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root/radiance/ray/src/rt/ambient.c
Revision: 2.49
Committed: Thu May 15 05:13:35 2003 UTC (20 years, 11 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.48: +3 -3 lines
Log Message:
Eliminated -DBIGMEM define, since we always used it in makeall

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id$";
3 #endif
4 /*
5 * ambient.c - routines dealing with ambient (inter-reflected) component.
6 *
7 * Declarations of external symbols in ambient.h
8 */
9
10 #include "copyright.h"
11
12 #include "ray.h"
13
14 #include "otypes.h"
15
16 #include "ambient.h"
17
18 #include "random.h"
19
20 #ifndef OCTSCALE
21 #define OCTSCALE 1.0 /* ceil((valid rad.)/(cube size)) */
22 #endif
23
24 extern char *shm_boundary; /* memory sharing boundary */
25
26 #define MAXASET 511 /* maximum number of elements in ambient set */
27 OBJECT ambset[MAXASET+1]={0}; /* ambient include/exclude set */
28
29 double maxarad; /* maximum ambient radius */
30 double minarad; /* minimum ambient radius */
31
32 static AMBTREE atrunk; /* our ambient trunk node */
33
34 static FILE *ambfp = NULL; /* ambient file pointer */
35 static int nunflshed = 0; /* number of unflushed ambient values */
36
37 #ifndef SORT_THRESH
38 #ifdef SMLMEM
39 #define SORT_THRESH ((3L<<20)/sizeof(AMBVAL))
40 #else
41 #define SORT_THRESH ((9L<<20)/sizeof(AMBVAL))
42 #endif
43 #endif
44 #ifndef SORT_INTVL
45 #define SORT_INTVL (SORT_THRESH<<1)
46 #endif
47 #ifndef MAX_SORT_INTVL
48 #define MAX_SORT_INTVL (SORT_INTVL<<6)
49 #endif
50
51 static double avsum = 0.; /* computed ambient value sum (log) */
52 static unsigned int navsum = 0; /* number of values in avsum */
53 static unsigned int nambvals = 0; /* total number of indirect values */
54 static unsigned int nambshare = 0; /* number of values from file */
55 static unsigned long ambclock = 0; /* ambient access clock */
56 static unsigned long lastsort = 0; /* time of last value sort */
57 static long sortintvl = SORT_INTVL; /* time until next sort */
58 static FILE *ambinp = NULL; /* auxiliary file for input */
59 static long lastpos = -1; /* last flush position */
60
61 #define MAXACLOCK (1L<<30) /* clock turnover value */
62 /*
63 * Track access times unless we are sharing ambient values
64 * through memory on a multiprocessor, when we want to avoid
65 * claiming our own memory (copy on write). Go ahead anyway
66 * if more than two thirds of our values are unshared.
67 * Compile with -Dtracktime=0 to turn this code off.
68 */
69 #ifndef tracktime
70 #define tracktime (shm_boundary == NULL || nambvals > 3*nambshare)
71 #endif
72
73 #define AMBFLUSH (BUFSIZ/AMBVALSIZ)
74
75 #define newambval() (AMBVAL *)malloc(sizeof(AMBVAL))
76 #define freeav(av) free((void *)av);
77
78 static void initambfile(), avsave(), avinsert(), sortambvals(), unloadatree();
79 static int avlmemi();
80 static AMBVAL *avstore();
81 #ifdef F_SETLKW
82 static void aflock();
83 #endif
84
85
86 void
87 setambres(ar) /* set ambient resolution */
88 int ar;
89 {
90 ambres = ar < 0 ? 0 : ar; /* may be done already */
91 /* set min & max radii */
92 if (ar <= 0) {
93 minarad = 0;
94 maxarad = thescene.cusize / 2.0;
95 } else {
96 minarad = thescene.cusize / ar;
