update cadvisor to v0.31.0

vendor/github.com/mesos/mesos-go/api/v1/lib/fixedpoint.go

@@ -0,0 +1,35 @@
+package mesos
+
+// fixed point scalar math from mesos:src/common/values.cpp
+// --
+// We manipulate scalar values by converting them from floating point to a
+// fixed point representation, doing a calculation, and then converting
+// the result back to floating point. We deliberately only preserve three
+// decimal digits of precision in the fixed point representation. This
+// ensures that client applications see predictable numerical behavior, at
+// the expense of sacrificing some precision.
+
+import "math"
+
+func convertToFloat64(f int64) float64 {
+	// NOTE: We do the conversion from fixed point via integer division
+	// and then modulus, rather than a single floating point division.
+	// This ensures that we only apply floating point division to inputs
+	// in the range [0,999], which is easier to check for correctness.
+	var (
+		quotient  = float64(f / 1000)
+		remainder = float64(f%1000) / 1000.0
+	)
+	return quotient + remainder
+}
+
+func convertToFixed64(f float64) int64 {
+	return round64(f * 1000)
+}
+
+func round64(f float64) int64 {
+	if math.Abs(f) < 0.5 {
+		return 0
+	}
+	return int64(f + math.Copysign(0.5, f))
+}