--- ray/src/rt/ambient.c	2016/04/24 16:21:32	2.102
+++ ray/src/rt/ambient.c	2023/01/27 19:57:08	2.116
@@ -1,4 +1,4 @@
-static const char	RCSid[] = "$Id: ambient.c,v 2.102 2016/04/24 16:21:32 greg Exp $";
+static const char	RCSid[] = "$Id: ambient.c,v 2.116 2023/01/27 19:57:08 greg Exp $";
 /*
  *  ambient.c - routines dealing with ambient (inter-reflected) component.
  *
@@ -12,6 +12,7 @@ static const char	RCSid[] = "$Id: ambient.c,v 2.102 20
 #include  "platform.h"
 #include  "ray.h"
 #include  "otypes.h"
+#include  "otspecial.h"
 #include  "resolu.h"
 #include  "ambient.h"
 #include  "random.h"
@@ -21,8 +22,6 @@ static const char	RCSid[] = "$Id: ambient.c,v 2.102 20
 #define	 OCTSCALE	1.0	/* ceil((valid rad.)/(cube size)) */
 #endif
 
-extern char  *shm_boundary;	/* memory sharing boundary */
-
 #ifndef  MAXASET
 #define	 MAXASET	4095	/* maximum number of elements in ambient set */
 #endif
@@ -36,47 +35,19 @@ static AMBTREE	atrunk;		/* our ambient trunk node */
 static FILE  *ambfp = NULL;	/* ambient file pointer */
 static int  nunflshed = 0;	/* number of unflushed ambient values */
 
-#ifndef SORT_THRESH
-#ifdef SMLMEM
-#define SORT_THRESH	((16L<<20)/sizeof(AMBVAL))
-#else
-#define SORT_THRESH	((64L<<20)/sizeof(AMBVAL))
-#endif
-#endif
-#ifndef SORT_INTVL
-#define SORT_INTVL	(SORT_THRESH<<1)
-#endif
-#ifndef MAX_SORT_INTVL
-#define MAX_SORT_INTVL	(SORT_INTVL<<6)
-#endif
-
-
 static double  avsum = 0.;		/* computed ambient value sum (log) */
 static unsigned int  navsum = 0;	/* number of values in avsum */
 static unsigned int  nambvals = 0;	/* total number of indirect values */
 static unsigned int  nambshare = 0;	/* number of values from file */
-static unsigned long  ambclock = 0;	/* ambient access clock */
-static unsigned long  lastsort = 0;	/* time of last value sort */
-static long  sortintvl = SORT_INTVL;	/* time until next sort */
 static FILE  *ambinp = NULL;		/* auxiliary file for input */
 static long  lastpos = -1;		/* last flush position */
 
-#define MAXACLOCK	(1L<<30)	/* clock turnover value */
-	/*
-	 * Track access times unless we are sharing ambient values
-	 * through memory on a multiprocessor, when we want to avoid
-	 * claiming our own memory (copy on write).  Go ahead anyway
-	 * if more than two thirds of our values are unshared.
-	 * Compile with -Dtracktime=0 to turn this code off.
-	 */
-#ifndef tracktime
-#define tracktime	(shm_boundary == NULL || nambvals > 3*nambshare)
-#endif
-
 #define	 AMBFLUSH	(BUFSIZ/AMBVALSIZ)
 
 #define	 newambval()	(AMBVAL *)malloc(sizeof(AMBVAL))
 
+#define  tfunc(lwr, x, upr)	(((x)-(lwr))/((upr)-(lwr)))
+
 static void initambfile(int creat);
 static void avsave(AMBVAL *av);
 static AMBVAL *avstore(AMBVAL  *aval);
@@ -85,14 +56,18 @@ static void freeambtree(AMBTREE  *atp);
 
 typedef void unloadtf_t(AMBVAL *);
 static unloadtf_t avinsert;
-static unloadtf_t av2list;
 static unloadtf_t avfree;
 static void unloadatree(AMBTREE  *at, unloadtf_t *f);
 
-static int aposcmp(const void *avp1, const void *avp2);
-static int avlmemi(AMBVAL *avaddr);
-static void sortambvals(int always);
+static void sortambvals(void);
 
