// The template and inlines for the -*- C++ -*- slice_array class. // Copyright (C) 1997-2020 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. /** @file bits/slice_array.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{valarray} */ // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr> #ifndef _SLICE_ARRAY_H #define _SLICE_ARRAY_H 1 #pragma GCC system_header namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION /** * @addtogroup numeric_arrays * @{ */ /** * @brief Class defining one-dimensional subset of an array. * * The slice class represents a one-dimensional subset of an array, * specified by three parameters: start offset, size, and stride. The * start offset is the index of the first element of the array that is part * of the subset. The size is the total number of elements in the subset. * Stride is the distance between each successive array element to include * in the subset. * * For example, with an array of size 10, and a slice with offset 1, size 3 * and stride 2, the subset consists of array elements 1, 3, and 5. */ class slice { public: /// Construct an empty slice. slice(); /** * @brief Construct a slice. * * @param __o Offset in array of first element. * @param __d Number of elements in slice. * @param __s Stride between array elements. */ slice(size_t __o, size_t __d, size_t __s); /// Return array offset of first slice element. size_t start() const; /// Return size of slice. size_t size() const; /// Return array stride of slice. size_t stride() const; #if __cpp_impl_three_way_comparison >= 201907L /// Equality comparison friend bool operator==(const slice&, const slice&) = default; #endif private: size_t _M_off; // offset size_t _M_sz; // size size_t _M_st; // stride unit }; // _GLIBCXX_RESOLVE_LIB_DEFECTS // 543. valarray slice default constructor inline slice::slice() : _M_off(0), _M_sz(0), _M_st(0) {} inline slice::slice(size_t __o, size_t __d, size_t __s) : _M_off(__o), _M_sz(__d), _M_st(__s) {} inline size_t slice::start() const { return _M_off; } inline size_t slice::size() const { return _M_sz; } inline size_t slice::stride() const { return _M_st; } /** * @brief Reference to one-dimensional subset of an array. * * A slice_array is a reference to the actual elements of an array * specified by a slice. The way to get a slice_array is to call * operator[](slice) on a valarray. The returned slice_array then permits * carrying operations out on the referenced subset of elements in the * original valarray. For example, operator+=(valarray) will add values * to the subset of elements in the underlying valarray this slice_array * refers to. * * @param Tp Element type. */ template<typename _Tp> class slice_array { public: typedef _Tp value_type; // _GLIBCXX_RESOLVE_LIB_DEFECTS // 253. valarray helper functions are almost entirely useless /// Copy constructor. Both slices refer to the same underlying array. slice_array(const slice_array&); /// Assignment operator. Assigns slice elements to corresponding /// elements of @a a. slice_array& operator=(const slice_array&); /// Assign slice elements to corresponding elements of @a v. void operator=(const valarray<_Tp>&) const; /// Multiply slice elements by corresponding elements of @a v. void operator*=(const valarray<_Tp>&) const; /// Divide slice elements by corresponding elements of @a v. void operator/=(const valarray<_Tp>&) const; /// Modulo slice elements by corresponding elements of @a v. void operator%=(const valarray<_Tp>&) const; /// Add corresponding elements of @a v to slice elements. void operator+=(const valarray<_Tp>&) const; /// Subtract corresponding elements of @a v from slice elements. void operator-=(const valarray<_Tp>&) const; /// Logical xor slice elements with corresponding elements of @a v. void