resource

package
v0.8.11 Latest Latest
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 Go to latest Published: Sep 19, 2017 License: Apache-2.0 Imports: 11 Imported by: 2

README

This package was copied in from the Kubernetes repo to avoid a cyclic dependency. These files were taken from master from github.com/kubernetes/kubernetes at commit hash b0deb2eb8f4037421077f77cb163dbb4c0a2a9f5.

Documentation

Index

Examples

Constants

View Source 
const (
	DecimalExponent = Format("DecimalExponent") // e.g., 12e6
	BinarySI        = Format("BinarySI")        // e.g., 12Mi (12 * 2^20)
	DecimalSI       = Format("DecimalSI")       // e.g., 12M  (12 * 10^6)
)

Variables

View Source 
var (

	// Errors that could happen while parsing a string.
	ErrFormatWrong = errors.New("quantities must match the regular expression '" + splitREString + "'")
	ErrNumeric     = errors.New("unable to parse numeric part of quantity")
	ErrSuffix      = errors.New("unable to parse quantity's suffix")
)
View Source 
var (

	// The maximum value we can represent milli-units for.
	// Compare with the return value of Quantity.Value() to
	// see if it's safe to use Quantity.MilliValue().
	MaxMilliValue = int64(((1 << 63) - 1) / 1000)
)
View Source 
var (
	Zero = int64Amount{}
)

Functions

func NewQuantityFlagValue 

func NewQuantityFlagValue(q *Quantity) flag.Value

NewQuantityFlagValue returns an object that can be used to back a flag, pointing at the given Quantity variable.

Types

type CanonicalValue 

type CanonicalValue interface {
	// AsCanonicalBytes returns a byte array representing the string representation
	// of the value mantissa and an int32 representing its exponent in base-10. Callers may
	// pass a byte slice to the method to avoid allocations.
	AsCanonicalBytes(out []byte) ([]byte, int32)
	// AsCanonicalBase1024Bytes returns a byte array representing the string representation
	// of the value mantissa and an int32 representing its exponent in base-1024. Callers
	// may pass a byte slice to the method to avoid allocations.
	AsCanonicalBase1024Bytes(out []byte) ([]byte, int32)
}

CanonicalValue allows a quantity amount to be converted to a string.

type Format 

type Format string

Format lists the three possible formattings of a quantity.

Example 
package main

import (
	"fmt"

	"github.com/appc/spec/schema/types/resource"
)

func main() {
	memorySize := resource.NewQuantity(5*1024*1024*1024, resource.BinarySI)
	fmt.Printf("memorySize = %v\n", memorySize)

	diskSize := resource.NewQuantity(5*1000*1000*1000, resource.DecimalSI)
	fmt.Printf("diskSize = %v\n", diskSize)

	cores := resource.NewMilliQuantity(5300, resource.DecimalSI)
	fmt.Printf("cores = %v\n", cores)

}

Output:

memorySize = 5Gi
diskSize = 5G
cores = 5300m

type Quantity 

type Quantity struct {

	// Change Format at will. See the comment for Canonicalize for
	// more details.
	Format
	// contains filtered or unexported fields
}

Quantity is a fixed-point representation of a number. It provides convenient marshaling/unmarshaling in JSON and YAML, in addition to String() and Int64() accessors.

The serialization format is:

<quantity> ::= <signedNumber><suffix> 

(Note that <suffix> may be empty, from the "" case in <decimalSI>.)

<digit> ::= 0 | 1 | ... | 9 <digits> ::= <digit> | <digit><digits> <number> ::= <digits> | <digits>.<digits> | <digits>. | .<digits> <sign> ::= "+" | "-" <signedNumber> ::= <number> | <sign><number> <suffix> ::= <binarySI> | <decimalExponent> | <decimalSI> <binarySI> ::= Ki | Mi | Gi | Ti | Pi | Ei 

(International System of units; See: http://physics.nist.gov/cuu/Units/binary.html)

<decimalSI> ::= m | "" | k | M | G | T | P | E 

(Note that 1024 = 1Ki but 1000 = 1k; I didn't choose the capitalization.)

