1 files changed, 18 insertions, 0 deletions

diff --git a/lib/round.h b/lib/round.h
new file mode 100644
index 0000000..3aa6642
--- /dev/null
+++ b/lib/round.h
@@ -0,0 +1,18 @@
+#ifndef __LIB_ROUND_H
+#define __LIB_ROUND_H
+
+/* Yields X rounded up to the nearest multiple of STEP.
+   For X >= 0, STEP >= 1 only. */
+#define ROUND_UP(X, STEP) (((X) + (STEP) - 1) / (STEP) * (STEP))
+
+/* Yields X divided by STEP, rounded up.
+   For X >= 0, STEP >= 1 only. */
+#define DIV_ROUND_UP(X, STEP) (((X) + (STEP) - 1) / (STEP))
+
+/* Yields X rounded down to the nearest multiple of STEP.
+   For X >= 0, STEP >= 1 only. */
+#define ROUND_DOWN(X, STEP) ((X) / (STEP) * (STEP))
+
+/* There is no DIV_ROUND_DOWN.   It would be simply X / STEP. */
+
+#endif /* lib/round.h */