valarray_array.h

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// The template and inlines for the -*- C++ -*- internal _Array helper class.

// Copyright (C) 1997-2000 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// 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 <[e-mail]>

#ifndef _CPP_BITS_ARRAY_H
#define _CPP_BITS_ARRAY_H 1

#pragma GCC system_header

#include <bits/c++config.h>
#include <bits/cpp_type_traits.h>
#include <bits/std_cstdlib.h>
#include <bits/std_cstring.h>
#include <new>

namespace std
{
  
  //
  // Helper functions on raw pointers
  //
  
  // We get memory by the old fashion way
  inline void*
  __valarray_get_memory(size_t __n)
  { return operator new(__n); }
  
  template<typename _Tp>
  inline _Tp*__restrict__
  __valarray_get_storage(size_t __n)
  {
    return static_cast<_Tp*__restrict__>
      (__valarray_get_memory(__n * sizeof(_Tp)));
  }

  // Return memory to the system
  inline void
  __valarray_release_memory(void* __p)
  { operator delete(__p); }

  // Turn a raw-memory into an array of _Tp filled with _Tp()
  // This is required in 'valarray<T> v(n);'
  template<typename _Tp, bool>
  struct _Array_default_ctor
  {
    // Please note that this isn't exception safe.  But
    // valarrays aren't required to be exception safe.
    inline static void
    _S_do_it(_Tp* __restrict__ __b, _Tp* __restrict__ __e)
    { while (__b != __e) new(__b++) _Tp(); }
  };

  template<typename _Tp>
  struct _Array_default_ctor<_Tp, true>
  {
    // For fundamental types, it suffices to say 'memset()'
    inline static void
    _S_do_it(_Tp* __restrict__ __b, _Tp* __restrict__ __e)
    { memset(__b, 0, (__e - __b)*sizeof(_Tp)); }
  };

  template<typename _Tp>
  inline void
  __valarray_default_construct(_Tp* __restrict__ __b, _Tp* __restrict__ __e)
  {
    _Array_default_ctor<_Tp, __is_fundamental<_Tp>::_M_type>::
      _S_do_it(__b, __e);
  }
    
  // Turn a raw-memory into an array of _Tp filled with __t
  // This is the required in valarray<T> v(n, t).  Also
  // used in valarray<>::resize().
  template<typename _Tp, bool>
  struct _Array_init_ctor
  {
    // Please note that this isn't exception safe.  But
    // valarrays aren't required to be exception safe.
    inline static void
    _S_do_it(_Tp* __restrict__ __b, _Tp* __restrict__ __e, const _Tp __t)
    { while (__b != __e) new(__b++) _Tp(__t); }
  };

  template<typename _Tp>
  struct _Array_init_ctor<_Tp, true>
  {
    inline static void
    _S_do_it(_Tp* __restrict__ __b, _Tp* __restrict__ __e,  const _Tp __t)
    { while (__b != __e) *__b++ = __t; }
  };

  template<typename _Tp>
  inline void
  __valarray_fill_construct(_Tp* __restrict__ __b, _Tp* __restrict__ __e,
                            const _Tp __t)
  {
    _Array_init_ctor<_Tp, __is_fundamental<_Tp>::_M_type>::
      _S_do_it(__b, __e, __t);
  }

  //
  // copy-construct raw array [__o, *) from plain array [__b, __e)
  // We can't just say 'memcpy()'
  //
  template<typename _Tp, bool>
  struct _Array_copy_ctor
  {
    // Please note that this isn't exception safe.  But
    // valarrays aren't required to be exception safe.
    inline static void
    _S_do_it(const _Tp* __restrict__ __b, const _Tp* __restrict__ __e,
             _Tp* __restrict__ __o)
    { while (__b != __e) new(__o++) _Tp(*__b++); }
  };

  template<typename _Tp>
  struct _Array_copy_ctor<_Tp, true>
  {
    inline static void
    _S_do_it(const _Tp* __restrict__ __b, const _Tp* __restrict__ __e,
             _Tp* __restrict__ __o)
    { memcpy(__o, __b, (__e - __b)*sizeof(_Tp)); }
  };

  template<typename _Tp>
  inline void
  __valarray_copy_construct(const _Tp* __restrict__ __b,
                            const _Tp* __restrict__ __e,
                            _Tp* __restrict__ __o)
  {
    _Array_copy_ctor<_Tp, __is_fundamental<_Tp>::_M_type>::
      _S_do_it(__b, __e, __o);
  }

  // copy-construct raw array [__o, *) from strided array __a[<__n : __s>]
  template<typename _Tp>
  inline void
  __valarray_copy_construct (const _Tp* __restrict__ __a, size_t __n,
                             size_t __s, _Tp* __restrict__ __o)
  {
    if (__is_fundamental<_Tp>::_M_type)
      while (__n--) { *__o++ = *__a; __a += __s; }
    else
      while (__n--) { new(__o++) _Tp(*__a);  __a += __s; }
  }

