stl_algo.h

STL 最新源代码

        return __first;
      else if (__pred(*__first))
        ++__first;
      else
        break;
    --__last;
    while (true)
      if (__first == __last)
        return __first;
      else if (!__pred(*__last))
        --__last;
      else
        break;
    iter_swap(__first, __last);
    ++__first;
  }
}

template <class _ForwardIter, class _Predicate>
inline _ForwardIter partition(_ForwardIter __first,
   			      _ForwardIter __last,
			      _Predicate   __pred) {
  __STL_REQUIRES(_ForwardIter, _Mutable_ForwardIterator);
  __STL_UNARY_FUNCTION_CHECK(_Predicate, bool, 
        typename iterator_traits<_ForwardIter>::value_type);
  return __partition(__first, __last, __pred, __ITERATOR_CATEGORY(__first));
}


template <class _ForwardIter, class _Predicate, class _Distance>
_ForwardIter __inplace_stable_partition(_ForwardIter __first,
                                        _ForwardIter __last,
                                        _Predicate __pred, _Distance __len) {
  if (__len == 1)
    return __pred(*__first) ? __last : __first;
  _ForwardIter __middle = __first;
  advance(__middle, __len / 2);
  return rotate(__inplace_stable_partition(__first, __middle, __pred, 
                                           __len / 2),
                __middle,
                __inplace_stable_partition(__middle, __last, __pred,
                                           __len - __len / 2));
}

template <class _ForwardIter, class _Pointer, class _Predicate, 
          class _Distance>
_ForwardIter __stable_partition_adaptive(_ForwardIter __first,
                                         _ForwardIter __last,
                                         _Predicate __pred, _Distance __len,
                                         _Pointer __buffer,
                                         _Distance __buffer_size) 
{
  if (__len <= __buffer_size) {
    _ForwardIter __result1 = __first;
    _Pointer __result2 = __buffer;
    for ( ; __first != __last ; ++__first)
      if (__pred(*__first)) {
        *__result1 = *__first;
        ++__result1;
      }
      else {
        *__result2 = *__first;
        ++__result2;
      }
    copy(__buffer, __result2, __result1);
    return __result1;
  }
  else {
    _ForwardIter __middle = __first;
    advance(__middle, __len / 2);
    return rotate(__stable_partition_adaptive(
                          __first, __middle, __pred,
                          __len / 2, __buffer, __buffer_size),
                    __middle,
                    __stable_partition_adaptive(
                          __middle, __last, __pred,
                          __len - __len / 2, __buffer, __buffer_size));
  }
}

template <class _ForwardIter, class _Predicate, class _Tp, class _Distance>
inline _ForwardIter
__stable_partition_aux(_ForwardIter __first, _ForwardIter __last, 
                       _Predicate __pred, _Tp*, _Distance*)
{
  _Temporary_buffer<_ForwardIter, _Tp> __buf(__first, __last);
  if (__buf.size() > 0)
    return __stable_partition_adaptive(__first, __last, __pred,
                                       _Distance(__buf.requested_size()),
                                       __buf.begin(), __buf.size());
  else
    return __inplace_stable_partition(__first, __last, __pred, 
                                      _Distance(__buf.requested_size()));
}

template <class _ForwardIter, class _Predicate>
inline _ForwardIter stable_partition(_ForwardIter __first,
                                     _ForwardIter __last, 
                                     _Predicate __pred) {
  __STL_REQUIRES(_ForwardIter, _Mutable_ForwardIterator);
  __STL_UNARY_FUNCTION_CHECK(_Predicate, bool,
      typename iterator_traits<_ForwardIter>::value_type);
  if (__first == __last)
    return __first;
  else
    return __stable_partition_aux(__first, __last, __pred,
                                  __VALUE_TYPE(__first),
                                  __DISTANCE_TYPE(__first));
}

template <class _RandomAccessIter, class _Tp>
_RandomAccessIter __unguarded_partition(_RandomAccessIter __first, 
                                        _RandomAccessIter __last, 
                                        _Tp __pivot) 
{
  while (true) {
    while (*__first < __pivot)
      ++__first;
    --__last;
    while (__pivot < *__last)
      --__last;
    if (!(__first < __last))
      return __first;
    iter_swap(__first, __last);
    ++__first;
  }
}    

template <class _RandomAccessIter, class _Tp, class _Compare>
_RandomAccessIter __unguarded_partition(_RandomAccessIter __first, 
                                        _RandomAccessIter __last, 
                                        _Tp __pivot, _Compare __comp) 
{
  while (true) {
    while (__comp(*__first, __pivot))
      ++__first;
    --__last;
    while (__comp(__pivot, *__last))
      --__last;
    if (!(__first < __last))
      return __first;
    iter_swap(__first, __last);
    ++__first;
  }
}

const int __stl_threshold = 16;

