strftime_l.c

Linux下头文件time.h的实现源码

#endif
  return __strftime_internal (s, maxsize, format, tp, false
			      ut_argument LOCALE_ARG);
}
#ifdef _LIBC
libc_hidden_def (my_strftime)
#endif

static size_t
__strftime_internal (s, maxsize, format, tp, tzset_called ut_argument
		     LOCALE_PARAM)
      CHAR_T *s;
      size_t maxsize;
      const CHAR_T *format;
      const struct tm *tp;
      bool tzset_called;
      ut_argument_spec
      LOCALE_PARAM_DECL
{
#if defined _LIBC && defined USE_IN_EXTENDED_LOCALE_MODEL
  struct locale_data *const current = loc->__locales[LC_TIME];
#endif

  int hour12 = tp->tm_hour;
#ifdef _NL_CURRENT
  /* We cannot make the following values variables since we must delay
     the evaluation of these values until really needed since some
     expressions might not be valid in every situation.  The `struct tm'
     might be generated by a strptime() call that initialized
     only a few elements.  Dereference the pointers only if the format
     requires this.  Then it is ok to fail if the pointers are invalid.  */
# define a_wkday \
  ((const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(ABDAY_1) + tp->tm_wday))
# define f_wkday \
  ((const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(DAY_1) + tp->tm_wday))
# define a_month \
  ((const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(ABMON_1) + tp->tm_mon))
# define f_month \
  ((const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(MON_1) + tp->tm_mon))
# define ampm \
  ((const CHAR_T *) _NL_CURRENT (LC_TIME, tp->tm_hour > 11		      \
				 ? NLW(PM_STR) : NLW(AM_STR)))

# define aw_len STRLEN (a_wkday)
# define am_len STRLEN (a_month)
# define ap_len STRLEN (ampm)
#else
# if !HAVE_STRFTIME
#  define f_wkday (weekday_name[tp->tm_wday])
#  define f_month (month_name[tp->tm_mon])
#  define a_wkday f_wkday
#  define a_month f_month
#  define ampm (L_("AMPM") + 2 * (tp->tm_hour > 11))

  size_t aw_len = 3;
  size_t am_len = 3;
  size_t ap_len = 2;
# endif
#endif
  const char *zone;
  size_t i = 0;
  CHAR_T *p = s;
  const CHAR_T *f;
#if DO_MULTIBYTE && !defined COMPILE_WIDE
  const char *format_end = NULL;
#endif

  zone = NULL;
#if HAVE_TM_ZONE
  /* The POSIX test suite assumes that setting
     the environment variable TZ to a new value before calling strftime()
     will influence the result (the %Z format) even if the information in
     TP is computed with a totally different time zone.
     This is bogus: though POSIX allows bad behavior like this,
     POSIX does not require it.  Do the right thing instead.  */
  zone = (const char *) tp->tm_zone;
#endif
#if HAVE_TZNAME
  if (ut)
    {
      if (! (zone && *zone))
	zone = "GMT";
    }
  else
    {
      /* POSIX.1 requires that local time zone information is used as
	 though strftime called tzset.  */
# if HAVE_TZSET
      if (!tzset_called)
	tzset ();
      tzset_called = true;
# endif
    }
#endif

  if (hour12 > 12)
    hour12 -= 12;
  else
    if (hour12 == 0)
      hour12 = 12;

  for (f = format; *f != '\0'; ++f)
    {
      int pad = 0;		/* Padding for number ('-', '_', or 0).  */
      int modifier;		/* Field modifier ('E', 'O', or 0).  */
      int digits;		/* Max digits for numeric format.  */
      int number_value; 	/* Numeric value to be printed.  */
      int negative_number;	/* 1 if the number is negative.  */
      const CHAR_T *subfmt;
      CHAR_T *bufp;
      CHAR_T buf[1 + (sizeof (int) < sizeof (time_t)
		      ? INT_STRLEN_BOUND (time_t)
		      : INT_STRLEN_BOUND (int))];
      int width = -1;
      int to_lowcase = 0;
      int to_uppcase = 0;
      int change_case = 0;
      int format_char;

