30 lines
783 B
Go
30 lines
783 B
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package math
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// Nextafter returns the next representable value after x towards y.
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// If x == y, then x is returned.
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//
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// Special cases are:
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// Nextafter(NaN, y) = NaN
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// Nextafter(x, NaN) = NaN
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func Nextafter(x, y float64) (r float64) {
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// TODO(rsc): Remove manual inlining of IsNaN
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// when compiler does it for us
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switch {
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case x != x || y != y: // IsNaN(x) || IsNaN(y): // special case
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r = NaN()
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case x == y:
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r = x
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case x == 0:
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r = Copysign(Float64frombits(1), y)
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case (y > x) == (x > 0):
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r = Float64frombits(Float64bits(x) + 1)
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default:
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r = Float64frombits(Float64bits(x) - 1)
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}
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return
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}
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