reactos/lib/sdk/crt/time/timezone.c

   1 /*
   2  * COPYRIGHT:   LGPL, See LGPL.txt in the top level directory
   3  * PROJECT:     ReactOS CRT library
   4  * FILE:        lib/sdk/crt/time/timezone.c
   5  * PURPOSE:     Implementation of time zone functions
   6  * PROGRAMERS:  Timo Kreuzer
   7  */
   8 #include "precomp.h"
   9
  10 char _tz_is_set = 0;
  11
  12 /* buffers must hold 64 characters! */
  13 static char tz_name[64] = "PST";
  14 static char tz_dst_name[64] = "PDT";
  15
  16 long dst_begin = 0;
  17 long dst_end = 0;
  18
  19 /******************************************************************************
  20  * \var _tzname
  21  */
  22 char * _tzname[2] = {
  23   tz_name,
  24   tz_dst_name,
  25 };
  26
  27 /******************************************************************************
  28  * \var _daylight
  29  */
  30 int _daylight = 0;
  31
  32 /******************************************************************************
  33  * \name __p__daylight
  34  * \brief Returns a pointer to the _daylight variable;
  35  */
  36 void *
  37 __p__daylight(void)
  38 {
  39    return &_daylight;
  40 }
  41
  42 /******************************************************************************
  43  * \var _timezone
  44  * \brief
  45  */
  46 long _timezone = 28800;
  47
  48 /******************************************************************************
  49  * \name __p__timezone
  50  * \brief Returns a pointer to the _timezone variable;
  51  */
  52 long *
  53 __p__timezone(void)
  54 {
  55    return &_timezone;
  56 }
  57
  58 /******************************************************************************
  59  * \var _dstbias
  60  * \brief
  61  */
  62 long _dstbias = 0;
  63
  64 /******************************************************************************
  65  * \name __p__dstbias
  66  * \brief Returns a pointer to the _dstbias variable;
  67  */
  68 long *
  69 __p__dstbias(void)
  70 {
  71     return &_dstbias;
  72 }
  73
  74 /******************************************************************************
  75  * \name __p__tzname
  76  * \brief Returns a pointer to the _tzname buffer;
  77  */
  78 char **
  79 __p__tzname(void)
  80 {
  81     return _tzname;
  82 }
  83
  84 /******************************************************************************
  85  * \name _tzset
  86  * \brief Initializes the variables _daylight, _timezone, and _tzname from the
  87  *        "TZ" environment variable if available or else by calling
  88  *        GetTimeZoneInformation.
  89  * \sa http://msdn.microsoft.com/en-us/library/90s5c885.aspx
  90  */
  91 void
  92 _tzset(void)
  93 {
  94     const char * str;
  95
  96     if (_tz_is_set)
  97     {
  98         return;
  99     }
 100
 101     /* Try to read the timezone from environment */
 102     str = getenv("TZ");
 103     if (str && str[0] != 0)
 104     {
 105         long hour = 0, min = 0, sec = 0;
 106         size_t len = strnlen(str, 16);
 107         int sign = 1;
 108
 109         dst_begin = 0;
 110
 111         for (;;)
 112         {
 113             /* Copy timezone name */
 114             strncpy(tz_name, str, 3);
 115             str += 3;
 116             len -= 3;
 117
 118             if (len < 1) break;
 119
 120             if (*str == '+' || *str == '-')
 121             {
 122                 sign = *str == '-' ? -1 : 1;
 123                 str++;
 124                 len--;
 125             }
 126
 127             if (len < 1) break;
 128
 129             hour = atol(str);
 130
 131             while (*str != 0 && *str != ':') str++;
 132             if (*str == 0) break;
 133
 134             min = atol(++str);
 135
 136             while (*str != 0 && *str != ':') str++;
 137             if (*str == 0) break;
 138
 139             sec = atol(++str);
 140
 141             while (*str != 0 && *str <= '9') str++;
 142             if (*str == 0) break;
 143
 144             /* Copy DST name */
 145             strncpy(tz_dst_name, str, 3);
 146
 147             // FIXME: set dst_begin etc
 148
 149             /* We are finished */
 150             break;
 151         }
 152
 153         _timezone = sign * (((hour * 60) + min) * 60 + sec);
 154
 155     }
 156     else
 157     {
 158         TIME_ZONE_INFORMATION tzi;
 159         DWORD ret;
 160
 161         ret = GetTimeZoneInformation(&tzi);
 162         if (ret == TIME_ZONE_ID_INVALID)
 163         {
 164             return;
 165         }
 166
 167         ret = WideCharToMultiByte(CP_ACP,
 168                                   0,
 169                                   tzi.StandardName,
 170                                   -1,
 171                                   tz_name,
 172                                   sizeof(tz_name),
 173                                   NULL,
 174                                   NULL);
 175
 176         ret = WideCharToMultiByte(CP_ACP,
 177                                   0,
 178                                   tzi.DaylightName,
 179                                   -1,
 180                                   tz_dst_name,
 181                                   sizeof(tz_dst_name),
 182                                   NULL,
 183                                   NULL);
 184
 185         _timezone = tzi.Bias * 60;
 186
 187         if (tzi.DaylightDate.wMonth)
 188         {
 189             struct tm _tm;
 190
 191             _daylight = 1;
 192             _dstbias = (tzi.DaylightBias - tzi.StandardBias) * 60;
 193             _tm.tm_year = 70;
 194             _tm.tm_mon = tzi.DaylightDate.wMonth - 1;
 195             _tm.tm_mday = tzi.DaylightDate.wDay;
 196             _tm.tm_hour = tzi.DaylightDate.wHour;
 197             _tm.tm_min = tzi.DaylightDate.wMinute;
 198             _tm.tm_sec = tzi.DaylightDate.wSecond;
 199             dst_begin = (long)_mkgmtime(&_tm);
 200             _tm.tm_mon = tzi.StandardDate.wMonth - 1;
 201             _tm.tm_mday = tzi.StandardDate.wDay;
 202             _tm.tm_hour = tzi.StandardDate.wHour;
 203             _tm.tm_min = tzi.StandardDate.wMinute;
 204             _tm.tm_sec = tzi.StandardDate.wSecond;
 205             dst_end = (long)_mkgmtime(&_tm);
 206         }
 207         else
 208         {
 209             _daylight = 0;
 210             _dstbias = 0;
 211         }
 212
 213     }
 214     _tz_is_set = 1;
 215 }
 216
 217 /*********************************************************************
 218  *              _get_tzname (MSVCRT.@)
 219  */
 220 int CDECL _get_tzname(size_t *ret, char *buf, size_t bufsize, int index)
 221 {
 222     char *str_timezone;
 223
 224     switch (index)
 225     {
 226     case 0:
 227         str_timezone = tz_name;
 228         break;
 229
 230     case 1:
 231         str_timezone = tz_dst_name;
 232         break;
 233
 234     default:
 235         *_errno() = EINVAL;
 236         return EINVAL;
 237     }
 238
 239     if (!ret || (!buf && (bufsize > 0)) || (buf && !bufsize))
 240     {
 241         *_errno() = EINVAL;
 242         return EINVAL;
 243     }
 244
 245     *ret = strlen(str_timezone) + 1;
 246     if(!buf && !bufsize)
 247         return 0;
 248
 249     strncpy(buf, str_timezone, bufsize);
 250     return 0;
 251 }