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