deba@1993: /* -*- C++ -*-
deba@1993:  *
deba@1993:  * This file is a part of LEMON, a generic C++ optimization library
deba@1993:  *
deba@1993:  * Copyright (C) 2003-2006
deba@1993:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
deba@1993:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
deba@1993:  *
deba@1993:  * Permission to use, modify and distribute this software is granted
deba@1993:  * provided that this copyright notice appears in all copies. For
deba@1993:  * precise terms see the accompanying LICENSE file.
deba@1993:  *
deba@1993:  * This software is provided "AS IS" with no warranty of any kind,
deba@1993:  * express or implied, and with no claim as to its suitability for any
deba@1993:  * purpose.
deba@1993:  *
deba@1993:  */
deba@1993: 
deba@1993: // This file contains a modified version of the enable_if library from BOOST.
deba@1993: // See the appropriate copyright notice below.
deba@1993: 
deba@1993: // Boost enable_if library
deba@1993: 
deba@1993: // Copyright 2003 © The Trustees of Indiana University.
deba@1993: 
deba@1993: // Use, modification, and distribution is subject to the Boost Software
deba@1993: // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
deba@1993: // http://www.boost.org/LICENSE_1_0.txt)
deba@1993: 
deba@1993: //    Authors: Jaakko Järvi (jajarvi at osl.iu.edu)
deba@1993: //             Jeremiah Willcock (jewillco at osl.iu.edu)
deba@1993: //             Andrew Lumsdaine (lums at osl.iu.edu)
deba@1993: 
deba@1993: 
deba@1993: #ifndef LEMON_BITS_UTILITY_H
deba@1993: #define LEMON_BITS_UTILITY_H
deba@1993: 
deba@2077: #include <lemon/error.h>
deba@2077: 
deba@1993: ///\file
deba@1993: ///\brief Miscellaneous basic utilities
deba@1993: ///
deba@1993: ///\todo Please rethink the organisation of the basic files like this.
deba@1993: ///E.g. this file might be merged with invalid.h.
deba@1993: 
deba@1993: 
deba@1993: namespace lemon
deba@1993: {
deba@1993: 
deba@1993:   /// Basic type for defining "tags". A "YES" condition for \c enable_if.
deba@1993: 
deba@1993:   /// Basic type for defining "tags". A "YES" condition for \c enable_if.
deba@1993:   ///
deba@1993:   ///\sa False
deba@1993:   ///
deba@1993:   /// \todo This should go to a separate "basic_types.h" (or something)
deba@1993:   /// file.
deba@1993:   struct True {
deba@1993:     ///\e
deba@1993:     static const bool value = true;
deba@1993:   };
deba@1993: 
deba@1993:   /// Basic type for defining "tags". A "NO" condition for \c enable_if.
deba@1993: 
deba@1993:   /// Basic type for defining "tags". A "NO" condition for \c enable_if.
deba@1993:   ///
deba@1993:   ///\sa True
deba@1993:   struct False {
deba@1993:     ///\e
deba@1993:     static const bool value = false;
deba@1993:   };
deba@1993: 
deba@1993: 
deba@1993:   class InvalidType {
deba@1993:   private:
deba@1993:     InvalidType();
deba@1993:   };
deba@2077: 
deba@2077:   template <bool left, bool right>
deba@2077:   struct CTOr {
deba@2077:     static const bool value = true;
deba@2077:   };
deba@2077: 
deba@2077:   template <>
deba@2077:   struct CTOr<false, false> {
deba@2077:     static const bool value = false;
deba@2077:   };
deba@2077: 
deba@2077:   template <bool left, bool right>
deba@2077:   struct CTAnd {
deba@2077:     static const bool value = false;
deba@2077:   };
deba@2077: 
deba@2077:   template <>
deba@2077:   struct CTAnd<true, true> {
deba@2077:     static const bool value = true;
deba@2077:   };
deba@2077: 
deba@2077:   template <int left, int right>
deba@2077:   struct CTEqual {
deba@2077:     static const bool value = false;
deba@2077:   };
deba@2077: 
deba@2077:   template <int val>
deba@2077:   struct CTEqual<val, val> {
deba@2077:     static const bool value = true;
deba@2077:   };
deba@2077: 
deba@2077: 
deba@2077:   template <int left, int right>
deba@2077:   struct CTLess {
deba@2078:     static const bool value = left < right;
deba@2077:   };
deba@2077: 
deba@2077:   template <int left>