+static int	plugaleak(RAY *r, AMBVAL *ap, FVECT anorm, double ang);
+static double	sumambient(COLOR acol, RAY *r, FVECT rn, int al,
+				AMBTREE *at, FVECT c0, double s);
+static int	makeambient(COLOR acol, RAY *r, FVECT rn, int al);
+static int	extambient(COLOR cr, AMBVAL *ap, FVECT pv, FVECT nv, 
+				FVECT uvw[3]);
+
 #ifdef  F_SETLKW
 static void aflock(int  typ);
 #endif
@@ -131,8 +106,8 @@ setambacc(				/* set ambient accuracy */
 	newa *= (newa > 0);
 	if (fabs(newa - olda) >= .05*(newa + olda)) {
 		ambacc = newa;
-		if (nambvals > 0)
-			sortambvals(1);		/* rebuild tree */
+		if (ambacc > FTINY && nambvals > 0)
+			sortambvals();		/* rebuild tree */
 	}
 }
 
@@ -219,9 +194,6 @@ ambdone(void)			/* close ambient file and free memory 
 	navsum = 0;
 	nambvals = 0;
 	nambshare = 0;
-	ambclock = 0;
-	lastsort = 0;
-	sortintvl = SORT_INTVL;
 }
 
 
@@ -254,19 +226,7 @@ ambnotify(			/* record new modifier */
 		}
 }
 
-/************ THE FOLLOWING ROUTINES DIFFER BETWEEN NEW & OLD ***************/
 
-#ifndef OLDAMB
-
-#define tfunc(lwr, x, upr)	(((x)-(lwr))/((upr)-(lwr)))
-
-static int	plugaleak(RAY *r, AMBVAL *ap, FVECT anorm, double ang);
-static double	sumambient(COLOR acol, RAY *r, FVECT rn, int al,
-				AMBTREE *at, FVECT c0, double s);
-static int	makeambient(COLOR acol, RAY *r, FVECT rn, int al);
-static int	extambient(COLOR cr, AMBVAL *ap, FVECT pv, FVECT nv, 
-				FVECT uvw[3]);
-
 void
 multambient(		/* compute ambient component & multiply by coef. */
 	COLOR  aval,
@@ -274,9 +234,10 @@ multambient(		/* compute ambient component & multiply 
 	FVECT  nrm
 )
 {
+	static double  logAvgAbsorp = 1;
 	static int  rdepth = 0;			/* ambient recursion */
 	COLOR	acol, caustic;
-	int	ok;
+	int	i, ok;
 	double	d, l;
 
 	/* PMAP: Factor in ambient from photon map, if enabled and ray is
@@ -285,6 +246,9 @@ multambient(		/* compute ambient component & multiply 
 	if (ambPmap(aval, r, rdepth))
 		return;
 
+	if (logAvgAbsorp > 0)			/* exclude in -aw to avoid growth */
+		logAvgAbsorp = log(1.-AVGREFL);
+
 	/* PMAP: Factor in specular-diffuse ambient (caustics) from photon
 	 * map, if enabled and ray is primary, else caustic is zero.  Continue
 	 * with RADIANCE ambient calculation */
@@ -302,22 +266,33 @@ multambient(		/* compute ambient component & multiply 
 		goto dumbamb;
 
 	if (ambacc <= FTINY) {			/* no ambient storage */
+		FVECT	uvd[2];
+		float	dgrad[2], *dgp = NULL;
+
+		if (nrm != r->ron && DOT(nrm,r->ron) < 0.9999)
+			dgp = dgrad;		/* compute rotational grad. */
 		copycolor(acol, aval);
 		rdepth++;
 		ok = doambient(acol, r, r->rweight,
-				NULL, NULL, NULL, NULL, NULL);
+				uvd, NULL, NULL, dgp, NULL);
 		rdepth--;
 		if (!ok)
 			goto dumbamb;
+		if ((ok > 0) & (dgp != NULL)) {	/* apply texture */
+			FVECT	v1;
+			VCROSS(v1, r->ron, nrm);
+			d = 1.0;
+			for (i = 3; i--; )
+				d += v1[i] * (dgp[0]*uvd[0][i] + dgp[1]*uvd[1][i]);
+			if (d >= 0.05)
+				scalecolor(acol, d);
+		}
 		copycolor(aval, acol);
 
