root/ext/date/date_strftime.c

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DEFINITIONS

This source file includes following definitions.
  1. upcase
  2. downcase
  3. date_strftime_with_tmx
  4. date_strftime

/*
  date_strftime.c: based on a public-domain implementation of ANSI C
  library routine strftime, which is originally written by Arnold
  Robbins.
 */

#include "ruby/ruby.h"
#include "date_tmx.h"

#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>

#if defined(HAVE_SYS_TIME_H)
#include <sys/time.h>
#endif

#undef strchr   /* avoid AIX weirdness */

#define range(low, item, hi)    (item)

#define add(x,y) (rb_funcall((x), '+', 1, (y)))
#define sub(x,y) (rb_funcall((x), '-', 1, (y)))
#define mul(x,y) (rb_funcall((x), '*', 1, (y)))
#define quo(x,y) (rb_funcall((x), rb_intern("quo"), 1, (y)))
#define div(x,y) (rb_funcall((x), rb_intern("div"), 1, (y)))
#define mod(x,y) (rb_funcall((x), '%', 1, (y)))

static void
upcase(char *s, size_t i)
{
    do {
        if (ISLOWER(*s))
            *s = TOUPPER(*s);
    } while (s++, --i);
}

static void
downcase(char *s, size_t i)
{
    do {
        if (ISUPPER(*s))
            *s = TOLOWER(*s);
    } while (s++, --i);
}

/* strftime --- produce formatted time */

static size_t
date_strftime_with_tmx(char *s, const size_t maxsize, const char *format,
                       const struct tmx *tmx)
{
    char *endp = s + maxsize;
    char *start = s;
    const char *sp, *tp;
    auto char tbuf[100];
    ptrdiff_t i;
    int v, w;
    size_t colons;
    int precision, flags;
    char padding;
    /* LOCALE_[OE] and COLONS are actually modifiers, not flags */
    enum {LEFT, CHCASE, LOWER, UPPER, LOCALE_O, LOCALE_E, COLONS};
#define BIT_OF(n) (1U<<(n))

    /* various tables for locale C */
    static const char days_l[][10] = {
        "Sunday", "Monday", "Tuesday", "Wednesday",
        "Thursday", "Friday", "Saturday",
    };
    static const char months_l[][10] = {
        "January", "February", "March", "April",
        "May", "June", "July", "August", "September",
        "October", "November", "December",
    };
    static const char ampm[][3] = { "AM", "PM", };

    if (s == NULL || format == NULL || tmx == NULL || maxsize == 0)
        return 0;

    /* quick check if we even need to bother */
    if (strchr(format, '%') == NULL && strlen(format) + 1 >= maxsize) {
      err:
        errno = ERANGE;
        return 0;
    }

    for (; *format && s < endp - 1; format++) {
#define FLAG_FOUND() do {                                               \
            if (precision > 0 || flags & (BIT_OF(LOCALE_E) | BIT_OF(LOCALE_O) | BIT_OF(COLONS))) \
                goto unknown;                                           \
        } while (0)
#define NEEDS(n) do if (s >= endp || (n) >= endp - s - 1) goto err; while (0)
#define FILL_PADDING(i) do {                                            \
            if (!(flags & BIT_OF(LEFT)) && precision > (i)) {           \
                NEEDS(precision);                                       \
                memset(s, padding ? padding : ' ', precision - (i));    \
                s += precision - (i);                                   \
            }                                                           \
            else {                                                      \
                NEEDS(i);                                               \
            }                                                           \
        } while (0);
#define FMT(def_pad, def_prec, fmt, val)                                \
        do {                                                            \
            int l;                                                      \
            if (precision <= 0) precision = (def_prec);                 \
            if (flags & BIT_OF(LEFT)) precision = 1;                    \
            l = snprintf(s, endp - s,                                   \
                         ((padding == '0' || (!padding && (def_pad) == '0')) ? \
                          "%0*"fmt : "%*"fmt),                          \
                         precision, (val));                             \
            if (l < 0) goto err;                                        \
            s += l;                                                     \
        } while (0)
#define STRFTIME(fmt)                                                   \
        do {                                                            \
            i = date_strftime_with_tmx(s, endp - s, (fmt), tmx);        \
            if (!i) return 0;                                           \
            if (flags & BIT_OF(UPPER))                                  \
                upcase(s, i);                                           \
            if (!(flags & BIT_OF(LEFT)) && precision > i) {             \
                if (start + maxsize < s + precision) {                  \
                    errno = ERANGE;                                     \
                    return 0;                                           \
                }                                                       \
                memmove(s + precision - i, s, i);                       \
                memset(s, padding ? padding : ' ', precision - i);      \
                s += precision;                                         \
            }                                                           \
            else s += i;                                                \
        } while (0)
#define FMTV(def_pad, def_prec, fmt, val)                               \
        do {                                                            \
            VALUE tmp = (val);                                          \
            if (FIXNUM_P(tmp)) {                                        \
                FMT((def_pad), (def_prec), "l"fmt, FIX2LONG(tmp));      \
            }                                                           \
            else {                                                      \
                VALUE args[2], result;                                  \
                size_t l;                                               \
                if (precision <= 0) precision = (def_prec);             \
                if (flags & BIT_OF(LEFT)) precision = 1;                \
                args[0] = INT2FIX(precision);                           \
                args[1] = (val);                                        \
                if (padding == '0' || (!padding && (def_pad) == '0'))   \
                    result = rb_str_format(2, args, rb_str_new2("%0*"fmt)); \
                else                                                    \
                    result = rb_str_format(2, args, rb_str_new2("%*"fmt)); \
                l = strlcpy(s, StringValueCStr(result), endp - s);      \
                if ((size_t)(endp - s) <= l)                            \
                    goto err;                                           \
                s += l;                                                 \
            }                                                           \
        } while (0)

