1 // Copyright 2014 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // +build !go1.4 6 7 package constant 8 9 import ( 10 "math" 11 "math/big" 12 ) 13 14 func ratToFloat32(x *big.Rat) (float32, bool) { 15 // Before 1.4, there's no Rat.Float32. 16 // Emulate it, albeit at the cost of 17 // imprecision in corner cases. 18 x64, exact := x.Float64() 19 x32 := float32(x64) 20 if math.IsInf(float64(x32), 0) { 21 exact = false 22 } 23 return x32, exact 24 } 25
