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/*
 * Project: S.Ha.R.K.
 *
 * Coordinators:
 *   Giorgio Buttazzo    <giorgio@sssup.it>
 *   Paolo Gai           <pj@gandalf.sssup.it>
 *
 * Authors     :
 *   Paolo Gai           <pj@gandalf.sssup.it>
 *   (see the web pages for full authors list)
 *
 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
 *
 * http://www.sssup.it
 * http://retis.sssup.it
 * http://shark.sssup.it
 */

/**
 ------------
 CVS :        $Id: alloc.c,v 1.1.1.1 2002-03-29 14:12:52 pj Exp $

 File:        $File$
 Revision:    $Revision: 1.1.1.1 $
 Last update: $Date: 2002-03-29 14:12:52 $
 ------------

this code is from:
List-based Memory Management, from OsKit.

**/

/*
 * Copyright (C) 2000 Paolo Gai
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

/*
 * Copyright (c) 1995-1996, 1998-1999 University of Utah and the Flux Group.
 * All rights reserved.
 *
 * This file is part of the Flux OSKit.  The OSKit is free software, also known
 * as "open source;" you can redistribute it and/or modify it under the terms
 * of the GNU General Public License (GPL), version 2, as published by the Free
 * Software Foundation (FSF).  To explore alternate licensing terms, contact
 * the University of Utah at csl-dist@cs.utah.edu or +1-801-585-3271.
 *
 * The OSKit 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 GPL for more details.  You should have
 * received a copy of the GPL along with the OSKit; see the file COPYING.  If
 * not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
 */

#include <kernel/lmm.h>
#define assert(test) assertk(test)

void *lmm_alloc(lmm_t *lmm, size_t size, lmm_flags_t flags)
{
        struct lmm_region *reg;

        assert(lmm != 0);
        assert(size > 0);

        size = (size + ALIGN_MASK) & ~ALIGN_MASK;

        for (reg = lmm->regions; reg; reg = reg->next)
        {
                struct lmm_node **nodep, *node;

                CHECKREGPTR(reg);

                if (flags & ~reg->flags)
                        continue;

                for (nodep = &reg->nodes;
                     (node = *nodep) != 0;
                     nodep = &node->next)
                {
                        assert(((DWORD)node & ALIGN_MASK) == 0);
                        assert(((DWORD)node->size & ALIGN_MASK) == 0);
                        assert((node->next == 0) || (node->next > node));
                        assert((DWORD)node < reg->max);

                        if (node->size >= size)
                        {
                                if (node->size > size)
                                {
                                        struct lmm_node *newnode;

                                        /* Split the node and return its head */
                                        newnode = (struct lmm_node*)
                                                        ((void*)node + size);
                                        newnode->next = node->next;
                                        newnode->size = node->size - size;
                                        *nodep = newnode;
                                }
                                else
                                {
                                        /* Remove and return the entire node. */
                                        *nodep = node->next;
                                }

                                /* Adjust the region's free memory counter.  */
                                assert(reg->free >= size);
                                reg->free -= size;

                                return (void*)node;
                        }
                }
        }

        return 0;
}