static tagged_pair impl()

in include/range/v3/algorithm/unique_copy.hpp [46:70]

• 23 lines of code
• 8 McCabe index (conditional complexity)

            static tagged_pair<tag::in(I), tag::out(O)> impl(I begin, S end, O out, C pred_, P proj_,
                concepts::InputIterator*, std::false_type)
            {
                auto &&pred = as_function(pred_);
                auto &&proj = as_function(proj_);
                if(begin != end)
                {
                    // Must save a copy into a local because we will need this value
                    // even after we advance the input iterator.
                    iterator_value_t<I> value = *begin; // This is guaranteed by IndirectlyCopyable
                    *out = value;
                    ++out;
                    while(++begin != end)
                    {
                        auto &&x = *begin;
                        if(!pred(proj(value), proj(x)))
                        {
                            value = (decltype(x) &&) x;
                            *out = value;
                            ++out;
                        }
                    }
                }
                return {begin, out};
            }