Re: [Boost-users] Iterator Range, sub range of a desired size

On 10/28/2012 11:40 PM, David Kimmel wrote:

Is there a function in BOOST, given a starting point and a desired size, that returns iterators for a (sub) range?

For example, given: a boost::circular_buffer which contains: 1 2 3 4 5 6 7 8 9 10 a starting point which is an iterator pointing to 5 and finally a desired size which is an int s = 4

The result of which would be iterators producing: 5 6 7 8

A possible implementation might be this (but I was hoping there was a BOOST version since I can't find an STD algorithm)

template <typename Itr> std::pair getWindowDown(Itr begin, Itr end, Itr start, const int windowSize) { // Down first, then up if need be const Itr bottom = (end - start > windowSize) ? (start + windowSize) : (end); const Itr top = (bottom - begin > windowSize) ? (bottom - windowSize) : (begin); return make_pair(top, bottom); }

Thanks,

Would using next or advance work? For example, something like: range = std::make_pair(first, std::next(first, 4)); I can't remember offhand if next is only c++11. If so, there might be a boost::next available. Or alternatively use advance, but it'll require an extra variable to hold the end iterator. Also, from a purely generic standpoint using std::distance is better than end - start. -- Bill