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Add Decimal{,256}::to_uint_floor and ::to_uint_ceil #1603

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merged 5 commits into from
Jan 30, 2023
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Add Decimal{,256}::to_uint_floor and ::to_uint_ceil #1603

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4e688ba
Add to_uint_floor, to_uint_ceil
webmaster128 Jan 26, 2023
2bcc2d1
Add unit tests
webmaster128 Jan 26, 2023
3b7b3a4
Implement to_uint_ceil without modulo operation
webmaster128 Jan 30, 2023
a31e81f
Test to_uint_floor for value < 1
webmaster128 Jan 30, 2023
6ca600b
Test compatibility with old workaround
webmaster128 Jan 30, 2023
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103 changes: 103 additions & 0 deletions packages/std/src/math/decimal.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -357,6 +357,58 @@ impl Decimal {
Err(_) => Self::MAX,
}
}

/// Converts this decimal to an unsigned integer by truncating
/// the fractional part, e.g. 22.5 becomes 22.
///
/// ## Examples
///
/// ```
/// use std::str::FromStr;
/// use cosmwasm_std::{Decimal, Uint128};
///
/// let d = Decimal::from_str("12.345").unwrap();
/// assert_eq!(d.to_uint_floor(), Uint128::new(12));
///
/// let d = Decimal::from_str("12.999").unwrap();
/// assert_eq!(d.to_uint_floor(), Uint128::new(12));
///
/// let d = Decimal::from_str("75.0").unwrap();
/// assert_eq!(d.to_uint_floor(), Uint128::new(75));
/// ```
pub fn to_uint_floor(self) -> Uint128 {
self.0 / Self::DECIMAL_FRACTIONAL
}

/// Converts this decimal to an unsigned integer by rounting up
/// to the next integer, e.g. 22.3 becomes 23.
///
/// ## Examples
///
/// ```
/// use std::str::FromStr;
/// use cosmwasm_std::{Decimal, Uint128};
///
/// let d = Decimal::from_str("12.345").unwrap();
/// assert_eq!(d.to_uint_ceil(), Uint128::new(13));
///
/// let d = Decimal::from_str("12.999").unwrap();
/// assert_eq!(d.to_uint_ceil(), Uint128::new(13));
///
/// let d = Decimal::from_str("75.0").unwrap();
/// assert_eq!(d.to_uint_ceil(), Uint128::new(75));
/// ```
pub fn to_uint_ceil(self) -> Uint128 {
// Using `q = 1 + ((x - 1) / y); // if x != 0` with unsigned integers x, y, q
// from https://stackoverflow.com/a/2745086/2013738. We know `x + y` CAN overflow.
let x = self.0;
let y = Self::DECIMAL_FRACTIONAL;
if x.is_zero() {
Uint128::zero()
} else {
Uint128::one() + ((x - Uint128::one()) / y)
}
}
}

impl Fraction<Uint128> for Decimal {
Expand Down Expand Up @@ -2002,6 +2054,57 @@ mod tests {
));
}

#[test]
fn decimal_to_uint_floor_works() {
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Are those tests even needed? You have them in examples which makes them automatically tests (unless we disabled this behaviour for some reason? I don't think so). To me it is just a duplicate.

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Yeah, some are duplicates because I wrote the examples first. But I think it's good to have both to be able to optimize examples for teaching and tests for coverage long term.

You have them in examples which makes them automatically tests (unless we disabled this behaviour for some reason? I don't think so).

Yeah, doc tests are running as usual here

let d = Decimal::from_str("12.000000000000000001").unwrap();
assert_eq!(d.to_uint_floor(), Uint128::new(12));
let d = Decimal::from_str("12.345").unwrap();
assert_eq!(d.to_uint_floor(), Uint128::new(12));
let d = Decimal::from_str("12.999").unwrap();
assert_eq!(d.to_uint_floor(), Uint128::new(12));
let d = Decimal::from_str("0.98451384").unwrap();
assert_eq!(d.to_uint_floor(), Uint128::new(0));

let d = Decimal::from_str("75.0").unwrap();
assert_eq!(d.to_uint_floor(), Uint128::new(75));
let d = Decimal::from_str("0.0").unwrap();
assert_eq!(d.to_uint_floor(), Uint128::new(0));

let d = Decimal::MAX;
assert_eq!(d.to_uint_floor(), Uint128::new(340282366920938463463));

// Does the same as the old workaround `Uint128::one() * my_decimal`.
// This block can be deleted as part of https://github.com/CosmWasm/cosmwasm/issues/1485.
let tests = vec![
Decimal::from_str("12.345").unwrap(),
Decimal::from_str("0.98451384").unwrap(),
Decimal::from_str("178.0").unwrap(),
Decimal::MIN,
Decimal::MAX,
];
for my_decimal in tests.into_iter() {
assert_eq!(my_decimal.to_uint_floor(), Uint128::one() * my_decimal);
}
}

#[test]
fn decimal_to_uint_ceil_works() {
let d = Decimal::from_str("12.000000000000000001").unwrap();
assert_eq!(d.to_uint_ceil(), Uint128::new(13));
let d = Decimal::from_str("12.345").unwrap();
assert_eq!(d.to_uint_ceil(), Uint128::new(13));
let d = Decimal::from_str("12.999").unwrap();
assert_eq!(d.to_uint_ceil(), Uint128::new(13));

let d = Decimal::from_str("75.0").unwrap();
assert_eq!(d.to_uint_ceil(), Uint128::new(75));
let d = Decimal::from_str("0.0").unwrap();
assert_eq!(d.to_uint_ceil(), Uint128::new(0));

let d = Decimal::MAX;
assert_eq!(d.to_uint_ceil(), Uint128::new(340282366920938463464));
}

