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
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 mask_array.h
00027  *  This is an internal header file, included by other library headers.
00028  *  You should not attempt to use it directly.
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 _GLIBCXX_BEGIN_NAMESPACE(std)
00039 
00040   /**
00041    * @addtogroup numeric_arrays
00042    * @{
00043    */
00044 
00045   /**
00046    *  @brief  Reference to selected subset of an array.
00047    *
00048    *  A mask_array is a reference to the actual elements of an array specified
00049    *  by a bitmask in the form of an array of bool.  The way to get a
00050    *  mask_array is to call operator[](valarray<bool>) on a valarray.  The
00051    *  returned mask_array then permits carrying operations out on the
00052    *  referenced subset of elements in the original valarray.
00053    *
00054    *  For example, if a mask_array is obtained using the array (false, true,
00055    *  false, true) as an argument, the mask array has two elements referring
00056    *  to array[1] and array[3] in the underlying array.
00057    *
00058    *  @param  Tp  Element type.
00059    */
00060   template <class _Tp>
00061     class mask_array
00062     {
00063     public:
00064       typedef _Tp value_type;
00065 
00066       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00067       // 253. valarray helper functions are almost entirely useless
00068 
00069       ///  Copy constructor.  Both slices refer to the same underlying array.
00070       mask_array (const mask_array&);
00071       
00072       ///  Assignment operator.  Assigns elements to corresponding elements
00073       ///  of @a a.
00074       mask_array& operator=(const mask_array&);
00075 
00076       void operator=(const valarray<_Tp>&) const;
00077       ///  Multiply slice elements by corresponding elements of @a v.
00078       void operator*=(const valarray<_Tp>&) const;
00079       ///  Divide slice elements by corresponding elements of @a v.
00080       void operator/=(const valarray<_Tp>&) const;
00081       ///  Modulo slice elements by corresponding elements of @a v.
00082       void operator%=(const valarray<_Tp>&) const;
00083       ///  Add corresponding elements of @a v to slice elements.
00084       void operator+=(const valarray<_Tp>&) const;
00085       ///  Subtract corresponding elements of @a v from slice elements.
00086       void operator-=(const valarray<_Tp>&) const;
00087       ///  Logical xor slice elements with corresponding elements of @a v.
00088       void operator^=(const valarray<_Tp>&) const;
00089       ///  Logical and slice elements with corresponding elements of @a v.
00090       void operator&=(const valarray<_Tp>&) const;
00091       ///  Logical or slice elements with corresponding elements of @a v.
00092       void operator|=(const valarray<_Tp>&) const;
00093       ///  Left shift slice elements by corresponding elements of @a v.
00094       void operator<<=(const valarray<_Tp>&) const;
00095       ///  Right shift slice elements by corresponding elements of @a v.
00096       void operator>>=(const valarray<_Tp>&) const;
00097       ///  Assign all slice elements to @a t.
00098       void operator=(const _Tp&) const;
00099 
00100         //        ~mask_array ();
00101 
00102       template<class _Dom>
00103         void operator=(const _Expr<_Dom,_Tp>&) const;
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 
00125     private:
00126       mask_array(_Array<_Tp>, size_t, _Array<bool>);
00127       friend class valarray<_Tp>;
00128 
00129       const size_t       _M_sz;
00130       const _Array<bool> _M_mask;
00131       const _Array<_Tp>  _M_array;
00132 
00133       // not implemented
00134       mask_array();
00135     };
00136 
00137   template<typename _Tp>
00138     inline mask_array<_Tp>::mask_array(const mask_array<_Tp>& a)
00139     : _M_sz(a._M_sz), _M_mask(a._M_mask), _M_array(a._M_array) {}
00140 
00141   template<typename _Tp>
00142     inline
00143     mask_array<_Tp>::mask_array(_Array<_Tp> __a, size_t __s, _Array<bool> __m)
00144     : _M_sz(__s), _M_mask(__m), _M_array(__a) {}
00145 
00146   template<typename _Tp>
00147     inline mask_array<_Tp>&
00148     mask_array<_Tp>::operator=(const mask_array<_Tp>& __a)
00149     {
00150       std::__valarray_copy(__a._M_array, __a._M_mask,
00151                _M_sz, _M_array, _M_mask);
00152       return *this;
00153     }
00154 
00155   template<typename _Tp>
00156     inline void
00157     mask_array<_Tp>::operator=(const _Tp& __t) const
00158     { std::__valarray_fill(_M_array, _M_sz, _M_mask, __t); }
00159 
00160   template<typename _Tp>
00161     inline void
00162     mask_array<_Tp>::operator=(const valarray<_Tp>& __v) const
00163     { std::__valarray_copy(_Array<_Tp>(__v), __v.size(), _M_array, _M_mask); }
00164 
00165   template<typename _Tp>
00166     template<class _Ex>
00167       inline void
00168       mask_array<_Tp>::operator=(const _Expr<_Ex, _Tp>& __e) const
00169       { std::__valarray_copy(__e, __e.size(), _M_array, _M_mask); }
00170 
00171 #undef _DEFINE_VALARRAY_OPERATOR
00172 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name)               \
00173   template<typename _Tp>                        \
00174     inline void                             \
00175     mask_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const    \
00176     {                                   \
00177       _Array_augmented_##_Name(_M_array, _M_mask,           \
00178                    _Array<_Tp>(__v), __v.size());       \
00179     }                                   \
00180                                     \
00181   template<typename _Tp>                                                \
00182     template<class _Dom>                                    \
00183       inline void                           \
00184       mask_array<_Tp>::operator _Op##=(const _Expr<_Dom, _Tp>& __e) const\
00185       {                                 \
00186     _Array_augmented_##_Name(_M_array, _M_mask, __e, __e.size());   \
00187       }
00188 
00189 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
00190 _DEFINE_VALARRAY_OPERATOR(/, __divides)
00191 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
00192 _DEFINE_VALARRAY_OPERATOR(+, __plus)
00193 _DEFINE_VALARRAY_OPERATOR(-, __minus)
00194 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
00195 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
00196 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
00197 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
00198 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
00199 
00200 #undef _DEFINE_VALARRAY_OPERATOR
00201 
00202   // @} group numeric_arrays
00203 
00204 _GLIBCXX_END_NAMESPACE
00205 
00206 #endif /* _MASK_ARRAY_H */

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