From e8d59272d85bcac4a89ff36a190aee09dd7dfac9 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Sat, 31 Dec 2016 07:08:47 +0100
Subject: compat/timer: prevent races in initializing timer resolution

Also,
- don't lose high bits with cast from long long to long on _WIN32.
- reduce #define pollution
---
 compat/timer.hpp | 109 +++++++++++++++++++++++++++++++------------------------
 1 file changed, 61 insertions(+), 48 deletions(-)

(limited to 'compat/timer.hpp')

diff --git a/compat/timer.hpp b/compat/timer.hpp
index b01e5f38..ab1ec6b3 100644
--- a/compat/timer.hpp
+++ b/compat/timer.hpp
@@ -11,49 +11,11 @@
 
 #if defined (_WIN32)
 #   include <windows.h>
-#	ifndef CLOCK_MONOTONIC
-#   	define CLOCK_MONOTONIC -1
-#	endif
-static inline void opentrack_clock_gettime(int, struct timespec* ts)
-{
-    static LARGE_INTEGER freq;
-
-    if (!freq.QuadPart)
-        (void) QueryPerformanceFrequency(&freq);
-
-    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);
-}
-#	define clock_gettime opentrack_clock_gettime
-#else
-#   if defined(__MACH__)
-#       define CLOCK_MONOTONIC 0
-#       include <inttypes.h>
-#       include <mach/mach_time.h>
-static inline void clock_gettime(int, struct timespec* ts)
-{
-    static mach_timebase_info_data_t    sTimebaseInfo;
-    uint64_t state, nsec;
-    if ( sTimebaseInfo.denom == 0 ) {
-        (void) mach_timebase_info(&sTimebaseInfo);
-    }
-    state = mach_absolute_time();
-    nsec = state * sTimebaseInfo.numer / sTimebaseInfo.denom;
-    ts->tv_sec = nsec / 1000000000L;
-    ts->tv_nsec = nsec % 1000000000L;
-}
-#   endif
+#elif defined(__MACH__)
+#   include <inttypes.h>
+#   include <mach/mach_time.h>
 #endif
+
 class Timer
 {
 private:
@@ -64,27 +26,78 @@ private:
     }
     long conv_usecs(const struct timespec& cur) const
     {
-        return long(cur.tv_sec - state.tv_sec) * 1000000L + long(cur.tv_nsec - state.tv_nsec) / 1000l;
+        return (cur.tv_sec - state.tv_sec) * 1000000LL + (cur.tv_nsec - state.tv_nsec) / 1000;
+    }
+#ifdef _WIN32
+    static LARGE_INTEGER otr_get_clock_frequency()
+    {
+        LARGE_INTEGER freq = {};
+        (void) QueryPerformanceFrequency(&freq);
+        return freq;
     }
+    static void otr_clock_gettime(struct 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__)
+    static mach_timebase_info_data_t otr_get_mach_frequency()
+    {
+        mach_timebase_info_data_t timebase_info;
+        (void) mach_timebase_info(&timebase_info);
+        return timebase_info;
+    }
+    static void otr_clock_gettime(struct 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
+
 public:
     Timer()
     {
         start();
     }
+    static inline void wrap_gettime(struct timespec* state)
+    {
+#if defined(_WIN32) || defined(__MACH__)
+        otr_clock_gettime(state);
+#else
+        (void) clock_gettime(CLOCK_MONOTONIC, state);
+#endif
+    }
+
     void start()
     {
-        clock_gettime(CLOCK_MONOTONIC, &state);
+        wrap_gettime(&state);
     }
     long long elapsed_nsecs() const
     {
-        struct timespec cur;
-        clock_gettime(CLOCK_MONOTONIC, &cur);
+        struct timespec cur = {};
+        wrap_gettime(&cur);
         return conv_nsecs(cur);
     }
     long elapsed_usecs() const
     {
-        struct timespec cur;
-        clock_gettime(CLOCK_MONOTONIC, &cur);
+        struct timespec cur = {};
+        wrap_gettime(&cur);
         return long(conv_usecs(cur));
     }
     long elapsed_ms() const
-- 
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