#[test]
fn decimal_partial_eq() {
let test_cases = [
Expand Down
111 changes: 111 additions & 0 deletions packages/std/src/math/decimal256.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -374,6 +374,58 @@ impl Decimal256 {
Err(_) => Self::MAX,
}
}

/// Converts this decimal to an unsigned integer by truncating
/// the fractional part, e.g. 22.5 becomes 22.
///
/// ## Examples
///
/// ```
/// use std::str::FromStr;
/// use cosmwasm_std::{Decimal256, Uint256};
///
/// let d = Decimal256::from_str("12.345").unwrap();
/// assert_eq!(d.to_uint_floor(), Uint256::from(12u64));
///
/// let d = Decimal256::from_str("12.999").unwrap();
/// assert_eq!(d.to_uint_floor(), Uint256::from(12u64));
///
/// let d = Decimal256::from_str("75.0").unwrap();
/// assert_eq!(d.to_uint_floor(), Uint256::from(75u64));
/// ```
pub fn to_uint_floor(self) -> Uint256 {
self.0 / Self::DECIMAL_FRACTIONAL
}

/// Converts this decimal to an unsigned integer by rounting up
/// to the next integer, e.g. 22.3 becomes 23.
///
/// ## Examples
///
/// ```
/// use std::str::FromStr;
/// use cosmwasm_std::{Decimal256, Uint256};
///
/// let d = Decimal256::from_str("12.345").unwrap();
/// assert_eq!(d.to_uint_ceil(), Uint256::from(13u64));
///
/// let d = Decimal256::from_str("12.999").unwrap();
/// assert_eq!(d.to_uint_ceil(), Uint256::from(13u64));
///
/// let d = Decimal256::from_str("75.0").unwrap();
/// assert_eq!(d.to_uint_ceil(), Uint256::from(75u64));
/// ```
pub fn to_uint_ceil(self) -> Uint256 {
// Using `q = 1 + ((x - 1) / y); // if x != 0` with unsigned integers x, y, q
// from https://stackoverflow.com/a/2745086/2013738. We know `x + y` CAN overflow.
let x = self.0;
let y = Self::DECIMAL_FRACTIONAL;
if x.is_zero() {
Uint256::zero()
} else {
Uint256::one() + ((x - Uint256::one()) / y)
}
}
}

impl Fraction<Uint256> for Decimal256 {
Expand Down Expand Up @@ -2149,6 +2201,65 @@ mod tests {
assert_eq!(Decimal256::MAX.checked_ceil(), Err(RoundUpOverflowError));
}

#[test]
fn decimal256_to_uint_floor_works() {
let d = Decimal256::from_str("12.000000000000000001").unwrap();
assert_eq!(d.to_uint_floor(), Uint256::from_u128(12));
let d = Decimal256::from_str("12.345").unwrap();
assert_eq!(d.to_uint_floor(), Uint256::from_u128(12));
let d = Decimal256::from_str("12.999").unwrap();
assert_eq!(d.to_uint_floor(), Uint256::from_u128(12));
let d = Decimal256::from_str("0.98451384").unwrap();
assert_eq!(d.to_uint_floor(), Uint256::from_u128(0));

let d = Decimal256::from_str("75.0").unwrap();
assert_eq!(d.to_uint_floor(), Uint256::from_u128(75));
let d = Decimal256::from_str("0.0").unwrap();
assert_eq!(d.to_uint_floor(), Uint256::from_u128(0));

let d = Decimal256::MAX;
assert_eq!(
d.to_uint_floor(),
Uint256::from_str("115792089237316195423570985008687907853269984665640564039457")
.unwrap()
);

// Does the same as the old workaround `Uint256::one() * my_decimal`.
// This block can be deleted as part of https://github.com/CosmWasm/cosmwasm/issues/1485.
let tests = vec![
Decimal256::from_str("12.345").unwrap(),
Decimal256::from_str("0.98451384").unwrap(),
Decimal256::from_str("178.0").unwrap(),
Decimal256::MIN,
Decimal256::MAX,
];
for my_decimal in tests.into_iter() {
assert_eq!(my_decimal.to_uint_floor(), Uint256::one() * my_decimal);
}
}

#[test]
fn decimal256_to_uint_ceil_works() {
let d = Decimal256::from_str("12.000000000000000001").unwrap();
assert_eq!(d.to_uint_ceil(), Uint256::from_u128(13));
let d = Decimal256::from_str("12.345").unwrap();
assert_eq!(d.to_uint_ceil(), Uint256::from_u128(13));
let d = Decimal256::from_str("12.999").unwrap();
assert_eq!(d.to_uint_ceil(), Uint256::from_u128(13));

let d = Decimal256::from_str("75.0").unwrap();
assert_eq!(d.to_uint_ceil(), Uint256::from_u128(75));
let d = Decimal256::from_str("0.0").unwrap();
assert_eq!(d.to_uint_ceil(), Uint256::from_u128(0));

let d = Decimal256::MAX;
assert_eq!(
d.to_uint_ceil(),
Uint256::from_str("115792089237316195423570985008687907853269984665640564039458")
.unwrap()
);
}

#[test]
fn decimal256_partial_eq() {
let test_cases = [
Expand Down