        if (*format != '%') {
            *s++ = *format;
            continue;
        }
        tp = tbuf;
        sp = format;
        precision = -1;
        flags = 0;
        padding = 0;
        colons = 0;
      again:
        switch (*++format) {
          case '\0':
            format--;
            goto unknown;

          case 'A':     /* full weekday name */
          case 'a':     /* abbreviated weekday name */
            if (flags & BIT_OF(CHCASE)) {
                flags &= ~(BIT_OF(LOWER) | BIT_OF(CHCASE));
                flags |= BIT_OF(UPPER);
            }
            {
                int wday = tmx_wday;
                if (wday < 0 || wday > 6)
                    i = 1, tp = "?";
                else {
                    if (*format == 'A')
                        i = strlen(tp = days_l[wday]);
                    else
                        i = 3, tp = days_l[wday];
                }
            }
            break;

          case 'B':     /* full month name */
          case 'b':     /* abbreviated month name */
          case 'h':     /* same as %b */
            if (flags & BIT_OF(CHCASE)) {
                flags &= ~(BIT_OF(LOWER) | BIT_OF(CHCASE));
                flags |= BIT_OF(UPPER);
            }
            {
                int mon = tmx_mon;
                if (mon < 1 || mon > 12)
                    i = 1, tp = "?";
                else {
                    if (*format == 'B')
                        i = strlen(tp = months_l[mon - 1]);
                    else
                        i = 3, tp = months_l[mon - 1];
                }
            }
            break;

          case 'C':     /* century (year/100) */
            FMTV('0', 2, "d", div(tmx_year, INT2FIX(100)));
            continue;

          case 'c':     /* appropriate date and time representation */
            STRFTIME("%a %b %e %H:%M:%S %Y");
            continue;

          case 'D':
            STRFTIME("%m/%d/%y");
            continue;

          case 'd':     /* day of the month, 01 - 31 */
          case 'e':     /* day of month, blank padded */
            v = range(1, tmx_mday, 31);
            FMT((*format == 'd') ? '0' : ' ', 2, "d", v);
            continue;

          case 'F':
            STRFTIME("%Y-%m-%d");
            continue;

          case 'G':     /* year of ISO week with century */
          case 'Y':     /* year with century */
            {
                VALUE year = (*format == 'G') ? tmx_cwyear : tmx_year;
                if (FIXNUM_P(year)) {
                    long y = FIX2LONG(year);
                    FMT('0', 0 <= y ? 4 : 5, "ld", y);
                }
                else {
                    FMTV('0', 4, "d", year);
                }
            }
            continue;

          case 'g':     /* year of ISO week without a century */
          case 'y':     /* year without a century */
            v = NUM2INT(mod((*format == 'g') ? tmx_cwyear : tmx_year, INT2FIX(100)));
            FMT('0', 2, "d", v);
            continue;

          case 'H':     /* hour, 24-hour clock, 00 - 23 */
          case 'k':     /* hour, 24-hour clock, blank pad */
            v = range(0, tmx_hour, 23);
            FMT((*format == 'H') ? '0' : ' ', 2, "d", v);
            continue;

          case 'I':     /* hour, 12-hour clock, 01 - 12 */
          case 'l':     /* hour, 12-hour clock, 1 - 12, blank pad */
            v = range(0, tmx_hour, 23);
            if (v == 0)
                v = 12;
            else if (v > 12)
                v -= 12;
            FMT((*format == 'I') ? '0' : ' ', 2, "d", v);
            continue;

          case 'j':     /* day of the year, 001 - 366 */
            v = range(1, tmx_yday, 366);
            FMT('0', 3, "d", v);
            continue;

          case 'L':     /* millisecond */
          case 'N':     /* nanosecond */
            if (*format == 'L')
                w = 3;
            else
                w = 9;
            if (precision <= 0)
                precision = w;
            NEEDS(precision);

