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
   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 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
  32
  33 /** @file slice_array.h
  34  *  This is an internal header file, included by other library headers.
  35  *  You should not attempt to use it directly.
  36  */
  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    *  @brief  Class defining one-dimensional subset of an array.
  47    *
  48    *  The slice class represents a one-dimensional subset of an array,
  49    *  specified by three parameters: start offset, size, and stride.  The
  50    *  start offset is the index of the first element of the array that is part
  51    *  of the subset.  The size is the total number of elements in the subset.
  52    *  Stride is the distance between each successive array element to include
  53    *  in the subset.
  54    *
  55    *  For example, with an array of size 10, and a slice with offset 1, size 3
  56    *  and stride 2, the subset consists of array elements 1, 3, and 5.
  57    */
  58   class slice
  59   {
  60   public:
  61     ///  Construct an empty slice.
  62     slice();
  63
  64     /**
  65      *  @brief  Construct a slice.
  66      *
  67      *  @param  o  Offset in array of first element.
  68      *  @param  d  Number of elements in slice.
  69      *  @param  s  Stride between array elements.
  70      */
  71     slice(size_t, size_t, size_t);
  72
  73     ///  Return array offset of first slice element.
  74     size_t start() const;
  75     ///  Return size of slice.
  76     size_t size() const;
  77     ///  Return array stride of slice.
  78     size_t stride() const;
  79
  80   private:
  81     size_t _M_off;                      // offset
  82     size_t _M_sz;                       // size
  83     size_t _M_st;                       // stride unit
  84   };
  85
  86   // The default constructor constructor is not required to initialize
  87   // data members with any meaningful values, so we choose to do nothing.
  88   inline
  89   slice::slice() {}
  90
  91   inline
  92   slice::slice(size_t __o, size_t __d, size_t __s)
  93   : _M_off(__o), _M_sz(__d), _M_st(__s) {}
  94
  95   inline size_t
  96   slice::start() const
  97   { return _M_off; }
  98
  99   inline size_t
 100   slice::size() const
 101   { return _M_sz; }
 102
 103   inline size_t
 104   slice::stride() const
 105   { return _M_st; }
 106
 107   /**
 108    *  @brief  Reference to one-dimensional subset of an array.
 109    *
 110    *  A slice_array is a reference to the actual elements of an array
 111    *  specified by a slice.  The way to get a slice_array is to call
 112    *  operator[](slice) on a valarray.  The returned slice_array then permits
 113    *  carrying operations out on the referenced subset of elements in the
 114    *  original valarray.  For example, operator+=(valarray) will add values
 115    *  to the subset of elements in the underlying valarray this slice_array
 116    *  refers to.
 117    *
 118    *  @param  Tp  Element type.
 119    */
 120   template<typename _Tp>
 121     class slice_array
 122     {
 123     public:
 124       typedef _Tp value_type;
 125
 126       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 127       // 253. valarray helper functions are almost entirely useless
 128
 129       ///  Copy constructor.  Both slices refer to the same underlying array.
 130       slice_array(const slice_array&);
 131
 132       ///  Assignment operator.  Assigns slice elements to corresponding
 133       ///  elements of @a a.
 134       slice_array& operator=(const slice_array&);
 135
 136       ///  Assign slice elements to corresponding elements of @a v.
 137       void operator=(const valarray<_Tp>&) const;
 138       ///  Multiply slice elements by corresponding elements of @a v.
 139       void operator*=(const valarray<_Tp>&) const;
 140       ///  Divide slice elements by corresponding elements of @a v.
 141       void operator/=(const valarray<_Tp>&) const;
 142       ///  Modulo slice elements by corresponding elements of @a v.
 143       void operator%=(const valarray<_Tp>&) const;
 144       ///  Add corresponding elements of @a v to slice elements.
 145       void operator+=(const valarray<_Tp>&) const;
 146       ///  Subtract corresponding elements of @a v from slice elements.
 147       void operator-=(const valarray<_Tp>&) const;
 148       ///  Logical xor slice elements with corresponding elements of @a v.
 149       void operator^=(const valarray<_Tp>&) const;
 150       ///  Logical and slice elements with corresponding elements of @a v.
