// Documentation link:

// https://sourcemaking.com/design_patterns/singleton/cpp/1

#include "threadsettinginterface.h"

#include <memory>

// This class is designed to instanciate of singleton object

class ThreadSetting : public ThreadSettingInterface

{

unsigned m_nbThread;

static const unsigned m_nbThreadMax = 4;

static ThreadSetting* s_instance;

// As the ctor is private, is class cannot be instanciate else than through

// its static method 'instance()'

ThreadSetting(unsigned v = 0)

{

SetNbThread(v);

}

public:

unsigned GetNbThread() const

{

return m_nbThread;

}

void SetNbThread(unsigned v)

{

if (v == 0)

v = m_nbThreadMax;

m_nbThread = (v <= m_nbThreadMax) ? v : m_nbThreadMax;

}

static ThreadSetting* instance()

{

if (!s_instance)

s_instance = new ThreadSetting;

return s_instance;

}

};

ThreadSettingInterface* ThreadSettingInterface::instance()

{

return ThreadSetting::instance();

}

// Allocating and initializing ThreadSetting's static data member.

// The pointer is being allocated - not the object inself.

ThreadSetting *ThreadSetting::s_instance = 0;