97 maxarad = 64 * minarad; /* heuristic */
98 if (maxarad > thescene.cusize / 2.0)
99 maxarad = thescene.cusize / 2.0;
100 }
101 if (minarad <= FTINY)
102 minarad = 10*FTINY;
103 if (maxarad <= minarad)
104 maxarad = 64 * minarad;
105 }
106
107
108 void
109 setambacc(newa) /* set ambient accuracy */
110 double newa;
111 {
112 double ambdiff;
113
114 if (newa < 0.0)
115 newa = 0.0;
116 ambdiff = fabs(newa - ambacc);
117 if (ambdiff >= .01 && (ambacc = newa) > FTINY && nambvals > 0)
118 sortambvals(1); /* rebuild tree */
119 }
120
121
122 void
123 setambient() /* initialize calculation */
124 {
125 int readonly = 0;
126 long pos, flen;
127 AMBVAL amb;
128 /* make sure we're fresh */
129 ambdone();
130 /* init ambient limits */
131 setambres(ambres);
132 setambacc(ambacc);
133 if (ambfile == NULL || !ambfile[0])
134 return;
135 if (ambacc <= FTINY) {
136 sprintf(errmsg, "zero ambient accuracy so \"%s\" not opened",
137 ambfile);
138 error(WARNING, errmsg);
139 return;
140 }
141 /* open ambient file */
142 if ((ambfp = fopen(ambfile, "r+")) == NULL)
143 readonly = (ambfp = fopen(ambfile, "r")) != NULL;
144 if (ambfp != NULL) {
145 initambfile(0); /* file exists */
146 pos = ftell(ambfp);
147 while (readambval(&amb, ambfp))
148 avinsert(avstore(&amb));
149 nambshare = nambvals; /* share loaded values */
150 if (readonly) {
151 sprintf(errmsg,
152 "loaded %u values from read-only ambient file",
153 nambvals);
154 error(WARNING, errmsg);
155 fclose(ambfp); /* close file so no writes */
156 ambfp = NULL;
157 return; /* avoid ambsync() */
158 }
159 /* align file pointer */
160 pos += (long)nambvals*AMBVALSIZ;
161 flen = lseek(fileno(ambfp), (off_t)0L, 2);
162 if (flen != pos) {
163 sprintf(errmsg,
164 "ignoring last %ld values in ambient file (corrupted)",
165 (flen - pos)/AMBVALSIZ);
166 error(WARNING, errmsg);
167 fseek(ambfp, pos, 0);
168 ftruncate(fileno(ambfp), (off_t)pos);
169 }
170 } else if ((ambfp = fopen(ambfile, "w+")) != NULL) {
171 initambfile(1); /* else create new file */
172 } else {
173 sprintf(errmsg, "cannot open ambient file \"%s\"", ambfile);
174 error(SYSTEM, errmsg);
175 }
176 nunflshed++; /* lie */
177 ambsync();
178 }
179
180
181 void
182 ambdone() /* close ambient file and free memory */
183 {
184 if (ambfp != NULL) { /* close ambient file */
185 ambsync();
186 fclose(ambfp);
187 ambfp = NULL;
188 if (ambinp != NULL) {
189 fclose(ambinp);
190 ambinp = NULL;
191 }
192 lastpos = -1;
193 }
194 /* free ambient tree */
195 unloadatree(&atrunk, free);
196 /* reset state variables */
197 avsum = 0.;
198 navsum = 0;
199 nambvals = 0;
200 nambshare = 0;
201 ambclock = 0;
202 lastsort = 0;
203 sortintvl = SORT_INTVL;
204 }
205
206
207 void
208 ambnotify(obj) /* record new modifier */
209 OBJECT obj;
210 {
211 static int hitlimit = 0;
212 register OBJREC *o;
213 register char **amblp;
214
215 if (obj == OVOID) { /* starting over */
216 ambset[0] = 0;
217 hitlimit = 0;
218 return;
219 }
220 o = objptr(obj);
221 if (hitlimit || !ismodifier(o->otype))
222 return;
223 for (amblp = amblist; *amblp != NULL; amblp++)
224 if (!strcmp(o->oname, *amblp)) {
225 if (ambset[0] >= MAXASET) {
226 error(WARNING, "too many modifiers in ambient list");
227 hitlimit++;
