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/*! # based `based` provides support for custom single-character digits. `based` does not support multi-character digits. # Examples ``` use based::{Base, NumeralSystem}; let base16: Base = "0123456789abcdef".parse().unwrap(); let val: usize = base16.decode("10").unwrap(); assert_eq!(val, 16); assert_eq!(base16.encode(16 as usize).unwrap(), "10") ``` */ use std::num::TryFromIntError; mod single_base; pub use single_base::*; /** `StrError` is the error type produced when [`NumeralSystem::decode`](NumeralSystem::decode) encounters an unknown character or fails to convert between two integer types. */ #[derive(Debug)] pub enum StrError { /// Contains the unknown character. UnknownChar(char), Try(TryFromIntError) } impl std::fmt::Display for StrError { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { match self { StrError::UnknownChar(c) => write!(f, "Encountered char {} not in base", c), StrError::Try(t) => t.fmt(f) } } } impl std::error::Error for StrError { fn source(&self) -> Option<&(dyn std::error::Error + 'static)> { match self { StrError::UnknownChar(_) => None, StrError::Try(t) => Some(t) } } } impl From<TryFromIntError> for StrError { fn from(err: TryFromIntError) -> StrError { StrError::Try(err) } } /// `NumeralSystem` provides conversions to and from representations in the given system. pub trait NumeralSystem<T> { /** Given a `NumeralSystem` and a number's representation in that system, return the number. Returns `Err` if this function encounters a character not in the system, or if an int to int conversion fails. */ fn decode(&self, rep: &str) -> Result<T, StrError>; /** Given a `NumeralSystem` and a number, return the representation of that number in the system. Returns `Err` if an int to int conversion fails. This will interpret signed integers as if their bits represented their unsigned counterparts. */ fn encode(&self, val: T) -> Result<String, TryFromIntError>; }