stl_bvector.h

gcc-you can use this code to learn something about gcc, and inquire further into linux,

  
  protected:
    using _Bvector_base<_Alloc>::_M_bit_alloc;
    using _Bvector_base<_Alloc>::_M_deallocate;
    using _Bvector_base<_Alloc>::_M_start;
    using _Bvector_base<_Alloc>::_M_finish;
    using _Bvector_base<_Alloc>::_M_end_of_storage;
  
  protected:
    void _M_initialize(size_type __n) {
      _Bit_type * __q = _M_bit_alloc(__n);
      _M_end_of_storage = __q + (__n + _M_word_bit - 1)/_M_word_bit;
      _M_start = iterator(__q, 0);
      _M_finish = _M_start + difference_type(__n);
    }
    void _M_insert_aux(iterator __position, bool __x) {
      if (_M_finish._M_p != _M_end_of_storage) {
        copy_backward(__position, _M_finish, _M_finish + 1);
        *__position = __x;
        ++_M_finish;
      }
      else {
        size_type __len = size() 
	                  ? 2 * size() : static_cast<size_type>(_M_word_bit);
        _Bit_type * __q = _M_bit_alloc(__len);
        iterator __i = copy(begin(), __position, iterator(__q, 0));
        *__i++ = __x;
        _M_finish = copy(__position, end(), __i);
        _M_deallocate();
        _M_end_of_storage = __q + (__len + _M_word_bit - 1)/_M_word_bit;
        _M_start = iterator(__q, 0);
      }
    }
  
    template <class _InputIterator>
    void _M_initialize_range(_InputIterator __first, _InputIterator __last,
                             input_iterator_tag) {
      _M_start = iterator();
      _M_finish = iterator();
      _M_end_of_storage = 0;
      for ( ; __first != __last; ++__first) 
        push_back(*__first);
    }
  
    template <class _ForwardIterator>
    void _M_initialize_range(_ForwardIterator __first, _ForwardIterator __last,
                             forward_iterator_tag) {
      size_type __n = distance(__first, __last);
      _M_initialize(__n);
      copy(__first, __last, _M_start);
    }
  
    template <class _InputIterator>
    void _M_insert_range(iterator __pos,
                         _InputIterator __first, _InputIterator __last,
                         input_iterator_tag) {
      for ( ; __first != __last; ++__first) {
        __pos = insert(__pos, *__first);
        ++__pos;
      }
    }
  
    template <class _ForwardIterator>
    void _M_insert_range(iterator __position,
                         _ForwardIterator __first, _ForwardIterator __last,
                         forward_iterator_tag) {
      if (__first != __last) {
        size_type __n = distance(__first, __last);
        if (capacity() - size() >= __n) {
          copy_backward(__position, end(), _M_finish + difference_type(__n));
          copy(__first, __last, __position);
          _M_finish += difference_type(__n);
        }
        else {
          size_type __len = size() + max(size(), __n);
          _Bit_type * __q = _M_bit_alloc(__len);
          iterator __i = copy(begin(), __position, iterator(__q, 0));
          __i = copy(__first, __last, __i);
          _M_finish = copy(__position, end(), __i);
          _M_deallocate();
          _M_end_of_storage = __q + (__len + _M_word_bit - 1)/_M_word_bit;
          _M_start = iterator(__q, 0);
        }
      }
    }      
  
  public:
    iterator begin() { return _M_start; }
    const_iterator begin() const { return _M_start; }
    iterator end() { return _M_finish; }
    const_iterator end() const { return _M_finish; }
  
    reverse_iterator rbegin() { return reverse_iterator(end()); }
    const_reverse_iterator rbegin() const { 
      return const_reverse_iterator(end()); 
    }
    reverse_iterator rend() { return reverse_iterator(begin()); }
    const_reverse_iterator rend() const { 
      return const_reverse_iterator(begin()); 
    }
  
    size_type size() const { return size_type(end() - begin()); }
    size_type max_size() const { return size_type(-1); }
    size_type capacity() const {
      return size_type(const_iterator(_M_end_of_storage, 0) - begin());
    }
    bool empty() const { return begin() == end(); }
  
    reference operator[](size_type __n)
      { return *(begin() + difference_type(__n)); }
    const_reference operator[](size_type __n) const
      { return *(begin() + difference_type(__n)); }
  
