undo actually not quite done yet

1 files changed, 65 insertions, 0 deletions

diff --git a/time.c b/time.c
new file mode 100644
index 0000000..fb007ba
--- /dev/null
+++ b/time.c
@@ -0,0 +1,65 @@
+#include <time.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+static struct timespec time_last_modified(char const *filename) {
+#if __unix__
+	struct stat statbuf = {};
+	stat(filename, &statbuf);
+	return statbuf.st_mtim;
+#else
+	// windows' _stat does not have st_mtim
+	struct _stat statbuf = {};
+	struct timespec ts = {};
+	_stat(filename, &statbuf);
+	ts.tv_sec = statbuf.st_mtime;
+	return ts;
+#endif
+}
+
+static int timespec_cmp(struct timespec a, struct timespec b) {
+	if (a.tv_sec  > b.tv_sec)  return 1;
+	if (a.tv_sec  < b.tv_sec)  return -1;
+	if (a.tv_nsec > b.tv_nsec) return 1;
+	if (a.tv_nsec < b.tv_nsec) return -1;
+	return 0;
+}
+
+static bool timespec_eq(struct timespec a, struct timespec b) {
+	return timespec_cmp(a, b) == 0;
+}
+
+static struct timespec timespec_max(struct timespec a, struct timespec b) {
+	return timespec_cmp(a, b) < 0 ? b : a;
+}
+
+// sleep for a certain number of nanoseconds
+static void sleep_ns(u64 ns) {
+#if __unix__
+	struct timespec rem = {}, req = {
+		(time_t)(ns / 1000000000),
+		(long)(ns % 1000000000)
+	};
+	
+	while (nanosleep(&req, &rem) == EINTR) // sleep interrupted by signal
+		req = rem;
+#else
+	// windows....
+	Sleep((DWORD)(ns / 1000000));
+#endif
+}
+
+// sleep for microseconds
+static void time_sleep_us(u64 us) {
+	sleep_ns(us * 1000);
+}
+
+// sleep for milliseconds
+static void time_sleep_ms(u64 ms) {
+	sleep_ns(ms * 1000000);
+}
+
+// sleep for seconds
+static void time_sleep_s(u64 s) {
+	sleep_ns(s * 1000000000);
+}