cal: fix julian calendars for large years

[thirdparty/util-linux.git] / misc-utils / cal.c

diff --git a/misc-utils/cal.c b/misc-utils/cal.c
index ea582964c219ac6d9700eb5b244e017b6f08219f..a854eaf9d073382d277bce99ea608746eeb0d064 100644 (file)
--- a/misc-utils/cal.c
+++ b/misc-utils/cal.c
@@ -133,6 +133,14 @@ static const char *my_tgetstr(char *ss
 
 #include "widechar.h"
 
+enum {
+       GREGORIAN               = INT32_MIN,
+       ISO                     = INT32_MIN,
+       GB1752                  = 1752,
+       DEFAULT_REFORM_YEAR     = 1752,
+       JULIAN                  = INT32_MAX
+};
+
 enum {
        SUNDAY = 0,
        MONDAY,
@@ -246,6 +254,7 @@ static int week_number(int day, int month, int32_t year, const struct cal_contro
 static int week_to_day(const struct cal_control *ctl);
 static int center_str(const char *src, char *dest, size_t dest_size, size_t width);
 static void center(const char *str, size_t len, int separate);
+static int parse_reform_year(const char *reform_year);
 static void __attribute__((__noreturn__)) usage(void);
 
 int main(int argc, char **argv)
@@ -256,7 +265,7 @@ int main(int argc, char **argv)
        int ch = 0, yflag = 0, Yflag = 0;
 
        static struct cal_control ctl = {
-               .reform_year = 1752,
+               .reform_year = DEFAULT_REFORM_YEAR,
                .weekstart = SUNDAY,
                .num_months = 1,                /* default is "cal -1" */
                .span_months = 0,
@@ -269,7 +278,9 @@ int main(int argc, char **argv)
        };
 
        enum {
-               OPT_COLOR = CHAR_MAX + 1
+               OPT_COLOR = CHAR_MAX + 1,
+               OPT_ISO,
+               OPT_REFORM
        };
 
        static const struct option longopts[] = {
@@ -283,6 +294,8 @@ int main(int argc, char **argv)
                {"year", no_argument, NULL, 'y'},
                {"week", optional_argument, NULL, 'w'},
                {"color", optional_argument, NULL, OPT_COLOR},
+               {"reform", required_argument, NULL, OPT_REFORM},
+               {"iso", no_argument, NULL, OPT_ISO},
                {"version", no_argument, NULL, 'V'},
                {"twelve", no_argument, NULL, 'Y'},
                {"help", no_argument, NULL, 'h'},
@@ -395,6 +408,12 @@ int main(int argc, char **argv)
                                ctl.colormode = colormode_or_err(optarg,
                                                _("unsupported color mode"));
                        break;
+               case OPT_REFORM:
+                       ctl.reform_year = parse_reform_year(optarg);
+                       break;
+               case OPT_ISO:
+                       ctl.reform_year = ISO;
+                       break;
                case 'V':
                        printf(UTIL_LINUX_VERSION);
                        return EXIT_SUCCESS;
@@ -453,7 +472,7 @@ int main(int argc, char **argv)
                ctl.req.year = strtos32_or_err(*argv++, _("illegal year value"));
                if (ctl.req.year < SMALLEST_YEAR)
                        errx(EXIT_FAILURE, _("illegal year value: use positive integer"));
-               if (ctl.req.year == INT32_MAX)
+               if (ctl.req.year == JULIAN)
                        errx(EXIT_FAILURE, _("illegal year value"));
                if (ctl.req.day) {
                        int dm = days_in_month[leap_year(&ctl, ctl.req.year)]
@@ -905,14 +924,15 @@ static int day_in_week(const struct cal_control *ctl, int day,
            || (year == ctl->reform_year && REFORMATION_MONTH < month)
            || (year == ctl->reform_year
                && month == REFORMATION_MONTH && 13 < day)) {
-               int64_t long_year = year;
-               return (long_year + (year / 4) - (year / 100) + (year / 400) +
-                       reform[month - 1] + day) % DAYS_IN_WEEK;
+               return ((int64_t) year + (year / 4)
+                       - (year / 100) + (year / 400)
+                       + reform[month - 1] + day) % DAYS_IN_WEEK;
        }
        if (year < ctl->reform_year
            || (year == ctl->reform_year && month < REFORMATION_MONTH)
            || (year == ctl->reform_year && month == REFORMATION_MONTH && day < 3))
-               return (year + year / 4 + old[month - 1] + day) % DAYS_IN_WEEK;
+               return ((int64_t) year + year / 4 + old[month - 1] + day)
+                       % DAYS_IN_WEEK;
        return NONEDAY;
 }
 
@@ -1012,6 +1032,30 @@ static void center(const char *str, size_t len, int separate)
        }
 }
 
+static int parse_reform_year(const char *reform_year)
+{
+       size_t i;
+
+       struct reform {
+               char *name;
+               int val;
+       };
+
+       struct reform years[] = {
+       {"gregorian",   GREGORIAN},
+       {"iso",         ISO},
+       {"1752",        GB1752},
+       {"julian",      JULIAN},
+       };
+
+       for (i = 0; i < ARRAY_SIZE(years); i++) {
+               if (strcasecmp(reform_year, years[i].name) == 0) {
+                       return years[i].val;
+               }
+       }
+       errx(EXIT_FAILURE, "invalid --reform value: '%s'", reform_year);
+}
+
 static void __attribute__((__noreturn__)) usage(void)
 {
        FILE *out = stdout;
@@ -1030,7 +1074,9 @@ static void __attribute__((__noreturn__)) usage(void)
        fputs(_(" -S, --span            span the date when displaying multiple months\n"), out);
        fputs(_(" -s, --sunday          Sunday as first day of week\n"), out);
        fputs(_(" -m, --monday          Monday as first day of week\n"), out);
-       fputs(_(" -j, --julian          output Julian dates\n"), out);
+       fputs(_(" -j, --julian          use day-of-year for all calendars\n"), out);
+       fputs(_("     --reform <val>    Gregorian reform date (1752|gregorian|iso|julian)\n"), out);
+       fputs(_("     --iso             alias for --reform=iso\n"), out);
        fputs(_(" -y, --year            show the whole year\n"), out);
        fputs(_(" -Y, --twelve          show the next twelve months\n"), out);
        fputs(_(" -w, --week[=<num>]    show US or ISO-8601 week numbers\n"), out);