1 files changed, 119 insertions, 0 deletions
diff --git a/compat/timer.cpp b/compat/timer.cpp
new file mode 100644
index 00000000..9ab0f721
--- /dev/null
+++ b/compat/timer.cpp
@@ -0,0 +1,119 @@
+/* Copyright (c) 2014-2015, Stanislaw Halik <sthalik@misaki.pl>
+
+ * Permission to use, copy, modify, and/or distribute this
+ * software for any purpose with or without fee is hereby granted,
+ * provided that the above copyright notice and this permission
+ * notice appear in all copies.
+ */
+
+#pragma once
+
+#include "timer.hpp"
+
+Timer::Timer()
+{
+    start();
+}
+
+void Timer::start()
+{
+    wrap_gettime(&state);
+}
+
+// common
+
+void Timer::wrap_gettime(timespec* state)
+{
+#if defined(_WIN32) || defined(__MACH__)
+    otr_clock_gettime(state);
+#else
+    (void) clock_gettime(CLOCK_MONOTONIC, state);
+#endif
+}
+
+// nanoseconds
+
+long long Timer::elapsed_nsecs() const
+{
+    struct timespec cur = {};
+    wrap_gettime(&cur);
+    return conv_nsecs(cur);
+}
+
+long long Timer::conv_nsecs(const timespec& cur) const
+{
+    // this can and will overflow
+    return (cur.tv_sec - state.tv_sec) * 1000000000LL + (cur.tv_nsec - state.tv_nsec);
+}
+
+// microseconds
+
+double Timer::elapsed_usecs() const
+{
+    struct timespec cur = {};
+    wrap_gettime(&cur);
+    const long long nsecs = conv_nsecs(cur);
+    return nsecs * 1e-3;
+}
+
+// milliseconds
+
+double Timer::elapsed_ms() const
+{
+    return elapsed_usecs() / 1000.;
+}
+
+double Timer::elapsed_seconds() const
+{
+    return double(elapsed_nsecs() * 1e-9L);
+}
+
+// --
+// platform-specific code starts here
+// --
+
+#if defined _WIN32
+LARGE_INTEGER Timer::otr_get_clock_frequency()
+{
+    LARGE_INTEGER freq = {};
+    (void) QueryPerformanceFrequency(&freq);
+    return freq;
+}
+
+void Timer::otr_clock_gettime(timespec* ts)
+{
+    static LARGE_INTEGER freq = otr_get_clock_frequency();
+
+    LARGE_INTEGER d;
+
+    (void) QueryPerformanceCounter(&d);
+
+    using ll = long long;
+    using ld = long double;
+    const long long part = ll(d.QuadPart / ld(freq.QuadPart) * 1000000000.L);
+    using t_s = decltype(ts->tv_sec);
+    using t_ns = decltype(ts->tv_nsec);
+
+    ts->tv_sec = t_s(part / 1000000000LL);
+    ts->tv_nsec = t_ns(part % 1000000000LL);
+}
+
+#elif defined __MACH__
+mach_timebase_info_data_t Timer::otr_get_mach_frequency()
+{
+    mach_timebase_info_data_t timebase_info;
+    (void) mach_timebase_info(&timebase_info);
+    return timebase_info;
+}
+
+double Timer::otr_clock_gettime(timespec* ts)
+{
+    static mach_timebase_info_data_t timebase_info = otr_get_mach_frequency();
+    uint64_t state, nsec;
+    state = mach_absolute_time();
+    nsec = state * timebase_info.numer / timebase_info.denom;
+    ts->tv_sec = nsec / 1000000000L;
+    ts->tv_nsec = nsec % 1000000000L;
+}
+
+#endif