use portable gmtime

src/time.c

@@ -19,8 +19,7 @@
 #ifndef _WIN32
 #define USE_GMTIME_R      /* use reentrant gmtime_r */
 #endif
-#undef  USE_TIMEGM        /* C99 does not have timegm */
-#define USE_TIMEGM        /* use faster gmtime */
+#undef  USE_TIMEGM        /* define to use systems timegm(3) */
 
 #ifdef USE_GETTIMEOFDAY
 #include <sys/time.h>
@@ -31,22 +30,34 @@
 #endif
 
 #ifndef USE_TIMEGM
-time_t
+#define timegm my_timgm
+
+static unsigned int
+is_leapyear(unsigned int y)
+{
+  return (y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0);
+}
+
+static time_t
 timegm(struct tm *tm)
 {
-  time_t ret;
-  char *tz;
+  static const unsigned int ndays[2][12] = {
+    {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
+    {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
+  };
+  time_t r = 0;
+  int i;
+  unsigned int *nday = (unsigned int*) ndays[is_leapyear(tm->tm_year+1900)];
 
-  tz = getenv("TZ");
-  setenv("TZ", "", 1);
-  tzset();
-  ret = mktime(tm);
-  if (tz)
-    setenv("TZ", tz, 1);
-  else
-    unsetenv("TZ");
-  tzset();
-  return ret;
+  for (i = 70; i < tm->tm_year; ++i)
+    r += is_leapyear(i+1900) ? 366*24*60*60 : 365*24*60*60;
+  for (i = 0; i < tm->tm_mon; ++i)
+    r += nday[i] * 24 * 60 * 60;
+  r += (tm->tm_mday - 1) * 24 * 60 * 60;
+  r += tm->tm_hour * 60 * 60;
+  r += tm->tm_min * 60;
+  r += tm->tm_sec;
+  return r;
 }
 #endif
 
@@ -191,36 +202,6 @@ mrb_time_at(mrb_state *mrb, mrb_value self)
   return mrb_time_make(mrb, mrb_class_ptr(self), f, MRB_TIMEZONE_LOCAL);
 }
 
-#ifdef _WIN32
-static unsigned int
-is_leapyear(unsigned int y)
-{
-  return (y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0);
-}
-
-static time_t
-timegm(struct tm *tm)
-{
-  static const unsigned int ndays[2][12] = {
-    {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
-    {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
-  };
-  time_t r = 0;
-  int i;
-  unsigned int *nday = (unsigned int*) ndays[is_leapyear(tm->tm_year+1900)];
-
-  for (i = 70; i < tm->tm_year; ++i)
-    r += is_leapyear(i+1900) ? 366*24*60*60 : 365*24*60*60;
-  for (i = 0; i < tm->tm_mon; ++i)
-    r += nday[i] * 24 * 60 * 60;
-  r += (tm->tm_mday - 1) * 24 * 60 * 60;
-  r += tm->tm_hour * 60 * 60;
-  r += tm->tm_min * 60;
-  r += tm->tm_sec;
-  return r;
-}
-#endif
-
 static struct mrb_time*
 time_mktime(mrb_state *mrb, mrb_int ayear, mrb_int amonth, mrb_int aday,
 	    mrb_int ahour, mrb_int amin, mrb_int asec, mrb_int ausec,