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

   1 // The template and inlines for the -*- C++ -*- slice_array class.
   2
   3 // Copyright (C) 1997-2017 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 /** @file bits/slice_array.h
  26  *  This is an internal header file, included by other library headers.
  27  *  Do not attempt to use it directly. @headername{valarray}
  28  */
  29
  30 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
  31
  32 #ifndef _SLICE_ARRAY_H
  33 #define _SLICE_ARRAY_H 1
  34
  35 #pragma GCC system_header
  36
  37 namespace std _GLIBCXX_VISIBILITY(default)
  38 {
  39 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  40
  41   /**
  42    * @addtogroup numeric_arrays
  43    * @{
  44    */
  45
  46   /**
  47    *  @brief  Class defining one-dimensional subset of an array.
  48    *
  49    *  The slice class represents a one-dimensional subset of an array,
  50    *  specified by three parameters: start offset, size, and stride.  The
  51    *  start offset is the index of the first element of the array that is part
  52    *  of the subset.  The size is the total number of elements in the subset.
  53    *  Stride is the distance between each successive array element to include
  54    *  in the subset.
  55    *
  56    *  For example, with an array of size 10, and a slice with offset 1, size 3
  57    *  and stride 2, the subset consists of array elements 1, 3, and 5.
  58    */
  59   class slice
  60   {
  61   public:
  62     ///  Construct an empty slice.
  63     slice();
  64
  65     /**
  66      *  @brief  Construct a slice.
  67      *
  68      *  @param  __o  Offset in array of first element.
  69      *  @param  __d  Number of elements in slice.
  70      *  @param  __s  Stride between array elements.
  71      */
  72     slice(size_t __o, size_t __d, size_t __s);
  73
  74     ///  Return array offset of first slice element.
  75     size_t start() const;
  76     ///  Return size of slice.
  77     size_t size() const;
  78     ///  Return array stride of slice.
  79     size_t stride() const;
  80
  81   private:
  82     size_t _M_off;                      // offset
  83     size_t _M_sz;                       // size
  84     size_t _M_st;                       // stride unit
  85   };
  86
  87   // _GLIBCXX_RESOLVE_LIB_DEFECTS
  88   // 543. valarray slice default constructor
  89   inline
  90   slice::slice()
  91   : _M_off(0), _M_sz(0), _M_st(0) {}
  92
  93   inline
  94   slice::slice(size_t __o, size_t __d, size_t __s)
  95   : _M_off(__o), _M_sz(__d), _M_st(__s) {}
  96
  97   inline size_t
  98   slice::start() const
  99   { return _M_off; }
 100
 101   inline size_t
 102   slice::size() const
 103   { return _M_sz; }
 104
 105   inline size_t
 106   slice::stride() const
 107   { return _M_st; }
 108
 109   /**
 110    *  @brief  Reference to one-dimensional subset of an array.
 111    *
 112    *  A slice_array is a reference to the actual elements of an array
 113    *  specified by a slice.  The way to get a slice_array is to call
 114    *  operator[](slice) on a valarray.  The returned slice_array then permits
 115    *  carrying operations out on the referenced subset of elements in the
 116    *  original valarray.  For example, operator+=(valarray) will add values
 117    *  to the subset of elements in the underlying valarray this slice_array
 118    *  refers to.
 119    *
 120    *  @param  Tp  Element type.
 121    */
 122   template<typename _Tp>
 123     class slice_array
 124     {
 125     public:
 126       typedef _Tp value_type;
 127
 128       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 129       // 253. valarray helper functions are almost entirely useless
 130
 131       ///  Copy constructor.  Both slices refer to the same underlying array.
 132       slice_array(const slice_array&);
 133
 134       ///  Assignment operator.  Assigns slice elements to corresponding
 135       ///  elements of @a a.
 136       slice_array& operator=(const slice_array&);
 137
 138       ///  Assign slice elements to corresponding elements of @a v.
 139       void operator=(const valarray<_Tp>&) const;
 140       ///  Multiply slice elements by corresponding elements of @a v.
 141       void operator*=(const valarray<_Tp>&) const;
 142       ///  Divide slice elements by corresponding elements of @a v.
 143       void operator/=(const valarray<_Tp>&) const;
 144       ///  Modulo slice elements by corresponding elements of @a v.
 145       void operator%=(const valarray<_Tp>&) const;
 146       ///  Add corresponding elements of @a v to slice elements.
 147       void operator+=(const valarray<_Tp>&) const;
 148       ///  Subtract corresponding elements of @a v from slice elements.
 149       void operator-=(const valarray<_Tp>&) const;
 150       ///  Logical xor slice elements with corresponding elements of @a v.
 151       void operator^=(const valarray<_Tp>&) const;
 152       ///  Logical and slice elements with corresponding elements of @a v.
 153       void operator&=(const valarray<_Tp>&) const;
 154       ///  Logical or slice elements with corresponding elements of @a v.
 155       void operator|=(const valarray<_Tp>&) const;
 156       ///  Left shift slice elements by corresponding elements of @a v.
