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