src/rt/data.c

/* Copyright (c) 1992 Regents of the University of California */

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

/*
 *  data.c - routines dealing with interpolated data.
 *
 *     6/4/86
 */

#include  "standard.h"

#include  "color.h"

#include  "resolu.h"

#include  "data.h"


#define TABSIZ          97              /* table size (prime) */

#define hash(s)         (shash(s)%TABSIZ)


extern char  *fgetword();

extern char  *libpath;                  /* library search path */

static DATARRAY  *dtab[TABSIZ];         /* data array list */

static DATARRAY  *ptab[TABSIZ];         /* picture list */


DATARRAY *
getdata(dname)                          /* get data array dname */
char  *dname;
{
        char  word[64];
        char  *dfname;
        FILE  *fp;
        int  asize;
        register int  i, j;
        register DATARRAY  *dp;
                                                /* look for array in list */
        for (dp = dtab[hash(dname)]; dp != NULL; dp = dp->next)
                if (!strcmp(dname, dp->name))
                        return(dp);             /* found! */

        /*
         *      If we haven't loaded the data already, we will look
         *  for it in the directories specified by the library path.
         *
         *      The file has the following format:
         *
         *              N
         *              beg0    end0    n0
         *              beg1    end1    n1
         *              . . .
         *              begN    endN    nN
         *              data, later dimensions changing faster
         *              . . .
         *
         *      For irregularly spaced points, the following can be
         *  substituted for begi endi ni:
         *
         *              0 0 ni p0i p1i .. pni
         */

        if ((dfname = getpath(dname, libpath, R_OK)) == NULL) {
                sprintf(errmsg, "cannot find data file \"%s\"", dname);
                error(USER, errmsg);
        }
        if ((dp = (DATARRAY *)malloc(sizeof(DATARRAY))) == NULL)
                goto memerr;

        dp->name = savestr(dname);

        if ((fp = fopen(dfname, "r")) == NULL) {
                sprintf(errmsg, "cannot open data file \"%s\"", dfname);
                error(SYSTEM, errmsg);
        }
                                                        /* get dimensions */
        if (fgetword(word, sizeof(word), fp) == NULL || !isint(word))
                goto scanerr;
        dp->nd = atoi(word);
        if (dp->nd <= 0 || dp->nd > MAXDDIM) {
                sprintf(errmsg, "bad number of dimensions for \"%s\"", dname);
                error(USER, errmsg);
        }
        asize = 1;
        for (i = 0; i < dp->nd; i++) {
                if (fgetword(word, sizeof(word), fp) == NULL || !isflt(word))
                        goto scanerr;
                dp->dim[i].org = atof(word);
                if (fgetword(word, sizeof(word), fp) == NULL || !isflt(word))
                        goto scanerr;
                dp->dim[i].siz = atof(word);
                if (fgetword(word, sizeof(word), fp) == NULL || !isint(word))
                        goto scanerr;
                dp->dim[i].ne = atoi(word);
                if (dp->dim[i].ne < 2)
                        goto scanerr;
                asize *= dp->dim[i].ne;
                if ((dp->dim[i].siz -= dp->dim[i].org) == 0) {
                        dp->dim[i].p = (double *)malloc(dp->dim[i].ne*sizeof(double));
                        if (dp->dim[i].p == NULL)
                                goto memerr;
                        for (j = 0; j < dp->dim[i].ne; j++) {
                                if (fgetword(word, sizeof(word), fp) == NULL ||
                                                !isflt(word))
                                        goto scanerr;
                                dp->dim[i].p[j] = atof(word);
                        }
                        for (j = 1; j < dp->dim[i].ne-1; j++)
                                if ((dp->dim[i].p[j-1] < dp->dim[i].p[j]) !=
                                        (dp->dim[i].p[j] < dp->dim[i].p[j+1]))
                                        goto scanerr;
                        dp->dim[i].org = dp->dim[i].p[0];
                        dp->dim[i].siz = dp->dim[i].p[dp->dim[i].ne-1]
                                                - dp->dim[i].p[0];
                } else
                        dp->dim[i].p = NULL;
        }
        if ((dp->arr = (DATATYPE *)malloc(asize*sizeof(DATATYPE))) == NULL)
                goto memerr;
        
