strptime_l.c

Linux下头文件time.h的实现源码

	  break;
	case 'r':
#ifdef _NL_CURRENT
	  if (s.decided != raw)
	    {
	      if (!recursive (_NL_CURRENT (LC_TIME, T_FMT_AMPM)))
		{
		  if (s.decided == loc)
		    return NULL;
		  else
		    rp = rp_backup;
		}
	      else
		{
		  if (s.decided == not &&
		      strcmp (_NL_CURRENT (LC_TIME, T_FMT_AMPM),
			      HERE_T_FMT_AMPM))
		    s.decided = loc;
		  break;
		}
	      s.decided = raw;
	    }
#endif
	  if (!recursive (HERE_T_FMT_AMPM))
	    return NULL;
	  break;
	case 'R':
	  if (!recursive ("%H:%M"))
	    return NULL;
	  break;
	case 's':
	  {
	    /* The number of seconds may be very high so we cannot use
	       the `get_number' macro.  Instead read the number
	       character for character and construct the result while
	       doing this.  */
	    time_t secs = 0;
	    if (*rp < '0' || *rp > '9')
	      /* We need at least one digit.  */
	      return NULL;

	    do
	      {
		secs *= 10;
		secs += *rp++ - '0';
	      }
	    while (*rp >= '0' && *rp <= '9');

	    if (localtime_r (&secs, tm) == NULL)
	      /* Error in function.  */
	      return NULL;
	  }
	  break;
	case 'S':
	  get_number (0, 61, 2);
	  tm->tm_sec = val;
	  break;
	case 'X':
#ifdef _NL_CURRENT
	  if (s.decided != raw)
	    {
	      if (!recursive (_NL_CURRENT (LC_TIME, T_FMT)))
		{
		  if (s.decided == loc)
		    return NULL;
		  else
		    rp = rp_backup;
		}
	      else
		{
		  if (strcmp (_NL_CURRENT (LC_TIME, T_FMT), HERE_T_FMT))
		    s.decided = loc;
		  break;
		}
	      s.decided = raw;
	    }
#endif
	  /* Fall through.  */
	case 'T':
	  if (!recursive (HERE_T_FMT))
	    return NULL;
	  break;
	case 'u':
	  get_number (1, 7, 1);
	  tm->tm_wday = val % 7;
	  s.have_wday = 1;
	  break;
	case 'g':
	  get_number (0, 99, 2);
	  /* XXX This cannot determine any field in TM.  */
	  break;
	case 'G':
	  if (*rp < '0' || *rp > '9')
	    return NULL;
	  /* XXX Ignore the number since we would need some more
	     information to compute a real date.  */
	  do
	    ++rp;
	  while (*rp >= '0' && *rp <= '9');
	  break;
	case 'U':
	  get_number (0, 53, 2);
	  s.week_no = val;
	  s.have_uweek = 1;
	  break;
	case 'W':
	  get_number (0, 53, 2);
	  s.week_no = val;
	  s.have_wweek = 1;
	  break;
	case 'V':
	  get_number (0, 53, 2);
	  /* XXX This cannot determine any field in TM without some
	     information.  */
	  break;
	case 'w':
	  /* Match number of weekday.  */
	  get_number (0, 6, 1);
	  tm->tm_wday = val;
	  s.have_wday = 1;
	  break;
	case 'y':
	match_year_in_century:
	  /* Match year within century.  */
	  get_number (0, 99, 2);
	  /* The "Year 2000: The Millennium Rollover" paper suggests that
	     values in the range 69-99 refer to the twentieth century.  */
	  tm->tm_year = val >= 69 ? val : val + 100;
	  /* Indicate that we want to use the century, if specified.  */
	  s.want_century = 1;
	  s.want_xday = 1;
	  break;
	case 'Y':
	  /* Match year including century number.  */
	  get_number (0, 9999, 4);
	  tm->tm_year = val - 1900;
	  s.want_century = 0;
	  s.want_xday = 1;
	  break;
	case 'Z':
	  /* XXX How to handle this?  */
	  break;
	case 'z':
	  /* We recognize two formats: if two digits are given, these
	     specify hours.  If fours digits are used, minutes are
	     also specified.  */
	  {
	    val = 0;
	    while (*rp == ' ')
	      ++rp;
	    if (*rp != '+' && *rp != '-')
	      return NULL;
	    bool neg = *rp++ == '-';
	    int n = 0;
	    while (n < 4 && *rp >= '0' && *rp <= '9')
	      {
		val = val * 10 + *rp++ - '0';
		++n;
	      }
	    if (n == 2)
	      val *= 100;
	    else if (n != 4)
	      /* Only two or four digits recognized.  */
	      return NULL;
	    else
	      {
		/* We have to convert the minutes into decimal.  */
		if (val % 100 >= 60)
		  return NULL;
		val = (val / 100) * 100 + ((val % 100) * 50) / 30;
	      }
	    if (val > 1200)
	      return NULL;
	    tm->tm_gmtoff = (val * 3600) / 100;
	    if (neg)
	      tm->tm_gmtoff = -tm->tm_gmtoff;
	  }
	  break;
	case 'E':
#ifdef _NL_CURRENT
	  switch (*fmt++)
	    {
	    case 'c':
	      /* Match locale's alternate date and time format.  */
	      if (s.decided != raw)
		{
		  const char *fmt = _NL_CURRENT (LC_TIME, ERA_D_T_FMT);