            {
                VALUE subsec = tmx_sec_fraction;
                int ww;
                long n;

                ww = precision;
                while (9 <= ww) {
                    subsec = mul(subsec, INT2FIX(1000000000));
                    ww -= 9;
                }
                n = 1;
                for (; 0 < ww; ww--)
                    n *= 10;
                if (n != 1)
                    subsec = mul(subsec, INT2FIX(n));
                subsec = div(subsec, INT2FIX(1));

                if (FIXNUM_P(subsec)) {
                    (void)snprintf(s, endp - s, "%0*ld",
                                   precision, FIX2LONG(subsec));
                    s += precision;
                }
                else {
                    VALUE args[2], result;
                    args[0] = INT2FIX(precision);
                    args[1] = subsec;
                    result = rb_str_format(2, args, rb_str_new2("%0*d"));
                    (void)strlcpy(s, StringValueCStr(result), endp - s);
                    s += precision;
                }
            }
            continue;

          case 'M':     /* minute, 00 - 59 */
            v = range(0, tmx_min, 59);
            FMT('0', 2, "d", v);
            continue;

          case 'm':     /* month, 01 - 12 */
            v = range(1, tmx_mon, 12);
            FMT('0', 2, "d", v);
            continue;

          case 'n':     /* same as \n */
            FILL_PADDING(1);
            *s++ = '\n';
            continue;

          case 't':     /* same as \t */
            FILL_PADDING(1);
            *s++ = '\t';
            continue;

          case 'P':     /* am or pm based on 12-hour clock */
          case 'p':     /* AM or PM based on 12-hour clock */
            if ((*format == 'p' && (flags & BIT_OF(CHCASE))) ||
                (*format == 'P' && !(flags & (BIT_OF(CHCASE) | BIT_OF(UPPER))))) {
                flags &= ~(BIT_OF(UPPER) | BIT_OF(CHCASE));
                flags |= BIT_OF(LOWER);
            }
            v = range(0, tmx_hour, 23);
            if (v < 12)
                tp = ampm[0];
            else
                tp = ampm[1];
            i = 2;
            break;

          case 'Q':     /* milliseconds since Unix epoch */
            FMTV('0', 1, "d", tmx_msecs);
            continue;

          case 'R':
            STRFTIME("%H:%M");
            continue;

          case 'r':
            STRFTIME("%I:%M:%S %p");
            continue;

          case 'S':     /* second, 00 - 59 */
            v = range(0, tmx_sec, 59);
            FMT('0', 2, "d", v);
            continue;

          case 's':     /* seconds since Unix epoch */
            FMTV('0', 1, "d", tmx_secs);
            continue;

          case 'T':
            STRFTIME("%H:%M:%S");
            continue;

          case 'U':     /* week of year, Sunday is first day of week */
          case 'W':     /* week of year, Monday is first day of week */
            v = range(0, (*format == 'U') ? tmx_wnum0 : tmx_wnum1, 53);
            FMT('0', 2, "d", v);
            continue;

          case 'u':     /* weekday, Monday == 1, 1 - 7 */
            v = range(1, tmx_cwday, 7);
            FMT('0', 1, "d", v);
            continue;

          case 'V':     /* week of year according ISO 8601 */
            v = range(1, tmx_cweek, 53);
            FMT('0', 2, "d", v);
            continue;

          case 'v':
            STRFTIME("%e-%b-%Y");
            continue;

          case 'w':     /* weekday, Sunday == 0, 0 - 6 */
            v = range(0, tmx_wday, 6);
            FMT('0', 1, "d", v);
            continue;

          case 'X':     /* appropriate time representation */
            STRFTIME("%H:%M:%S");
            continue;

          case 'x':     /* appropriate date representation */
            STRFTIME("%m/%d/%y");
            continue;

          case 'Z':     /* time zone name or abbreviation */
            if (flags & BIT_OF(CHCASE)) {
                flags &= ~(BIT_OF(UPPER) | BIT_OF(CHCASE));
                flags |= BIT_OF(LOWER);
            }
            {
                char *zone = tmx_zone;
                if (zone == NULL)
                    tp = "";
                else
                    tp = zone;
                i = strlen(tp);
            }
            break;

          case 'z':     /* offset from UTC */
            {
                long off, aoff;
                int hl, hw;

                off = tmx_offset;
                aoff = off;
                if (aoff < 0)
                    aoff = -off;

                if ((aoff / 3600) < 10)
                    hl = 1;
                else
                    hl = 2;
                hw = 2;
                if (flags & BIT_OF(LEFT) && hl == 1)
                    hw = 1;

                switch (colons) {
                  case 0: /* %z -> +hhmm */
                    precision = precision <= (3 + hw) ? hw : precision - 3;
                    NEEDS(precision + 3);
                    break;

