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Diffstat (limited to 'vendor/k8s.io/apimachinery/pkg/api/resource/amount.go')
-rw-r--r-- | vendor/k8s.io/apimachinery/pkg/api/resource/amount.go | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/vendor/k8s.io/apimachinery/pkg/api/resource/amount.go b/vendor/k8s.io/apimachinery/pkg/api/resource/amount.go new file mode 100644 index 000000000..a8866a43e --- /dev/null +++ b/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 +} |