* Copyright (c) 1992 William F. Jolitz, TeleMuse
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* 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
static char rcsid
[] = "$Header: /usr/bill/working/sys/kern/RCS/subr_rlist.c,v 1.2 92/01/21 21:29:31 william Exp $";
* 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
; {
/* if nothing here, insert (tail of list) */
*rlp
= (struct rlist
*)malloc(sizeof(**rlp
), M_TEMP
, M_NOWAIT
);
(*rlp
)->rl_start
= start
;
/* if new region overlaps something currently present, panic */
if (start
>= (*rlp
)->rl_start
&& start
<= (*rlp
)->rl_end
)
panic("overlapping rlist_free: freed twice?");
if (end
>= (*rlp
)->rl_start
&& end
<= (*rlp
)->rl_end
)
panic("overlapping rlist_free: freed twice?");
/* are we adjacent to this element? (in front) */
if (end
+1 == (*rlp
)->rl_start
) {
(*rlp
)->rl_start
= start
;
/* are we before this element? */
if (end
< (*rlp
)->rl_start
) {
register struct rlist
*nlp
;
nlp
= (struct rlist
*)malloc(sizeof(*nlp
), M_TEMP
, M_NOWAIT
);
/* are we adjacent to this element? (at tail) */
if ((*rlp
)->rl_end
+ 1 == start
) {
/* are we after this element */
if (start
> (*rlp
)->rl_end
) {
rlp
= &((*rlp
)->rl_next
);
panic("rlist_free: can't happen");
/* can we coalesce list now that we've filled a void? */
register struct rlist
*lp
, *lpn
;
for (lp
= head
; lp
->rl_next
;) {
if (lp
->rl_end
+ 1 == lpn
->rl_start
) {
lp
->rl_end
= lpn
->rl_end
;
lp
->rl_next
= lpn
->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
= *rlp
, *olp
= 0;
/* walk list, allocating first thing that's big enough (first fit) */
for (; *rlp
; rlp
= &((*rlp
)->rl_next
))
if(size
<= (*rlp
)->rl_start
- (*rlp
)->rl_end
+ 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
) {
/* nothing in list that's big enough */
* Finished with this resource list, reclaim all space and
* mark it as being empty.