strftime_l.c

Linux下头文件time.h的实现源码

	    pad = L_('_');

	do_number:
	  /* Format the number according to the MODIFIER flag.  */

	  if (modifier == L_('O') && 0 <= number_value)
	    {
#ifdef _NL_CURRENT
	      /* Get the locale specific alternate representation of
		 the number NUMBER_VALUE.  If none exist NULL is returned.  */
	      const CHAR_T *cp = nl_get_alt_digit (number_value
						   HELPER_LOCALE_ARG);

	      if (cp != NULL)
		{
		  size_t digitlen = STRLEN (cp);
		  if (digitlen != 0)
		    {
		      cpy (digitlen, cp);
		      break;
		    }
		}
#else
# if HAVE_STRFTIME
	      goto underlying_strftime;
# endif
#endif
	    }
	  {
	    unsigned int u = number_value;

	    bufp = buf + sizeof (buf) / sizeof (buf[0]);
	    negative_number = number_value < 0;

	    if (negative_number)
	      u = -u;

	    do
	      *--bufp = u % 10 + L_('0');
	    while ((u /= 10) != 0);
  	  }

	do_number_sign_and_padding:
	  if (negative_number)
	    *--bufp = L_('-');

	  if (pad != L_('-'))
	    {
	      int padding = digits - (buf + (sizeof (buf) / sizeof (buf[0]))
				      - bufp);

	      if (padding > 0)
		{
		  if (pad == L_('_'))
		    {
		      if ((size_t) padding >= maxsize - i)
			return 0;

		      if (p)
			memset_space (p, padding);
		      i += padding;
		      width = width > padding ? width - padding : 0;
		    }
		  else
		    {
		      if ((size_t) digits >= maxsize - i)
			return 0;

		      if (negative_number)
			{
			  ++bufp;

			  if (p)
			    *p++ = L_('-');
			  ++i;
			}

		      if (p)
			memset_zero (p, padding);
		      i += padding;
		      width = 0;
		    }
		}
	    }

	  cpy (buf + sizeof (buf) / sizeof (buf[0]) - bufp, bufp);
	  break;

	case L_('F'):
	  if (modifier != 0)
	    goto bad_format;
	  subfmt = L_("%Y-%m-%d");
	  goto subformat;

	case L_('H'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, tp->tm_hour);

	case L_('I'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, hour12);

	case L_('k'):		/* GNU extension.  */
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER_SPACEPAD (2, tp->tm_hour);

	case L_('l'):		/* GNU extension.  */
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER_SPACEPAD (2, hour12);

	case L_('j'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (3, 1 + tp->tm_yday);

	case L_('M'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, tp->tm_min);

	case L_('m'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, tp->tm_mon + 1);

	case L_('n'):
	  add (1, *p = L_('\n'));
	  break;

	case L_('P'):
	  to_lowcase = 1;
#if !defined _NL_CURRENT && HAVE_STRFTIME
	  format_char = L_('p');
#endif
	  /* FALLTHROUGH */

	case L_('p'):
	  if (change_case)
	    {
	      to_uppcase = 0;
	      to_lowcase = 1;
	    }
#if defined _NL_CURRENT || !HAVE_STRFTIME
	  cpy (ap_len, ampm);
	  break;
#else
	  goto underlying_strftime;
#endif

	case L_('R'):
	  subfmt = L_("%H:%M");
	  goto subformat;

	case L_('r'):
#if !defined _NL_CURRENT && HAVE_STRFTIME
	  goto underlying_strftime;
#else
# ifdef _NL_CURRENT
	  if (*(subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME,
						       NLW(T_FMT_AMPM)))
	      == L_('\0'))
# endif
	    subfmt = L_("%I:%M:%S %p");
	  goto subformat;
#endif

	case L_('S'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, tp->tm_sec);

	case L_('s'):		/* GNU extension.  */
  	  {
	    struct tm ltm;
	    time_t t;

	    ltm = *tp;
	    t = mktime (&ltm);

	    /* Generate string value for T using time_t arithmetic;
	       this works even if sizeof (long) < sizeof (time_t).  */

	    bufp = buf + sizeof (buf) / sizeof (buf[0]);
	    negative_number = t < 0;

	    do
	      {
		int d = t % 10;
		t /= 10;

		if (negative_number)
		  {
		    d = -d;

		    /* Adjust if division truncates to minus infinity.  */
		    if (0 < -1 % 10 && d < 0)
		      {
			t++;
			d += 10;
		      }
		  }

		*--bufp = d + L_('0');
	      }
	    while (t != 0);

	    digits = 1;
	    goto do_number_sign_and_padding;
	  }

	case L_('X'):
	  if (modifier == L_('O'))
	    goto bad_format;
#ifdef _NL_CURRENT
	  if (! (modifier == L_('E')
		 && (*(subfmt =
		       (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(ERA_T_FMT)))
		     != L_('\0'))))
	    subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(T_FMT));
	  goto subformat;
#else
# if HAVE_STRFTIME
	  goto underlying_strftime;
# else
	  /* Fall through.  */
# endif
#endif
	case L_('T'):
	  subfmt = L_("%H:%M:%S");
	  goto subformat;

	case L_('t'):
	  add (1, *p = L_('\t'));
	  break;

	case L_('u'):
	  DO_NUMBER (1, (tp->tm_wday - 1 + 7) % 7 + 1);

	case L_('U'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, (tp->tm_yday - tp->tm_wday + 7) / 7);

	case L_('V'):
	case L_('g'):
	case L_('G'):
	  if (modifier == L_('E'))
	    goto bad_format;
	  {
	    int year = tp->tm_year + TM_YEAR_BASE;
	    int days = iso_week_days (tp->tm_yday, tp->tm_wday);

