libstdc++
mask_array.h
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00001 // The template and inlines for the -*- C++ -*- mask_array class.
00002 
00003 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2009, 2010
00004 //  Free Software Foundation, Inc.
00005 //
00006 // This file is part of the GNU ISO C++ Library.  This library is free
00007 // software; you can redistribute it and/or modify it under the
00008 // terms of the GNU General Public License as published by the
00009 // Free Software Foundation; either version 3, or (at your option)
00010 // any later version.
00011 
00012 // This library is distributed in the hope that it will be useful,
00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015 // GNU General Public License for more details.
00016 
00017 // Under Section 7 of GPL version 3, you are granted additional
00018 // permissions described in the GCC Runtime Library Exception, version
00019 // 3.1, as published by the Free Software Foundation.
00020 
00021 // You should have received a copy of the GNU General Public License and
00022 // a copy of the GCC Runtime Library Exception along with this program;
00023 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00024 // <http://www.gnu.org/licenses/>.
00025 
00026 /** @file bits/mask_array.h
00027  *  This is an internal header file, included by other library headers.
00028  *  Do not attempt to use it directly. @headername{valarray}
00029  */
00030 
00031 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
00032 
00033 #ifndef _MASK_ARRAY_H
00034 #define _MASK_ARRAY_H 1
00035 
00036 #pragma GCC system_header
00037 
00038 namespace std _GLIBCXX_VISIBILITY(default)
00039 {
00040 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00041 
00042   /**
00043    * @addtogroup numeric_arrays
00044    * @{
00045    */
00046 
00047   /**
00048    *  @brief  Reference to selected subset of an array.
00049    *
00050    *  A mask_array is a reference to the actual elements of an array specified
00051    *  by a bitmask in the form of an array of bool.  The way to get a
00052    *  mask_array is to call operator[](valarray<bool>) on a valarray.  The
00053    *  returned mask_array then permits carrying operations out on the
00054    *  referenced subset of elements in the original valarray.
00055    *
00056    *  For example, if a mask_array is obtained using the array (false, true,
00057    *  false, true) as an argument, the mask array has two elements referring
00058    *  to array[1] and array[3] in the underlying array.
00059    *
00060    *  @param  Tp  Element type.
00061    */
00062   template <class _Tp>
00063     class mask_array
00064     {
00065     public:
00066       typedef _Tp value_type;
00067 
00068       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00069       // 253. valarray helper functions are almost entirely useless
00070 
00071       ///  Copy constructor.  Both slices refer to the same underlying array.
00072       mask_array (const mask_array&);
00073       
00074       ///  Assignment operator.  Assigns elements to corresponding elements
00075       ///  of @a a.
00076       mask_array& operator=(const mask_array&);
00077 
00078       void operator=(const valarray<_Tp>&) const;
00079       ///  Multiply slice elements by corresponding elements of @a v.
00080       void operator*=(const valarray<_Tp>&) const;
00081       ///  Divide slice elements by corresponding elements of @a v.
00082       void operator/=(const valarray<_Tp>&) const;
00083       ///  Modulo slice elements by corresponding elements of @a v.
00084       void operator%=(const valarray<_Tp>&) const;
00085       ///  Add corresponding elements of @a v to slice elements.
00086       void operator+=(const valarray<_Tp>&) const;
00087       ///  Subtract corresponding elements of @a v from slice elements.
00088       void operator-=(const valarray<_Tp>&) const;
00089       ///  Logical xor slice elements with corresponding elements of @a v.
00090       void operator^=(const valarray<_Tp>&) const;
00091       ///  Logical and slice elements with corresponding elements of @a v.
00092       void operator&=(const valarray<_Tp>&) const;
00093       ///  Logical or slice elements with corresponding elements of @a v.
00094       void operator|=(const valarray<_Tp>&) const;
00095       ///  Left shift slice elements by corresponding elements of @a v.
00096       void operator<<=(const valarray<_Tp>&) const;
00097       ///  Right shift slice elements by corresponding elements of @a v.
00098       void operator>>=(const valarray<_Tp>&) const;
00099       ///  Assign all slice elements to @a t.
