+/*
+ * Copyright (c) 1992 William F. Jolitz, TeleMuse
+ * 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. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This software is a component of "386BSD" developed by
+ William F. Jolitz, TeleMuse.
+ * 4. Neither the name of the developer nor the name "386BSD"
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ
+ * AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS
+ * SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT.
+ * THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT
+ * NOT MAKE USE THIS WORK.
+ *
+ * FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED
+ * BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN
+ * REFERENCES SUCH AS THE "PORTING UNIX TO THE 386" SERIES
+ * (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING
+ * JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND
+ * LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE
+ * ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS
+ * OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``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 DEVELOPER 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.
+ *
+ */
+static char rcsid[] = "$Header: /usr/bill/working/sys/kern/RCS/subr_rlist.c,v 1.2 92/01/21 21:29:31 william Exp $";
+
+#include "sys/param.h"
+#include "sys/cdefs.h"
+#include "sys/malloc.h"
+#include "rlist.h"
+
+/*
+ * Resource lists.
+ */
+
+/*
+ * Add space to a resource list. Used to either
+ * initialize a list or return free space to it.
+ */
+rlist_free (rlp, start, end)
+register struct rlist **rlp; unsigned start, end; {
+ struct rlist *head;
+
+ head = *rlp;
+
+loop:
+ /* if nothing here, insert (tail of list) */
+ if (*rlp == 0) {
+ *rlp = (struct rlist *)malloc(sizeof(**rlp), M_TEMP, M_NOWAIT);
+ (*rlp)->rl_start = start;
+ (*rlp)->rl_end = end;
+ (*rlp)->rl_next = 0;
+ return;
+ }
+
+ /* if new region overlaps something currently present, panic */
+ if (start >= (*rlp)->rl_start && start <= (*rlp)->rl_end) {
+ printf("Frag %d:%d, ent %d:%d ", start, end,
+ (*rlp)->rl_start, (*rlp)->rl_end);
+ panic("overlapping front rlist_free: freed twice?");
+ }
+ if (end >= (*rlp)->rl_start && end <= (*rlp)->rl_end) {
+ printf("Frag %d:%d, ent %d:%d ", start, end,
+ (*rlp)->rl_start, (*rlp)->rl_end);
+ panic("overlapping tail rlist_free: freed twice?");
+ }
+
+ /* are we adjacent to this element? (in front) */
+ if (end+1 == (*rlp)->rl_start) {
+ /* coalesce */
+ (*rlp)->rl_start = start;
+ goto scan;
+ }
+
+ /* are we before this element? */
+ if (end < (*rlp)->rl_start) {
+ register struct rlist *nlp;
+
+ nlp = (struct rlist *)malloc(sizeof(*nlp), M_TEMP, M_NOWAIT);
+ nlp->rl_start = start;
+ nlp->rl_end = end;
+ nlp->rl_next = *rlp;
+ *rlp = nlp;
+ return;
+ }
+
+ /* are we adjacent to this element? (at tail) */
+ if ((*rlp)->rl_end + 1 == start) {
+ /* coalesce */
+ (*rlp)->rl_end = end;
+ goto scan;
+ }
+
+ /* are we after this element */
+ if (start > (*rlp)->rl_end) {
+ rlp = &((*rlp)->rl_next);
+ goto loop;
+ } else
+ panic("rlist_free: can't happen");
+
+scan:
+ /* can we coalesce list now that we've filled a void? */
+ {
+ register struct rlist *lp, *lpn;
+
+ for (lp = head; lp->rl_next ;) {
+ lpn = lp->rl_next;
+
+ /* coalesce ? */
+ if (lp->rl_end + 1 == lpn->rl_start) {
+ lp->rl_end = lpn->rl_end;
+ lp->rl_next = lpn->rl_next;
+ free(lpn, M_TEMP);
+ } else
+ lp = lp->rl_next;
+ }
+ }
+}
+
+/*
+ * Obtain a region of desired size from a resource list.
+ * If nothing available of that size, return 0. Otherwise,
+ * return a value of 1 and set resource start location with
+ * "*loc". (Note: loc can be zero if we don't wish the value)
+ */
+int rlist_alloc (rlp, size, loc)
+struct rlist **rlp; unsigned size, *loc; {
+ register struct rlist *lp;
+
+
+ /* walk list, allocating first thing that's big enough (first fit) */
+ for (; *rlp; rlp = &((*rlp)->rl_next))
+ if(size <= (*rlp)->rl_end - (*rlp)->rl_start + 1) {
+
+ /* hand it to the caller */
+ if (loc) *loc = (*rlp)->rl_start;
+ (*rlp)->rl_start += size;
+
+ /* did we eat this element entirely? */
+ if ((*rlp)->rl_start > (*rlp)->rl_end) {
+ lp = (*rlp)->rl_next;
+ free (*rlp, M_TEMP);
+ *rlp = lp;
+ }
+
+ return (1);
+ }
+
+ /* nothing in list that's big enough */
+ return (0);
+}
+
+/*
+ * Finished with this resource list, reclaim all space and
+ * mark it as being empty.
+ */
+rlist_destroy (rlp)
+struct rlist **rlp; {
+ struct rlist *lp, *nlp;
+
+ lp = *rlp;
+ *rlp = 0;
+ for (; lp; lp = nlp) {
+ nlp = lp->rl_next;
+ free (lp, M_TEMP);
+ }
+}
projects / unix-history / commitdiff