 		/* PMAP: add in caustic */
 		addcolor(aval, caustic);
 		return;
 	}
-
-	if (tracktime)				/* sort to minimize thrashing */
-		sortambvals(0);
 						/* interpolate ambient value */
 	setcolor(acol, 0.0, 0.0, 0.0);
 	d = sumambient(acol, r, nrm, rdepth,
@@ -356,13 +331,13 @@ dumbamb:					/* return global value */
 	
 	l = bright(ambval);			/* average in computations */	
 	if (l > FTINY) {
-		d = (log(l)*(double)ambvwt + avsum) /
+		d = (log(l)*(double)ambvwt + avsum + logAvgAbsorp*navsum) /
 				(double)(ambvwt + navsum);
 		d = exp(d) / l;
 		scalecolor(aval, d);
 		multcolor(aval, ambval);	/* apply color of ambval */
 	} else {
-		d = exp( avsum / (double)navsum );
+		d = exp( avsum/(double)navsum + logAvgAbsorp );
 		scalecolor(aval, d);		/* neutral color */
 	}
 }
@@ -401,7 +376,8 @@ plugaleak(RAY *r, AMBVAL *ap, FVECT anorm, double ang)
 	VSUM(rtst.rdir, vdif, anorm, t[1]);	/* further dist. > plane */
 	rtst.rmax = normalize(rtst.rdir);	/* short ray test */
 	while (localhit(&rtst, &thescene)) {	/* check for occluder */
-		if (rtst.ro->omod != OVOID &&
+		OBJREC	*m = findmaterial(rtst.ro);
+		if (m != NULL && !istransp(m->otype) && !isBSDFproxy(m) &&
 				(rtst.clipset == NULL ||
 					!inset(rtst.clipset, rtst.ro->omod)))
 			return(1);		/* plug light leak */
@@ -459,9 +435,6 @@ sumambient(		/* get interpolated ambient value */
 		double	u, v, d, delta_r2, delta_t2;
 		COLOR	ct;
 		FVECT	uvw[3];
-					/* record access */
-		if (tracktime)
-			av->latick = ambclock;
 		/*
 		 *  Ambient level test
 		 */
@@ -483,7 +456,7 @@ sumambient(		/* get interpolated ambient value */
 		 */
 		VSUB(ck0, r->rop, av->pos);
 		d = DOT(ck0, uvw[2]);
-		if (d < -minarad*ambacc-.001)
+		if (d < -minarad*ambacc)
 			continue;
 		d /= av->rad[0];
 		delta_t2 = d*d;
@@ -570,6 +543,7 @@ extambient(		/* extrapolate value at pv, nv */
 )
 {
 	const double	min_d = 0.05;
+	const double	max_d = 20.;
 	static FVECT	my_uvw[3];
 	FVECT		v1;
 	int		i;
@@ -589,8 +563,10 @@ extambient(		/* extrapolate value at pv, nv */
 	for (i = 3; i--; )
 		d += v1[i] * (ap->gdir[0]*uvw[0][i] + ap->gdir[1]*uvw[1][i]);
 	
-	if (d < min_d)			/* should not use if we can avoid it */
+	if (d < min_d)			/* clamp min/max scaling */
 		d = min_d;
+	else if (d > max_d)
+		d = max_d;
 	copycolor(cr, ap->val);
 	scalecolor(cr, d);
 	return(d > min_d);
@@ -640,337 +616,7 @@ avinsert(				/* insert ambient value in our tree */
 }
 
