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| -rw-r--r-- | toys/cal.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/toys/cal.c b/toys/cal.c new file mode 100644 index 00000000..1c018e2f --- /dev/null +++ b/toys/cal.c @@ -0,0 +1,134 @@ +/* vi: set sw=4 ts=4: + * + * cal.c - show calendar. + * + * Copyright 2011 Rob Landley <rob@landley.net> + * + * See http://opengroup.org/onlinepubs/9699919799/utilities/cal.html + +USE_CAL(NEWTOY(cal, ">2", TOYFLAG_USR|TOYFLAG_BIN)) + +config CAL + bool "cal" + default y + help + usage: cal [[month] year] + Print a calendar. + + With one argument, prints all months of the specified year. + With two arguments, prints calendar for month and year. +*/ + +#include "toys.h" + +// Write calendar into buffer: each line is 20 chars wide, end indicated +// by empty string. + +static char *calstrings(char *buf, struct tm *tm) +{ + char temp[21]; + int wday, mday, start, len, line; + + // header + len = strftime(temp, 21, "%B %Y", tm); + len += (20-len)/2; + buf += sprintf(buf, "%*s%*s ", len, temp, 20-len, ""); + buf++; + buf += sprintf(buf, "Su Mo Tu We Th Fr Sa "); + buf++; + + // What day of the week does this month start on? + if (tm->tm_mday>1) + start = (36+tm->tm_wday-tm->tm_mday)%7; + else start = tm->tm_wday; + + // What day does this month end on? Alas, libc doesn't tell us... + len = 31; + if (tm->tm_mon == 1) { + int year = tm->tm_year; + len = 28; + if (!(year & 3) && !((year&100) && !(year&400))) len++; + } else if ((tm->tm_mon+(tm->tm_mon>6 ? 1 : 0)) & 1) len = 30; + + for (mday=line=0;line<6;line++) { + for (wday=0; wday<7; wday++) { + char *pat = " "; + if (!mday ? wday==start : mday<len) { + pat = "%2d "; + mday++; + } + buf += sprintf(buf, pat, mday); + } + buf++; + } + + return buf; +} + +void xcheckrange(long val, long low, long high) +{ + char *err = "%ld %s than %ld"; + + if (val < low) error_exit(err, val, "less", low); + if (val > high) error_exit(err, val, "greater", high); +} + +// Worst case scenario toybuf usage: sizeof(struct tm) plus 21 bytes/line +// plus 8 lines/month plus 12 months, comes to a bit over 2k of our 4k buffer. + +void cal_main(void) +{ + struct tm *tm; + char *buf = toybuf; + + if (toys.optc) { + // Conveniently starts zeroed + tm = (struct tm *)toybuf; + buf += sizeof(struct tm); + + // Last argument is year, one before that (if any) is month. + xcheckrange(tm->tm_year = atol(toys.optargs[--toys.optc]),1,9999); + tm->tm_year -= 1900; + tm->tm_mday = 1; + tm->tm_hour = 12; // noon to avoid timezone weirdness + if (toys.optc) { + xcheckrange(tm->tm_mon = atol(toys.optargs[--toys.optc]),1,12); + tm->tm_mon--; + + // Print 12 months of the year + + } else { + char *bufs[12]; + int i, j, k; + + for (i=0; i<12; i++) { + tm->tm_mon=i; + mktime(tm); + buf = calstrings(bufs[i]=buf, tm); + } + + // 4 rows, 6 lines each, 3 columns + for (i=0; i<4; i++) { + for (j=0; j<8; j++) { + for(k=0; k<3; k++) { + char **b = bufs+(k+i*3); + *b += printf("%s ", *b); + } + puts(""); + } + } + return; + } + + // What day of the week does that start on? + mktime(tm); + + } else { + time_t now; + time(&now); + tm = localtime(&now); + } + + calstrings(buf, tm); + while (*buf) buf += printf("%s\n", buf); +} |