.h>
#include <iterator>

QT_BEGIN_NAMESPACE

namespace QtPrivate
{
template <typename Iterator>
using IfIsInputIterator = typename std::enable_if<
    std::is_convertible<typename std::iterator_traits<Iterator>::iterator_category, std::input_iterator_tag>::value,
    bool>::type;

template <typename Iterator>
using IfIsForwardIterator = typename std::enable_if<
    std::is_convertible<typename std::iterator_traits<Iterator>::iterator_category, std::forward_iterator_tag>::value,
    bool>::type;

template <typename Iterator>
using IfIsNotForwardIterator = typename std::enable_if<
    !std::is_convertible<typename std::iterator_traits<Iterator>::iterator_category, std::forward_iterator_tag>::value,
    bool>::type;

template <typename Container,
          typename InputIterator,
          IfIsNotForwardIterator<InputIterator> = true>
void reserveIfForwardIterator(Container *, InputIterator, InputIterator)
{
}

template <typename Container,
          typename ForwardIterator,
          IfIsForwardIterator<ForwardIterator> = true>
void reserveIfForwardIterator(Container *c, ForwardIterator f, ForwardIterator l)
{
    c->reserve(static_cast<typename Container::size_type>(std::distance(f, l)));
}

// for detecting expression validity
template <typename ... T>
using void_t = void;

template <typename Iterator, typename = void_t<>>
struct AssociativeIteratorHasKeyAndValue : std::false_type
{
};

template <typename Iterator>
struct AssociativeIteratorHasKeyAndValue<
        Iterator,
        void_t<decltype(std::declval<Iterator &>().key()),
               decltype(std::declval<Iterator &>().value())>
    >
    : std::true_type
{
};

template <typename Iterator, typename = void_t<>, typename = void_t<>>
struct AssociativeIteratorHasFirstAndSecond : std::false_type
{
};

template <typename Iterator>
struct AssociativeIteratorHasFirstAndSecond<
        Iterator,
        void_t<decltype(std::declval<Iterator &>()->first),
               decltype(std::declval<Iterator &>()->second)>
    >
    : std::true_type
{
};

template <typename Iterator>
using IfAssociativeIteratorHasKeyAndValue =
    typename std::enable_if<AssociativeIteratorHasKeyAndValue<Iterator>::value, bool>::type;

template <typename Iterator>
using IfAssociativeIteratorHasFirstAndSecond =
    typename std::enable_if<AssociativeIteratorHasFirstAndSecond<Iterator>::value, bool>::type;

} // namespace QtPrivate

QT_END_NAMESPACE

#endif // QCONTAINERTOOLS_IMPL_H