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/*
* 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;
}
/*---------------------------------------------------------------------------*/
/** @} */
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