valarray_meta.h

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

// Copyright (C) 1997-1999 Cygnus Solutions
//
// 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_VALARRAY_META_H
#define _CPP_VALARRAY_META_H 1

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;

    //
    // Unary function application closure.
    //
    template<class _Dom> class _UnFunBase {
    public:
        typedef typename _Dom::value_type value_type;
        typedef value_type _Vt;
        
        _UnFunBase (const _Dom& __e, _Vt __f(_Vt))
                : _M_expr(__e), _M_func(__f) {}
        
        _Vt operator[] (size_t __i) const { return _M_func(_M_expr[__i]); }
        size_t size () const { return _M_expr.size(); }
        
    private:
        const _Dom& _M_expr;
        _Vt (*_M_func)(_Vt);
    };

    template<template<class, class> class _Meta, class _Dom>
        class _UnFunClos;
    
    template<class _Dom>
    struct _UnFunClos<_Expr,_Dom> : _UnFunBase<_Dom> {
        typedef _UnFunBase<_Dom> _Base;
        typedef typename _Base::value_type value_type;
        
        _UnFunClos (const _Dom& __e, value_type __f(value_type))
                : _Base (__e, __f) {}
    };
    
    template<typename _Tp>
    struct _UnFunClos<_ValArray,_Tp> : _UnFunBase<valarray<_Tp> > {
        typedef _UnFunBase<valarray<_Tp> > _Base;
        typedef typename _Base::value_type value_type;
        
        _UnFunClos (const valarray<_Tp>& __v, _Tp __f(_Tp))
                : _Base (__v, __f) {}
    };

    //
    // Binary function application closure.
    //
    template<template<class, class> class _Meta1,
        template<class, class> class Meta2,
        class _Dom1, class _Dom2> class _BinFunClos;
    
    template<class _Dom1, class _Dom2> class _BinFunBase {
    public:
        typedef typename _Dom1::value_type value_type;
        typedef value_type _Vt;

        _BinFunBase (const _Dom1& __e1, const _Dom2& __e2,
                      _Vt __f (_Vt, _Vt))
                : _M_expr1 (__e1), _M_expr2 (__e2), _M_func (__f) {}

        value_type operator[] (size_t __i) const
        { return _M_func (_M_expr1[__i], _M_expr2[__i]); }
        size_t size () const { return _M_expr1.size (); }

    private:
        const _Dom1& _M_expr1;
        const _Dom2& _M_expr2;
        _Vt (*_M_func)(_Vt, _Vt);
    };

    template<class _Dom> class _BinFunBase1 {
    public:
        typedef typename _Dom::value_type value_type ;
        typedef value_type _Vt;

        _BinFunBase1 (const _Vt& __c, const _Dom& __e, _Vt __f(_Vt, _Vt))
                : _M_expr1 (__c), _M_expr2 (__e), _M_func (__f) {}

        value_type operator[] (size_t __i) const
        { return _M_func (_M_expr1, _M_expr2[__i]); }
        size_t size () const { return _M_expr2.size (); }

    private:
        const _Vt& _M_expr1;
        const _Dom& _M_expr2;
        _Vt (*_M_func)(_Vt, _Vt);
    };

    template<class _Dom> class _BinFunBase2 {
    public:
        typedef typename _Dom::value_type value_type;
        typedef value_type _Vt;

        _BinFunBase2 (const _Dom& __e, const _Vt& __c, _Vt __f(_Vt, _Vt))
                : _M_expr1 (__e), _M_expr2 (__c), _M_func (__f) {}

        value_type operator[] (size_t __i) const
        { return _M_func (_M_expr1[__i], _M_expr2); }
        size_t size () const { return _M_expr1.size (); }

    private:
        const _Dom& _M_expr1;
        const _Vt& _M_expr2;
        _Vt (*_M_func)(_Vt, _Vt);
    };

    template<class _Dom1, class _Dom2>
    struct _BinFunClos<_Expr,_Expr,_Dom1,_Dom2> : _BinFunBase<_Dom1,_Dom2> {
        typedef _BinFunBase<_Dom1,_Dom2> _Base;
        typedef typename _Base::value_type value_type;
        typedef value_type _Tp;

