localtime.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * Most of this code is in the public domain, so clarified as of
 * June 5, 1996 by Arthur David Olson (arthur_david_olson@nih.gov).
 *
 * All modifications to this code to abstract timezones away from
 * the environment are by Tilghman Lesher, <tlesher@vcch.com>, with
 * the copyright assigned to Digium.
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * Multi-timezone Localtime code
 *
 * The original source from this file may be obtained from ftp://elsie.nci.nih.gov/pub/
 */

/*
** This file is in the public domain, so clarified as of
** 1996-06-05 by Arthur David Olson.
*/

/*
** Leap second handling from Bradley White.
** POSIX-style TZ environment variable handling from Guy Harris.
*/

/* #define DEBUG */

/*LINTLIBRARY*/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 189540 $")

#include <sys/stat.h>
#include <fcntl.h>
#include <float.h>
#ifdef HAVE_INOTIFY
#include <sys/inotify.h>
#endif

#include "private.h"
#include "tzfile.h"

#include "asterisk/lock.h"
#include "asterisk/localtime.h"
#include "asterisk/strings.h"
#include "asterisk/linkedlists.h"
#include "asterisk/utils.h"

#ifndef lint
#ifndef NOID
static char __attribute__((unused)) elsieid[] = "@(#)localtime.c  8.5";
#endif /* !defined NOID */
#endif /* !defined lint */

#ifndef TZ_ABBR_MAX_LEN
#define TZ_ABBR_MAX_LEN 16
#endif /* !defined TZ_ABBR_MAX_LEN */

#ifndef TZ_ABBR_CHAR_SET
#define TZ_ABBR_CHAR_SET \
   "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
#endif /* !defined TZ_ABBR_CHAR_SET */

#ifndef TZ_ABBR_ERR_CHAR
#define TZ_ABBR_ERR_CHAR   '_'
#endif /* !defined TZ_ABBR_ERR_CHAR */

/*
** SunOS 4.1.1 headers lack O_BINARY.
*/

#ifdef O_BINARY
#define OPEN_MODE (O_RDONLY | O_BINARY)
#endif /* defined O_BINARY */
#ifndef O_BINARY
#define OPEN_MODE O_RDONLY
#endif /* !defined O_BINARY */

static const char gmt[] = "GMT";
static const struct timeval WRONG = { 0, 0 };

/*! \note
 * The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
 * We default to US rules as of 1999-08-17.
 * POSIX 1003.1 section 8.1.1 says that the default DST rules are
 * implementation dependent; for historical reasons, US rules are a
 * common default.
 */
#ifndef TZDEFRULESTRING
#define TZDEFRULESTRING ",M4.1.0,M10.5.0"
#endif /* !defined TZDEFDST */

/*!< \brief time type information */
struct ttinfo {            /* time type information */
   long     tt_gmtoff;  /* UTC offset in seconds */
   int      tt_isdst;   /* used to set tm_isdst */
   int      tt_abbrind; /* abbreviation list index */
   int      tt_ttisstd; /* TRUE if transition is std time */
   int      tt_ttisgmt; /* TRUE if transition is UTC */
};

/*! \brief leap second information */
struct lsinfo {            /* leap second information */
   time_t      ls_trans;   /* transition time */
   long     ls_corr; /* correction to apply */
};

#define BIGGEST(a, b)   (((a) > (b)) ? (a) : (b))

#ifdef TZNAME_MAX
#define MY_TZNAME_MAX   TZNAME_MAX
#endif /* defined TZNAME_MAX */
#ifndef TZNAME_MAX
#define MY_TZNAME_MAX   255
#endif /* !defined TZNAME_MAX */
#ifndef TZ_STRLEN_MAX
#define TZ_STRLEN_MAX   255
#endif /* !defined TZ_STRLEN_MAX */

struct state {
   /*! Name of the file that this references */
   char    name[TZ_STRLEN_MAX + 1];
   int      leapcnt;
   int      timecnt;
   int      typecnt;
   int      charcnt;
   int      goback;
   int      goahead;
   time_t      ats[TZ_MAX_TIMES];
   unsigned char  types[TZ_MAX_TIMES];
   struct ttinfo  ttis[TZ_MAX_TYPES];
   char     chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
            (2 * (MY_TZNAME_MAX + 1)))];
   struct lsinfo  lsis[TZ_MAX_LEAPS];
#ifdef HAVE_INOTIFY
   int wd[2];
#else
   time_t  mtime[2];
#endif
   AST_LIST_ENTRY(state) list;
};

struct rule {
   int      r_type;     /* type of rule--see below */
   int      r_day;      /* day number of rule */
   int      r_week;     /* week number of rule */
   int      r_mon;      /* month number of rule */
   long     r_time;     /* transition time of rule */
};

#define JULIAN_DAY      0  /* Jn - Julian day */
#define DAY_OF_YEAR     1  /* n - day of year */
#define MONTH_NTH_DAY_OF_WEEK 2  /* Mm.n.d - month, week, day of week */

/*
** Prototypes for static functions.
*/

static long    detzcode P((const char * codep));
static time_t     detzcode64 P((const char * codep));
static int     differ_by_repeat P((time_t t1, time_t t0));
static const char *  getzname P((const char * strp));
static const char *  getqzname P((const char * strp, const int delim));
static const char *  getnum P((const char * strp, int * nump, int min,
            int max));
static const char *  getsecs P((const char * strp, long * secsp));
static const char *  getoffset P((const char * strp, long * offsetp));
static const char *  getrule P((const char * strp, struct rule * rulep));
static int     gmtload P((struct state * sp));
static struct ast_tm *  gmtsub P((const struct timeval * timep, long offset,
            struct ast_tm * tmp));
static struct ast_tm *  localsub P((const struct timeval * timep, long offset,
            struct ast_tm * tmp, const struct state *sp));
static int     increment_overflow P((int * number, int delta));
static int     leaps_thru_end_of P((int y));
static int     long_increment_overflow P((long * number, int delta));
static int     long_normalize_overflow P((long * tensptr,
            int * unitsptr, const int base));
static int     normalize_overflow P((int * tensptr, int * unitsptr,
            const int base));
static struct timeval   time1 P((struct ast_tm * tmp,
            struct ast_tm * (*funcp) P((const struct timeval *,
            long, struct ast_tm *, const struct state *sp)),
            long offset, const struct state *sp));
static struct timeval   time2 P((struct ast_tm *tmp,
            struct ast_tm * (*funcp) P((const struct timeval *,
            long, struct ast_tm*, const struct state *sp)),
            long offset, int * okayp, const struct state *sp));
static struct timeval   time2sub P((struct ast_tm *tmp,
            struct ast_tm * (*funcp) (const struct timeval *,
            long, struct ast_tm*, const struct state *sp),
            long offset, int * okayp, int do_norm_secs, const struct state *sp));
static struct ast_tm *  timesub P((const struct timeval * timep, long offset,
            const struct state * sp, struct ast_tm * tmp));
static int     tmcomp P((const struct ast_tm * atmp,
            const struct ast_tm * btmp));
static time_t     transtime P((time_t janfirst, int year,
            const struct rule * rulep, long offset));
static int     tzload P((const char * name, struct state * sp,
            int doextend));
static int     tzparse P((const char * name, struct state * sp,
            int lastditch));

static AST_LIST_HEAD_STATIC(zonelist, state);