<decimalExponent> ::= "e" <signedNumber> | "E" <signedNumber>

No matter which of the three exponent forms is used, no quantity may represent a number greater than 2^63-1 in magnitude, nor may it have more than 3 decimal places. Numbers larger or more precise will be capped or rounded up. (E.g.: 0.1m will rounded up to 1m.) This may be extended in the future if we require larger or smaller quantities.

When a Quantity is parsed from a string, it will remember the type of suffix it had, and will use the same type again when it is serialized.

Before serializing, Quantity will be put in "canonical form". This means that Exponent/suffix will be adjusted up or down (with a corresponding increase or decrease in Mantissa) such that: 

a. No precision is lost
b. No fractional digits will be emitted
c. The exponent (or suffix) is as large as possible.

The sign will be omitted unless the number is negative.

Examples: 

1.5 will be serialized as "1500m"
1.5Gi will be serialized as "1536Mi"

NOTE: We reserve the right to amend this canonical format, perhaps to 

allow 1.5 to be canonical.

TODO: Remove above disclaimer after all bikeshedding about format is over, 

or after March 2015.

Note that the quantity will NEVER be internally represented by a floating point number. That is the whole point of this exercise.

Non-canonical values will still parse as long as they are well formed, but will be re-emitted in their canonical form. (So always use canonical form, or don't diff.)

This format is intended to make it difficult to use these numbers without writing some sort of special handling code in the hopes that that will cause implementors to also use a fixed point implementation.

+gencopy=false +protobuf=true +protobuf.embed=string +protobuf.options.marshal=false +protobuf.options.(gogoproto.goproto_stringer)=false

func MustParse 

func MustParse(str string) Quantity

MustParse turns the given string into a quantity or panics; for tests or others cases where you know the string is valid.

Example 
package main

import (
	"fmt"

	"github.com/appc/spec/schema/types/resource"
)

func main() {
	memorySize := resource.MustParse("5Gi")
	fmt.Printf("memorySize = %v (%v)\n", memorySize.Value(), memorySize.Format)

	diskSize := resource.MustParse("5G")
	fmt.Printf("diskSize = %v (%v)\n", diskSize.Value(), diskSize.Format)

	cores := resource.MustParse("5300m")
	fmt.Printf("milliCores = %v (%v)\n", cores.MilliValue(), cores.Format)

	cores2 := resource.MustParse("5.4")
	fmt.Printf("milliCores = %v (%v)\n", cores2.MilliValue(), cores2.Format)

}

Output:

memorySize = 5368709120 (BinarySI)
diskSize = 5000000000 (DecimalSI)
milliCores = 5300 (DecimalSI)
milliCores = 5400 (DecimalSI)

func NewMilliQuantity 

func NewMilliQuantity(value int64, format Format) *Quantity

NewMilliQuantity returns a new Quantity representing the given value * 1/1000 in the given format. Note that BinarySI formatting will round fractional values, and will be changed to DecimalSI for values x where (-1 < x < 1) && (x != 0).

func NewQuantity 

func NewQuantity(value int64, format Format) *Quantity

NewQuantity returns a new Quantity representing the given value in the given format.

func NewScaledQuantity 

func NewScaledQuantity(value int64, scale Scale) *Quantity

NewScaledQuantity returns a new Quantity representing the given value * 10^scale in DecimalSI format.

func ParseQuantity 

func ParseQuantity(str string) (Quantity, error)

ParseQuantity turns str into a Quantity, or returns an error.

func QuantityFlag 

func QuantityFlag(flagName, defaultValue, description string) *Quantity

QuantityFlag is a helper that makes a quantity flag (using standard flag package). Will panic if defaultValue is not a valid quantity.

func (*Quantity) Add 

func (q *Quantity) Add(y Quantity)

Add adds the provide y quantity to the current value. If the current value is zero, the format of the quantity will be updated to the format of y.

func (*Quantity) AsCanonicalBytes 

func (q *Quantity) AsCanonicalBytes(out []byte) (result []byte, exponent int32)

AsCanonicalBytes returns the canonical byte representation of this quantity as a mantissa and base 10 exponent. The out byte slice may be passed to the method to avoid an extra allocation.

func (*Quantity) AsDec 

func (q *Quantity) AsDec() *inf.Dec

AsDec returns the quantity as represented by a scaled inf.Dec.

func (*Quantity) AsInt64 

func (q *Quantity) AsInt64() (int64, bool)

AsInt64 returns a representation of the current value as an int64 if a fast conversion is possible. If false is returned, callers must use the inf.Dec form of this quantity.

func (*Quantity) AsScale 

func (q *Quantity) AsScale(scale Scale) (CanonicalValue, bool)

AsScaled returns the current value, rounded up to the provided scale, and returns false if the scale resulted in a loss of precision.

func (*Quantity) CanonicalizeBytes 

func (q *Quantity) CanonicalizeBytes(out []byte) (result, suffix []byte)

CanonicalizeBytes returns the canonical form of q and its suffix (see comment on Quantity).

