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