 
-#else /* ! NEWAMB */
-
-static double	sumambient(COLOR acol, RAY *r, FVECT rn, int al,
-				AMBTREE *at, FVECT c0, double s);
-static double	makeambient(COLOR acol, RAY *r, FVECT rn, int al);
-static void	extambient(COLOR cr, AMBVAL *ap, FVECT pv, FVECT nv);
-
-
-void
-multambient(		/* compute ambient component & multiply by coef. */
-	COLOR  aval,
-	RAY  *r,
-	FVECT  nrm
-)
-{
-	static int  rdepth = 0;			/* ambient recursion */
-	COLOR	acol, caustic;
-	double	d, l;
-
-	/* PMAP: Factor in ambient from global photon map (if enabled) and return
-	 * as all ambient components accounted for */
-	if (ambPmap(aval, r, rdepth))
-		return;
-
-	/* PMAP: Otherwise factor in ambient from caustic photon map
-	 * (ambPmapCaustic() returns zero if caustic photons disabled) and
-	 * continue with RADIANCE ambient calculation */
-	copycolor(caustic, aval);
-	ambPmapCaustic(caustic, r, rdepth);
-	
-	if (ambdiv <= 0)			/* no ambient calculation */
-		goto dumbamb;
-						/* check number of bounces */
-	if (rdepth >= ambounce)
-		goto dumbamb;
-						/* check ambient list */
-	if (ambincl != -1 && r->ro != NULL &&
-			ambincl != inset(ambset, r->ro->omod))
-		goto dumbamb;
-
-	if (ambacc <= FTINY) {			/* no ambient storage */
-		copycolor(acol, aval);
-		rdepth++;
-		d = doambient(acol, r, r->rweight, NULL, NULL);
-		rdepth--;
-		if (d <= FTINY)
-			goto dumbamb;
-		copycolor(aval, acol);		
-	
-	   /* PMAP: add in caustic */
-		addcolor(aval, caustic);	
-		return;
-	}
-
-	if (tracktime)				/* sort to minimize thrashing */
-		sortambvals(0);
-						/* interpolate ambient value */
-	setcolor(acol, 0.0, 0.0, 0.0);
-	d = sumambient(acol, r, nrm, rdepth,
-			&atrunk, thescene.cuorg, thescene.cusize);
-			
-	if (d > FTINY) {
-		d = 1.0/d;
-		scalecolor(acol, d);
-		multcolor(aval, acol);
-		
-		/* PMAP: add in caustic */
-		addcolor(aval, caustic);	
-		return;
-	}
-	
-	rdepth++;				/* need to cache new value */
-	d = makeambient(acol, r, nrm, rdepth-1);
-	rdepth--;
-	
-	if (d > FTINY) {
-		multcolor(aval, acol);		/* got new value */
-
-		/* PMAP: add in caustic */
-		addcolor(aval, caustic);			
-		return;
-	}
-	
-dumbamb:					/* return global value */
-	if ((ambvwt <= 0) | (navsum == 0)) {
-		multcolor(aval, ambval);
-
-		/* PMAP: add in caustic */
-		addcolor(aval, caustic);	
-		return;
-	}
-	
-	l = bright(ambval);			/* average in computations */
-	if (l > FTINY) {
-		d = (log(l)*(double)ambvwt + avsum) /
-				(double)(ambvwt + navsum);
-		d = exp(d) / l;
-		scalecolor(aval, d);
-		multcolor(aval, ambval);	/* apply color of ambval */
-	} else {
-		d = exp( avsum / (double)navsum );
-		scalecolor(aval, d);		/* neutral color */
-	}
-}
-
-
-static double
-sumambient(	/* get interpolated ambient value */
-	COLOR  acol,
-	RAY  *r,
-	FVECT  rn,