	    if (days < 0)
	      {
		/* This ISO week belongs to the previous year.  */
		year--;
		days = iso_week_days (tp->tm_yday + (365 + __isleap (year)),
				      tp->tm_wday);
	      }
	    else
	      {
		int d = iso_week_days (tp->tm_yday - (365 + __isleap (year)),
				       tp->tm_wday);
		if (0 <= d)
		  {
		    /* This ISO week belongs to the next year.  */
		    year++;
		    days = d;
		  }
	      }

	    switch (*f)
	      {
	      case L_('g'):
		DO_NUMBER (2, (year % 100 + 100) % 100);

	      case L_('G'):
		DO_NUMBER (1, year);

	      default:
		DO_NUMBER (2, days / 7 + 1);
	      }
	  }

	case L_('W'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (2, (tp->tm_yday - (tp->tm_wday - 1 + 7) % 7 + 7) / 7);

	case L_('w'):
	  if (modifier == L_('E'))
	    goto bad_format;

	  DO_NUMBER (1, tp->tm_wday);

	case L_('Y'):
	  if (modifier == 'E')
	    {
#if HAVE_STRUCT_ERA_ENTRY
	      struct era_entry *era = _nl_get_era_entry (tp HELPER_LOCALE_ARG);
	      if (era)
		{
# ifdef COMPILE_WIDE
		  subfmt = era->era_wformat;
# else
		  subfmt = era->era_format;
# endif
		  goto subformat;
		}
#else
# if HAVE_STRFTIME
	      goto underlying_strftime;
# endif
#endif
	    }
	  if (modifier == L_('O'))
	    goto bad_format;
	  else
	    DO_NUMBER (1, tp->tm_year + TM_YEAR_BASE);

	case L_('y'):
	  if (modifier == L_('E'))
	    {
#if HAVE_STRUCT_ERA_ENTRY
	      struct era_entry *era = _nl_get_era_entry (tp HELPER_LOCALE_ARG);
	      if (era)
		{
		  int delta = tp->tm_year - era->start_date[0];
		  DO_NUMBER (1, (era->offset
				 + delta * era->absolute_direction));
		}
#else
# if HAVE_STRFTIME
	      goto underlying_strftime;
# endif
#endif
	    }
	  DO_NUMBER (2, (tp->tm_year % 100 + 100) % 100);

	case L_('Z'):
	  if (change_case)
	    {
	      to_uppcase = 0;
	      to_lowcase = 1;
	    }

#if HAVE_TZNAME
	  /* The tzset() call might have changed the value.  */
	  if (!(zone && *zone) && tp->tm_isdst >= 0)
	    zone = tzname[tp->tm_isdst];
#endif
	  if (! zone)
	    zone = "";

#ifdef COMPILE_WIDE
	  {
	    /* The zone string is always given in multibyte form.  We have
	       to transform it first.  */
	    wchar_t *wczone;
	    size_t len;
	    widen (zone, wczone, len);
	    cpy (len, wczone);
	  }
#else
	  cpy (strlen (zone), zone);
#endif
	  break;

	case L_('z'):
	  if (tp->tm_isdst < 0)
	    break;

	  {
	    int diff;
#if HAVE_TM_GMTOFF
	    diff = tp->tm_gmtoff;
#else
	    if (ut)
	      diff = 0;
	    else
	      {
		struct tm gtm;
		struct tm ltm;
		time_t lt;

		ltm = *tp;
		lt = mktime (&ltm);

		if (lt == (time_t) -1)
		  {
		    /* mktime returns -1 for errors, but -1 is also a
		       valid time_t value.  Check whether an error really
		       occurred.  */
		    struct tm tm;

		    if (! __localtime_r (&lt, &tm)
			|| ((ltm.tm_sec ^ tm.tm_sec)
			    | (ltm.tm_min ^ tm.tm_min)
			    | (ltm.tm_hour ^ tm.tm_hour)
			    | (ltm.tm_mday ^ tm.tm_mday)
			    | (ltm.tm_mon ^ tm.tm_mon)
			    | (ltm.tm_year ^ tm.tm_year)))
		      break;
		  }

		if (! __gmtime_r (&lt, &gtm))
		  break;

		diff = tm_diff (&ltm, &gtm);
	      }
#endif

	    if (diff < 0)
	      {
		add (1, *p = L_('-'));
		diff = -diff;
	      }
	    else
	      add (1, *p = L_('+'));

	    diff /= 60;
	    DO_NUMBER (4, (diff / 60) * 100 + diff % 60);
	  }

	case L_('\0'):		/* GNU extension: % at end of format.  */
	    --f;
	    /* Fall through.  */
	default:
	  /* Unknown format; output the format, including the '%',
	     since this is most likely the right thing to do if a
	     multibyte string has been misparsed.  */
	bad_format:
	  {
	    int flen;
	    for (flen = 1; f[1 - flen] != L_('%'); flen++)
	      continue;
	    cpy (flen, &f[1 - flen]);
	  }
	  break;
	}
    }

  if (p && maxsize != 0)
    *p = L_('\0');
  return i;
}


#ifdef emacs
/* For Emacs we have a separate interface which corresponds to the normal
   strftime function and does not have the extra information whether the
   TP arguments comes from a `gmtime' call or not.  */
size_t
emacs_strftime (s, maxsize, format, tp)
      char *s;
      size_t maxsize;
      const char *format;
      const struct tm *tp;
{
  return my_strftime (s, maxsize, format, tp, 0);
}
#endif

#if defined _LIBC && !defined COMPILE_WIDE
weak_alias (__strftime_l, strftime_l)
#endif