1 /* $NetBSD: alloc.c,v 1.6 2004/07/07 19:20:09 mycroft Exp $ */ 2 3 /* 4 * Copyright (c) 2002 Marc Espie. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS 16 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 18 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBSD 19 * PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 21 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 /* 29 * area-based allocation built on malloc/free 30 */ 31 32 #include "sh.h" 33 34 struct link { 35 struct link *prev; 36 struct link *next; 37 }; 38 39 Area * 40 ainit(Area *ap) 41 { 42 ap->freelist = NULL; 43 return ap; 44 } 45 46 void 47 afreeall(Area *ap) 48 { 49 struct link *l, *l2; 50 51 for (l = ap->freelist; l != NULL; l = l2) { 52 l2 = l->next; 53 free(l); 54 } 55 ap->freelist = NULL; 56 } 57 58 #define L2P(l) ( (void *)(((char *)(l)) + sizeof(struct link)) ) 59 #define P2L(p) ( (struct link *)(((char *)(p)) - sizeof(struct link)) ) 60 61 void * 62 alloc(size_t size, Area *ap) 63 { 64 struct link *l; 65 66 l = malloc(sizeof(struct link) + size); 67 if (l == NULL) 68 internal_errorf(1, "unable to allocate memory"); 69 l->next = ap->freelist; 70 l->prev = NULL; 71 if (ap->freelist) 72 ap->freelist->prev = l; 73 ap->freelist = l; 74 75 return L2P(l); 76 } 77 78 void * 79 aresize(void *ptr, size_t size, Area *ap) 80 { 81 struct link *l, *l2, *lprev, *lnext; 82 83 if (ptr == NULL) 84 return alloc(size, ap); 85 86 l = P2L(ptr); 87 lprev = l->prev; 88 lnext = l->next; 89 90 l2 = realloc(l, sizeof(struct link) + size); 91 if (l2 == NULL) 92 internal_errorf(1, "unable to allocate memory"); 93 if (lprev) 94 lprev->next = l2; 95 else 96 ap->freelist = l2; 97 if (lnext) 98 lnext->prev = l2; 99 100 return L2P(l2); 101 } 102 103 void 104 afree(void *ptr, Area *ap) 105 { 106 struct link *l; 107 108 if (!ptr) 109 return; 110 111 l = P2L(ptr); 112 113 if (l->prev) 114 l->prev->next = l->next; 115 else 116 ap->freelist = l->next; 117 if (l->next) 118 l->next->prev = l->prev; 119 120 free(l); 121 } 122