-	int  al,
-	AMBTREE	 *at,
-	FVECT  c0,
-	double	s
-)
-{
-	double	d, e1, e2, wt, wsum;
-	COLOR  ct;
-	FVECT  ck0;
-	int  i;
-	int  j;
-	AMBVAL	 *av;
-
-	wsum = 0.0;
-					/* do this node */
-	for (av = at->alist; av != NULL; av = av->next) {
-		double	rn_dot = -2.0;
-		if (tracktime)
-			av->latick = ambclock;
-		/*
-		 *  Ambient level test.
-		 */
-		if (av->lvl > al ||	/* list sorted, so this works */
-				(av->lvl == al) & (av->weight < 0.9*r->rweight))
-			break;
-		/*
-		 *  Ambient radius test.
-		 */
-		VSUB(ck0, av->pos, r->rop);
-		e1 = DOT(ck0, ck0) / (av->rad * av->rad);
-		if (e1 > ambacc*ambacc*1.21)
-			continue;
-		/*
-		 *  Direction test using closest normal.
-		 */
-		d = DOT(av->dir, r->ron);
-		if (rn != r->ron) {
-			rn_dot = DOT(av->dir, rn);
-			if (rn_dot > 1.0-FTINY)
-				rn_dot = 1.0-FTINY;
-			if (rn_dot >= d-FTINY) {
-				d = rn_dot;
-				rn_dot = -2.0;
-			}
-		}
-		e2 = (1.0 - d) * r->rweight;
-		if (e2 < 0.0)
-			e2 = 0.0;
-		else if (e1 + e2 > ambacc*ambacc*1.21)
-			continue;
-		/*
-		 *  Ray behind test.
-		 */
-		d = 0.0;
-		for (j = 0; j < 3; j++)
-			d += (r->rop[j] - av->pos[j]) *
-					(av->dir[j] + r->ron[j]);
-		if (d*0.5 < -minarad*ambacc-.001)
-			continue;
-		/*
-		 *  Jittering final test reduces image artifacts.
-		 */
-		e1 = sqrt(e1);
-		e2 = sqrt(e2);
-		wt = e1 + e2;
-		if (wt > ambacc*(.9+.2*urand(9015+samplendx)))
-			continue;
-		/*
-		 *  Recompute directional error using perturbed normal
-		 */
-		if (rn_dot > 0.0) {
-			e2 = sqrt((1.0 - rn_dot)*r->rweight);
-			wt = e1 + e2;
-		}
-		if (wt <= 1e-3)
-			wt = 1e3;
-		else
-			wt = 1.0 / wt;
-		wsum += wt;
-		extambient(ct, av, r->rop, rn);
-		scalecolor(ct, wt);
-		addcolor(acol, ct);
-	}
-	if (at->kid == NULL)
-		return(wsum);
-					/* do children */
-	s *= 0.5;
-	for (i = 0; i < 8; i++) {
-		for (j = 0; j < 3; j++) {
-			ck0[j] = c0[j];
-			if (1<<j & i)
-				ck0[j] += s;
-			if (r->rop[j] < ck0[j] - OCTSCALE*s)
-				break;
-			if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
-				break;
-		}
-		if (j == 3)
-			wsum += sumambient(acol, r, rn, al,
-						at->kid+i, ck0, s);
-	}
-	return(wsum);
-}
-
-
-static double
-makeambient(		/* make a new ambient value for storage */
-	COLOR  acol,
-	RAY  *r,
-	FVECT  rn,
-	int  al
-)
-{
-	AMBVAL	amb;
-	FVECT	gp, gd;
-	int	i;
-
-	amb.weight = 1.0;			/* compute weight */
-	for (i = al; i-- > 0; )
-		amb.weight *= AVGREFL;
-	if (r->rweight < 0.1*amb.weight)	/* heuristic override */
-		amb.weight = 1.25*r->rweight;
-	setcolor(acol, AVGREFL, AVGREFL, AVGREFL);
-						/* compute ambient */
-	amb.rad = doambient(acol, r, amb.weight, gp, gd);
-	if (amb.rad <= FTINY) {
-		setcolor(acol, 0.0, 0.0, 0.0);
-		return(0.0);
-	}
-	scalecolor(acol, 1./AVGREFL);		/* undo assumed reflectance */
