src/hd/rholo3.c

/* Copyright (c) 1997 Silicon Graphics, Inc. */

#ifndef lint
static char SCCSid[] = "$SunId$ SGI";
#endif

/*
 * Routines for tracking beam compuatations
 */

#include "rholo.h"

#define abs(x)          ((x) > 0 ? (x) : -(x))
#define sgn(x)          ((x) > 0 ? 1 : (x) < 0 ? -1 : 0)

static PACKHEAD *complist=NULL; /* list of beams to compute */
static int      complen=0;      /* length of complist */
static int      listpos=0;      /* current list position for next_packet */
static int      lastin= -1;     /* last ordered position in list */


int
beamcmp(b0, b1)                 /* comparison for descending compute order */
register PACKHEAD       *b0, *b1;
{
        return( b1->nr*(b0->nc+1) - b0->nr*(b1->nc+1) );
}


int
dispbeam(b, hp, bi)                     /* display a holodeck beam */
register BEAM   *b;
HOLO    *hp;
int     bi;
{
        static int      n = 0;
        static PACKHEAD *p = NULL;

        if (b == NULL)
                return;
        if (b->nrm > n) {               /* (re)allocate packet holder */
                n = b->nrm;
                if (p == NULL) p = (PACKHEAD *)malloc(packsiz(n));
                else p = (PACKHEAD *)realloc((char *)p, packsiz(n));
                if (p == NULL)
                        error(SYSTEM, "out of memory in dispbeam");
        }
                                        /* assign packet fields */
        bcopy((char *)hdbray(b), (char *)packra(p), b->nrm*sizeof(RAYVAL));
        p->nr = p->nc = b->nrm;
        for (p->hd = 0; hdlist[p->hd] != hp; p->hd++)
                if (hdlist[p->hd] == NULL)
                        error(CONSISTENCY, "unregistered holodeck in dispbeam");
        p->bi = bi;
        disp_packet(p);                 /* display it */
}


bundle_set(op, clist, nents)    /* bundle set operation */
int     op;
register PACKHEAD       *clist;
int     nents;
{
        register int    i, n;

        switch (op) {
        case BS_NEW:                    /* new computation set */
                if (complen)
                        free((char *)complist);
                if (nents <= 0) {
                        complist = NULL;
                        listpos = complen = 0;
                        lastin = -1;
                        return;
                }
                complist = (PACKHEAD *)malloc(nents*sizeof(PACKHEAD));
                if (complist == NULL)
                        goto memerr;
                bcopy((char *)clist, (char *)complist, nents*sizeof(PACKHEAD));
                complen = nents;        /* finish initialization below */
                break;
        case BS_ADD:                    /* add to computation set */
        case BS_ADJ:                    /* adjust set quantities */
                if (nents <= 0)
                        return;
                                        /* merge any common members */
                for (n = 0; n < nents; n++) {
                        for (i = 0; i < complen; i++)
                                if (clist[n].bi == complist[i].bi &&
                                                clist[n].hd == complist[i].hd) {
                                        int     oldnr = complist[i].nr;
                                        if (op == BS_ADD)
                                                complist[i].nr += clist[n].nr;
                                        else /* op == BS_ADJ */
                                                complist[i].nr = clist[n].nr;
                                        clist[n].nr = 0;
                                        clist[n].nc = complist[i].nc;
                                        if (complist[i].nr != oldnr)
                                                lastin = -1;    /* flag sort */
                                        break;
                                }
                        if (i >= complen)
                                clist[n].nc = bnrays(hdlist[clist[n].hd],
                                                clist[n].bi);
                }
                                        /* sort updated list */
                sortcomplist();
                                        /* sort new entries */
                qsort((char *)clist, nents, sizeof(PACKHEAD), beamcmp);
                                        /* what can't we satisfy? */
                for (n = 0; n < nents && clist[n].nr > clist[n].nc; n++)
                        ;
                if (op == BS_ADJ)
                        nents = n;
                if (n) {                /* allocate space for merged list */
                        PACKHEAD        *newlist;
                        newlist = (PACKHEAD *)malloc(
                                        (complen+n)*sizeof(PACKHEAD) );
                        if (newlist == NULL)
                                goto memerr;
                                                /* merge lists */
                        mergeclists(newlist, clist, n, complist, complen);
                        if (complen)
                                free((char *)complist);
                        complist = newlist;
                        complen += n;
                }
                listpos = 0;
                lastin = complen-1;     /* list is now sorted */
                break;
        case BS_DEL:                    /* delete from computation set */
                if (nents <= 0)
                        return;
                                        /* find each member */
                for (i = 0; i < complen; i++)
                        for (n = 0; n < nents; n++)
                                if (clist[n].bi == complist[i].bi &&
                                                clist[n].hd == complist[i].hd) {
                                        if (clist[n].nr == 0 ||
                                                clist[n].nr >= complist[i].nr)
                                                complist[i].nr = 0;
                                        else
                                                complist[i].nr -= clist[n].nr;
                                        lastin = -1;    /* flag full sort */
                                        break;
                                }
                return;                 /* no display */
        default:
                error(CONSISTENCY, "bundle_set called with unknown operation");
        }
        if (outdev != NULL) {           /* load and display beams we have */
                register HDBEAMI        *hb;

