codex_protocol/
num_format.rs

1use std::sync::OnceLock;
2
3use icu_decimal::DecimalFormatter;
4use icu_decimal::input::Decimal;
5use icu_decimal::options::DecimalFormatterOptions;
6use icu_locale_core::Locale;
7
8fn make_local_formatter() -> Option<DecimalFormatter> {
9    let loc: Locale = sys_locale::get_locale()?.parse().ok()?;
10    DecimalFormatter::try_new(loc.into(), DecimalFormatterOptions::default()).ok()
11}
12
13fn make_en_us_formatter() -> DecimalFormatter {
14    #![allow(clippy::expect_used)]
15    let loc: Locale = "en-US".parse().expect("en-US wasn't a valid locale");
16    DecimalFormatter::try_new(loc.into(), DecimalFormatterOptions::default())
17        .expect("en-US wasn't a valid locale")
18}
19
20fn formatter() -> &'static DecimalFormatter {
21    static FORMATTER: OnceLock<DecimalFormatter> = OnceLock::new();
22    FORMATTER.get_or_init(|| make_local_formatter().unwrap_or_else(make_en_us_formatter))
23}
24
25/// Format an i64 with locale-aware digit separators (e.g. "12345" -> "12,345"
26/// for en-US).
27pub fn format_with_separators(n: i64) -> String {
28    formatter().format(&Decimal::from(n)).to_string()
29}
30
31fn format_si_suffix_with_formatter(n: i64, formatter: &DecimalFormatter) -> String {
32    let n = n.max(0);
33    if n < 1000 {
34        return formatter.format(&Decimal::from(n)).to_string();
35    }
36
37    // Format `n / scale` with the requested number of fractional digits.
38    let format_scaled = |n: i64, scale: i64, frac_digits: u32| -> String {
39        let value = n as f64 / scale as f64;
40        let scaled: i64 = (value * 10f64.powi(frac_digits as i32)).round() as i64;
41        let mut dec = Decimal::from(scaled);
42        dec.multiply_pow10(-(frac_digits as i16));
43        formatter.format(&dec).to_string()
44    };
45
46    const UNITS: [(i64, &str); 3] = [(1_000, "K"), (1_000_000, "M"), (1_000_000_000, "G")];
47    let f = n as f64;
48    for &(scale, suffix) in &UNITS {
49        if (100.0 * f / scale as f64).round() < 1000.0 {
50            return format!("{}{}", format_scaled(n, scale, 2), suffix);
51        } else if (10.0 * f / scale as f64).round() < 1000.0 {
52            return format!("{}{}", format_scaled(n, scale, 1), suffix);
53        } else if (f / scale as f64).round() < 1000.0 {
54            return format!("{}{}", format_scaled(n, scale, 0), suffix);
55        }
56    }
57
58    // Above 1000G, keep whole‑G precision.
59    format!(
60        "{}G",
61        format_with_separators(((n as f64) / 1e9).round() as i64)
62    )
63}
64
65/// Format token counts to 3 significant figures, using base-10 SI suffixes.
66///
67/// Examples (en-US):
68///   - 999 -> "999"
69///   - 1200 -> "1.20K"
70///   - 123456789 -> "123M"
71pub fn format_si_suffix(n: i64) -> String {
72    format_si_suffix_with_formatter(n, formatter())
73}
74
75#[cfg(test)]
76mod tests {
77    use super::*;
78
79    #[test]
80    fn kmg() {
81        let formatter = make_en_us_formatter();
82        let fmt = |n: i64| format_si_suffix_with_formatter(n, &formatter);
83        assert_eq!(fmt(0), "0");
84        assert_eq!(fmt(999), "999");
85        assert_eq!(fmt(1_000), "1.00K");
86        assert_eq!(fmt(1_200), "1.20K");
87        assert_eq!(fmt(10_000), "10.0K");
88        assert_eq!(fmt(100_000), "100K");
89        assert_eq!(fmt(999_500), "1.00M");
90        assert_eq!(fmt(1_000_000), "1.00M");
91        assert_eq!(fmt(1_234_000), "1.23M");
92        assert_eq!(fmt(12_345_678), "12.3M");
93        assert_eq!(fmt(999_950_000), "1.00G");
94        assert_eq!(fmt(1_000_000_000), "1.00G");
95        assert_eq!(fmt(1_234_000_000), "1.23G");
96        // Above 1000G we keep whole‑G precision (no higher unit supported here).
97        assert_eq!(fmt(1_234_000_000_000), "1,234G");
98    }
99}
codex_protocol/num_format.rs

codex_protocol/
num_format.rs
