add ratio ceil and floor operators on amount_msat

Changelog-none: add ratio ceil and floor operators on amount_msat

Signed-off-by: Lagrang3 <[email protected]>

Author: Lagrang3

common/amount.c

@@ -516,6 +516,16 @@ double amount_msat_ratio(struct amount_msat a, struct amount_msat b)
 	return (double)a.millisatoshis / b.millisatoshis;
 }
 
+u64 amount_msat_ratio_floor(struct amount_msat a, struct amount_msat b)
+{
+	return a.millisatoshis / b.millisatoshis;
+}
+
+u64 amount_msat_ratio_ceil(struct amount_msat a, struct amount_msat b)
+{
+	return (a.millisatoshis + b.millisatoshis - 1) / b.millisatoshis;
+}
+
 struct amount_msat amount_msat_div(struct amount_msat msat, u64 div)
 {
 	msat.millisatoshis /= div;

common/amount.h

@@ -148,6 +148,12 @@ bool amount_msat_eq_sat(struct amount_msat msat, struct amount_sat sat);
 /* a / b */
 double amount_msat_ratio(struct amount_msat a, struct amount_msat b);
 
+/* floor(a/b) */
+u64 amount_msat_ratio_floor(struct amount_msat a, struct amount_msat b);
+
+/* ceil(a/b) */
+u64 amount_msat_ratio_ceil(struct amount_msat a, struct amount_msat b);
+
 /* min(a,b) and max(a,b) */
 static inline struct amount_msat amount_msat_min(struct amount_msat a,
 						 struct amount_msat b)