		  if (*fmt == '\0')
		    fmt = _NL_CURRENT (LC_TIME, D_T_FMT);

		  if (!recursive (fmt))
		    {
		      if (s.decided == loc)
			return NULL;
		      else
			rp = rp_backup;
		    }
		  else
		    {
		      if (strcmp (fmt, HERE_D_T_FMT))
			s.decided = loc;
		      s.want_xday = 1;
		      break;
		    }
		  s.decided = raw;
		}
	      /* The C locale has no era information, so use the
		 normal representation.  */
	      if (!recursive (HERE_D_T_FMT))
		return NULL;
	      s.want_xday = 1;
	      break;
	    case 'C':
	      if (s.decided != raw)
		{
		  if (s.era_cnt >= 0)
		    {
		      era = _nl_select_era_entry (s.era_cnt HELPER_LOCALE_ARG);
		      if (era != NULL && match_string (era->era_name, rp))
			{
			  s.decided = loc;
			  break;
			}
		      else
			return NULL;
		    }

		  num_eras = _NL_CURRENT_WORD (LC_TIME,
					       _NL_TIME_ERA_NUM_ENTRIES);
		  for (s.era_cnt = 0; s.era_cnt < (int) num_eras;
		       ++s.era_cnt, rp = rp_backup)
		    {
		      era = _nl_select_era_entry (s.era_cnt
						  HELPER_LOCALE_ARG);
		      if (era != NULL && match_string (era->era_name, rp))
			{
			  s.decided = loc;
			  break;
			}
		    }
		  if (s.era_cnt != (int) num_eras)
		    break;

		  s.era_cnt = -1;
		  if (s.decided == loc)
		    return NULL;

		  s.decided = raw;
		}
	      /* The C locale has no era information, so use the
		 normal representation.  */
	      goto match_century;
 	    case 'y':
	      if (s.decided != raw)
		{
		  get_number(0, 9999, 4);
		  tm->tm_year = val;
		  s.want_era = 1;
		  s.want_xday = 1;
		  s.want_century = 1;

		  if (s.era_cnt >= 0)
		    {
		      assert (s.decided == loc);

		      era = _nl_select_era_entry (s.era_cnt HELPER_LOCALE_ARG);
		      bool match = false;
		      if (era != NULL)
			{
			  int delta = ((tm->tm_year - era->offset)
				       * era->absolute_direction);
			  match = (delta >= 0
				   && delta < (((int64_t) era->stop_date[0]
						- (int64_t) era->start_date[0])
					       * era->absolute_direction));
			}
		      if (! match)
			return NULL;

		      break;
		    }

		  num_eras = _NL_CURRENT_WORD (LC_TIME,
					       _NL_TIME_ERA_NUM_ENTRIES);
		  for (s.era_cnt = 0; s.era_cnt < (int) num_eras; ++s.era_cnt)
		    {
		      era = _nl_select_era_entry (s.era_cnt
						  HELPER_LOCALE_ARG);
		      if (era != NULL)
			{
			  int delta = ((tm->tm_year - era->offset)
				       * era->absolute_direction);
			  if (delta >= 0
			      && delta < (((int64_t) era->stop_date[0]
					   - (int64_t) era->start_date[0])
					  * era->absolute_direction))
			    {
			      s.decided = loc;
			      break;
			    }
			}
		    }
		  if (s.era_cnt != (int) num_eras)
		    break;

		  s.era_cnt = -1;
		  if (s.decided == loc)
		    return NULL;