Note about BinarySI:

  • If q.Format is set to BinarySI and q.Amount represents a non-zero value between -1 and +1, it will be emitted as if q.Format were DecimalSI.
  • Otherwise, if q.Format is set to BinarySI, frational parts of q.Amount will be rounded up. (1.1i becomes 2i.)

func (*Quantity) Cmp 

func (q *Quantity) Cmp(y Quantity) int

Cmp returns 0 if the quantity is equal to y, -1 if the quantity is less than y, or 1 if the quantity is greater than y.

func (*Quantity) CmpInt64 

func (q *Quantity) CmpInt64(y int64) int

CmpInt64 returns 0 if the quantity is equal to y, -1 if the quantity is less than y, or 1 if the quantity is greater than y.

func (*Quantity) Copy 

func (q *Quantity) Copy() *Quantity

Copy is a convenience function that makes a deep copy for you. Non-deep copies of quantities share pointers and you will regret that.

func (*Quantity) IsZero 

func (q *Quantity) IsZero() bool

IsZero returns true if the quantity is equal to zero.

func (Quantity) MarshalJSON 

func (q Quantity) MarshalJSON() ([]byte, error)

MarshalJSON implements the json.Marshaller interface.

func (*Quantity) MilliValue 

func (q *Quantity) MilliValue() int64

MilliValue returns the value of ceil(q * 1000); this could overflow an int64; if that's a concern, call Value() first to verify the number is small enough.

func (*Quantity) Neg 

func (q *Quantity) Neg()

Neg sets quantity to be the negative value of itself.

func (*Quantity) RoundUp 

func (q *Quantity) RoundUp(scale Scale) bool

RoundUp updates the quantity to the provided scale, ensuring that the value is at least 1. False is returned if the rounding operation resulted in a loss of precision. Negative numbers are rounded away from zero (-9 scale 1 rounds to -10).

func (*Quantity) ScaledValue 

func (q *Quantity) ScaledValue(scale Scale) int64

ScaledValue returns the value of ceil(q * 10^scale); this could overflow an int64. To detect overflow, call Value() first and verify the expected magnitude.

func (*Quantity) Set 

func (q *Quantity) Set(value int64)

Set sets q's value to be value.

func (*Quantity) SetMilli 

func (q *Quantity) SetMilli(value int64)

SetMilli sets q's value to be value * 1/1000.

func (*Quantity) SetScaled 

func (q *Quantity) SetScaled(value int64, scale Scale)

SetScaled sets q's value to be value * 10^scale

func (*Quantity) Sign 

func (q *Quantity) Sign() int

Sign returns 0 if the quantity is zero, -1 if the quantity is less than zero, or 1 if the quantity is greater than zero.

func (*Quantity) String 

func (q *Quantity) String() string

String formats the Quantity as a string, caching the result if not calculated. String is an expensive operation and caching this result significantly reduces the cost of normal parse / marshal operations on Quantity.

func (*Quantity) Sub 

func (q *Quantity) Sub(y Quantity)

Sub subtracts the provided quantity from the current value in place. If the current value is zero, the format of the quantity will be updated to the format of y.

func (*Quantity) ToDec 

func (q *Quantity) ToDec() *Quantity

ToDec promotes the quantity in place to use an inf.Dec representation and returns itself.

func (*Quantity) UnmarshalJSON 

func (q *Quantity) UnmarshalJSON(value []byte) error

UnmarshalJSON implements the json.Unmarshaller interface. TODO: Remove support for leading/trailing whitespace

func (*Quantity) Value 

func (q *Quantity) Value() int64

Value returns the value of q; any fractional part will be lost.

type Scale 

type Scale int32

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. 

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
)

Source Files

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