From 36c7c208191a0fd34cf48bdfb4af66b4ab0ec594 Mon Sep 17 00:00:00 2001
From: Jay Berkenbilt <ejb@ql.org>
Date: Sat, 17 Apr 2021 18:12:55 -0400
Subject: Fix timezone portability issue (fixes #515)

---
 libqpdf/QUtil.cc              | 13 ++++++++++++-
 libqpdf/qpdf/qpdf-config.h.in |  6 ++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

(limited to 'libqpdf')

diff --git a/libqpdf/QUtil.cc b/libqpdf/QUtil.cc
index 17b163f5..f45468a0 100644
--- a/libqpdf/QUtil.cc
+++ b/libqpdf/QUtil.cc
@@ -889,6 +889,7 @@ QUtil::get_current_qpdf_time()
                     static_cast<int>(ltime.wHour),
                     static_cast<int>(ltime.wMinute),
                     static_cast<int>(ltime.wSecond),
+                    // tzinfo.Bias is minutes before UTC
                     static_cast<int>(tzinfo.Bias));
 #else
     struct tm ltime;
@@ -898,6 +899,16 @@ QUtil::get_current_qpdf_time()
     localtime_r(&now, &ltime);
 #else
     ltime = *localtime(&now);
+#endif
+#if HAVE_TM_GMTOFF
+    // tm_gmtoff is seconds after UTC
+    int tzoff = -static_cast<int>(ltime.tm_gmtoff / 60);
+#elif HAVE_EXTERN_LONG_TIMEZONE
+    // timezone is seconds before UTC, not adjusted for daylight saving time
+    int tzoff = static_cast<int>(timezone / 60);
+#else
+    // Don't know how to get timezone on this platform
+    int tzoff = 0;
 #endif
     return QPDFTime(static_cast<int>(ltime.tm_year + 1900),
                     static_cast<int>(ltime.tm_mon + 1),
@@ -905,7 +916,7 @@ QUtil::get_current_qpdf_time()
                     static_cast<int>(ltime.tm_hour),
                     static_cast<int>(ltime.tm_min),
                     static_cast<int>(ltime.tm_sec),
-                    static_cast<int>(timezone / 60));
+                    tzoff);
 #endif
 }
 
diff --git a/libqpdf/qpdf/qpdf-config.h.in b/libqpdf/qpdf/qpdf-config.h.in
index 78ebc86d..d0e42fbd 100644
--- a/libqpdf/qpdf/qpdf-config.h.in
+++ b/libqpdf/qpdf/qpdf-config.h.in
@@ -12,6 +12,9 @@
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #undef HAVE_DLFCN_H
 
+/* Whether extern long timezone is available */
+#undef HAVE_EXTERN_LONG_TIMEZONE
+
 /* Define to 1 if fseeko (and presumably ftello) exists and is declared. */
 #undef HAVE_FSEEKO
 
@@ -51,6 +54,9 @@
 /* Define to 1 if you have the <sys/types.h> header file. */
 #undef HAVE_SYS_TYPES_H
 
+/* Whether struct tm has tm_gmtoff */
+#undef HAVE_TM_GMTOFF
+
 /* Define to 1 if you have the <unistd.h> header file. */
 #undef HAVE_UNISTD_H
 
-- 
cgit v1.2.3-54-g00ecf