projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| faf1dc17 | 1 | /*- |
| 80409bdc KB |
2 | * Copyright (c) 1993 |
| 3 | * The Regents of the University of California. All rights reserved. | |
| faf1dc17 KM |
4 | * |
| 5 | * This code is derived from software contributed to Berkeley by | |
| 6 | * The Mach Operating System project at Carnegie-Mellon University. | |
| 7 | * | |
| 8 | * %sccs.include.redist.c% | |
| 9 | * | |
| 80409bdc | 10 | * @(#)alloc.c 8.1 (Berkeley) %G% |
| faf1dc17 KM |
11 | * |
| 12 | * | |
| 13 | * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University | |
| 14 | * All Rights Reserved. | |
| 15 | * | |
| 16 | * Author: Alessandro Forin | |
| 17 | * | |
| 18 | * Permission to use, copy, modify and distribute this software and its | |
| 19 | * documentation is hereby granted, provided that both the copyright | |
| 20 | * notice and this permission notice appear in all copies of the | |
| 21 | * software, derivative works or modified versions, and any portions | |
| 22 | * thereof, and that both notices appear in supporting documentation. | |
| 23 | * | |
| 24 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" | |
| 25 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR | |
| 26 | * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. | |
| 27 | * | |
| 28 | * Carnegie Mellon requests users of this software to return to | |
| 29 | * | |
| 30 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU | |
| 31 | * School of Computer Science | |
| 32 | * Carnegie Mellon University | |
| 33 | * Pittsburgh PA 15213-3890 | |
| 34 | * | |
| 35 | * any improvements or extensions that they make and grant Carnegie the | |
| 36 | * rights to redistribute these changes. | |
| 37 | */ | |
| 38 | ||
| 39 | /* | |
| 40 | * Dynamic memory allocator | |
| 41 | */ | |
| 42 | struct fl { | |
| 43 | struct fl *next; | |
| 44 | unsigned size; | |
| 45 | } *freelist = (struct fl *)0; | |
| 46 | ||
| 47 | extern char end[]; | |
| 48 | static char *top = end; | |
| 49 | ||
| 50 | void * | |
| 51 | alloc(size) | |
| 52 | unsigned size; | |
| 53 | { | |
| 54 | register struct fl *f = freelist, **prev; | |
| 55 | ||
| 56 | prev = &freelist; | |
| 57 | while (f && f->size < size) { | |
| 58 | prev = &f->next; | |
| 59 | f = f->next; | |
| 60 | } | |
| 61 | if (f == (struct fl *)0) { | |
| 62 | f = (struct fl *)top; | |
| 63 | top += (size + 3) & ~3; | |
| 64 | } else | |
| 65 | *prev = f->next; | |
| 66 | return ((void *)f); | |
| 67 | } | |
| 68 | ||
| 69 | void | |
| 70 | free(ptr, size) | |
| 71 | void *ptr; | |
| 72 | unsigned size; | |
| 73 | { | |
| 74 | register struct fl *f = (struct fl *)ptr; | |
| 75 | ||
| 76 | f->size = (size + 3) & ~3; | |
| 77 | f->next = freelist; | |
| 78 | freelist = f; | |
| 79 | } |