pqc/external/flint-2.4.3/flintxx/expression_traits.h
2014-05-24 23:16:06 +02:00

110 lines
3.3 KiB
C++

/*=============================================================================
This file is part of FLINT.
FLINT 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 of the License, or
(at your option) any later version.
FLINT 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 FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2013 Tom Bachmann
******************************************************************************/
// This file contains helpers recognising expression templates
#ifndef CXX_EXPRESSION_TRAITS_H
#define CXX_EXPRESSION_TRAITS_H
#include "mp.h"
#include "traits.h"
namespace flint {
namespace operations {
// These are the operation tags the expression class creates directly.
// unary operations
struct immediate { };
struct negate { };
struct complement { };
// binary operations
struct plus { };
struct minus { };
struct times { };
struct divided_by { };
struct modulo { };
struct shift { }; // left
struct binary_and { };
struct binary_or { };
struct binary_xor { };
} // operations
namespace traits {
template<class T, class Enable = void>
struct is_expression : mp::false_ { };
template<class T>
struct is_expression<T, typename T::IS_EXPRESSION_MARKER> : mp::true_ { };
template<class T>
struct _is_immediate_expr
: _is_convertible<
typename basetype<T>::type::operation_t,
operations::immediate
>
{ };
// Compute if T is an expression, with operation "immediate"
template<class T, class Enable = void>
struct is_immediate_expr : _is_immediate_expr<T> { };
template<class T>
struct is_immediate_expr<T,
typename mp::enable_if<mp::not_<is_expression<T> > >::type>
: mp::false_ { };
// Compute if T is an immediate expression, *or not an expression at all*
template<class T>
struct is_immediate
: mp::or_<mp::not_<is_expression<T> >, is_immediate_expr<T> > { };
// Compute if T is a non-immediate expression
template<class T>
struct is_lazy_expr
: mp::and_<is_expression<T>, mp::not_<is_immediate_expr<T> > > { };
// Compute if Expr is an expression with prescribed evaluated type "T"
template<class Expr, class T, class Enable = void>
struct is_T_expr
: mp::equal_types<typename Expr::evaluated_t, T> { };
template<class Expr, class T>
struct is_T_expr<Expr, T,
typename mp::disable_if<traits::is_expression<Expr> >::type>
: false_ { };
// Decide if an expressing yielding From can be directly evaluated into To.
// To be further specialised!
template<class To, class From, class Enable = void>
struct can_evaluate_into : mp::false_ { };
template<class T>
struct can_evaluate_into<T, T> : mp::true_ { };
// Decide if we should use temporary merging
template<class Expr>
struct use_temporary_merging : mp::true_ { };
} // traits
} // flint
#endif