mirror of
https://github.com/mum4k/termdash.git
synced 2025-04-28 13:48:51 +08:00
108 lines
2.6 KiB
Go
108 lines
2.6 KiB
Go
// Copyright 2019 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package numbers implements various numerical functions.
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package numbers
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import (
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"math"
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)
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// RoundToNonZeroPlaces rounds the float up, so that it has at least the provided
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// number of non-zero decimal places.
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// Returns the rounded float and the number of leading decimal places that
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// are zero. Returns the original float when places is zero. Negative places
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// are treated as positive, so that -2 == 2.
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func RoundToNonZeroPlaces(f float64, places int) (float64, int) {
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if f == 0 {
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return 0, 0
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}
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decOnly := zeroBeforeDecimal(f)
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if decOnly == 0 {
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return f, 0
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}
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nzMult := multToNonZero(decOnly)
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if places == 0 {
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return f, multToPlaces(nzMult)
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}
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plMult := placesToMult(places)
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m := float64(nzMult * plMult)
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return math.Ceil(f*m) / m, multToPlaces(nzMult)
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}
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// multToNonZero returns multiplier for the float, so that the first decimal
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// place is non-zero. The float must not be zero.
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func multToNonZero(f float64) int {
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v := f
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if v < 0 {
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v *= -1
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}
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mult := 1
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for v < 0.1 {
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v *= 10
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mult *= 10
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}
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return mult
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}
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// placesToMult translates the number of decimal places to a multiple of 10.
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func placesToMult(places int) int {
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if places < 0 {
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places *= -1
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}
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mult := 1
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for i := 0; i < places; i++ {
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mult *= 10
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}
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return mult
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}
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// multToPlaces translates the multiple of 10 to a number of decimal places.
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func multToPlaces(mult int) int {
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places := 0
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for mult > 1 {
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mult /= 10
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places++
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}
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return places
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}
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// zeroBeforeDecimal modifies the float so that it only has zero value before
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// the decimal point.
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func zeroBeforeDecimal(f float64) float64 {
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var sign float64 = 1
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if f < 0 {
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f *= -1
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sign = -1
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}
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floor := math.Floor(f)
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return (f - floor) * sign
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}
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// Round returns the nearest integer, rounding half away from zero.
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// Copied from the math package of Go 1.10 for backwards compatibility with Go
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// 1.8 where the math.Round function doesn't exist yet.
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func Round(x float64) float64 {
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t := math.Trunc(x)
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if math.Abs(x-t) >= 0.5 {
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return t + math.Copysign(1, x)
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}
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return t
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}
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