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/// Extension trait to make a single number human-readable.
pub trait Smooth {
/// Returns the number rounded to the specified decimals.
///
/// # Examples
///
/// ```rust
/// # use smooth::Smooth;
/// assert_eq!(1.1111.round_to(2), 1.11);
/// assert_eq!(9.9999.round_to(2), 10.0);
/// ```
#[must_use]
fn round_to(&self, decimals: u32) -> Self;
/// Rounds the number to the specified decimals.
///
/// # Examples
///
/// ```rust
/// # use smooth::Smooth;
/// let mut n = 1.1111;
/// n.round_to_mut(2);
///
/// assert_eq!(n, 1.11);
/// ```
fn round_to_mut(&mut self, decimals: u32);
/// Returns the formatted, rounded number.
///
/// # Examples
///
/// ```rust
/// # use smooth::Smooth;
/// assert_eq!(1.0.round_to_str(2), "1");
/// assert_eq!(1.001.round_to_str(2), "1");
/// assert_eq!(1.018.round_to_str(2), "1.02");
/// assert_eq!(1.4242.round_to_str(2), "1.42");
/// ```
fn round_to_str(&self, decimals: u32) -> String;
/// Returns the smoothed number.
///
/// # Examples
///
/// ```rust
/// # use smooth::Smooth;
/// assert_eq!(0.0.smooth(), 0.0);
/// assert_eq!(0.009.smooth(), 0.01);
/// assert_eq!(1.001.smooth(), 1.0);
/// assert_eq!(10.1.smooth(), 10.1);
/// assert_eq!(1000.9.smooth(), 1001.0);
/// ```
#[must_use]
fn smooth(&self) -> Self;
/// Smoothes the number.
///
/// # Examples
///
/// ```rust
/// # use smooth::Smooth;
/// let mut n = 1.001;
/// n.smooth_mut();
///
/// assert_eq!(n, 1.0);
/// ```
fn smooth_mut(&mut self);
/// Returns the formatted, smoothed number.
///
/// # Examples
///
/// ```rust
/// # use smooth::Smooth;
/// assert_eq!(0.0.smooth_str(), "0");
/// assert_eq!(0.009.smooth_str(), "0.01");
/// assert_eq!(1.001.smooth_str(), "1");
/// assert_eq!(10.1.smooth_str(), "10.1");
/// assert_eq!(1000.9.smooth_str(), "1001");
/// ```
fn smooth_str(&self) -> String;
#[doc(hidden)]
fn trunc_digits(&self) -> u32;
}
macro_rules! smooth_impl {
($t:ty) => {
impl Smooth for $t {
fn round_to(&self, decimals: u32) -> Self {
let factor = 10_u64.pow(decimals) as Self;
(self * factor).round() / factor
}
fn round_to_mut(&mut self, decimals: u32) {
*self = self.round_to(decimals)
}
fn round_to_str(&self, decimals: u32) -> String {
format!("{}", self.round_to(decimals))
}
fn smooth(&self) -> Self {
if self.fract().abs() == 0.0 {
self.round()
} else if self.trunc().abs() == 0.0 {
self.round_to(2)
} else {
let decimals = 3_u32
.checked_sub(self.trunc_digits())
.unwrap_or_default();
self.round_to(decimals)
}
}
fn smooth_mut(&mut self) {
*self = self.smooth()
}
fn smooth_str(&self) -> String {
format!("{}", self.smooth())
}
fn trunc_digits(&self) -> u32 {
let trunc = self.trunc().abs();
// ALLOW there can only be positive, truncated values
#[allow(clippy::cast_possible_truncation)]
#[allow(clippy::cast_sign_loss)]
let ret = (trunc.log10() + 1.0).floor() as u32;
ret
}
}
};
}
smooth_impl!(f32);
smooth_impl!(f64);
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn trunc_digits() {
assert_eq!(0.0.trunc_digits(), 0);
assert_eq!(1.0.trunc_digits(), 1);
assert_eq!(10.0.trunc_digits(), 2);
assert_eq!(100.0.trunc_digits(), 3);
assert_eq!(1_000.0.trunc_digits(), 4);
assert_eq!(1_000_000.0.trunc_digits(), 7);
assert_eq!((-1_000.0).trunc_digits(), 4);
assert_eq!((-1_000_000.0).trunc_digits(), 7);
}
}