_algo.c

来自「stl的源码」· C语言 代码 · 共 1,735 行 · 第 1/5 页

template <class _BidirectionalIter, class _Predicate>
_STLP_INLINE_LOOP _BidirectionalIter __partition(_BidirectionalIter __first,
                                                 _BidirectionalIter __last,
                                                 _Predicate __pred,
                                                 const bidirectional_iterator_tag &) {
  for (;;) {
    for (;;) {
      if (__first == __last)
        return __first;
      else if (__pred(*__first))
        ++__first;
      else
        break;
    }
    --__last;
    for (;;) {
      if (__first == __last)
        return __first;
      else if (!__pred(*__last))
        --__last;
      else
        break;
    }
    iter_swap(__first, __last);
    ++__first;
  }
}

#if defined (_STLP_NONTEMPL_BASE_MATCH_BUG)
template <class _BidirectionalIter, class _Predicate>
inline
_BidirectionalIter __partition(_BidirectionalIter __first,
                               _BidirectionalIter __last,
                               _Predicate __pred,
                               const random_access_iterator_tag &) {
  return __partition(__first, __last, __pred, bidirectional_iterator_tag());
}
#endif

_STLP_MOVE_TO_STD_NAMESPACE

template <class _ForwardIter, class _Predicate>
_ForwardIter partition(_ForwardIter __first, _ForwardIter __last, _Predicate   __pred) {
  _STLP_DEBUG_CHECK(_STLP_PRIV __check_range(__first, __last))
  return _STLP_PRIV __partition(__first, __last, __pred, _STLP_ITERATOR_CATEGORY(__first, _ForwardIter));
}


/* __pred_of_first: false if we know that __pred(*__first) is false,
 *                  true when we don't know the result of __pred(*__first).
 * __not_pred_of_before_last: true if we know that __pred(*--__last) is true,
 *                            false when we don't know the result of __pred(*--__last).
 */
_STLP_MOVE_TO_PRIV_NAMESPACE

template <class _ForwardIter, class _Predicate, class _Distance>
_ForwardIter __inplace_stable_partition(_ForwardIter __first,
                                        _ForwardIter __last,
                                        _Predicate __pred, _Distance __len,
                                        bool __pred_of_first, bool __pred_of_before_last) {
  if (__len == 1)
    return (__pred_of_first && (__pred_of_before_last || __pred(*__first))) ? __last : __first;
  _ForwardIter __middle = __first;
  _Distance __half_len = __len / 2;
  _STLP_STD::advance(__middle, __half_len);
  return _STLP_PRIV __rotate(_STLP_PRIV __inplace_stable_partition(__first, __middle, __pred, __half_len, __pred_of_first, false),
                             __middle,
                             _STLP_PRIV __inplace_stable_partition(__middle, __last, __pred, __len - __half_len, true, __pred_of_before_last));
}

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,
                                         bool __pred_of_first, bool __pred_of_before_last) {
  if (__len <= __buffer_size) {
    _ForwardIter __result1 = __first;
    _Pointer __result2 = __buffer;
    if ((__first != __last) && (!__pred_of_first || __pred(*__first))) {
      *__result2 = *__first;
      ++__result2; ++__first; --__len;
    }
    for (; __first != __last ; ++__first, --__len) {
      if (((__len == 1) && (__pred_of_before_last || __pred(*__first))) ||
          ((__len != 1) && __pred(*__first))){
        *__result1 = *__first;
        ++__result1;
      }
      else {
        *__result2 = *__first;
        ++__result2;
      }
    }
    _STLP_STD::copy(__buffer, __result2, __result1);
    return __result1;
  }
  else {
    _ForwardIter __middle = __first;
    _Distance __half_len = __len / 2;
    _STLP_STD::advance(__middle, __half_len);
    return _STLP_PRIV __rotate(_STLP_PRIV __stable_partition_adaptive(__first, __middle, __pred,
                                                                      __half_len, __buffer, __buffer_size,
                                                                      __pred_of_first, false),
                               __middle,
                               _STLP_PRIV __stable_partition_adaptive(__middle, __last, __pred,
                                                                      __len - __half_len, __buffer, __buffer_size,
                                                                      true, __pred_of_before_last));
  }
}

template <class _ForwardIter, class _Predicate, class _Tp, class _Distance>
inline _ForwardIter
__stable_partition_aux_aux(_ForwardIter __first, _ForwardIter __last,
                           _Predicate __pred, _Tp*, _Distance*, bool __pred_of_before_last) {
  _Temporary_buffer<_ForwardIter, _Tp> __buf(__first, __last);
  _STLP_MPWFIX_TRY    //*TY 06/01/2000 - they forget to call dtor for _Temporary_buffer if no try/catch block is present
  return (__buf.size() > 0) ?
    __stable_partition_adaptive(__first, __last, __pred,
                                _Distance(__buf.requested_size()),
                                __buf.begin(), __buf.size(),
                                false, __pred_of_before_last)  :
    __inplace_stable_partition(__first, __last, __pred,
                               _Distance(__buf.requested_size()),
                               false, __pred_of_before_last);
  _STLP_MPWFIX_CATCH  //*TY 06/01/2000 - they forget to call dtor for _Temporary_buffer if no try/catch block is present
}

template <class _ForwardIter, class _Predicate>
_ForwardIter
__stable_partition_aux(_ForwardIter __first, _ForwardIter __last, _Predicate __pred,
                       const forward_iterator_tag &) {
  return __stable_partition_aux_aux(__first, __last, __pred,
                                    _STLP_VALUE_TYPE(__first, _ForwardIter),
                                    _STLP_DISTANCE_TYPE(__first, _ForwardIter), false);
}

template <class _BidirectIter, class _Predicate>
_BidirectIter
__stable_partition_aux(_BidirectIter __first, _BidirectIter __last, _Predicate __pred,
                       const bidirectional_iterator_tag &) {
  for (--__last;;) {
    if (__first == __last)
      return __first;
    else if (!__pred(*__last))
      --__last;
    else
      break;
  }
  ++__last;
  //Here we know that __pred(*--__last) is true
  return __stable_partition_aux_aux(__first, __last, __pred,
                                    _STLP_VALUE_TYPE(__first, _BidirectIter),
                                    _STLP_DISTANCE_TYPE(__first, _BidirectIter), true);
}