		  s.decided = raw;
		}

	      goto match_year_in_century;
	    case 'Y':
	      if (s.decided != raw)
		{
		  num_eras = _NL_CURRENT_WORD (LC_TIME,
					       _NL_TIME_ERA_NUM_ENTRIES);
		  for (s.era_cnt = 0; s.era_cnt < (int) num_eras;
		       ++s.era_cnt, rp = rp_backup)
		    {
		      era = _nl_select_era_entry (s.era_cnt HELPER_LOCALE_ARG);
		      if (era != NULL && recursive (era->era_format))
			break;
		    }
		  if (s.era_cnt == (int) num_eras)
		    {
		      s.era_cnt = -1;
		      if (s.decided == loc)
			return NULL;
		      else
			rp = rp_backup;
		    }
		  else
		    {
		      s.decided = loc;
		      s.era_cnt = -1;
		      break;
		    }

		  s.decided = raw;
		}
	      get_number (0, 9999, 4);
	      tm->tm_year = val - 1900;
	      s.want_century = 0;
	      s.want_xday = 1;
	      break;
	    case 'x':
	      if (s.decided != raw)
		{
		  const char *fmt = _NL_CURRENT (LC_TIME, ERA_D_FMT);

		  if (*fmt == '\0')
		    fmt = _NL_CURRENT (LC_TIME, D_FMT);

		  if (!recursive (fmt))
		    {
		      if (s.decided == loc)
			return NULL;
		      else
			rp = rp_backup;
		    }
		  else
		    {
		      if (strcmp (fmt, HERE_D_FMT))
			s.decided = loc;
		      break;
		    }
		  s.decided = raw;
		}
	      if (!recursive (HERE_D_FMT))
		return NULL;
	      break;
	    case 'X':
	      if (s.decided != raw)
		{
		  const char *fmt = _NL_CURRENT (LC_TIME, ERA_T_FMT);

		  if (*fmt == '\0')
		    fmt = _NL_CURRENT (LC_TIME, T_FMT);

		  if (!recursive (fmt))
		    {
		      if (s.decided == loc)
			return NULL;
		      else
			rp = rp_backup;
		    }
		  else
		    {
		      if (strcmp (fmt, HERE_T_FMT))
			s.decided = loc;
		      break;
		    }
		  s.decided = raw;
		}
	      if (!recursive (HERE_T_FMT))
		return NULL;
	      break;
	    default:
	      return NULL;
	    }
	  break;
#else
	  /* We have no information about the era format.  Just use
	     the normal format.  */
	  if (*fmt != 'c' && *fmt != 'C' && *fmt != 'y' && *fmt != 'Y'
	      && *fmt != 'x' && *fmt != 'X')
	    /* This is an illegal format.  */
	    return NULL;

	  goto start_over;
#endif
	case 'O':
	  switch (*fmt++)
	    {
	    case 'd':
	    case 'e':
	      /* Match day of month using alternate numeric symbols.  */
	      get_alt_number (1, 31, 2);
	      tm->tm_mday = val;
	      s.have_mday = 1;
	      s.want_xday = 1;
	      break;
	    case 'H':
	      /* Match hour in 24-hour clock using alternate numeric
		 symbols.  */
	      get_alt_number (0, 23, 2);
	      tm->tm_hour = val;
	      s.have_I = 0;
	      break;
	    case 'I':
	      /* Match hour in 12-hour clock using alternate numeric
		 symbols.  */
	      get_alt_number (1, 12, 2);
	      tm->tm_hour = val % 12;
	      s.have_I = 1;
	      break;
	    case 'm':
	      /* Match month using alternate numeric symbols.  */
	      get_alt_number (1, 12, 2);
	      tm->tm_mon = val - 1;
	      s.have_mon = 1;
	      s.want_xday = 1;
	      break;
	    case 'M':
	      /* Match minutes using alternate numeric symbols.  */
	      get_alt_number (0, 59, 2);
	      tm->tm_min = val;
	      break;
	    case 'S':
	      /* Match seconds using alternate numeric symbols.  */
	      get_alt_number (0, 61, 2);
	      tm->tm_sec = val;
	      break;
	    case 'U':
	      get_alt_number (0, 53, 2);
	      s.week_no = val;
	      s.have_uweek = 1;
	      break;
	    case 'W':
	      get_alt_number (0, 53, 2);
	      s.week_no = val;
	      s.have_wweek = 1;
	      break;
	    case 'V':
	      get_alt_number (0, 53, 2);
	      /* XXX This cannot determine any field in TM without
		 further information.  */
	      break;
	    case 'w':
	      /* Match number of weekday using alternate numeric symbols.  */
	      get_alt_number (0, 6, 1);
	      tm->tm_wday = val;
	      s.have_wday = 1;
	      break;
	    case 'y':
	      /* Match year within century using alternate numeric symbols.  */
	      get_alt_number (0, 99, 2);
	      tm->tm_year = val >= 69 ? val : val + 100;
	      s.want_xday = 1;
	      break;
	    default:
	      return NULL;
	    }
	  break;
	default:
	  return NULL;
	}
    }