    void _M_range_check(size_type __n) const {
      if (__n >= this->size())
        __throw_out_of_range("vector<bool>");
    }
  
    reference at(size_type __n)
      { _M_range_check(__n); return (*this)[__n]; }
    const_reference at(size_type __n) const
      { _M_range_check(__n); return (*this)[__n]; }
  
    explicit vector(const allocator_type& __a = allocator_type())
      : _Bvector_base<_Alloc>(__a) {}
  
    vector(size_type __n, bool __value,
              const allocator_type& __a = allocator_type())
      : _Bvector_base<_Alloc>(__a)
    {
      _M_initialize(__n);
      fill(_M_start._M_p, _M_end_of_storage, __value ? ~0 : 0);
    }
  
    explicit vector(size_type __n)
      : _Bvector_base<_Alloc>(allocator_type())
    {
      _M_initialize(__n);
      fill(_M_start._M_p, _M_end_of_storage, 0);
    }
  
    vector(const vector& __x) : _Bvector_base<_Alloc>(__x.get_allocator()) {
      _M_initialize(__x.size());
      copy(__x.begin(), __x.end(), _M_start);
    }
  
    // Check whether it's an integral type.  If so, it's not an iterator.
  
    template <class _Integer>
    void _M_initialize_dispatch(_Integer __n, _Integer __x, __true_type) {
      _M_initialize(__n);
      fill(_M_start._M_p, _M_end_of_storage, __x ? ~0 : 0);
    }
  
    template <class _InputIterator>
    void _M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
                                __false_type) {
      _M_initialize_range(__first, __last, __iterator_category(__first));
    }
  
    template <class _InputIterator>
    vector(_InputIterator __first, _InputIterator __last,
             const allocator_type& __a = allocator_type())
      : _Bvector_base<_Alloc>(__a)
    {
      typedef typename _Is_integer<_InputIterator>::_Integral _Integral;
      _M_initialize_dispatch(__first, __last, _Integral());
    }
      
    ~vector() { }
  
    vector& operator=(const vector& __x) {
      if (&__x == this) return *this;
      if (__x.size() > capacity()) {
        _M_deallocate();
        _M_initialize(__x.size());
      }
      copy(__x.begin(), __x.end(), begin());
      _M_finish = begin() + difference_type(__x.size());
      return *this;
    }
  
    // assign(), a generalized assignment member function.  Two
    // versions: one that takes a count, and one that takes a range.
    // The range version is a member template, so we dispatch on whether
    // or not the type is an integer.
  
    void _M_fill_assign(size_t __n, bool __x) {
      if (__n > size()) {
        fill(_M_start._M_p, _M_end_of_storage, __x ? ~0 : 0);
        insert(end(), __n - size(), __x);
      }
      else {
        erase(begin() + __n, end());
        fill(_M_start._M_p, _M_end_of_storage, __x ? ~0 : 0);
      }
    }
  
    void assign(size_t __n, bool __x) { _M_fill_assign(__n, __x); }
  
    template <class _InputIterator>
    void assign(_InputIterator __first, _InputIterator __last) {
      typedef typename _Is_integer<_InputIterator>::_Integral _Integral;
      _M_assign_dispatch(__first, __last, _Integral());
    }
  
    template <class _Integer>
    void _M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
      { _M_fill_assign((size_t) __n, (bool) __val); }
  
    template <class _InputIter>
    void _M_assign_dispatch(_InputIter __first, _InputIter __last, __false_type)
      { _M_assign_aux(__first, __last, __iterator_category(__first)); }
  
    template <class _InputIterator>
    void _M_assign_aux(_InputIterator __first, _InputIterator __last,
                       input_iterator_tag) {
      iterator __cur = begin();
      for ( ; __first != __last && __cur != end(); ++__cur, ++__first)
        *__cur = *__first;
      if (__first == __last)
        erase(__cur, end());
      else
        insert(end(), __first, __last);
    }
  
    template <class _ForwardIterator>
    void _M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
                       forward_iterator_tag) {
      size_type __len = distance(__first, __last);
      if (__len < size())
        erase(copy(__first, __last, begin()), end());
      else {
        _ForwardIterator __mid = __first;
        advance(__mid, size());
        copy(__first, __mid, begin());
        insert(end(), __mid, __last);
      }
    }    
  
