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/*
Copyright 2014 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package resource
import (
inf "gopkg.in/inf.v0"
)
// Scale is used for getting and setting the base-10 scaled value.
// Base-2 scales are omitted for mathematical simplicity.
// See Quantity.ScaledValue for more details.
type Scale int32
// infScale adapts a Scale value to an inf.Scale value.
func (s Scale) infScale() inf.Scale {
return inf.Scale(-s) // inf.Scale is upside-down
}
const (
Nano Scale = -9
Micro Scale = -6
Milli Scale = -3
Kilo Scale = 3
Mega Scale = 6
Giga Scale = 9
Tera Scale = 12
Peta Scale = 15
Exa Scale = 18
)
var (
Zero = int64Amount{}
// Used by quantity strings - treat as read only
zeroBytes = []byte("0")
)
// int64Amount represents a fixed precision numerator and arbitrary scale exponent. It is faster
// than operations on inf.Dec for values that can be represented as int64.
// +k8s:openapi-gen=true
type int64Amount struct {
value int64
scale Scale
}
// AsScaledInt64 returns an int64 representing the value of this amount at the specified scale,
// rounding up, or false if that would result in overflow. (1e20).AsScaledInt64(1) would result
// in overflow because 1e19 is not representable as an int64. Note that setting a scale larger
// than the current value may result in loss of precision - i.e. (1e-6).AsScaledInt64(0) would
// return 1, because 0.000001 is rounded up to 1.
func (a int64Amount) AsScaledInt64(scale Scale) (result int64, ok bool) {
if a.scale < scale {
result, _ = negativeScaleInt64(a.value, scale-a.scale)
return result, true
}
return positiveScaleInt64(a.value, a.scale-scale)
}
// AsDec returns an inf.Dec representation of this value.
func (a int64Amount) AsDec() *inf.Dec {
var base inf.Dec
base.SetUnscaled(a.value)
base.SetScale(inf.Scale(-a.scale))
return &base
}
// Cmp returns 0 if a and b are equal, 1 if a is greater than b, or -1 if a is less than b.
func (a int64Amount) Cmp(b int64Amount) int {
switch {
case a.scale == b.scale:
// compare only the unscaled portion
case a.scale > b.scale:
result, remainder, exact := divideByScaleInt64(b.value, a.scale-b.scale)
if !exact {
return a.AsDec().Cmp(b.AsDec())
}
if result == a.value {
switch {
case remainder == 0:
return 0
case remainder > 0:
return -1
default:
return 1
}
}
b.value = result
default:
result, remainder, exact := divideByScaleInt64(a.value, b.scale-a.scale)
if !exact {
return a.AsDec().Cmp(b.AsDec())
}
if result == b.value {
switch {
case remainder == 0:
return 0
case remainder > 0:
return 1
default:
return -1
}
}
a.value = result
}
switch {
case a.value == b.value:
return 0
case a.value < b.value:
return -1
default:
return 1
}
}
// infDecAmount implements common operations over an inf.Dec that are specific to the quantity
// representation.
type infDecAmount struct {
*inf.Dec
}
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