pip/libs/main/core/pivariantsimple.h

/*! \file pivariantsimple.h
 * \brief Variant simple type
 *
 * This file declares PIVariantSimple
*/
/*
	PIP - Platform Independent Primitives
	Variant simple type
	Ivan Pelipenko peri4ko@yandex.ru

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Lesser General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program 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 Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef PIVARIANTSIMPLE_H
#define PIVARIANTSIMPLE_H

#include "pistring.h"
#include <typeinfo>


class __VariantFunctionsBase__ {
public:
	virtual __VariantFunctionsBase__ * instance() {return 0;}
	virtual PIString typeName() const {return PIString();}
	virtual uint hash() const {return 0;}
	virtual void newT(void *& ptr, const void * value) {;}
	virtual void newNullT(void *& ptr) {;}
	virtual void assignT(void *& ptr, const void * value) {;}
	virtual void deleteT(void *& ptr) {;}
	//virtual PIByteArray toData(const void * ptr) const {return PIByteArray();}
	//virtual void fromData(void *& ptr, PIByteArray ba) {;}
	static PIMap<uint, __VariantFunctionsBase__*> & registered() {static PIMap<uint, __VariantFunctionsBase__*> ret; return ret;}
};


template<typename T>
class __VariantFunctions__: public __VariantFunctionsBase__ {
public:
	__VariantFunctionsBase__ * instance() final {static __VariantFunctions__<T> ret; return &ret;}
	PIString typeName() const final {static PIString ret(typeid(T).name()); return ret;}
	uint hash() const final {static uint ret = typeName().hash(); return ret;}
	void newT(void *& ptr, const void * value) final {ptr = (void*)(new T(*(const T*)value)); /*printf(" * new\n")*/;}
	void newNullT(void *& ptr) final {ptr = (void*)(new T());/* printf(" * new null\n")*/;}
	void assignT(void *& ptr, const void * value) final {*(T*)ptr = *(const T*)value; /*printf(" * =\n")*/;}
	void deleteT(void *& ptr) final {delete (T*)(ptr); /*printf(" * del\n")*/;}
	//PIByteArray toData(const void * ptr) const final {PIByteArray ret; ret << (*(const T* &)ptr); return ret;}
	//void fromData(void *& ptr, PIByteArray ba) final {ba >> *(T*)ptr;}
};

class PIVariantSimple {
public:
	PIVariantSimple() {ptr = 0; f = 0;}
	PIVariantSimple(const PIVariantSimple & v) {
		ptr = 0;
		f = v.f;
		if (f && v.ptr)
			f->newT(ptr, v.ptr);
	}
	~PIVariantSimple() {destroy();}

	PIVariantSimple & operator=(const PIVariantSimple & v) {
		destroy();
		f = v.f;
		if (f && v.ptr)
			f->newT(ptr, v.ptr);
		return *this;
	}

	template <typename T>
	void setValue(const T & v) {
		if (f) {
			if (isMyType<T>()) {
				f->assignT(ptr, (const void *)&v);
				return;
			}
		}
		destroy();
		f = __VariantFunctions__<T>().instance();
		f->newT(ptr, (const void *)&v);
	}

	template <typename T>
	T value() const {
		if (!f) return T();
		if (!isMyType<T>())
			return T();
		return *(T*)(ptr);
	}

	template <typename T>
	static PIVariantSimple fromValue(const T & v) {
		PIVariantSimple ret;
		ret.setValue(v);
		return ret;
	}

	/*
	PIByteArray save() const {
		if (!ptr || !f) return PIByteArray();
		PIByteArray ret;
		ret << f->hash();
		ret.append(f->toData(ptr));
		return ret;
	}

	bool load(PIByteArray ba) {
		if (ba.size_s() < 4) return false;
		uint h(0); ba >> h;
		destroy();
		f = __VariantFunctionsBase__::registered().value(h, 0);
		if (!f) return false;
		f->newNullT(ptr);
		f->fromData(ptr, ba);
		return true;
	}
	*/

private:
	template <typename T>
	bool isMyType() const {
		uint mh = f->hash(), th = __VariantFunctions__<T>().instance()->hash();
		if (mh == 0 || th == 0) return false;
		return mh == th;
	}

	void destroy() {
		if (ptr && f)
			f->deleteT(ptr);
		ptr = 0;
		f = 0;
	}

	void * ptr;
	__VariantFunctionsBase__ * f;

};


#define REGISTER_PIVARIANTSIMPLE_STREAM(Type) \
	STATIC_INITIALIZER_BEGIN() \
		__VariantFunctionsBase__ * f = __VariantFunctions__<Type>().instance(); \
		__VariantFunctionsBase__::registered()[f->hash()] = f; \
	STATIC_INITIALIZER_END()



#endif // PIVARIANTSIMPLE_H