fraction 0.17.0

//! Crate error types
//!
//! Contains error types utilised by other modules within the crate

use std::error::Error;
use std::fmt;
use std::io;

/// Errors returned while parsing numeric strings in this crate.
///
/// Consumers should include a wildcard arm when matching this error so that
/// additions to the error set remain source-compatible.
///
/// ```
/// use fraction::error::ParseError;
///
/// fn error_label(error: ParseError) -> &'static str {
///     match error {
///         ParseError::ParseIntError => "bad digits",
///         ParseError::UnsupportedBase => "bad radix",
///         _ => "other",
///     }
/// }
///
/// assert_eq!(error_label(ParseError::ParseIntError), "bad digits");
/// assert_eq!(error_label(ParseError::UnsupportedBase), "bad radix");
/// ```
#[derive(Debug, Clone, Eq, PartialEq)]
#[non_exhaustive]
pub enum ParseError {
    /// Not enough capacity in underlying integer to perform a math operation
    OverflowError,

    /// A numeric component or parser-combined value could not be parsed or
    /// represented by the selected integer type.
    ParseIntError,

    /// The requested base is outside the range supported by the parser.
    /// [`GenericFraction`](crate::GenericFraction)'s `from_str_radix` and
    /// direct `DynaInt` parsing accept bases 2 through 36, while
    /// `GenericDecimal` supports base 10 only. Backing types may have their
    /// own additional requirements for an in-range base.
    UnsupportedBase,

    /// A finite-ratio parser received a zero denominator.
    ///
    /// [`GenericFraction`](crate::GenericFraction)'s `from_str_radix` reports
    /// this error. Ordinary and Unicode fraction parsing instead map a zero
    /// denominator to infinity or NaN.
    ZeroDenominator,
}

unsafe impl Send for ParseError {}
unsafe impl Sync for ParseError {}

impl fmt::Display for ParseError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            ParseError::OverflowError => write!(f, "Overflow"),
            ParseError::ParseIntError => write!(f, "Could not parse integer"),
            ParseError::UnsupportedBase => write!(f, "Unsupported base"),
            ParseError::ZeroDenominator => write!(f, "Zero denominator"),
        }
    }
}

impl Error for ParseError {}

/// Could not perform division, or fill in the resulting buffer
#[derive(Debug)]
pub enum DivisionError {
    /// Trying to divide something by Zero
    DivisionByZero,

    /// Incapsulates [fmt::Error]
    FmtError(fmt::Error),

    /// Incapsulates [io::Error]
    IoError(io::Error),

    /// Errors external to the division algorithm still may be passed
    /// through the co-routines wrapped up with this constructor
    ExternalError(Box<dyn Error + Send + Sync>),
}

unsafe impl Sync for DivisionError {}
unsafe impl Send for DivisionError {}

impl fmt::Display for DivisionError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            DivisionError::DivisionByZero => write!(f, "Division by zero"),

            DivisionError::FmtError(e) => write!(f, "Fmt error: {}", e),
            DivisionError::IoError(e) => write!(f, "IO error: {}", e),

            DivisionError::ExternalError(e) => write!(f, "External error: {}", e),
        }
    }
}

impl Error for DivisionError {}

impl From<io::Error> for DivisionError {
    fn from(error: io::Error) -> DivisionError {
        DivisionError::IoError(error)
    }
}

impl From<fmt::Error> for DivisionError {
    fn from(error: fmt::Error) -> DivisionError {
        DivisionError::FmtError(error)
    }
}