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/*
* 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);
}
}
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