  // copy-construct raw array [__o, *) from indexed array __a[__i[<__n>]]
  template<typename _Tp>
  inline void
  __valarray_copy_construct (const _Tp* __restrict__ __a,
                             const size_t* __restrict__ __i,
                             _Tp* __restrict__ __o, size_t __n)
  {
    if (__is_fundamental<_Tp>::_M_type)
      while (__n--) *__o++ = __a[*__i++];
    else
      while (__n--) new (__o++) _Tp(__a[*__i++]);
  }

  // Do the necessary cleanup when we're done with arrays.
  template<typename _Tp>
  inline void
  __valarray_destroy_elements(_Tp* __restrict__ __b, _Tp* __restrict__ __e)
  {
    if (!__is_fundamental<_Tp>::_M_type)
      while (__b != __e) { __b->~_Tp(); ++__b; }
  }
    
  // fill plain array __a[<__n>] with __t
  template<typename _Tp>
  void
  __valarray_fill (_Tp* __restrict__ __a, size_t __n, const _Tp& __t)
  { while (__n--) *__a++ = __t; }
  
  // fill strided array __a[<__n-1 : __s>] with __t
  template<typename _Tp>
  inline void
  __valarray_fill (_Tp* __restrict__ __a, size_t __n,
                   size_t __s, const _Tp& __t)
  { for (size_t __i=0; __i<__n; ++__i, __a+=__s) *__a = __t; }

  // fill indir   ect array __a[__i[<__n>]] with __i
  template<typename _Tp>
  inline void
  __valarray_fill(_Tp* __restrict__ __a, const size_t* __restrict__ __i,
                  size_t __n, const _Tp& __t)
  { for (size_t __j=0; __j<__n; ++__j, ++__i) __a[*__i] = __t; }
    
  // copy plain array __a[<__n>] in __b[<__n>]
  // For non-fundamental types, it is wrong to say 'memcpy()'
  template<typename _Tp, bool>
  struct _Array_copier
  {
    inline static void
    _S_do_it(const _Tp* __restrict__ __a, size_t __n, _Tp* __restrict__ __b)
    { while (__n--) *__b++ = *__a++; }      
  };

  template<typename _Tp>
  struct _Array_copier<_Tp, true>
  {
    inline static void
    _S_do_it(const _Tp* __restrict__ __a, size_t __n, _Tp* __restrict__ __b)
    { memcpy (__b, __a, __n * sizeof (_Tp)); }
  };

  template<typename _Tp>
  inline void
  __valarray_copy (const _Tp* __restrict__ __a, size_t __n,
                   _Tp* __restrict__ __b)
  {
    _Array_copier<_Tp, __is_fundamental<_Tp>::_M_type>::
      _S_do_it(__a, __n, __b);
  }

  // copy strided array __a[<__n : __s>] in plain __b[<__n>]
  template<typename _Tp>
  inline void
  __valarray_copy (const _Tp* __restrict__ __a, size_t __n, size_t __s,
                   _Tp* __restrict__ __b)
  { for (size_t __i=0; __i<__n; ++__i, ++__b, __a += __s) *__b = *__a; }

  // copy plain __a[<__n>] in strided __b[<__n : __s>]
  template<typename _Tp>
  inline void
  __valarray_copy (const _Tp* __restrict__ __a, _Tp* __restrict__ __b,
                   size_t __n, size_t __s)
  { for (size_t __i=0; __i<__n; ++__i, ++__a, __b+=__s) *__b = *__a; }
  
  // copy indexed __a[__i[<__n>]] in plain __b[<__n>]
  template<typename _Tp>
  inline void
  __valarray_copy (const _Tp* __restrict__ __a,
                   const size_t* __restrict__ __i,
                   _Tp* __restrict__ __b, size_t __n)
  { for (size_t __j=0; __j<__n; ++__j, ++__b, ++__i) *__b = __a[*__i]; }

  // copy plain __a[<__n>] in indexed __b[__i[<__n>]]
  template<typename _Tp>
  inline void
  __valarray_copy (const _Tp* __restrict__ __a, size_t __n,
                   _Tp* __restrict__ __b, const size_t* __restrict__ __i)
  { for (size_t __j=0; __j<__n; ++__j, ++__a, ++__i) __b[*__i] = *__a; }


  //
  // Compute the sum of elements in range [__f, __l)
  // This is a naive algorithm.  It suffers from cancelling.
  // In the future try to specialize
  // for _Tp = float, double, long double using a more accurate
  // algorithm.
  //
  template<typename _Tp>
  inline _Tp
  __valarray_sum(const _Tp* __restrict__ __f, const _Tp* __restrict__ __l)
  {
    _Tp __r = _Tp();
    while (__f != __l) __r += *__f++;
    return __r;
  }

  // Compute the product of all elements in range [__f, __l)
  template<typename _Tp>