        for (i = 0; i < asize; i++) {
                if (fgetword(word, sizeof(word), fp) == NULL || !isflt(word))
                        goto scanerr;
                dp->arr[i] = atof(word);
        }
        fclose(fp);
        i = hash(dname);
        dp->next = dtab[i];
        return(dtab[i] = dp);

memerr:
        error(SYSTEM, "out of memory in getdata");
scanerr:
        sprintf(errmsg, "%s in data file \"%s\"",
                        feof(fp) ? "unexpected EOF" : "bad format", dfname);
        error(USER, errmsg);
}


static
headaspect(s, iap)                      /* check string for aspect ratio */
char  *s;
double  *iap;
{
        if (isaspect(s))
                *iap *= aspectval(s);
}


DATARRAY *
getpict(pname)                          /* get picture pname */
char  *pname;
{
        extern char  *libpath;
        double  inpaspect;
        char  *pfname;
        FILE  *fp;
        COLOR  *scanin;
        int  sl, ns;
        RESOLU  inpres;
        FLOAT  loc[2];
        int  y;
        register int  x, i;
        register DATARRAY  *pp;
                                                /* look for array in list */
        for (pp = ptab[hash(pname)]; pp != NULL; pp = pp->next)
                if (!strcmp(pname, pp->name))
                        return(pp);             /* found! */

        if ((pfname = getpath(pname, libpath, R_OK)) == NULL) {
                sprintf(errmsg, "cannot find picture file \"%s\"", pname);
                error(USER, errmsg);
        }
        if ((pp = (DATARRAY *)calloc(3, sizeof(DATARRAY))) == NULL)
                goto memerr;

        pp[0].name = 
        pp[1].name =
        pp[2].name = savestr(pname);

        if ((fp = fopen(pfname, "r")) == NULL) {
                sprintf(errmsg, "cannot open picture file \"%s\"", pfname);
                error(SYSTEM, errmsg);
        }
#ifdef MSDOS
        setmode(fileno(fp), O_BINARY);
#endif
                                                /* get dimensions */
        inpaspect = 1.0;
        getheader(fp, headaspect, &inpaspect);
        if (!fgetsresolu(&inpres, fp))
                goto readerr;
        for (i = 0; i < 3; i++) {
                pp[i].nd = 2;
                pp[i].dim[0].ne = inpres.yr;
                pp[i].dim[1].ne = inpres.xr;
                pp[i].dim[0].org =
                pp[i].dim[1].org = 0.0;
                if (inpres.xr <= inpres.yr*inpaspect) {
                        pp[i].dim[0].siz = inpaspect *
                                                (double)inpres.yr/inpres.xr;
                        pp[i].dim[1].siz = 1.0;
                } else {
                        pp[i].dim[0].siz = 1.0;
                        pp[i].dim[1].siz = (double)inpres.xr/inpres.yr /
                                                inpaspect;
                }
                pp[i].dim[0].p = pp[i].dim[1].p = NULL;
                pp[i].arr = (DATATYPE *)
                                malloc(inpres.xr*inpres.yr*sizeof(DATATYPE));
                if (pp[i].arr == NULL)
                        goto memerr;
        }
                                                        /* load picture */
        sl = scanlen(&inpres);
        ns = numscans(&inpres);
        if ((scanin = (COLOR *)malloc(sl*sizeof(COLOR))) == NULL)
                goto memerr;
        for (y = 0; y < ns; y++) {
                if (freadscan(scanin, sl, fp) < 0)
                        goto readerr;
                for (x = 0; x < sl; x++) {
                        pix2loc(loc, &inpres, x, y);
                        i = (int)(loc[1]*inpres.yr)*inpres.xr +
                                        (int)(loc[0]*inpres.xr);
                        pp[0].arr[i] = colval(scanin[x],RED);
                        pp[1].arr[i] = colval(scanin[x],GRN);
                        pp[2].arr[i] = colval(scanin[x],BLU);
                }
        }
        free((char *)scanin);
        fclose(fp);
        i = hash(pname);
        pp[0].next =
        pp[1].next =
        pp[2].next = ptab[i];
        return(ptab[i] = pp);

