cal: simplify ascii_weeknum() function

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

/*
 * Copyright (c) 1989, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kim Letkeman.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/* 1999-02-01   Jean-Francois Bignolles: added option '-m' to display
 *              monday as the first day of the week.
 * 1999-02-22 Arkadiusz Miśkiewicz <misiek@pld.ORG.PL>
 * - added Native Language Support
 *
 * 2000-09-01  Michael Charles Pruznick <dummy@netwiz.net>
 *             Added "-3" option to print prev/next month with current.
 *             Added over-ridable default NUM_MONTHS and "-1" option to
 *             get traditional output when -3 is the default.  I hope that
 *             enough people will like -3 as the default that one day the
 *             product can be shipped that way.
 *
 * 2001-05-07  Pablo Saratxaga <pablo@mandrakesoft.com>
 *             Fixed the bugs with multi-byte charset (zg: cjk, utf-8)
 *             displaying. made the 'month year' ("%s %d") header translatable
 *             so it can be adapted to conventions used by different languages
 *             added support to read "first_weekday" locale information
 *             still to do: support for 'cal_direction' (will require a major
 *             rewrite of the displaying) and proper handling of RTL scripts
 */

#include <sys/types.h>

#include <ctype.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <errno.h>

#include "c.h"
#include "closestream.h"
#include "colors.h"
#include "nls.h"
#include "mbsalign.h"
#include "strutils.h"

#if defined(HAVE_LIBNCURSES) || defined(HAVE_LIBNCURSESW)
# ifdef HAVE_NCURSES_H
#  include <ncurses.h>
# elif defined(HAVE_NCURSES_NCURSES_H)
#  include <ncurses/ncurses.h>
# endif
# include <term.h>

static void my_setupterm(const char *term, int fildes, int *errret)
{
        setupterm((char *)term, fildes, errret);
}

static void my_putstring(char *s)
{
        putp(s);
}

static const char *my_tgetstr(char *s __attribute__((__unused__)), char *ss)
{
        const char *ret = tigetstr(ss);
        if (!ret || ret == (char *)-1)
                return "";

        return ret;
}

#elif defined(HAVE_LIBTERMCAP)
# include <termcap.h>

static char termbuffer[4096];
static char tcbuffer[4096];
static char *strbuf = termbuffer;

static void my_setupterm(const char *term, int fildes __attribute__((__unused__)), int *errret)
{
        *errret = tgetent(tcbuffer, term);
}

static void my_putstring(char *s)
{
        tputs(s, 1, putchar);
}

static const char *my_tgetstr(char *s, char *ss __attribute__((__unused__)))
{
        const char *ret = tgetstr(s, &strbuf);
        if (!ret)
                return "";

        return ret;
}

#else   /* ! (HAVE_LIBTERMCAP || HAVE_LIBNCURSES || HAVE_LIBNCURSESW) */

static void my_putstring(char *s)
{
        fputs(s, stdout);
}

#endif  /* end of LIBTERMCAP / NCURSES */

#if defined(HAVE_LIBNCURSES) || defined(HAVE_LIBNCURSESW) || defined(HAVE_LIBTERMCAP)
static const char       *term="";
static int              Slen;           /* strlen of Senter+Sexit */
#endif

static const char       *Senter="", *Sexit="";/* enter and exit standout mode */
static char             *Hrow;          /* pointer to highlighted row in month */

#include "widechar.h"

/* allow compile-time define to over-ride default */
#ifndef NUM_MONTHS
# define NUM_MONTHS 1
#endif

#if ( NUM_MONTHS != 1 && NUM_MONTHS !=3 )
# error NUM_MONTHS must be 1 or 3
#endif

enum {
        SUNDAY = 0,
        MONDAY,
        TUESDAY,
        WEDNESDAY,
        THURSDAY,
        FRIDAY,
        SATURDAY,
        DAYS_IN_WEEK,
        NONEDAY
};

#define FIRST_WEEKDAY           SATURDAY        /* Jan 1st, 1 was a Saturday */
#define REFORMATION_YEAR        1752            /* Signed-off-by: Lord Chesterfield */
#define REFORMATION_MONTH       9               /* September */
#define FIRST_MISSING_DAY       639799          /* 3 Sep 1752 */
#define NUMBER_MISSING_DAYS     11              /* 11 day correction */
#define YDAY_AFTER_MISSING      258             /* 14th in Sep 1752 */

#define DAYS_IN_YEAR            365             /* the common case, leap years are calculated */
#define MONTHS_IN_YEAR          12
#define DAYS_IN_MONTH           31
#define MAXDAYS                 42              /* slots in a month array */
#define SPACE                   -1              /* used in day array */

