Source file src/pkg/math/nextafter.go

     1	// Copyright 2010 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	package math
     6	
     7	// Nextafter32 returns the next representable float32 value after x towards y.
     8	//
     9	// Special cases are:
    10	//	Nextafter32(x, x)   = x
    11	//	Nextafter32(NaN, y) = NaN
    12	//	Nextafter32(x, NaN) = NaN
    13	func Nextafter32(x, y float32) (r float32) {
    14		switch {
    15		case IsNaN(float64(x)) || IsNaN(float64(y)): // special case
    16			r = float32(NaN())
    17		case x == y:
    18			r = x
    19		case x == 0:
    20			r = float32(Copysign(float64(Float32frombits(1)), float64(y)))
    21		case (y > x) == (x > 0):
    22			r = Float32frombits(Float32bits(x) + 1)
    23		default:
    24			r = Float32frombits(Float32bits(x) - 1)
    25		}
    26		return
    27	}
    28	
    29	// Nextafter returns the next representable float64 value after x towards y.
    30	//
    31	// Special cases are:
    32	//	Nextafter(x, x)   = x
    33	//	Nextafter(NaN, y) = NaN
    34	//	Nextafter(x, NaN) = NaN
    35	func Nextafter(x, y float64) (r float64) {
    36		switch {
    37		case IsNaN(x) || IsNaN(y): // special case
    38			r = NaN()
    39		case x == y:
    40			r = x
    41		case x == 0:
    42			r = Copysign(Float64frombits(1), y)
    43		case (y > x) == (x > 0):
    44			r = Float64frombits(Float64bits(x) + 1)
    45		default:
    46			r = Float64frombits(Float64bits(x) - 1)
    47		}
    48		return
    49	}
    50	

View as plain text