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tariff

package module

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Versions in this module

v0

v0.2.0

Jul 22, 2026

Changes in this version

+ var ErrBadBalance = errors.New("tariff: invalid balance")

+ var ErrBadBasis = errors.New("tariff: unknown proration basis")

+ var ErrBadDiscount = errors.New("tariff: invalid discount")

+ var ErrBadFloor = errors.New("tariff: invalid minimum charge")

+ var ErrBadPeriod = errors.New("tariff: invalid billing period")

+ var ErrBadWindow = errors.New("tariff: invalid proration window")

+ var ErrCurrencyMismatch = errors.New("tariff: currency mismatch")

+ var ErrNegativeAmount = errors.New("tariff: negative amount")

+ var ErrNilStep = errors.New("tariff: nil step")

+ func NextBoundary(anchor, from time.Time, unit CycleUnit) time.Time

+ func NextCalendarBoundary(from time.Time, unit CycleUnit) time.Time

+ func Prorate(amount int64, cur Currency, frac *big.Rat) (int64, error)

+ type Basis uint8

+ const ProrateByDay

+ const ProrateBySecond

+ func (b Basis) String() string

+ type CycleUnit uint8

+ const Monthly

+ const Yearly

+ func (u CycleUnit) String() string

+ type Invoice struct

+ Currency Currency

+ Lines []Line

+ Subtotal int64

+ Total int64

+ func Compose(cur Currency, steps ...Step) (Invoice, error)

type Line

+ Label string

+ type Period struct

+ End time.Time

+ Start time.Time

+ func (p Period) Fraction(from, to time.Time, b Basis) (*big.Rat, error)

+ type Proration struct

+ Charge int64

+ Credit int64

+ Net int64

+ func Change(oldAmount, newAmount int64, cur Currency, p Period, at time.Time, b Basis) (Proration, error)

+ type Step interface

+ func AmountOff(minor int64, label string) Step

+ func Charged(c Charge, quantity int64) Step

+ func DrawCommitment(balance *int64, label string) Step

+ func DrawCredit(balance *int64, label string) Step

+ func MinimumCharge(floor int64, label string) Step

+ func PercentOff(pct *big.Rat, label string) Step

v0.1.0

Jul 21, 2026

Changes in this version

+ var ErrBadAllocation = errors.New("tariff: invalid allocation")

+ var ErrBadAllowance = errors.New("tariff: negative free allowance")

+ var ErrBadCurrency = errors.New("tariff: invalid currency")

+ var ErrBadPackage = errors.New("tariff: invalid package configuration")

+ var ErrEmptyTiers = errors.New("tariff: no tiers")

+ var ErrNegativeQuantity = errors.New("tariff: negative quantity")

+ var ErrNoRate = errors.New("tariff: missing or invalid rate")

+ var ErrOverflow = errors.New("tariff: amount overflows int64 minor units")

+ var ErrTierOrder = errors.New("tariff: tiers out of order")

+ var ErrUnknownModel = errors.New("tariff: unknown rating model")

+ func Allocate(total int64, ratios []int64) ([]int64, error)

+ type Charge struct

+ Currency Currency

+ FlatFee int64

+ FreeAllowance int64

+ Model Model

+ PackagePrice int64

+ PackageSize int64

+ Tiers []Tier

+ UnitRate *big.Rat

+ func (c Charge) Rate(quantity int64) (Result, error)

+ type Currency struct

+ Code string

+ Decimals int

+ Rounding RoundingMode

+ func JPY(r RoundingMode) Currency

+ func KWD(r RoundingMode) Currency

+ func USD(r RoundingMode) Currency

+ func (c Currency) Format(minor int64) string

+ type Line struct

+ Quantity int64

+ Rate *big.Rat

+ Subtotal int64

+ type Model uint8

+ const Graduated

+ const Package

+ const PerUnit

+ const Stairstep

+ const Volume

+ func (m Model) String() string

+ type Result struct

+ Lines []Line

+ Total int64

+ type RoundingMode uint8

+ const RoundCeil

+ const RoundFloor

+ const RoundHalfEven

+ const RoundHalfUp

+ const RoundingUnspecified

+ func (m RoundingMode) String() string

+ type Tier struct

+ FlatRate int64

+ Last bool

+ UnitRate *big.Rat

+ UpTo int64