#ifndef TZ_STRLEN_MAX
#define TZ_STRLEN_MAX 255
#endif /* !defined TZ_STRLEN_MAX */

static pthread_t inotify_thread = AST_PTHREADT_NULL;
static ast_cond_t initialization;
static ast_mutex_t initialization_lock;
#ifdef HAVE_INOTIFY
static int inotify_fd = -1;

static void *inotify_daemon(void *data)
{
   struct {
      struct inotify_event iev;
      char name[FILENAME_MAX + 1];
   } buf;
   ssize_t res;
   struct state *cur;
   struct timespec ten_seconds = { 10, 0 };

   inotify_fd = inotify_init();

   ast_mutex_lock(&initialization_lock);
   ast_cond_signal(&initialization);
   ast_mutex_unlock(&initialization_lock);

   if (inotify_fd < 0) {
      ast_log(LOG_ERROR, "Cannot initialize file notification service: %s (%d)\n", strerror(errno), errno);
      inotify_thread = AST_PTHREADT_NULL;
      return NULL;
   }

   for (;/*ever*/;) {
      /* This read should block, most of the time. */
      if ((res = read(inotify_fd, &buf, sizeof(buf))) < sizeof(buf.iev) && res > 0) {
         /* This should never happen */
         ast_log(LOG_ERROR, "Inotify read less than a full event (%zd < %zd)?!!\n", res, sizeof(buf.iev));
         break;
      } else if (res < 0) {
         if (errno == EINTR || errno == EAGAIN) {
            /* If read fails, then wait a bit, then continue */
            nanosleep(&ten_seconds, NULL);
            continue;
         }
         /* Sanity check -- this should never happen, either */
         ast_log(LOG_ERROR, "Inotify failed: %s\n", strerror(errno));
         break;
      }
      AST_LIST_LOCK(&zonelist);
      AST_LIST_TRAVERSE_SAFE_BEGIN(&zonelist, cur, list) {
         if (cur->wd[0] == buf.iev.wd || cur->wd[1] == buf.iev.wd) {
            AST_LIST_REMOVE_CURRENT(list);
            ast_free(cur);
            break;
         }
      }
      AST_LIST_TRAVERSE_SAFE_END
      AST_LIST_UNLOCK(&zonelist);
   }
   close(inotify_fd);
   inotify_thread = AST_PTHREADT_NULL;
   return NULL;
}

static void add_notify(struct state *sp, const char *path)
{
   if (inotify_thread == AST_PTHREADT_NULL) {
      ast_cond_init(&initialization, NULL);
      ast_mutex_init(&initialization_lock);
      ast_mutex_lock(&initialization_lock);
      if (!(ast_pthread_create_background(&inotify_thread, NULL, inotify_daemon, NULL))) {
         /* Give the thread a chance to initialize */
         ast_cond_wait(&initialization, &initialization_lock);
      } else {
         ast_log(LOG_ERROR, "Unable to start notification thread\n");
         ast_mutex_unlock(&initialization_lock);
         return;
      }
      ast_mutex_unlock(&initialization_lock);
   }

   if (inotify_fd > -1) {
      char fullpath[FILENAME_MAX + 1] = "";
      if (readlink(path, fullpath, sizeof(fullpath) - 1) != -1) {
         /* If file the symlink points to changes */
         sp->wd[1] = inotify_add_watch(inotify_fd, fullpath, IN_ATTRIB | IN_DELETE_SELF | IN_MODIFY | IN_MOVE_SELF | IN_CLOSE_WRITE );
      } else {
         sp->wd[1] = -1;
      }
      /* or if the symlink itself changes (or the real file is here, if path is not a symlink) */
      sp->wd[0] = inotify_add_watch(inotify_fd, path, IN_ATTRIB | IN_DELETE_SELF | IN_MODIFY | IN_MOVE_SELF | IN_CLOSE_WRITE
#ifdef IN_DONT_FOLLOW   /* Only defined in glibc 2.5 and above */
         | IN_DONT_FOLLOW
#endif
      );
   }
}
#else
static void *notify_daemon(void *data)
{
   struct stat st, lst;
   struct state *cur;
   struct timespec sixty_seconds = { 60, 0 };

   ast_mutex_lock(&initialization_lock);
   ast_cond_signal(&initialization);
   ast_mutex_unlock(&initialization_lock);

   for (;/*ever*/;) {
      char     fullname[FILENAME_MAX + 1];

      nanosleep(&sixty_seconds, NULL);
      AST_LIST_LOCK(&zonelist);
      AST_LIST_TRAVERSE_SAFE_BEGIN(&zonelist, cur, list) {
         char *name = cur->name;

         if (name[0] == ':')
            ++name;
         if (name[0] != '/') {
            (void) strcpy(fullname, TZDIR "/");
            (void) strcat(fullname, name);
            name = fullname;
         }
         stat(name, &st);
         lstat(name, &lst);
         if (st.st_mtime > cur->mtime[0] || lst.st_mtime > cur->mtime[1]) {
            AST_LIST_REMOVE_CURRENT(list);
            ast_free(cur);
            continue;
         }
      }
      AST_LIST_TRAVERSE_SAFE_END
      AST_LIST_UNLOCK(&zonelist);
   }
   inotify_thread = AST_PTHREADT_NULL;
   return NULL;
}

static void add_notify(struct state *sp, const char *path)
{
   struct stat st;

   if (inotify_thread == AST_PTHREADT_NULL) {
      ast_cond_init(&initialization, NULL);
      ast_mutex_init(&initialization_lock);
      ast_mutex_lock(&initialization_lock);
      if (!(ast_pthread_create_background(&inotify_thread, NULL, notify_daemon, NULL))) {
         /* Give the thread a chance to initialize */
         ast_cond_wait(&initialization, &initialization_lock);
      }
      ast_mutex_unlock(&initialization_lock);
   }

   stat(path, &st);
   sp->mtime[0] = st.st_mtime;
   lstat(path, &st);
   sp->mtime[1] = st.st_mtime;
}
#endif

/*! \note
** Section 4.12.3 of X3.159-1989 requires that
** Except for the strftime function, these functions [asctime,
** ctime, gmtime, localtime] return values in one of two static
** objects: a broken-down time structure and an array of char.
** Thanks to Paul Eggert for noting this.
*/

static long detzcode(const char * const codep)
{
   long  result;
   int   i;

   result = (codep[0] & 0x80) ? ~0L : 0;
   for (i = 0; i < 4; ++i)
      result = (result << 8) | (codep[i] & 0xff);
   return result;
}

static time_t detzcode64(const char * const codep)
{
   time_t   result;
   int   i;

   result = (codep[0] & 0x80) ?  (~(int_fast64_t) 0) : 0;
   for (i = 0; i < 8; ++i)
      result = result * 256 + (codep[i] & 0xff);
   return result;
}

static int differ_by_repeat(const time_t t1, const time_t t0)
{
   const long long at1 = t1, at0 = t0;
   if (TYPE_INTEGRAL(time_t) &&
      TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
         return 0;
   return at1 - at0 == SECSPERREPEAT;
}

static int tzload(const char *name, struct state * const sp, const int doextend)
{
   const char *      p;
   int         i;
   int         fid;
   int         stored;
   int         nread;
   union {
      struct tzhead  tzhead;
      char     buf[2 * sizeof(struct tzhead) +
               2 * sizeof *sp +
               4 * TZ_MAX_TIMES];
   } u;

   if (name == NULL && (name = TZDEFAULT) == NULL)
      return -1;
   {
      int   doaccess;
      /*
      ** Section 4.9.1 of the C standard says that
      ** "FILENAME_MAX expands to an integral constant expression
      ** that is the size needed for an array of char large enough
      ** to hold the longest file name string that the implementation
      ** guarantees can be opened."
      */
      char     fullname[FILENAME_MAX + 1];

      if (name[0] == ':')
         ++name;
      doaccess = name[0] == '/';
      if (!doaccess) {
         if ((p = TZDIR) == NULL)
            return -1;
         if ((strlen(p) + strlen(name) + 1) >= sizeof fullname)
            return -1;
         (void) strcpy(fullname, p);
         (void) strcat(fullname, "/");
         (void) strcat(fullname, name);
         /*
         ** Set doaccess if '.' (as in "../") shows up in name.
         */
         if (strchr(name, '.') != NULL)
            doaccess = TRUE;
         name = fullname;
      }
      if (doaccess && access(name, R_OK) != 0)
         return -1;
      if ((fid = open(name, OPEN_MODE)) == -1)
         return -1;
      add_notify(sp, name);
   }
   nread = read(fid, u.buf, sizeof u.buf);
   if (close(fid) < 0 || nread <= 0)
      return -1;
   for (stored = 4; stored <= 8; stored *= 2) {
      int      ttisstdcnt;
      int      ttisgmtcnt;

