libstdc++-v3/include/bits/mask_array.h

   1 // The template and inlines for the -*- C++ -*- mask_array class.
   2
   3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2009, 2010,
   4 // 2011 Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  25
  26 /** @file bits/mask_array.h
  27  *  This is an internal header file, included by other library headers.
  28  *  Do not attempt to use it directly. @headername{valarray}
  29  */
  30
  31 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
  32
  33 #ifndef _MASK_ARRAY_H
  34 #define _MASK_ARRAY_H 1
  35
  36 #pragma GCC system_header
  37
  38 namespace std _GLIBCXX_VISIBILITY(default)
  39 {
  40 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  41
  42   /**
  43    * @addtogroup numeric_arrays
  44    * @{
  45    */
  46
  47   /**
  48    *  @brief  Reference to selected subset of an array.
  49    *
  50    *  A mask_array is a reference to the actual elements of an array specified
  51    *  by a bitmask in the form of an array of bool.  The way to get a
  52    *  mask_array is to call operator[](valarray<bool>) on a valarray.  The
  53    *  returned mask_array then permits carrying operations out on the
  54    *  referenced subset of elements in the original valarray.
  55    *
  56    *  For example, if a mask_array is obtained using the array (false, true,
  57    *  false, true) as an argument, the mask array has two elements referring
  58    *  to array[1] and array[3] in the underlying array.
  59    *
  60    *  @param  Tp  Element type.
  61    */
  62   template <class _Tp>
  63     class mask_array
  64     {
  65     public:
  66       typedef _Tp value_type;
  67
  68       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  69       // 253. valarray helper functions are almost entirely useless
  70
  71       ///  Copy constructor.  Both slices refer to the same underlying array.
  72       mask_array (const mask_array&);
  73
  74       ///  Assignment operator.  Assigns elements to corresponding elements
  75       ///  of @a a.
  76       mask_array& operator=(const mask_array&);
  77
  78       void operator=(const valarray<_Tp>&) const;
  79       ///  Multiply slice elements by corresponding elements of @a v.
  80       void operator*=(const valarray<_Tp>&) const;
  81       ///  Divide slice elements by corresponding elements of @a v.
  82       void operator/=(const valarray<_Tp>&) const;
  83       ///  Modulo slice elements by corresponding elements of @a v.
  84       void operator%=(const valarray<_Tp>&) const;
  85       ///  Add corresponding elements of @a v to slice elements.
  86       void operator+=(const valarray<_Tp>&) const;
  87       ///  Subtract corresponding elements of @a v from slice elements.
  88       void operator-=(const valarray<_Tp>&) const;
  89       ///  Logical xor slice elements with corresponding elements of @a v.
  90       void operator^=(const valarray<_Tp>&) const;
  91       ///  Logical and slice elements with corresponding elements of @a v.
  92       void operator&=(const valarray<_Tp>&) const;
  93       ///  Logical or slice elements with corresponding elements of @a v.
  94       void operator|=(const valarray<_Tp>&) const;
  95       ///  Left shift slice elements by corresponding elements of @a v.
  96       void operator<<=(const valarray<_Tp>&) const;
  97       ///  Right shift slice elements by corresponding elements of @a v.
  98       void operator>>=(const valarray<_Tp>&) const;
  99       ///  Assign all slice elements to @a t.
