| // Copyright 2010 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package math |
| |
| // Nextafter32 returns the next representable float32 value after x towards y. |
| // Special cases: |
| // Nextafter32(x, x) = x |
| // Nextafter32(NaN, y) = NaN |
| // Nextafter32(x, NaN) = NaN |
| func Nextafter32(x, y float32) (r float32) { |
| switch { |
| case IsNaN(float64(x)) || IsNaN(float64(y)): // special case |
| r = float32(NaN()) |
| case x == y: |
| r = x |
| case x == 0: |
| r = float32(Copysign(float64(Float32frombits(1)), float64(y))) |
| case (y > x) == (x > 0): |
| r = Float32frombits(Float32bits(x) + 1) |
| default: |
| r = Float32frombits(Float32bits(x) - 1) |
| } |
| return |
| } |
| |
| // Nextafter returns the next representable float64 value after x towards y. |
| // Special cases: |
| // Nextafter64(x, x) = x |
| // Nextafter64(NaN, y) = NaN |
| // Nextafter64(x, NaN) = NaN |
| func Nextafter(x, y float64) (r float64) { |
| switch { |
| case IsNaN(x) || IsNaN(y): // special case |
| r = NaN() |
| case x == y: |
| r = x |
| case x == 0: |
| r = Copysign(Float64frombits(1), y) |
| case (y > x) == (x > 0): |
| r = Float64frombits(Float64bits(x) + 1) |
| default: |
| r = Float64frombits(Float64bits(x) - 1) |
| } |
| return |
| } |