 151       void operator&=(const valarray<_Tp>&) const;
 152       ///  Logical or slice elements with corresponding elements of @a v.
 153       void operator|=(const valarray<_Tp>&) const;
 154       ///  Left shift slice elements by corresponding elements of @a v.
 155       void operator<<=(const valarray<_Tp>&) const;
 156       ///  Right shift slice elements by corresponding elements of @a v.
 157       void operator>>=(const valarray<_Tp>&) const;
 158       ///  Assign all slice elements to @a t.
 159       void operator=(const _Tp &) const;
 160       //        ~slice_array ();
 161
 162       template<class _Dom>
 163         void operator=(const _Expr<_Dom, _Tp>&) const;
 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
 185     private:
 186       friend class valarray<_Tp>;
 187       slice_array(_Array<_Tp>, const slice&);
 188
 189       const size_t      _M_sz;
 190       const size_t      _M_stride;
 191       const _Array<_Tp> _M_array;
 192
 193       // not implemented
 194       slice_array();
 195     };
 196
 197   template<typename _Tp>
 198     inline
 199     slice_array<_Tp>::slice_array(_Array<_Tp> __a, const slice& __s)
 200     : _M_sz(__s.size()), _M_stride(__s.stride()),
 201       _M_array(__a.begin() + __s.start()) {}
 202
 203   template<typename _Tp>
 204     inline
 205     slice_array<_Tp>::slice_array(const slice_array<_Tp>& a)
 206     : _M_sz(a._M_sz), _M_stride(a._M_stride), _M_array(a._M_array) {}
 207
 208   //    template<typename _Tp>
 209   //    inline slice_array<_Tp>::~slice_array () {}
 210
 211   template<typename _Tp>
 212     inline slice_array<_Tp>&
 213     slice_array<_Tp>::operator=(const slice_array<_Tp>& __a)
 214     {
 215       std::__valarray_copy(__a._M_array, __a._M_sz, __a._M_stride,
 216                            _M_array, _M_stride);
 217       return *this;
 218     }
 219
 220   template<typename _Tp>
 221     inline void
 222     slice_array<_Tp>::operator=(const _Tp& __t) const
 223     { std::__valarray_fill(_M_array, _M_sz, _M_stride, __t); }
 224
 225   template<typename _Tp>
 226     inline void
 227     slice_array<_Tp>::operator=(const valarray<_Tp>& __v) const
 228     { std::__valarray_copy(_Array<_Tp>(__v), _M_array, _M_sz, _M_stride); }
 229
 230   template<typename _Tp>
 231   template<class _Dom>
 232     inline void
 233     slice_array<_Tp>::operator=(const _Expr<_Dom,_Tp>& __e) const
 234     { std::__valarray_copy(__e, _M_sz, _M_array, _M_stride); }
 235
 236 #undef _DEFINE_VALARRAY_OPERATOR
 237 #define _DEFINE_VALARRAY_OPERATOR(_Op,_Name)                            \
 238   template<typename _Tp>                                                \
 239     inline void                                                         \
 240     slice_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const   \
 241     {                                                                   \
 242       _Array_augmented_##_Name(_M_array, _M_sz, _M_stride, _Array<_Tp>(__v));\
 243     }                                                                   \
 244                                                                         \
 245   template<typename _Tp>                                                \
 246     template<class _Dom>                                                \
 247       inline void                                                       \
 248       slice_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
 249       {                                                                 \
 250           _Array_augmented_##_Name(_M_array, _M_stride, __e, _M_sz);    \
 251       }
 252
 253
 254 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
 255 _DEFINE_VALARRAY_OPERATOR(/, __divides)
 256 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
 257 _DEFINE_VALARRAY_OPERATOR(+, __plus)
 258 _DEFINE_VALARRAY_OPERATOR(-, __minus)
 259 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
 260 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
 261 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
 262 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
 263 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
 264
 265 #undef _DEFINE_VALARRAY_OPERATOR
 266
 267 _GLIBCXX_END_NAMESPACE
 268
 269 #endif /* _SLICE_ARRAY_H */