    void reserve(size_type __n) {
      if (__n > this->max_size())
	__throw_length_error("vector::reserve");
      if (this->capacity() < __n) {
        _Bit_type * __q = _M_bit_alloc(__n);
        _M_finish = copy(begin(), end(), iterator(__q, 0));
        _M_deallocate();
        _M_start = iterator(__q, 0);
        _M_end_of_storage = __q + (__n + _M_word_bit - 1)/_M_word_bit;
      }
    }
  
    reference front() { return *begin(); }
    const_reference front() const { return *begin(); }
    reference back() { return *(end() - 1); }
    const_reference back() const { return *(end() - 1); }
    void push_back(bool __x) {
      if (_M_finish._M_p != _M_end_of_storage)
        *_M_finish++ = __x;
      else
        _M_insert_aux(end(), __x);
    }
    void swap(vector<bool, _Alloc>& __x) {
      std::swap(_M_start, __x._M_start);
      std::swap(_M_finish, __x._M_finish);
      std::swap(_M_end_of_storage, __x._M_end_of_storage);
    }

    // [23.2.5]/1, third-to-last entry in synopsis listing
    static void swap(reference __x, reference __y) {
      bool __tmp = __x;
      __x = __y;
      __y = __tmp;
    }

    iterator insert(iterator __position, bool __x = bool()) {
      difference_type __n = __position - begin();
      if (_M_finish._M_p != _M_end_of_storage && __position == end())
        *_M_finish++ = __x;
      else
        _M_insert_aux(__position, __x);
      return begin() + __n;
    }
  
    // Check whether it's an integral type.  If so, it's not an iterator.
  
    template <class _Integer>
    void _M_insert_dispatch(iterator __pos, _Integer __n, _Integer __x,
                            __true_type) {
      _M_fill_insert(__pos, __n, __x);
    }
  
    template <class _InputIterator>
    void _M_insert_dispatch(iterator __pos,
                            _InputIterator __first, _InputIterator __last,
                            __false_type) {
      _M_insert_range(__pos, __first, __last, __iterator_category(__first));
    }
  
    template <class _InputIterator>
    void insert(iterator __position,
                _InputIterator __first, _InputIterator __last) {
      typedef typename _Is_integer<_InputIterator>::_Integral _Integral;
      _M_insert_dispatch(__position, __first, __last, _Integral());
    }
  
    void _M_fill_insert(iterator __position, size_type __n, bool __x) {
      if (__n == 0) return;
      if (capacity() - size() >= __n) {
        copy_backward(__position, end(), _M_finish + difference_type(__n));
        fill(__position, __position + difference_type(__n), __x);
        _M_finish += difference_type(__n);
      }
      else {
        size_type __len = size() + max(size(), __n);
        _Bit_type * __q = _M_bit_alloc(__len);
        iterator __i = copy(begin(), __position, iterator(__q, 0));
        fill_n(__i, __n, __x);
        _M_finish = copy(__position, end(), __i + difference_type(__n));
        _M_deallocate();
        _M_end_of_storage = __q + (__len + _M_word_bit - 1)/_M_word_bit;
        _M_start = iterator(__q, 0);
      }
    }
  
    void insert(iterator __position, size_type __n, bool __x) {
      _M_fill_insert(__position, __n, __x);
    }
  
    void pop_back() { --_M_finish; }
    iterator erase(iterator __position) {
      if (__position + 1 != end())
        copy(__position + 1, end(), __position);
        --_M_finish;
      return __position;
    }
    iterator erase(iterator __first, iterator __last) {
      _M_finish = copy(__last, end(), __first);
      return __first;
    }
    void resize(size_type __new_size, bool __x = bool()) {
      if (__new_size < size()) 
        erase(begin() + difference_type(__new_size), end());
      else
        insert(end(), __new_size - size(), __x);
    }
    void flip() {
      for (_Bit_type * __p = _M_start._M_p; __p != _M_end_of_storage; ++__p)
        *__p = ~*__p;
    }
  
    void clear() { erase(begin(), end()); }
  };

// This typedef is non-standard.  It is provided for backward compatibility.
typedef vector<bool, __alloc> bit_vector;

} // namespace std 

#endif /* __GLIBCPP_INTERNAL_BVECTOR_H */

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