Added the hires timer to utils

src/utils/timer_hires.h

@@ -0,0 +1,63 @@
+/*
+    Copyright (C) 2014-2019, Johannes Pekkilae, Miikka Vaeisalae.
+
+    This file is part of Astaroth.
+
+    Astaroth is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Astaroth is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Astaroth.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+  @file
+ \brief High-resolution timer.
+
+    Usage:
+        Timer t;
+        timer_reset(&t);
+        timer_diff_nsec(t);
+
+    If there are issues, try compiling with -std=gnu11 -lrt
+ */
+#pragma once
+#include <stdio.h> // perror
+#include <time.h>
+
+typedef struct timespec Timer;
+// Contains at least the following members:
+// time_t tv_sec;
+// long tv_nsec;
+
+static inline int
+timer_reset(Timer* t)
+{
+    const int retval = clock_gettime(CLOCK_REALTIME, t);
+    if (retval == -1)
+        perror("clock_gettime failure");
+
+    return retval;
+}
+
+static inline long
+timer_diff_nsec(const Timer start)
+{
+    Timer end;
+    timer_reset(&end);
+    const long diff = (end.tv_sec - start.tv_sec) * 1000000000l + (end.tv_nsec - start.tv_nsec);
+    return diff;
+}
+
+static inline void
+timer_diff_print(const Timer t)
+{
+    printf("Time elapsed: %g ms\n", timer_diff_nsec(t) / 1e6);
+}