df_hyperliquid_core/utils/
figure.rs

1//! A few reads send a number as a bare JSON float rather than a decimal
2//! string: `vaultDetails` writes `"apr":0.037456007367970744`. serde_json
3//! would put that through an f64 and keep whatever digits came back out; this
4//! reads the text the venue wrote instead.
5
6use std::fmt;
7
8use serde::{Deserialize, Deserializer, de};
9use serde_json::value::RawValue;
10
11use crate::utils::dec::Dec;
12
13/// A number exactly as the venue wrote it, float or string. No f64 holds it.
14#[derive(Debug, Clone, PartialEq, Eq, Hash)]
15pub struct Figure(String);
16
17impl Figure {
18    /// The digits as written: `0.037456007367970744`, `1e-7`, `0.0`.
19    #[must_use]
20    pub fn as_str(&self) -> &str {
21        &self.0
22    }
23
24    /// The value, an exponent applied exactly. Past eighteen places it is the
25    /// nearest at eighteen; `None` past what a [`Dec`] counts.
26    #[must_use]
27    pub fn to_dec(&self) -> Option<Dec> {
28        let (mantissa, exponent) = match self.0.split_once(['e', 'E']) {
29            Some((mantissa, exponent)) => (mantissa, exponent.parse::<i32>().ok()?),
30            None => (self.0.as_str(), 0),
31        };
32        let mut value = Dec::parse(mantissa).ok()?;
33        let mut shift = exponent.unsigned_abs();
34        while shift > 0 {
35            let step = shift.min(18);
36            let factor = match exponent < 0 {
37                true => Dec::new(1, step)?,
38                false => Dec::new(10i128.checked_pow(step)?, 0)?,
39            };
40            value = value.checked_mul(factor)?;
41            shift -= step;
42        }
43        Some(value)
44    }
45
46    fn read(text: &str) -> Option<Figure> {
47        let plain = |text: &str| {
48            !text.is_empty()
49                && text.bytes().all(|byte| byte.is_ascii_digit() || matches!(byte, b'-' | b'+' | b'.' | b'e' | b'E'))
50        };
51        match text.strip_prefix('"') {
52            Some(_) => serde_json::from_str::<String>(text).ok().filter(|inner| plain(inner)).map(Figure),
53            None => plain(text).then(|| Figure(text.to_owned())),
54        }
55    }
56}
57
58impl fmt::Display for Figure {
59    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
60        f.write_str(&self.0)
61    }
62}
63
64/// From the raw JSON text, so it reads only through `serde_json::from_str`
65/// (which is how `info` reads), not through a `serde_json::Value`.
66impl<'de> Deserialize<'de> for Figure {
67    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
68        let raw = Box::<RawValue>::deserialize(deserializer)?;
69        Figure::read(raw.get().trim()).ok_or_else(|| de::Error::custom(format!("`{}` is not a number", raw.get())))
70    }
71}
72
73#[cfg(test)]
74#[path = "tests/figure.rs"]
75mod tests;
df_hyperliquid_core/utils/figure.rs

df_hyperliquid_core/utils/
figure.rs
