1  /* PO/POT file timestamps.
       2     Copyright (C) 1995-1998, 2000-2003, 2006 Free Software Foundation, Inc.
       3     Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, April 1995.
       4  
       5     This program is free software: you can redistribute it and/or modify
       6     it under the terms of the GNU General Public License as published by
       7     the Free Software Foundation; either version 3 of the License, or
       8     (at your option) any later version.
       9  
      10     This program is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13     GNU General Public License for more details.
      14  
      15     You should have received a copy of the GNU General Public License
      16     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      17  
      18  #ifdef HAVE_CONFIG_H
      19  # include <config.h>
      20  #endif
      21  
      22  /* Specification.  */
      23  #include "po-time.h"
      24  
      25  #include "xvasprintf.h"
      26  
      27  
      28  #define TM_YEAR_ORIGIN 1900
      29  
      30  /* Yield A - B, measured in seconds.  */
      31  static long
      32  difftm (const struct tm *a, const struct tm *b)
      33  {
      34    int ay = a->tm_year + TM_YEAR_ORIGIN - 1;
      35    int by = b->tm_year + TM_YEAR_ORIGIN - 1;
      36    /* Some compilers cannot handle this as a single return statement.  */
      37    long days = (
      38                 /* difference in day of year  */
      39                 a->tm_yday - b->tm_yday
      40                 /* + intervening leap days  */
      41                 + ((ay >> 2) - (by >> 2))
      42                 - (ay / 100 - by / 100)
      43                 + ((ay / 100 >> 2) - (by / 100 >> 2))
      44                 /* + difference in years * 365  */
      45                 + (long) (ay - by) * 365l);
      46  
      47    return 60l * (60l * (24l * days + (a->tm_hour - b->tm_hour))
      48                  + (a->tm_min - b->tm_min))
      49           + (a->tm_sec - b->tm_sec);
      50  }
      51  
      52  
      53  char *
      54  po_strftime (const time_t *tp)
      55  {
      56    struct tm local_time;
      57    char tz_sign;
      58    long tz_min;
      59  
      60    local_time = *localtime (tp);
      61    tz_sign = '+';
      62    tz_min = difftm (&local_time, gmtime (tp)) / 60;
      63    if (tz_min < 0)
      64      {
      65        tz_min = -tz_min;
      66        tz_sign = '-';
      67      }
      68    return xasprintf ("%d-%02d-%02d %02d:%02d%c%02ld%02ld",
      69                      local_time.tm_year + TM_YEAR_ORIGIN,
      70                      local_time.tm_mon + 1,
      71                      local_time.tm_mday,
      72                      local_time.tm_hour,
      73                      local_time.tm_min,
      74                      tz_sign, tz_min / 60, tz_min % 60);
      75  }