228 return; /* should this be fatal? */
229 }
230 insertelem(ambset, obj);
231 return;
232 }
233 }
234
235
236 void
237 ambient(acol, r, nrm) /* compute ambient component for ray */
238 COLOR acol;
239 register RAY *r;
240 FVECT nrm;
241 {
242 static int rdepth = 0; /* ambient recursion */
243 double d, l;
244
245 if (ambdiv <= 0) /* no ambient calculation */
246 goto dumbamb;
247 /* check number of bounces */
248 if (rdepth >= ambounce)
249 goto dumbamb;
250 /* check ambient list */
251 if (ambincl != -1 && r->ro != NULL &&
252 ambincl != inset(ambset, r->ro->omod))
253 goto dumbamb;
254
255 if (ambacc <= FTINY) { /* no ambient storage */
256 rdepth++;
257 d = doambient(acol, r, r->rweight, NULL, NULL);
258 rdepth--;
259 if (d <= FTINY)
260 goto dumbamb;
261 return;
262 }
263
264 if (tracktime) /* sort to minimize thrashing */
265 sortambvals(0);
266 /* get ambient value */
267 setcolor(acol, 0.0, 0.0, 0.0);
268 d = sumambient(acol, r, nrm, rdepth,
269 &atrunk, thescene.cuorg, thescene.cusize);
270 if (d > FTINY) {
271 scalecolor(acol, 1.0/d);
272 return;
273 }
274 rdepth++; /* need to cache new value */
275 d = makeambient(acol, r, nrm, rdepth-1);
276 rdepth--;
277 if (d > FTINY)
278 return;
279 dumbamb: /* return global value */
280 copycolor(acol, ambval);
281 if (ambvwt <= 0 | navsum == 0)
282 return;
283 l = bright(ambval); /* average in computations */
284 if (l > FTINY) {
285 d = (log(l)*(double)ambvwt + avsum) /
286 (double)(ambvwt + navsum);
287 d = exp(d) / l;
288 scalecolor(acol, d); /* apply color of ambval */
289 } else {
290 d = exp( avsum / (double)navsum );
291 setcolor(acol, d, d, d); /* neutral color */
292 }
293 }
294
295
296 double
297 sumambient(acol, r, rn, al, at, c0, s) /* get interpolated ambient value */
298 COLOR acol;
299 register RAY *r;
300 FVECT rn;
301 int al;
302 AMBTREE *at;
303 FVECT c0;
304 double s;
305 {
306 double d, e1, e2, wt, wsum;
307 COLOR ct;
308 FVECT ck0;
309 int i;
310 register int j;
311 register AMBVAL *av;
312
313 wsum = 0.0;
314 /* do this node */
315 for (av = at->alist; av != NULL; av = av->next) {
316 double rn_dot = -2.0;
317 if (tracktime)
318 av->latick = ambclock;
319 /*
320 * Ambient level test.
321 */
322 if (av->lvl > al) /* list sorted, so this works */
323 break;
324 if (av->weight < r->rweight-FTINY)
325 continue;
326 /*
327 * Ambient radius test.
328 */
329 d = av->pos[0] - r->rop[0];
330 e1 = d * d;
331 d = av->pos[1] - r->rop[1];
332 e1 += d * d;
333 d = av->pos[2] - r->rop[2];
334 e1 += d * d;
335 e1 /= av->rad * av->rad;
336 if (e1 > ambacc*ambacc*1.21)
337 continue;
338 /*
339 * Direction test using closest normal.
340 */
341 d = DOT(av->dir, r->ron);
342 if (rn != r->ron) {
343 rn_dot = DOT(av->dir, rn);
344 if (rn_dot > 1.0-FTINY)
345 rn_dot = 1.0-FTINY;
346 if (rn_dot >= d-FTINY) {
347 d = rn_dot;
348 rn_dot = -2.0;
349 }
350 }
351 e2 = (1.0 - d) * r->rweight;
352 if (e2 < 0.0) e2 = 0.0;
353 if (e1 + e2 > ambacc*ambacc*1.21)
354 continue;
355 /*
356 * Ray behind test.
357 */
358 d = 0.0;
359 for (j = 0; j < 3; j++)
360 d += (r->rop[j] - av->pos[j]) *
361 (av->dir[j] + r->ron[j]);
362 if (d*0.5 < -minarad*ambacc-.001)
363 continue;
364 /*
365 * Jittering final test reduces image artifacts.
