libreoffice/connectivity/source/drivers/postgresql/pq_allocator.hxx

/* -*- Mode: C++; eval:(c-set-style "bsd"); tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*************************************************************************
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License version 2.1, as published by the Free Software Foundation.
 *
 *  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., 59 Temple Place, Suite 330, Boston,
 *  MA  02111-1307  USA
 *
 *  The Initial Developer of the Original Code is: Sun Microsystems, Inc.
 *
 *  Copyright: 2002 by Sun Microsystems, Inc.
 *             2011 Lionel Elie Mamane <lionel@mamane.lu>
 *
 *  All Rights Reserved.
 *
 *  Contributor(s): _______________________________________
 *
 ************************************************************************/

#ifndef _PQ_ALLOCATOR_
#define _PQ_ALLOCATOR_

#include <cstddef>
#include "sal/types.h"

#include "pq_common.hxx"

/** jbu: This source has been copied from sal/inc/internal/allocator.hxx,
         because it is not a public interface. Thx a lot for figuring this
         out.
 */

//######################################################
// This is no general purpose STL allocator but one
// necessary to use STL for some implementation but
// avoid linking sal against the STLPort library!!!
// For more information on when and how to define a
// custom stl allocator have a look at Scott Meyers:
// "Effective STL", Nicolai M. Josuttis:
// "The C++ Standard Library - A Tutorial and Reference"
// and at http://www.josuttis.com/cppcode/allocator.html

namespace pq_sdbc_driver {

template<class T>
class Allocator
{
public:
    typedef T value_type;
    typedef T* pointer;
    typedef const T* const_pointer;
    typedef T& reference;
    typedef const T& const_reference;
    typedef ::std::size_t size_type;
    typedef ::std::ptrdiff_t difference_type;

    //-----------------------------------------
    template<class U>
    struct rebind
    {
        typedef Allocator<U> other;
    };

    //-----------------------------------------
    pointer address (reference value) const
    {
        return &value;
    }

    //-----------------------------------------
    const_pointer address (const_reference value) const
    {
        return &value;
    }

    //-----------------------------------------
    Allocator() SAL_THROW(())
    {}

    //-----------------------------------------
    template<class U>
    Allocator (const Allocator<U>&) SAL_THROW(())
    {}

    //-----------------------------------------
    Allocator(const Allocator&) SAL_THROW(())
    {}

    //-----------------------------------------
    ~Allocator() SAL_THROW(())
    {}

    //-----------------------------------------
    size_type max_size() const SAL_THROW(())
    {
        return size_type(-1)/sizeof(T);
    }

    //-----------------------------------------
    /* Normally the code for allocate should
       throw a std::bad_alloc exception if the
       requested memory could not be allocated:
       (C++ standard 20.4.1.1):

       pointer allocate (size_type n, const void* hint = 0)
       {
         pointer p = reinterpret_cast<pointer>(
             rtl_allocateMemory(sal_uInt32(n * sizeof(T))));

         if (NULL == p)
             throw ::std::bad_alloc();

         return p;
       }

       but some compilers do not compile it if exceptions
       are not enabled, e.g. GCC under Linux and it is
       in general not desired to compile sal with exceptions
       enabled. */
    pointer allocate (size_type n, const void* UNUSED(hint) = 0)
    {
        return reinterpret_cast<pointer>(
            rtl_allocateMemory(sal_uInt32(n * sizeof(T))));
    }

    //-----------------------------------------
    void deallocate (pointer p, size_type UNUSED(n))
    {
        rtl_freeMemory(p);
    }

    //-----------------------------------------
    void construct (pointer p, const T& value)
    {
        new ((void*)p)T(value);
    }

    // LEM: GNU libstdc++ vectors expect this one to exist,
    // at least if one intends to create vectors by giving
    // only a size and no initialising value.
    //-----------------------------------------
    void construct (pointer p)
    {
        new ((void*)p)T;
    }

    //-----------------------------------------
    void destroy (pointer p)
    {
        p->~T();
    }
};

//######################################################
// Custom STL allocators must be stateless (see
// references above) that's why the operators below
// return always true or false
template<class T, class U>
inline bool operator== (const Allocator<T>&, const Allocator<U>&) SAL_THROW(())
{
    return true;
}

template<class T, class U>
inline bool operator!= (const Allocator<T>&, const Allocator<U>&) SAL_THROW(())
{
    return false;
}

} /* namespace sal */

//######################################################
/* REQUIRED BY STLPort (see stlport '_alloc.h'):
   Hack for compilers that do not support member
   template classes (e.g. MSVC 6) */
#if defined (_MSC_VER)
#if (_MSC_VER < 1400) // MSVC 6
namespace _STL
{
#endif
#endif
    template<class T, class U>
    inline pq_sdbc_driver::Allocator<U> & __stl_alloc_rebind (
        pq_sdbc_driver::Allocator<T> & a, U const *)
    {
        return (pq_sdbc_driver::Allocator<U>&)(a);
    }
#if defined (_MSC_VER)
#if (_MSC_VER < 1400) // MSVC 6
}
#endif
#endif

#endif /* _PQ_ALLOCATOR_ */