valarray_meta.h

俄罗斯高人Mamaich的Pocket gcc编译器（运行在PocketPC上）的全部源代码。

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

// Copyright (C) 1997, 1998, 1999, 2000, 2001 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]>

/** @file valarray_meta.h
 *  This is an internal header file, included by other library headers.
 *  You should not attempt to use it directly.
 */

#ifndef _CPP_VALARRAY_META_H
#define _CPP_VALARRAY_META_H 1

#pragma GCC system_header

namespace std
{
  //
  // Implementing a loosened valarray return value is tricky.
  // First we need to meet 26.3.1/3: we should not add more than
  // two levels of template nesting. Therefore we resort to template
  // template to "flatten" loosened return value types.
  // At some point we use partial specialization to remove one level
  // template nesting due to _Expr<>
  //
  
  // This class is NOT defined. It doesn't need to.
  template<typename _Tp1, typename _Tp2> class _Constant;

  // Implementations of unary functions applied to valarray<>s.
  // I use hard-coded object functions here instead of a generic
  // approach like pointers to function:
  //    1) correctness: some functions take references, others values.
  //       we can't deduce the correct type afterwards.
  //    2) efficiency -- object functions can be easily inlined
  //    3) be Koenig-lookup-friendly

  struct __abs
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return abs(__t); }
  };

  struct __cos
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return cos(__t); }
  };

  struct __acos
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return acos(__t); }
  };

  struct __cosh
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return cosh(__t); }
  };

  struct __sin
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return sin(__t); }
  };

  struct __asin
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return asin(__t); }
  };

  struct __sinh
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return sinh(__t); }
  };

  struct __tan
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return tan(__t); }
  };

  struct __atan
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return atan(__t); }
  };

  struct __tanh
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return tanh(__t); }
  };

  struct __exp
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return exp(__t); }
  };

  struct __log
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return log(__t); }
  };

  struct __log10
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return log10(__t); }
  };

  struct __sqrt
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return sqrt(__t); }
  };

  // In the past, we used to tailor operator applications semantics
  // to the specialization of standard function objects (i.e. plus<>, etc.)
  // That is incorrect.  Therefore we provide our own surrogates.

  struct __unary_plus
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return +__t; }
  };

  struct __negate
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return -__t; }
  };

  struct __bitwise_not
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __t) const { return ~__t; }
  };

  struct __plus
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return __x + __y; }
  };

  struct __minus
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return __x - __y; }
  };

  struct __multiplies
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return __x * __y; }
  };

  struct __divides
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return __x / __y; }
  };

  struct __modulus
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return __x % __y; }
  };

  struct __bitwise_xor
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return __x ^ __y; }
  };

  struct __bitwise_and
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return __x & __y; }
  };

  struct __bitwise_or
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return __x | __y; }
  };

  struct __shift_left
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return __x << __y; }
  };

  struct __shift_right
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return __x >> __y; }
  };

  struct __logical_and
  {
    template<typename _Tp>
      bool operator()(const _Tp& __x, const _Tp& __y) const
      { return __x && __y; }
  };

  struct __logical_or
  {
    template<typename _Tp>
      bool operator()(const _Tp& __x, const _Tp& __y) const
      { return __x || __y; }
  };

  struct __logical_not
  {
    template<typename _Tp>
      bool operator()(const _Tp& __x) const { return !__x; }
  };

  struct __equal_to
  {
    template<typename _Tp>
      bool operator()(const _Tp& __x, const _Tp& __y) const
      { return __x == __y; }
  };

  struct __not_equal_to
  {
    template<typename _Tp>
      bool operator()(const _Tp& __x, const _Tp& __y) const
      { return __x != __y; }
  };

  struct __less
  {
    template<typename _Tp>
      bool operator()(const _Tp& __x, const _Tp& __y) const
      { return __x < __y; }
  };

  struct __greater
  {
    template<typename _Tp>
      bool operator()(const _Tp& __x, const _Tp& __y) const
      { return __x > __y; }
  };

  struct __less_equal
  {
    template<typename _Tp>
      bool operator()(const _Tp& __x, const _Tp& __y) const
      { return __x <= __y; }
  };

  struct __greater_equal
  {
    template<typename _Tp>
      bool operator()(const _Tp& __x, const _Tp& __y) const
      { return __x >= __y; }
  };

  // The few binary functions we miss.
  struct __atan2
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return atan2(__x, __y); }
  };

  struct __pow
  {
    template<typename _Tp>
      _Tp operator()(const _Tp& __x, const _Tp& __y) const
      { return pow(__x, __y); }
  };


  // We need these bits in order to recover the return type of
  // some functions/operators now that we're no longer using
  // function templates.
  template<typename, typename _Tp>
    struct __fun
    {
      typedef _Tp result_type;
    };

  // several specializations for relational operators.
  template<typename _Tp>
    struct __fun<__logical_not, _Tp>
    {
      typedef bool result_type;
    };

  template<typename _Tp>
    struct __fun<__logical_and, _Tp>
    {
      typedef bool result_type;
    };

  template<typename _Tp>
    struct __fun<__logical_or, _Tp>
    {
      typedef bool result_type;
    };

  template<typename _Tp>
    struct __fun<__less, _Tp>
    {
      typedef bool result_type;
    };

  template<typename _Tp>
    struct __fun<__greater, _Tp>
    {
      typedef bool result_type;
    };

  template<typename _Tp>
    struct __fun<__less_equal, _Tp>
    {
      typedef bool result_type;
    };

  template<typename _Tp>
    struct __fun<__greater_equal, _Tp>
    {
      typedef bool result_type;
    };

  template<typename _Tp>
    struct __fun<__equal_to, _Tp>
    {
      typedef bool result_type;
    };

  template<typename _Tp>
    struct __fun<__not_equal_to, _Tp>
    {
      typedef bool result_type;
    };

    //
    // Apply function taking a value/const reference closure