new /x/jsonx and /x/mathx util sub-packages

x/mathx/round.go

@@ -0,0 +1,28 @@
+package mathx
+
+import "math"
+
+// Round rounds the "input" on "roundOn" (e.g. 0.5) on "places" digits.
+func Round(input float64, roundOn float64, places float64) float64 {
+	pow := math.Pow(10, places)
+	digit := pow * input
+
+	_, div := math.Modf(digit)
+	if div >= roundOn {
+		return math.Ceil(digit) / pow
+	}
+
+	return math.Floor(digit) / pow
+}
+
+// RoundUp rounds up the "input" up to "places" digits.
+func RoundUp(input float64, places float64) float64 {
+	pow := math.Pow(10, places)
+	return math.Ceil(pow*input) / pow
+}
+
+// RoundDown rounds down the "input" up to "places" digits.
+func RoundDown(input float64, places float64) float64 {
+	pow := math.Pow(10, places)
+	return math.Floor(pow*input) / pow
+}