#if DO_MULTIBYTE && !defined COMPILE_WIDE
      switch (*f)
	{
	case L_('%'):
	  break;

	case L_('\b'): case L_('\t'): case L_('\n'):
	case L_('\v'): case L_('\f'): case L_('\r'):
	case L_(' '): case L_('!'): case L_('"'): case L_('#'): case L_('&'):
	case L_('\''): case L_('('): case L_(')'): case L_('*'): case L_('+'):
	case L_(','): case L_('-'): case L_('.'): case L_('/'): case L_('0'):
	case L_('1'): case L_('2'): case L_('3'): case L_('4'): case L_('5'):
	case L_('6'): case L_('7'): case L_('8'): case L_('9'): case L_(':'):
	case L_(';'): case L_('<'): case L_('='): case L_('>'): case L_('?'):
	case L_('A'): case L_('B'): case L_('C'): case L_('D'): case L_('E'):
	case L_('F'): case L_('G'): case L_('H'): case L_('I'): case L_('J'):
	case L_('K'): case L_('L'): case L_('M'): case L_('N'): case L_('O'):
	case L_('P'): case L_('Q'): case L_('R'): case L_('S'): case L_('T'):
	case L_('U'): case L_('V'): case L_('W'): case L_('X'): case L_('Y'):
	case L_('Z'): case L_('['): case L_('\\'): case L_(']'): case L_('^'):
	case L_('_'): case L_('a'): case L_('b'): case L_('c'): case L_('d'):
	case L_('e'): case L_('f'): case L_('g'): case L_('h'): case L_('i'):
	case L_('j'): case L_('k'): case L_('l'): case L_('m'): case L_('n'):
	case L_('o'): case L_('p'): case L_('q'): case L_('r'): case L_('s'):
	case L_('t'): case L_('u'): case L_('v'): case L_('w'): case L_('x'):
	case L_('y'): case L_('z'): case L_('{'): case L_('|'): case L_('}'):
	case L_('~'):
	  /* The C Standard requires these 98 characters (plus '%') to
	     be in the basic execution character set.  None of these
	     characters can start a multibyte sequence, so they need
	     not be analyzed further.  */
	  add (1, *p = *f);
	  continue;

	default:
	  /* Copy this multibyte sequence until we reach its end, find
	     an error, or come back to the initial shift state.  */
	  {
	    mbstate_t mbstate = mbstate_zero;
	    size_t len = 0;
	    size_t fsize;

	    if (! format_end)
	      format_end = f + strlen (f) + 1;
	    fsize = format_end - f;

	    do
	      {
		size_t bytes = mbrlen (f + len, fsize - len, &mbstate);

		if (bytes == 0)
		  break;

		if (bytes == (size_t) -2)
		  {
		    len += strlen (f + len);
		    break;
		  }

		if (bytes == (size_t) -1)
		  {
		    len++;
		    break;
		  }

		len += bytes;
	      }
	    while (! mbsinit (&mbstate));

	    cpy (len, f);
	    f += len - 1;
	    continue;
	  }
	}

#else /* ! DO_MULTIBYTE */

      /* Either multibyte encodings are not supported, they are
	 safe for formats, so any non-'%' byte can be copied through,
	 or this is the wide character version.  */
      if (*f != L_('%'))
	{
	  add (1, *p = *f);
	  continue;
	}

#endif /* ! DO_MULTIBYTE */

      /* Check for flags that can modify a format.  */
      while (1)
	{
	  switch (*++f)
	    {
	      /* This influences the number formats.  */
	    case L_('_'):
	    case L_('-'):
	    case L_('0'):
	      pad = *f;
	      continue;

	      /* This changes textual output.  */
	    case L_('^'):
	      to_uppcase = 1;
	      continue;
	    case L_('#'):
	      change_case = 1;
	      continue;

	    default:
	      break;
	    }
	  break;
	}

      /* As a GNU extension we allow to specify the field width.  */
      if (ISDIGIT (*f))
	{
	  width = 0;
	  do
	    {
	      if (width > INT_MAX / 10
		  || (width == INT_MAX / 10 && *f - L_('0') > INT_MAX % 10))
		/* Avoid overflow.  */
		width = INT_MAX;
	      else
		{
		  width *= 10;
		  width += *f - L_('0');
		}
	      ++f;
	    }
	  while (ISDIGIT (*f));
	}

      /* Check for modifiers.  */
      switch (*f)
	{
	case L_('E'):
	case L_('O'):
	  modifier = *f++;
	  break;

	default:
	  modifier = 0;
	  break;
	}

      /* Now do the specified format.  */
      format_char = *f;
      switch (format_char)
	{
#define DO_NUMBER(d, v) \
	  digits = d > width ? d : width;				      \
	  number_value = v; goto do_number
#define DO_NUMBER_SPACEPAD(d, v) \
	  digits = d > width ? d : width;				      \
	  number_value = v; goto do_number_spacepad

	case L_('%'):
	  if (modifier != 0)
	    goto bad_format;
	  add (1, *p = *f);
	  break;

	case L_('a'):
	  if (modifier != 0)
	    goto bad_format;
	  if (change_case)
	    {
	      to_uppcase = 1;
	      to_lowcase = 0;
	    }
#if defined _NL_CURRENT || !HAVE_STRFTIME
	  cpy (aw_len, a_wkday);
	  break;
#else
	  goto underlying_strftime;
#endif

