deba@416: /* -*- mode: C++; indent-tabs-mode: nil; -*-
deba@414:  *
deba@416:  * This file is a part of LEMON, a generic C++ optimization library.
deba@414:  *
alpar@440:  * Copyright (C) 2003-2009
deba@414:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
deba@414:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
deba@414:  *
deba@414:  * Permission to use, modify and distribute this software is granted
deba@414:  * provided that this copyright notice appears in all copies. For
deba@414:  * precise terms see the accompanying LICENSE file.
deba@414:  *
deba@414:  * This software is provided "AS IS" with no warranty of any kind,
deba@414:  * express or implied, and with no claim as to its suitability for any
deba@414:  * purpose.
deba@414:  *
deba@414:  */
deba@414: 
deba@414: #ifndef LEMON_BITS_VARIANT_H
deba@414: #define LEMON_BITS_VARIANT_H
deba@414: 
deba@414: #include <lemon/assert.h>
deba@414: 
kpeter@431: // \file
kpeter@431: // \brief Variant types
deba@414: 
deba@414: namespace lemon {
deba@414: 
deba@414:   namespace _variant_bits {
deba@416: 
deba@414:     template <int left, int right>
deba@414:     struct CTMax {
deba@414:       static const int value = left < right ? right : left;
deba@414:     };
deba@414: 
deba@414:   }
deba@414: 
deba@414: 
kpeter@431:   // \brief Simple Variant type for two types
kpeter@431:   //
kpeter@431:   // Simple Variant type for two types. The Variant type is a type-safe
kpeter@431:   // union. C++ has strong limitations for using unions, for
kpeter@431:   // example you cannot store a type with non-default constructor or
kpeter@431:   // destructor in a union. This class always knowns the current
kpeter@431:   // state of the variant and it cares for the proper construction
kpeter@431:   // and destruction.
deba@414:   template <typename _First, typename _Second>
deba@414:   class BiVariant {
deba@414:   public:
deba@414: 
kpeter@431:     // \brief The \c First type.
deba@414:     typedef _First First;
kpeter@431:     // \brief The \c Second type.
deba@414:     typedef _Second Second;
deba@414: 
kpeter@431:     // \brief Constructor
kpeter@431:     //
kpeter@431:     // This constructor initalizes to the default value of the \c First
kpeter@431:     // type.
deba@414:     BiVariant() {
deba@414:       flag = true;
deba@414:       new(reinterpret_cast<First*>(data)) First();
deba@414:     }
deba@414: 
kpeter@431:     // \brief Constructor
kpeter@431:     //
kpeter@431:     // This constructor initalizes to the given value of the \c First
kpeter@431:     // type.
deba@414:     BiVariant(const First& f) {
deba@414:       flag = true;
deba@414:       new(reinterpret_cast<First*>(data)) First(f);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Constructor
kpeter@431:     //
kpeter@431:     // This constructor initalizes to the given value of the \c
kpeter@431:     // Second type.
deba@414:     BiVariant(const Second& s) {
deba@414:       flag = false;
deba@414:       new(reinterpret_cast<Second*>(data)) Second(s);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Copy constructor
kpeter@431:     //
kpeter@431:     // Copy constructor
deba@414:     BiVariant(const BiVariant& bivariant) {
deba@414:       flag = bivariant.flag;
deba@414:       if (flag) {
deba@416:         new(reinterpret_cast<First*>(data)) First(bivariant.first());
deba@414:       } else {
deba@416:         new(reinterpret_cast<Second*>(data)) Second(bivariant.second());
deba@414:       }
deba@414:     }
deba@414: 
kpeter@431:     // \brief Destrcutor
kpeter@431:     //
kpeter@431:     // Destructor
deba@414:     ~BiVariant() {
deba@414:       destroy();
deba@414:     }
deba@414: 
kpeter@431:     // \brief Set to the default value of the \c First type.
kpeter@431:     //
kpeter@431:     // This function sets the variant to the default value of the \c
kpeter@431:     // First type.
