53 lines
1.2 KiB
Go
53 lines
1.2 KiB
Go
// Copyright 2009-2010 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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// Floor returns the greatest integer value less than or equal to x.
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//
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// Special cases are:
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// Floor(+Inf) = +Inf
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// Floor(-Inf) = -Inf
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// Floor(NaN) = NaN
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func Floor(x float64) float64 {
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// TODO(rsc): Remove manual inlining of IsNaN, IsInf
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// when compiler does it for us
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if x == 0 || x != x || x > MaxFloat64 || x < -MaxFloat64 { // x == 0 || IsNaN(x) || IsInf(x, 0)
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return x
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}
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if x < 0 {
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d, fract := Modf(-x)
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if fract != 0.0 {
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d = d + 1
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}
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return -d
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}
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d, _ := Modf(x)
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return d
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}
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// Ceil returns the least integer value greater than or equal to x.
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//
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// Special cases are:
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// Ceil(+Inf) = +Inf
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// Ceil(-Inf) = -Inf
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// Ceil(NaN) = NaN
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func Ceil(x float64) float64 { return -Floor(-x) }
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// Trunc returns the integer value of x.
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//
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// Special cases are:
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// Trunc(+Inf) = +Inf
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// Trunc(-Inf) = -Inf
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// Trunc(NaN) = NaN
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func Trunc(x float64) float64 {
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// TODO(rsc): Remove manual inlining of IsNaN, IsInf
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// when compiler does it for us
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if x == 0 || x != x || x > MaxFloat64 || x < -MaxFloat64 { // x == 0 || IsNaN(x) || IsInf(x, 0)
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return x
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}
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d, _ := Modf(x)
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return d
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}
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