/** @file

    $Id$

    $Date$
    $Author$

    @copy © Marc Wäckerlin
    @license LGPL, see file <a href="license.html">COPYING</a>

    $Log$
    Revision 1.1  2004/10/07 09:31:30  marc
    new feature


*/
#ifndef __MRW__SET__HPP__
#define __MRW__SET__HPP__

#include <set>
#include <mrw/exception.hpp>
#include <mrw/string.hpp>

/** @addtogroup StdExt
 */
//@{

/** @brief insert a value in a set

    @code
    std::set<int> test;
    test<<1<<2<<3<<4<<5<<6<<7<<8;
    @endcode

    @throw mrw::invalid_argument, if element is already in set
    @param l a set of values
    @param o a value to be inserted into set @c l
    @pre #include <mrw/set.hpp>
*/
template <typename T, class C, typename A>
std::set<T, C, A>& operator<<(std::set<T, C, A>& l, const T& o)
  throw(std::exception) {
  if (!l.insert(o).second)
    throw mrw::invalid_argument(std::string(__FILE__ ":")+__LINE__+
                                ": std::set<>&"
                                " operator<<(std::set<>&, const T&),"
                                "set element already exists");
  return l;
}

/** @brief extract the first value of a set

    @code
    std::set<int> test;
    test<<1<<2<<3<<4<<5<<6<<7<<8;
    int i1(0), i2(0), i3(0), i4(0);
    test>>i1>>i2>>i3>>i4;
    // now: i1==1 i2==2 i3==3 i4==4 test=={5, 6, 7, 8}
    @endcode

    @param l a set of values
    @param o a value to be extracted from set @c l
    @throw mrw::length_error, if set was empty on entry
    @note when something is extracted from a set, it is removed
    from the set, that means after every shift the set is
    shortened by the shifted element
    @pre #include <mrw/string.hpp>
*/
template <typename T, class C, typename A>
std::set<T, C, A>& operator>>(std::set<T, C, A>& l, T& o)
  throw(std::exception) {
  typename std::set<T, C, A>::iterator it(l.begin());
  if (it==l.end())
    throw mrw::length_error(std::string(__FILE__ ":")+__LINE__+
                            ": std::set<>& operator>>(std::set<>&, T&),"
                            " set is empty");
  o = *it;
  l.erase(it);
  return l;
}

//@}

#endif