vendor files

vendor/k8s.io/apimachinery/pkg/api/resource/amount.go

@@ -0,0 +1,299 @@
+/*
+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 (
+	"math/big"
+	"strconv"
+
+	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
+}
+
+// Sign returns 0 if the value is zero, -1 if it is less than 0, or 1 if it is greater than 0.
+func (a int64Amount) Sign() int {
+	switch {
+	case a.value == 0:
+		return 0
+	case a.value > 0:
+		return 1
+	default:
+		return -1
+	}
+}
+
+// AsInt64 returns the current amount as an int64 at scale 0, or false if the value cannot be
+// represented in an int64 OR would result in a loss of precision. This method is intended as
+// an optimization to avoid calling AsDec.
+func (a int64Amount) AsInt64() (int64, bool) {
+	if a.scale == 0 {
+		return a.value, true
+	}
+	if a.scale < 0 {
+		// TODO: attempt to reduce factors, although it is assumed that factors are reduced prior
+		// to the int64Amount being created.
+		return 0, false
+	}
+	return positiveScaleInt64(a.value, a.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
+	}
+}
+
+// Add adds two int64Amounts together, matching scales. It will return false and not mutate
+// a if overflow or underflow would result.
+func (a *int64Amount) Add(b int64Amount) bool {
+	switch {
+	case b.value == 0:
+		return true
+	case a.value == 0:
+		a.value = b.value
+		a.scale = b.scale
+		return true
+	case a.scale == b.scale:
+		c, ok := int64Add(a.value, b.value)
+		if !ok {
+			return false
+		}
+		a.value = c
+	case a.scale > b.scale:
+		c, ok := positiveScaleInt64(a.value, a.scale-b.scale)
+		if !ok {
+			return false
+		}
+		c, ok = int64Add(c, b.value)
+		if !ok {
+			return false
+		}
+		a.scale = b.scale
+		a.value = c
+	default:
+		c, ok := positiveScaleInt64(b.value, b.scale-a.scale)
+		if !ok {
+			return false
+		}
+		c, ok = int64Add(a.value, c)
+		if !ok {
+			return false
+		}
+		a.value = c
+	}
+	return true
+}
+
+// Sub removes the value of b from the current amount, or returns false if underflow would result.
+func (a *int64Amount) Sub(b int64Amount) bool {
+	return a.Add(int64Amount{value: -b.value, scale: b.scale})
+}
+
+// AsScale adjusts this amount to set a minimum scale, rounding up, and returns true iff no precision
+// was lost. (1.1e5).AsScale(5) would return 1.1e5, but (1.1e5).AsScale(6) would return 1e6.
+func (a int64Amount) AsScale(scale Scale) (int64Amount, bool) {
+	if a.scale >= scale {
+		return a, true
+	}
+	result, exact := negativeScaleInt64(a.value, scale-a.scale)
+	return int64Amount{value: result, scale: scale}, exact
+}
+
+// AsCanonicalBytes accepts a buffer to write the base-10 string value of this field to, and returns
+// either that buffer or a larger buffer and the current exponent of the value. The value is adjusted
+// until the exponent is a multiple of 3 - i.e. 1.1e5 would return "110", 3.
+func (a int64Amount) AsCanonicalBytes(out []byte) (result []byte, exponent int32) {
+	mantissa := a.value
+	exponent = int32(a.scale)
+
+	amount, times := removeInt64Factors(mantissa, 10)
+	exponent += int32(times)
+
+	// make sure exponent is a multiple of 3
+	var ok bool
+	switch exponent % 3 {
+	case 1, -2:
+		amount, ok = int64MultiplyScale10(amount)
+		if !ok {
+			return infDecAmount{a.AsDec()}.AsCanonicalBytes(out)
+		}
+		exponent = exponent - 1
+	case 2, -1:
+		amount, ok = int64MultiplyScale100(amount)
+		if !ok {
+			return infDecAmount{a.AsDec()}.AsCanonicalBytes(out)
+		}
+		exponent = exponent - 2
+	}
+	return strconv.AppendInt(out, amount, 10), exponent
+}
+
+// AsCanonicalBase1024Bytes accepts a buffer to write the base-1024 string value of this field to, and returns
+// either that buffer or a larger buffer and the current exponent of the value. 2048 is 2 * 1024 ^ 1 and would
+// return []byte("2048"), 1.
+func (a int64Amount) AsCanonicalBase1024Bytes(out []byte) (result []byte, exponent int32) {
+	value, ok := a.AsScaledInt64(0)
+	if !ok {
+		return infDecAmount{a.AsDec()}.AsCanonicalBase1024Bytes(out)
+	}
+	amount, exponent := removeInt64Factors(value, 1024)
+	return strconv.AppendInt(out, amount, 10), exponent
+}
+
+// infDecAmount implements common operations over an inf.Dec that are specific to the quantity
+// representation.
+type infDecAmount struct {
+	*inf.Dec
+}
+
+// AsScale adjusts this amount to set a minimum scale, rounding up, and returns true iff no precision
+// was lost. (1.1e5).AsScale(5) would return 1.1e5, but (1.1e5).AsScale(6) would return 1e6.
+func (a infDecAmount) AsScale(scale Scale) (infDecAmount, bool) {
+	tmp := &inf.Dec{}
+	tmp.Round(a.Dec, scale.infScale(), inf.RoundUp)
+	return infDecAmount{tmp}, tmp.Cmp(a.Dec) == 0
+}
+
+// AsCanonicalBytes accepts a buffer to write the base-10 string value of this field to, and returns
+// either that buffer or a larger buffer and the current exponent of the value. The value is adjusted
+// until the exponent is a multiple of 3 - i.e. 1.1e5 would return "110", 3.
+func (a infDecAmount) AsCanonicalBytes(out []byte) (result []byte, exponent int32) {
+	mantissa := a.Dec.UnscaledBig()
+	exponent = int32(-a.Dec.Scale())
+	amount := big.NewInt(0).Set(mantissa)
+	// move all factors of 10 into the exponent for easy reasoning
+	amount, times := removeBigIntFactors(amount, bigTen)
+	exponent += times
+
+	// make sure exponent is a multiple of 3
+	for exponent%3 != 0 {
+		amount.Mul(amount, bigTen)
+		exponent--
+	}
+
+	return append(out, amount.String()...), exponent
+}
+
+// AsCanonicalBase1024Bytes accepts a buffer to write the base-1024 string value of this field to, and returns
+// either that buffer or a larger buffer and the current exponent of the value. 2048 is 2 * 1024 ^ 1 and would
+// return []byte("2048"), 1.
+func (a infDecAmount) AsCanonicalBase1024Bytes(out []byte) (result []byte, exponent int32) {
+	tmp := &inf.Dec{}
+	tmp.Round(a.Dec, 0, inf.RoundUp)
+	amount, exponent := removeBigIntFactors(tmp.UnscaledBig(), big1024)
+	return append(out, amount.String()...), exponent
+}