subtle-encoding 0.3.0-alpha1

Encoders and decoders for common data encodings (base64, bech32, hex) which avoid data-dependent branching/table lookups and therefore provide "best effort" constant time. Useful for encoding/decoding secret values such as cryptographic keys.
Documentation 
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//! Macros which provide abort-on-overflow/underflow semantics.
// TODO: replace this with an `AbortOnOverflow<T>` type?

#![allow(dead_code, unused_macros)]

/// Message to abort with on overflow
pub(crate) const OVERFLOW_MSG: &str = "overflow";

/// Checked addition
macro_rules! add {
    ($a:expr, $b:expr) => {
        $a.checked_add($b).expect($crate::macros::OVERFLOW_MSG)
    };
}

/// Checked subtraction
macro_rules! sub {
    ($a:expr, $b:expr) => {
        $a.checked_sub($b).expect($crate::macros::OVERFLOW_MSG)
    };
}

/// Checked multiplication
macro_rules! mul {
    ($a:expr, $b:expr) => {
        $a.checked_mul($b).expect($crate::macros::OVERFLOW_MSG)
    };
}

/// Checked division
macro_rules! div {
    ($a:expr, $b:expr) => {
        $a.checked_div($b).expect($crate::macros::OVERFLOW_MSG)
    };
}

/// Checked right shift
macro_rules! shr {
    ($a:expr, $b:expr) => {
        $a.checked_shr($b).expect($crate::macros::OVERFLOW_MSG)
    };
}

/// Checked left shift
macro_rules! shl {
    ($a:expr, $b:expr) => {
        $a.checked_shl($b).expect($crate::macros::OVERFLOW_MSG)
    };
}