      ttisstdcnt = (int) detzcode(u.tzhead.tzh_ttisstdcnt);
      ttisgmtcnt = (int) detzcode(u.tzhead.tzh_ttisgmtcnt);
      sp->leapcnt = (int) detzcode(u.tzhead.tzh_leapcnt);
      sp->timecnt = (int) detzcode(u.tzhead.tzh_timecnt);
      sp->typecnt = (int) detzcode(u.tzhead.tzh_typecnt);
      sp->charcnt = (int) detzcode(u.tzhead.tzh_charcnt);
      p = u.tzhead.tzh_charcnt + sizeof u.tzhead.tzh_charcnt;
      if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
         sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
         sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
         sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
         (ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
         (ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
            return -1;
      if (nread - (p - u.buf) <
         sp->timecnt * stored +     /* ats */
         sp->timecnt +        /* types */
         sp->typecnt * 6 +    /* ttinfos */
         sp->charcnt +        /* chars */
         sp->leapcnt * (stored + 4) +  /* lsinfos */
         ttisstdcnt +         /* ttisstds */
         ttisgmtcnt)       /* ttisgmts */
            return -1;
      for (i = 0; i < sp->timecnt; ++i) {
         sp->ats[i] = (stored == 4) ?
            detzcode(p) : detzcode64(p);
         p += stored;
      }
      for (i = 0; i < sp->timecnt; ++i) {
         sp->types[i] = (unsigned char) *p++;
         if (sp->types[i] >= sp->typecnt)
            return -1;
      }
      for (i = 0; i < sp->typecnt; ++i) {
         struct ttinfo *   ttisp;

         ttisp = &sp->ttis[i];
         ttisp->tt_gmtoff = detzcode(p);
         p += 4;
         ttisp->tt_isdst = (unsigned char) *p++;
         if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
            return -1;
         ttisp->tt_abbrind = (unsigned char) *p++;
         if (ttisp->tt_abbrind < 0 ||
            ttisp->tt_abbrind > sp->charcnt)
               return -1;
      }
      for (i = 0; i < sp->charcnt; ++i)
         sp->chars[i] = *p++;
      sp->chars[i] = '\0'; /* ensure '\0' at end */
      for (i = 0; i < sp->leapcnt; ++i) {
         struct lsinfo *   lsisp;

         lsisp = &sp->lsis[i];
         lsisp->ls_trans = (stored == 4) ?
            detzcode(p) : detzcode64(p);
         p += stored;
         lsisp->ls_corr = detzcode(p);
         p += 4;
      }
      for (i = 0; i < sp->typecnt; ++i) {
         struct ttinfo *   ttisp;

         ttisp = &sp->ttis[i];
         if (ttisstdcnt == 0)
            ttisp->tt_ttisstd = FALSE;
         else {
            ttisp->tt_ttisstd = *p++;
            if (ttisp->tt_ttisstd != TRUE &&
               ttisp->tt_ttisstd != FALSE)
                  return -1;
         }
      }
      for (i = 0; i < sp->typecnt; ++i) {
         struct ttinfo *   ttisp;

         ttisp = &sp->ttis[i];
         if (ttisgmtcnt == 0)
            ttisp->tt_ttisgmt = FALSE;
         else {
            ttisp->tt_ttisgmt = *p++;
            if (ttisp->tt_ttisgmt != TRUE &&
               ttisp->tt_ttisgmt != FALSE)
                  return -1;
         }
      }
      /*
      ** Out-of-sort ats should mean we're running on a
      ** signed time_t system but using a data file with
      ** unsigned values (or vice versa).
      */
      for (i = 0; i < sp->timecnt - 2; ++i)
         if (sp->ats[i] > sp->ats[i + 1]) {
            ++i;
            if (TYPE_SIGNED(time_t)) {
               /*
               ** Ignore the end (easy).
               */
               sp->timecnt = i;
            } else {
               /*
               ** Ignore the beginning (harder).
               */
               int   j;

               for (j = 0; j + i < sp->timecnt; ++j) {
                  sp->ats[j] = sp->ats[j + i];
                  sp->types[j] = sp->types[j + i];
               }
               sp->timecnt = j;
            }
            break;
         }
      /*
      ** If this is an old file, we're done.
      */
      if (u.tzhead.tzh_version[0] == '\0')
         break;
      nread -= p - u.buf;
      for (i = 0; i < nread; ++i)
         u.buf[i] = p[i];
      /*
      ** If this is a narrow integer time_t system, we're done.
      */
      if (stored >= (int) sizeof(time_t) && TYPE_INTEGRAL(time_t))
         break;
   }
   if (doextend && nread > 2 &&
      u.buf[0] == '\n' && u.buf[nread - 1] == '\n' &&
      sp->typecnt + 2 <= TZ_MAX_TYPES) {
         struct state   ts;
         int   result;

         u.buf[nread - 1] = '\0';
         result = tzparse(&u.buf[1], &ts, FALSE);
         if (result == 0 && ts.typecnt == 2 &&
            sp->charcnt + ts.charcnt <= TZ_MAX_CHARS) {
               for (i = 0; i < 2; ++i)
                  ts.ttis[i].tt_abbrind +=
                     sp->charcnt;
               for (i = 0; i < ts.charcnt; ++i)
                  sp->chars[sp->charcnt++] =
                     ts.chars[i];
               i = 0;
               while (i < ts.timecnt &&
                  ts.ats[i] <=
                  sp->ats[sp->timecnt - 1])
                     ++i;
               while (i < ts.timecnt &&
                   sp->timecnt < TZ_MAX_TIMES) {
                  sp->ats[sp->timecnt] =
                     ts.ats[i];
                  sp->types[sp->timecnt] =
                     sp->typecnt +
                     ts.types[i];
                  ++sp->timecnt;
                  ++i;
               }
               sp->ttis[sp->typecnt++] = ts.ttis[0];
               sp->ttis[sp->typecnt++] = ts.ttis[1];
         }
   }
   i = 2 * YEARSPERREPEAT;
   sp->goback = sp->goahead = sp->timecnt > i;
   sp->goback = sp->goback && sp->types[i] == sp->types[0] &&
      differ_by_repeat(sp->ats[i], sp->ats[0]);
   sp->goahead = sp->goahead &&
      sp->types[sp->timecnt - 1] == sp->types[sp->timecnt - 1 - i] &&
      differ_by_repeat(sp->ats[sp->timecnt - 1],
          sp->ats[sp->timecnt - 1 - i]);
   return 0;
}

static const int  mon_lengths[2][MONSPERYEAR] = {
   { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
   { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
};

static const int  year_lengths[2] = {
   DAYSPERNYEAR, DAYSPERLYEAR
};

/*! \brief
** Given a pointer into a time zone string, scan until a character that is not
** a valid character in a zone name is found. Return a pointer to that
** character.
*/

static const char * getzname(const char *strp)
{
   char  c;

   while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
      c != '+')
         ++strp;
   return strp;
}

/*! \brief
** Given a pointer into an extended time zone string, scan until the ending
** delimiter of the zone name is located. Return a pointer to the delimiter.
**
** As with getzname above, the legal character set is actually quite
** restricted, with other characters producing undefined results.
** We don't do any checking here; checking is done later in common-case code.
*/

static const char * getqzname(const char *strp, const int delim)
{
   int   c;

   while ((c = *strp) != '\0' && c != delim)
      ++strp;
   return strp;
}

/*! \brief
** Given a pointer into a time zone string, extract a number from that string.
** Check that the number is within a specified range; if it is not, return
** NULL.
** Otherwise, return a pointer to the first character not part of the number.
*/

static const char *getnum(const char *strp, int *nump, const int min, const int max)
{
   char  c;
   int   num;

   if (strp == NULL || !is_digit(c = *strp))
      return NULL;
   num = 0;
   do {
      num = num * 10 + (c - '0');
      if (num > max)
         return NULL;   /* illegal value */
      c = *++strp;
   } while (is_digit(c));
   if (num < min)
      return NULL;      /* illegal value */
   *nump = num;
   return strp;
}