                hb = (HDBEAMI *)malloc(nents*sizeof(HDBEAMI));
                for (i = 0; i < nents; i++) {
                        hb[i].h = hdlist[clist[i].hd];
                        hb[i].b = clist[i].bi;
                }
                hdloadbeams(hb, nents, dispbeam);
                free((char *)hb);
        }
        if (op == BS_NEW) {
                done_packets(flush_queue());    /* empty queue, so we can... */
                for (i = 0; i < complen; i++)   /* ...get number computed */
                        complist[i].nc = bnrays(hdlist[complist[i].hd],
                                                complist[i].bi);
                listpos = 0;
                lastin = -1;            /* flag for initial sort */
        }
        return;
memerr:
        error(SYSTEM, "out of memory in bundle_set");
}


double
beamvolume(hp, bi)      /* compute approximate volume of a beam */
HOLO    *hp;
int     bi;
{
        GCOORD  gc[2];
        FVECT   cp[4], edgeA, edgeB, cent[2];
        FVECT   v, crossp[2], diffv;
        double  vol[2];
        register int    i;
                                        /* get grid coordinates */
        if (!hdbcoord(gc, hp, bi))
                error(CONSISTENCY, "bad beam index in beamvolume");
        for (i = 0; i < 2; i++) {       /* compute cell area vectors */
                hdcell(cp, hp, gc+i);
                VSUM(edgeA, cp[1], cp[0], -1.0);
                VSUM(edgeB, cp[3], cp[1], -1.0);
                fcross(crossp[i], edgeA, edgeB);
                                        /* compute center */
                cent[i][0] = 0.5*(cp[0][0] + cp[2][0]);
                cent[i][1] = 0.5*(cp[0][1] + cp[2][1]);
                cent[i][2] = 0.5*(cp[0][2] + cp[2][2]);
        }
                                        /* compute difference vector */
        VSUM(diffv, cent[1], cent[0], -1.0);
        for (i = 0; i < 2; i++) {       /* compute volume contributions */
                vol[i] = 0.5*DOT(crossp[i], diffv);
                if (vol[i] < 0.) vol[i] = -vol[i];
        }
        return(vol[0] + vol[1]);        /* return total volume */
}


init_global()                   /* initialize global ray computation */
{
        long    wtotal = 0;
        double  frac;
        int     i;
        register int    j, k;
                                        /* free old list */
        if (complen > 0)
                free((char *)complist);
                                        /* allocate beam list */
        complen = 0;
        for (j = 0; hdlist[j] != NULL; j++)
                complen += nbeams(hdlist[j]);
        complist = (PACKHEAD *)malloc(complen*sizeof(PACKHEAD));
        if (complist == NULL)
                error(SYSTEM, "out of memory in init_global");
                                        /* compute beam weights */
        k = 0;
        for (j = 0; hdlist[j] != NULL; j++) {
                frac = 512. * hdlist[j]->wg[0] *
                                hdlist[j]->wg[1] * hdlist[j]->wg[2];
                if (frac < 0.) frac = -frac;
                for (i = nbeams(hdlist[j]); i > 0; i--) {
                        complist[k].hd = j;
                        complist[k].bi = i;
                        complist[k].nr = frac*beamvolume(hdlist[j], i) + 0.5;
                        wtotal += complist[k++].nr;
                }
        }
                                        /* adjust weights */
        if (vdef(DISKSPACE))
                frac = 1024.*1024.*vflt(DISKSPACE) / (wtotal*sizeof(RAYVAL));
        else
                frac = 1024.*1024.*16384. / (wtotal*sizeof(RAYVAL));
        while (k--)
                complist[k].nr = frac * complist[k].nr;
        listpos = 0; lastin = -1;       /* flag initial sort */
}