                  case 1: /* %:z -> +hh:mm */
                    precision = precision <= (4 + hw) ? hw : precision - 4;
                    NEEDS(precision + 4);
                    break;

                  case 2: /* %::z -> +hh:mm:ss */
                    precision = precision <= (7 + hw) ? hw : precision - 7;
                    NEEDS(precision + 7);
                    break;

                  case 3: /* %:::z -> +hh[:mm[:ss]] */
                    {
                        if (aoff % 3600 == 0) {
                            precision = precision <= (1 + hw) ?
                                hw : precision - 1;
                            NEEDS(precision + 3);
                        }
                        else if (aoff % 60 == 0) {
                            precision = precision <= (4 + hw) ?
                                hw : precision - 4;
                            NEEDS(precision + 4);
                        }
                        else {
                            precision = precision <= (7 + hw) ?
                                hw : precision - 7;
                            NEEDS(precision + 7);
                        }
                    }
                    break;

                  default:
                    format--;
                    goto unknown;
                }
                if (padding == ' ' && precision > hl) {
                    i = snprintf(s, endp - s, "%*s", precision - hl, "");
                    precision = hl;
                    if (i < 0) goto err;
                    s += i;
                }
                if (off < 0) {
                    off = -off;
                    *s++ = '-';
                } else {
                    *s++ = '+';
                }
                i = snprintf(s, endp - s, "%.*ld", precision, off / 3600);
                if (i < 0) goto err;
                s += i;
                off = off % 3600;
                if (colons == 3 && off == 0)
                    continue;
                if (1 <= colons)
                    *s++ = ':';
                i = snprintf(s, endp - s, "%02d", (int)(off / 60));
                if (i < 0) goto err;
                s += i;
                off = off % 60;
                if (colons == 3 && off == 0)
                    continue;
                if (2 <= colons) {
                    *s++ = ':';
                    i = snprintf(s, endp - s, "%02d", (int)off);
                    if (i < 0) goto err;
                    s += i;
                }
            }
            continue;

          case '+':
            STRFTIME("%a %b %e %H:%M:%S %Z %Y");
            continue;

          case 'E':
            /* POSIX locale extensions, ignored for now */
            flags |= BIT_OF(LOCALE_E);
            if (*(format + 1) && strchr("cCxXyY", *(format + 1)))
                goto again;
            goto unknown;
          case 'O':
            /* POSIX locale extensions, ignored for now */
            flags |= BIT_OF(LOCALE_O);
            if (*(format + 1) && strchr("deHkIlmMSuUVwWy", *(format + 1)))
                goto again;
            goto unknown;

          case ':':
            flags |= BIT_OF(COLONS);
            {
                size_t l = strspn(format, ":");
                format += l;
                if (*format == 'z') {
                    colons = l;
                    format--;
                    goto again;
                }
                format -= l;
            }
            goto unknown;

          case '_':
            FLAG_FOUND();
            padding = ' ';
            goto again;

          case '-':
            FLAG_FOUND();
            flags |= BIT_OF(LEFT);
            goto again;

          case '^':
            FLAG_FOUND();
            flags |= BIT_OF(UPPER);
            goto again;

          case '#':
            FLAG_FOUND();
            flags |= BIT_OF(CHCASE);
            goto again;

          case '0':
            FLAG_FOUND();
            padding = '0';
          case '1':  case '2': case '3': case '4':
          case '5': case '6':  case '7': case '8': case '9':
            {
                char *e;
                unsigned long prec = strtoul(format, &e, 10);
                if (prec > INT_MAX || prec > maxsize) {
                    errno = ERANGE;
                    return 0;
                }
                precision = (int)prec;
                format = e - 1;
                goto again;
            }

          case '%':
            FILL_PADDING(1);
            *s++ = '%';
            continue;

          default:
          unknown:
            i = format - sp + 1;
            tp = sp;
            precision = -1;
            flags = 0;
            padding = 0;
            colons = 0;
            break;
        }
        if (i) {
            FILL_PADDING(i);
            memcpy(s, tp, i);
            switch (flags & (BIT_OF(UPPER) | BIT_OF(LOWER))) {
              case BIT_OF(UPPER):
                upcase(s, i);
                break;
              case BIT_OF(LOWER):
                downcase(s, i);
                break;
            }
            s += i;
        }
    }
    if (s >= endp) {
        goto err;
    }
    if (*format == '\0') {
        *s = '\0';
        return (s - start);
    }
    return 0;
}

size_t
date_strftime(char *s, size_t maxsize, const char *format,
              const struct tmx *tmx)
{
    return date_strftime_with_tmx(s, maxsize, format, tmx);
}

/*
Local variables:
c-file-style: "ruby"
End:
*/

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