misc.c: add a few basic clock functions

src/misc.c

@@ -0,0 +1,112 @@
+/* misc.c - generic/catchall functions.
+ *
+ * Copyright (C) 2024 Bruno Raoult ("br")
+ * Licensed under the GNU General Public License v3.0 or later.
+ * Some rights reserved. See COPYING.
+ *
+ * You should have received a copy of the GNU General Public License along with this
+ * program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
+ *
+ */
+
+#include <time.h>
+
+#include "chessdefs.h"
+
+/*
+ * 1 sec      = 1000 millisec
+ * 1 millisec = 1000 microsec
+ * 1 microsec = 1000 nanosec
+ * milli = sec * 1000 + nanosec / 1000000
+ *
+ */
+
+/* We use microsec for all intermediate calcluation */
+#define NANO_IN_MICRO  1000ll                     /* nanosecond in millisecond */
+#define MICRO_IN_SEC   1000000ll                  /* millisecond in second */
+
+#define MILLI_IN_SEC   1000ll                     /* millisecond in second */
+
+#define MICRO_IN_MILLI 1000ll
+
+//#define NANO_IN_MILLI  1000000ll                         /* nanosecond in millisecond */
+//#define NANO_IN_SEC    (NANOS_IN_MS * MS_IN_SEC)
+
+
+/**
+ * clock_start - start or restart a clock.
+ * @clock: &mclock_t clock
+ *
+ * Save current time according to @clock type.
+ */
+void clock_start(mclock_t *clock)
+{
+    clock_gettime(clock->clocktype, &clock->start);
+}
+
+/**
+ * clock_init - initializes a clock type.
+ * @clock: &mclock_t clock
+ * @type: clock type
+ *
+ * See the clock_gettime(2) for details.
+ * CLOCK_WALL (a.k.a CLOCK_REALTIME): Wall clock.
+ * CLOCK_SYSTEM (a.k.a CLOCK_MONOTONIC_RAW): System clock.
+ * CLOCK_PROCESS (a.k.a CLOCK_PROCESS_CPUTIME_ID): Process CPU clock (incl. threads).
+ * CLOCK_THREAD  (a.k.a CLOCK_THREAD_CPUTIME_ID): Thread CPU clock.
+ */
+void clock_init(mclock_t *clock, clockid_t type)
+{
+    clock->clocktype = type;
+    clock_start(clock);
+}
+
+/**
+ * clock_elapsed_μs - return a mclock_t elapsed time in microseconds.
+ * @clock: &mclock_t clock
+ *
+ * The elapsed time is calculated between current time and last clock_start(@clock)
+ * call time.
+ *
+ * @return: microseconds elapsed since last clock_start().
+ */
+s64 clock_elapsed_μs(mclock_t *clock)
+{
+    struct timespec current;
+    s64 μs;
+
+    clock_gettime(clock->clocktype, &current);
+    μs = ((s64)current.tv_sec - (s64)clock->start.tv_sec) * MICRO_IN_SEC +
+        ((s64)current.tv_nsec - (s64)clock->start.tv_nsec) / NANO_IN_MICRO ;
+    return μs;
+}
+
+/**
+ * clock_elapsed_ms - return a mclock_t elapsed time in milliseconds.
+ * @clock: &mclock_t clock
+ *
+ * The elapsed time is calculated between current time and last clock_start(@clock)
+ * call time.
+ *
+ * @return: milliseconds elapsed since last clock_start().
+ */
+s64 clock_elapsed_ms(mclock_t *clock)
+{
+    return clock_elapsed_μs(clock) / MICRO_IN_MILLI;
+}
+
+/**
+ * clock_elapsed_sec - return a mclock_t elapsed time in seconds.
+ * @clock: &mclock_t clock
+ *
+ * The elapsed time is calculated between current time and last clock_start(@clock)
+ * call time.
+ *
+ * @return: seconds elapsed since last clock_start().
+ */
+double clock_elapsed_sec(mclock_t *clock)
+{
+    return (double) clock_elapsed_μs(clock) / (double) MICRO_IN_SEC;
+}