mapnik/include/mapnik/utils.hpp
2014-11-20 15:25:50 +01:00

170 lines
4.1 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2014 Artem Pavlenko
*
* This library 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 2.1 of the License, or (at your option) any later version.
*
* This library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
#ifndef MAPNIK_UTILS_HPP
#define MAPNIK_UTILS_HPP
#include <mapnik/config.hpp>
#include <mapnik/unique_lock.hpp>
// stl
#include <stdexcept> // std::runtime_error
#include <cstdlib> // std::atexit
#include <new> // operator new
#ifdef MAPNIK_THREADSAFE
#include <mutex>
#endif
namespace mapnik
{
template <typename T>
class CreateUsingNew
{
public:
static T* create()
{
return new T;
}
static void destroy(T* obj)
{
delete obj;
}
};
template <typename T>
class CreateStatic
{
private:
union MaxAlign
{
char t_[sizeof(T)];
short int shortInt_;
int int_;
long int longInt_;
float float_;
double double_;
long double longDouble_;
struct Test;
int Test::* pMember_;
int (Test::*pMemberFn_)(int);
};
public:
static T* create()
{
static MaxAlign staticMemory;
return new(&staticMemory) T;
}
static void destroy(volatile T* obj)
{
obj->~T();
}
};
#ifdef __GNUC__
template <typename T,
template <typename U> class CreatePolicy=CreateStatic> class MAPNIK_DECL singleton
{
#else
template <typename T,
template <typename U> class CreatePolicy=CreateStatic> class singleton
{
#endif
friend class CreatePolicy<T>;
static T* pInstance_;
static bool destroyed_;
singleton(const singleton &rhs);
singleton& operator=(const singleton&);
static void onDeadReference()
{
throw std::runtime_error("dead reference!");
}
static void DestroySingleton()
{
CreatePolicy<T>::destroy(pInstance_);
pInstance_ = 0;
destroyed_ = true;
}
protected:
#ifdef MAPNIK_THREADSAFE
static std::mutex mutex_;
#endif
singleton() {}
public:
static T& instance()
{
if (! pInstance_)
{
#ifdef MAPNIK_THREADSAFE
mapnik::scoped_lock lock(mutex_);
#endif
if (! pInstance_)
{
if (destroyed_)
{
destroyed_ = false;
onDeadReference();
}
else
{
pInstance_ = CreatePolicy<T>::create();
// register destruction
std::atexit(&DestroySingleton);
}
}
}
return *pInstance_;
}
};
#ifdef MAPNIK_THREADSAFE
template <typename T,
template <typename U> class CreatePolicy> std::mutex singleton<T,CreatePolicy>::mutex_;
#endif
template <typename T,
template <typename U> class CreatePolicy> T* singleton<T,CreatePolicy>::pInstance_=0;
template <typename T,
template <typename U> class CreatePolicy> bool singleton<T,CreatePolicy>::destroyed_=false;
#ifdef _WINDOWS
// UTF8 <--> UTF16 conversion routines
MAPNIK_DECL std::string utf16_to_utf8(std::wstring const& wstr);
MAPNIK_DECL std::wstring utf8_to_utf16(std::string const& str);
#endif // _WINDOWS
}
#endif // MAPNIK_UTILS_HPP