otp-std 0.2.3

Generating and verifying One-Time Passwords.
Documentation 
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//! Secret encoding and decoding.

use base32::Alphabet;
use miette::Diagnostic;
use thiserror::Error;

use crate::macros::errors;

/// Represents errors that can occur when secret decoding fails.
#[derive(Debug, Error, Diagnostic)]
#[error("failed to decode `{secret}` secret")]
#[diagnostic(code(otp_std::secret::encoding), help("make sure the secret is valid"))]
pub struct Error {
    /// The encoded secret that could not be decoded.
    pub secret: String,
}

impl Error {
    /// Constructs [`Self`].
    pub const fn new(secret: String) -> Self {
        Self { secret }
    }
}

/// The alphabet used for encoding and decoding OTP secrets.
pub const ALPHABET: Alphabet = Alphabet::Rfc4648 { padding: false };

/// Encodes the given secret.
pub fn encode<S: AsRef<[u8]>>(secret: S) -> String {
    base32::encode(ALPHABET, secret.as_ref())
}

errors! {
    Type = Error,
    Hack = $,
    error => new(secret => to_owned),
}

/// Decodes the given secret.
///
/// # Errors
///
/// Returns [`struct@Error`] if the secret could not be decoded.
pub fn decode<S: AsRef<str>>(secret: S) -> Result<Vec<u8>, Error> {
    fn decode_inner(secret: &str) -> Result<Vec<u8>, Error> {
        base32::decode(ALPHABET, secret).ok_or_else(|| error!(secret))
    }

    decode_inner(secret.as_ref())
}