#define SMALLEST_YEAR           1

#define DAY_LEN                 3               /* 3 spaces per day */
#define WEEK_LEN                (DAYS_IN_WEEK * DAY_LEN)
#define HEAD_SEP                2
#define MONTH_COLS              3               /* month columns in year view */
#define WNUM_LEN                3

#define J_DAY_LEN               4               /* 4 spaces per day */
#define J_WEEK_LEN              (DAYS_IN_WEEK * J_DAY_LEN)
#define J_HEAD_SEP              2
#define J_MONTH_COLS            2

#define TODAY_FLAG              0x400           /* flag day for highlighting */

#define FMT_ST_LINES 9
#define FMT_ST_CHARS 300        /* 90 suffices in most locales */
struct fmt_st
{
        char s[FMT_ST_LINES][FMT_ST_CHARS];
};

static const int days_in_month[2][13] = {
        {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
        {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
};

/* September 1752 is special, and has static assignments for both date
 * and Julian representations.  */
static const int d_sep1752[MAXDAYS / 2] = {
        SPACE,  SPACE,  1,      2,      14,     15,     16,
        17,     18,     19,     20,     21,     22,     23,
        24,     25,     26,     27,     28,     29,     30
}, j_sep1752[MAXDAYS / 2] = {
        SPACE,  SPACE,  245,    246,    258,    259,    260,
        261,    262,    263,    264,    265,    266,    267,
        268,    269,    270,    271,    272,    273,    274
}, empty[MAXDAYS] = {
        SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
        SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
        SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
        SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
        SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
        SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE
};

enum {
        WEEK_NUM_DISABLED = 0,
        WEEK_NUM_MASK=0xff,
        WEEK_NUM_ISO=0x100,
        WEEK_NUM_US=0x200,
};

/* utf-8 can have up to 6 bytes per char; and an extra byte for ending \0 */
static char day_headings[J_WEEK_LEN * 6 + 1];

struct cal_control {
        const char *full_month[MONTHS_IN_YEAR]; /* month names */
        int colormode;                  /* day and week number highlight */
        int num_months;                 /* number of months horizontally in print out */
        int weekstart;                  /* day the week starts, often Sun or Mon */
        int weektype;                   /* WEEK_TYPE_{NONE,ISO,US} */
        int weeknum;                    /* requested --week=<number> */
        unsigned int    julian:1,       /* julian output */
                        yflag:1;        /* print whole year */
};

/* function prototypes */
static int leap_year(long year);
static void headers_init(struct cal_control *ctl);
static int do_monthly(int day, int month, long year, struct fmt_st *out, int header_hint,
                      const struct cal_control *ctl);
static void monthly(int day, int month, long year, const struct cal_control *ctl);
static int two_header_lines(int month, long year, const struct cal_control *ctl);
static void monthly3(int day, int month, long year, const struct cal_control *ctl);
static char *append_weeknum(char *p, int *dp, int month, long year, int cal, int row,
                            const struct cal_control *ctl);
static void yearly(int day, long year, const struct cal_control *ctl);
static void day_array(int day, int month, long year, int *days, const struct cal_control *ctl);
static int day_in_year(int day, int month, long year);
static int day_in_week(int day, int month, long year);
static int week_number(int day, int month, long year, const struct cal_control *ctl);
static int week_to_day(long year, const struct cal_control *ctl);
static char *ascii_day(char *p, int day, const struct cal_control *ctl);
static char *ascii_weeknum(char *p, int weeknum, 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 void __attribute__((__noreturn__)) usage(FILE *out);

int main(int argc, char **argv)
{
        struct tm *local_time;
        time_t now;
        int ch, day = 0, month = 0;
        long year;
        static struct cal_control ctl = {
                .weekstart = SUNDAY,
                .num_months = NUM_MONTHS,
                .colormode = UL_COLORMODE_AUTO,
                .weektype = WEEK_NUM_DISABLED
        };

        enum {
                OPT_COLOR = CHAR_MAX + 1
        };

        static const struct option longopts[] = {
                {"one", no_argument, NULL, '1'},
                {"three", no_argument, NULL, '3'},
                {"sunday", no_argument, NULL, 's'},
                {"monday", no_argument, NULL, 'm'},
                {"julian", no_argument, NULL, 'j'},
                {"year", no_argument, NULL, 'y'},
                {"week", optional_argument, NULL, 'w'},
                {"color", optional_argument, NULL, OPT_COLOR},
                {"version", no_argument, NULL, 'V'},
                {"help", no_argument, NULL, 'h'},
                {NULL, 0, NULL, 0}
        };

        setlocale(LC_ALL, "");
        bindtextdomain(PACKAGE, LOCALEDIR);
        textdomain(PACKAGE);
        atexit(close_stdout);