        _BinFunClos (const _Dom1& __e1, const _Dom2& __e2,
                     _Tp __f(_Tp, _Tp))
                : _Base (__e1, __e2, __f) {}
    };

    template<typename _Tp>
    struct _BinFunClos<_ValArray,_ValArray,_Tp,_Tp>
        : _BinFunBase<valarray<_Tp>, valarray<_Tp> > {
        typedef _BinFunBase<valarray<_Tp>, valarray<_Tp> > _Base;
        typedef _Tp value_type;

        _BinFunClos (const valarray<_Tp>& __v, const valarray<_Tp>& __w,
                     _Tp __f(_Tp, _Tp))
                : _Base (__v, __w, __f) {}
    };
    
    template<class _Dom>
    struct _BinFunClos<_Expr,_ValArray,_Dom,typename _Dom::value_type>
        : _BinFunBase<_Dom,valarray<typename _Dom::value_type> > {
        typedef typename _Dom::value_type _Tp;
        typedef _BinFunBase<_Dom,valarray<_Tp> > _Base;
        typedef _Tp value_type;

        _BinFunClos (const _Dom& __e, const valarray<_Tp>& __v,
                     _Tp __f(_Tp, _Tp))
                : _Base (__e, __v, __f) {}
    };

    template<class _Dom>
    struct _BinFunClos<_ValArray,_Expr,typename _Dom::value_type,_Dom>
        : _BinFunBase<valarray<typename _Dom::value_type>,_Dom> {
        typedef typename _Dom::value_type _Tp;
        typedef _BinFunBase<_Dom,valarray<_Tp> > _Base;
        typedef _Tp value_type;

        _BinFunClos (const valarray<_Tp>& __v, const _Dom& __e,
                     _Tp __f(_Tp, _Tp))
                : _Base (__v, __e, __f) {}
    };

    template<class _Dom>
    struct _BinFunClos<_Expr,_Constant,_Dom,typename _Dom::value_type>
        : _BinFunBase2<_Dom> {
        typedef typename _Dom::value_type _Tp;
        typedef _Tp value_type;
        typedef _BinFunBase2<_Dom> _Base;

        _BinFunClos (const _Dom& __e, const _Tp& __t, _Tp __f (_Tp, _Tp))
                : _Base (__e, __t, __f) {}
    };

    template<class _Dom>
    struct _BinFunClos<_Constant,_Expr,_Dom,typename _Dom::value_type>
        : _BinFunBase1<_Dom> {
        typedef typename _Dom::value_type _Tp;
        typedef _Tp value_type;
        typedef _BinFunBase1<_Dom> _Base;

        _BinFunClos (const _Tp& __t, const _Dom& __e, _Tp __f (_Tp, _Tp))
                : _Base (__t, __e, __f) {}
    };

    template<typename _Tp>
    struct _BinFunClos<_ValArray,_Constant,_Tp,_Tp>
        : _BinFunBase2<valarray<_Tp> > {
        typedef _BinFunBase2<valarray<_Tp> > _Base;
        typedef _Tp value_type;

        _BinFunClos (const valarray<_Tp>& __v, const _Tp& __t,
                     _Tp __f(_Tp, _Tp))
                : _Base (__v, __t, __f) {}
    };

    template<typename _Tp>
    struct _BinFunClos<_Constant,_ValArray,_Tp,_Tp>
        : _BinFunBase1<valarray<_Tp> > {
        typedef _BinFunBase1<valarray<_Tp> > _Base;
        typedef _Tp value_type;

        _BinFunClos (const _Tp& __t, const valarray<_Tp>& __v,
                     _Tp __f (_Tp, _Tp))
                : _Base (__t, __v, __f) {}
    };