/*! \brief
** Given a pointer into a time zone string, extract a number of seconds,
** in hh[:mm[:ss]] form, from the string.
** If any error occurs, return NULL.
** Otherwise, return a pointer to the first character not part of the number
** of seconds.
*/

static const char *getsecs(const char *strp, long * const secsp)
{
   int   num;

   /*
   ** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
   ** "M10.4.6/26", which does not conform to Posix,
   ** but which specifies the equivalent of
   ** ``02:00 on the first Sunday on or after 23 Oct''.
   */
   strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
   if (strp == NULL)
      return NULL;
   *secsp = num * (long) SECSPERHOUR;
   if (*strp == ':') {
      ++strp;
      strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
      if (strp == NULL)
         return NULL;
      *secsp += num * SECSPERMIN;
      if (*strp == ':') {
         ++strp;
         /* `SECSPERMIN' allows for leap seconds. */
         strp = getnum(strp, &num, 0, SECSPERMIN);
         if (strp == NULL)
            return NULL;
         *secsp += num;
      }
   }
   return strp;
}

/*! \brief
** Given a pointer into a time zone string, extract an offset, in
** [+-]hh[:mm[:ss]] form, from the string.
** If any error occurs, return NULL.
** Otherwise, return a pointer to the first character not part of the time.
*/

static const char *getoffset(const char *strp, long *offsetp)
{
   int   neg = 0;

   if (*strp == '-') {
      neg = 1;
      ++strp;
   } else if (*strp == '+')
      ++strp;
   strp = getsecs(strp, offsetp);
   if (strp == NULL)
      return NULL;      /* illegal time */
   if (neg)
      *offsetp = -*offsetp;
   return strp;
}

/*! \brief
** Given a pointer into a time zone string, extract a rule in the form
** date[/time]. See POSIX section 8 for the format of "date" and "time".
** If a valid rule is not found, return NULL.
** Otherwise, return a pointer to the first character not part of the rule.
*/

static const char *getrule(const char *strp, struct rule *rulep)
{
   if (*strp == 'J') {
      /*
      ** Julian day.
      */
      rulep->r_type = JULIAN_DAY;
      ++strp;
      strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
   } else if (*strp == 'M') {
      /*
      ** Month, week, day.
      */
      rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
      ++strp;
      strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
      if (strp == NULL)
         return NULL;
      if (*strp++ != '.')
         return NULL;
      strp = getnum(strp, &rulep->r_week, 1, 5);
      if (strp == NULL)
         return NULL;
      if (*strp++ != '.')
         return NULL;
      strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
   } else if (is_digit(*strp)) {
      /*
      ** Day of year.
      */
      rulep->r_type = DAY_OF_YEAR;
      strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
   } else   return NULL;      /* invalid format */
   if (strp == NULL)
      return NULL;
   if (*strp == '/') {
      /*
      ** Time specified.
      */
      ++strp;
      strp = getsecs(strp, &rulep->r_time);
   } else   rulep->r_time = 2 * SECSPERHOUR; /* default = 2:00:00 */
   return strp;
}

/*! \brief
** Given the Epoch-relative time of January 1, 00:00:00 UTC, in a year, the
** year, a rule, and the offset from UTC at the time that rule takes effect,
** calculate the Epoch-relative time that rule takes effect.
*/

static time_t transtime(const time_t janfirst, const int year, const struct rule *rulep, const long offset)
{
   int   leapyear;
   time_t   value;
   int   i;
   int      d, m1, yy0, yy1, yy2, dow;

   INITIALIZE(value);
   leapyear = isleap(year);
   switch (rulep->r_type) {

   case JULIAN_DAY:
      /*
      ** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
      ** years.
      ** In non-leap years, or if the day number is 59 or less, just
      ** add SECSPERDAY times the day number-1 to the time of
      ** January 1, midnight, to get the day.
      */
      value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
      if (leapyear && rulep->r_day >= 60)
         value += SECSPERDAY;
      break;

   case DAY_OF_YEAR:
      /*
      ** n - day of year.
      ** Just add SECSPERDAY times the day number to the time of
      ** January 1, midnight, to get the day.
      */
      value = janfirst + rulep->r_day * SECSPERDAY;
      break;

   case MONTH_NTH_DAY_OF_WEEK:
      /*
      ** Mm.n.d - nth "dth day" of month m.
      */
      value = janfirst;
      for (i = 0; i < rulep->r_mon - 1; ++i)
         value += mon_lengths[leapyear][i] * SECSPERDAY;

      /*
      ** Use Zeller's Congruence to get day-of-week of first day of
      ** month.
      */
      m1 = (rulep->r_mon + 9) % 12 + 1;
      yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
      yy1 = yy0 / 100;
      yy2 = yy0 % 100;
      dow = ((26 * m1 - 2) / 10 +
         1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
      if (dow < 0)
         dow += DAYSPERWEEK;

      /*
      ** "dow" is the day-of-week of the first day of the month. Get
      ** the day-of-month (zero-origin) of the first "dow" day of the
      ** month.
      */
      d = rulep->r_day - dow;
      if (d < 0)
         d += DAYSPERWEEK;
      for (i = 1; i < rulep->r_week; ++i) {
         if (d + DAYSPERWEEK >=
            mon_lengths[leapyear][rulep->r_mon - 1])
               break;
         d += DAYSPERWEEK;
      }

      /*
      ** "d" is the day-of-month (zero-origin) of the day we want.
      */
      value += d * SECSPERDAY;
      break;
   }

   /*
   ** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
   ** question. To get the Epoch-relative time of the specified local
   ** time on that day, add the transition time and the current offset
   ** from UTC.
   */
   return value + rulep->r_time + offset;
}

/*! \note
** Given a POSIX section 8-style TZ string, fill in the rule tables as
** appropriate.
*/

static int tzparse(const char *name, struct state *sp, const int lastditch)
{
   const char *         stdname;
   const char *         dstname;
   size_t            stdlen;
   size_t            dstlen;
   long           stdoffset;
   long           dstoffset;
   time_t *    atp;
   unsigned char *   typep;
   char *         cp;
   int         load_result;

   INITIALIZE(dstname);
   stdname = name;
   if (lastditch) {
      stdlen = strlen(name);  /* length of standard zone name */
      name += stdlen;
      if (stdlen >= sizeof sp->chars)
         stdlen = (sizeof sp->chars) - 1;
      stdoffset = 0;
   } else {
      if (*name == '<') {
         name++;
         stdname = name;
         name = getqzname(name, '>');
         if (*name != '>')
            return -1;
         stdlen = name - stdname;
         name++;
      } else {
         name = getzname(name);
         stdlen = name - stdname;
      }
      if (*name == '\0')
         return -1;
      name = getoffset(name, &stdoffset);
      if (name == NULL)
         return -1;
   }
   load_result = tzload(TZDEFRULES, sp, FALSE);
   if (load_result != 0)
      sp->leapcnt = 0;     /* so, we're off a little */
   if (*name != '\0') {
      if (*name == '<') {
         dstname = ++name;
         name = getqzname(name, '>');
         if (*name != '>')
            return -1;
         dstlen = name - dstname;
         name++;
      } else {
         dstname = name;
         name = getzname(name);
         dstlen = name - dstname; /* length of DST zone name */
      }
      if (*name != '\0' && *name != ',' && *name != ';') {
         name = getoffset(name, &dstoffset);
         if (name == NULL)
            return -1;
      } else   dstoffset = stdoffset - SECSPERHOUR;
      if (*name == '\0' && load_result != 0)
         name = TZDEFRULESTRING;
      if (*name == ',' || *name == ';') {
         struct rule start;
         struct rule end;
         int   year;
         time_t   janfirst;
         time_t      starttime;
         time_t      endtime;