deba@2077:   struct CTLess<left, 0> {
deba@2077:     static const bool value = false;
deba@2077:   };
deba@2077: 
deba@2077:   template <int right>
deba@2077:   struct CTLess<0, right> {
deba@2077:     static const bool value = true;
deba@2077:   };
deba@2077: 
deba@2077:   template <>
deba@2077:   struct CTLess<0, 0> {
deba@2077:     static const bool value = false;
deba@2077:   };
deba@2077: 
deba@2077:   template <>
deba@2077:   struct CTLess<1, 1> {
deba@2077:     static const bool value = false;
deba@2077:   };
deba@2077: 
deba@2077:   template <bool less, int left, int right>
deba@2077:   struct CTMaxImpl {
deba@2077:     static const int value = left;    
deba@2077:   };
deba@2077: 
deba@2077:   template <int left, int right>
deba@2077:   struct CTMaxImpl<true, left, right> {
deba@2077:     static const int value = right;
deba@2077:   };
deba@1993:   
deba@2077:   template <int left, int right>
deba@2077:   struct CTMax {
deba@2077:     static const int value = 
deba@2077:     CTMaxImpl<CTLess<left, right>::value, left, right>::value;
deba@2077:   };
deba@2077: 
deba@2077: 
deba@2077:   /// \brief Simple Variant type with two type
deba@2077:   ///
deba@2077:   /// Simple Variant type with two type
deba@2077:   template <typename _First, typename _Second>
deba@2077:   class BiVariant {
deba@2077:   public:
deba@2077: 
deba@2077:     typedef _First First;
deba@2077:     typedef _Second Second;
deba@2077: 
deba@2077:     struct WrongStateError : public lemon::LogicError {
deba@2077:     public:
deba@2077:       virtual const char* exceptionName() const {
deba@2077:         return "lemon::BiVariant::WrongStateError";
deba@2077:       }
deba@2077:     };
deba@2077: 
deba@2077:     BiVariant() {
deba@2077:       flag = true;
deba@2077:       new(reinterpret_cast<First*>(data)) First();
deba@2077:     }
deba@2077: 
deba@2077:     BiVariant(const First& first) {
deba@2077:       flag = true;
deba@2077:       new(reinterpret_cast<First*>(data)) First(first);
deba@2077:     }
deba@2077: 
deba@2077:     BiVariant(const Second& second) {
deba@2077:       flag = false;
deba@2077:       new(reinterpret_cast<Second*>(data)) Second(second);
deba@2077:     }
deba@2077: 
deba@2077:     BiVariant(const BiVariant& bivariant) {
deba@2077:       flag = bivariant.flag;
deba@2077:       if (flag) {
deba@2077:         new(reinterpret_cast<First*>(data)) First(bivariant.first());      
deba@2077:       } else {
deba@2077:         new(reinterpret_cast<Second*>(data)) Second(bivariant.second());      
deba@2077:       }
deba@2077:     }
deba@2077: 
deba@2077:     ~BiVariant() {
deba@2077:       destroy();
deba@2077:     }
deba@2077: 
deba@2077:     BiVariant& setFirst() {
deba@2077:       destroy();
deba@2077:       flag = true;
deba@2077:       new(reinterpret_cast<First*>(data)) First();   
deba@2077:       return *this;
deba@2077:     }
deba@2077: 
deba@2077:     BiVariant& setFirst(const First& first) {
deba@2077:       destroy();
deba@2077:       flag = true;
deba@2077:       new(reinterpret_cast<First*>(data)) First(first);   
deba@2077:       return *this;
deba@2077:     }
deba@2077: 
deba@2077:     BiVariant& setSecond() {
deba@2077:       destroy();
deba@2077:       flag = false;
deba@2077:       new(reinterpret_cast<Second*>(data)) Second();   
deba@2077:       return *this;
deba@2077:     }
deba@2077: 
deba@2077:     BiVariant& setSecond(const Second& second) {
deba@2077:       destroy();
deba@2077:       flag = false;
deba@2077:       new(reinterpret_cast<Second*>(data)) Second(second);   
deba@2077:       return *this;
deba@2077:     }
deba@2077: 
deba@2077:     BiVariant& operator=(const First& first) {
deba@2077:       return setFirst(first);
deba@2077:     }
deba@2077: 
deba@2077:     BiVariant& operator=(const Second& second) {
deba@2077:       return setSecond(second);
deba@2077:     }
deba@2077: 
deba@2077: 
deba@2077:     BiVariant& operator=(const BiVariant& bivariant) {
