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/* Boost.MultiIndex example of use of multi_index_container::ctor_args_list.
*
* Copyright 2003-2004 Joaqun M Lpez Muoz.
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*
* See http://www.boost.org/libs/multi_index for library home page.
*/
#if !defined(NDEBUG)
#define BOOST_MULTI_INDEX_ENABLE_INVARIANT_CHECKING
#define BOOST_MULTI_INDEX_ENABLE_SAFE_MODE
#endif
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/identity.hpp>
#include <boost/multi_index/ordered_index.hpp>
#include <algorithm>
#include <iostream>
#include <iterator>
using boost::multi_index_container;
using namespace boost::multi_index;
/* modulo_less order numbers according to their division residual.
* For instance, if modulo==10 then 22 is less than 15 as 22%10==2 and
* 15%10==5.
*/
template<typename IntegralType>
struct modulo_less
{
modulo_less(IntegralType m):modulo(m){}
bool operator()(IntegralType x,IntegralType y)const
{
return (x%modulo)<(y%modulo);
}
private:
IntegralType modulo;
};
/* multi_index_container of unsigned ints holding a "natural" index plus
* an ordering based on modulo_less.
*/
typedef multi_index_container<
unsigned int,
indexed_by<
ordered_unique<identity<unsigned int> >,
ordered_non_unique<identity<unsigned int>, modulo_less<unsigned int> >
>
> modulo_indexed_set;
int main()
{
/* define a modulo_indexed_set with modulo==10 */
modulo_indexed_set::ctor_args_list args_list=
boost::make_tuple(
/* ctor_args for index #0 is default constructible */
nth_index<modulo_indexed_set,0>::type::ctor_args(),
/* first parm is key_from_value, second is our sought for key_compare */
boost::make_tuple(identity<unsigned int>(),modulo_less<unsigned int>(10))
);
modulo_indexed_set m(args_list);
/* this could have be written online without the args_list variable,
* left as it is for explanatory purposes. */
/* insert some numbers */
unsigned int numbers[]={0,1,20,40,33,68,11,101,60,34,88,230,21,4,7,17};
const std::size_t numbers_length(sizeof(numbers)/sizeof(numbers[0]));
m.insert(&numbers[0],&numbers[numbers_length]);
/* lists all numbers in order, along with their "equivalence class", that is,
* the equivalent numbers under modulo_less
*/
for(modulo_indexed_set::iterator it=m.begin();it!=m.end();++it){
std::cout<<*it<<" -> ( ";
nth_index<modulo_indexed_set,1>::type::iterator it0,it1;
boost::tie(it0,it1)=get<1>(m).equal_range(*it);
std::copy(it0,it1,std::ostream_iterator<unsigned int>(std::cout," "));
std::cout<<")"<<std::endl;
}
return 0;
}
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