1 files changed, 54 insertions, 0 deletions
diff --git a/sync.c b/sync.c
new file mode 100644
index 0000000..1b6b6bc
--- /dev/null
+++ b/sync.c
@@ -0,0 +1,54 @@
+#include "project.h"
+
+#define SLEEP_MIN 100000
+#define THRESH 1000
+
+void sync_to_second (struct timeval *ret)
+{
+  struct timeval tv1, tv2;
+  ret->tv_usec = 0;
+
+  for (;;) {
+    tv2.tv_sec = 0;
+    gettimeofday (&tv1, NULL);
+    tv2.tv_usec = 1000000 - tv1.tv_usec;
+
+    if (tv1.tv_usec < THRESH) {
+      ret->tv_sec = tv1.tv_sec;
+      return;
+    } else if (tv2.tv_usec < THRESH) {
+      ret->tv_sec = tv1.tv_sec + 1;
+      return;
+    }
+
+    if (tv2.tv_usec > SLEEP_MIN)
+      select (0, NULL, NULL, NULL, &tv2);
+    else
+      usleep (tv2.tv_usec / 2);
+  }
+}
+
+
+
+void sync_to_minute (struct timeval *ret)
+{
+  struct timeval tv1, tv2;
+  ret->tv_usec = 0;
+
+  for (;;) {
+    tv2.tv_sec = 0;
+    gettimeofday (&tv1, NULL);
+    tv2.tv_sec = 60 - (tv1.tv_sec % 60);
+    tv2.tv_usec = 1000;
+
+    printf ("%d seconds left in min\n", (int) tv2.tv_sec);
+
+    if (tv2.tv_sec > 1) {
+      tv2.tv_sec /= 2;
+      select (0, NULL, NULL, NULL, &tv2);
+    } else {
+      sync_to_second (ret);
+      return;
+    }
+  }
+}