55 lines
1.2 KiB
C++
55 lines
1.2 KiB
C++
// vi:set ft=cpp: -*- Mode: C++ -*-
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#pragma once
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/*
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* (c) 2012 Alexander Warg <warg@os.inf.tu-dresden.de>,
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* economic rights: Technische Universität Dresden (Germany)
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*
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* License: see LICENSE.spdx (in this directory or the directories above)
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*/
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#include "type_traits"
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namespace cxx {
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template< typename ...T >
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struct type_list;
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template<>
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struct type_list<>
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{
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typedef false_type head;
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typedef false_type tail;
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};
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template<typename HEAD, typename ...TAIL>
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struct type_list<HEAD, TAIL...>
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{
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typedef HEAD head;
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typedef type_list<TAIL...> tail;
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};
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template<typename TYPELIST, template <typename T> class PREDICATE>
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struct find_type;
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template<template <typename T> class PREDICATE>
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struct find_type<type_list<>, PREDICATE>
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{
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typedef false_type type;
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};
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template<typename TYPELIST, template <typename T> class PREDICATE>
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struct find_type
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{
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typedef typename conditional<PREDICATE<typename TYPELIST::head>::value,
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typename TYPELIST::head,
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typename find_type<typename TYPELIST::tail, PREDICATE>::type>::type type;
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};
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template<typename TYPELIST, template <typename T> class PREDICATE>
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using find_type_t = typename find_type<TYPELIST, PREDICATE>::type;
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}
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