#if defined(HAVE_LIBNCURSES) || defined(HAVE_LIBNCURSESW) || defined(HAVE_LIBTERMCAP)
        if ((term = getenv("TERM"))) {
                int ret;
                my_setupterm(term, STDOUT_FILENO, &ret);
                if (ret > 0) {
                        Senter = my_tgetstr("so","smso");
                        Sexit = my_tgetstr("se","rmso");
                        Slen = strlen(Senter) + strlen(Sexit);
                }
        }
#endif

/*
 * The traditional Unix cal utility starts the week at Sunday,
 * while ISO 8601 starts at Monday. We read the start day from
 * the locale database, which can be overridden with the
 * -s (Sunday) or -m (Monday) options.
 */
#if HAVE_DECL__NL_TIME_WEEK_1STDAY
        /*
         * You need to use 2 locale variables to get the first day of the week.
         * This is needed to support first_weekday=2 and first_workday=1 for
         * the rare case where working days span across 2 weeks.
         * This shell script shows the combinations and calculations involved:
         *
         * for LANG in en_US ru_RU fr_FR csb_PL POSIX; do
         *   printf "%s:\t%s + %s -1 = " $LANG $(locale week-1stday first_weekday)
         *   date -d"$(locale week-1stday) +$(($(locale first_weekday)-1))day" +%w
         * done
         *
         * en_US:  19971130 + 1 -1 = 0  #0 = sunday
         * ru_RU:  19971130 + 2 -1 = 1
         * fr_FR:  19971201 + 1 -1 = 1
         * csb_PL: 19971201 + 2 -1 = 2
         * POSIX:  19971201 + 7 -1 = 0
         */
        {
                int wfd;
                union { unsigned int word; char *string; } val;
                val.string = nl_langinfo(_NL_TIME_WEEK_1STDAY);

                wfd = val.word;
                wfd = day_in_week(wfd % 100, (wfd / 100) % 100, wfd / (100 * 100));
                ctl.weekstart = (wfd + *nl_langinfo(_NL_TIME_FIRST_WEEKDAY) - 1) % DAYS_IN_WEEK;
        }
#endif

        while ((ch = getopt_long(argc, argv, "13mjsywVh", longopts, NULL)) != -1)
                switch(ch) {
                case '1':
                        ctl.num_months = 1;             /* default */
                        break;
                case '3':
                        ctl.num_months = 3;
                        break;
                case 's':
                        ctl.weekstart = SUNDAY;         /* default */
                        break;
                case 'm':
                        ctl.weekstart = MONDAY;
                        break;
                case 'j':
                        ctl.julian = 1;
                        break;
                case 'y':
                        ctl.yflag = 1;
                        break;
                case 'w':
                        if (optarg) {
                                ctl.weeknum = strtos32_or_err(optarg,
                                                _("invalid week argument"));
                                if (ctl.weeknum < 1 || 53 < ctl.weeknum)
                                        errx(EXIT_FAILURE,_("illegal week value: use 1-53"));
                        }
                        ctl.weektype = WEEK_NUM_US;     /* default per weekstart */
                        break;
                case OPT_COLOR:
                        if (optarg)
                                ctl.colormode = colormode_or_err(optarg,
                                                _("unsupported color mode"));
                        break;
                case 'V':
                        printf(UTIL_LINUX_VERSION);
                        return EXIT_SUCCESS;
                case 'h':
                        usage(stdout);
                case '?':
                default:
                        usage(stderr);
                }
        argc -= optind;
        argv += optind;

        if (ctl.weektype) {
                ctl.weektype = ctl.weeknum & WEEK_NUM_MASK;
                ctl.weektype |= (ctl.weekstart == MONDAY ? WEEK_NUM_ISO : WEEK_NUM_US);
        }

        time(&now);
        local_time = localtime(&now);