deba@414:     BiVariant& setFirst() {
deba@414:       destroy();
deba@414:       flag = true;
deba@416:       new(reinterpret_cast<First*>(data)) First();
deba@414:       return *this;
deba@414:     }
deba@414: 
kpeter@431:     // \brief Set to the given value of the \c First type.
kpeter@431:     //
kpeter@431:     // This function sets the variant to the given value of the \c
kpeter@431:     // First type.
deba@414:     BiVariant& setFirst(const First& f) {
deba@414:       destroy();
deba@414:       flag = true;
deba@416:       new(reinterpret_cast<First*>(data)) First(f);
deba@414:       return *this;
deba@414:     }
deba@414: 
kpeter@431:     // \brief Set to the default value of the \c Second type.
kpeter@431:     //
kpeter@431:     // This function sets the variant to the default value of the \c
kpeter@431:     // Second type.
deba@414:     BiVariant& setSecond() {
deba@414:       destroy();
deba@414:       flag = false;
deba@416:       new(reinterpret_cast<Second*>(data)) Second();
deba@414:       return *this;
deba@414:     }
deba@414: 
kpeter@431:     // \brief Set to the given value of the \c Second type.
kpeter@431:     //
kpeter@431:     // This function sets the variant to the given value of the \c
kpeter@431:     // Second type.
deba@414:     BiVariant& setSecond(const Second& s) {
deba@414:       destroy();
deba@414:       flag = false;
deba@416:       new(reinterpret_cast<Second*>(data)) Second(s);
deba@414:       return *this;
deba@414:     }
deba@414: 
kpeter@431:     // \brief Operator form of the \c setFirst()
deba@414:     BiVariant& operator=(const First& f) {
deba@414:       return setFirst(f);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Operator form of the \c setSecond()
deba@414:     BiVariant& operator=(const Second& s) {
deba@414:       return setSecond(s);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Assign operator
deba@414:     BiVariant& operator=(const BiVariant& bivariant) {
deba@414:       if (this == &bivariant) return *this;
deba@414:       destroy();
deba@414:       flag = bivariant.flag;
deba@414:       if (flag) {
deba@416:         new(reinterpret_cast<First*>(data)) First(bivariant.first());
deba@414:       } else {
deba@416:         new(reinterpret_cast<Second*>(data)) Second(bivariant.second());
deba@414:       }
deba@414:       return *this;
deba@414:     }
deba@414: 
kpeter@431:     // \brief Reference to the value
kpeter@431:     //
kpeter@431:     // Reference to the value of the \c First type.
kpeter@431:     // \pre The BiVariant should store value of \c First type.
deba@414:     First& first() {
deba@414:       LEMON_DEBUG(flag, "Variant wrong state");
kpeter@431:       return *reinterpret_cast<First*>(data);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Const reference to the value
kpeter@431:     //
kpeter@431:     // Const reference to the value of the \c First type.
kpeter@431:     // \pre The BiVariant should store value of \c First type.
kpeter@431:     const First& first() const {
deba@414:       LEMON_DEBUG(flag, "Variant wrong state");
kpeter@431:       return *reinterpret_cast<const First*>(data);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Operator form of the \c first()
deba@414:     operator First&() { return first(); }
kpeter@431:     // \brief Operator form of the const \c first()
deba@414:     operator const First&() const { return first(); }
deba@414: 
kpeter@431:     // \brief Reference to the value
kpeter@431:     //
kpeter@431:     // Reference to the value of the \c Second type.
kpeter@431:     // \pre The BiVariant should store value of \c Second type.
kpeter@431:     Second& second() {
deba@414:       LEMON_DEBUG(!flag, "Variant wrong state");
kpeter@431:       return *reinterpret_cast<Second*>(data);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Const reference to the value
kpeter@431:     //
kpeter@431:     // Const reference to the value of the \c Second type.
kpeter@431:     // \pre The BiVariant should store value of \c Second type.
kpeter@431:     const Second& second() const {
deba@414:       LEMON_DEBUG(!flag, "Variant wrong state");
kpeter@431:       return *reinterpret_cast<const Second*>(data);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Operator form of the \c second()
deba@414:     operator Second&() { return second(); }
kpeter@431:     // \brief Operator form of the const \c second()
deba@414:     operator const Second&() const { return second(); }
deba@414: 
kpeter@431:     // \brief %True when the variant is in the first state
kpeter@431:     //
kpeter@431:     // %True when the variant stores value of the \c First type.
