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https://github.com/nikolaydubina/fpmoney
🧧 Fixed-Point Decimal Money
https://github.com/nikolaydubina/fpmoney
benchmarks decimal decimals encoding fixed-point go golang money vocabulary
Last synced: about 2 months ago
JSON representation
🧧 Fixed-Point Decimal Money
- Host: GitHub
- URL: https://github.com/nikolaydubina/fpmoney
- Owner: nikolaydubina
- License: mit
- Created: 2022-06-11T04:03:58.000Z (over 2 years ago)
- Default Branch: master
- Last Pushed: 2024-09-11T09:14:37.000Z (3 months ago)
- Last Synced: 2024-10-29T22:54:01.689Z (about 2 months ago)
- Topics: benchmarks, decimal, decimals, encoding, fixed-point, go, golang, money, vocabulary
- Language: Go
- Homepage:
- Size: 865 KB
- Stars: 29
- Watchers: 3
- Forks: 1
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
- Citation: CITATION.cff
- Codeowners: .github/CODEOWNERS
- Security: SECURITY.md
Awesome Lists containing this project
- awesome-go - fpmoney - Fast and simple ISO4217 fixed-point decimal money. (Financial / Search and Analytic Databases)
- awesome-go-extra - fpmoney - Point Decimal Money|7|0|2|2022-06-11T04:03:58Z|2022-07-04T01:59:27Z| (Financial / Advanced Console UIs)
README
## 🧧 Fixed-Point Decimal Money
[](https://codecov.io/gh/nikolaydubina/fpmoney)
[](https://goreportcard.com/report/github.com/nikolaydubina/fpmoney)
[](https://pkg.go.dev/github.com/nikolaydubina/fpmoney)
[](https://github.com/avelino/awesome-go)
[](https://securityscorecards.dev/viewer/?uri=github.com/nikolaydubina/fpmoney)
> _**Be Precise:** using floats to represent currency is almost criminal. — Robert.C.Martin, "Clean Code" p.301_
* as fast as `int64`
* no `float` in parsing nor printing, does not leak precision
* `ISO 4217` currency
* block mismatched currency arithmetics
* 100 LOC
* fuzz tests
```go
var BuySP500Price = fpmoney.FromInt(9000, fpmoney.SGD)
input := []byte(`{"sp500": {"amount": 9000.02, "currency": "SGD"}}`)
type Stonks struct {
SP500 fpmoney.Amount `json:"sp500"`
}
var v Stonks
if err := json.Unmarshal(input, &v); err != nil {
log.Fatal(err)
}
amountToBuy := fpmoney.FromInt(0, fpmoney.SGD)
if v.SP500.GreaterThan(BuySP500Price) {
amountToBuy = amountToBuy.Add(v.SP500.Mul(2))
}
fmt.Println(amountToBuy)
// Output: 18000.04 SGD
```
### Ultra Small Fractions
Some denominations have very low fractions.
Storing them `int64` you would get.
- `BTC` _satoshi_ is `1 BTC = 100,000,000 satoshi`, which is still enough for ~`92,233,720,368 BTC`.
- `ETH` _wei_ is `1 ETH = 1,000,000,000,000,000,000 wei`, which is ~`9 ETH`. If you deal with _wei_, you may consider `bigint` or multiple `int64`. In fact, official Ethereum code is in Go and it is using bigint ([code](https://github.com/ethereum/go-ethereum/blob/master/params/denomination.go)).
### Benchmarks
```bash
$ go test -bench=. -benchmem . > fpmoney.bench
$ go test -bench=. -benchmem ./internal/bench/float32 > float32.bench
$ go test -bench=. -benchmem ./internal/bench/int > int.bench
$ benchstat -split="XYZ" int.bench float32.bench fpmoney.bench
name \ time/op int.bench float32.bench fpmoney.bench
JSONUnmarshal/small-16 383ns ± 0% 408ns ± 0% 294ns ± 0%
JSONUnmarshal/large-16 436ns ± 0% 473ns ± 0% 365ns ± 0%
JSONMarshal/small-16 115ns ± 0% 158ns ± 0% 226ns ± 0%
JSONMarshal/large-16 112ns ± 0% 146ns ± 0% 272ns ± 0%
name \ alloc/op int.bench float32.bench fpmoney.bench
JSONUnmarshal/small-16 268B ± 0% 270B ± 0% 198B ± 0%
JSONUnmarshal/large-16 272B ± 0% 288B ± 0% 216B ± 0%
JSONMarshal/small-16 57.0B ± 0% 66.0B ± 0% 160.0B ± 0%
JSONMarshal/large-16 72.0B ± 0% 72.0B ± 0% 176.0B ± 0%
name \ allocs/op int.bench float32.bench fpmoney.bench
JSONUnmarshal/small-16 6.00 ± 0% 6.00 ± 0% 3.00 ± 0%
JSONUnmarshal/large-16 6.00 ± 0% 6.00 ± 0% 3.00 ± 0%
JSONMarshal/small-16 2.00 ± 0% 2.00 ± 0% 3.00 ± 0%
JSONMarshal/large-16 2.00 ± 0% 2.00 ± 0% 3.00 ± 0%
```
```bash
goos: darwin
goarch: arm64
pkg: github.com/nikolaydubina/fpmoney
BenchmarkArithmetic/add_x1-16 1000000000 0.54 ns/op 0 B/op 0 allocs/op
BenchmarkArithmetic/add_x100-16 26382420 44.42 ns/op 0 B/op 0 allocs/op
PASS
ok github.com/nikolaydubina/fpmoney 14.200s
```
## References and Related Work
- [ferdypruis/iso4217](https://github.com/ferdypruis/iso4217) was a good inspiration and reference material. it was used in early version as well. it is well maintained and fast library for currencies.
- `github.com/shopspring/decimal`: fixed precision; faster printing/parsing/arithmetics; currency handling
- `github.com/Rhymond/go-money`: does not use `float` or `interface{}` in parsing; currency is enum
- `github.com/ferdypruis/iso4217`: skipped deprecated currencies to fit into `uint8` and smaller struct size