bobafwata / advanced-c

""" https://ideone.com/qTPPQV if (!(keyBegin < keyEnd))

        return;

    auto nextInterval = --m_map.upper_bound(keyEnd);

    auto inserted1 = m_map.end();

    auto inserted2 = m_map.end();

    assert(nextInterval != m_map.end());

    if (nextInterval->second == val)

        ++nextInterval;

    else if (nextInterval->first < keyEnd)

    {

        const V & nextValue = nextInterval->second;

        ++nextInterval;

        inserted1 = nextInterval = m_map.emplace_hint(nextInterval, keyEnd, nextValue);

    }

    try

    {

        auto prevInterval = nextInterval;

        --prevInterval;

        assert(prevInterval != m_map.end());

        if (keyBegin < prevInterval->first)

            prevInterval = --m_map.upper_bound(keyBegin);

        assert(prevInterval != m_map.end());

        if (!(prevInterval->second == val))

        {

            if (prevInterval->first < keyBegin)

            {

                ++prevInterval;

                inserted2 = prevInterval = m_map.emplace_hint(prevInterval, keyBegin, val);

            }

            else

            {

                auto beforePrev = prevInterval;

                --beforePrev;

                if (beforePrev != m_map.end() && beforePrev->second == val)

                    prevInterval = beforePrev;

                else

                {

                    assert(prevInterval != m_map.end());

                    assert(prevInterval != nextInterval);

                    auto hint = m_map.erase(prevInterval);

                    inserted2 = prevInterval = m_map.emplace_hint(hint, keyBegin, val);

                }

            }

        }

        assert(prevInterval != m_map.end());

        m_map.erase(++prevInterval, nextInterval);

    }

    catch (...)

    {

        if (inserted1 != m_map.end())

            m_map.erase(inserted1);

        if (inserted2 != m_map.end())

            m_map.erase(inserted2);

        throw;

    }

"""