-						/* store value */
-	VCOPY(amb.pos, r->rop);
-	VCOPY(amb.dir, r->ron);
-	amb.lvl = al;
-	copycolor(amb.val, acol);
-	VCOPY(amb.gpos, gp);
-	VCOPY(amb.gdir, gd);
-						/* insert into tree */
-	avsave(&amb);				/* and save to file */
-	if (rn != r->ron)
-		extambient(acol, &amb, r->rop, rn);	/* texture */
-	return(amb.rad);
-}
-
-
 static void
-extambient(		/* extrapolate value at pv, nv */
-	COLOR  cr,
-	AMBVAL	 *ap,
-	FVECT  pv,
-	FVECT  nv
-)
-{
-	FVECT  v1;
-	int  i;
-	double	d;
-
-	d = 1.0;			/* zeroeth order */
-					/* gradient due to translation */
-	for (i = 0; i < 3; i++)
-		d += ap->gpos[i]*(pv[i]-ap->pos[i]);
-					/* gradient due to rotation */
-	VCROSS(v1, ap->dir, nv);
-	d += DOT(ap->gdir, v1);
-	if (d <= 0.0) {
-		setcolor(cr, 0.0, 0.0, 0.0);
-		return;
-	}
-	copycolor(cr, ap->val);
-	scalecolor(cr, d);
-}
-
-
-static void
-avinsert(				/* insert ambient value in our tree */
-	AMBVAL *av
-)
-{
-	AMBTREE  *at;
-	AMBVAL  *ap;
-	AMBVAL  avh;
-	FVECT  ck0;
-	double	s;
-	int  branch;
-	int  i;
-
-	if (av->rad <= FTINY)
-		error(CONSISTENCY, "zero ambient radius in avinsert");
-	at = &atrunk;
-	VCOPY(ck0, thescene.cuorg);
-	s = thescene.cusize;
-	while (s*(OCTSCALE/2) > av->rad*ambacc) {
-		if (at->kid == NULL)
-			if ((at->kid = newambtree()) == NULL)
-				error(SYSTEM, "out of memory in avinsert");
-		s *= 0.5;
-		branch = 0;
-		for (i = 0; i < 3; i++)
-			if (av->pos[i] > ck0[i] + s) {
-				ck0[i] += s;
-				branch |= 1 << i;
-			}
-		at = at->kid + branch;
-	}
-	avh.next = at->alist;		/* order by increasing level */
-	for (ap = &avh; ap->next != NULL; ap = ap->next)
-		if ( ap->next->lvl > av->lvl ||
-				(ap->next->lvl == av->lvl) &
-				(ap->next->weight <= av->weight) )
-			break;
-	av->next = ap->next;
-	ap->next = (AMBVAL*)av;
-	at->alist = avh.next;
-}
-
-#endif	/* ! NEWAMB */
-
-/************* FOLLOWING ROUTINES SAME FOR NEW & OLD METHODS ***************/
-
-static void
 initambfile(		/* initialize ambient file */
 	int  cre8
 )
@@ -993,6 +639,10 @@ initambfile(		/* initialize ambient file */
 				ambvwt, ambounce, ambacc);
 		fprintf(ambfp, "-ad %d -as %d -ar %d ",
 				ambdiv, ambssamp, ambres);
+		fprintf(ambfp, "-dr %d -ds %g -dt %g -dc %g ", directrelay,
+				srcsizerat, shadthresh, shadcert);
+		fprintf(ambfp, "-ss %g -st %g -lr %d -lw %g ", specjitter,
+				specthresh, maxdepth, minweight);
 		if (octname != NULL)
 			fputs(octname, ambfp);
 		fputc('\n', ambfp);
@@ -1036,7 +686,6 @@ avstore(				/* allocate memory and save aval */
 	if ((av = newambval()) == NULL)
 		error(SYSTEM, "out of memory in avstore");
 	*av = *aval;
-	av->latick = ambclock;
 	av->next = NULL;
 	nambvals++;
 	d = bright(av->val);
@@ -1109,178 +758,24 @@ unloadatree(			/* unload an ambient value tree */
 }
 
