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use rounding_modes::RoundingMode;
use std::str::FromStr;
impl FromStr for RoundingMode {
type Err = String;
/// Converts a string to a [`RoundingMode`].
///
/// If the string does not represent a valid [`RoundingMode`], an `Err` is returned with the
/// unparseable string.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ = `src.len()`.
///
/// The worst case occurs when the input string is invalid and must be copied into an `Err`.
///
/// # Examples
/// ```
/// use malachite_base::rounding_modes::RoundingMode;
/// use std::str::FromStr;
///
/// assert_eq!(RoundingMode::from_str("Down"), Ok(RoundingMode::Down));
/// assert_eq!(RoundingMode::from_str("Up"), Ok(RoundingMode::Up));
/// assert_eq!(RoundingMode::from_str("Floor"), Ok(RoundingMode::Floor));
/// assert_eq!(RoundingMode::from_str("Ceiling"), Ok(RoundingMode::Ceiling));
/// assert_eq!(RoundingMode::from_str("Nearest"), Ok(RoundingMode::Nearest));
/// assert_eq!(RoundingMode::from_str("Exact"), Ok(RoundingMode::Exact));
/// assert_eq!(RoundingMode::from_str("abc"), Err("abc".to_string()));
/// ```
#[inline]
fn from_str(src: &str) -> Result<RoundingMode, String> {
match src {
"Down" => Ok(RoundingMode::Down),
"Up" => Ok(RoundingMode::Up),
"Floor" => Ok(RoundingMode::Floor),
"Ceiling" => Ok(RoundingMode::Ceiling),
"Nearest" => Ok(RoundingMode::Nearest),
"Exact" => Ok(RoundingMode::Exact),
_ => Err(src.to_string()),
}
}
}