ceph/src/include/timegm.h

   1 //  (C) Copyright Howard Hinnant
   2 //  (C) Copyright 2010-2011 Vicente J. Botet Escriba
   3 //  Use, modification and distribution are subject to the Boost Software License,
   4 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   5 //  http://www.boost.org/LICENSE_1_0.txt).
   6
   7 //===-------------------------- locale ------------------------------------===//
   8 //
   9 //                     The LLVM Compiler Infrastructure
  10 //
  11 // This file is dual licensed under the MIT and the University of Illinois Open
  12 // Source Licenses. See LICENSE.TXT for details.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 // This code was adapted by Vicente from Howard Hinnant's experimental work
  17 // on chrono i/o to Boost and some functions from libc++/locale to emulate the missing time_get::get()
  18
  19 #ifndef BOOST_CHRONO_IO_TIME_POINT_IO_H
  20 #define BOOST_CHRONO_IO_TIME_POINT_IO_H
  21
  22 #include <time.h>
  23
  24 static int32_t is_leap(int32_t year) {
  25   if(year % 400 == 0)
  26     return 1;
  27   if(year % 100 == 0)
  28     return 0;
  29   if(year % 4 == 0)
  30     return 1;
  31   return 0;
  32 }
  33
  34 static int32_t days_from_0(int32_t year) {
  35   year--;
  36   return 365 * year + (year / 400) - (year/100) + (year / 4);
  37 }
  38
  39 int32_t static days_from_1970(int32_t year) {
  40   static const int days_from_0_to_1970 = days_from_0(1970);
  41   return days_from_0(year) - days_from_0_to_1970;
  42 }
  43
  44 static int32_t days_from_1jan(int32_t year,int32_t month,int32_t day) {
  45   static const int32_t days[2][12] =
  46   {
  47     { 0,31,59,90,120,151,181,212,243,273,304,334},
  48     { 0,31,60,91,121,152,182,213,244,274,305,335}
  49   };
  50
  51   return days[is_leap(year)][month-1] + day - 1;
  52 }
  53
  54 static  time_t internal_timegm(tm const *t) {
  55   int year = t->tm_year + 1900;
  56   int month = t->tm_mon;
  57   if(month > 11)
  58   {
  59     year += month/12;
  60     month %= 12;
  61   }
  62   else if(month < 0)
  63   {
  64     int years_diff = (-month + 11)/12;
  65     year -= years_diff;
  66     month+=12 * years_diff;
  67   }
  68   month++;
  69   int day = t->tm_mday;
  70   int day_of_year = days_from_1jan(year,month,day);
  71   int days_since_epoch = days_from_1970(year) + day_of_year ;
  72
  73   time_t seconds_in_day = 3600 * 24;
  74   time_t result = seconds_in_day * days_since_epoch + 3600 * t->tm_hour + 60 * t->tm_min + t->tm_sec;
  75
  76   return result;
  77 }
  78
  79 #endif