Package decimal

import "bitbucket.org/advbet/decimal"

Overview
Index

Overview

Index

type Number
func FromFloat64(f float64) (Number, error)
func FromInt(val int) Number
func FromRat(val *big.Rat, exp int) Number
func FromString(str string) (Number, error)
func New(val int64, exp int) Number
func Zero() Number
func (d Number) Add(that Number) Number
func (d Number) Cmp(n Number) int
func (d *Number) Exp() int
func (d Number) Float64() float64
func (d Number) IsZero() bool
func (d Number) MarshalJSON() ([]byte, error)
func (d Number) MarshalText() ([]byte, error)
func (d Number) Mul(that Number) Number
func (d Number) MulInt(n int) Number
func (d Number) Neg() Number
func (d Number) Rat() *big.Rat
func (d Number) Round(exp int, rule RoundRule) Number
func (d Number) ScaledVal(exp int) int64
func (d *Number) Scan(src interface{}) (err error)
func (d Number) String() string
func (d Number) Sub(that Number) Number
func (d *Number) UnmarshalJSON(data []byte) error
func (d *Number) UnmarshalText(data []byte) (err error)
func (d *Number) Val() int64
func (d Number) Value() (driver.Value, error)
type RoundRule

Package files

decimal.go float64.go

type Number

Number is a type used to store precise decimal values. It is used to store data from DECIMAL / NUMERC fields from a database without loosing precision. This type also have some helper methods for basic arithmetical operation. All except Div operation is executed without a loss of precision.

type Number struct {
    // contains filtered or unexported fields
}

func FromFloat64

func FromFloat64(f float64) (Number, error)

FromFloat64 creates new decimal value from float64.

func FromInt

func FromInt(val int) Number

FromInt creates a new instance of decimal number with an integer value and zero exponent.

func FromRat

func FromRat(val *big.Rat, exp int) Number

FromRat creates a new instance of decimal number from a Rat value with given exponent.

func FromString

func FromString(str string) (Number, error)

FromString creates a new instance of decimal number by parsing given string.

Accepted format examples: "1234", "123.456". "123.000".

Scientific notation is not supported.

func New

func New(val int64, exp int) Number

New creates a new decimal number having value of val*10^exp.

func Zero

func Zero() Number

Zero create a new decimal number that is equal to zero.

func (Number) Add

func (d Number) Add(that Number) Number

Add implements + operation for decimal numbers

func (Number) Cmp

func (d Number) Cmp(n Number) int

Cmp compares d and n and returns:

-1 if d <  n
 0 if d == n
+1 if d >  n

func (*Number) Exp

func (d *Number) Exp() int

Exp extracts private field holding current exponent value. Real decimal number value is val*10^exp.

func (Number) Float64

func (d Number) Float64() float64

Float64 retuns decimal value approximation as float64.

func (Number) IsZero

func (d Number) IsZero() bool

IsZero returns true if value of the decimal is equal to 0. It is a shortcut for executing `d.Val() == 0`.

func (Number) MarshalJSON

func (d Number) MarshalJSON() ([]byte, error)

MarshalJSON implements Marshaler interface from encoding/json package.

func (Number) MarshalText

func (d Number) MarshalText() ([]byte, error)

MarshalText function implements TextMarshaler interface from encoding package.

func (Number) Mul

func (d Number) Mul(that Number) Number

Mul implements * operation for decimal numbers

func (Number) MulInt

func (d Number) MulInt(n int) Number

MulInt calculates d * n value.

func (Number) Neg

func (d Number) Neg() Number

Neg returnds -d.

func (Number) Rat

func (d Number) Rat() *big.Rat

Rat returns a rational representation of decimal.

func (Number) Round

func (d Number) Round(exp int, rule RoundRule) Number

Round scales decimal value to an integer value with given exponent. On exponent scale-down decimal value precision is preserved, on exponent scale-up rounding with the given rounding rule is performed.

func (Number) ScaledVal

func (d Number) ScaledVal(exp int) int64

ScaledVal scales decimal number to a given exponent and and returns internal number integer value. If given exponent is higher then internal number exponent this function will loose truncated digits.

Example: number "12.99" with call ScaledVal(-4) would return 129900, with call ScaledVal(0) would return 12.

func (*Number) Scan

func (d *Number) Scan(src interface{}) (err error)

Scan implements Scanner interface database/sql encoding package.

func (Number) String

func (d Number) String() string

String function implements Stringer interface from fmt package.

func (Number) Sub

func (d Number) Sub(that Number) Number

Sub implements - operation for decimal numbers

func (*Number) UnmarshalJSON

func (d *Number) UnmarshalJSON(data []byte) error

UnmarshalJSON implements Unmarshaler interface from encoding/json package.

func (*Number) UnmarshalText

func (d *Number) UnmarshalText(data []byte) (err error)

UnmarshalText implements TextMarshaler interface from encoding package.

func (*Number) Val

func (d *Number) Val() int64

Val extracts private field holding current integer value. Real decimal number value is val*10^exp.

func (Number) Value

func (d Number) Value() (driver.Value, error)

Value implements Valuer interface from database/sql/driver package.

type RoundRule

RoundRule is enum type for specifying rounding algorithm when decimal number is scaled with loss of precision. List of supported rounding rules are listed in `Round*` consts.

type RoundRule int

List of supported rounding rules

const (
    RoundTruncate RoundRule = iota // Directed rounding towards zero
    RoundFloor                     // Directed rounding towards positive infinity
    RoundCeil                      // Directed rounding towards negative infinity
    RoundMath                      // Round to nearest, on tie round away from zero
    RoundBankers                   // Round to nearest, on tie round to even number
)

bitbucket.org/advbet/decimal

decimal