  if (statep != NULL)
    {
      /* Recursive invocation, returning success, so
	 update parent's struct tm and state.  */
      *(struct __strptime_state *) statep = s;
      *tmp = tmb;
      return (char *) rp;
    }

  if (s.have_I && s.is_pm)
    tm->tm_hour += 12;

  if (s.century != -1)
    {
      if (s.want_century)
	tm->tm_year = tm->tm_year % 100 + (s.century - 19) * 100;
      else
	/* Only the century, but not the year.  Strange, but so be it.  */
	tm->tm_year = (s.century - 19) * 100;
    }

  if (s.era_cnt != -1)
    {
      era = _nl_select_era_entry (s.era_cnt HELPER_LOCALE_ARG);
      if (era == NULL)
	return NULL;
      if (s.want_era)
	tm->tm_year = (era->start_date[0]
		       + ((tm->tm_year - era->offset)
			  * era->absolute_direction));
      else
	/* Era start year assumed.  */
	tm->tm_year = era->start_date[0];
    }
  else
    if (s.want_era)
      {
	/* No era found but we have seen an E modifier.  Rectify some
	   values.  */
	if (s.want_century && s.century == -1 && tm->tm_year < 69)
	  tm->tm_year += 100;
      }

  if (s.want_xday && !s.have_wday)
    {
      if ( !(s.have_mon && s.have_mday) && s.have_yday)
	{
	  /* We don't have tm_mon and/or tm_mday, compute them.  */
	  int t_mon = 0;
	  while (__mon_yday[__isleap(1900 + tm->tm_year)][t_mon] <= tm->tm_yday)
	      t_mon++;
	  if (!s.have_mon)
	      tm->tm_mon = t_mon - 1;
	  if (!s.have_mday)
	      tm->tm_mday =
		(tm->tm_yday
		 - __mon_yday[__isleap(1900 + tm->tm_year)][t_mon - 1] + 1);
	  s.have_mon = 1;
	  s.have_mday = 1;
	}
      /* Don't crash in day_of_the_week if tm_mon is uninitialized.  */
      if (s.have_mon || (unsigned) tm->tm_mon <= 11)
	day_of_the_week (tm);
    }

  if (s.want_xday && !s.have_yday && (s.have_mon || (unsigned) tm->tm_mon <= 11))
    day_of_the_year (tm);

  if ((s.have_uweek || s.have_wweek) && s.have_wday)
    {
      int save_wday = tm->tm_wday;
      int save_mday = tm->tm_mday;
      int save_mon = tm->tm_mon;
      int w_offset = s.have_uweek ? 0 : 1;

      tm->tm_mday = 1;
      tm->tm_mon = 0;
      day_of_the_week (tm);
      if (s.have_mday)
	tm->tm_mday = save_mday;
      if (s.have_mon)
	tm->tm_mon = save_mon;

      if (!s.have_yday)
	tm->tm_yday = ((7 - (tm->tm_wday - w_offset)) % 7
		       + (s.week_no - 1) *7
		       + save_wday - w_offset);

      if (!s.have_mday || !s.have_mon)
	{
	  int t_mon = 0;
	  while (__mon_yday[__isleap(1900 + tm->tm_year)][t_mon]
		 <= tm->tm_yday)
	    t_mon++;
	  if (!s.have_mon)
	    tm->tm_mon = t_mon - 1;
	  if (!s.have_mday)
	      tm->tm_mday =
		(tm->tm_yday
		 - __mon_yday[__isleap(1900 + tm->tm_year)][t_mon - 1] + 1);
	}

      tm->tm_wday = save_wday;
    }

  return (char *) rp;
}


char *
strptime (buf, format, tm LOCALE_PARAM)
     const char *buf;
     const char *format;
     struct tm *tm;
     LOCALE_PARAM_DECL
{
  return __strptime_internal (buf, format, tm, NULL LOCALE_ARG);
}

#ifdef _LIBC
weak_alias (__strptime_l, strptime_l)
#endif