deba@414:     bool firstState() const { return flag; }
deba@414: 
kpeter@431:     // \brief %True when the variant is in the second state
kpeter@431:     //
kpeter@431:     // %True when the variant stores value of the \c Second type.
deba@414:     bool secondState() const { return !flag; }
deba@414: 
deba@414:   private:
deba@414: 
deba@414:     void destroy() {
deba@414:       if (flag) {
deba@414:         reinterpret_cast<First*>(data)->~First();
deba@414:       } else {
deba@414:         reinterpret_cast<Second*>(data)->~Second();
deba@414:       }
deba@414:     }
deba@416: 
deba@414:     char data[_variant_bits::CTMax<sizeof(First), sizeof(Second)>::value];
deba@414:     bool flag;
deba@414:   };
deba@414: 
deba@414:   namespace _variant_bits {
deba@416: 
deba@414:     template <int _idx, typename _TypeMap>
deba@414:     struct Memory {
deba@414: 
deba@414:       typedef typename _TypeMap::template Map<_idx>::Type Current;
deba@414: 
deba@414:       static void destroy(int index, char* place) {
deba@414:         if (index == _idx) {
deba@414:           reinterpret_cast<Current*>(place)->~Current();
deba@414:         } else {
deba@414:           Memory<_idx - 1, _TypeMap>::destroy(index, place);
deba@414:         }
deba@414:       }
deba@414: 
deba@414:       static void copy(int index, char* to, const char* from) {
deba@414:         if (index == _idx) {
deba@414:           new (reinterpret_cast<Current*>(to))
deba@414:             Current(reinterpret_cast<const Current*>(from));
deba@414:         } else {
deba@414:           Memory<_idx - 1, _TypeMap>::copy(index, to, from);
deba@414:         }
deba@414:       }
deba@414: 
deba@414:     };
deba@414: 
deba@414:     template <typename _TypeMap>
deba@414:     struct Memory<-1, _TypeMap> {
deba@414: 
deba@414:       static void destroy(int, char*) {
deba@414:         LEMON_DEBUG(false, "Variant wrong index.");
deba@414:       }
deba@414: 
deba@414:       static void copy(int, char*, const char*) {
deba@414:         LEMON_DEBUG(false, "Variant wrong index.");
deba@414:       }
deba@414:     };
deba@414: 
deba@414:     template <int _idx, typename _TypeMap>
deba@414:     struct Size {
deba@416:       static const int value =
deba@416:       CTMax<sizeof(typename _TypeMap::template Map<_idx>::Type),
deba@414:             Size<_idx - 1, _TypeMap>::value>::value;
deba@414:     };
deba@414: 
deba@414:     template <typename _TypeMap>
deba@414:     struct Size<0, _TypeMap> {
deba@416:       static const int value =
deba@414:       sizeof(typename _TypeMap::template Map<0>::Type);
deba@414:     };
deba@414: 
deba@414:   }
deba@414: 
kpeter@431:   // \brief Variant type
kpeter@431:   //
kpeter@431:   // Simple Variant type. The Variant type is a type-safe union.
kpeter@431:   // C++ has strong limitations for using unions, for example you
kpeter@431:   // cannot store type with non-default constructor or destructor in
kpeter@431:   // a union. This class always knowns the current state of the
kpeter@431:   // variant and it cares for the proper construction and
kpeter@431:   // destruction.
kpeter@431:   //
kpeter@431:   // \param _num The number of the types which can be stored in the
kpeter@431:   // variant type.
kpeter@431:   // \param _TypeMap This class describes the types of the Variant. The
kpeter@431:   // _TypeMap::Map<index>::Type should be a valid type for each index
kpeter@431:   // in the range {0, 1, ..., _num - 1}. The \c VariantTypeMap is helper
kpeter@431:   // class to define such type mappings up to 10 types.