 100       void operator=(const _Tp&) const;
 101
 102         //        ~mask_array ();
 103
 104       template<class _Dom>
 105         void operator=(const _Expr<_Dom,_Tp>&) const;
 106       template<class _Dom>
 107         void operator*=(const _Expr<_Dom,_Tp>&) const;
 108       template<class _Dom>
 109         void operator/=(const _Expr<_Dom,_Tp>&) const;
 110       template<class _Dom>
 111         void operator%=(const _Expr<_Dom,_Tp>&) const;
 112       template<class _Dom>
 113         void operator+=(const _Expr<_Dom,_Tp>&) const;
 114       template<class _Dom>
 115         void operator-=(const _Expr<_Dom,_Tp>&) const;
 116       template<class _Dom>
 117         void operator^=(const _Expr<_Dom,_Tp>&) const;
 118       template<class _Dom>
 119         void operator&=(const _Expr<_Dom,_Tp>&) const;
 120       template<class _Dom>
 121         void operator|=(const _Expr<_Dom,_Tp>&) const;
 122       template<class _Dom>
 123         void operator<<=(const _Expr<_Dom,_Tp>&) const;
 124       template<class _Dom>
 125         void operator>>=(const _Expr<_Dom,_Tp>&) const;
 126
 127     private:
 128       mask_array(_Array<_Tp>, size_t, _Array<bool>);
 129       friend class valarray<_Tp>;
 130
 131       const size_t       _M_sz;
 132       const _Array<bool> _M_mask;
 133       const _Array<_Tp>  _M_array;
 134
 135       // not implemented
 136       mask_array();
 137     };
 138
 139   template<typename _Tp>
 140     inline mask_array<_Tp>::mask_array(const mask_array<_Tp>& a)
 141     : _M_sz(a._M_sz), _M_mask(a._M_mask), _M_array(a._M_array) {}
 142
 143   template<typename _Tp>
 144     inline
 145     mask_array<_Tp>::mask_array(_Array<_Tp> __a, size_t __s, _Array<bool> __m)
 146     : _M_sz(__s), _M_mask(__m), _M_array(__a) {}
 147
 148   template<typename _Tp>
 149     inline mask_array<_Tp>&
 150     mask_array<_Tp>::operator=(const mask_array<_Tp>& __a)
 151     {
 152       std::__valarray_copy(__a._M_array, __a._M_mask,
 153                            _M_sz, _M_array, _M_mask);
 154       return *this;
 155     }
 156
 157   template<typename _Tp>
 158     inline void
 159     mask_array<_Tp>::operator=(const _Tp& __t) const
 160     { std::__valarray_fill(_M_array, _M_sz, _M_mask, __t); }
 161
 162   template<typename _Tp>
 163     inline void
 164     mask_array<_Tp>::operator=(const valarray<_Tp>& __v) const
 165     { std::__valarray_copy(_Array<_Tp>(__v), __v.size(), _M_array, _M_mask); }
 166
 167   template<typename _Tp>
 168     template<class _Ex>
 169       inline void
 170       mask_array<_Tp>::operator=(const _Expr<_Ex, _Tp>& __e) const
 171       { std::__valarray_copy(__e, __e.size(), _M_array, _M_mask); }
 172
 173 #undef _DEFINE_VALARRAY_OPERATOR
 174 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name)                           \
 175   template<typename _Tp>                                                \
 176     inline void                                                         \
 177     mask_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const    \
 178     {                                                                   \
 179       _Array_augmented_##_Name(_M_array, _M_mask,                       \
 180                                _Array<_Tp>(__v), __v.size());           \
 181     }                                                                   \
 182                                                                         \
 183   template<typename _Tp>                                                \
 184     template<class _Dom>                                                \
 185       inline void                                                       \
 186       mask_array<_Tp>::operator _Op##=(const _Expr<_Dom, _Tp>& __e) const\
 187       {                                                                 \
 188         _Array_augmented_##_Name(_M_array, _M_mask, __e, __e.size());   \
 189       }
 190
 191 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
 192 _DEFINE_VALARRAY_OPERATOR(/, __divides)
 193 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
 194 _DEFINE_VALARRAY_OPERATOR(+, __plus)
 195 _DEFINE_VALARRAY_OPERATOR(-, __minus)
 196 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
 197 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
 198 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
 199 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
 200 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
 201
 202 #undef _DEFINE_VALARRAY_OPERATOR
 203
 204   // @} group numeric_arrays
 205
 206 _GLIBCXX_END_NAMESPACE_VERSION
 207 } // namespace
 208
 209 #endif /* _MASK_ARRAY_H */