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// The template and inlines for the -*- C++ -*- gslice class. |
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// Copyright (C) 1997-2015 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. |
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// 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. |
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// 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. |
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// 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/>. |
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/** @file bits/gslice.h |
* This is an internal header file, included by other library headers. |
* Do not attempt to use it directly. @headername{valarray} |
*/ |
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// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr> |
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#ifndef _GSLICE_H |
#define _GSLICE_H 1 |
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#pragma GCC system_header |
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namespace std _GLIBCXX_VISIBILITY(default) |
{ |
_GLIBCXX_BEGIN_NAMESPACE_VERSION |
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/** |
* @addtogroup numeric_arrays |
* @{ |
*/ |
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/** |
* @brief Class defining multi-dimensional subset of an array. |
* |
* The slice class represents a multi-dimensional subset of an array, |
* specified by three parameter sets: start offset, size array, and stride |
* array. The start offset is the index of the first element of the array |
* that is part of the subset. The size and stride array describe each |
* dimension of the slice. Size is the number of elements in that |
* dimension, and stride is the distance in the array between successive |
* elements in that dimension. Each dimension's size and stride is taken |
* to begin at an array element described by the previous dimension. The |
* size array and stride array must be the same size. |
* |
* For example, if you have offset==3, stride[0]==11, size[1]==3, |
* stride[1]==3, then slice[0,0]==array[3], slice[0,1]==array[6], |
* slice[0,2]==array[9], slice[1,0]==array[14], slice[1,1]==array[17], |
* slice[1,2]==array[20]. |
*/ |
class gslice |
{ |
public: |
/// Construct an empty slice. |
gslice(); |
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/** |
* @brief Construct a slice. |
* |
* Constructs a slice with as many dimensions as the length of the @a l |
* and @a s arrays. |
* |
* @param __o Offset in array of first element. |
* @param __l Array of dimension lengths. |
* @param __s Array of dimension strides between array elements. |
*/ |
gslice(size_t __o, const valarray<size_t>& __l, |
const valarray<size_t>& __s); |
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// XXX: the IS says the copy-ctor and copy-assignment operators are |
// synthesized by the compiler but they are just unsuitable |
// for a ref-counted semantic |
/// Copy constructor. |
gslice(const gslice&); |
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/// Destructor. |
~gslice(); |
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// XXX: See the note above. |
/// Assignment operator. |
gslice& operator=(const gslice&); |
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/// Return array offset of first slice element. |
size_t start() const; |
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/// Return array of sizes of slice dimensions. |
valarray<size_t> size() const; |
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/// Return array of array strides for each dimension. |
valarray<size_t> stride() const; |
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private: |
struct _Indexer |
{ |
size_t _M_count; |
size_t _M_start; |
valarray<size_t> _M_size; |
valarray<size_t> _M_stride; |
valarray<size_t> _M_index; // Linear array of referenced indices |
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_Indexer() |
: _M_count(1), _M_start(0), _M_size(), _M_stride(), _M_index() {} |
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_Indexer(size_t, const valarray<size_t>&, |
const valarray<size_t>&); |
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void |
_M_increment_use() |
{ ++_M_count; } |
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size_t |
_M_decrement_use() |
{ return --_M_count; } |
}; |
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_Indexer* _M_index; |
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template<typename _Tp> friend class valarray; |
}; |
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inline size_t |
gslice::start() const |
{ return _M_index ? _M_index->_M_start : 0; } |
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inline valarray<size_t> |
gslice::size() const |
{ return _M_index ? _M_index->_M_size : valarray<size_t>(); } |
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inline valarray<size_t> |
gslice::stride() const |
{ return _M_index ? _M_index->_M_stride : valarray<size_t>(); } |
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// _GLIBCXX_RESOLVE_LIB_DEFECTS |
// 543. valarray slice default constructor |
inline |
gslice::gslice() |
: _M_index(new gslice::_Indexer()) {} |
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inline |
gslice::gslice(size_t __o, const valarray<size_t>& __l, |
const valarray<size_t>& __s) |
: _M_index(new gslice::_Indexer(__o, __l, __s)) {} |
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inline |
gslice::gslice(const gslice& __g) |
: _M_index(__g._M_index) |
{ if (_M_index) _M_index->_M_increment_use(); } |
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inline |
gslice::~gslice() |
{ |
if (_M_index && _M_index->_M_decrement_use() == 0) |
delete _M_index; |
} |
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inline gslice& |
gslice::operator=(const gslice& __g) |
{ |
if (__g._M_index) |
__g._M_index->_M_increment_use(); |
if (_M_index && _M_index->_M_decrement_use() == 0) |
delete _M_index; |
_M_index = __g._M_index; |
return *this; |
} |
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// @} group numeric_arrays |
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_GLIBCXX_END_NAMESPACE_VERSION |
} // namespace |
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#endif /* _GSLICE_H */ |