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

// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2004

// 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 2, 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.

// You should have received a copy of the GNU General Public License along

// with this library; see the file COPYING.  If not, write to the Free

// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,

// USA.

// As a special exception, you may use this file as part of a free software

// library without restriction.  Specifically, if other files instantiate

// templates or use macros or inline functions from this file, or you compile

// this file and link it with other files to produce an executable, this

// file does not by itself cause the resulting executable to be covered by

// the GNU General Public License.  This exception does not however

// invalidate any other reasons why the executable file might be covered by

// the GNU General Public License.

// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>

/** @file slice_array.h

 *  This is an internal header file, included by other library headers.

 *  You should not attempt to use it directly.

 */

#ifndef _SLICE_ARRAY_H

#define _SLICE_ARRAY_H 1

#pragma GCC system_header

namespace std

{

  /**

   *  @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, size_t, size_t);

    ///  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;

  private:

    size_t _M_off;                      // offset

    size_t _M_sz;                       // size

    size_t _M_st;                       // stride unit

  };

  // The default constructor constructor is not required to initialize

  // data members with any meaningful values, so we choose to do nothing.

  inline

  slice::slice() {}

  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;

      // not implemented

      slice_array();

    };

  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

} // std::

#endif /* _SLICE_ARRAY_H */

// Local Variables:

// mode:c++

// End: