qalgorithms.h

QT 开发环境里面一个很重要的文件

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#ifndef QALGORITHMS_H
#define QALGORITHMS_H

#include <QtCore/qglobal.h>

QT_BEGIN_HEADER

QT_MODULE(Core)

/*
    Warning: The contents of QAlgorithmsPrivate is not a part of the public Qt API
    and may be changed from version to version or even be completely removed.
*/
namespace QAlgorithmsPrivate {

template <typename RandomAccessIterator, typename T, typename LessThan>
Q_OUTOFLINE_TEMPLATE void qSortHelper(RandomAccessIterator start, RandomAccessIterator end, const T &t, LessThan lessThan);
template <typename RandomAccessIterator, typename T>
inline void qSortHelper(RandomAccessIterator begin, RandomAccessIterator end, const T &dummy);

template <typename RandomAccessIterator, typename T, typename LessThan>
Q_OUTOFLINE_TEMPLATE void qStableSortHelper(RandomAccessIterator start, RandomAccessIterator end, const T &t, LessThan lessThan);
template <typename RandomAccessIterator, typename T>
inline void qStableSortHelper(RandomAccessIterator, RandomAccessIterator, const T &);

template <typename RandomAccessIterator, typename T, typename LessThan>
Q_OUTOFLINE_TEMPLATE RandomAccessIterator qLowerBoundHelper(RandomAccessIterator begin, RandomAccessIterator end, const T &value, LessThan lessThan);
template <typename RandomAccessIterator, typename T, typename LessThan>
Q_OUTOFLINE_TEMPLATE RandomAccessIterator qUpperBoundHelper(RandomAccessIterator begin, RandomAccessIterator end, const T &value, LessThan lessThan);
template <typename RandomAccessIterator, typename T, typename LessThan>
Q_OUTOFLINE_TEMPLATE RandomAccessIterator qBinaryFindHelper(RandomAccessIterator begin, RandomAccessIterator end, const T &value, LessThan lessThan);

}

template <typename InputIterator, typename OutputIterator>
inline OutputIterator qCopy(InputIterator begin, InputIterator end, OutputIterator dest)
{
    while (begin != end)
        *dest++ = *begin++;
    return dest;
}

template <typename BiIterator1, typename BiIterator2>
inline BiIterator2 qCopyBackward(BiIterator1 begin, BiIterator1 end, BiIterator2 dest)
{
    while (begin != end)
        *--dest = *--end;
    return dest;
}

template <typename InputIterator1, typename InputIterator2>
inline bool qEqual(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2)
{
    for (; first1 != last1; ++first1, ++first2)
        if (!(*first1 == *first2))
            return false;
    return true;
}

template <typename ForwardIterator, typename T>
inline void qFill(ForwardIterator first, ForwardIterator last, const T &val)
{
    for (; first != last; ++first)
        *first = val;
}

template <typename Container, typename T>
inline void qFill(Container &container, const T &val)
{
    qFill(container.begin(), container.end(), val);
}

template <typename InputIterator, typename T>
inline InputIterator qFind(InputIterator first, InputIterator last, const T &val)
{
    while (first != last && !(*first == val))
        ++first;
    return first;
}

template <typename Container, typename T>
inline void qFind(const Container &container, const T &val)
{
    qFind(container.constBegin(), container.constEnd(), val);
}

template <typename InputIterator, typename T, typename Size>
inline void qCount(InputIterator first, InputIterator last, const T &value, Size &n)
{
    for (; first != last; ++first)
        if (*first == value)
            ++n;
}

template <typename Container, typename T, typename Size>
inline void qCount(const Container &container, const T &value, Size &n)
{
    qCount(container.constBegin(), container.constEnd(), value, n);
}

template <typename T>
inline void qSwap(T &value1, T &value2)
{
    if (!QTypeInfo<T>::isComplex || QTypeInfo<T>::isLarge || QTypeInfo<T>::isStatic) {
        T t = value1;
        value1 = value2;
        value2 = t;
    } else {
        const void * const t = reinterpret_cast<const void * const &>(value1);
        const_cast<const void *&>(reinterpret_cast<const void * const &>(value1)) =
            reinterpret_cast<const void * const &>(value2);
        const_cast<const void *&>(reinterpret_cast<const void * const &>(value2)) = t;
    }
}

#ifdef qdoc
template <typename T>
LessThan qLess()
{
}

template <typename T>
LessThan qGreater()
{
}
#else
template <typename T>
class qLess
{
public:
    inline bool operator()(const T &t1, const T &t2) const
    {
        return (t1 < t2);
    }
};

template <typename T>
class qGreater
{
public:
    inline bool operator()(const T &t1, const T &t2) const
    {
        return (t2 < t1);
    }
};
#endif

template <typename RandomAccessIterator>
inline void qSort(RandomAccessIterator start, RandomAccessIterator end)
{
    if (start != end)
        QAlgorithmsPrivate::qSortHelper(start, end, *start);
}

template <typename RandomAccessIterator, typename LessThan>
inline void qSort(RandomAccessIterator start, RandomAccessIterator end, LessThan lessThan)
{
    if (start != end)
        QAlgorithmsPrivate::qSortHelper(start, end, *start, lessThan);
}

template<typename Container>
inline void qSort(Container &c)
{
#ifdef Q_CC_BOR
    // Work around Borland 5.5 optimizer bug
    c.detach();
#endif
    if (!c.empty())
        QAlgorithmsPrivate::qSortHelper(c.begin(), c.end(), *c.begin());
}

template <typename RandomAccessIterator>
inline void qStableSort(RandomAccessIterator start, RandomAccessIterator end)
{
    if (start != end)
        QAlgorithmsPrivate::qStableSortHelper(start, end, *start);
}

template <typename RandomAccessIterator, typename LessThan>
inline void qStableSort(RandomAccessIterator start, RandomAccessIterator end, LessThan lessThan)
{
    if (start != end)
        QAlgorithmsPrivate::qStableSortHelper(start, end, *start, lessThan);
}

template<typename Container>
inline void qStableSort(Container &c)
{
#ifdef Q_CC_BOR
    // Work around Borland 5.5 optimizer bug
    c.detach();
#endif
    if (!c.empty())
        QAlgorithmsPrivate::qStableSortHelper(c.begin(), c.end(), *c.begin());
}

template <typename RandomAccessIterator, typename T>
Q_OUTOFLINE_TEMPLATE RandomAccessIterator qLowerBound(RandomAccessIterator begin, RandomAccessIterator end, const T &value)
{
    // Implementation is duplicated from QAlgorithmsPrivate to keep existing code
    // compiling. We have to allow using *begin and value with different types, 
    // and then implementing operator< for those types.
    RandomAccessIterator middle;
    int n = end - begin;
    int half;

    while (n > 0) {
        half = n >> 1;
        middle = begin + half;
        if (*middle < value) {
            begin = middle + 1;
            n -= half + 1;
        } else {
            n = half;
        }
    }
    return begin;
}

template <typename RandomAccessIterator, typename T, typename LessThan>
Q_OUTOFLINE_TEMPLATE RandomAccessIterator qLowerBound(RandomAccessIterator begin, RandomAccessIterator end, const T &value, LessThan lessThan)
{
    return QAlgorithmsPrivate::qLowerBoundHelper(begin, end, value, lessThan);
}

template <typename Container, typename T>
Q_OUTOFLINE_TEMPLATE typename Container::const_iterator qLowerBound(const Container &container, const T &value)
{
    return QAlgorithmsPrivate::qLowerBoundHelper(container.constBegin(), container.constEnd(), value, qLess<T>());
}

template <typename RandomAccessIterator, typename T>