Fix for bug 537

jnlib/mischelp.c

@@ -0,0 +1,88 @@
+/* mischelp.c - Miscellaneous helper functions
+ * Copyright (C) 1998, 2000, 2001, 2006 Free Software Foundation, Inc.
+ *
+ * This file is part of JNLIB.
+ *
+ * JNLIB is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * JNLIB is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <config.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "libjnlib-config.h"
+#include "mischelp.h"
+
+/* A dummy function to prevent an empty compilation unit.  Some
+   compilers bail out in this case. */
+time_t
+libjnlib_dummy_mischelp_func (void)
+{
+  return time (NULL);
+}
+
+
+/*
+  timegm() is a GNU function that might not be available everywhere.
+  It's basically the inverse of gmtime() - you give it a struct tm,
+  and get back a time_t.  It differs from mktime() in that it handles
+  the case where the struct tm is UTC and the local environment isn't.
+
+  Note, that this replacement implementaion is not thread-safe!
+
+  Some BSDs don't handle the putenv("foo") case properly, so we use
+  unsetenv if the platform has it to remove environment variables.
+*/
+#ifndef HAVE_TIMEGM
+time_t
+timegm (struct tm *tm)
+{
+  time_t answer;
+  char *zone;
+
+  zone=getenv("TZ");
+  putenv("TZ=UTC");
+  tzset();
+  answer=mktime(tm);
+  if(zone)
+    {
+      static char *old_zone;
+
+      if (!old_zone)
+        {
+          old_zone = malloc(3+strlen(zone)+1);
+          if (old_zone)
+            {
+              strcpy(old_zone,"TZ=");
+              strcat(old_zone,zone);
+            }
+	}
+      if (old_zone)
+        putenv (old_zone);	
+    }
+  else
+#ifdef HAVE_UNSETENV
+    unsetenv("TZ");
+#else
+    putenv("TZ");
+#endif
+
+  tzset();
+  return answer;
+}
+#endif /*!HAVE_TIMEGM*/
+