mergeclists(cdest, cl1, n1, cl2, n2)    /* merge two sorted lists */
PACKHEAD        *cdest;
PACKHEAD        *cl1, *cl2;
int     n1, n2;
{
        int     cmp;

        while (n1 | n2) {
                if (!n1) cmp = 1;
                else if (!n2) cmp = -1;
                else cmp = beamcmp(cl1, cl2);
                if (cmp > 0) {
                        copystruct(cdest, cl2);
                        cl2++; n2--;
                } else {
                        copystruct(cdest, cl1);
                        cl1++; n1--;
                }
                cdest++;
        }
}


sortcomplist()                  /* fix our list order */
{
        PACKHEAD        *list2;
        register int    i;

        if (complen <= 0)       /* check to see if there is even a list */
                return;
        if (lastin < 0 || listpos*4 >= complen*3)
                qsort((char *)complist, complen, sizeof(PACKHEAD), beamcmp);
        else if (listpos) {     /* else sort and merge sublist */
                list2 = (PACKHEAD *)malloc(listpos*sizeof(PACKHEAD));
                if (list2 == NULL)
                        error(SYSTEM, "out of memory in sortcomplist");
                bcopy((char *)complist,(char *)list2,listpos*sizeof(PACKHEAD));
                qsort((char *)list2, listpos, sizeof(PACKHEAD), beamcmp);
                mergeclists(complist, list2, listpos,
                                complist+listpos, complen-listpos);
                free((char *)list2);
        }
                                        /* drop satisfied requests */
        for (i = complen; i-- && complist[i].nr <= complist[i].nc; )
                ;
        if (i < 0) {
                free((char *)complist);
                complist = NULL;
                complen = 0;
        } else if (i < complen-1) {
                list2 = (PACKHEAD *)realloc((char *)complist,
                                (i+1)*sizeof(PACKHEAD));
                if (list2 != NULL) {
                        complist = list2;
                        complen = i+1;
                }
        }
        listpos = 0; lastin = i;
}


/*
 * The following routine works on the assumption that the bundle weights are
 * more or less evenly distributed, such that computing a packet causes
 * a given bundle to move way down in the computation order.  We keep
 * track of where the computed bundle with the highest priority would end
 * up, and if we get further in our compute list than this, we resort the
 * list and start again from the beginning.  Since
 * a merge sort is used, the sorting costs are minimal.
 */
next_packet(p)                  /* prepare packet for computation */
register PACKET *p;
{
        register int    i;