 
-static struct avl {
-	AMBVAL	*p;
-	unsigned long	t;
-}	*avlist1;			/* ambient value list with ticks */
-static AMBVAL	**avlist2;		/* memory positions for sorting */
-static int	i_avlist;		/* index for lists */
-
-static int alatcmp(const void *av1, const void *av2);
-
 static void
 avfree(AMBVAL *av)
 {
 	free(av);
 }
 
+
 static void
-av2list(
-	AMBVAL *av
-)
+sortambvals(void)			/* resort ambient values */
 {
-#ifdef DEBUG
-	if (i_avlist >= nambvals)
-		error(CONSISTENCY, "too many ambient values in av2list1");
-#endif
-	avlist1[i_avlist].p = avlist2[i_avlist] = (AMBVAL*)av;
-	avlist1[i_avlist++].t = av->latick;
-}
+	AMBTREE  oldatrunk = atrunk;
 
-
-static int
-alatcmp(			/* compare ambient values for MRA */
-	const void *av1,
-	const void *av2
-)
-{
-	long  lc = ((struct avl *)av2)->t - ((struct avl *)av1)->t;
-	return(lc<0 ? -1 : lc>0 ? 1 : 0);
+	atrunk.alist = NULL;
+	atrunk.kid = NULL;
+	unloadatree(&oldatrunk, avinsert);
 }
 
 
-/* GW NOTE 2002/10/3:
- * I used to compare AMBVAL pointers, but found that this was the
- * cause of a serious consistency error with gcc, since the optimizer
- * uses some dangerous trick in pointer subtraction that
- * assumes pointers differ by exact struct size increments.
- */
-static int
-aposcmp(			/* compare ambient value positions */
-	const void	*avp1,
-	const void	*avp2
-)
-{
-	long	diff = *(char * const *)avp1 - *(char * const *)avp2;
-	if (diff < 0)
-		return(-1);
-	return(diff > 0);
-}
-
-
-static int
-avlmemi(				/* find list position from address */
-	AMBVAL	*avaddr
-)
-{
-	AMBVAL  **avlpp;
-
-	avlpp = (AMBVAL **)bsearch(&avaddr, avlist2,
-			nambvals, sizeof(AMBVAL *), aposcmp);
-	if (avlpp == NULL)
-		error(CONSISTENCY, "address not found in avlmemi");
-	return(avlpp - avlist2);
-}
-
-
-static void
-sortambvals(			/* resort ambient values */
-	int	always
-)
-{
-	AMBTREE  oldatrunk;
-	AMBVAL	tav, *tap, *pnext;
-	int	i, j;
-					/* see if it's time yet */
-	if (!always && (ambclock++ < lastsort+sortintvl ||
-			nambvals < SORT_THRESH))
-		return;
-	/*
-	 * The idea here is to minimize memory thrashing
-	 * in VM systems by improving reference locality.
-	 * We do this by periodically sorting our stored ambient
-	 * values in memory in order of most recently to least
-	 * recently accessed.  This ordering was chosen so that new
-	 * ambient values (which tend to be less important) go into
-	 * higher memory with the infrequently accessed values.
-	 *	Since we expect our values to need sorting less
-	 * frequently as the process continues, we double our
-	 * waiting interval after each call.
-	 * 	This routine is also called by setambacc() with
-	 * the "always" parameter set to 1 so that the ambient
-	 * tree will be rebuilt with the new accuracy parameter.
-	 */
-	if (tracktime) {		/* allocate pointer arrays to sort */
-		avlist2 = (AMBVAL **)malloc(nambvals*sizeof(AMBVAL *));
-		avlist1 = (struct avl *)malloc(nambvals*sizeof(struct avl));
-	} else {
-		avlist2 = NULL;
-		avlist1 = NULL;
-	}
-	if (avlist1 == NULL) {		/* no time tracking -- rebuild tree? */
-		if (avlist2 != NULL)
-			free(avlist2);
-		if (always) {		/* rebuild without sorting */
-			oldatrunk = atrunk;
-			atrunk.alist = NULL;
-			atrunk.kid = NULL;
-			unloadatree(&oldatrunk, avinsert);
-		}
-	} else {			/* sort memory by last access time */
-		/*
-		 * Sorting memory is tricky because it isn't contiguous.
-		 * We have to sort an array of pointers by MRA and also
-		 * by memory position.  We then copy values in "loops"
-		 * to minimize memory hits.  Nevertheless, we will visit
-		 * everyone at least twice, and this is an expensive process
-		 * when we're thrashing, which is when we need to do it.
-		 */
-#ifdef DEBUG
-		sprintf(errmsg, "sorting %u ambient values at ambclock=%lu...",
-				nambvals, ambclock);
-		eputs(errmsg);
-#endif
-		i_avlist = 0;
-		unloadatree(&atrunk, av2list);	/* empty current tree */
-#ifdef DEBUG
-		if (i_avlist < nambvals)
-			error(CONSISTENCY, "missing ambient values in sortambvals");
-#endif
-		qsort(avlist1, nambvals, sizeof(struct avl), alatcmp);
-		qsort(avlist2, nambvals, sizeof(AMBVAL *), aposcmp);
-		for (i = 0; i < nambvals; i++) {
-			if (avlist1[i].p == NULL)
-				continue;
-			tap = avlist2[i];
-			tav = *tap;
-			for (j = i; (pnext = avlist1[j].p) != tap;
-					j = avlmemi(pnext)) {
-				*(avlist2[j]) = *pnext;
-				avinsert(avlist2[j]);
-				avlist1[j].p = NULL;
-			}
-			*(avlist2[j]) = tav;
-			avinsert(avlist2[j]);
-			avlist1[j].p = NULL;
-		}
-		free(avlist1);
-		free(avlist2);
-						/* compute new sort interval */
-		sortintvl = ambclock - lastsort;
-		if (sortintvl >= MAX_SORT_INTVL/2)
-			sortintvl = MAX_SORT_INTVL;
-		else
-			sortintvl <<= 1;	/* wait twice as long next */
-#ifdef DEBUG
-		eputs("done\n");
-#endif
-	}
-	if (ambclock >= MAXACLOCK)
-		ambclock = MAXACLOCK/2;
-	lastsort = ambclock;
-}
-
-
 #ifdef	F_SETLKW
 
