/* * Copyright (c) 2004, Swedish Institute of Computer Science. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the Institute nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * This file is part of the uIP TCP/IP stack * * Author: Adam Dunkels <adam@sics.se> * * $Id: memb.c,v 1.1 2006/06/12 08:21:43 adam Exp $ */ /** * \addtogroup memb * @{ */ /** * \file * Memory block allocation routines. * \author Adam Dunkels <adam@sics.se> */ #include <string.h> #include "memb.h" /*---------------------------------------------------------------------------*/ void memb_init(struct memb_blocks *m) { memset(m->count, 0, m->num); memset(m->mem, 0, m->size * m->num); } /*---------------------------------------------------------------------------*/ void * memb_alloc(struct memb_blocks *m) { int i; for(i = 0; i < m->num; ++i) { if(m->count[i] == 0) { /* If this block was unused, we increase the reference count to indicate that it now is used and return a pointer to the memory block. */ ++(m->count[i]); return (void *)((char *)m->mem + (i * m->size)); } } /* No free block was found, so we return NULL to indicate failure to allocate block. */ return NULL; } /*---------------------------------------------------------------------------*/ char memb_free(struct memb_blocks *m, void *ptr) { int i; char *ptr2; /* Walk through the list of blocks and try to find the block to which the pointer "ptr" points to. */ ptr2 = (char *)m->mem; for(i = 0; i < m->num; ++i) { if(ptr2 == (char *)ptr) { /* We've found to block to which "ptr" points so we decrease the reference count and return the new value of it. */ if(m->count[i] > 0) { /* Make sure that we don't deallocate free memory. */ --(m->count[i]); } return m->count[i]; } ptr2 += m->size; } return -1; } /*---------------------------------------------------------------------------*/ /** @} */