deba@2077:       if (this == &bivariant) return *this;
deba@2077:       destroy();
deba@2077:       flag = bivariant.flag;
deba@2077:       if (flag) {
deba@2077:         new(reinterpret_cast<First*>(data)) First(bivariant.first());      
deba@2077:       } else {
deba@2077:         new(reinterpret_cast<Second*>(data)) Second(bivariant.second());      
deba@2077:       }
deba@2077:       return *this;
deba@2077:     }
deba@2077: 
deba@2077:     First& first() {
deba@2077:       LEMON_ASSERT(flag, WrongStateError());
deba@2077:       return *reinterpret_cast<First*>(data); 
deba@2077:     }
deba@2077: 
deba@2077:     const First& first() const { 
deba@2077:       LEMON_ASSERT(flag, WrongStateError());
deba@2077:       return *reinterpret_cast<const First*>(data); 
deba@2077:     }
deba@2077: 
deba@2077:     operator First&() { return first(); }
deba@2077:     operator const First&() const { return first(); }
deba@2077: 
deba@2077:     Second& second() { 
deba@2077:       LEMON_ASSERT(!flag, WrongStateError());
deba@2077:       return *reinterpret_cast<Second*>(data); 
deba@2077:     }
deba@2077: 
deba@2077:     const Second& second() const { 
deba@2077:       LEMON_ASSERT(!flag, WrongStateError());
deba@2077:       return *reinterpret_cast<const Second*>(data); 
deba@2077:     }
deba@2077: 
deba@2077:     operator Second&() { return second(); }
deba@2077:     operator const Second&() const { return second(); }
deba@2077: 
deba@2077:     bool firstState() const { return flag; }
deba@2077:     bool secondState() const { return !flag; }
deba@2077: 
deba@2077:   private:
deba@2077: 
deba@2077:     void destroy() {
deba@2077:       if (flag) {
deba@2077:         reinterpret_cast<First*>(data)->~First();
deba@2077:       } else {
deba@2077:         reinterpret_cast<Second*>(data)->~Second();
deba@2077:       }
deba@2077:     }
deba@2077:     
deba@2077:     char data[CTMax<sizeof(First), sizeof(Second)>::value];
deba@2077:     bool flag;
deba@2077:   };
deba@1993: 
deba@1993:   template <typename T>
deba@1993:   struct Wrap {
deba@1993:     const T &value;
deba@1993:     Wrap(const T &t) : value(t) {}
deba@1993:   };
deba@1993: 
deba@1993:   /**************** dummy class to avoid ambiguity ****************/
deba@1993: 
deba@1993:   template<int T> struct dummy { dummy(int) {} };
deba@1993: 
deba@1993:   /**************** enable_if from BOOST ****************/
deba@1993:  
deba@1993:   template <bool B, class T = void>
deba@1993:   struct enable_if_c {
deba@1993:     typedef T type;
deba@1993:   };
deba@1993: 
deba@1993:   template <class T>
deba@1993:   struct enable_if_c<false, T> {};
deba@1993: 
deba@1993:   template <class Cond, class T = void> 
deba@1993:   struct enable_if : public enable_if_c<Cond::value, T> {};
deba@1993: 
deba@1993:   template <bool B, class T>
deba@1993:   struct lazy_enable_if_c {
deba@1993:     typedef typename T::type type;
deba@1993:   };
deba@1993: 
deba@1993:   template <class T>
deba@1993:   struct lazy_enable_if_c<false, T> {};
deba@1993: 
deba@1993:   template <class Cond, class T> 
deba@1993:   struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {};
deba@1993: 
deba@1993: 
deba@1993:   template <bool B, class T = void>
deba@1993:   struct disable_if_c {
deba@1993:     typedef T type;
deba@1993:   };
deba@1993: 
deba@1993:   template <class T>
deba@1993:   struct disable_if_c<true, T> {};
deba@1993: 
deba@1993:   template <class Cond, class T = void> 
deba@1993:   struct disable_if : public disable_if_c<Cond::value, T> {};
deba@1993: 
deba@1993:   template <bool B, class T>
deba@1993:   struct lazy_disable_if_c {
deba@1993:     typedef typename T::type type;
deba@1993:   };
deba@1993: 
deba@1993:   template <class T>
deba@1993:   struct lazy_disable_if_c<true, T> {};
deba@1993: 
deba@1993:   template <class Cond, class T> 
deba@1993:   struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {};
deba@1993: 
deba@1993: } // namespace lemon
deba@1993: 
deba@1993: #endif