codekingpro/portable-devtools

1// Copyright 2010 The Go Authors. All rights reserved.2// Use of this source code is governed by a BSD-style3// license that can be found in the LICENSE file.4 5package math6 7// Dim returns the maximum of x-y or 0.8//9// Special cases are:10//11//	Dim(+Inf, +Inf) = NaN12//	Dim(-Inf, -Inf) = NaN13//	Dim(x, NaN) = Dim(NaN, x) = NaN14func Dim(x, y float64) float64 {15	// The special cases result in NaN after the subtraction:16	//      +Inf - +Inf = NaN17	//      -Inf - -Inf = NaN18	//       NaN - y    = NaN19	//         x - NaN  = NaN20	v := x - y21	if v <= 0 {22		// v is negative or 023		return 024	}25	// v is positive or NaN26	return v27}28 29// Max returns the larger of x or y.30//31// Special cases are:32//33//	Max(x, +Inf) = Max(+Inf, x) = +Inf34//	Max(x, NaN) = Max(NaN, x) = NaN35//	Max(+0, ±0) = Max(±0, +0) = +036//	Max(-0, -0) = -037//38// Note that this differs from the built-in function max when called39// with NaN and +Inf.40func Max(x, y float64) float64 {41	if haveArchMax {42		return archMax(x, y)43	}44	return max(x, y)45}46 47func max(x, y float64) float64 {48	// special cases49	switch {50	case IsInf(x, 1) || IsInf(y, 1):51		return Inf(1)52	case IsNaN(x) || IsNaN(y):53		return NaN()54	case x == 0 && x == y:55		if Signbit(x) {56			return y57		}58		return x59	}60	if x > y {61		return x62	}63	return y64}65 66// Min returns the smaller of x or y.67//68// Special cases are:69//70//	Min(x, -Inf) = Min(-Inf, x) = -Inf71//	Min(x, NaN) = Min(NaN, x) = NaN72//	Min(-0, ±0) = Min(±0, -0) = -073//74// Note that this differs from the built-in function min when called75// with NaN and -Inf.76func Min(x, y float64) float64 {77	if haveArchMin {78		return archMin(x, y)79	}80	return min(x, y)81}82 83func min(x, y float64) float64 {84	// special cases85	switch {86	case IsInf(x, -1) || IsInf(y, -1):87		return Inf(-1)88	case IsNaN(x) || IsNaN(y):89		return NaN()90	case x == 0 && x == y:91		if Signbit(x) {92			return x93		}94		return y95	}96	if x < y {97		return x98	}99	return y100}101