         ++name;
         if ((name = getrule(name, &start)) == NULL)
            return -1;
         if (*name++ != ',')
            return -1;
         if ((name = getrule(name, &end)) == NULL)
            return -1;
         if (*name != '\0')
            return -1;
         sp->typecnt = 2;  /* standard time and DST */
         /*
         ** Two transitions per year, from EPOCH_YEAR forward.
         */
         sp->ttis[0].tt_gmtoff = -dstoffset;
         sp->ttis[0].tt_isdst = 1;
         sp->ttis[0].tt_abbrind = stdlen + 1;
         sp->ttis[1].tt_gmtoff = -stdoffset;
         sp->ttis[1].tt_isdst = 0;
         sp->ttis[1].tt_abbrind = 0;
         atp = sp->ats;
         typep = sp->types;
         janfirst = 0;
         sp->timecnt = 0;
         for (year = EPOCH_YEAR;
             sp->timecnt + 2 <= TZ_MAX_TIMES;
             ++year) {
               time_t   newfirst;

            starttime = transtime(janfirst, year, &start,
               stdoffset);
            endtime = transtime(janfirst, year, &end,
               dstoffset);
            if (starttime > endtime) {
               *atp++ = endtime;
               *typep++ = 1;  /* DST ends */
               *atp++ = starttime;
               *typep++ = 0;  /* DST begins */
            } else {
               *atp++ = starttime;
               *typep++ = 0;  /* DST begins */
               *atp++ = endtime;
               *typep++ = 1;  /* DST ends */
            }
            sp->timecnt += 2;
            newfirst = janfirst;
            newfirst += year_lengths[isleap(year)] *
               SECSPERDAY;
            if (newfirst <= janfirst)
               break;
            janfirst = newfirst;
         }
      } else {
         long  theirstdoffset;
         long  theirdstoffset;
         long  theiroffset;
         int   isdst;
         int   i;
         int   j;

         if (*name != '\0')
            return -1;
         /*
         ** Initial values of theirstdoffset and theirdstoffset.
         */
         theirstdoffset = 0;
         for (i = 0; i < sp->timecnt; ++i) {
            j = sp->types[i];
            if (!sp->ttis[j].tt_isdst) {
               theirstdoffset =
                  -sp->ttis[j].tt_gmtoff;
               break;
            }
         }
         theirdstoffset = 0;
         for (i = 0; i < sp->timecnt; ++i) {
            j = sp->types[i];
            if (sp->ttis[j].tt_isdst) {
               theirdstoffset =
                  -sp->ttis[j].tt_gmtoff;
               break;
            }
         }
         /*
         ** Initially we're assumed to be in standard time.
         */
         isdst = FALSE;
         theiroffset = theirstdoffset;
         /*
         ** Now juggle transition times and types
         ** tracking offsets as you do.
         */
         for (i = 0; i < sp->timecnt; ++i) {
            j = sp->types[i];
            sp->types[i] = sp->ttis[j].tt_isdst;
            if (sp->ttis[j].tt_ttisgmt) {
               /* No adjustment to transition time */
            } else {
               /*
               ** If summer time is in effect, and the
               ** transition time was not specified as
               ** standard time, add the summer time
               ** offset to the transition time;
               ** otherwise, add the standard time
               ** offset to the transition time.
               */
               /*
               ** Transitions from DST to DDST
               ** will effectively disappear since
               ** POSIX provides for only one DST
               ** offset.
               */
               if (isdst && !sp->ttis[j].tt_ttisstd) {
                  sp->ats[i] += dstoffset -
                     theirdstoffset;
               } else {
                  sp->ats[i] += stdoffset -
                     theirstdoffset;
               }
            }
            theiroffset = -sp->ttis[j].tt_gmtoff;
            if (sp->ttis[j].tt_isdst)
               theirdstoffset = theiroffset;
            else  theirstdoffset = theiroffset;
         }
         /*
         ** Finally, fill in ttis.
         ** ttisstd and ttisgmt need not be handled.
         */
         sp->ttis[0].tt_gmtoff = -stdoffset;
         sp->ttis[0].tt_isdst = FALSE;
         sp->ttis[0].tt_abbrind = 0;
         sp->ttis[1].tt_gmtoff = -dstoffset;
         sp->ttis[1].tt_isdst = TRUE;
         sp->ttis[1].tt_abbrind = stdlen + 1;
         sp->typecnt = 2;
      }
   } else {
      dstlen = 0;
      sp->typecnt = 1;     /* only standard time */
      sp->timecnt = 0;
      sp->ttis[0].tt_gmtoff = -stdoffset;
      sp->ttis[0].tt_isdst = 0;
      sp->ttis[0].tt_abbrind = 0;
   }
   sp->charcnt = stdlen + 1;
   if (dstlen != 0)
      sp->charcnt += dstlen + 1;
   if ((size_t) sp->charcnt > sizeof sp->chars)
      return -1;
   cp = sp->chars;
   (void) strncpy(cp, stdname, stdlen);
   cp += stdlen;
   *cp++ = '\0';
   if (dstlen != 0) {
      (void) strncpy(cp, dstname, dstlen);
      *(cp + dstlen) = '\0';
   }
   return 0;
}

static int gmtload(struct state *sp)
{
   if (tzload(gmt, sp, TRUE) != 0)
      return tzparse(gmt, sp, TRUE);
   else
      return -1;
}

static const struct state *ast_tzset(const char *zone)
{
   struct state *sp;

   if (ast_strlen_zero(zone))
      zone = "/etc/localtime";

   AST_LIST_LOCK(&zonelist);
   AST_LIST_TRAVERSE(&zonelist, sp, list) {
      if (!strcmp(sp->name, zone)) {
         AST_LIST_UNLOCK(&zonelist);
         return sp;
      }
   }
   AST_LIST_UNLOCK(&zonelist);

   if (!(sp = ast_calloc(1, sizeof *sp)))
      return NULL;

   if (tzload(zone, sp, TRUE) != 0) {
      if (zone[0] == ':' || tzparse(zone, sp, FALSE) != 0)
         (void) gmtload(sp);
   }
   ast_copy_string(sp->name, zone, sizeof(sp->name));
   AST_LIST_LOCK(&zonelist);
   AST_LIST_INSERT_TAIL(&zonelist, sp, list);
   AST_LIST_UNLOCK(&zonelist);
   return sp;
}

/*! \note
** The easy way to behave "as if no library function calls" localtime
** is to not call it--so we drop its guts into "localsub", which can be
** freely called. (And no, the PANS doesn't require the above behavior--
** but it *is* desirable.)
**
** The unused offset argument is for the benefit of mktime variants.
*/

static struct ast_tm *localsub(const struct timeval *timep, const long offset, struct ast_tm *tmp, const struct state *sp)
{
   const struct ttinfo *   ttisp;
   int         i;
   struct ast_tm *      result;
   struct timeval t;
   memcpy(&t, timep, sizeof(t));

   if (sp == NULL)
      return gmtsub(timep, offset, tmp);
   if ((sp->goback && t.tv_sec < sp->ats[0]) ||
      (sp->goahead && t.tv_sec > sp->ats[sp->timecnt - 1])) {
         struct timeval newt = t;
         time_t      seconds;
         time_t      tcycles;
         int_fast64_t   icycles;

         if (t.tv_sec < sp->ats[0])
            seconds = sp->ats[0] - t.tv_sec;
         else  seconds = t.tv_sec - sp->ats[sp->timecnt - 1];
         --seconds;
         tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
         ++tcycles;
         icycles = tcycles;
         if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
            return NULL;
         seconds = icycles;
         seconds *= YEARSPERREPEAT;
         seconds *= AVGSECSPERYEAR;
         if (t.tv_sec < sp->ats[0])
            newt.tv_sec += seconds;
         else  newt.tv_sec -= seconds;
         if (newt.tv_sec < sp->ats[0] ||
            newt.tv_sec > sp->ats[sp->timecnt - 1])
               return NULL;   /* "cannot happen" */
         result = localsub(&newt, offset, tmp, sp);
         if (result == tmp) {
            time_t   newy;