366 */
367 e1 = sqrt(e1);
368 e2 = sqrt(e2);
369 wt = e1 + e2;
370 if (wt > ambacc*(.9+.2*urand(9015+samplendx)))
371 continue;
372 /*
373 * Recompute directional error using perturbed normal
374 */
375 if (rn_dot > 0.0) {
376 e2 = sqrt((1.0 - rn_dot)*r->rweight);
377 wt = e1 + e2;
378 }
379 if (wt <= 1e-3)
380 wt = 1e3;
381 else
382 wt = 1.0 / wt;
383 wsum += wt;
384 extambient(ct, av, r->rop, rn);
385 scalecolor(ct, wt);
386 addcolor(acol, ct);
387 }
388 if (at->kid == NULL)
389 return(wsum);
390 /* do children */
391 s *= 0.5;
392 for (i = 0; i < 8; i++) {
393 for (j = 0; j < 3; j++) {
394 ck0[j] = c0[j];
395 if (1<<j & i)
396 ck0[j] += s;
397 if (r->rop[j] < ck0[j] - OCTSCALE*s)
398 break;
399 if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
400 break;
401 }
402 if (j == 3)
403 wsum += sumambient(acol, r, rn, al, at->kid+i, ck0, s);
404 }
405 return(wsum);
406 }
407
408
409 double
410 makeambient(acol, r, rn, al) /* make a new ambient value */
411 COLOR acol;
412 register RAY *r;
413 FVECT rn;
414 int al;
415 {
416 AMBVAL amb;
417 FVECT gp, gd;
418 /* compute weight */
419 amb.weight = pow(AVGREFL, (double)al);
420 if (r->rweight < 0.1*amb.weight) /* heuristic */
421 amb.weight = r->rweight;
422 /* compute ambient */
423 amb.rad = doambient(acol, r, amb.weight, gp, gd);
424 if (amb.rad <= FTINY)
425 return(0.0);
426 /* store it */
427 VCOPY(amb.pos, r->rop);
428 VCOPY(amb.dir, r->ron);
429 amb.lvl = al;
430 copycolor(amb.val, acol);
431 VCOPY(amb.gpos, gp);
432 VCOPY(amb.gdir, gd);
433 /* insert into tree */
434 avsave(&amb); /* and save to file */
435 if (rn != r->ron)
436 extambient(acol, &amb, r->rop, rn); /* texture */
437 return(amb.rad);
438 }
439
440
441 void
442 extambient(cr, ap, pv, nv) /* extrapolate value at pv, nv */
443 COLOR cr;
444 register AMBVAL *ap;
445 FVECT pv, nv;
446 {
447 FVECT v1;
448 register int i;
449 double d;
450
451 d = 1.0; /* zeroeth order */
452 /* gradient due to translation */
453 for (i = 0; i < 3; i++)
454 d += ap->gpos[i]*(pv[i]-ap->pos[i]);
455 /* gradient due to rotation */
456 VCROSS(v1, ap->dir, nv);
457 d += DOT(ap->gdir, v1);
458 if (d <= 0.0) {
459 setcolor(cr, 0.0, 0.0, 0.0);
460 return;
461 }
462 copycolor(cr, ap->val);
463 scalecolor(cr, d);
464 }
465
466
467 static void
468 initambfile(creat) /* initialize ambient file */
469 int creat;
470 {
471 extern char *progname, *octname;
472 static char *mybuf = NULL;
473
474 #ifdef F_SETLKW
475 aflock(creat ? F_WRLCK : F_RDLCK);
476 #endif
477 #ifdef MSDOS
478 setmode(fileno(ambfp), O_BINARY);
479 #endif
480 if (mybuf == NULL)
481 mybuf = (char *)bmalloc(BUFSIZ+8);
482 setbuf(ambfp, mybuf);
483 if (creat) { /* new file */
484 newheader("RADIANCE", ambfp);
485 fprintf(ambfp, "%s -av %g %g %g -aw %d -ab %d -aa %g ",
486 progname, colval(ambval,RED),
487 colval(ambval,GRN), colval(ambval,BLU),
488 ambvwt, ambounce, ambacc);
489 fprintf(ambfp, "-ad %d -as %d -ar %d ",
490 ambdiv, ambssamp, ambres);
491 if (octname != NULL)
492 printargs(1, &octname, ambfp);
493 else
494 fputc('\n', ambfp);
495 fprintf(ambfp, "SOFTWARE= %s\n", VersionID);
496 fputnow(ambfp);
497 fputformat(AMBFMT, ambfp);
498 putc('\n', ambfp);
499 putambmagic(ambfp);
500 } else if (checkheader(ambfp, AMBFMT, NULL) < 0 || !hasambmagic(ambfp))
501 error(USER, "bad ambient file");
502 }
503
504
505 static void
506 avsave(av) /* insert and save an ambient value */
507 AMBVAL *av;
508 {
509 avinsert(avstore(av));
510 if (ambfp == NULL)
511 return;
512 if (writambval(av, ambfp) < 0)
513 goto writerr;
514 if (++nunflshed >= AMBFLUSH)
515 if (ambsync() == EOF)
516 goto writerr;
517 return;
518 writerr:
519 error(SYSTEM, "error writing to ambient file");
520 }
521
522
523 static AMBVAL *
524 avstore(aval) /* allocate memory and store aval */
