diff options
Diffstat (limited to 'util/sbase/cal.c')
| -rw-r--r-- | util/sbase/cal.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/util/sbase/cal.c b/util/sbase/cal.c new file mode 100644 index 00000000..a8c91f19 --- /dev/null +++ b/util/sbase/cal.c @@ -0,0 +1,226 @@ +/* See LICENSE file for copyright and license details. */ +#include <limits.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <time.h> +#include <unistd.h> + +#include "util.h" + +enum { JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC }; +enum caltype { JULIAN, GREGORIAN }; +enum { TRANS_YEAR = 1752, TRANS_MONTH = SEP, TRANS_DAY = 2 }; + +static struct tm *ltime; + +static int +isleap(size_t year, enum caltype cal) +{ + if (cal == GREGORIAN) { + if (year % 400 == 0) + return 1; + if (year % 100 == 0) + return 0; + return (year % 4 == 0); + } + else { /* cal == Julian */ + return (year % 4 == 0); + } +} + +static int +monthlength(size_t year, int month, enum caltype cal) +{ + int mdays[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; + + return (month == FEB && isleap(year, cal)) ? 29 : mdays[month]; +} + +/* From http://www.tondering.dk/claus/cal/chrweek.php#calcdow */ +static int +dayofweek(size_t year, int month, int dom, enum caltype cal) +{ + size_t y; + int m, a; + + a = (13 - month) / 12; + y = year - a; + m = month + 12 * a - 1; + + if (cal == GREGORIAN) + return (dom + y + y / 4 - y / 100 + y / 400 + (31 * m) / 12) % 7; + else /* cal == Julian */ + return (5 + dom + y + y / 4 + (31 * m) / 12) % 7; +} + +static void +printgrid(size_t year, int month, int fday, int line) +{ + enum caltype cal; + int offset, dom, d = 0, trans; /* are we in the transition from Julian to Gregorian? */ + int today = 0; + + cal = (year < TRANS_YEAR || (year == TRANS_YEAR && month <= TRANS_MONTH)) ? JULIAN : GREGORIAN; + trans = (year == TRANS_YEAR && month == TRANS_MONTH); + offset = dayofweek(year, month, 1, cal) - fday; + + if (offset < 0) + offset += 7; + if (line == 1) { + for (; d < offset; ++d) + printf(" "); + dom = 1; + } else { + dom = 8 - offset + (line - 2) * 7; + if (trans && !(line == 2 && fday == 3)) + dom += 11; + } + if (ltime && year == ltime->tm_year + 1900 && month == ltime->tm_mon) + today = ltime->tm_mday; + for (; d < 7 && dom <= monthlength(year, month, cal); ++d, ++dom) { + if (dom == today) + printf("\x1b[7m%2d\x1b[0m ", dom); /* highlight today's date */ + else + printf("%2d ", dom); + if (trans && dom == TRANS_DAY) + dom += 11; + } + for (; d < 7; ++d) + printf(" "); +} + +static void +drawcal(size_t year, int month, size_t ncols, size_t nmons, int fday) +{ + char *smon[] = { "January", "February", "March", "April", + "May", "June", "July", "August", + "September", "October", "November", "December" }; + char *days[] = { "Su", "Mo", "Tu", "We", "Th", "Fr", "Sa", }; + size_t m, n, col, cur_year, cur_month, dow; + int line, pad; + char month_year[sizeof("Su Mo Tu We Th Fr Sa")]; + + for (m = 0; m < nmons; ) { + n = m; + for (col = 0; m < nmons && col < ncols; ++col, ++m) { + cur_year = year + m / 12; + cur_month = month + m % 12; + if (cur_month > 11) { + cur_month -= 12; + cur_year += 1; + } + snprintf(month_year, sizeof(month_year), "%s %zu", smon[cur_month], cur_year); + pad = sizeof(month_year) - 1 - strlen(month_year); + printf("%*s%s%*s ", pad / 2 + pad % 2, "", month_year, pad / 2, ""); + } + putchar('\n'); + for (col = 0, m = n; m < nmons && col < ncols; ++col, ++m) { + for (dow = fday; dow < (fday + 7); ++dow) + printf("%s ", days[dow % 7]); + printf(" "); + } + putchar('\n'); + for (line = 1; line <= 6; ++line) { + for (col = 0, m = n; m < nmons && col < ncols; ++col, ++m) { + cur_year = year + m / 12; + cur_month = month + m % 12; + if (cur_month > 11) { + cur_month -= 12; + cur_year += 1; + } + printgrid(cur_year, cur_month, fday, line); + printf(" "); + } + putchar('\n'); + } + } +} + +static void +usage(void) +{ + eprintf("usage: %s [-1 | -3 | -y | -n num] " + "[-s | -m | -f num] [-c num] [[month] year]\n", argv0); +} + +int +main(int argc, char *argv[]) +{ + time_t now; + size_t year, ncols, nmons; + int fday, month; + + now = time(NULL); + ltime = localtime(&now); + year = ltime->tm_year + 1900; + month = ltime->tm_mon + 1; + fday = 0; + + if (!isatty(STDOUT_FILENO)) + ltime = NULL; /* don't highlight today's date */ + + ncols = 3; + nmons = 0; + + ARGBEGIN { + case '1': + nmons = 1; + break; + case '3': + nmons = 3; + if (--month == 0) { + month = 12; + year--; + } + break; + case 'c': + ncols = estrtonum(EARGF(usage()), 0, MIN(SIZE_MAX, LLONG_MAX)); + break; + case 'f': + fday = estrtonum(EARGF(usage()), 0, 6); + break; + case 'm': /* Monday */ + fday = 1; + break; + case 'n': + nmons = estrtonum(EARGF(usage()), 1, MIN(SIZE_MAX, LLONG_MAX)); + break; + case 's': /* Sunday */ + fday = 0; + break; + case 'y': + month = 1; + nmons = 12; + break; + default: + usage(); + } ARGEND + + if (nmons == 0) { + if (argc == 1) { + month = 1; + nmons = 12; + } else { + nmons = 1; + } + } + + switch (argc) { + case 2: + month = estrtonum(argv[0], 1, 12); + argv++; + case 1: /* fallthrough */ + year = estrtonum(argv[0], 0, INT_MAX); + break; + case 0: + break; + default: + usage(); + } + + drawcal(year, month - 1, ncols, nmons, fday); + + return fshut(stdout, "<stdout>"); +} |