#if defined (_STLP_NONTEMPL_BASE_MATCH_BUG)
template <class _BidirectIter, class _Predicate>
_BidirectIter
__stable_partition_aux(_BidirectIter __first, _BidirectIter __last, _Predicate __pred,
                       const random_access_iterator_tag &) {
  return __stable_partition_aux(__first, __last, __pred, bidirectional_iterator_tag());
}
#endif

_STLP_MOVE_TO_STD_NAMESPACE

template <class _ForwardIter, class _Predicate>
_ForwardIter
stable_partition(_ForwardIter __first, _ForwardIter __last, _Predicate __pred) {
  _STLP_DEBUG_CHECK(_STLP_PRIV __check_range(__first, __last))
  for (;;) {
    if (__first == __last)
      return __first;
    else if (__pred(*__first))
      ++__first;
    else
      break;
  }
  return _STLP_PRIV __stable_partition_aux(__first, __last, __pred,
                                           _STLP_ITERATOR_CATEGORY(__first, _ForwardIter));
}

_STLP_MOVE_TO_PRIV_NAMESPACE

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

// sort() and its auxiliary functions.
#define __stl_threshold  16

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)) {
    _STLP_VERBOSE_ASSERT(!__comp(*__next, __val), _StlMsg_INVALID_STRICT_WEAK_PREDICATE)
    *__last = *__next;
    __last = __next;
    --__next;
  }
  *__last = __val;
}

template <class _RandomAccessIter, class _Tp, class _Compare>
inline void __linear_insert(_RandomAccessIter __first,
                            _RandomAccessIter __last, _Tp __val, _Compare __comp) {
  //*TY 12/26/1998 - added __val as a paramter
  //  _Tp __val = *__last;        //*TY 12/26/1998 - __val supplied by caller
  if (__comp(__val, *__first)) {
    _STLP_VERBOSE_ASSERT(!__comp(*__first, __val), _StlMsg_INVALID_STRICT_WEAK_PREDICATE)
    copy_backward(__first, __last, __last + 1);
    *__first = __val;
  }
  else
    __unguarded_linear_insert(__last, __val, __comp);
}

template <class _RandomAccessIter, class _Tp, class _Compare>
void __insertion_sort(_RandomAccessIter __first,
                      _RandomAccessIter __last,
                      _Tp *, _Compare __comp) {
  if (__first == __last) return;
  for (_RandomAccessIter __i = __first + 1; __i != __last; ++__i)
    __linear_insert<_RandomAccessIter, _Tp, _Compare>(__first, __i, *__i, __comp);  //*TY 12/26/1998 - supply *__i as __val
}

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<_RandomAccessIter, _Tp, _Compare>(__i, *__i, __comp);
}

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

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, _STLP_VALUE_TYPE(__first,_RandomAccessIter), __comp);
    __unguarded_insertion_sort(__first + __stl_threshold, __last, __comp);
  }
  else
    __insertion_sort(__first, __last, _STLP_VALUE_TYPE(__first,_RandomAccessIter), __comp);
}

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;
  }
}

_STLP_MOVE_TO_STD_NAMESPACE

template <class _RandomAccessIter>
void sort(_RandomAccessIter __first, _RandomAccessIter __last) {
  _STLP_DEBUG_CHECK(_STLP_PRIV __check_range(__first, __last))
  if (__first != __last) {
    _STLP_PRIV __introsort_loop(__first, __last,
                                _STLP_VALUE_TYPE(__first, _RandomAccessIter),
                                _STLP_PRIV __lg(__last - __first) * 2,
                                _STLP_PRIV __less(_STLP_VALUE_TYPE(__first, _RandomAccessIter)));
    _STLP_PRIV __final_insertion_sort(__first, __last,
                                      _STLP_PRIV __less(_STLP_VALUE_TYPE(__first, _RandomAccessIter)));
  }
}

template <class _RandomAccessIter, class _Compare>
void sort(_RandomAccessIter __first, _RandomAccessIter __last, _Compare __comp) {
  _STLP_DEBUG_CHECK(_STLP_PRIV __check_range(__first, __last))
  if (__first != __last) {
    _STLP_PRIV __introsort_loop(__first, __last,
                                _STLP_VALUE_TYPE(__first, _RandomAccessIter),
                                _STLP_PRIV __lg(__last - __first) * 2, __comp);
    _STLP_PRIV __final_insertion_sort(__first, __last, __comp);
  }
}

// stable_sort() and its auxiliary functions.
_STLP_MOVE_TO_PRIV_NAMESPACE

template <class _RandomAccessIter, class _Compare>
void __inplace_stable_sort(_RandomAccessIter __first,
                           _RandomAccessIter __last, _Compare __comp) {
  if (__last - __first < 15) {
    __insertion_sort(__first, __last, _STLP_VALUE_TYPE(__first,_RandomAccessIter), __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, class _Compare>
void __merge_sort_loop(_RandomAccessIter1 __first,
                       _RandomAccessIter1 __last,
                       _RandomAccessIter2 __result, _Distance __step_size,
                       _Compare __comp) {
  _Distance __two_step = 2 * __step_size;