        switch(argc) {
        case 3:
                day = strtos32_or_err(*argv++, _("illegal day value"));
                if (day < 1 || DAYS_IN_MONTH < day)
                        errx(EXIT_FAILURE, _("illegal day value: use 1-%d"), DAYS_IN_MONTH);
                /* FALLTHROUGH */
        case 2:
                month = strtos32_or_err(*argv++, _("illegal month value: use 1-12"));
                if (month < 1 || MONTHS_IN_YEAR < month)
                        errx(EXIT_FAILURE, _("illegal month value: use 1-12"));
                /* FALLTHROUGH */
        case 1:
                year = strtol_or_err(*argv++, _("illegal year value"));
                if (year < SMALLEST_YEAR)
                        errx(EXIT_FAILURE, _("illegal year value: use positive integer"));
                if (day) {
                        int dm = days_in_month[leap_year(year)][month];
                        if (day > dm)
                                errx(EXIT_FAILURE, _("illegal day value: use 1-%d"), dm);
                        day = day_in_year(day, month, year);
                } else if ((long) (local_time->tm_year + 1900) == year) {
                        day = local_time->tm_yday + 1;
                }
                if (!month && !ctl.weeknum)
                        ctl.yflag = 1;
                break;
        case 0:
                day = local_time->tm_yday + 1;
                year = local_time->tm_year + 1900;
                month = local_time->tm_mon + 1;
                break;
        default:
                usage(stderr);
        }

        if (0 < ctl.weeknum) {
                int yday = week_to_day(year, &ctl);
                int leap = leap_year(year);

                if (yday < 1)
                        errx(EXIT_FAILURE, _("illegal week value: year %ld "
                                             "doesn't have week %d"),
                                        year, ctl.weeknum);
                month = 1;
                while (month <= 12 && yday > days_in_month[leap][month])
                        yday -= days_in_month[leap][month++];
                if (month > 12) {
                        /* In some years (e.g. 2010 in ISO mode) it's possible
                         * to have a remnant of week 53 starting the year yet
                         * the year in question ends during 52, in this case
                         * we're assuming that early remnant is being referred
                         * to if 53 is given as argument. */
                        if (ctl.weeknum == week_number(31, 12, year - 1, &ctl))
                                month = 1;
                        else
                                errx(EXIT_FAILURE,
                                        _("illegal week value: year %ld "
                                          "doesn't have week %d"),
                                        year, ctl.weeknum);
                }
        }

        headers_init(&ctl);

        if (!colors_init(ctl.colormode)) {
                day = 0;
                ctl.weektype &= ~WEEK_NUM_MASK;
        }

        if (ctl.yflag)
                yearly(day, year, &ctl);
        else if (ctl.num_months == 1)
                monthly(day, month, year, &ctl);
        else if (ctl.num_months == 3)
                monthly3(day, month, year, &ctl);

        return EXIT_SUCCESS;
}

/* leap year -- account for gregorian reformation in 1752 */
static int leap_year(long year)
{
        if (year <= REFORMATION_YEAR)
                return !(year % 4);
        else
                return ( !(year % 4) && (year % 100) ) || !(year % 400);
}

static void headers_init(struct cal_control *ctl)
{
        size_t i, wd, spaces = ctl->julian ? J_DAY_LEN - 1 : DAY_LEN - 1;
        char *cur_dh = day_headings;

        for (i = 0; i < DAYS_IN_WEEK; i++) {
                size_t space_left;
                wd = (i + ctl->weekstart) % DAYS_IN_WEEK;

                if (i)
                        strcat(cur_dh++, " ");
                space_left = sizeof(day_headings) - (cur_dh - day_headings);

                if (space_left <= spaces)
                        break;
                cur_dh += center_str(nl_langinfo(ABDAY_1 + wd), cur_dh,
                                     space_left, spaces);
        }

        for (i = 0; i < MONTHS_IN_YEAR; i++)
                ctl->full_month[i] = nl_langinfo(MON_1 + i);
}

static int do_monthly(int day, int month, long year, struct fmt_st *out,
                      int header_hint, const struct cal_control *ctl)
{
        int col, row, days[MAXDAYS];
        char *p, lineout[FMT_ST_CHARS];
        size_t width = (ctl->julian ? J_WEEK_LEN : WEEK_LEN) - 1
                       + (ctl->weektype ? WNUM_LEN : 0);
        int pos = 0;

        day_array(day, month, year, days, ctl);

        if (header_hint < 0)
                header_hint = two_header_lines(month, year, ctl);
        if (header_hint) {
                snprintf(lineout, sizeof(lineout), _("%s"), ctl->full_month[month - 1]);
                center_str(lineout, out->s[pos], ARRAY_SIZE(out->s[pos]), width);
                pos++;
                snprintf(lineout, sizeof(lineout), _("%ld"), year);
                center_str(lineout, out->s[pos], ARRAY_SIZE(out->s[pos]), width);
                pos++;
        } else {
                /* TRANSLATORS: %s is the month name, %ld the year number.
                 * You can change the order and/or add something here;
                 * e.g. for Basque the translation should be "%2$ldko %1$s".
                 */
                snprintf(lineout, sizeof(lineout), _("%s %ld"),
                        ctl->full_month[month - 1], year);
                center_str(lineout, out->s[pos], ARRAY_SIZE(out->s[pos]), width);
                pos++;
        }

