1 files changed, 120 insertions, 0 deletions
diff --git a/hrtime.h b/hrtime.h
new file mode 100644
index 0000000000..4dc699a9b6
--- /dev/null
+++ b/hrtime.h
@@ -0,0 +1,120 @@
+#ifndef RB_HRTIME_H
+#define RB_HRTIME_H
+#include "ruby/ruby.h"
+#include <time.h>
+#if defined(HAVE_SYS_TIME_H)
+#  include <sys/time.h>
+#endif
+
+/*
+ * Hi-res monotonic clock.  It is currently nsec resolution, which has over
+ * 500 years of range.
+ *
+ * TBD: Is nsec even necessary? usec resolution seems enough for userspace
+ * and it'll be suitable for use with devices lasting over 500,000 years
+ * (maybe some devices designed for long-term space travel)
+ */
+#define RB_HRTIME_PER_USEC ((rb_hrtime_t)1000)
+#define RB_HRTIME_PER_MSEC (RB_HRTIME_PER_USEC * (rb_hrtime_t)1000)
+#define RB_HRTIME_PER_SEC  (RB_HRTIME_PER_MSEC * (rb_hrtime_t)1000)
+#define RB_HRTIME_MAX      UINT64_MAX
+
+/*
+ * Lets try to support time travelers.  Lets assume anybody with a time machine
+ * also has access to a modern gcc or clang with 128-bit int support
+ */
+#ifdef MY_RUBY_BUILD_MAY_TIME_TRAVEL
+typedef int128_t rb_hrtime_t;
+#else
+typedef uint64_t rb_hrtime_t;
+#endif
+
+/* thread.c */
+rb_hrtime_t rb_hrtime_now(void);
+
+static inline rb_hrtime_t
+rb_hrtime_mul(rb_hrtime_t a, rb_hrtime_t b)
+{
+    rb_hrtime_t c;
+
+#ifdef HAVE_BUILTIN___BUILTIN_MUL_OVERFLOW
+    if (__builtin_mul_overflow(a, b, &c))
+        return RB_HRTIME_MAX;
+#else
+    if (b != 0 && b > RB_HRTIME_MAX / b) /* overflow */
+        return RB_HRTIME_MAX;
+    c = a * b;
+#endif
+    return c;
+}
+
+static inline rb_hrtime_t
+rb_hrtime_add(rb_hrtime_t a, rb_hrtime_t b)
+{
+    rb_hrtime_t c;
+
+#ifdef HAVE_BUILTIN___BUILTIN_ADD_OVERFLOW
+    if (__builtin_add_overflow(a, b, &c))
+        return RB_HRTIME_MAX;
+#else
+    c = a + b;
+    if (c < a) /* overflow */
+        return RB_HRTIME_MAX;
+#endif
+    return c;
+}
+
+static inline rb_hrtime_t
+rb_timeval2hrtime(const struct timeval *tv)
+{
+    rb_hrtime_t s = rb_hrtime_mul((rb_hrtime_t)tv->tv_sec, RB_HRTIME_PER_SEC);
+    rb_hrtime_t u = rb_hrtime_mul((rb_hrtime_t)tv->tv_usec, RB_HRTIME_PER_USEC);
+
+    return rb_hrtime_add(s, u);
+}
+
+static inline rb_hrtime_t
+rb_timespec2hrtime(const struct timespec *ts)
+{
+    rb_hrtime_t s = rb_hrtime_mul((rb_hrtime_t)ts->tv_sec, RB_HRTIME_PER_SEC);
+
+    return rb_hrtime_add(s, (rb_hrtime_t)ts->tv_nsec);
+}
+
+static inline rb_hrtime_t
+rb_msec2hrtime(unsigned long msec)
+{
+    return rb_hrtime_mul((rb_hrtime_t)msec, RB_HRTIME_PER_MSEC);
+}
+
+static inline rb_hrtime_t
+rb_sec2hrtime(time_t sec)
+{
+    if (sec <= 0) return 0;
+
+    return rb_hrtime_mul((rb_hrtime_t)sec, RB_HRTIME_PER_SEC);
+}
+
+static inline struct timespec *
+rb_hrtime2timespec(struct timespec *ts, const rb_hrtime_t *hrt)
+{
+    if (hrt) {
+        ts->tv_sec = *hrt / RB_HRTIME_PER_SEC;
+        ts->tv_nsec = (int32_t)(*hrt % RB_HRTIME_PER_SEC);
+        return ts;
+    }
+    return 0;
+}
+
+static inline struct timeval *
+rb_hrtime2timeval(struct timeval *tv, const rb_hrtime_t *hrt)
+{
+    if (hrt) {
+        tv->tv_sec = *hrt / RB_HRTIME_PER_SEC;
+        tv->tv_usec = (int32_t)((*hrt % RB_HRTIME_PER_SEC)/RB_HRTIME_PER_USEC);
+
+        return tv;
+    }
+    return 0;
+}
+#endif /* RB_HRTIME_H */