        if (listpos > lastin)           /* time to sort the list */
                sortcomplist();
        if (complen <= 0)
                return(0);
        p->hd = complist[listpos].hd;
        p->bi = complist[listpos].bi;
        p->nc = complist[listpos].nc;
        p->nr = complist[listpos].nr - p->nc;
        if (p->nr <= 0)
                return(0);
        if (p->nr > RPACKSIZ)
                p->nr = RPACKSIZ;
        complist[listpos].nc += p->nr;  /* find where this one would go */
        while (lastin > listpos && 
                        beamcmp(complist+lastin, complist+listpos) > 0)
                lastin--;
        listpos++;
        return(1);
}
Revision:	3.15
Committed:	Fri Dec 19 09:55:36 1997 UTC (27 years, 10 months ago) by gregl
Content type:	text/plain
Branch:	MAIN
Changes since 3.14:	+2 -5 lines
Log Message:	simplified beam volume calculation slightly and fixed bug in init_global()
#	User	Rev	Content
1	gregl	3.1	/* Copyright (c) 1997 Silicon Graphics, Inc. */
2
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ SGI";
5			#endif
6
7			/*
8			* Routines for tracking beam compuatations
9			*/
10
11			#include "rholo.h"
12
13			#define abs(x) ((x) > 0 ? (x) : -(x))
14			#define sgn(x) ((x) > 0 ? 1 : (x) < 0 ? -1 : 0)
15
16	gregl	3.4	static PACKHEAD complist=NULL; / list of beams to compute */
17			static int complen=0; /* length of complist */
18			static int listpos=0; /* current list position for next_packet */
19			static int lastin= -1; /* last ordered position in list */
20	gregl	3.1
21
22			int
23	gregl	3.2	beamcmp(b0, b1) /* comparison for descending compute order */
24			register PACKHEAD b0, b1;
25			{
26	gregl	3.11	return( b1->nr(b0->nc+1) - b0->nr(b1->nc+1) );
27	gregl	3.2	}
28
29
30	gregl	3.14	int
31			dispbeam(b, hp, bi) /* display a holodeck beam */
32			register BEAM *b;
33			HOLO *hp;
34			int bi;
35			{
36			static int n = 0;
37			static PACKHEAD *p = NULL;
38
39			if (b == NULL)
40			return;
41			if (b->nrm > n) { /* (re)allocate packet holder */
42			n = b->nrm;
43			if (p == NULL) p = (PACKHEAD *)malloc(packsiz(n));
44			else p = (PACKHEAD )realloc((char )p, packsiz(n));
45			if (p == NULL)
46			error(SYSTEM, "out of memory in dispbeam");
47			}
48			/* assign packet fields */
49			bcopy((char )hdbray(b), (char )packra(p), b->nrm*sizeof(RAYVAL));
50			p->nr = p->nc = b->nrm;
51			for (p->hd = 0; hdlist[p->hd] != hp; p->hd++)
52			if (hdlist[p->hd] == NULL)
53			error(CONSISTENCY, "unregistered holodeck in dispbeam");
54			p->bi = bi;
55			disp_packet(p); /* display it */
56			}
57
58
59	gregl	3.2	bundle_set(op, clist, nents) /* bundle set operation */
60			int op;
61	gregl	3.14	register PACKHEAD *clist;
62	gregl	3.2	int nents;
63			{
64			register int i, n;
65
66			switch (op) {
67			case BS_NEW: /* new computation set */
68			if (complen)
69			free((char *)complist);
70			if (nents <= 0) {
71			complist = NULL;
72			listpos = complen = 0;
73			lastin = -1;
74			return;
75			}
76			complist = (PACKHEAD )malloc(nentssizeof(PACKHEAD));
77			if (complist == NULL)
78			goto memerr;
79			bcopy((char )clist, (char )complist, nents*sizeof(PACKHEAD));
80	gregl	3.12	complen = nents; /* finish initialization below */
81	gregl	3.2	break;
82			case BS_ADD: /* add to computation set */
83	gregl	3.11	case BS_ADJ: /* adjust set quantities */
84	gregl	3.2	if (nents <= 0)
85			return;
86			/* merge any common members */
87	gregl	3.12	for (n = 0; n < nents; n++) {
88			for (i = 0; i < complen; i++)
89	gregl	3.2	if (clist[n].bi == complist[i].bi &&
90			clist[n].hd == complist[i].hd) {
91	gregl	3.12	int oldnr = complist[i].nr;
92	gregl	3.11	if (op == BS_ADD)
93			complist[i].nr += clist[n].nr;
94			else /* op == BS_ADJ */
95			complist[i].nr = clist[n].nr;
96	gregl	3.2	clist[n].nr = 0;
97	gregl	3.12	clist[n].nc = complist[i].nc;
98			if (complist[i].nr != oldnr)
99			lastin = -1; /* flag sort */
100	gregl	3.2	break;
101			}
