1 /* cal.c - show calendar.
2 *
3 * Copyright 2011 Rob Landley <rob@landley.net>
4 *
5 * See http://opengroup.org/onlinepubs/9699919799/utilities/cal.html
6
7 USE_CAL(NEWTOY(cal, ">2h", TOYFLAG_USR|TOYFLAG_BIN))
8
9 config CAL
10 bool "cal"
11 default y
12 help
13 usage: cal [[MONTH] YEAR]
14
15 Print a calendar.
16
17 With one argument, prints all months of the specified year.
18 With two arguments, prints calendar for month and year.
19
20 -h Don't highlight today
21 */
22
23 #define FOR_cal
24 #include "toys.h"
25
GLOBALS(struct tm * now;)26 GLOBALS(
27 struct tm *now;
28 )
29
30 // Write calendar into buffer: each line is 20 chars wide, end indicated
31 // by empty string.
32
33 static char *calstrings(char *buf, struct tm *tm)
34 {
35 char temp[21];
36 int wday, mday, start, len, line;
37
38 // header
39 len = strftime(temp, 21, "%B %Y", tm);
40 len += (20-len)/2;
41 buf += sprintf(buf, "%*s%*s ", len, temp, 20-len, "");
42 buf++;
43 buf += sprintf(buf, "Su Mo Tu We Th Fr Sa ");
44 buf++;
45
46 // What day of the week does this month start on?
47 if (tm->tm_mday>1)
48 start = (36+tm->tm_wday-tm->tm_mday)%7;
49 else start = tm->tm_wday;
50
51 // What day does this month end on? Alas, libc doesn't tell us...
52 len = 31;
53 if (tm->tm_mon == 1) {
54 int year = tm->tm_year;
55 len = 28;
56 if (!(year & 3) && !((year&100) && !(year&400))) len++;
57 } else if ((tm->tm_mon+(tm->tm_mon>6 ? 1 : 0)) & 1) len = 30;
58
59 for (mday=line=0;line<6;line++) {
60 for (wday=0; wday<7; wday++) {
61 char *pat = " ";
62 if (!mday ? wday==start : mday<len) {
63 pat = "%2d ";
64 if (!FLAG(h) && tm->tm_year == TT.now->tm_year &&
65 tm->tm_mon == TT.now->tm_mon && mday == TT.now->tm_mday-1) {
66 pat = "\x1b[7m%2d\x1b[m ";
67 }
68 mday++;
69 }
70 buf += sprintf(buf, pat, mday);
71 }
72 buf++;
73 }
74
75 return buf;
76 }
77
78 // Worst case scenario toybuf usage: sizeof(struct tm) plus 21 bytes/line
79 // plus 8 lines/month plus 12 months, plus the escape sequences to highlight
80 // today comes to a bit over 2k of our 4k buffer.
81
cal_main(void)82 void cal_main(void)
83 {
84 time_t now = time(0);
85 struct tm *tm = localtime(&now);
86 char *buf = toybuf;
87
88 TT.now = tm;
89 if (!isatty(1)) toys.optflags |= FLAG_h;
90
91 if (toys.optc) {
92 // Conveniently starts zeroed
93 tm = (struct tm *)toybuf;
94 buf += sizeof(struct tm);
95
96 // Last argument is year, one before that (if any) is month.
97 tm->tm_year = atolx_range(toys.optargs[--toys.optc], 1, 9999);
98 tm->tm_year -= 1900;
99 tm->tm_mday = 1;
100 tm->tm_hour = 12; // noon to avoid timezone weirdness
101 if (toys.optc) {
102 tm->tm_mon = atolx_range(toys.optargs[--toys.optc], 1, 12);
103 tm->tm_mon--;
104
105 // Print 12 months of the year
106
107 } else {
108 char *bufs[12];
109 int i, j, k;
110
111 for (i=0; i<12; i++) {
112 tm->tm_mon=i;
113 mktime(tm);
114 buf = calstrings(bufs[i]=buf, tm);
115 }
116
117 // 4 rows, 6 lines each, 3 columns
118 for (i=0; i<4; i++) {
119 for (j=0; j<8; j++) {
120 for(k=0; k<3; k++) {
121 char **b = bufs+(k+i*3);
122 *b += printf("%s ", *b);
123 }
124 puts("");
125 }
126 }
127 return;
128 }
129
130 // What day of the week does that start on?
131 mktime(tm);
132 }
133
134 calstrings(buf, tm);
135 while (*buf) buf += printf("%s\n", buf);
136 }
137