        snprintf(out->s[pos++], FMT_ST_CHARS, "%s%s",
                                (ctl->weektype ? "   " : ""),
                                day_headings);

        for (row = 0; row < DAYS_IN_WEEK - 1; row++) {
                int has_hl = 0;
                p = lineout;
                if (ctl->weektype)
                        for (col = 0; col < DAYS_IN_WEEK; col++) {
                                int xd = days[row * DAYS_IN_WEEK + col];
                                if (xd != SPACE) {
                                        int wn = week_number(xd & ~TODAY_FLAG,
                                                        month, year, ctl);
                                        p = ascii_weeknum(p, wn, ctl);
                                        break;
                                } else if (col+1 == DAYS_IN_WEEK)
                                        p += sprintf(p,"   ");
                        }
                for (col = 0; col < DAYS_IN_WEEK; col++) {
                        int xd = days[row * DAYS_IN_WEEK + col];
                        if (xd != SPACE && (xd & TODAY_FLAG))
                                has_hl = 1;
                        p = ascii_day(p, xd, ctl);
                }
                *p = '\0';
                snprintf(out->s[row+pos], FMT_ST_CHARS, "%s", lineout);
                if (has_hl)
                        Hrow = out->s[row+pos];
        }
        pos += row;
        return pos;
}

static void monthly(int day, int month, long year, const struct cal_control *ctl)
{
        int i, rows;
        struct fmt_st out;

        rows = do_monthly(day, month, year, &out, -1, ctl);
        for (i = 0; i < rows; i++) {
                my_putstring(out.s[i]);
                my_putstring("\n");
        }
}

static int two_header_lines(int month, long year, const struct cal_control *ctl)
{
        char lineout[FMT_ST_CHARS];
        size_t width = (ctl->julian ? J_WEEK_LEN : WEEK_LEN) - 1;
        size_t len;
        snprintf(lineout, sizeof(lineout), "%ld", year);
        len = strlen(lineout);
        len += strlen(ctl->full_month[month - 1]) + 1;
        if (width < len)
                return 1;
        return 0;
}

static void monthly3(int day, int month, long year, const struct cal_control *ctl)
{
        char lineout[FMT_ST_CHARS];
        int i;
        int width, rows, two_lines;
        struct fmt_st out_prev;
        struct fmt_st out_curm;
        struct fmt_st out_next;
        int prev_month, next_month;
        long prev_year, next_year;

        memset(&out_prev, 0, sizeof(struct fmt_st));
        memset(&out_curm, 0, sizeof(struct fmt_st));
        memset(&out_next, 0, sizeof(struct fmt_st));
        if (month == 1) {
                prev_month = MONTHS_IN_YEAR;
                prev_year  = year - 1;
        } else {
                prev_month = month - 1;
                prev_year  = year;
        }
        if (month == MONTHS_IN_YEAR) {
                next_month = 1;
                next_year  = year + 1;
        } else {
                next_month = month + 1;
                next_year  = year;
        }
        two_lines = two_header_lines(prev_month, prev_year, ctl);
        two_lines += two_header_lines(month, year, ctl);
        two_lines += two_header_lines(next_month, next_year, ctl);
        if (0 < two_lines)
                rows = FMT_ST_LINES;
        else
                rows = FMT_ST_LINES - 1;
        do_monthly(day, prev_month, prev_year, &out_prev, two_lines, ctl);
        do_monthly(day, month,      year,      &out_curm, two_lines, ctl);
        do_monthly(day, next_month, next_year, &out_next, two_lines, ctl);

        width = (ctl->julian ? J_WEEK_LEN : WEEK_LEN) -1;
        for (i = 0; i < (two_lines ? 3 : 2); i++) {
                snprintf(lineout, sizeof(lineout),
                        "%s  %s  %s\n", out_prev.s[i], out_curm.s[i], out_next.s[i]);
                my_putstring(lineout);
        }
        for (i = two_lines ? 3 : 2; i < rows; i++) {
                int w1, w2, w3;
                w1 = w2 = w3 = width;