	case 'A':
	  if (modifier != 0)
	    goto bad_format;
	  if (change_case)
	    {
	      to_uppcase = 1;
	      to_lowcase = 0;
	    }
#if defined _NL_CURRENT || !HAVE_STRFTIME
	  cpy (STRLEN (f_wkday), f_wkday);
	  break;
#else
	  goto underlying_strftime;
#endif

	case L_('b'):
	case L_('h'):
	  if (change_case)
	    {
	      to_uppcase = 1;
	      to_lowcase = 0;
	    }
	  if (modifier != 0)
	    goto bad_format;
#if defined _NL_CURRENT || !HAVE_STRFTIME
	  cpy (am_len, a_month);
	  break;
#else
	  goto underlying_strftime;
#endif

	case L_('B'):
	  if (modifier != 0)
	    goto bad_format;
	  if (change_case)
	    {
	      to_uppcase = 1;
	      to_lowcase = 0;
	    }
#if defined _NL_CURRENT || !HAVE_STRFTIME
	  cpy (STRLEN (f_month), f_month);
	  break;
#else
	  goto underlying_strftime;
#endif

	case L_('c'):
	  if (modifier == L_('O'))
	    goto bad_format;
#ifdef _NL_CURRENT
	  if (! (modifier == 'E'
		 && (*(subfmt =
		       (const CHAR_T *) _NL_CURRENT (LC_TIME,
						     NLW(ERA_D_T_FMT)))
		     != '\0')))
	    subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(D_T_FMT));
#else
# if HAVE_STRFTIME
	  goto underlying_strftime;
# else
	  subfmt = L_("%a %b %e %H:%M:%S %Y");
# endif
#endif

	subformat:
	  {
	    CHAR_T *old_start = p;
	    size_t len = __strftime_internal (NULL, (size_t) -1, subfmt,
					      tp, tzset_called ut_argument
					      LOCALE_ARG);
	    add (len, __strftime_internal (p, maxsize - i, subfmt,
					   tp, tzset_called ut_argument
					   LOCALE_ARG));

	    if (to_uppcase)
	      while (old_start < p)
		{
		  *old_start = TOUPPER ((UCHAR_T) *old_start, loc);
		  ++old_start;
		}
	  }
	  break;

#if HAVE_STRFTIME && ! (defined _NL_CURRENT && HAVE_STRUCT_ERA_ENTRY)
	underlying_strftime:
	  {
	    /* The relevant information is available only via the
	       underlying strftime implementation, so use that.  */
	    char ufmt[4];
	    char *u = ufmt;
	    char ubuf[1024]; /* enough for any single format in practice */
	    size_t len;
	    /* Make sure we're calling the actual underlying strftime.
	       In some cases, config.h contains something like
	       "#define strftime rpl_strftime".  */
# ifdef strftime
#  undef strftime
	    size_t strftime ();
# endif

	    *u++ = '%';
	    if (modifier != 0)
	      *u++ = modifier;
	    *u++ = format_char;
	    *u = '\0';
	    len = strftime (ubuf, sizeof ubuf, ufmt, tp);
	    if (len == 0 && ubuf[0] != '\0')
	      return 0;
	    cpy (len, ubuf);
	  }
	  break;
#endif

	case L_('C'):
	  if (modifier == L_('O'))
	    goto bad_format;
	  if (modifier == L_('E'))
	    {
#if HAVE_STRUCT_ERA_ENTRY
	      struct era_entry *era = _nl_get_era_entry (tp HELPER_LOCALE_ARG);
	      if (era)
		{
# ifdef COMPILE_WIDE
		  size_t len = __wcslen (era->era_wname);
		  cpy (len, era->era_wname);
# else
		  size_t len = strlen (era->era_name);
		  cpy (len, era->era_name);
# endif
		  break;
		}
#else
# if HAVE_STRFTIME
	      goto underlying_strftime;
# endif
#endif
	    }

	  {
	    int year = tp->tm_year + TM_YEAR_BASE;
	    DO_NUMBER (1, year / 100 - (year % 100 < 0));
	  }

	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_D_FMT)))
		     != L_('\0'))))
	    subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(D_FMT));
	  goto subformat;
#else
# if HAVE_STRFTIME
	  goto underlying_strftime;
# else
	  /* Fall through.  */
# endif
#endif
	case L_('D'):
	  if (modifier != 0)
	    goto bad_format;
	  subfmt = L_("%m/%d/%y");
	  goto subformat;

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

	  DO_NUMBER (2, tp->tm_mday);

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

	  DO_NUMBER_SPACEPAD (2, tp->tm_mday);

	  /* All numeric formats set DIGITS and NUMBER_VALUE and then
	     jump to one of these two labels.  */

	do_number_spacepad:
	  /* Force `_' flag unless overwritten by `0' or '-' flag.  */
	  if (pad != L_('0') && pad != L_('-'))