static I sized_impl()

in include/range/v3/algorithm/search_n.hpp [53:86]

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

            static I sized_impl(I const begin_, S end, D const d_, D count,
                V const &val, C &pred, P &proj)
            {
                D d = d_; // always the distance from begin to end
                auto begin = uncounted(begin_);
                while(true)
                {
                    // Find begin element in sequence 1 that matches val, with a mininum of loop checks
                    while(true)
                    {
                        if(d < count)  // return the end if we've run out of room
                            return ranges::next(recounted(begin_, std::move(begin), d_ - d), std::move(end));
                        if(pred(proj(*begin), val))
                            break;
                        ++begin;
                        --d;
                    }
                    // *begin matches val, now match elements after here
                    auto m = begin;
                    D c = 0;
                    while(true)
                    {
                        if(++c == count)  // If pattern exhausted, begin is the answer (works for 1 element pattern)
                            return recounted(begin_, std::move(begin), d_ - d);
                        ++m;  // No need to check, we know we have room to match successfully
                        if(!pred(proj(*m), val))  // if there is a mismatch, restart with a new begin
                        {
                            begin = next(std::move(m));
                            d -= (c+1);
                            break;
                        }  // else there is a match, check next elements
                    }
                }
            }