#if defined(HAVE_LIBNCURSES) || defined(HAVE_LIBNCURSESW) || defined(HAVE_LIBTERMCAP)
                /* adjust width to allow for non printable characters */
                w1 += (out_prev.s[i] == Hrow ? Slen : 0);
                w2 += (out_curm.s[i] == Hrow ? Slen : 0);
                w3 += (out_next.s[i] == Hrow ? Slen : 0);
#endif
                snprintf(lineout, sizeof(lineout), "%-*s %-*s %-*s\n",
                       w1, out_prev.s[i],
                       w2, out_curm.s[i],
                       w3, out_next.s[i]);

                my_putstring(lineout);
        }
}

static char *append_weeknum(char *p, int *dp,
                         int month, long year, int cal,
                         int row, const struct cal_control *ctl)
{
        int col;

        for (col = 0; col < DAYS_IN_WEEK; col++) {
                int xd = dp[row * DAYS_IN_WEEK + col];

                if (xd != SPACE) {
                        int weeknum = week_number(xd & ~TODAY_FLAG,
                                               month + cal + 1, year, ctl);
                        p = ascii_weeknum(p, weeknum, ctl);
                        break;
                } else if (col+1 == DAYS_IN_WEEK)
                        p += sprintf(p,"   ");
        }
        return p;
}

static void yearly(int day, long year, const struct cal_control *ctl)
{
        int col, i, month, row, which_cal;
        int maxrow, sep_len, week_len;
        int days[MONTHS_IN_YEAR][MAXDAYS];
        char *p;
        /* three weeks + separators + \0 */
        int weeknumlen = (ctl->weektype ? WNUM_LEN : 0);
        char lineout[ weeknumlen + sizeof(day_headings) + 2 +
                      weeknumlen + sizeof(day_headings) + 2 +
                      weeknumlen + sizeof(day_headings) + 1 ];
        if (ctl->julian) {
                maxrow = J_MONTH_COLS;
                sep_len = J_HEAD_SEP;
                week_len = J_WEEK_LEN + weeknumlen;
        } else {
                maxrow = MONTH_COLS;
                sep_len = HEAD_SEP;
                week_len = WEEK_LEN + weeknumlen;
        }
        snprintf(lineout, sizeof(lineout), "%ld", year);

        /* 2013-04-28: The -1 near sep_len makes year header to be aligned
         * exactly how it has been aligned for long time, but it is
         * unexplainable.  */
        center(lineout, (week_len + sep_len) * maxrow - sep_len - 1, 0);
        my_putstring("\n\n");

        for (i = 0; i < MONTHS_IN_YEAR; i++)
                day_array(day, i + 1, year, days[i], ctl);

        for (month = 0; month < MONTHS_IN_YEAR; month += maxrow) {
                center(ctl->full_month[month], week_len - 1, sep_len + 1);
                if (ctl->julian) {
                        center(ctl->full_month[month + 1], week_len - 1, 0);
                } else {
                        center(ctl->full_month[month + 1], week_len - 1, sep_len + 1);
                        center(ctl->full_month[month + 2], week_len - 1, 0);
                }
                if (ctl->julian)
                        snprintf(lineout, sizeof(lineout),
                                 "\n%*s%s%*s %*s%s\n",
                                 weeknumlen,"", day_headings, sep_len, "",
                                 weeknumlen,"", day_headings);
                else
                        snprintf(lineout, sizeof(lineout),
                                 "\n%*s%s%*s %*s%s%*s %*s%s\n",
                                 weeknumlen,"", day_headings, sep_len, "",
                                 weeknumlen,"", day_headings, sep_len, "",
                                 weeknumlen,"", day_headings);

                my_putstring(lineout);
                for (row = 0; row < DAYS_IN_WEEK - 1; row++) {
                        p = lineout;
                        for (which_cal = 0; which_cal < maxrow; which_cal++) {
                                int *dp = &days[month + which_cal][row * DAYS_IN_WEEK];

                                if (ctl->weektype)
                                        p = append_weeknum(p, days[month + which_cal],
                                                        month, year, which_cal,
                                                        row, ctl);

                                for (col = 0; col < DAYS_IN_WEEK; col++)
                                        p = ascii_day(p, *dp++, ctl);
                                p += sprintf(p, "  ");
                        }
                        *p = '\0';
                        my_putstring(lineout);
                        my_putstring("\n");
                }
        }
        my_putstring("\n");
}