525 register AMBVAL *aval;
526 {
527 register AMBVAL *av;
528 double d;
529
530 if ((av = newambval()) == NULL)
531 error(SYSTEM, "out of memory in avstore");
532 copystruct(av, aval);
533 av->latick = ambclock;
534 av->next = NULL;
535 nambvals++;
536 d = bright(av->val);
537 if (d > FTINY) { /* add to log sum for averaging */
538 avsum += log(d);
539 navsum++;
540 }
541 return(av);
542 }
543
544
545 #define ATALLOCSZ 512 /* #/8 trees to allocate at once */
546
547 static AMBTREE *atfreelist = NULL; /* free ambient tree structures */
548
549
550 static AMBTREE *
551 newambtree() /* allocate 8 ambient tree structs */
552 {
553 register AMBTREE *atp, *upperlim;
554
555 if (atfreelist == NULL) { /* get more nodes */
556 atfreelist = (AMBTREE *)malloc(ATALLOCSZ*8*sizeof(AMBTREE));
557 if (atfreelist == NULL)
558 return(NULL);
559 /* link new free list */
560 upperlim = atfreelist + 8*(ATALLOCSZ-1);
561 for (atp = atfreelist; atp < upperlim; atp += 8)
562 atp->kid = atp + 8;
563 atp->kid = NULL;
564 }
565 atp = atfreelist;
566 atfreelist = atp->kid;
567 bzero((char *)atp, 8*sizeof(AMBTREE));
568 return(atp);
569 }
570
571
572 static void
573 freeambtree(atp) /* free 8 ambient tree structs */
574 AMBTREE *atp;
575 {
576 atp->kid = atfreelist;
577 atfreelist = atp;
578 }
579
580
581 static void
582 avinsert(av) /* insert ambient value in our tree */
583 register AMBVAL *av;
584 {
585 register AMBTREE *at;
586 register AMBVAL *ap;
587 AMBVAL avh;
588 FVECT ck0;
589 double s;
590 int branch;
591 register int i;
592
593 if (av->rad <= FTINY)
594 error(CONSISTENCY, "zero ambient radius in avinsert");
595 at = &atrunk;
596 VCOPY(ck0, thescene.cuorg);
597 s = thescene.cusize;
598 while (s*(OCTSCALE/2) > av->rad*ambacc) {
599 if (at->kid == NULL)
600 if ((at->kid = newambtree()) == NULL)
601 error(SYSTEM, "out of memory in avinsert");
602 s *= 0.5;
603 branch = 0;
604 for (i = 0; i < 3; i++)
605 if (av->pos[i] > ck0[i] + s) {
606 ck0[i] += s;
607 branch |= 1 << i;
608 }
609 at = at->kid + branch;
610 }
611 avh.next = at->alist; /* order by increasing level */
612 for (ap = &avh; ap->next != NULL; ap = ap->next)
613 if (ap->next->lvl >= av->lvl)
614 break;
615 av->next = ap->next;
616 ap->next = av;
617 at->alist = avh.next;
618 }
619
620
621 static void
622 unloadatree(at, f) /* unload an ambient value tree */
623 register AMBTREE *at;
624 void (*f)();
625 {
626 register AMBVAL *av;
627 register int i;
628 /* transfer values at this node */
629 for (av = at->alist; av != NULL; av = at->alist) {
630 at->alist = av->next;
631 (*f)(av);
632 }
633 if (at->kid == NULL)
634 return;
635 for (i = 0; i < 8; i++) /* transfer and free children */
636 unloadatree(at->kid+i, f);
637 freeambtree(at->kid);
638 at->kid = NULL;
639 }
640
641
642 static struct avl {
643 AMBVAL *p;
644 unsigned long t;
645 } *avlist1; /* ambient value list with ticks */
646 static AMBVAL **avlist2; /* memory positions for sorting */
647 static int i_avlist; /* index for lists */
648
649
650 static int
651 av2list(av)
652 register AMBVAL *av;
653 {
654 #ifdef DEBUG
655 if (i_avlist >= nambvals)
656 error(CONSISTENCY, "too many ambient values in av2list1");
657 #endif
658 avlist1[i_avlist].p = avlist2[i_avlist] = av;
659 avlist1[i_avlist++].t = av->latick;
660 }
661
662
663 static int
664 alatcmp(av1, av2) /* compare ambient values for MRA */
665 struct avl *av1, *av2;
666 {
667 register long lc = av2->t - av1->t;
668 return(lc<0 ? -1 : lc>0 ? 1 : 0);
669 }
670
671
672 /* GW NOTE 2002/10/3:
673 * I used to compare AMBVAL pointers, but found that this was the
674 * cause of a serious consistency error with gcc, since the optimizer
675 * uses some dangerous trick in pointer subtraction that
676 * assumes pointers differ by exact struct size increments.
