1 /* ti.c: classify line intersections */
2 # include "t.h"
3 /* determine local environment for intersections */
4 
5 int
6 interv(int i, int c)
7 {
8 	int	ku, kl;
9 
10 	if (c >= ncol || c == 0) {
11 		if (dboxflg) {
12 			if (i == 0) 
13 				return(BOT);
14 			if (i >= nlin) 
15 				return(TOP);
16 			return(THRU);
17 		}
18 		if (c >= ncol)
19 			return(0);
20 	}
21 	ku = i > 0 ? lefdata(i - 1, c) : 0;
22 	if (i + 1 >= nlin && allh(i))
23 		kl = 0;
24 	else
25 		kl = lefdata(allh(i) ? i + 1 : i, c);
26 	if (ku == 2 && kl == 2) 
27 		return(THRU);
28 	if (ku == 2) 
29 		return(TOP);
30 	if (kl == BOT) 
31 		return(2);
32 	return(0);
33 }
34 
35 
36 int
37 interh(int i, int c)
38 {
39 	int	kl, kr;
40 
41 	if (fullbot[i] == '=' || (dboxflg && (i == 0 || i >= nlin - 1))) {
42 		if (c == ncol)
43 			return(LEFT);
44 		if (c == 0)
45 			return(RIGHT);
46 		return(THRU);
47 	}
48 	if (i >= nlin) 
49 		return(0);
50 	kl = c > 0 ? thish (i, c - 1) : 0;
51 	if (kl <= 1 && i > 0 && allh(up1(i)))
52 		kl = c > 0 ? thish(up1(i), c - 1) : 0;
53 	kr = thish(i, c);
54 	if (kr <= 1 && i > 0 && allh(up1(i)))
55 		kr = c > 0 ? thish(up1(i), c) : 0;
56 	if (kl == '=' && kr ==  '=') 
57 		return(THRU);
58 	if (kl == '=') 
59 		return(LEFT);
60 	if (kr == '=') 
61 		return(RIGHT);
62 	return(0);
63 }
64 
65 
66 int
67 up1(int i)
68 {
69 	i--;
70 	while (instead[i] && i > 0) 
71 		i--;
72 	return(i);
73 }
74 
75