 157       void operator<<=(const valarray<_Tp>&) const;
 158       ///  Right shift slice elements by corresponding elements of @a v.
 159       void operator>>=(const valarray<_Tp>&) const;
 160       ///  Assign all slice elements to @a t.
 161       void operator=(const _Tp &) const;
 162       //        ~slice_array ();
 163
 164       template<class _Dom>
 165         void operator=(const _Expr<_Dom, _Tp>&) const;
 166       template<class _Dom>
 167         void operator*=(const _Expr<_Dom, _Tp>&) const;
 168       template<class _Dom>
 169         void operator/=(const _Expr<_Dom, _Tp>&) const;
 170       template<class _Dom>
 171         void operator%=(const _Expr<_Dom, _Tp>&) const;
 172       template<class _Dom>
 173         void operator+=(const _Expr<_Dom, _Tp>&) const;
 174       template<class _Dom>
 175         void operator-=(const _Expr<_Dom, _Tp>&) const;
 176       template<class _Dom>
 177         void operator^=(const _Expr<_Dom, _Tp>&) const;
 178       template<class _Dom>
 179         void operator&=(const _Expr<_Dom, _Tp>&) const;
 180       template<class _Dom>
 181         void operator|=(const _Expr<_Dom, _Tp>&) const;
 182       template<class _Dom>
 183         void operator<<=(const _Expr<_Dom, _Tp>&) const;
 184       template<class _Dom>
 185         void operator>>=(const _Expr<_Dom, _Tp>&) const;
 186
 187     private:
 188       friend class valarray<_Tp>;
 189       slice_array(_Array<_Tp>, const slice&);
 190
 191       const size_t      _M_sz;
 192       const size_t      _M_stride;
 193       const _Array<_Tp> _M_array;
 194
 195       // not implemented
 196       slice_array();
 197     };
 198
 199   template<typename _Tp>
 200     inline
 201     slice_array<_Tp>::slice_array(_Array<_Tp> __a, const slice& __s)
 202     : _M_sz(__s.size()), _M_stride(__s.stride()),
 203       _M_array(__a.begin() + __s.start()) {}
 204
 205   template<typename _Tp>
 206     inline
 207     slice_array<_Tp>::slice_array(const slice_array<_Tp>& a)
 208     : _M_sz(a._M_sz), _M_stride(a._M_stride), _M_array(a._M_array) {}
 209
 210   //    template<typename _Tp>
 211   //    inline slice_array<_Tp>::~slice_array () {}
 212
 213   template<typename _Tp>
 214     inline slice_array<_Tp>&
 215     slice_array<_Tp>::operator=(const slice_array<_Tp>& __a)
 216     {
 217       std::__valarray_copy(__a._M_array, __a._M_sz, __a._M_stride,
 218                            _M_array, _M_stride);
 219       return *this;
 220     }
 221
 222   template<typename _Tp>
 223     inline void
 224     slice_array<_Tp>::operator=(const _Tp& __t) const
 225     { std::__valarray_fill(_M_array, _M_sz, _M_stride, __t); }
 226
 227   template<typename _Tp>
 228     inline void
 229     slice_array<_Tp>::operator=(const valarray<_Tp>& __v) const
 230     { std::__valarray_copy(_Array<_Tp>(__v), _M_array, _M_sz, _M_stride); }
 231
 232   template<typename _Tp>
 233   template<class _Dom>
 234     inline void
 235     slice_array<_Tp>::operator=(const _Expr<_Dom,_Tp>& __e) const
 236     { std::__valarray_copy(__e, _M_sz, _M_array, _M_stride); }
 237
 238 #undef _DEFINE_VALARRAY_OPERATOR
 239 #define _DEFINE_VALARRAY_OPERATOR(_Op,_Name)                            \
 240   template<typename _Tp>                                                \
 241     inline void                                                         \
 242     slice_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const   \
 243     {                                                                   \
 244       _Array_augmented_##_Name(_M_array, _M_sz, _M_stride, _Array<_Tp>(__v));\
 245     }                                                                   \
 246                                                                         \
 247   template<typename _Tp>                                                \
 248     template<class _Dom>                                                \
 249       inline void                                                       \
 250       slice_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
 251       {                                                                 \
 252           _Array_augmented_##_Name(_M_array, _M_stride, __e, _M_sz);    \
 253       }
 254
 255
 256 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
 257 _DEFINE_VALARRAY_OPERATOR(/, __divides)
 258 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
 259 _DEFINE_VALARRAY_OPERATOR(+, __plus)
 260 _DEFINE_VALARRAY_OPERATOR(-, __minus)
 261 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
 262 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
 263 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
 264 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
 265 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
 266
 267 #undef _DEFINE_VALARRAY_OPERATOR
 268
 269   // @} group numeric_arrays
 270
 271 _GLIBCXX_END_NAMESPACE_VERSION
 272 } // namespace
 273
 274 #endif /* _SLICE_ARRAY_H */