kpeter@431:   //
kpeter@431:   // And the usage of the class:
kpeter@431:   //\code
kpeter@431:   // typedef Variant<3, VariantTypeMap<int, std::string, double> > MyVariant;
kpeter@431:   // MyVariant var;
kpeter@431:   // var.set<0>(12);
kpeter@431:   // std::cout << var.get<0>() << std::endl;
kpeter@431:   // var.set<1>("alpha");
kpeter@431:   // std::cout << var.get<1>() << std::endl;
kpeter@431:   // var.set<2>(0.75);
kpeter@431:   // std::cout << var.get<2>() << std::endl;
kpeter@431:   //\endcode
kpeter@431:   //
kpeter@431:   // The result of course:
kpeter@431:   //\code
kpeter@431:   // 12
kpeter@431:   // alpha
kpeter@431:   // 0.75
kpeter@431:   //\endcode
deba@414:   template <int _num, typename _TypeMap>
deba@414:   class Variant {
deba@414:   public:
deba@414: 
deba@414:     static const int num = _num;
deba@414: 
deba@414:     typedef _TypeMap TypeMap;
deba@414: 
kpeter@431:     // \brief Constructor
kpeter@431:     //
kpeter@431:     // This constructor initalizes to the default value of the \c type
kpeter@431:     // with 0 index.
deba@414:     Variant() {
deba@414:       flag = 0;
deba@416:       new(reinterpret_cast<typename TypeMap::template Map<0>::Type*>(data))
deba@414:         typename TypeMap::template Map<0>::Type();
deba@414:     }
deba@414: 
deba@414: 
kpeter@431:     // \brief Copy constructor
kpeter@431:     //
kpeter@431:     // Copy constructor
deba@414:     Variant(const Variant& variant) {
deba@414:       flag = variant.flag;
deba@414:       _variant_bits::Memory<num - 1, TypeMap>::copy(flag, data, variant.data);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Assign operator
kpeter@431:     //
kpeter@431:     // Assign operator
deba@414:     Variant& operator=(const Variant& variant) {
deba@414:       if (this == &variant) return *this;
deba@414:       _variant_bits::Memory<num - 1, TypeMap>::
deba@414:         destroy(flag, data);
deba@414:       flag = variant.flag;
deba@414:       _variant_bits::Memory<num - 1, TypeMap>::
deba@414:         copy(flag, data, variant.data);
deba@414:       return *this;
deba@414:     }
deba@414: 
kpeter@431:     // \brief Destrcutor
kpeter@431:     //
kpeter@431:     // Destructor
deba@414:     ~Variant() {
deba@414:       _variant_bits::Memory<num - 1, TypeMap>::destroy(flag, data);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Set to the default value of the type with \c _idx index.
kpeter@431:     //
kpeter@431:     // This function sets the variant to the default value of the
kpeter@431:     // type with \c _idx index.
deba@414:     template <int _idx>
deba@414:     Variant& set() {
deba@414:       _variant_bits::Memory<num - 1, TypeMap>::destroy(flag, data);
deba@414:       flag = _idx;
deba@416:       new(reinterpret_cast<typename TypeMap::template Map<_idx>::Type*>(data))
deba@414:         typename TypeMap::template Map<_idx>::Type();
deba@414:       return *this;
deba@414:     }
deba@414: 
kpeter@431:     // \brief Set to the given value of the type with \c _idx index.
kpeter@431:     //
kpeter@431:     // This function sets the variant to the given value of the type
kpeter@431:     // with \c _idx index.
deba@414:     template <int _idx>
deba@414:     Variant& set(const typename _TypeMap::template Map<_idx>::Type& init) {
deba@414:       _variant_bits::Memory<num - 1, TypeMap>::destroy(flag, data);
deba@414:       flag = _idx;
deba@416:       new(reinterpret_cast<typename TypeMap::template Map<_idx>::Type*>(data))
deba@414:         typename TypeMap::template Map<_idx>::Type(init);
deba@414:       return *this;
deba@414:     }
deba@414: 
kpeter@431:     // \brief Gets the current value of the type with \c _idx index.
