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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:generate go run gen.go gen_common.go -output tables.go
// Package currency contains currency-related functionality.
//
// NOTE: the formatting functionality is currently under development and may
// change without notice.
package currency // import "golang.org/x/text/currency"
import (
"errors"
"sort"
"golang.org/x/text/internal/tag"
"golang.org/x/text/language"
)
// TODO:
// - language-specific currency names.
// - currency formatting.
// - currency information per region
// - register currency code (there are no private use area)
// TODO: remove Currency type from package language.
// Kind determines the rounding and rendering properties of a currency value.
type Kind struct {
rounding rounding
// TODO: formatting type: standard, accounting. See CLDR.
}
type rounding byte
const (
standard rounding = iota
cash
)
var (
// Standard defines standard rounding and formatting for currencies.
Standard Kind = Kind{rounding: standard}
// Cash defines rounding and formatting standards for cash transactions.
Cash Kind = Kind{rounding: cash}
// Accounting defines rounding and formatting standards for accounting.
Accounting Kind = Kind{rounding: standard}
)
// Rounding reports the rounding characteristics for the given currency, where
// scale is the number of fractional decimals and increment is the number of
// units in terms of 10^(-scale) to which to round to.
func (k Kind) Rounding(cur Unit) (scale, increment int) {
info := currency.Elem(int(cur.index))[3]
switch k.rounding {
case standard:
info &= roundMask
case cash:
info >>= cashShift
}
return int(roundings[info].scale), int(roundings[info].increment)
}
// Unit is an ISO 4217 currency designator.
type Unit struct {
index uint16
}
// String returns the ISO code of u.
func (u Unit) String() string {
if u.index == 0 {
return "XXX"
}
return currency.Elem(int(u.index))[:3]
}
// Amount creates an Amount for the given currency unit and amount.
func (u Unit) Amount(amount interface{}) Amount {
// TODO: verify amount is a supported number type
return Amount{amount: amount, currency: u}
}
var (
errSyntax = errors.New("currency: tag is not well-formed")
errValue = errors.New("currency: tag is not a recognized currency")
)
// ParseISO parses a 3-letter ISO 4217 currency code. It returns an error if s
// is not well-formed or not a recognized currency code.
func ParseISO(s string) (Unit, error) {
var buf [4]byte // Take one byte more to detect oversize keys.
key := buf[:copy(buf[:], s)]
if !tag.FixCase("XXX", key) {
return Unit{}, errSyntax
}
if i := currency.Index(key); i >= 0 {
if i == xxx {
return Unit{}, nil
}
return Unit{uint16(i)}, nil
}
return Unit{}, errValue
}
// MustParseISO is like ParseISO, but panics if the given currency unit
// cannot be parsed. It simplifies safe initialization of Unit values.
func MustParseISO(s string) Unit {
c, err := ParseISO(s)
if err != nil {
panic(err)
}
return c
}
// FromRegion reports the currency unit that is currently legal tender in the
// given region according to CLDR. It will return false if region currently does
// not have a legal tender.
func FromRegion(r language.Region) (currency Unit, ok bool) {
x := regionToCode(r)
i := sort.Search(len(regionToCurrency), func(i int) bool {
return regionToCurrency[i].region >= x
})
if i < len(regionToCurrency) && regionToCurrency[i].region == x {
return Unit{regionToCurrency[i].code}, true
}
return Unit{}, false
}
// FromTag reports the most likely currency for the given tag. It considers the
// currency defined in the -u extension and infers the region if necessary.
func FromTag(t language.Tag) (Unit, language.Confidence) {
if cur := t.TypeForKey("cu"); len(cur) == 3 {
c, _ := ParseISO(cur)
return c, language.Exact
}
r, conf := t.Region()
if cur, ok := FromRegion(r); ok {
return cur, conf
}
return Unit{}, language.No
}
var (
// Undefined and testing.
XXX Unit = Unit{}
XTS Unit = Unit{xts}
// G10 currencies https://en.wikipedia.org/wiki/G10_currencies.
USD Unit = Unit{usd}
EUR Unit = Unit{eur}
JPY Unit = Unit{jpy}
GBP Unit = Unit{gbp}
CHF Unit = Unit{chf}
AUD Unit = Unit{aud}
NZD Unit = Unit{nzd}
CAD Unit = Unit{cad}
SEK Unit = Unit{sek}
NOK Unit = Unit{nok}
// Additional common currencies as defined by CLDR.
BRL Unit = Unit{brl}
CNY Unit = Unit{cny}
DKK Unit = Unit{dkk}
INR Unit = Unit{inr}
RUB Unit = Unit{rub}
HKD Unit = Unit{hkd}
IDR Unit = Unit{idr}
KRW Unit = Unit{krw}
MXN Unit = Unit{mxn}
PLN Unit = Unit{pln}
SAR Unit = Unit{sar}
THB Unit = Unit{thb}
TRY Unit = Unit{try}
TWD Unit = Unit{twd}
ZAR Unit = Unit{zar}
// Precious metals.
XAG Unit = Unit{xag}
XAU Unit = Unit{xau}
XPT Unit = Unit{xpt}
XPD Unit = Unit{xpd}
)
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