1 /* 2 * Copyright (c) 2004, Swedish Institute of Computer Science. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the Institute nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * This file is part of the uIP TCP/IP stack 30 * 31 * Author: Adam Dunkels <[email protected]> 32 * 33 * $Id: memb.c,v 1.1 2006/06/12 08:21:43 adam Exp $ 34 */ 35 36 /** 37 * \addtogroup memb 38 * @{ 39 */ 40 41 /** 42 * \file 43 * Memory block allocation routines. 44 * \author Adam Dunkels <[email protected]> 45 */ 46 #include <string.h> 47 48 #include "memb.h" 49 50 /*---------------------------------------------------------------------------*/ 51 void 52 memb_init(struct memb_blocks *m) 53 { 54 memset(m->count, 0, m->num); 55 memset(m->mem, 0, m->size * m->num); 56 } 57 /*---------------------------------------------------------------------------*/ 58 void * 59 memb_alloc(struct memb_blocks *m) 60 { 61 int i; 62 63 for(i = 0; i < m->num; ++i) { 64 if(m->count[i] == 0) { 65 /* If this block was unused, we increase the reference count to 66 indicate that it now is used and return a pointer to the 67 memory block. */ 68 ++(m->count[i]); 69 return (void *)((char *)m->mem + (i * m->size)); 70 } 71 } 72 73 /* No free block was found, so we return NULL to indicate failure to 74 allocate block. */ 75 return NULL; 76 } 77 /*---------------------------------------------------------------------------*/ 78 char 79 memb_free(struct memb_blocks *m, void *ptr) 80 { 81 int i; 82 char *ptr2; 83 84 /* Walk through the list of blocks and try to find the block to 85 which the pointer "ptr" points to. */ 86 ptr2 = (char *)m->mem; 87 for(i = 0; i < m->num; ++i) { 88 89 if(ptr2 == (char *)ptr) { 90 /* We've found to block to which "ptr" points so we decrease the 91 reference count and return the new value of it. */ 92 if(m->count[i] > 0) { 93 /* Make sure that we don't deallocate free memory. */ 94 --(m->count[i]); 95 } 96 return m->count[i]; 97 } 98 ptr2 += m->size; 99 } 100 return -1; 101 } 102 /*---------------------------------------------------------------------------*/ 103 104 /** @} */ 105