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fix(core): format_units overflow (#1894) 

* fix(core): format_units overflow

* fix: formatting

* remove dbg

* add comment and rerun ci

* tests

* fix test

* refactor: move magic nums to consts

Co-authored-by: Georgios Konstantopoulos <me@gakonst.com>
This commit is contained in:
DaniPopes 2022-11-27 21:27:27 +01:00 committed by GitHub
parent b0ef1343dd
commit 97eecaf03b
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1 changed files with 49 additions and 20 deletions
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69
ethers-core/src/utils/mod.rs
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@ -41,6 +41,11 @@ use std::{
};
use thiserror::Error;
/// I256 overflows for numbers wider than 77 units.
const OVERFLOW_I256_UNITS: usize = 77;
/// U256 overflows for numbers wider than 78 units.
const OVERFLOW_U256_UNITS: usize = 78;
/// Re-export of serde-json
#[doc(hidden)]
pub mod __serde_json {
@ -158,29 +163,35 @@ where
T: Into<ParseUnits>,
K: TryInto<Units, Error = ConversionError>,
{
let units = units.try_into()?;
match amount.into() {
let units: usize = units.try_into()?.into();
let amount = amount.into();
match amount {
// 2**256 ~= 1.16e77
ParseUnits::U256(_) if units >= OVERFLOW_U256_UNITS => {
return Err(ConversionError::ParseOverflow)
}
// 2**255 ~= 5.79e76
ParseUnits::I256(_) if units >= OVERFLOW_I256_UNITS => {
return Err(ConversionError::ParseOverflow)
}
_ => {}
};
let exp10 = U256::exp10(units);
// `decimals` are formatted twice because U256 does not support alignment (`:0>width`).
match amount {
ParseUnits::U256(amount) => {
let amount_decimals = amount % U256::from(10_u128.pow(units.as_num()));
let amount_integer = amount / U256::from(10_u128.pow(units.as_num()));
Ok(format!(
"{}.{:0width$}",
amount_integer,
amount_decimals.as_u128(),
width = units.as_num() as usize
))
let integer = amount / exp10;
let decimals = (amount % exp10).to_string();
Ok(format!("{integer}.{decimals:0>units$}"))
}
ParseUnits::I256(amount) => {
let exp10 = I256::from_raw(exp10);
let sign = if amount.is_negative() { "-" } else { "" };
let amount_decimals = amount % I256::from(10_u128.pow(units.as_num()));
let amount_integer = amount / I256::from(10_u128.pow(units.as_num()));
Ok(format!(
"{}{}.{:0width$}",
sign,
amount_integer.twos_complement(),
amount_decimals.twos_complement().as_u128(),
width = units.as_num() as usize
))
let integer = (amount / exp10).twos_complement();
let decimals = ((amount % exp10).twos_complement()).to_string();
Ok(format!("{sign}{integer}.{decimals:0>units$}"))
}
}
}
@ -546,7 +557,7 @@ mod tests {
format_units(U256::from_dec_str("1005633240123456789").unwrap(), "ether").unwrap();
assert_eq!(eth, "1.005633240123456789");
let eth = format_units(255u8, 4).unwrap();
let eth = format_units(u8::MAX, 4).unwrap();
assert_eq!(eth, "0.0255");
let eth = format_units(u16::MAX, "ether").unwrap();
@ -562,6 +573,15 @@ mod tests {
let eth = format_units(u128::MAX, 36).unwrap();
assert_eq!(eth, "340.282366920938463463374607431768211455");
let eth = format_units(U256::MAX, 77).unwrap();
assert_eq!(
eth,
"1.15792089237316195423570985008687907853269984665640564039457584007913129639935"
);
let err = format_units(U256::MAX, 78).unwrap_err();
assert!(matches!(err, ConversionError::ParseOverflow));
}
#[test]
@ -599,6 +619,15 @@ mod tests {
let eth = format_units(i128::MIN, 36).unwrap();
assert_eq!(eth, "-170.141183460469231731687303715884105728");
let eth = format_units(I256::MIN, 76).unwrap();
assert_eq!(
eth,
"-5.7896044618658097711785492504343953926634992332820282019728792003956564819968"
);
let err = format_units(I256::MIN, 77).unwrap_err();
assert!(matches!(err, ConversionError::ParseOverflow));
}
#[test]