sdk/lib/crt/time/mktime.c

   1 /*
   2  * COPYRIGHT:   LGPL, See LGPL.txt in the top level directory
   3  * PROJECT:     ReactOS CRT library
   4  * FILE:        lib/sdk/crt/time/mktime.c
   5  * PURPOSE:     Implementation of mktime, _mkgmtime
   6  * PROGRAMERS:  Timo Kreuzer
   7  */
   8 #include <precomp.h>
   9 #include "bitsfixup.h"
  10
  11 #define MAX_32BIT_TIME 0xFFFFFFFFULL
  12
  13 static int g_monthdays[13] = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};
  14
  15 __time64_t
  16 mktime_worker(struct tm * ptm, int utc)
  17 {
  18     struct tm *ptm2;
  19     __time64_t time;
  20     int mons, years, leapyears;
  21     TIME_ZONE_INFORMATION tzi;
  22     DWORD ret;
  23
  24     /* Normalize year and month */
  25     if (ptm->tm_mon < 0)
  26     {
  27         mons = -ptm->tm_mon - 1;
  28         ptm->tm_year -= 1 + mons / 12;
  29         ptm->tm_mon = 11 - (mons % 12);
  30     }
  31     else if (ptm->tm_mon > 11)
  32     {
  33         mons = ptm->tm_mon;
  34         ptm->tm_year += (mons / 12);
  35         ptm->tm_mon = mons % 12;
  36     }
  37
  38     /* Is it inside margins */
  39     if (ptm->tm_year < 70 || ptm->tm_year > 139) // FIXME: max year for 64 bits
  40     {
  41         return -1;
  42     }
  43
  44     years = ptm->tm_year - 70;
  45
  46     /* Number of leapyears passed since 1970 */
  47     leapyears = (years + 1) / 4;
  48
  49     /* Calculate days up to 1st of Jan */
  50     time = years * 365 + leapyears;
  51
  52     /* Calculate days up to 1st of month */
  53     time += g_monthdays[ptm->tm_mon];
  54
  55     /* Check if we need to add a leap day */
  56     if (((years + 2) % 4) == 0)
  57     {
  58         if (ptm->tm_mon > 2)
  59         {
  60             time++;
  61         }
  62     }
  63
  64     time += ptm->tm_mday - 1;
  65
  66     time *= 24;
  67     time += ptm->tm_hour;
  68
  69     time *= 60;
  70     time += ptm->tm_min;
  71
  72     time *= 60;
  73     time += ptm->tm_sec;
  74
  75     if (time < 0)
  76     {
  77         return -1;
  78     }
  79
  80     /* Finally get normalized tm struct */
  81     ptm2 = _gmtime64(&time);
  82     if (!ptm2)
  83     {
  84         return -1;
  85     }
  86     *ptm = *ptm2;
  87
  88     /* Finally adjust by the difference to GMT in seconds */
  89     ret = GetTimeZoneInformation(&tzi);
  90     if (ret != TIME_ZONE_ID_INVALID)
  91     {
  92         time += tzi.Bias * 60;
  93     }
  94
  95     return time;
  96 }
  97
  98 /*    int tm_sec;
  99     int tm_min;
 100     int tm_hour;
 101     int tm_mday;
 102     int tm_mon;
 103     int tm_year;
 104     int tm_wday;
 105     int tm_yday;
 106     int tm_isdst;
 107 */
 108
 109 /**
 110  * \name _mkgmtime
 111  *
 112  */
 113 time_t
 114 _mkgmtime(struct tm *ptm)
 115 {
 116     __time64_t time = mktime_worker(ptm, 1);
 117     return (time_t)((time > MAX_32BIT_TIME) ? -1 : time);
 118 }
 119
 120 time_t
 121 mktime(struct tm *ptm)
 122 {
 123     __time64_t time = mktime_worker(ptm, 0);
 124     return (time_t)((time > MAX_32BIT_TIME) ? -1 : time);
 125 }
 126
 127 __time32_t
 128 _mkgmtime32(struct tm *ptm)
 129 {
 130     __time64_t time = mktime_worker(ptm, 1);
 131     return (__time32_t)((time > MAX_32BIT_TIME) ? -1 : time);
 132 }
 133
 134 __time32_t
 135 _mktime32(struct tm *ptm)
 136 {
 137     __time64_t time = mktime_worker(ptm, 0);
 138     return (__time32_t)((time > MAX_32BIT_TIME) ? -1 : time);
 139 }
 140
 141 __time64_t
 142 _mkgmtime64(struct tm *ptm)
 143 {
 144     return mktime_worker(ptm, 1);
 145 }
 146
 147 __time64_t
 148 _mktime64(struct tm *ptm)
 149 {
 150     return mktime_worker(ptm, 0);
 151 }