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

    template<typename _Dom, typename _Arg> class _FunBase {
    public:
        typedef typename _Dom::value_type value_type;

        _FunBase (const _Dom& __e, value_type __f(_Arg))
                : _M_expr (__e), _M_func (__f) {}

        value_type operator[] (size_t __i) const
        { return _M_func (_M_expr[__i]); }
        size_t size() const { return _M_expr.size ();}

    private:
        const _Dom& _M_expr;
        value_type (*_M_func)(_Arg);
    };

    template<class _Dom>
    struct _ValFunClos<_Expr,_Dom>
        : _FunBase<_Dom, typename _Dom::value_type> {
        typedef _FunBase<_Dom, typename _Dom::value_type> _Base;
        typedef typename _Base::value_type value_type;
        typedef value_type _Tp;
    
        _ValFunClos (const _Dom& __e, _Tp __f (_Tp)) : _Base (__e, __f) {}
    };

    template<typename _Tp>
    struct _ValFunClos<_ValArray,_Tp>
        : _FunBase<valarray<_Tp>, _Tp> {
        typedef _FunBase<valarray<_Tp>, _Tp> _Base;
        typedef _Tp value_type;

        _ValFunClos (const valarray<_Tp>& __v, _Tp __f(_Tp))
                : _Base (__v, __f) {}
    };

    template<class _Dom>
    struct _RefFunClos<_Expr,_Dom> :
        _FunBase<_Dom, const typename _Dom::value_type&> {
        typedef _FunBase<_Dom, const typename _Dom::value_type&> _Base;
        typedef typename _Base::value_type value_type;
        typedef value_type _Tp;

        _RefFunClos (const _Dom& __e, _Tp __f (const _Tp&))
                : _Base (__e, __f) {}
    };

    template<typename _Tp>
    struct _RefFunClos<_ValArray,_Tp>
        : _FunBase<valarray<_Tp>, const _Tp&> {
        typedef _FunBase<valarray<_Tp>, const _Tp&> _Base;
        typedef _Tp value_type;
        
        _RefFunClos (const valarray<_Tp>& __v, _Tp __f(const _Tp&))
                : _Base (__e, __f) {}
    };
    
    //
    // Unary expression closure.
    //

    template<template<class> class _Oper, typename _Arg>
    class _UnBase {
    public:
        typedef _Oper<typename _Arg::value_type> _Op;
        typedef typename _Op::result_type value_type;

        _UnBase (const _Arg& __e) : _M_expr(__e) {}
        value_type operator[] (size_t) const;
        size_t size () const { return _M_expr.size (); }

    private:
        const _Arg& _M_expr;
    };

    template<template<class> class _Oper, typename _Arg>
    inline typename _UnBase<_Oper, _Arg>::value_type
    _UnBase<_Oper, _Arg>::operator[] (size_t __i) const
    { return _Op() (_M_expr[__i]); }
    
    template<template<class> class _Oper, class _Dom>
    struct _UnClos<_Oper, _Expr, _Dom> :  _UnBase<_Oper, _Dom> {
        typedef _Dom _Arg;
        typedef _UnBase<_Oper, _Dom> _Base;
        typedef typename _Base::value_type value_type;
        
        _UnClos (const _Arg& __e) : _Base(__e) {}
    };

    template<template<class> class _Oper, typename _Tp>
    struct _UnClos<_Oper, _ValArray, _Tp> : _UnBase<_Oper, valarray<_Tp> > {
        typedef valarray<_Tp> _Arg;
        typedef _UnBase<_Oper, valarray<_Tp> > _Base;
        typedef typename _Base::result_type value_type;

        _UnClos (const _Arg& __e) : _Base(__e) {}
    };


    //
    // Binary expression closure.
    //

    template<template<class> class _Oper,
        typename _FirstArg, typename _SecondArg>
    class _BinBase {
    public:
        typedef _Oper<typename _FirstArg::value_type> _Op;