The API provides a light-weight alternative to arbitrary-precision arithmetic.
The const generics for base-ten exponents fix the computation steps involved
at compile time. You basically get the speed of 64-bit primitives combined with
the safety from big-number implementations.
let cents = b10::BaseCount::<-2>::from(199);
assert_eq!("€ 1.99", format!("€ {cents}"));All operation is lossless by design unless explicitly stated otherwise in the name of the respective method. The lossless guarantee applies to parsing and formatting too. Can't read nor write digits beyond the base resolution.
// metric prefixes
use b10::{Milli, Nano, Pico};
let mA = Milli::from(100);
let ns = Nano::from(4);
// multiply into another base
let (pC, overflow):(Pico, Pico) = mA.mul(ns);
if overflow != Pico::ZERO {
panic!("product exceeds 2⁶⁴ − 1 pico");
}
// pretty formatting options
assert_eq!(
"0.100 × 0.000000004 = 0.000000000400",
format!("{mA} × {ns} = {pC}"),
);
assert_eq!(
"100E-3 × 4E-9 = 400E-12",
format!("{mA:E} × {ns:E} = {pC:E}"),
);
assert_eq!(
"100 mA × 4 ns = 400 pC",
format!("{mA:#}A × {ns:#}s = {pC:#}C"),
);Formatting and parsing performance is slighty faster than the Display and FromStr traits from the standard library.
test fmt_tests::format_exponent_kilo ... bench: 7.81 ns/iter (+/- 0.07)
test fmt_tests::format_exponent_u64 ... bench: 9.68 ns/iter (+/- 0.36)
test fmt_tests::format_fraction_milli ... bench: 7.82 ns/iter (+/- 0.05)
test fmt_tests::format_fraction_u64 ... bench: 19.87 ns/iter (+/- 0.37)
test fmt_tests::format_integer_natural ... bench: 6.72 ns/iter (+/- 0.07)
test fmt_tests::format_integer_u64 ... bench: 8.59 ns/iter (+/- 0.07)
test fmt_tests::format_sub_zero_quecto ... bench: 7.50 ns/iter (+/- 0.03)
test fmt_tests::format_sub_zero_u64 ... bench: 22.50 ns/iter (+/- 0.17)
test text_tests::parse_exponents_as_f64 ... bench: 9.14 ns/iter (+/- 0.27)
test text_tests::parse_exponents_as_pico ... bench: 7.81 ns/iter (+/- 0.04)
test text_tests::parse_fractions_as_f64 ... bench: 7.78 ns/iter (+/- 0.04)
test text_tests::parse_fractions_as_nano ... bench: 5.39 ns/iter (+/- 0.09)
test text_tests::parse_integers_as_centi ... bench: 3.75 ns/iter (+/- 0.01)
test text_tests::parse_integers_as_natural ... bench: 3.75 ns/iter (+/- 0.03)
test text_tests::parse_integers_as_u64 ... bench: 3.12 ns/iter (+/- 0.01)
This is free and unencumbered software released into the public domain.