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<Itr, Itr> 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
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