/*
 * day_array --
 *      Fill in an array of 42 integers with a calendar.  Assume for a moment
 *      that you took the (maximum) 6 rows in a calendar and stretched them
 *      out end to end.  You would have 42 numbers or spaces.  This routine
 *      builds that array for any month from Jan. 1 through Dec. 9999.
 */
static void day_array(int day, int month, long year, int *days, const struct cal_control *ctl)
{
        int julday, daynum, dw, dm;
        const int *sep1752;

        memcpy(days, empty, MAXDAYS * sizeof(int));
        if (year == REFORMATION_YEAR && month == REFORMATION_MONTH) {
                sep1752 = ctl->julian ? j_sep1752 : d_sep1752;
                memcpy(days, sep1752 + ctl->weekstart,
                       ((MAXDAYS / 2) - ctl->weekstart) * sizeof(int));
                for (dm = 0; dm < MAXDAYS / 2; dm++)
                        if (j_sep1752[dm] == day)
                                days[dm] |= TODAY_FLAG;
                return;
        }
        dm = days_in_month[leap_year(year)][month];
        dw = (day_in_week(1, month, year) - ctl->weekstart + DAYS_IN_WEEK) % DAYS_IN_WEEK;
        julday = day_in_year(1, month, year);
        daynum = ctl->julian ? julday : 1;

        while (dm--) {
                days[dw] = daynum++;
                if (julday++ == day)
                        days[dw] |= TODAY_FLAG;
                dw++;
        }
}

/*
 * day_in_year --
 *      return the 1 based day number within the year
 */
static int day_in_year(int day, int month, long year)
{
        int i, leap;

        leap = leap_year(year);
        for (i = 1; i < month; i++)
                day += days_in_month[leap][i];
        return day;
}

/*
 * day_in_week
 *      return the 0 based day number for any date from 1 Jan. 1 to
 *      31 Dec. 9999.  Assumes the Gregorian reformation eliminates
 *      3 Sep. 1752 through 13 Sep. 1752, and returns invalid weekday
 *      during the period of 11 days.
 */
static int day_in_week(int day, int month, long year)
{
        static const int reform[] = {
                SUNDAY, WEDNESDAY, TUESDAY, FRIDAY, SUNDAY, WEDNESDAY,
                FRIDAY, MONDAY, THURSDAY, SATURDAY, TUESDAY, THURSDAY
        };
        static const int old[] = {
                FRIDAY, MONDAY, SUNDAY, WEDNESDAY, FRIDAY, MONDAY,
                WEDNESDAY, SATURDAY, TUESDAY, THURSDAY, SUNDAY, TUESDAY
        };
        if (year != 1753)
                year -= month < 3;
        else
                year -= (month < 3) + 14;
        if (REFORMATION_YEAR < year
            || (year == REFORMATION_YEAR && 9 < month)
            || (year == REFORMATION_YEAR && month == 9 && 13 < day))
                return (year + (year / 4) - (year / 100) + (year / 400) + reform[month - 1] +
                        day) % 7;
        if (year < REFORMATION_YEAR
            || (year == REFORMATION_YEAR && month < 9)
            || (year == REFORMATION_YEAR && month == 9 && day < 3))
                return (year + year / 4 + old[month - 1] + day) % 7;
        return NONEDAY;
}

/*
 * week_number
 *      return the week number of a given date, 1..53.
 *      Supports ISO-8601 and North American modes.
 *      Day may be given as Julian day of the year mode, in which
 *      case the month is disregarded entirely.
 */
static int week_number(int day, int month, long year, const struct cal_control *ctl)
{
        int fday = 0, yday;
        int wday = day_in_week(1, 1, year);

        if (ctl->weektype & WEEK_NUM_ISO)
                fday = wday + (wday >= FRIDAY ? -2 : 5);
        else
                /* WEEK_NUM_US
                 * - according to gcal, the first Sun is in the first week
                 * - according to wikipedia, the first Sat is in the first week
                 */
                fday = wday + (wday == SUNDAY ? 6 : -1);

        /* For julian dates the month can be set to 1, the global julian
         * variable cannot be relied upon here, because we may recurse
         * internally for 31.12. which would not work. */
        if (day > 31)
                month = 1;

        yday = day_in_year(day,month,year);
        if (year == REFORMATION_YEAR) {
                if (yday >= YDAY_AFTER_MISSING)
                        fday -= NUMBER_MISSING_DAYS;
        }

        /* Last year is last year */
        if (yday + fday < 7)
                return week_number(31, 12, year - 1, ctl);

