1 files changed, 88 insertions, 0 deletions
diff --git a/src/timegm.c b/src/timegm.c
new file mode 100644
index 0000000..3a671b1
--- /dev/null
+++ b/src/timegm.c
@@ -0,0 +1,88 @@
+/*
+ * nghttp2 - HTTP/2 C Library
+ *
+ * Copyright (c) 2013 Tatsuhiro Tsujikawa
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include "timegm.h"
+
+#include <inttypes.h>
+
+/* Counter the number of leap year in the range [0, y). The |y| is the
+   year, including century (e.g., 2012) */
+static int count_leap_year(int y) {
+  y -= 1;
+  return y / 4 - y / 100 + y / 400;
+}
+
+/* Based on the algorithm of Python 2.7 calendar.timegm. */
+time_t nghttp2_timegm(struct tm *tm) {
+  int days;
+  int num_leap_year;
+  int64_t t;
+  if (tm->tm_mon > 11) {
+    return -1;
+  }
+  num_leap_year = count_leap_year(tm->tm_year + 1900) - count_leap_year(1970);
+  days = (tm->tm_year - 70) * 365 + num_leap_year + tm->tm_yday;
+  t = ((int64_t)days * 24 + tm->tm_hour) * 3600 + tm->tm_min * 60 + tm->tm_sec;
+
+  if (sizeof(time_t) == 4) {
+    if (t < INT32_MIN || t > INT32_MAX) {
+      return -1;
+    }
+  }
+
+  return (time_t)t;
+}
+
+/* Returns nonzero if the |y| is the leap year. The |y| is the year,
+   including century (e.g., 2012) */
+static int is_leap_year(int y) {
+  return y % 4 == 0 && (y % 100 != 0 || y % 400 == 0);
+}
+
+/* The number of days before ith month begins */
+static int daysum[] = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
+
+time_t nghttp2_timegm_without_yday(struct tm *tm) {
+  int days;
+  int num_leap_year;
+  int64_t t;
+  if (tm->tm_mon > 11) {
+    return -1;
+  }
+  num_leap_year = count_leap_year(tm->tm_year + 1900) - count_leap_year(1970);
+  days = (tm->tm_year - 70) * 365 + num_leap_year + daysum[tm->tm_mon] +
+         tm->tm_mday - 1;
+  if (tm->tm_mon >= 2 && is_leap_year(tm->tm_year + 1900)) {
+    ++days;
+  }
+  t = ((int64_t)days * 24 + tm->tm_hour) * 3600 + tm->tm_min * 60 + tm->tm_sec;
+
+  if (sizeof(time_t) == 4) {
+    if (t < INT32_MIN || t > INT32_MAX) {
+      return -1;
+    }
+  }
+
+  return (time_t)t;
+}