memerr:
        error(SYSTEM, "out of memory in getpict");
readerr:
        sprintf(errmsg, "bad picture file \"%s\"", pfname);
        error(USER, errmsg);
}


freedata(dname)                 /* free memory associated with dname */
char  *dname;
{
        DATARRAY  head;
        int  hval, nents;
        register DATARRAY  *dp, *dpl;
        register int  i;

        if (dname == NULL) {                    /* free all if NULL */
                hval = 0; nents = TABSIZ;
        } else {
                hval = hash(dname); nents = 1;
        }
        while (nents--) {
                head.next = dtab[hval];
                dpl = &head;
                while ((dp = dpl->next) != NULL)
                        if (dname == NULL || !strcmp(dname, dp->name)) {
                                dpl->next = dp->next;
                                free((char *)dp->arr);
                                for (i = 0; i < dp->nd; i++)
                                        if (dp->dim[i].p != NULL)
                                                free((char *)dp->dim[i].p);
                                freestr(dp->name);
                                free((char *)dp);
                        } else
                                dpl = dp;
                dtab[hval++] = head.next;
        }
}


freepict(pname)                 /* free memory associated with pname */
char  *pname;
{
        DATARRAY  head;
        int  hval, nents;
        register DATARRAY  *pp, *ppl;

        if (pname == NULL) {                    /* free all if NULL */
                hval = 0; nents = TABSIZ;
        } else {
                hval = hash(pname); nents = 1;
        }
        while (nents--) {
                head.next = ptab[hval];
                ppl = &head;
                while ((pp = ppl->next) != NULL)
                        if (pname == NULL || !strcmp(pname, pp->name)) {
                                ppl->next = pp->next;
                                free((char *)pp[0].arr);
                                free((char *)pp[1].arr);
                                free((char *)pp[2].arr);
                                freestr(pp[0].name);
                                free((char *)pp);
                        } else
                                ppl = pp;
                ptab[hval++] = head.next;
        }
}


double
datavalue(dp, pt)               /* interpolate data value at a point */
register DATARRAY  *dp;
double  *pt;
{
        DATARRAY  sd;
        int  asize;
        int  lower, upper;
        register int  i;
        double  x, y, y0, y1;
                                        /* set up dimensions for recursion */
        sd.nd = dp->nd - 1;
        asize = 1;
        for (i = 0; i < sd.nd; i++) {
                sd.dim[i].org = dp->dim[i+1].org;
                sd.dim[i].siz = dp->dim[i+1].siz;
                sd.dim[i].p = dp->dim[i+1].p;
                asize *= sd.dim[i].ne = dp->dim[i+1].ne;
        }
                                        /* get independent variable */
        if (dp->dim[0].p == NULL) {             /* evenly spaced points */
                x = (pt[0] - dp->dim[0].org)/dp->dim[0].siz;
                x = x * (dp->dim[0].ne - 1);
                i = x;
                if (i < 0)
                        i = 0;
                else if (i > dp->dim[0].ne - 2)
                        i = dp->dim[0].ne - 2;
        } else {                                /* unevenly spaced points */
                if (dp->dim[0].siz > 0.0) {
                        lower = 0;
                        upper = dp->dim[0].ne;
                } else {
                        lower = dp->dim[0].ne;
                        upper = 0;
                }
                do {
                        i = (lower + upper) >> 1;
                        if (pt[0] >= dp->dim[0].p[i])
                                lower = i;
                        else
                                upper = i;
                } while (i != (lower + upper) >> 1);
                if (i > dp->dim[0].ne - 2)
                        i = dp->dim[0].ne - 2;
                x = i + (pt[0] - dp->dim[0].p[i]) /
                                (dp->dim[0].p[i+1] - dp->dim[0].p[i]);
        }
                                        /* get dependent variable */
        if (dp->nd == 1) {
                y0 = dp->arr[i];
                y1 = dp->arr[i+1];
        } else {
                sd.arr = &dp->arr[i*asize];
                y0 = datavalue(&sd, pt+1);
                sd.arr = &dp->arr[(i+1)*asize];
                y1 = datavalue(&sd, pt+1);
        }
        /*
         * Extrapolate as far as one division, then
         * taper off harmonically to zero.
         */
        if (x > i+2)
                y = (2*y1-y0)/(x-i-1);
        else if (x < i-1)
                y = (2*y0-y1)/(i-x);
        else
                y = y0*((i+1)-x) + y1*(x-i);

