Add timer library.

1 files changed, 55 insertions, 0 deletions

diff --git a/timer/include/timer.h b/timer/include/timer.h
new file mode 100644
index 0000000..0274c69
--- /dev/null
+++ b/timer/include/timer.h
@@ -0,0 +1,55 @@
+#pragma once
+
+#include <stdint.h>
+
+/// A particular point in time.
+#ifdef _WIN32
+typedef uint64_t time_point;
+#else
+#include <time.h>
+typedef struct timespec time_point;
+#endif
+
+/// Time elapsed between two time points.
+typedef uint64_t time_delta;
+
+/// A high resolution timer.
+typedef struct {
+  time_point start_time;   // The instant the timer was last started.
+  time_point last_tick;    // The instant the timer was last ticked.
+  time_delta running_time; // Time elapsed since the timer was last started.
+  time_delta delta_time;   // Time elapsed since the last tick.
+} Timer;
+
+/// Construct a new timer.
+Timer timer_make(void);
+
+/// Start the timer.
+/// This sets the time point from which time deltas are measured.
+/// Calling this multilple times resets the timer.
+void timer_start(Timer*);
+
+/// Update the timer's running and delta times.
+void timer_tick(Timer*);
+
+/// Get the current time.
+time_point time_now(void);
+
+/// Return the time elapsed between two timestamps.
+time_delta time_diff(time_point start, time_point end);
+
+/// Return the time elapsed in seconds.
+double time_delta_to_sec(time_delta dt);
+
+/// Convert the time elapsed in seconds to a time delta.
+time_delta sec_to_time_delta(double seconds);
+
+/// Put the caller thread to sleep for the given amount of time.
+void time_sleep(time_delta dt);
+
+/// The time point 0.
+#ifdef _WIN32
+static const time_point time_zero = 0;
+#else
+static const time_point time_zero = {0, 0};
+#endif