Parallelize

src/clock.c

@@ -0,0 +1,102 @@
+/*
+ * This is free and unencumbered software released into the public domain.
+ *
+ * Anyone is free to copy, modify, publish, use, compile, sell, or
+ * distribute this software, either in source code form or as a compiled
+ * binary, for any purpose, commercial or non-commercial, and by any
+ * means.
+ *
+ * In jurisdictions that recognize copyright laws, the author or authors
+ * of this software dedicate any and all copyright interest in the
+ * software to the public domain. We make this dedication for the benefit
+ * of the public at large and to the detriment of our heirs and
+ * successors. We intend this dedication to be an overt act of
+ * relinquishment in perpetuity of all present and future rights to this
+ * software under copyright law.
+ *
+ * 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 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.
+ *
+ * For more information, please refer to <http://unlicense.org/>
+ */
+
+#include "clock.h"
+
+#ifdef _WIN32
+#define WIN32_MEAN_AND_LEAN
+#include <windows.h>
+#else
+#include <time.h>
+#include <stdlib.h>
+#endif
+
+/*
+ * Returns the current absolute time in microsecods
+ * TODO: Specify since when the time is calculated
+ */
+uint64_t get_absolute_time_us(void)
+{
+    #ifdef _WIN32
+    FILETIME filetime;
+    GetSystemTimePreciseAsFileTime(&filetime);
+    uint64_t time = (uint64_t) filetime.dwLowDateTime | ((uint64_t) filetime.dwHighDateTime << 32);
+    time /= 10;
+    return time;
+    #else
+    struct timespec buffer;
+    if (clock_gettime(CLOCK_REALTIME, &buffer))
+        abort();
+    uint64_t time = buffer.tv_sec * 1000000 + buffer.tv_nsec / 1000;
+    return time;
+    #endif
+}
+
+/*
+ * Returns the current time in nanoseconds since
+ * an unspecified point in time.
+ */
+uint64_t get_relative_time_ns(void)
+{
+    #ifdef _WIN32
+    {
+        int64_t count;
+        int64_t freq;
+        int ok;
+        
+        ok = QueryPerformanceCounter((LARGE_INTEGER*) &count);
+        if (!ok) abort();
+
+        ok = QueryPerformanceFrequency((LARGE_INTEGER*) &freq);
+        if (!ok) abort();
+
+        uint64_t res = 1000000000 * (double) count / freq;
+        return res;
+    }
+    #else
+    {
+        struct timespec time;
+
+        if (clock_gettime(CLOCK_REALTIME, &time))
+            abort();
+
+        uint64_t res;
+
+        uint64_t sec = time.tv_sec;
+        if (sec > UINT64_MAX / 1000000000)
+            abort();
+        res = sec * 1000000000;
+        
+        uint64_t nsec = time.tv_nsec;
+        if (res > UINT64_MAX - nsec)
+            abort();
+        res += nsec;
+
+        return res;
+    }
+    #endif
+}