// sort() and its auxiliary functions. 

template <class _RandomAccessIter, class _Tp>
void __unguarded_linear_insert(_RandomAccessIter __last, _Tp __val) {
  _RandomAccessIter __next = __last;
  --__next;
  while (__val < *__next) {
    *__last = *__next;
    __last = __next;
    --__next;
  }
  *__last = __val;
}

template <class _RandomAccessIter, class _Tp, class _Compare>
void __unguarded_linear_insert(_RandomAccessIter __last, _Tp __val, 
                               _Compare __comp) {
  _RandomAccessIter __next = __last;
  --__next;  
  while (__comp(__val, *__next)) {
    *__last = *__next;
    __last = __next;
    --__next;
  }
  *__last = __val;
}

template <class _RandomAccessIter, class _Tp>
inline void __linear_insert(_RandomAccessIter __first, 
                            _RandomAccessIter __last, _Tp*) {
  _Tp __val = *__last;
  if (__val < *__first) {
    copy_backward(__first, __last, __last + 1);
    *__first = __val;
  }
  else
    __unguarded_linear_insert(__last, __val);
}

template <class _RandomAccessIter, class _Tp, class _Compare>
inline void __linear_insert(_RandomAccessIter __first, 
                            _RandomAccessIter __last, _Tp*, _Compare __comp) {
  _Tp __val = *__last;
  if (__comp(__val, *__first)) {
    copy_backward(__first, __last, __last + 1);
    *__first = __val;
  }
  else
    __unguarded_linear_insert(__last, __val, __comp);
}

template <class _RandomAccessIter>
void __insertion_sort(_RandomAccessIter __first, _RandomAccessIter __last) {
  if (__first == __last) return; 
  for (_RandomAccessIter __i = __first + 1; __i != __last; ++__i)
    __linear_insert(__first, __i, __VALUE_TYPE(__first));
}

template <class _RandomAccessIter, class _Compare>
void __insertion_sort(_RandomAccessIter __first,
                      _RandomAccessIter __last, _Compare __comp) {
  if (__first == __last) return;
  for (_RandomAccessIter __i = __first + 1; __i != __last; ++__i)
    __linear_insert(__first, __i, __VALUE_TYPE(__first), __comp);
}

template <class _RandomAccessIter, class _Tp>
void __unguarded_insertion_sort_aux(_RandomAccessIter __first, 
                                    _RandomAccessIter __last, _Tp*) {
  for (_RandomAccessIter __i = __first; __i != __last; ++__i)
    __unguarded_linear_insert(__i, _Tp(*__i));
}

template <class _RandomAccessIter>
inline void __unguarded_insertion_sort(_RandomAccessIter __first, 
                                _RandomAccessIter __last) {
  __unguarded_insertion_sort_aux(__first, __last, __VALUE_TYPE(__first));
}

template <class _RandomAccessIter, class _Tp, class _Compare>
void __unguarded_insertion_sort_aux(_RandomAccessIter __first, 
                                    _RandomAccessIter __last,
                                    _Tp*, _Compare __comp) {
  for (_RandomAccessIter __i = __first; __i != __last; ++__i)
    __unguarded_linear_insert(__i, _Tp(*__i), __comp);
}

template <class _RandomAccessIter, class _Compare>
inline void __unguarded_insertion_sort(_RandomAccessIter __first, 
                                       _RandomAccessIter __last,
                                       _Compare __comp) {
  __unguarded_insertion_sort_aux(__first, __last, __VALUE_TYPE(__first),
                                 __comp);
}

template <class _RandomAccessIter>
void __final_insertion_sort(_RandomAccessIter __first, 
                            _RandomAccessIter __last) {
  if (__last - __first > __stl_threshold) {
    __insertion_sort(__first, __first + __stl_threshold);
    __unguarded_insertion_sort(__first + __stl_threshold, __last);
  }
  else
    __insertion_sort(__first, __last);
}

template <class _RandomAccessIter, class _Compare>
void __final_insertion_sort(_RandomAccessIter __first, 
                            _RandomAccessIter __last, _Compare __comp) {
  if (__last - __first > __stl_threshold) {
    __insertion_sort(__first, __first + __stl_threshold, __comp);
    __unguarded_insertion_sort(__first + __stl_threshold, __last, __comp);
  }
  else
    __insertion_sort(__first, __last, __comp);
}

