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

   1 // The template and inlines for the -*- C++ -*- slice_array class.
   2
   3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006, 2009,
   4 // 2010  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/slice_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 _SLICE_ARRAY_H
  34 #define _SLICE_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  Class defining one-dimensional subset of an array.
  49    *
  50    *  The slice class represents a one-dimensional subset of an array,
  51    *  specified by three parameters: start offset, size, and stride.  The
  52    *  start offset is the index of the first element of the array that is part
  53    *  of the subset.  The size is the total number of elements in the subset.
  54    *  Stride is the distance between each successive array element to include
  55    *  in the subset.
  56    *
  57    *  For example, with an array of size 10, and a slice with offset 1, size 3
  58    *  and stride 2, the subset consists of array elements 1, 3, and 5.
  59    */
  60   class slice
  61   {
  62   public:
  63     ///  Construct an empty slice.
  64     slice();
  65
  66     /**
  67      *  @brief  Construct a slice.
  68      *
  69      *  @param  o  Offset in array of first element.
  70      *  @param  d  Number of elements in slice.
  71      *  @param  s  Stride between array elements.
  72      */
  73     slice(size_t, size_t, size_t);
  74
  75     ///  Return array offset of first slice element.
  76     size_t start() const;
  77     ///  Return size of slice.
  78     size_t size() const;
  79     ///  Return array stride of slice.
  80     size_t stride() const;
  81
  82   private:
  83     size_t _M_off;                      // offset
  84     size_t _M_sz;                       // size
  85     size_t _M_st;                       // stride unit
  86   };
  87
  88   // _GLIBCXX_RESOLVE_LIB_DEFECTS
  89   // 543. valarray slice default constructor
  90   inline
  91   slice::slice()
  92   : _M_off(0), _M_sz(0), _M_st(0) {}
  93
  94   inline
  95   slice::slice(size_t __o, size_t __d, size_t __s)
  96   : _M_off(__o), _M_sz(__d), _M_st(__s) {}
  97
  98   inline size_t
  99   slice::start() const
 100   { return _M_off; }
 101
 102   inline size_t
 103   slice::size() const
 104   { return _M_sz; }
 105
 106   inline size_t
 107   slice::stride() const
 108   { return _M_st; }
 109
 110   /**
 111    *  @brief  Reference to one-dimensional subset of an array.
 112    *
 113    *  A slice_array is a reference to the actual elements of an array
 114    *  specified by a slice.  The way to get a slice_array is to call
 115    *  operator[](slice) on a valarray.  The returned slice_array then permits
 116    *  carrying operations out on the referenced subset of elements in the
 117    *  original valarray.  For example, operator+=(valarray) will add values
 118    *  to the subset of elements in the underlying valarray this slice_array
 119    *  refers to.
 120    *
 121    *  @param  Tp  Element type.
 122    */
 123   template<typename _Tp>
 124     class slice_array
 125     {
 126     public:
 127       typedef _Tp value_type;
 128
 129       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 130       // 253. valarray helper functions are almost entirely useless
 131
 132       ///  Copy constructor.  Both slices refer to the same underlying array.
 133       slice_array(const slice_array&);
 134
 135       ///  Assignment operator.  Assigns slice elements to corresponding
 136       ///  elements of @a a.
 137       slice_array& operator=(const slice_array&);
 138
 139       ///  Assign slice elements to corresponding elements of @a v.
 140       void operator=(const valarray<_Tp>&) const;
 141       ///  Multiply slice elements by corresponding elements of @a v.
 142       void operator*=(const valarray<_Tp>&) const;
 143       ///  Divide slice elements by corresponding elements of @a v.
 144       void operator/=(const valarray<_Tp>&) const;
 145       ///  Modulo slice elements by corresponding elements of @a v.
 146       void operator%=(const valarray<_Tp>&) const;
 147       ///  Add corresponding elements of @a v to slice elements.
 148       void operator+=(const valarray<_Tp>&) const;
 149       ///  Subtract corresponding elements of @a v from slice elements.
 150       void operator-=(const valarray<_Tp>&) const;
 151       ///  Logical xor slice elements with corresponding elements of @a v.
 152       void operator^=(const valarray<_Tp>&) const;
 153       ///  Logical and slice elements with corresponding elements of @a v.
 154       void operator&=(const valarray<_Tp>&) const;
 155       ///  Logical or slice elements with corresponding elements of @a v.
 156       void operator|=(const valarray<_Tp>&) const;
 157       ///  Left shift slice elements by corresponding elements of @a v.
 158       void operator<<=(const valarray<_Tp>&) const;
 159       ///  Right shift slice elements by corresponding elements of @a v.
 160       void operator>>=(const valarray<_Tp>&) const;
 161       ///  Assign all slice elements to @a t.