        return(y);
}
Revision:	2.6
Committed:	Sun Nov 22 10:47:51 1992 UTC (31 years, 5 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.5:	+58 -35 lines
Log Message:	finally moved to hash-table lookup of data file entries
#	User	Rev	Content
1	greg	2.3	/* Copyright (c) 1992 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* data.c - routines dealing with interpolated data.
9			*
10			* 6/4/86
11			*/
12
13			#include "standard.h"
14
15			#include "color.h"
16
17	greg	1.11	#include "resolu.h"
18
19	greg	1.1	#include "data.h"
20
21
22	greg	2.6	#define TABSIZ 97 /* table size (prime) */
23
24			#define hash(s) (shash(s)%TABSIZ)
25
26
27	greg	1.10	extern char *fgetword();
28
29	greg	1.1	extern char libpath; / library search path */
30
31	greg	2.6	static DATARRAY dtab[TABSIZ]; / data array list */
32	greg	1.1
33	greg	2.6	static DATARRAY ptab[TABSIZ]; / picture list */
34	greg	1.1
35
36			DATARRAY *
37			getdata(dname) /* get data array dname */
38			char *dname;
39			{
40	greg	1.10	char word[64];
41	greg	1.1	char *dfname;
42			FILE *fp;
43			int asize;
44	greg	1.4	register int i, j;
45	greg	1.1	register DATARRAY *dp;
46			/* look for array in list */
47	greg	2.6	for (dp = dtab[hash(dname)]; dp != NULL; dp = dp->next)
48	greg	1.1	if (!strcmp(dname, dp->name))
49			return(dp); /* found! */
50
51			/*
52			* If we haven't loaded the data already, we will look
53	greg	2.5	* for it in the directories specified by the library path.
54	greg	1.1	*
55			* The file has the following format:
56			*
57	greg	1.4	* N
58	greg	1.1	* beg0 end0 n0
59			* beg1 end1 n1
60			* . . .
61	greg	1.4	* begN endN nN
62	greg	1.1	* data, later dimensions changing faster
63			* . . .
64			*
65	greg	1.4	* For irregularly spaced points, the following can be
66			* substituted for begi endi ni:
67			*
68	greg	1.6	* 0 0 ni p0i p1i .. pni
69	greg	1.1	*/
70
71	greg	1.2	if ((dfname = getpath(dname, libpath, R_OK)) == NULL) {
72	greg	1.1	sprintf(errmsg, "cannot find data file \"%s\"", dname);
73			error(USER, errmsg);
74			}
75			if ((dp = (DATARRAY *)malloc(sizeof(DATARRAY))) == NULL)
76			goto memerr;
77
78			dp->name = savestr(dname);
79
80			if ((fp = fopen(dfname, "r")) == NULL) {
81			sprintf(errmsg, "cannot open data file \"%s\"", dfname);
82			error(SYSTEM, errmsg);
83			}
84			/* get dimensions */
85	greg	1.10	if (fgetword(word, sizeof(word), fp) == NULL \|\| !isint(word))
86	greg	1.1	goto scanerr;
87	greg	1.10	dp->nd = atoi(word);
88	greg	1.9	if (dp->nd <= 0 \|\| dp->nd > MAXDDIM) {
89	greg	1.1	sprintf(errmsg, "bad number of dimensions for \"%s\"", dname);
90			error(USER, errmsg);
91			}
92			asize = 1;
93			for (i = 0; i < dp->nd; i++) {
94	greg	1.10	if (fgetword(word, sizeof(word), fp) == NULL \|\| !isflt(word))
95	greg	1.6	goto scanerr;
96	greg	1.10	dp->dim[i].org = atof(word);
