indirect_array.h
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// The template and inlines for the -*- C++ -*- indirect_array class.
// Copyright (C) 1997-2013 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
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/** @file bits/indirect_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 _INDIRECT_ARRAY_H
#define _INDIRECT_ARRAY_H 1
#pragma GCC system_header
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @addtogroup numeric_arrays
* @{
*/
/**
* @brief Reference to arbitrary subset of an array.
*
* An indirect_array is a reference to the actual elements of an array
* specified by an ordered array of indices. The way to get an
* indirect_array is to call operator[](valarray<size_t>) on a valarray.
* The returned indirect_array then permits carrying operations out on the
* referenced subset of elements in the original valarray.
*
* For example, if an indirect_array is obtained using the array (4,2,0) as
* an argument, and then assigned to an array containing (1,2,3), then the
* underlying array will have array[0]==3, array[2]==2, and array[4]==1.
*
* @param Tp Element type.
*/
template <class _Tp>
class indirect_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.
indirect_array(const indirect_array&);
/// Assignment operator. Assigns elements to corresponding elements
/// of @a a.
indirect_array& operator=(const indirect_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;
// ~indirect_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:
/// Copy constructor. Both slices refer to the same underlying array.
indirect_array(_Array<_Tp>, size_t, _Array<size_t>);
friend class valarray<_Tp>;
friend class gslice_array<_Tp>;
const size_t _M_sz;
const _Array<size_t> _M_index;
const _Array<_Tp> _M_array;
// not implemented
indirect_array();
};
template<typename _Tp>
inline
indirect_array<_Tp>::indirect_array(const indirect_array<_Tp>& __a)
: _M_sz(__a._M_sz), _M_index(__a._M_index), _M_array(__a._M_array) {}
template<typename _Tp>
inline
indirect_array<_Tp>::indirect_array(_Array<_Tp> __a, size_t __s,
_Array<size_t> __i)
: _M_sz(__s), _M_index(__i), _M_array(__a) {}
template<typename _Tp>
inline indirect_array<_Tp>&
indirect_array<_Tp>::operator=(const indirect_array<_Tp>& __a)
{
std::__valarray_copy(__a._M_array, _M_sz, __a._M_index, _M_array,
_M_index);
return *this;
}
template<typename _Tp>
inline void
indirect_array<_Tp>::operator=(const _Tp& __t) const
{ std::__valarray_fill(_M_array, _M_index, _M_sz, __t); }
template<typename _Tp>
inline void
indirect_array<_Tp>::operator=(const valarray<_Tp>& __v) const
{ std::__valarray_copy(_Array<_Tp>(__v), _M_sz, _M_array, _M_index); }
template<typename _Tp>
template<class _Dom>
inline void
indirect_array<_Tp>::operator=(const _Expr<_Dom, _Tp>& __e) const
{ std::__valarray_copy(__e, _M_sz, _M_array, _M_index); }
#undef _DEFINE_VALARRAY_OPERATOR
#define _DEFINE_VALARRAY_OPERATOR(_Op, _Name) \
template<typename _Tp> \
inline void \
indirect_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const\
{ \
_Array_augmented_##_Name(_M_array, _M_index, _Array<_Tp>(__v), _M_sz); \
} \
\
template<typename _Tp> \
template<class _Dom> \
inline void \
indirect_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
{ \
_Array_augmented_##_Name(_M_array, _M_index, __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 /* _INDIRECT_ARRAY_H */