operator^=(const valarray<_Tp>&) const; /// Logical and slice elements with corresponding elements of @a v. void operator&=(const valarray<_Tp>&) const; /// Logical or slice elements with corresponding elements of @a v. void operator|=(const valarray<_Tp>&) const; /// Left shift slice elements by corresponding elements of @a v. void operator<<=(const valarray<_Tp>&) const; /// Right shift slice elements by corresponding elements of @a v. void operator>>=(const valarray<_Tp>&) const; /// Assign all slice elements to @a t. void operator=(const _Tp &) const; // ~slice_array (); template<class _Dom> void operator=(const _Expr<_Dom, _Tp>&) const; template<class _Dom> void operator*=(const _Expr<_Dom, _Tp>&) const; template<class _Dom> void operator/=(const _Expr<_Dom, _Tp>&) const; template<class _Dom> void operator%=(const _Expr<_Dom, _Tp>&) const; template<class _Dom> void operator+=(const _Expr<_Dom, _Tp>&) const; template<class _Dom> void operator-=(const _Expr<_Dom, _Tp>&) const; template<class _Dom> void operator^=(const _Expr<_Dom, _Tp>&) const; template<class _Dom> void operator&=(const _Expr<_Dom, _Tp>&) const; template<class _Dom> void operator|=(const _Expr<_Dom, _Tp>&) const; template<class _Dom> void operator<<=(const _Expr<_Dom, _Tp>&) const; template<class _Dom> void operator>>=(const _Expr<_Dom, _Tp>&) const; private: friend class valarray<_Tp>; slice_array(_Array<_Tp>, const slice&); const size_t _M_sz; const size_t _M_stride; const _Array<_Tp> _M_array; #if __cplusplus < 201103L // not implemented slice_array(); #else public: slice_array() = delete; #endif }; template<typename _Tp> inline slice_array<_Tp>::slice_array(_Array<_Tp> __a, const slice& __s) : _M_sz(__s.size()), _M_stride(__s.stride()), _M_array(__a.begin() + __s.start()) {} template<typename _Tp> inline slice_array<_Tp>::slice_array(const slice_array<_Tp>& __a) : _M_sz(__a._M_sz), _M_stride(__a._M_stride), _M_array(__a._M_array) {} // template<typename _Tp> // inline slice_array<_Tp>::~slice_array () {} template<typename _Tp> inline slice_array<_Tp>& slice_array<_Tp>::operator=(const slice_array<_Tp>& __a) { std::__valarray_copy(__a._M_array, __a._M_sz, __a._M_stride, _M_array, _M_stride); return *this; } template<typename _Tp> inline void slice_array<_Tp>::operator=(const _Tp& __t) const { std::__valarray_fill(_M_array, _M_sz, _M_stride, __t); } template<typename _Tp> inline void slice_array<_Tp>::operator=(const valarray<_Tp>& __v) const { std::__valarray_copy(_Array<_Tp>(__v), _M_array, _M_sz, _M_stride); } template<typename _Tp> template<class _Dom> inline void slice_array<_Tp>::operator=(const _Expr<_Dom,_Tp>& __e) const { std::__valarray_copy(__e, _M_sz, _M_array, _M_stride); } #undef _DEFINE_VALARRAY_OPERATOR #define _DEFINE_VALARRAY_OPERATOR(_Op,_Name) \ template<typename _Tp> \ inline void \ slice_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const \ { \ _Array_augmented_##_Name(_M_array, _M_sz, _M_stride, _Array<_Tp>(__v));\ } \ \ template<typename _Tp> \ template<class _Dom> \ inline void \ slice_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\ { \ _Array_augmented_##_Name(_M_array, _M_stride, __e, _M_sz); \ } _DEFINE_VALARRAY_OPERATOR(*, __multiplies) _DEFINE_VALARRAY_OPERATOR(/, __divides) _DEFINE_VALARRAY_OPERATOR(%, __modulus) _DEFINE_VALARRAY_OPERATOR(+, __plus) _DEFINE_VALARRAY_OPERATOR(-, __minus) _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor) _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and) _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or) _DEFINE_VALARRAY_OPERATOR(<<, __shift_left) _DEFINE_VALARRAY_OPERATOR(>>, __shift_right) #undef _DEFINE_VALARRAY_OPERATOR // @} group numeric_arrays _GLIBCXX_END_NAMESPACE_VERSION } // namespace #endif /* _SLICE_ARRAY_H */