template <class _Size>
inline _Size __lg(_Size __n) {
  _Size __k;
  for (__k = 0; __n != 1; __n >>= 1) ++__k;
  return __k;
}

template <class _RandomAccessIter, class _Tp, class _Size>
void __introsort_loop(_RandomAccessIter __first,
                      _RandomAccessIter __last, _Tp*,
                      _Size __depth_limit)
{
  while (__last - __first > __stl_threshold) {
    if (__depth_limit == 0) {
      partial_sort(__first, __last, __last);
      return;
    }
    --__depth_limit;
    _RandomAccessIter __cut =
      __unguarded_partition(__first, __last,
                            _Tp(__median(*__first,
                                         *(__first + (__last - __first)/2),
                                         *(__last - 1))));
    __introsort_loop(__cut, __last, (_Tp*) 0, __depth_limit);
    __last = __cut;
  }
}

template <class _RandomAccessIter, class _Tp, class _Size, class _Compare>
void __introsort_loop(_RandomAccessIter __first,
                      _RandomAccessIter __last, _Tp*,
                      _Size __depth_limit, _Compare __comp)
{
  while (__last - __first > __stl_threshold) {
    if (__depth_limit == 0) {
      partial_sort(__first, __last, __last, __comp);
      return;
    }
    --__depth_limit;
    _RandomAccessIter __cut =
      __unguarded_partition(__first, __last,
                            _Tp(__median(*__first,
                                         *(__first + (__last - __first)/2),
                                         *(__last - 1), __comp)),
       __comp);
    __introsort_loop(__cut, __last, (_Tp*) 0, __depth_limit, __comp);
    __last = __cut;
  }
}

template <class _RandomAccessIter>
inline void sort(_RandomAccessIter __first, _RandomAccessIter __last) {
  __STL_REQUIRES(_RandomAccessIter, _Mutable_RandomAccessIterator);
  __STL_REQUIRES(typename iterator_traits<_RandomAccessIter>::value_type,
                 _LessThanComparable);
  if (__first != __last) {
    __introsort_loop(__first, __last,
                     __VALUE_TYPE(__first),
                     __lg(__last - __first) * 2);
    __final_insertion_sort(__first, __last);
  }
}

template <class _RandomAccessIter, class _Compare>
inline void sort(_RandomAccessIter __first, _RandomAccessIter __last,
                 _Compare __comp) {
  __STL_REQUIRES(_RandomAccessIter, _Mutable_RandomAccessIterator);
  __STL_BINARY_FUNCTION_CHECK(_Compare, bool,
       typename iterator_traits<_RandomAccessIter>::value_type,
       typename iterator_traits<_RandomAccessIter>::value_type);
  if (__first != __last) {
    __introsort_loop(__first, __last,
                     __VALUE_TYPE(__first),
                     __lg(__last - __first) * 2,
                     __comp);
    __final_insertion_sort(__first, __last, __comp);
  }
}

// stable_sort() and its auxiliary functions.

template <class _RandomAccessIter>
void __inplace_stable_sort(_RandomAccessIter __first,
                           _RandomAccessIter __last) {
  if (__last - __first < 15) {
    __insertion_sort(__first, __last);
    return;
  }
  _RandomAccessIter __middle = __first + (__last - __first) / 2;
  __inplace_stable_sort(__first, __middle);
  __inplace_stable_sort(__middle, __last);
  __merge_without_buffer(__first, __middle, __last,
                         __middle - __first,
                         __last - __middle);
}

template <class _RandomAccessIter, class _Compare>
void __inplace_stable_sort(_RandomAccessIter __first,
                           _RandomAccessIter __last, _Compare __comp) {
  if (__last - __first < 15) {
    __insertion_sort(__first, __last, __comp);
    return;
  }
  _RandomAccessIter __middle = __first + (__last - __first) / 2;
  __inplace_stable_sort(__first, __middle, __comp);
  __inplace_stable_sort(__middle, __last, __comp);
  __merge_without_buffer(__first, __middle, __last,
                         __middle - __first,
                         __last - __middle,
                         __comp);
}

template <class _RandomAccessIter1, class _RandomAccessIter2,
          class _Distance>
void __merge_sort_loop(_RandomAccessIter1 __first,
                       _RandomAccessIter1 __last, 
                       _RandomAccessIter2 __result, _Distance __step_size) {
  _Distance __two_step = 2 * __step_size;