            newy = tmp->tm_year;
            if (t.tv_sec < sp->ats[0])
               newy -= icycles * YEARSPERREPEAT;
            else
               newy += icycles * YEARSPERREPEAT;
            tmp->tm_year = newy;
            if (tmp->tm_year != newy)
               return NULL;
         }
         return result;
   }
   if (sp->timecnt == 0 || t.tv_sec < sp->ats[0]) {
      i = 0;
      while (sp->ttis[i].tt_isdst) {
         if (++i >= sp->typecnt) {
            i = 0;
            break;
         }
      }
   } else {
      int   lo = 1;
      int   hi = sp->timecnt;

      while (lo < hi) {
         int   mid = (lo + hi) >> 1;

         if (t.tv_sec < sp->ats[mid])
            hi = mid;
         else
            lo = mid + 1;
      }
      i = (int) sp->types[lo - 1];
   }
   ttisp = &sp->ttis[i];
   /*
   ** To get (wrong) behavior that's compatible with System V Release 2.0
   ** you'd replace the statement below with
   ** t += ttisp->tt_gmtoff;
   ** timesub(&t, 0L, sp, tmp);
   */
   result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
   tmp->tm_isdst = ttisp->tt_isdst;
#ifndef SOLARIS /* Solaris doesn't have this element */
   tmp->tm_gmtoff = ttisp->tt_gmtoff;
#endif
#ifdef TM_ZONE
   tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
#endif /* defined TM_ZONE */
   tmp->tm_usec = timep->tv_usec;
   return result;
}

struct ast_tm *ast_localtime(const struct timeval *timep, struct ast_tm *tmp, const char *zone)
{
   const struct state *sp = ast_tzset(zone);
   memset(tmp, 0, sizeof(*tmp));
   return sp ? localsub(timep, 0L, tmp, sp) : NULL;
}

/*
** This function provides informaton about daylight savings time 
** for the given timezone.  This includes whether it can determine 
** if daylight savings is used for this timezone, the UTC times for 
** when daylight savings transitions, and the offset in seconds from 
** UTC. 
*/

void ast_get_dst_info(const time_t * const timep, int *dst_enabled, time_t *dst_start, time_t *dst_end, int *gmt_off, const char * const zone)
{
   int i;   
   int transition1 = -1;
   int transition2 = -1;
   time_t      seconds;
   int  bounds_exceeded = 0;
   time_t  t = *timep;
   const struct state *sp;
   
   if (NULL == dst_enabled)
      return;
   *dst_enabled = 0;

   if (NULL == dst_start || NULL == dst_end || NULL == gmt_off)
      return;

   *gmt_off = 0; 
   
   sp = ast_tzset(zone);
   if (NULL == sp) 
      return;
   
   /* If the desired time exceeds the bounds of the defined time transitions  
   * then give give up on determining DST info and simply look for gmt offset 
   * This requires that I adjust the given time using increments of Gregorian 
   * repeats to place the time within the defined time transitions in the 
   * timezone structure.  
   */
   if ((sp->goback && t < sp->ats[0]) ||
         (sp->goahead && t > sp->ats[sp->timecnt - 1])) {
      time_t      tcycles;
      int_fast64_t   icycles;

      if (t < sp->ats[0])
         seconds = sp->ats[0] - t;
      else  seconds = t - sp->ats[sp->timecnt - 1];
      --seconds;
      tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
      ++tcycles;
      icycles = tcycles;
      if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
         return;
      seconds = icycles;
      seconds *= YEARSPERREPEAT;
      seconds *= AVGSECSPERYEAR;
      if (t < sp->ats[0])
         t += seconds;
      else
         t -= seconds;
      
      if (t < sp->ats[0] || t > sp->ats[sp->timecnt - 1])
         return;  /* "cannot happen" */

      bounds_exceeded = 1;
   }

   if (sp->timecnt == 0 || t < sp->ats[0]) {
      /* I have no transition times or I'm before time */
      *dst_enabled = 0;
      /* Find where I can get gmtoff */
      i = 0;
      while (sp->ttis[i].tt_isdst)
         if (++i >= sp->typecnt) {
         i = 0;
         break;
         }
         *gmt_off = sp->ttis[i].tt_gmtoff;
         return;
   } 

   for (i = 1; i < sp->timecnt; ++i) {
      if (t < sp->ats[i]) {
         transition1 = sp->types[i - 1];
         transition2 = sp->types[i];
         break;
      } 
   }
   /* if I found transition times that do not bounded the given time and these correspond to 
      or the bounding zones do not reflect a changes in day light savings, then I do not have dst active */
   if (i >= sp->timecnt || 0 > transition1 || 0 > transition2 ||
         (sp->ttis[transition1].tt_isdst == sp->ttis[transition2].tt_isdst)) {
      *dst_enabled = 0;
      *gmt_off     = sp->ttis[sp->types[sp->timecnt -1]].tt_gmtoff;
   } else {
      /* I have valid daylight savings information. */
      if(sp->ttis[transition2].tt_isdst) 
         *gmt_off = sp->ttis[transition1].tt_gmtoff;
      else 
         *gmt_off = sp->ttis[transition2].tt_gmtoff;

      /* If I adjusted the time earlier, indicate that the dst is invalid */
      if (!bounds_exceeded) {
         *dst_enabled = 1;
         /* Determine which of the bounds is the start of daylight savings and which is the end */
         if(sp->ttis[transition2].tt_isdst) {
            *dst_start = sp->ats[i];
            *dst_end = sp->ats[i -1];
         } else {
            *dst_start = sp->ats[i -1];
            *dst_end = sp->ats[i];
         }
      }
   }  
   return;
}

/*
** gmtsub is to gmtime as localsub is to localtime.
*/

static struct ast_tm *gmtsub(const struct timeval *timep, const long offset, struct ast_tm *tmp)
{
   struct ast_tm *   result;
   struct state *sp;

   AST_LIST_LOCK(&zonelist);
   AST_LIST_TRAVERSE(&zonelist, sp, list) {
      if (!strcmp(sp->name, "UTC"))
         break;
   }

   if (!sp) {
      if (!(sp = (struct state *) ast_calloc(1, sizeof *sp)))
         return NULL;
      gmtload(sp);
      AST_LIST_INSERT_TAIL(&zonelist, sp, list);
   }
   AST_LIST_UNLOCK(&zonelist);

   result = timesub(timep, offset, sp, tmp);
#ifdef TM_ZONE
   /*
   ** Could get fancy here and deliver something such as
   ** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
   ** but this is no time for a treasure hunt.
   */
   if (offset != 0)
      tmp->TM_ZONE = "    ";
   else
      tmp->TM_ZONE = sp->chars;
#endif /* defined TM_ZONE */
   return result;
}

