1 #include <u.h>
2 #include <libc.h>
3 
4 double	min = 1.0;
5 double	max = 0.0;
6 double	incr = 1.0;
7 int	constant = 0;
8 int	nsteps;
9 char	*format;
10 
11 void
12 usage(void)
13 {
14 	fprint(2, "usage: seq [-fformat] [-w] [first [incr]] last\n");
15 	exits("usage");
16 }
17 
18 void
19 buildfmt(void)
20 {
21 	char *dp;
22 	int w, p, maxw, maxp;
23 	static char fmt[16];
24 	char buf[32];
25 	double val;
26 
27 	format = "%g\n";
28 	if(!constant)
29 		return;
30 	maxw = 0;
31 	maxp = 0;
32 	for(val = min; val <= max; val += incr){
33 		sprint(buf, "%g", val);
34 		if(strchr(buf, 'e')!=0)
35 			return;
36 		dp = strchr(buf,'.');
37 		w = dp==0? strlen(buf): dp-buf;
38 		p = dp==0? 0: strlen(strchr(buf,'.')+1);
39 		if(w>maxw)
40 			maxw = w;
41 		if(p>maxp)
42 			maxp = p;
43 	}
44 	if(maxp > 0)
45 		maxw += maxp+1;
46 	sprint(fmt,"%%%d.%df\n", maxw, maxp);
47 	format = fmt;
48 }
49 
50 void
51 main(int argc, char *argv[]){
52 	int j, n;
53 	char buf[256], ffmt[4096];
54 	double val;
55 
56 	ARGBEGIN{
57 	case 'w':
58 		constant++;
59 		break;
60 	case 'f':
61 		format = ARGF();
62 		if(format[strlen(format)-1] != '\n'){
63 			sprint(ffmt, "%s\n", format);
64 			format = ffmt;
65 		}
66 		break;
67 	default:
68 		goto out;
69 	}ARGEND
70     out:
71 	if(argc<1 || argc>3)
72 		usage();
73 	max = atof(argv[argc-1]);
74 	if(argc > 1)
75 		min = atof(argv[0]);
76 	if(argc > 2)
77 		incr = atof(argv[1]);
78 	if(incr == 0){
79 		fprint(2, "seq: zero increment\n");
80 		exits("zero increment");
81 	}
82 	if(!format)
83 		buildfmt();
84 	if(incr > 0){
85 		for(val = min; val <= max; val += incr){
86 			n = sprint(buf, format, val);
87 			if(constant)
88 				for(j=0; buf[j]==' '; j++)
89 					buf[j] ='0';
90 			write(1, buf, n);
91 		}
92 	}else{
93 		for(val = min; val >= max; val += incr){
94 			n = sprint(buf, format, val);
95 			if(constant)
96 				for(j=0; buf[j]==' '; j++)
97 					buf[j] ='0';
98 			write(1, buf, n);
99 		}
100 	}
101 	exits(0);
102 }