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 // 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 2, 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 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING.  If not, write to the Free
  19 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  20 // USA.
  21
  22 // As a special exception, you may use this file as part of a free software
  23 // library without restriction.  Specifically, if other files instantiate
  24 // templates or use macros or inline functions from this file, or you compile
  25 // this file and link it with other files to produce an executable, this
  26 // file does not by itself cause the resulting executable to be covered by
  27 // the GNU General Public License.  This exception does not however
  28 // invalidate any other reasons why the executable file might be covered by
  29 // the GNU General Public License.
  30
  31 /** @file slice_array.h
  32  *  This is an internal header file, included by other library headers.
  33  *  You should not attempt to use it directly.
  34  */
  35
  36 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
  37
  38 #ifndef _SLICE_ARRAY_H
  39 #define _SLICE_ARRAY_H 1
  40
  41 #pragma GCC system_header
  42
  43 _GLIBCXX_BEGIN_NAMESPACE(std)
  44
  45   /**
  46    * @addtogroup numeric_arrays
  47    * @{
  48    */
  49
  50   /**
  51    *  @brief  Class defining one-dimensional subset of an array.
  52    *
  53    *  The slice class represents a one-dimensional subset of an array,
  54    *  specified by three parameters: start offset, size, and stride.  The
  55    *  start offset is the index of the first element of the array that is part
  56    *  of the subset.  The size is the total number of elements in the subset.
  57    *  Stride is the distance between each successive array element to include
  58    *  in the subset.
  59    *
  60    *  For example, with an array of size 10, and a slice with offset 1, size 3
  61    *  and stride 2, the subset consists of array elements 1, 3, and 5.
  62    */
  63   class slice
  64   {
  65   public:
  66     ///  Construct an empty slice.
  67     slice();
  68
  69     /**
  70      *  @brief  Construct a slice.
  71      *
  72      *  @param  o  Offset in array of first element.
  73      *  @param  d  Number of elements in slice.
  74      *  @param  s  Stride between array elements.
  75      */
  76     slice(size_t, size_t, size_t);
  77
  78     ///  Return array offset of first slice element.
  79     size_t start() const;
  80     ///  Return size of slice.
  81     size_t size() const;
  82     ///  Return array stride of slice.
  83     size_t stride() const;
  84
  85   private:
  86     size_t _M_off;                      // offset
  87     size_t _M_sz;                       // size
  88     size_t _M_st;                       // stride unit
  89   };
  90
  91   // _GLIBCXX_RESOLVE_LIB_DEFECTS
  92   // 543. valarray slice default constructor
  93   inline
  94   slice::slice()
  95   : _M_off(0), _M_sz(0), _M_st(0) {}
  96
  97   inline
  98   slice::slice(size_t __o, size_t __d, size_t __s)
  99   : _M_off(__o), _M_sz(__d), _M_st(__s) {}
 100
 101   inline size_t
 102   slice::start() const
 103   { return _M_off; }
 104
 105   inline size_t
 106   slice::size() const
 107   { return _M_sz; }
 108
 109   inline size_t
 110   slice::stride() const
 111   { return _M_st; }
 112
 113   /**
 114    *  @brief  Reference to one-dimensional subset of an array.
 115    *
 116    *  A slice_array is a reference to the actual elements of an array
 117    *  specified by a slice.  The way to get a slice_array is to call
 118    *  operator[](slice) on a valarray.  The returned slice_array then permits
 119    *  carrying operations out on the referenced subset of elements in the
 120    *  original valarray.  For example, operator+=(valarray) will add values
 121    *  to the subset of elements in the underlying valarray this slice_array
 122    *  refers to.
 123    *
 124    *  @param  Tp  Element type.
 125    */
 126   template<typename _Tp>
 127     class slice_array
 128     {
 129     public:
 130       typedef _Tp value_type;
 131
 132       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 133       // 253. valarray helper functions are almost entirely useless
 134
 135       ///  Copy constructor.  Both slices refer to the same underlying array.
 136       slice_array(const slice_array&);
 137
 138       ///  Assignment operator.  Assigns slice elements to corresponding
 139       ///  elements of @a a.
 140       slice_array& operator=(const slice_array&);
 141
 142       ///  Assign slice elements to corresponding elements of @a v.
 143       void operator=(const valarray<_Tp>&) const;
 144       ///  Multiply slice elements by corresponding elements of @a v.
 145       void operator*=(const valarray<_Tp>&) const;
 146       ///  Divide slice elements by corresponding elements of @a v.
 147       void operator/=(const valarray<_Tp>&) const;
 148       ///  Modulo slice elements by corresponding elements of @a v.