kpeter@431:     //
kpeter@431:     // Gets the current value of the type with \c _idx index.
deba@414:     template <int _idx>
deba@414:     const typename TypeMap::template Map<_idx>::Type& get() const {
deba@414:       LEMON_DEBUG(_idx == flag, "Variant wrong index");
deba@414:       return *reinterpret_cast<const typename TypeMap::
deba@416:         template Map<_idx>::Type*>(data);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Gets the current value of the type with \c _idx index.
kpeter@431:     //
kpeter@431:     // Gets the current value of the type with \c _idx index.
deba@414:     template <int _idx>
deba@414:     typename _TypeMap::template Map<_idx>::Type& get() {
deba@414:       LEMON_DEBUG(_idx == flag, "Variant wrong index");
deba@414:       return *reinterpret_cast<typename TypeMap::template Map<_idx>::Type*>
deba@416:         (data);
deba@414:     }
deba@414: 
kpeter@431:     // \brief Returns the current state of the variant.
kpeter@431:     //
kpeter@431:     // Returns the current state of the variant.
deba@414:     int state() const {
deba@414:       return flag;
deba@414:     }
deba@414: 
deba@414:   private:
deba@416: 
deba@414:     char data[_variant_bits::Size<num - 1, TypeMap>::value];
deba@414:     int flag;
deba@414:   };
deba@414: 
deba@414:   namespace _variant_bits {
deba@414: 
deba@414:     template <int _index, typename _List>
deba@414:     struct Get {
deba@414:       typedef typename Get<_index - 1, typename _List::Next>::Type Type;
deba@414:     };
deba@414: 
deba@414:     template <typename _List>
deba@414:     struct Get<0, _List> {
deba@414:       typedef typename _List::Type Type;
deba@414:     };
deba@414: 
deba@414:     struct List {};
deba@416: 
deba@414:     template <typename _Type, typename _List>
deba@414:     struct Insert {
deba@414:       typedef _List Next;
deba@414:       typedef _Type Type;
deba@414:     };
deba@414: 
deba@416:     template <int _idx, typename _T0, typename _T1, typename _T2,
kpeter@430:               typename _T3, typename _T4, typename _T5, typename _T6,
deba@414:               typename _T7, typename _T8, typename _T9>
deba@414:     struct Mapper {
deba@414:       typedef List L10;
deba@414:       typedef Insert<_T9, L10> L9;
deba@414:       typedef Insert<_T8, L9> L8;
deba@414:       typedef Insert<_T7, L8> L7;
deba@414:       typedef Insert<_T6, L7> L6;
deba@414:       typedef Insert<_T5, L6> L5;
deba@414:       typedef Insert<_T4, L5> L4;
deba@414:       typedef Insert<_T3, L4> L3;
deba@414:       typedef Insert<_T2, L3> L2;
deba@414:       typedef Insert<_T1, L2> L1;
deba@414:       typedef Insert<_T0, L1> L0;
deba@414:       typedef typename Get<_idx, L0>::Type Type;
deba@414:     };
deba@416: 
deba@414:   }
deba@414: 
kpeter@431:   // \brief Helper class for Variant
kpeter@431:   //
kpeter@431:   // Helper class to define type mappings for Variant. This class
kpeter@431:   // converts the template parameters to be mappable by integer.
kpeter@431:   // \see Variant
deba@414:   template <
deba@416:     typename _T0,
deba@414:     typename _T1 = void, typename _T2 = void, typename _T3 = void,
kpeter@430:     typename _T4 = void, typename _T5 = void, typename _T6 = void,
deba@414:     typename _T7 = void, typename _T8 = void, typename _T9 = void>
deba@414:   struct VariantTypeMap {
deba@414:     template <int _idx>
deba@414:     struct Map {
deba@414:       typedef typename _variant_bits::
deba@414:       Mapper<_idx, _T0, _T1, _T2, _T3, _T4, _T5, _T6, _T7, _T8, _T9>::Type
deba@414:       Type;
deba@414:     };
deba@414:   };
deba@416: 
deba@414: }
deba@414: 
deba@414: 
deba@414: #endif