97			if (fgetword(word, sizeof(word), fp) == NULL \|\| !isflt(word))
98			goto scanerr;
99			dp->dim[i].siz = atof(word);
100			if (fgetword(word, sizeof(word), fp) == NULL \|\| !isint(word))
101			goto scanerr;
102			dp->dim[i].ne = atoi(word);
103	greg	1.6	if (dp->dim[i].ne < 2)
104			goto scanerr;
105			asize *= dp->dim[i].ne;
106			if ((dp->dim[i].siz -= dp->dim[i].org) == 0) {
107	greg	1.4	dp->dim[i].p = (double )malloc(dp->dim[i].nesizeof(double));
108			if (dp->dim[i].p == NULL)
109			goto memerr;
110	greg	1.10	for (j = 0; j < dp->dim[i].ne; j++) {
111			if (fgetword(word, sizeof(word), fp) == NULL \|\|
112			!isflt(word))
113	greg	1.4	goto scanerr;
114	greg	1.10	dp->dim[i].p[j] = atof(word);
115			}
116	greg	1.4	for (j = 1; j < dp->dim[i].ne-1; j++)
117			if ((dp->dim[i].p[j-1] < dp->dim[i].p[j]) !=
118			(dp->dim[i].p[j] < dp->dim[i].p[j+1]))
119			goto scanerr;
120			dp->dim[i].org = dp->dim[i].p[0];
121			dp->dim[i].siz = dp->dim[i].p[dp->dim[i].ne-1]
122			- dp->dim[i].p[0];
123			} else
124	greg	1.6	dp->dim[i].p = NULL;
125	greg	1.1	}
126			if ((dp->arr = (DATATYPE )malloc(asizesizeof(DATATYPE))) == NULL)
127			goto memerr;
128
129	greg	1.10	for (i = 0; i < asize; i++) {
130			if (fgetword(word, sizeof(word), fp) == NULL \|\| !isflt(word))
131	greg	1.1	goto scanerr;
132	greg	1.10	dp->arr[i] = atof(word);
133			}
134	greg	1.1	fclose(fp);
135	greg	2.6	i = hash(dname);
136			dp->next = dtab[i];
137			return(dtab[i] = dp);
138	greg	1.1
139			memerr:
140			error(SYSTEM, "out of memory in getdata");
141			scanerr:
142			sprintf(errmsg, "%s in data file \"%s\"",
143			feof(fp) ? "unexpected EOF" : "bad format", dfname);
144			error(USER, errmsg);
145			}
146
147
148	greg	1.5	static
149	greg	2.4	headaspect(s, iap) /* check string for aspect ratio */
150	greg	1.5	char *s;
151	greg	2.4	double *iap;
152	greg	1.5	{
153			if (isaspect(s))
154	greg	2.4	iap = aspectval(s);
155	greg	1.5	}
156
157
158	greg	1.1	DATARRAY *
159			getpict(pname) /* get picture pname */
160			char *pname;
161			{
162			extern char *libpath;
163	greg	2.4	double inpaspect;
164	greg	1.1	char *pfname;
165			FILE *fp;
166			COLOR *scanin;
167	greg	1.11	int sl, ns;
168	greg	2.3	RESOLU inpres;
169	greg	1.11	FLOAT loc[2];
170			int y;
171			register int x, i;
172	greg	1.1	register DATARRAY *pp;
173			/* look for array in list */
174	greg	2.6	for (pp = ptab[hash(pname)]; pp != NULL; pp = pp->next)
175	greg	1.1	if (!strcmp(pname, pp->name))
176			return(pp); /* found! */
177
178	greg	1.2	if ((pfname = getpath(pname, libpath, R_OK)) == NULL) {
179	greg	1.1	sprintf(errmsg, "cannot find picture file \"%s\"", pname);
180			error(USER, errmsg);
181			}
182			if ((pp = (DATARRAY *)calloc(3, sizeof(DATARRAY))) == NULL)
183			goto memerr;
184
185			pp[0].name =
186			pp[1].name =
187			pp[2].name = savestr(pname);
188
189			if ((fp = fopen(pfname, "r")) == NULL) {