677 */
678 static int
679 aposcmp(avp1, avp2) /* compare ambient value positions */
680 const void *avp1, *avp2;
681 {
682 register long diff = *(char * const *)avp1 - *(char * const *)avp2;
683 if (diff < 0)
684 return(-1);
685 return(diff > 0);
686 }
687
688 #if 1
689 static int
690 avlmemi(avaddr) /* find list position from address */
691 AMBVAL *avaddr;
692 {
693 register AMBVAL **avlpp;
694
695 avlpp = (AMBVAL **)bsearch((char *)&avaddr, (char *)avlist2,
696 nambvals, sizeof(AMBVAL *), aposcmp);
697 if (avlpp == NULL)
698 error(CONSISTENCY, "address not found in avlmemi");
699 return(avlpp - avlist2);
700 }
701 #else
702 #define avlmemi(avaddr) ((AMBVAL **)bsearch((char *)&avaddr,(char *)avlist2, \
703 nambvals,sizeof(AMBVAL *),aposcmp) - avlist2)
704 #endif
705
706
707 static void
708 sortambvals(always) /* resort ambient values */
709 int always;
710 {
711 AMBTREE oldatrunk;
712 AMBVAL tav, *tap, *pnext;
713 register int i, j;
714 /* see if it's time yet */
715 if (!always && (ambclock++ < lastsort+sortintvl ||
716 nambvals < SORT_THRESH))
717 return;
718 /*
719 * The idea here is to minimize memory thrashing
720 * in VM systems by improving reference locality.
721 * We do this by periodically sorting our stored ambient
722 * values in memory in order of most recently to least
723 * recently accessed. This ordering was chosen so that new
724 * ambient values (which tend to be less important) go into
725 * higher memory with the infrequently accessed values.
726 * Since we expect our values to need sorting less
727 * frequently as the process continues, we double our
728 * waiting interval after each call.
729 * This routine is also called by setambacc() with
730 * the "always" parameter set to 1 so that the ambient
731 * tree will be rebuilt with the new accuracy parameter.
732 */
733 if (tracktime) { /* allocate pointer arrays to sort */
734 avlist2 = (AMBVAL **)malloc(nambvals*sizeof(AMBVAL *));
735 avlist1 = (struct avl *)malloc(nambvals*sizeof(struct avl));
736 } else {
737 avlist2 = NULL;
738 avlist1 = NULL;
739 }
740 if (avlist1 == NULL) { /* no time tracking -- rebuild tree? */
741 if (avlist2 != NULL)
742 free((void *)avlist2);
743 if (always) { /* rebuild without sorting */
744 copystruct(&oldatrunk, &atrunk);
745 atrunk.alist = NULL;
746 atrunk.kid = NULL;
747 unloadatree(&oldatrunk, avinsert);
748 }
749 } else { /* sort memory by last access time */
750 /*
751 * Sorting memory is tricky because it isn't contiguous.
752 * We have to sort an array of pointers by MRA and also
753 * by memory position. We then copy values in "loops"
754 * to minimize memory hits. Nevertheless, we will visit
755 * everyone at least twice, and this is an expensive process
756 * when we're thrashing, which is when we need to do it.
