reactos/lib/sdk/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
  22     /* Normalize year and month */
  23     if (ptm->tm_mon < 0)
  24     {
  25         mons = -ptm->tm_mon - 1;
  26         ptm->tm_year -= 1 + mons / 12;
  27         ptm->tm_mon = 11 - (mons % 12);
  28     }
  29     else if (ptm->tm_mon > 11)
  30     {
  31         mons = ptm->tm_mon;
  32         ptm->tm_year += (mons / 12);
  33         ptm->tm_mon = mons % 12;
  34     }
  35
  36     /* Is it inside margins */
  37     if (ptm->tm_year < 70 || ptm->tm_year > 139) // FIXME: max year for 64 bits
  38     {
  39         return -1;
  40     }
  41
  42     years = ptm->tm_year - 70;
  43
  44     /* Number of leapyears passed since 1970 */
  45     leapyears = (years + 1) / 4;
  46
  47     /* Calculate days up to 1st of Jan */
  48     time = years * 365 + leapyears;
  49
  50     /* Calculate days up to 1st of month */
  51     time += g_monthdays[ptm->tm_mon];
  52
  53     /* Check if we need to add a leap day */
  54     if (((years + 2) % 4) == 0)
  55     {
  56         if (ptm->tm_mon > 2)
  57         {
  58             time++;
  59         }
  60     }
  61
  62     time += ptm->tm_mday - 1;
  63
  64     time *= 24;
  65     time += ptm->tm_hour;
  66
  67     time *= 60;
  68     time += ptm->tm_min;
  69
  70     time *= 60;
  71     time += ptm->tm_sec;
  72
  73     if (time < 0)
  74     {
  75         return -1;
  76     }
  77
  78     /* Finally get normalized tm struct */
  79     ptm2 = _gmtime64(&time);
  80     if (!ptm2)
  81     {
  82         return -1;
  83     }
  84     *ptm = *ptm2;
  85
  86     /* Finally adjust by the difference to GMT in seconds */
  87     time += _timezone;
  88
  89     return time;
  90 }
  91
  92 /*    int tm_sec;
  93     int tm_min;
  94     int tm_hour;
  95     int tm_mday;
  96     int tm_mon;
  97     int tm_year;
  98     int tm_wday;
  99     int tm_yday;
 100     int tm_isdst;
 101 */
 102
 103 /**
 104  * \name _mkgmtime
 105  *
 106  */
 107 time_t
 108 _mkgmtime(struct tm *ptm)
 109 {
 110     time_t time = mktime_worker(ptm, 1);
 111     return (time > MAX_32BIT_TIME) ? -1 : time;
 112 }
 113
 114 time_t
 115 mktime(struct tm *ptm)
 116 {
 117     time_t time = mktime_worker(ptm, 0);
 118     return (time > MAX_32BIT_TIME) ? -1 : time;
 119 }
 120
 121 __time32_t
 122 _mkgmtime32(struct tm *ptm)
 123 {
 124     time_t time = mktime_worker(ptm, 1);
 125     return (time > MAX_32BIT_TIME) ? -1 : time;
 126 }
 127
 128 __time32_t
 129 _mktime32(struct tm *ptm)
 130 {
 131     time_t time = mktime_worker(ptm, 0);
 132     return (time > MAX_32BIT_TIME) ? -1 : time;
 133 }
 134
 135 __time64_t
 136 _mkgmtime64(struct tm *ptm)
 137 {
 138     return mktime_worker(ptm, 1);
 139 }
 140
 141 __time64_t
 142 _mktime64(struct tm *ptm)
 143 {
 144     return mktime_worker(ptm, 0);
 145 }