//============================================================================
// Contents:
//
//  Definition of countability class member and global functions.
//
// History:
//
//  Initial version created by Kevlin Henney, kevlin@acm.org, January 1998.
//
// Permissions:
//
//  Copyright Kevlin Henney, 1998. All rights reserved.
//
//  Permission to use, copy, modify, and distribute this software for any
//  purpose is hereby granted without fee, provided that this copyright and
//  permissions notice appear in all copies and derivatives, and that no
//  charge may be made for the software and its documentation except to cover
//  cost of distribution.
//
//  This software is provided "as is" without express or implied warranty.
//
// Notes:
//
//  All the functions defined are likely candidates for explicit inlining, but
//  for the purposes of demonstration such an optimisation has not been deemed
//  necessary.
//
//  This code has been written to conform to standard C++ (in final draft
//  status at the time of writing). It has been compiled successfully using
//  the operational subset of standard features implemented by Microsoft
//  Visual C++ 5.0.
//============================================================================

#include "countability.hpp"

//----------------------------------------------------------------------------
// Description:
//
//  Definition of countability class member functions.
//
// Notes:
//
//  The implementation presented is not guaranteed to count safely across
//  threads. Threadsafe counting can be implemented either by modifying the
//  code below (eg under Win32 using InterlockedIncrement instead of ++), or
//  by providing an additional class (eg threadsafe_countability). Note that
//  in the case of modifying code in this file, not having inline functions
//  supports a binary compatible change, ie the decision as to whether or not
//  to use a threadsafe version can be deferred to link time.
//----------------------------------------------------------------------------

void countability::acquire() const
{
    ++count;
}

void countability::release() const
{
    --count;
}

size_t countability::acquired() const
{
    return count;
}

countability::countability()
  : count(0)
{
}

countability::~countability()
{
}

//----------------------------------------------------------------------------
// Description:
//
//  Definition of countability global non-template functions.
//----------------------------------------------------------------------------

void acquire(const countability *ptr)
{
    if(ptr)
    {
        ptr->acquire();
    }
}

void release(const countability *ptr)
{
    if(ptr)
    {
        ptr->release();
    }
}

size_t acquired(const countability *ptr)
{
    return ptr ? ptr->acquired() : 0;
}