757 */
758 #ifdef DEBUG
759 sprintf(errmsg, "sorting %u ambient values at ambclock=%lu...",
760 nambvals, ambclock);
761 eputs(errmsg);
762 #endif
763 i_avlist = 0;
764 unloadatree(&atrunk, av2list); /* empty current tree */
765 #ifdef DEBUG
766 if (i_avlist < nambvals)
767 error(CONSISTENCY, "missing ambient values in sortambvals");
768 #endif
769 qsort((char *)avlist1, nambvals, sizeof(struct avl), alatcmp);
770 qsort((char *)avlist2, nambvals, sizeof(AMBVAL *), aposcmp);
771 for (i = 0; i < nambvals; i++) {
772 if (avlist1[i].p == NULL)
773 continue;
774 tap = avlist2[i];
775 copystruct(&tav, tap);
776 for (j = i; (pnext = avlist1[j].p) != tap;
777 j = avlmemi(pnext)) {
778 copystruct(avlist2[j], pnext);
779 avinsert(avlist2[j]);
780 avlist1[j].p = NULL;
781 }
782 copystruct(avlist2[j], &tav);
783 avinsert(avlist2[j]);
784 avlist1[j].p = NULL;
785 }
786 free((void *)avlist1);
787 free((void *)avlist2);
788 /* compute new sort interval */
789 sortintvl = ambclock - lastsort;
790 if (sortintvl >= MAX_SORT_INTVL/2)
791 sortintvl = MAX_SORT_INTVL;
792 else
793 sortintvl <<= 1; /* wait twice as long next */
794 #ifdef DEBUG
795 eputs("done\n");
796 #endif
797 }
798 if (ambclock >= MAXACLOCK)
799 ambclock = MAXACLOCK/2;
800 lastsort = ambclock;
801 }
802
803
804 #ifdef F_SETLKW
805
806 static void
807 aflock(typ) /* lock/unlock ambient file */
808 int typ;
809 {
810 static struct flock fls; /* static so initialized to zeroes */
811
812 fls.l_type = typ;
813 if (fcntl(fileno(ambfp), F_SETLKW, &fls) < 0)
814 error(SYSTEM, "cannot (un)lock ambient file");
815 }
816
817
818 int
819 ambsync() /* synchronize ambient file */
820 {
821 long flen;
822 AMBVAL avs;
823 register int n;
824
825 if (nunflshed == 0)
826 return(0);
827 if (lastpos < 0) /* initializing (locked in initambfile) */
828 goto syncend;
829 /* gain exclusive access */
830 aflock(F_WRLCK);
831 /* see if file has grown */
832 if ((flen = lseek(fileno(ambfp), (off_t)0L, 2)) < 0)
833 goto seekerr;
834 if (n = flen - lastpos) { /* file has grown */
835 if (ambinp == NULL) { /* use duplicate filedes */
836 ambinp = fdopen(dup(fileno(ambfp)), "r");
837 if (ambinp == NULL)
838 error(SYSTEM, "fdopen failed in ambsync");
839 }
840 if (fseek(ambinp, lastpos, 0) < 0)
841 goto seekerr;
842 while (n >= AMBVALSIZ) { /* load contributed values */
843 if (!readambval(&avs, ambinp)) {
844 sprintf(errmsg,
845 "ambient file \"%s\" corrupted near character %ld",
846 ambfile, flen - n);
847 error(WARNING, errmsg);
848 break;
849 }
850 avinsert(avstore(&avs));
851 n -= AMBVALSIZ;
852 }
853 /*** seek always as safety measure
854 if (n) ***/ /* alignment */
855 if (lseek(fileno(ambfp), (off_t)(flen-n), 0) < 0)
856 goto seekerr;
857 }
858 #ifdef DEBUG
859 if (ambfp->_ptr - ambfp->_base != nunflshed*AMBVALSIZ) {
860 sprintf(errmsg, "ambient file buffer at %d rather than %d",
861 ambfp->_ptr - ambfp->_base,
862 nunflshed*AMBVALSIZ);
863 error(CONSISTENCY, errmsg);
864 }
865 #endif
866 syncend:
867 n = fflush(ambfp); /* calls write() at last */
868 if ((lastpos = lseek(fileno(ambfp), (off_t)0L, 1)) < 0)
869 goto seekerr;
870 aflock(F_UNLCK); /* release file */
871 nunflshed = 0;
872 return(n);
873 seekerr:
874 error(SYSTEM, "seek failed in ambsync");
875 }
876
877 #else
878
879 int
880 ambsync() /* flush ambient file */
881 {
882 if (nunflshed == 0)
883 return(0);
884 nunflshed = 0;
885 return(fflush(ambfp));
886 }
887
888 #endif