 162       void operator=(const _Tp &) const;
 163       //        ~slice_array ();
 164
 165       template<class _Dom>
 166         void operator=(const _Expr<_Dom, _Tp>&) const;
 167       template<class _Dom>
 168         void operator*=(const _Expr<_Dom, _Tp>&) const;
 169       template<class _Dom>
 170         void operator/=(const _Expr<_Dom, _Tp>&) const;
 171       template<class _Dom>
 172         void operator%=(const _Expr<_Dom, _Tp>&) const;
 173       template<class _Dom>
 174         void operator+=(const _Expr<_Dom, _Tp>&) const;
 175       template<class _Dom>
 176         void operator-=(const _Expr<_Dom, _Tp>&) const;
 177       template<class _Dom>
 178         void operator^=(const _Expr<_Dom, _Tp>&) const;
 179       template<class _Dom>
 180         void operator&=(const _Expr<_Dom, _Tp>&) const;
 181       template<class _Dom>
 182         void operator|=(const _Expr<_Dom, _Tp>&) const;
 183       template<class _Dom>
 184         void operator<<=(const _Expr<_Dom, _Tp>&) const;
 185       template<class _Dom>
 186         void operator>>=(const _Expr<_Dom, _Tp>&) const;
 187
 188     private:
 189       friend class valarray<_Tp>;
 190       slice_array(_Array<_Tp>, const slice&);
 191
 192       const size_t      _M_sz;
 193       const size_t      _M_stride;
 194       const _Array<_Tp> _M_array;
 195
 196       // not implemented
 197       slice_array();
 198     };
 199
 200   template<typename _Tp>
 201     inline
 202     slice_array<_Tp>::slice_array(_Array<_Tp> __a, const slice& __s)
 203     : _M_sz(__s.size()), _M_stride(__s.stride()),
 204       _M_array(__a.begin() + __s.start()) {}
 205
 206   template<typename _Tp>
 207     inline
 208     slice_array<_Tp>::slice_array(const slice_array<_Tp>& a)
 209     : _M_sz(a._M_sz), _M_stride(a._M_stride), _M_array(a._M_array) {}
 210
 211   //    template<typename _Tp>
 212   //    inline slice_array<_Tp>::~slice_array () {}
 213
 214   template<typename _Tp>
 215     inline slice_array<_Tp>&
 216     slice_array<_Tp>::operator=(const slice_array<_Tp>& __a)
 217     {
 218       std::__valarray_copy(__a._M_array, __a._M_sz, __a._M_stride,
 219                            _M_array, _M_stride);
 220       return *this;
 221     }
 222
 223   template<typename _Tp>
 224     inline void
 225     slice_array<_Tp>::operator=(const _Tp& __t) const
 226     { std::__valarray_fill(_M_array, _M_sz, _M_stride, __t); }
 227
 228   template<typename _Tp>
 229     inline void
 230     slice_array<_Tp>::operator=(const valarray<_Tp>& __v) const
 231     { std::__valarray_copy(_Array<_Tp>(__v), _M_array, _M_sz, _M_stride); }
 232
 233   template<typename _Tp>
 234   template<class _Dom>
 235     inline void
 236     slice_array<_Tp>::operator=(const _Expr<_Dom,_Tp>& __e) const
 237     { std::__valarray_copy(__e, _M_sz, _M_array, _M_stride); }
 238
 239 #undef _DEFINE_VALARRAY_OPERATOR
 240 #define _DEFINE_VALARRAY_OPERATOR(_Op,_Name)                            \
 241   template<typename _Tp>                                                \
 242     inline void                                                         \
 243     slice_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const   \
 244     {                                                                   \
 245       _Array_augmented_##_Name(_M_array, _M_sz, _M_stride, _Array<_Tp>(__v));\
 246     }                                                                   \
 247                                                                         \
 248   template<typename _Tp>                                                \
 249     template<class _Dom>                                                \
 250       inline void                                                       \
 251       slice_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
 252       {                                                                 \
 253           _Array_augmented_##_Name(_M_array, _M_stride, __e, _M_sz);    \
 254       }
 255
 256
 257 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
 258 _DEFINE_VALARRAY_OPERATOR(/, __divides)
 259 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
 260 _DEFINE_VALARRAY_OPERATOR(+, __plus)
 261 _DEFINE_VALARRAY_OPERATOR(-, __minus)
 262 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
 263 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
 264 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
 265 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
 266 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
 267
 268 #undef _DEFINE_VALARRAY_OPERATOR
 269
 270   // @} group numeric_arrays
 271
 272 _GLIBCXX_END_NAMESPACE_VERSION
 273 } // namespace
 274
 275 #endif /* _SLICE_ARRAY_H */