/*! \brief
** Return the number of leap years through the end of the given year
** where, to make the math easy, the answer for year zero is defined as zero.
*/

static int leaps_thru_end_of(const int y)
{
   return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
      -(leaps_thru_end_of(-(y + 1)) + 1);
}

static struct ast_tm *timesub(const struct timeval *timep, const long offset, const struct state *sp, struct ast_tm *tmp)
{
   const struct lsinfo *   lp;
   time_t         tdays;
   int         idays;   /* unsigned would be so 2003 */
   long        rem;
   int            y;
   const int *    ip;
   long        corr;
   int         hit;
   int         i;
   long  seconds;


   corr = 0;
   hit = 0;
   i = (sp == NULL) ? 0 : sp->leapcnt;
   while (--i >= 0) {
      lp = &sp->lsis[i];
      if (timep->tv_sec >= lp->ls_trans) {
         if (timep->tv_sec == lp->ls_trans) {
            hit = ((i == 0 && lp->ls_corr > 0) ||
               lp->ls_corr > sp->lsis[i - 1].ls_corr);
            if (hit)
               while (i > 0 &&
                  sp->lsis[i].ls_trans ==
                  sp->lsis[i - 1].ls_trans + 1 &&
                  sp->lsis[i].ls_corr ==
                  sp->lsis[i - 1].ls_corr + 1) {
                     ++hit;
                     --i;
               }
         }
         corr = lp->ls_corr;
         break;
      }
   }
   y = EPOCH_YEAR;
   tdays = timep->tv_sec / SECSPERDAY;
   rem = timep->tv_sec - tdays * SECSPERDAY;
   while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
      int      newy;
      time_t   tdelta;
      int   idelta;
      int   leapdays;

      tdelta = tdays / DAYSPERLYEAR;
      idelta = tdelta;
      if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
         return NULL;
      if (idelta == 0)
         idelta = (tdays < 0) ? -1 : 1;
      newy = y;
      if (increment_overflow(&newy, idelta))
         return NULL;
      leapdays = leaps_thru_end_of(newy - 1) -
         leaps_thru_end_of(y - 1);
      tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
      tdays -= leapdays;
      y = newy;
   }

   seconds = tdays * SECSPERDAY + 0.5;
   tdays = seconds / SECSPERDAY;
   rem += seconds - tdays * SECSPERDAY;

   /*
   ** Given the range, we can now fearlessly cast...
   */
   idays = tdays;
   rem += offset - corr;
   while (rem < 0) {
      rem += SECSPERDAY;
      --idays;
   }
   while (rem >= SECSPERDAY) {
      rem -= SECSPERDAY;
      ++idays;
   }
   while (idays < 0) {
      if (increment_overflow(&y, -1))
         return NULL;
      idays += year_lengths[isleap(y)];
   }
   while (idays >= year_lengths[isleap(y)]) {
      idays -= year_lengths[isleap(y)];
      if (increment_overflow(&y, 1))
         return NULL;
   }
   tmp->tm_year = y;
   if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
      return NULL;
   tmp->tm_yday = idays;
   /*
   ** The "extra" mods below avoid overflow problems.
   */
   tmp->tm_wday = EPOCH_WDAY +
      ((y - EPOCH_YEAR) % DAYSPERWEEK) *
      (DAYSPERNYEAR % DAYSPERWEEK) +
      leaps_thru_end_of(y - 1) -
      leaps_thru_end_of(EPOCH_YEAR - 1) +
      idays;
   tmp->tm_wday %= DAYSPERWEEK;
   if (tmp->tm_wday < 0)
      tmp->tm_wday += DAYSPERWEEK;
   tmp->tm_hour = (int) (rem / SECSPERHOUR);
   rem %= SECSPERHOUR;
   tmp->tm_min = (int) (rem / SECSPERMIN);
   /*
   ** A positive leap second requires a special
   ** representation. This uses "... ??:59:60" et seq.
   */
   tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
   ip = mon_lengths[isleap(y)];
   for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
      idays -= ip[tmp->tm_mon];
   tmp->tm_mday = (int) (idays + 1);
   tmp->tm_isdst = 0;
#ifdef TM_GMTOFF
   tmp->TM_GMTOFF = offset;
#endif /* defined TM_GMTOFF */
   tmp->tm_usec = timep->tv_usec;
   return tmp;
}

/*! \note
** Adapted from code provided by Robert Elz, who writes:
** The "best" way to do mktime I think is based on an idea of Bob
** Kridle's (so its said...) from a long time ago.
** It does a binary search of the time_t space. Since time_t's are
** just 32 bits, its a max of 32 iterations (even at 64 bits it
** would still be very reasonable).
*/

/*! \brief
** Simplified normalize logic courtesy Paul Eggert.
*/

static int increment_overflow(int *number, int delta)
{
   int   number0;

   number0 = *number;
   *number += delta;
   return (*number < number0) != (delta < 0);
}

static int long_increment_overflow(long *number, int delta)
{
   long  number0;

   number0 = *number;
   *number += delta;
   return (*number < number0) != (delta < 0);
}

static int normalize_overflow(int *tensptr, int *unitsptr, const int base)
{
   int   tensdelta;

   tensdelta = (*unitsptr >= 0) ?
      (*unitsptr / base) :
      (-1 - (-1 - *unitsptr) / base);
   *unitsptr -= tensdelta * base;
   return increment_overflow(tensptr, tensdelta);
}

static int long_normalize_overflow(long *tensptr, int *unitsptr, const int base)
{
   int   tensdelta;

   tensdelta = (*unitsptr >= 0) ?
      (*unitsptr / base) :
      (-1 - (-1 - *unitsptr) / base);
   *unitsptr -= tensdelta * base;
   return long_increment_overflow(tensptr, tensdelta);
}

static int tmcomp(const struct ast_tm *atmp, const struct ast_tm *btmp)
{
   int   result;

   if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
      (result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
      (result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
      (result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
      (result = (atmp->tm_min - btmp->tm_min)) == 0 &&
      (result = (atmp->tm_sec - btmp->tm_sec)) == 0)
         result = atmp->tm_usec - btmp->tm_usec;
   return result;
}

static struct timeval time2sub(struct ast_tm *tmp, struct ast_tm * (* const funcp) (const struct timeval *, long, struct ast_tm *, const struct state *), const long offset, int *okayp, const int do_norm_secs, const struct state *sp)
{
   int         dir;
   int         i, j;
   int         saved_seconds;
   long        li;
   time_t         lo;
   time_t         hi;
   long           y;
   struct timeval       newt = { 0, 0 };
   struct timeval       t = { 0, 0 };
   struct ast_tm        yourtm, mytm;

