/* file introspectiveSort.h */
          // code by bds, 3/00
#ifndef __INTROSPECTIVESORT__
#define __INTROSPECTIVESORT__

#include <iterator>
#include "iterator_traits"
#include "heapSort.h"
#include "insertionSort.h"
#include "partition.h"

template<class Iterator>
/* 
 We require that class Iterator has pointer arithmetic operations
 and that the unknown class pointed to by dereferencing iterators has 
 operator <= defined.
*/
void
introspectiveSort(Iterator b, Iterator e, bool randomized = false)
{ introSort(b, 
	    e, 
	    static_cast<int>( ceil(2*log(static_cast<double>(e-b))) ), 
	    randomized ); 
}

template<class Iterator>
void
introSort(Iterator b, Iterator e, int d, bool randomized = false)
{
  // The items [*b, *(b+1) .. *e) will be permuted into sorted order.
  // It's quickSort but 
  // uses special handling of small sequences and deep recursion.
  if ((e-b) <= 15) // small sequence threshold. 
    // then zero or one elements -- and that's already sorted.
    insertionSort(b, e); 
  else if (d == 0) // reached recursion-is-too-deep-for-quickSort threshold.
    heapSort(b, e);
  else
  {
    Iterator p = partition(b, e, randomized);
    ++p;
    introSort(b, p, d-1);
    introSort(p, e, d-1);
  }
}

#endif