IdSet.cpp

Go to the documentation of this file.

// -*- c++ -*-
//------------------------------------------------------------------------------
//                            IdSet.cpp
//------------------------------------------------------------------------------
//  Copyright (C) 1997-2002  Vladislav Grinchenko 
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Library General Public
//  License as published by the Free Software Foundation; either
//  version 2 of the License, or (at your option) any later version.
//------------------------------------------------------------------------------
 
#include "assa/Logger.h"
#include "assa/IdSet.h"
 
using namespace ASSA;
 
int
IdSet::
newid()
{
    register int i;
    register int current;
 
    trace("IdSet::newid");
 
    current = m_next_available_id++;
 
    if (m_next_available_id < FD_SETSIZE) 
    {
    // mark current id as being in use
    FD_SET(current, &m_id_set_map);
 
    // search starting from current position to the end 
    // assuming that m_next_available_id is maintained
    // to be the lowest available at all times.
 
    for (i=current+1; i<FD_SETSIZE; i++) 
    {
        if (!FD_ISSET(i, &m_id_set_map)) 
        {
        m_next_available_id = i;
        return current;
        }
    }
    // if I am here, I am out of ids
    m_next_available_id = FD_SETSIZE;
    }
    return -1;
}
 
int
IdSet::
recycle(int id_)
{
    trace("IdSet::recycle");
 
    if ( 0 <= id_ && id_ < FD_SETSIZE ) {
        FD_CLR(id_, &m_id_set_map); // mark id as free
        
        // if id is smaller then current, adjust current
        if (id_ < m_next_available_id) {
            m_next_available_id = id_;
        }
        return 0;
    }
    return -1;
}