190			sprintf(errmsg, "cannot open picture file \"%s\"", pfname);
191			error(SYSTEM, errmsg);
192			}
193	greg	2.3	#ifdef MSDOS
194			setmode(fileno(fp), O_BINARY);
195			#endif
196	greg	1.1	/* get dimensions */
197	greg	1.5	inpaspect = 1.0;
198	greg	2.4	getheader(fp, headaspect, &inpaspect);
199	greg	1.11	if (!fgetsresolu(&inpres, fp))
200	greg	1.1	goto readerr;
201			for (i = 0; i < 3; i++) {
202			pp[i].nd = 2;
203	greg	1.11	pp[i].dim[0].ne = inpres.yr;
204			pp[i].dim[1].ne = inpres.xr;
205	greg	1.1	pp[i].dim[0].org =
206			pp[i].dim[1].org = 0.0;
207	greg	1.11	if (inpres.xr <= inpres.yr*inpaspect) {
208			pp[i].dim[0].siz = inpaspect *
209			(double)inpres.yr/inpres.xr;
210	greg	1.7	pp[i].dim[1].siz = 1.0;
211			} else {
212	greg	1.1	pp[i].dim[0].siz = 1.0;
213	greg	1.11	pp[i].dim[1].siz = (double)inpres.xr/inpres.yr /
214			inpaspect;
215	greg	1.1	}
216	greg	1.7	pp[i].dim[0].p = pp[i].dim[1].p = NULL;
217	greg	1.11	pp[i].arr = (DATATYPE *)
218			malloc(inpres.xrinpres.yrsizeof(DATATYPE));
219	greg	1.1	if (pp[i].arr == NULL)
220			goto memerr;
221			}
222			/* load picture */
223	greg	1.11	sl = scanlen(&inpres);
224			ns = numscans(&inpres);
225			if ((scanin = (COLOR )malloc(slsizeof(COLOR))) == NULL)
226	greg	1.1	goto memerr;
227	greg	1.11	for (y = 0; y < ns; y++) {
228			if (freadscan(scanin, sl, fp) < 0)
229	greg	1.1	goto readerr;
230	greg	1.11	for (x = 0; x < sl; x++) {
231			pix2loc(loc, &inpres, x, y);
232			i = (int)(loc[1]inpres.yr)inpres.xr +
233			(int)(loc[0]*inpres.xr);
234			pp[0].arr[i] = colval(scanin[x],RED);
235			pp[1].arr[i] = colval(scanin[x],GRN);
236			pp[2].arr[i] = colval(scanin[x],BLU);
237			}
238	greg	1.1	}
239			free((char *)scanin);
240			fclose(fp);
241	greg	2.6	i = hash(pname);
242	greg	1.1	pp[0].next =
243			pp[1].next =
244	greg	2.6	pp[2].next = ptab[i];
245			return(ptab[i] = pp);
246	greg	1.1
247			memerr:
248			error(SYSTEM, "out of memory in getpict");
249			readerr:
250			sprintf(errmsg, "bad picture file \"%s\"", pfname);
251			error(USER, errmsg);
252			}
253
254
255			freedata(dname) /* free memory associated with dname */
256			char *dname;
257			{
258	greg	2.5	DATARRAY head;
259	greg	2.6	int hval, nents;
260	greg	1.1	register DATARRAY dp, dpl;
261	greg	1.4	register int i;
262	greg	1.1
263	greg	2.6	if (dname == NULL) { /* free all if NULL */
264			hval = 0; nents = TABSIZ;
265			} else {
266			hval = hash(dname); nents = 1;
267			}
268			while (nents--) {
269			head.next = dtab[hval];
270			dpl = &head;
271			while ((dp = dpl->next) != NULL)
272			if (dname == NULL \|\| !strcmp(dname, dp->name)) {
273			dpl->next = dp->next;
274			free((char *)dp->arr);
275			for (i = 0; i < dp->nd; i++)
276			if (dp->dim[i].p != NULL)
277			free((char *)dp->dim[i].p);
278			freestr(dp->name);
279			free((char *)dp);
280			} else
281			dpl = dp;