   *okayp = FALSE;
   yourtm = *tmp;
   if (do_norm_secs) {
      if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
         SECSPERMIN))
            return WRONG;
   }
   if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
      return WRONG;
   if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
      return WRONG;
   y = yourtm.tm_year;
   if (long_normalize_overflow(&y, &yourtm.tm_mon, MONSPERYEAR))
      return WRONG;
   /*
   ** Turn y into an actual year number for now.
   ** It is converted back to an offset from TM_YEAR_BASE later.
   */
   if (long_increment_overflow(&y, TM_YEAR_BASE))
      return WRONG;
   while (yourtm.tm_mday <= 0) {
      if (long_increment_overflow(&y, -1))
         return WRONG;
      li = y + (1 < yourtm.tm_mon);
      yourtm.tm_mday += year_lengths[isleap(li)];
   }
   while (yourtm.tm_mday > DAYSPERLYEAR) {
      li = y + (1 < yourtm.tm_mon);
      yourtm.tm_mday -= year_lengths[isleap(li)];
      if (long_increment_overflow(&y, 1))
         return WRONG;
   }
   for ( ; ; ) {
      i = mon_lengths[isleap(y)][yourtm.tm_mon];
      if (yourtm.tm_mday <= i)
         break;
      yourtm.tm_mday -= i;
      if (++yourtm.tm_mon >= MONSPERYEAR) {
         yourtm.tm_mon = 0;
         if (long_increment_overflow(&y, 1))
            return WRONG;
      }
   }
   if (long_increment_overflow(&y, -TM_YEAR_BASE))
      return WRONG;
   yourtm.tm_year = y;
   if (yourtm.tm_year != y)
      return WRONG;
   if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
      saved_seconds = 0;
   else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
      /*
      ** We can't set tm_sec to 0, because that might push the
      ** time below the minimum representable time.
      ** Set tm_sec to 59 instead.
      ** This assumes that the minimum representable time is
      ** not in the same minute that a leap second was deleted from,
      ** which is a safer assumption than using 58 would be.
      */
      if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
         return WRONG;
      saved_seconds = yourtm.tm_sec;
      yourtm.tm_sec = SECSPERMIN - 1;
   } else {
      saved_seconds = yourtm.tm_sec;
      yourtm.tm_sec = 0;
   }
   /*
   ** Do a binary search (this works whatever time_t's type is).
   */
   if (!TYPE_SIGNED(time_t)) {
      lo = 0;
      hi = lo - 1;
   } else if (!TYPE_INTEGRAL(time_t)) {
      if (sizeof(time_t) > sizeof(float))
         hi = (time_t) DBL_MAX;
      else  hi = (time_t) FLT_MAX;
      lo = -hi;
   } else {
      lo = 1;
      for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
         lo *= 2;
      hi = -(lo + 1);
   }
   for ( ; ; ) {
      t.tv_sec = lo / 2 + hi / 2;
      if (t.tv_sec < lo)
         t.tv_sec = lo;
      else if (t.tv_sec > hi)
         t.tv_sec = hi;
      if ((*funcp)(&t, offset, &mytm, sp) == NULL) {
         /*
         ** Assume that t is too extreme to be represented in
         ** a struct ast_tm; arrange things so that it is less
         ** extreme on the next pass.
         */
         dir = (t.tv_sec > 0) ? 1 : -1;
      } else   dir = tmcomp(&mytm, &yourtm);
      if (dir != 0) {
         if (t.tv_sec == lo) {
            ++t.tv_sec;
            if (t.tv_sec <= lo)
               return WRONG;
            ++lo;
         } else if (t.tv_sec == hi) {
            --t.tv_sec;
            if (t.tv_sec >= hi)
               return WRONG;
            --hi;
         }
         if (lo > hi)
            return WRONG;
         if (dir > 0)
            hi = t.tv_sec;
         else  lo = t.tv_sec;
         continue;
      }
      if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
         break;
      /*
      ** Right time, wrong type.
      ** Hunt for right time, right type.
      ** It's okay to guess wrong since the guess
      ** gets checked.
      */
      /*
      ** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
      */
      for (i = sp->typecnt - 1; i >= 0; --i) {
         if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
            continue;
         for (j = sp->typecnt - 1; j >= 0; --j) {
            if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
               continue;
            newt.tv_sec = t.tv_sec + sp->ttis[j].tt_gmtoff -
               sp->ttis[i].tt_gmtoff;
            if ((*funcp)(&newt, offset, &mytm, sp) == NULL)
               continue;
            if (tmcomp(&mytm, &yourtm) != 0)
               continue;
            if (mytm.tm_isdst != yourtm.tm_isdst)
               continue;
            /*
            ** We have a match.
            */
            t = newt;
            goto label;
         }
      }
      return WRONG;
   }
label:
   newt.tv_sec = t.tv_sec + saved_seconds;
   if ((newt.tv_sec < t.tv_sec) != (saved_seconds < 0))
      return WRONG;
   t.tv_sec = newt.tv_sec;
   if ((*funcp)(&t, offset, tmp, sp))
      *okayp = TRUE;
   return t;
}

static struct timeval time2(struct ast_tm *tmp, struct ast_tm * (* const funcp) (const struct timeval *, long, struct ast_tm*, const struct state *sp), const long offset, int *okayp, const struct state *sp)
{
   struct timeval t;

   /*! \note
   ** First try without normalization of seconds
   ** (in case tm_sec contains a value associated with a leap second).
   ** If that fails, try with normalization of seconds.
   */
   t = time2sub(tmp, funcp, offset, okayp, FALSE, sp);
   return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE, sp);
}

static struct timeval time1(struct ast_tm *tmp, struct ast_tm * (* const funcp) (const struct timeval *, long, struct ast_tm *, const struct state *), const long offset, const struct state *sp)
{
   struct timeval       t;
   int         samei, otheri;
   int         sameind, otherind;
   int         i;
   int         nseen;
   int            seen[TZ_MAX_TYPES];
   int            types[TZ_MAX_TYPES];
   int            okay;

   if (tmp->tm_isdst > 1)
      tmp->tm_isdst = 1;
   t = time2(tmp, funcp, offset, &okay, sp);
#ifdef PCTS
   /*
   ** PCTS code courtesy Grant Sullivan.
   */
   if (okay)
      return t;
   if (tmp->tm_isdst < 0)
      tmp->tm_isdst = 0;   /* reset to std and try again */
#endif /* defined PCTS */
#ifndef PCTS
   if (okay || tmp->tm_isdst < 0)
      return t;
#endif /* !defined PCTS */
   /*
   ** We're supposed to assume that somebody took a time of one type
   ** and did some math on it that yielded a "struct ast_tm" that's bad.
   ** We try to divine the type they started from and adjust to the
   ** type they need.
   */
   if (sp == NULL)
      return WRONG;
   for (i = 0; i < sp->typecnt; ++i)
      seen[i] = FALSE;
   nseen = 0;
   for (i = sp->timecnt - 1; i >= 0; --i)
      if (!seen[sp->types[i]]) {
         seen[sp->types[i]] = TRUE;
         types[nseen++] = sp->types[i];
      }
   for (sameind = 0; sameind < nseen; ++sameind) {
      samei = types[sameind];
      if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
         continue;
      for (otherind = 0; otherind < nseen; ++otherind) {
         otheri = types[otherind];
         if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
            continue;
         tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
               sp->ttis[samei].tt_gmtoff;
         tmp->tm_isdst = !tmp->tm_isdst;
         t = time2(tmp, funcp, offset, &okay, sp);
         if (okay)
            return t;
         tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
               sp->ttis[samei].tt_gmtoff;
         tmp->tm_isdst = !tmp->tm_isdst;
      }
   }
   return WRONG;
}

struct timeval ast_mktime(struct ast_tm *tmp, const char *zone)
{
   const struct state *sp;
   if (!(sp = ast_tzset(zone)))
      return WRONG;
   return time1(tmp, localsub, 0L, sp);
}

int ast_strftime(char *buf, size_t len, const char *tmp, const struct ast_tm *tm)
{
   size_t fmtlen = strlen(tmp) + 1;
   char *format = ast_calloc(1, fmtlen), *fptr = format, *newfmt;
   int decimals = -1, i, res;
   long fraction;

   if (!format)
      return -1;
   for (; *tmp; tmp++) {
      if (*tmp == '%') {
         switch (tmp[1]) {
         case '1':
         case '2':
         case '3':
         case '4':
         case '5':
         case '6':
            if (tmp[2] != 'q')
               goto defcase;
            decimals = tmp[1] - '0';
            tmp++;
            /* Fall through */
         case 'q': /* Milliseconds */
            if (decimals == -1)
               decimals = 3;

            /* Juggle some memory to fit the item */
            newfmt = ast_realloc(format, fmtlen + decimals);
            if (!newfmt) {
               ast_free(format);
               return -1;
            }
            fptr = fptr - format + newfmt;
            format = newfmt;
            fmtlen += decimals;

            /* Reduce the fraction of time to the accuracy needed */
            for (i = 6, fraction = tm->tm_usec; i > decimals; i--)
               fraction /= 10;
            fptr += sprintf(fptr, "%0*ld", decimals, fraction);

            /* Reset, in case more than one 'q' specifier exists */
            decimals = -1;
            tmp++;
            break;
         default:
            goto defcase;
         }
      } else
defcase: *fptr++ = *tmp;
   }
   *fptr = '\0';
#undef strftime
   res = (int)strftime(buf, len, format, (struct tm *)tm);
   ast_free(format);
   return res;
}

char *ast_strptime(const char *s, const char *format, struct ast_tm *tm)
{
   struct tm tm2 = { 0, };
   char *res = strptime(s, format, &tm2);
   memcpy(tm, &tm2, sizeof(*tm));
   tm->tm_usec = 0;
   /* strptime(3) doesn't set .tm_isdst correctly, so to force ast_mktime(3)
    * to deal with it correctly, we set it to -1. */
   tm->tm_isdst = -1;
   return res;
}