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      1 // The template and inlines for the -*- C++ -*- indirect_array class.
      2 
      3 // Copyright (C) 1997-2013 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/indirect_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 (at) DPTMaths.ENS-Cachan.Fr>
     31 
     32 #ifndef _INDIRECT_ARRAY_H
     33 #define _INDIRECT_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  Reference to arbitrary subset of an array.
     48    *
     49    *  An indirect_array is a reference to the actual elements of an array
     50    *  specified by an ordered array of indices.  The way to get an
     51    *  indirect_array is to call operator[](valarray<size_t>) on a valarray.
     52    *  The returned indirect_array then permits carrying operations out on the
     53    *  referenced subset of elements in the original valarray.
     54    *
     55    *  For example, if an indirect_array is obtained using the array (4,2,0) as
     56    *  an argument, and then assigned to an array containing (1,2,3), then the
     57    *  underlying array will have array[0]==3, array[2]==2, and array[4]==1.
     58    *
     59    *  @param  Tp  Element type.
     60    */
     61   template <class _Tp>
     62     class indirect_array
     63     {
     64     public:
     65       typedef _Tp value_type;
     66 
     67       // _GLIBCXX_RESOLVE_LIB_DEFECTS
     68       // 253. valarray helper functions are almost entirely useless
     69 
     70       ///  Copy constructor.  Both slices refer to the same underlying array.
     71       indirect_array(const indirect_array&);
     72 
     73       ///  Assignment operator.  Assigns elements to corresponding elements
     74       ///  of @a a.
     75       indirect_array& operator=(const indirect_array&);
     76 
     77       ///  Assign slice elements to corresponding elements of @a v.
     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       //    ~indirect_array();
    102 
    103       template<class _Dom>
    104       void operator=(const _Expr<_Dom, _Tp>&) const;
    105       template<class _Dom>
    106       void operator*=(const _Expr<_Dom, _Tp>&) const;
    107       template<class _Dom>
    108       void operator/=(const _Expr<_Dom, _Tp>&) const;
    109       template<class _Dom>
    110       void operator%=(const _Expr<_Dom, _Tp>&) const;
    111       template<class _Dom>
    112       void operator+=(const _Expr<_Dom, _Tp>&) const;
    113       template<class _Dom>
    114       void operator-=(const _Expr<_Dom, _Tp>&) const;
    115       template<class _Dom>
    116       void operator^=(const _Expr<_Dom, _Tp>&) const;
    117       template<class _Dom>
    118       void operator&=(const _Expr<_Dom, _Tp>&) const;
    119       template<class _Dom>
    120       void operator|=(const _Expr<_Dom, _Tp>&) const;
    121       template<class _Dom>
    122       void operator<<=(const _Expr<_Dom, _Tp>&) const;
    123       template<class _Dom>
    124       void operator>>=(const _Expr<_Dom, _Tp>&) const;
    125 
    126     private:
    127       ///  Copy constructor.  Both slices refer to the same underlying array.
    128       indirect_array(_Array<_Tp>, size_t, _Array<size_t>);
    129 
    130       friend class valarray<_Tp>;
    131       friend class gslice_array<_Tp>;
    132 
    133       const size_t	 _M_sz;
    134       const _Array<size_t> _M_index;
    135       const _Array<_Tp>	 _M_array;
    136 
    137       // not implemented
    138       indirect_array();
    139     };
    140 
    141   template<typename _Tp>
    142     inline
    143     indirect_array<_Tp>::indirect_array(const indirect_array<_Tp>& __a)
    144     : _M_sz(__a._M_sz), _M_index(__a._M_index), _M_array(__a._M_array) {}
    145 
    146   template<typename _Tp>
    147     inline
    148     indirect_array<_Tp>::indirect_array(_Array<_Tp> __a, size_t __s,
    149 					_Array<size_t> __i)
    150     : _M_sz(__s), _M_index(__i), _M_array(__a) {}
    151 
    152   template<typename _Tp>
    153     inline indirect_array<_Tp>&
    154     indirect_array<_Tp>::operator=(const indirect_array<_Tp>& __a)
    155     {
    156       std::__valarray_copy(__a._M_array, _M_sz, __a._M_index, _M_array,
    157 			   _M_index);
    158       return *this;
    159     }
    160 
    161   template<typename _Tp>
    162     inline void
    163     indirect_array<_Tp>::operator=(const _Tp& __t) const
    164     { std::__valarray_fill(_M_array, _M_index, _M_sz, __t); }
    165 
    166   template<typename _Tp>
    167     inline void
    168     indirect_array<_Tp>::operator=(const valarray<_Tp>& __v) const
    169     { std::__valarray_copy(_Array<_Tp>(__v), _M_sz, _M_array, _M_index); }
    170 
    171   template<typename _Tp>
    172     template<class _Dom>
    173       inline void
    174       indirect_array<_Tp>::operator=(const _Expr<_Dom, _Tp>& __e) const
    175       { std::__valarray_copy(__e, _M_sz, _M_array, _M_index); }
    176 
    177 #undef _DEFINE_VALARRAY_OPERATOR
    178 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name)				\
    179   template<typename _Tp>						\
    180     inline void								\
    181     indirect_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const\
    182     {									\
    183       _Array_augmented_##_Name(_M_array, _M_index, _Array<_Tp>(__v), _M_sz); \
    184     }									\
    185 									\
    186   template<typename _Tp>                                                \
    187     template<class _Dom>				                \
    188       inline void							\
    189       indirect_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
    190       {									\
    191 	_Array_augmented_##_Name(_M_array, _M_index, __e, _M_sz);	\
    192       }
    193 
    194 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
    195 _DEFINE_VALARRAY_OPERATOR(/, __divides)
    196 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
    197 _DEFINE_VALARRAY_OPERATOR(+, __plus)
    198 _DEFINE_VALARRAY_OPERATOR(-, __minus)
    199 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
    200 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
    201 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
    202 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
    203 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
    204 
    205 #undef _DEFINE_VALARRAY_OPERATOR
    206 
    207   // @} group numeric_arrays
    208 
    209 _GLIBCXX_END_NAMESPACE_VERSION
    210 } // namespace
    211 
    212 #endif /* _INDIRECT_ARRAY_H */
    213