 149       void operator%=(const valarray<_Tp>&) const;
 150       ///  Add corresponding elements of @a v to slice elements.
 151       void operator+=(const valarray<_Tp>&) const;
 152       ///  Subtract corresponding elements of @a v from slice elements.
 153       void operator-=(const valarray<_Tp>&) const;
 154       ///  Logical xor slice elements with corresponding elements of @a v.
 155       void operator^=(const valarray<_Tp>&) const;
 156       ///  Logical and slice elements with corresponding elements of @a v.
 157       void operator&=(const valarray<_Tp>&) const;
 158       ///  Logical or slice elements with corresponding elements of @a v.
 159       void operator|=(const valarray<_Tp>&) const;
 160       ///  Left shift slice elements by corresponding elements of @a v.
 161       void operator<<=(const valarray<_Tp>&) const;
 162       ///  Right shift slice elements by corresponding elements of @a v.
 163       void operator>>=(const valarray<_Tp>&) const;
 164       ///  Assign all slice elements to @a t.
 165       void operator=(const _Tp &) const;
 166       //        ~slice_array ();
 167
 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       template<class _Dom>
 187         void operator<<=(const _Expr<_Dom, _Tp>&) const;
 188       template<class _Dom>
 189         void operator>>=(const _Expr<_Dom, _Tp>&) const;
 190
 191     private:
 192       friend class valarray<_Tp>;
 193       slice_array(_Array<_Tp>, const slice&);
 194
 195       const size_t      _M_sz;
 196       const size_t      _M_stride;
 197       const _Array<_Tp> _M_array;
 198
 199       // not implemented
 200       slice_array();
 201     };
 202
 203   template<typename _Tp>
 204     inline
 205     slice_array<_Tp>::slice_array(_Array<_Tp> __a, const slice& __s)
 206     : _M_sz(__s.size()), _M_stride(__s.stride()),
 207       _M_array(__a.begin() + __s.start()) {}
 208
 209   template<typename _Tp>
 210     inline
 211     slice_array<_Tp>::slice_array(const slice_array<_Tp>& a)
 212     : _M_sz(a._M_sz), _M_stride(a._M_stride), _M_array(a._M_array) {}
 213
 214   //    template<typename _Tp>
 215   //    inline slice_array<_Tp>::~slice_array () {}
 216
 217   template<typename _Tp>
 218     inline slice_array<_Tp>&
 219     slice_array<_Tp>::operator=(const slice_array<_Tp>& __a)
 220     {
 221       std::__valarray_copy(__a._M_array, __a._M_sz, __a._M_stride,
 222                            _M_array, _M_stride);
 223       return *this;
 224     }
 225
 226   template<typename _Tp>
 227     inline void
 228     slice_array<_Tp>::operator=(const _Tp& __t) const
 229     { std::__valarray_fill(_M_array, _M_sz, _M_stride, __t); }
 230
 231   template<typename _Tp>
 232     inline void
 233     slice_array<_Tp>::operator=(const valarray<_Tp>& __v) const
 234     { std::__valarray_copy(_Array<_Tp>(__v), _M_array, _M_sz, _M_stride); }
 235
 236   template<typename _Tp>
 237   template<class _Dom>
 238     inline void
 239     slice_array<_Tp>::operator=(const _Expr<_Dom,_Tp>& __e) const
 240     { std::__valarray_copy(__e, _M_sz, _M_array, _M_stride); }
 241
 242 #undef _DEFINE_VALARRAY_OPERATOR
 243 #define _DEFINE_VALARRAY_OPERATOR(_Op,_Name)                            \
 244   template<typename _Tp>                                                \
 245     inline void                                                         \
 246     slice_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const   \
 247     {                                                                   \
 248       _Array_augmented_##_Name(_M_array, _M_sz, _M_stride, _Array<_Tp>(__v));\
 249     }                                                                   \
 250                                                                         \
 251   template<typename _Tp>                                                \
 252     template<class _Dom>                                                \
 253       inline void                                                       \
 254       slice_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
 255       {                                                                 \
 256           _Array_augmented_##_Name(_M_array, _M_stride, __e, _M_sz);    \
 257       }
 258
 259
 260 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
 261 _DEFINE_VALARRAY_OPERATOR(/, __divides)
 262 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
 263 _DEFINE_VALARRAY_OPERATOR(+, __plus)
 264 _DEFINE_VALARRAY_OPERATOR(-, __minus)
 265 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
 266 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
 267 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
 268 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
 269 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
 270
 271 #undef _DEFINE_VALARRAY_OPERATOR
 272
 273   // @} group numeric_arrays
 274
 275 _GLIBCXX_END_NAMESPACE
 276
 277 #endif /* _SLICE_ARRAY_H */