libstdc++-v3/include/bits/slice_array.h - gcc - Git at Google

 // The template and inlines for the -*- C++ -*- slice_array class.

 // Copyright (C) 1997-2025 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

 #ifdef _GLIBCXX_SYSHDR
 #pragma GCC system_header
 #endif

 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); }

   /// @cond undocumented
 #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
   /// @endcond

   /// @} group numeric_arrays

 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace

 #endif /* _SLICE_ARRAY_H */
	// The template and inlines for the -- C++ -- slice_array class.

	// Copyright (C) 1997-2025 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

	#ifdef _GLIBCXX_SYSHDR
	#pragma GCC system_header
	#endif

	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); }

	/// @cond undocumented
	#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
	/// @endcond

	/// @} group numeric_arrays

	_GLIBCXX_END_NAMESPACE_VERSION
	} // namespace

	#endif /* _SLICE_ARRAY_H */