00100       void operator=(const _Tp&) const;
00101 
00102         //        ~mask_array ();
00103 
00104       template<class _Dom>
00105         void operator=(const _Expr<_Dom,_Tp>&) const;
00106       template<class _Dom>
00107         void operator*=(const _Expr<_Dom,_Tp>&) const;
00108       template<class _Dom>
00109         void operator/=(const _Expr<_Dom,_Tp>&) const;
00110       template<class _Dom>
00111         void operator%=(const _Expr<_Dom,_Tp>&) const;
00112       template<class _Dom>
00113         void operator+=(const _Expr<_Dom,_Tp>&) const;
00114       template<class _Dom>
00115         void operator-=(const _Expr<_Dom,_Tp>&) const;
00116       template<class _Dom>
00117         void operator^=(const _Expr<_Dom,_Tp>&) const;
00118       template<class _Dom>
00119         void operator&=(const _Expr<_Dom,_Tp>&) const;
00120       template<class _Dom>
00121         void operator|=(const _Expr<_Dom,_Tp>&) const;
00122       template<class _Dom>
00123         void operator<<=(const _Expr<_Dom,_Tp>&) const;
00124       template<class _Dom>
00125         void operator>>=(const _Expr<_Dom,_Tp>&) const;
00126 
00127     private:
00128       mask_array(_Array<_Tp>, size_t, _Array<bool>);
00129       friend class valarray<_Tp>;
00130 
00131       const size_t       _M_sz;
00132       const _Array<bool> _M_mask;
00133       const _Array<_Tp>  _M_array;
00134 
00135       // not implemented
00136       mask_array();
00137     };
00138 
00139   template<typename _Tp>
00140     inline mask_array<_Tp>::mask_array(const mask_array<_Tp>& a)
00141     : _M_sz(a._M_sz), _M_mask(a._M_mask), _M_array(a._M_array) {}
00142 
00143   template<typename _Tp>
00144     inline
00145     mask_array<_Tp>::mask_array(_Array<_Tp> __a, size_t __s, _Array<bool> __m)
00146     : _M_sz(__s), _M_mask(__m), _M_array(__a) {}
00147 
00148   template<typename _Tp>
00149     inline mask_array<_Tp>&
00150     mask_array<_Tp>::operator=(const mask_array<_Tp>& __a)
00151     {
00152       std::__valarray_copy(__a._M_array, __a._M_mask,
00153                _M_sz, _M_array, _M_mask);
00154       return *this;
00155     }
00156 
00157   template<typename _Tp>
00158     inline void
00159     mask_array<_Tp>::operator=(const _Tp& __t) const
00160     { std::__valarray_fill(_M_array, _M_sz, _M_mask, __t); }
00161 
00162   template<typename _Tp>
00163     inline void
00164     mask_array<_Tp>::operator=(const valarray<_Tp>& __v) const
00165     { std::__valarray_copy(_Array<_Tp>(__v), __v.size(), _M_array, _M_mask); }
00166 
00167   template<typename _Tp>
00168     template<class _Ex>
00169       inline void
00170       mask_array<_Tp>::operator=(const _Expr<_Ex, _Tp>& __e) const
00171       { std::__valarray_copy(__e, __e.size(), _M_array, _M_mask); }
00172 
00173 #undef _DEFINE_VALARRAY_OPERATOR
00174 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name)               \
00175   template<typename _Tp>                        \
00176     inline void                             \
00177     mask_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const    \
00178     {                                   \
00179       _Array_augmented_##_Name(_M_array, _M_mask,           \
00180                    _Array<_Tp>(__v), __v.size());       \
00181     }                                   \
00182                                     \
00183   template<typename _Tp>                                                \
00184     template<class _Dom>                                    \
00185       inline void                           \
00186       mask_array<_Tp>::operator _Op##=(const _Expr<_Dom, _Tp>& __e) const\
00187       {                                 \
00188     _Array_augmented_##_Name(_M_array, _M_mask, __e, __e.size());   \
00189       }
00190 
00191 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
00192 _DEFINE_VALARRAY_OPERATOR(/, __divides)
00193 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
00194 _DEFINE_VALARRAY_OPERATOR(+, __plus)
00195 _DEFINE_VALARRAY_OPERATOR(-, __minus)
00196 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
00197 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
00198 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
00199 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
00200 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
00201 
00202 #undef _DEFINE_VALARRAY_OPERATOR
00203 
00204   // @} group numeric_arrays
00205 
00206 _GLIBCXX_END_NAMESPACE_VERSION
00207 } // namespace
00208 
00209 #endif /* _MASK_ARRAY_H */