102	gregl	3.12	if (i >= complen)
103			clist[n].nc = bnrays(hdlist[clist[n].hd],
104			clist[n].bi);
105	gregl	3.11	}
106	gregl	3.2	/* sort updated list */
107			sortcomplist();
108			/* sort new entries */
109			qsort((char *)clist, nents, sizeof(PACKHEAD), beamcmp);
110			/* what can't we satisfy? */
111	gregl	3.11	for (n = 0; n < nents && clist[n].nr > clist[n].nc; n++)
112	gregl	3.2	;
113	gregl	3.11	if (op == BS_ADJ)
114			nents = n;
115	gregl	3.2	if (n) { /* allocate space for merged list */
116			PACKHEAD *newlist;
117			newlist = (PACKHEAD *)malloc(
118			(complen+n)*sizeof(PACKHEAD) );
119			if (newlist == NULL)
120			goto memerr;
121			/* merge lists */
122			mergeclists(newlist, clist, n, complist, complen);
123			if (complen)
124			free((char *)complist);
125			complist = newlist;
126			complen += n;
127			}
128			listpos = 0;
129			lastin = complen-1; /* list is now sorted */
130			break;
131			case BS_DEL: /* delete from computation set */
132			if (nents <= 0)
133			return;
134			/* find each member */
135			for (i = 0; i < complen; i++)
136			for (n = 0; n < nents; n++)
137			if (clist[n].bi == complist[i].bi &&
138			clist[n].hd == complist[i].hd) {
139			if (clist[n].nr == 0 \|\|
140			clist[n].nr >= complist[i].nr)
141			complist[i].nr = 0;
142			else
143			complist[i].nr -= clist[n].nr;
144			lastin = -1; /* flag full sort */
145			break;
146			}
147			return; /* no display */
148			default:
149			error(CONSISTENCY, "bundle_set called with unknown operation");
150			}
151	gregl	3.14	if (outdev != NULL) { /* load and display beams we have */
152			register HDBEAMI *hb;
153
154			hb = (HDBEAMI )malloc(nentssizeof(HDBEAMI));
155			for (i = 0; i < nents; i++) {
156			hb[i].h = hdlist[clist[i].hd];
157			hb[i].b = clist[i].bi;
158	gregl	3.2	}
159	gregl	3.14	hdloadbeams(hb, nents, dispbeam);
160			free((char *)hb);
161			}
162	gregl	3.11	if (op == BS_NEW) {
163			done_packets(flush_queue()); /* empty queue, so we can... */
164			for (i = 0; i < complen; i++) /* ...get number computed */
165			complist[i].nc = bnrays(hdlist[complist[i].hd],
166			complist[i].bi);
167	gregl	3.12	listpos = 0;
168			lastin = -1; /* flag for initial sort */
169	gregl	3.11	}
170	gregl	3.2	return;
171			memerr:
172			error(SYSTEM, "out of memory in bundle_set");
173			}
174
175
176	gregl	3.13	double
177			beamvolume(hp, bi) /* compute approximate volume of a beam */
178	gregl	3.1	HOLO *hp;
179	gregl	3.13	int bi;
180	gregl	3.1	{
181	gregl	3.13	GCOORD gc[2];
182			FVECT cp[4], edgeA, edgeB, cent[2];
183			FVECT v, crossp[2], diffv;
184			double vol[2];
185			register int i;
186			/* get grid coordinates */
187			if (!hdbcoord(gc, hp, bi))
188			error(CONSISTENCY, "bad beam index in beamvolume");
189			for (i = 0; i < 2; i++) { /* compute cell area vectors */
190			hdcell(cp, hp, gc+i);
191			VSUM(edgeA, cp[1], cp[0], -1.0);
192			VSUM(edgeB, cp[3], cp[1], -1.0);
193			fcross(crossp[i], edgeA, edgeB);
194			/* compute center */
195			cent[i][0] = 0.5*(cp[0][0] + cp[2][0]);
196			cent[i][1] = 0.5*(cp[0][1] + cp[2][1]);
197			cent[i][2] = 0.5*(cp[0][2] + cp[2][2]);
198	gregl	3.1	}
199	gregl	3.13	/* compute difference vector */
200			VSUM(diffv, cent[1], cent[0], -1.0);
201			for (i = 0; i < 2; i++) { /* compute volume contributions */
202	gregl	3.15	vol[i] = 0.5*DOT(crossp[i], diffv);
203	gregl	3.13	if (vol[i] < 0.) vol[i] = -vol[i];
204			}
205			return(vol[0] + vol[1]); /* return total volume */
206	gregl	3.1	}
207
208
209			init_global() /* initialize global ray computation */
210			{
211			long wtotal = 0;
212			double frac;
213	gregl	3.13	int i;
214			register int j, k;
215	gregl	3.3	/* free old list */
216			if (complen > 0)
217			free((char *)complist);
218	gregl	3.1	/* allocate beam list */
219			complen = 0;
220			for (j = 0; hdlist[j] != NULL; j++)
221			complen += nbeams(hdlist[j]);
222			complist = (PACKHEAD )malloc(complensizeof(PACKHEAD));
223			if (complist == NULL)
