From 9d1d8e5306bfd8e0809685a376a689fc3d8ccda3 Mon Sep 17 00:00:00 2001
From: Reuben Dunnington <reuben.dunnington@gmail.com>
Date: Tue, 22 Aug 2023 13:40:39 -0700
Subject: [PATCH] add win32 impl for oc_clock_time()

---
 src/platform/win32_clock.c | 41 ++++++++++++++++++++++++++++++++++----
 1 file changed, 37 insertions(+), 4 deletions(-)

diff --git a/src/platform/win32_clock.c b/src/platform/win32_clock.c
index 46a1767..2d3a3e8 100644
--- a/src/platform/win32_clock.c
+++ b/src/platform/win32_clock.c
@@ -18,6 +18,8 @@ extern "C"
 
     static u64 __performanceCounterFreq = 0;
 
+    const u64 WIN_EPOCH_TO_UNIX_EPOCH_100NS = 116444736000000000; // number of 100ns from Jan 1, 1601 (windows epoch) to  Jan 1, 1970 (unix epoch)
+
     void oc_clock_init()
     {
         LARGE_INTEGER freq;
@@ -27,11 +29,42 @@ extern "C"
 
     f64 oc_clock_time(oc_clock_kind clock)
     {
-        LARGE_INTEGER counter;
-        QueryPerformanceCounter(&counter);
+        switch(clock)
+        {
+            case OC_CLOCK_MONOTONIC:
+            {
+                LARGE_INTEGER counter;
+                QueryPerformanceCounter(&counter);
 
-        f64 time = __performanceCounterFreq ? (counter.QuadPart / (f64)__performanceCounterFreq) : 0;
-        return (time);
+                f64 time = __performanceCounterFreq ? (counter.QuadPart / (f64)__performanceCounterFreq) : 0;
+                return (time);
+            }
+
+            case OC_CLOCK_UPTIME:
+            {
+                LONGLONG unbiasedTime100Ns;
+                if(QueryUnbiasedInterruptTime(&unbiasedTime100Ns))
+                {
+                    f64 unbiasedTimeSecs = ((f64)unbiasedTime100Ns) / (10 * 1000 * 1000);
+                    return unbiasedTimeSecs;
+                }
+                oc_log_error("OC_CLOCK_UPTIME syscall failed with error: %d", GetLastError());
+                return 0;
+            }
+
+            case OC_CLOCK_DATE:
+            {
+                FILETIME ft;
+                GetSystemTimeAsFileTime(&ft);
+
+                u64 systemTime100Ns = ((u64)ft.dwHighDateTime << 32) | (u64)ft.dwLowDateTime;
+                u64 timestamp100Ns = systemTime100Ns - WIN_EPOCH_TO_UNIX_EPOCH_100NS;
+                f64 timeSecs = ((f64)timestamp100Ns) / (10 * 1000 * 1000);
+                return timeSecs;
+            }
+        }
+
+        return 0.0;
     }
 
 #ifdef __cplusplus
-- 
2.25.1