 static void
@@ -1292,9 +787,14 @@ aflock(			/* lock/unlock ambient file */
 
 	if (typ == fls.l_type)		/* already called? */
 		return;
+
 	fls.l_type = typ;
-	if (fcntl(fileno(ambfp), F_SETLKW, &fls) < 0)
-		error(SYSTEM, "cannot (un)lock ambient file");
+	do
+		if (fcntl(fileno(ambfp), F_SETLKW, &fls) != -1)
+			return;
+	while (errno == EINTR);
+	
+	error(SYSTEM, "cannot (un)lock ambient file");
 }
 
 
@@ -1313,10 +813,10 @@ ambsync(void)			/* synchronize ambient file */
 	if ((flen = lseek(fileno(ambfp), (off_t)0, SEEK_END)) < 0)
 		goto seekerr;
 	if ((n = flen - lastpos) > 0) {		/* file has grown */
-		if (ambinp == NULL) {		/* use duplicate filedes */
-			ambinp = fdopen(dup(fileno(ambfp)), "r");
+		if (ambinp == NULL) {		/* get new file pointer */
+			ambinp = fopen(ambfile, "rb");
 			if (ambinp == NULL)
-				error(SYSTEM, "fdopen failed in ambsync");
+				error(SYSTEM, "fopen failed in ambsync");
 		}
 		if (fseek(ambinp, lastpos, SEEK_SET) < 0)
 			goto seekerr;
@@ -1331,24 +831,18 @@ ambsync(void)			/* synchronize ambient file */
 			avstore(&avs);
 			n -= AMBVALSIZ;
 		}
-		lastpos = flen - n;
-		/*** seek always as safety measure
-		if (n) ***/			/* alignment */
-			if (lseek(fileno(ambfp), (off_t)lastpos, SEEK_SET) < 0)
-				goto seekerr;
+		lastpos = flen - n;		/* check alignment */
+		if (n && lseek(fileno(ambfp), (off_t)lastpos, SEEK_SET) < 0)
+			goto seekerr;
 	}
 	n = fflush(ambfp);			/* calls write() at last */
-	if (n != EOF)
-		lastpos += (long)nunflshed*AMBVALSIZ;
-	else if ((lastpos = lseek(fileno(ambfp), (off_t)0, SEEK_CUR)) < 0)
-		goto seekerr;
-		
+	lastpos += (long)nunflshed*AMBVALSIZ;
 	aflock(F_UNLCK);			/* release file */
 	nunflshed = 0;
 	return(n);
 seekerr:
 	error(SYSTEM, "seek failed in ambsync");
-	return -1; /* pro forma return */
+	return(EOF);	/* pro forma return */
 }
 
 #else	/* ! F_SETLKW */