224			error(SYSTEM, "out of memory in init_global");
225			/* compute beam weights */
226			k = 0;
227	gregl	3.13	for (j = 0; hdlist[j] != NULL; j++) {
228			frac = 512. * hdlist[j]->wg[0] *
229			hdlist[j]->wg[1] * hdlist[j]->wg[2];
230	gregl	3.15	if (frac < 0.) frac = -frac;
231	gregl	3.1	for (i = nbeams(hdlist[j]); i > 0; i--) {
232			complist[k].hd = j;
233			complist[k].bi = i;
234	gregl	3.13	complist[k].nr = frac*beamvolume(hdlist[j], i) + 0.5;
235	gregl	3.1	wtotal += complist[k++].nr;
236			}
237	gregl	3.13	}
238	gregl	3.1	/* adjust weights */
239	gregl	3.12	if (vdef(DISKSPACE))
240	gregl	3.1	frac = 1024.1024.vflt(DISKSPACE) / (wtotal*sizeof(RAYVAL));
241	gregl	3.12	else
242			frac = 1024.1024.16384. / (wtotal*sizeof(RAYVAL));
243			while (k--)
244			complist[k].nr = frac * complist[k].nr;
245	gregl	3.4	listpos = 0; lastin = -1; /* flag initial sort */
246	gregl	3.1	}
247
248
249			mergeclists(cdest, cl1, n1, cl2, n2) /* merge two sorted lists */
250			PACKHEAD *cdest;
251			PACKHEAD cl1, cl2;
252			int n1, n2;
253			{
254			int cmp;
255
256			while (n1 \| n2) {
257			if (!n1) cmp = 1;
258			else if (!n2) cmp = -1;
259			else cmp = beamcmp(cl1, cl2);
260			if (cmp > 0) {
261			copystruct(cdest, cl2);
262			cl2++; n2--;
263			} else {
264			copystruct(cdest, cl1);
265			cl1++; n1--;
266			}
267			cdest++;
268			}
269			}
270
271
272			sortcomplist() /* fix our list order */
273			{
274			PACKHEAD *list2;
275	gregl	3.2	register int i;
276
277	gregl	3.3	if (complen <= 0) /* check to see if there is even a list */
278	gregl	3.2	return;
279	gregl	3.6	if (lastin < 0 \|\| listpos4 >= complen3)
280	gregl	3.1	qsort((char *)complist, complen, sizeof(PACKHEAD), beamcmp);
281			else if (listpos) { /* else sort and merge sublist */
282			list2 = (PACKHEAD )malloc(listpossizeof(PACKHEAD));
283			if (list2 == NULL)
284			error(SYSTEM, "out of memory in sortcomplist");
285			bcopy((char )complist,(char )list2,listpos*sizeof(PACKHEAD));
286			qsort((char *)list2, listpos, sizeof(PACKHEAD), beamcmp);
287			mergeclists(complist, list2, listpos,
288			complist+listpos, complen-listpos);
289			free((char *)list2);
290			}
291	gregl	3.2	/* drop satisfied requests */
292	gregl	3.11	for (i = complen; i-- && complist[i].nr <= complist[i].nc; )
293	gregl	3.2	;
294	gregl	3.4	if (i < 0) {
295			free((char *)complist);
296			complist = NULL;
297			complen = 0;
298			} else if (i < complen-1) {
299	gregl	3.2	list2 = (PACKHEAD )realloc((char )complist,
300			(i+1)*sizeof(PACKHEAD));
301			if (list2 != NULL) {
302			complist = list2;
303			complen = i+1;
304			}
305			}
306			listpos = 0; lastin = i;
307	gregl	3.1	}
308
309
310			/*
311			* The following routine works on the assumption that the bundle weights are
312			* more or less evenly distributed, such that computing a packet causes
313			* a given bundle to move way down in the computation order. We keep
314			* track of where the computed bundle with the highest priority would end
315			* up, and if we get further in our compute list than this, we resort the
316	gregl	3.11	* list and start again from the beginning. Since
317			* a merge sort is used, the sorting costs are minimal.
318	gregl	3.1	*/
319			next_packet(p) /* prepare packet for computation */
320			register PACKET *p;
321			{
322			register int i;
323
324	gregl	3.10	if (listpos > lastin) /* time to sort the list */
325			sortcomplist();
326	gregl	3.1	if (complen <= 0)
327			return(0);
328			p->hd = complist[listpos].hd;
329			p->bi = complist[listpos].bi;
330	gregl	3.11	p->nc = complist[listpos].nc;
331			p->nr = complist[listpos].nr - p->nc;
332	gregl	3.1	if (p->nr <= 0)
333			return(0);
334			if (p->nr > RPACKSIZ)
335			p->nr = RPACKSIZ;
336	gregl	3.11	complist[listpos].nc += p->nr; /* find where this one would go */
337			while (lastin > listpos &&
338			beamcmp(complist+lastin, complist+listpos) > 0)
339	gregl	3.1	lastin--;
340			listpos++;
341			return(1);
342			}