cuprate-hinto-janai/helper/src/map.rs

//! Mapping of data types.
//!
//! This module provides functions solely for mapping data types into others, mostly similar ones.
//!
//! `#[no_std]` compatible.

//---------------------------------------------------------------------------------------------------- Use

//---------------------------------------------------------------------------------------------------- `(u64, u64) <-> u128`
/// Split a [`u128`] value into 2 64-bit values.
///
/// The tuple returned is `(low, high)` where `low` is the least significant
/// 64-bits of `number`, and `high` is the most significant.
///
/// Note that the output of this function are `u64` representations of _bits_, not numerical values.
///
/// See [`combine_low_high_bits_to_u128`] for the inverse function.
///
/// ```rust
/// # use cuprate_helper::map::*;
/// let value = u128::MAX - 1;
/// let low = u64::MAX - 1;
/// let high = u64::MAX;
///
/// assert_eq!(split_u128_into_low_high_bits(value), (low, high));
/// ```
#[inline]
pub const fn split_u128_into_low_high_bits(value: u128) -> (u64, u64) {
    (value as u64, (value >> 64) as u64)
}

/// Combine 2 64-bit values into a single [`u128`] value.
///
/// The inputs:
/// - `low_bits` are the _least_ significant 64-bits of `cumulative_difficulty`
/// - `high_bits` are the _most_ significant 64-bits of `cumulative_difficulty`
///
/// Note that `low_bits` & `high_bits` should be `u64` representation of _bits_, not numerical values.
///
/// See [`split_u128_into_low_high_bits`] for the inverse function.
///
/// ```rust
/// # use cuprate_helper::map::*;
/// let value = u128::MAX - 1;
/// let low = u64::MAX - 1;
/// let high = u64::MAX;
///
/// assert_eq!(combine_low_high_bits_to_u128(low, high), value);
/// ```
#[inline]
pub const fn combine_low_high_bits_to_u128(low_bits: u64, high_bits: u64) -> u128 {
    let res = (high_bits as u128) << 64;
    res | (low_bits as u128)
}

//---------------------------------------------------------------------------------------------------- Tests
#[cfg(test)]
mod test {}