282			dtab[hval++] = head.next;
283			}
284	greg	1.1	}
285
286
287			freepict(pname) /* free memory associated with pname */
288			char *pname;
289			{
290	greg	2.5	DATARRAY head;
291	greg	2.6	int hval, nents;
292	greg	1.1	register DATARRAY pp, ppl;
293
294	greg	2.6	if (pname == NULL) { /* free all if NULL */
295			hval = 0; nents = TABSIZ;
296			} else {
297			hval = hash(pname); nents = 1;
298			}
299			while (nents--) {
300			head.next = ptab[hval];
301			ppl = &head;
302			while ((pp = ppl->next) != NULL)
303			if (pname == NULL \|\| !strcmp(pname, pp->name)) {
304			ppl->next = pp->next;
305			free((char *)pp[0].arr);
306			free((char *)pp[1].arr);
307			free((char *)pp[2].arr);
308			freestr(pp[0].name);
309			free((char *)pp);
310			} else
311			ppl = pp;
312			ptab[hval++] = head.next;
313			}
314	greg	1.1	}
315
316
317			double
318			datavalue(dp, pt) /* interpolate data value at a point */
319			register DATARRAY *dp;
320	greg	2.3	double *pt;
321	greg	1.1	{
322			DATARRAY sd;
323			int asize;
324	greg	1.6	int lower, upper;
325	greg	1.1	register int i;
326	greg	2.3	double x, y, y0, y1;
327	greg	1.4	/* set up dimensions for recursion */
328	greg	1.1	sd.nd = dp->nd - 1;
329			asize = 1;
330			for (i = 0; i < sd.nd; i++) {
331			sd.dim[i].org = dp->dim[i+1].org;
332			sd.dim[i].siz = dp->dim[i+1].siz;
333	greg	1.4	sd.dim[i].p = dp->dim[i+1].p;
334	greg	1.1	asize *= sd.dim[i].ne = dp->dim[i+1].ne;
335			}
336	greg	1.4	/* get independent variable */
337			if (dp->dim[0].p == NULL) { /* evenly spaced points */
338			x = (pt[0] - dp->dim[0].org)/dp->dim[0].siz;
339			x = x * (dp->dim[0].ne - 1);
340			i = x;
341			if (i < 0)
342			i = 0;
343			else if (i > dp->dim[0].ne - 2)
344			i = dp->dim[0].ne - 2;
345			} else { /* unevenly spaced points */
346	greg	1.6	if (dp->dim[0].siz > 0.0) {
347			lower = 0;
348			upper = dp->dim[0].ne;
349			} else {
350			lower = dp->dim[0].ne;
351			upper = 0;
352			}
353			do {
354			i = (lower + upper) >> 1;
355			if (pt[0] >= dp->dim[0].p[i])
356			lower = i;
357	greg	1.8	else
358	greg	1.6	upper = i;
359			} while (i != (lower + upper) >> 1);
360	greg	1.8	if (i > dp->dim[0].ne - 2)
361	greg	1.4	i = dp->dim[0].ne - 2;
362			x = i + (pt[0] - dp->dim[0].p[i]) /
363			(dp->dim[0].p[i+1] - dp->dim[0].p[i]);
364			}
365			/* get dependent variable */
366	greg	1.1	if (dp->nd == 1) {
367			y0 = dp->arr[i];
368			y1 = dp->arr[i+1];
369			} else {
370			sd.arr = &dp->arr[i*asize];
371			y0 = datavalue(&sd, pt+1);
372			sd.arr = &dp->arr[(i+1)*asize];
373			y1 = datavalue(&sd, pt+1);
374			}
375			/*
376			* Extrapolate as far as one division, then
377			* taper off harmonically to zero.
378			*/
379			if (x > i+2)
380			y = (2*y1-y0)/(x-i-1);
381			else if (x < i-1)
382			y = (2*y0-y1)/(i-x);
383			else
384			y = y0((i+1)-x) + y1(x-i);
385
386			return(y);
387			}