        /* Or it could be part of the next year.  The reformation year had less
         * days than 365 making this check invalid, but reformation year ended
         * on Sunday and in week 51, so it's ok here. */
        if (ctl->weektype == WEEK_NUM_ISO && yday >= 363
            && day_in_week(day, month, year) >= MONDAY
            && day_in_week(day, month, year) <= WEDNESDAY
            && day_in_week(31, 12, year) >= MONDAY
            && day_in_week(31, 12, year) <= WEDNESDAY)
                return  week_number(1, 1, year + 1, ctl);

        return (yday + fday) / 7;
}

/*
 * week_to_day
 *      return the yday of the first day in a given week inside
 *      the given year. This may be something other than Monday
 *      for ISO-8601 modes. For North American numbering this
 *      always returns a Sunday.
 */
static int week_to_day(long year, const struct cal_control *ctl)
{
        int yday, wday;

        wday = day_in_week(1, 1, year);
        yday = ctl->weeknum * 7 - wday;

        if (ctl->weektype & WEEK_NUM_ISO)
                yday -= (wday >= FRIDAY ? -2 : 5);
        else
                yday -= (wday == SUNDAY ? 6 : -1);      /* WEEK_NUM_US */
        if (yday <= 0)
                return 1;

        return yday;
}

static char *ascii_day(char *p, int day, const struct cal_control *ctl)
{
        int display, val;
        int highlight = 0;
        static char *aday[] = {
                "",
                " 1", " 2", " 3", " 4", " 5", " 6", " 7",
                " 8", " 9", "10", "11", "12", "13", "14",
                "15", "16", "17", "18", "19", "20", "21",
                "22", "23", "24", "25", "26", "27", "28",
                "29", "30", "31",
        };

        if (day == SPACE) {
                int len = ctl->julian ? J_DAY_LEN : DAY_LEN;
                memset(p, ' ', len);
                return p+len;
        }
        if (day & TODAY_FLAG) {
                day &= ~TODAY_FLAG;
                p += sprintf(p, "%s", Senter);
                highlight = 1;
        }
        if (ctl->julian) {
                if ((val = day / 100)) {
                        day %= 100;
                        *p++ = val + '0';
                        display = 1;
                } else {
                        *p++ = ' ';
                        display = 0;
                }
                val = day / 10;
                if (val || display)
                        *p++ = val + '0';
                else
                        *p++ = ' ';
                *p++ = day % 10 + '0';
        } else {
                *p++ = aday[day][0];
                *p++ = aday[day][1];
        }
        if (highlight)
                p += sprintf(p, "%s", Sexit);
        *p++ = ' ';
        return p;
}

static char *ascii_weeknum(char *p, int weeknum, const struct cal_control *ctl)
{
        if ((ctl->weektype & WEEK_NUM_MASK) == weeknum)
                p += sprintf(p, "%s%2d%s ", Senter, weeknum, Sexit);
        else
                p += sprintf(p, "%2d ", weeknum);
        return p;
}

/*
 * Center string, handling multibyte characters appropriately.
 * In addition if the string is too large for the width it's truncated.
 * The number of trailing spaces may be 1 less than the number of leading spaces.
 */
static int center_str(const char* src, char* dest,
                      size_t dest_size, size_t width)
{
        return mbsalign(src, dest, dest_size, &width,
                        MBS_ALIGN_CENTER, MBA_UNIBYTE_FALLBACK);
}

static void center(const char *str, size_t len, int separate)
{
        char lineout[FMT_ST_CHARS];

        center_str(str, lineout, ARRAY_SIZE(lineout), len);
        my_putstring(lineout);

        if (separate) {
                snprintf(lineout, sizeof(lineout), "%*s", separate, "");
                my_putstring(lineout);
        }
}

static void __attribute__ ((__noreturn__)) usage(FILE * out)
{
        fputs(USAGE_HEADER, out);
        fprintf(out, _(" %s [options] [[[day] month] year]\n"), program_invocation_short_name);

        fputs(USAGE_SEPARATOR, out);
        fputs(_("Display a calendar, or some part of it.\n"), out);
        fputs(_("Without any arguments, display the current month.\n"), out);

        fputs(USAGE_OPTIONS, out);
        fputs(_(" -1, --one             show only a single month (default)\n"), out);
        fputs(_(" -3, --three           show three months spanning the date\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(_(" -y, --year            show the whole year\n"), out);
        fputs(_(" -w, --week[=<num>]    show US or ISO-8601 week numbers\n"), out);
        fputs(_("     --color[=<when>]  colorize messages (auto, always or never)\n"), out);

        fputs(USAGE_SEPARATOR, out);
        fputs(USAGE_HELP, out);
        fputs(USAGE_VERSION, out);
        fprintf(out, USAGE_MAN_TAIL("cal(1)"));

        exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}