timestamp.c

/* Copyright (c) 2019-2020, Michael Santos <michael.santos@gmail.com>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#define _XOPEN_SOURCE 700
#include <time.h>

#include "timestamp.h"

time_t timestamp(const char *s) {
  struct tm tm = {0};

  switch (s[0]) {
  case '@':
    if (strptime(s + 1, "%s", &tm) == NULL)
      return -1;

#if defined(__OpenBSD__)
    tm.tm_isdst = -1;
    return mktime(&tm) + tm.tm_gmtoff;
#endif
    break;

  default:
    if (strptime(s, "%Y-%m-%d %T", &tm) == NULL)
      return -1;

    break;
  }

  tm.tm_isdst = -1;

  return mktime(&tm);
}