feat: add a join module to join arrays into larger integers #79

This commit is contained in:
Christoph J. Scherr 2024-05-13 14:56:37 +02:00
parent 0a6072c478
commit 2e38597a7c
2 changed files with 45 additions and 0 deletions

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@ -0,0 +1,44 @@
//! # Join bits and bytes into numbers
//!
//! Sometimes you have a `[u8]` that is the representation of a larger unsigned integer, such as
//! [u128]. This module helps you join them together.
use anyhow::anyhow;
use libpt_log::trace;
/// Join a [Vec] of [u8]s into an unsigned integer
///
/// Say you have the array `[0b00000110, 0b10110101]` and want to use it as a [u32].
/// This function sets it together to a integer type of your choosing:
/// 1717 (binary: `00000000 00000000 00000110 10110101`).
///
/// If the array is not long enough, the number will be padded with null bytes.
///
/// # Examples
///
/// ```
/// # use libpt_bintols::join::*;
///
/// let x: [u8; 2] = [0b00000110, 0b10110101];
///
/// assert_eq!(array_to_unsigned::<u32>(&x).unwrap(), 1717);
/// ```
pub fn array_to_unsigned<T>(parts: &[u8]) -> anyhow::Result<T>
where
u128: std::convert::From<T>,
T: std::str::FromStr,
<T as std::str::FromStr>::Err: std::fmt::Debug,
{
trace!("amount of parts: {}", parts.len());
if parts.len() > (u128::BITS / 8) as usize {
return Err(anyhow!(
"the list is too long to fit into the specified integer type: {}",
std::any::type_name::<T>()
));
}
let mut ri: u128 = 0;
for (i, e) in parts.iter().rev().enumerate() {
ri += (*e as u128) * 256u128.pow(i as u32);
}
Ok(ri.to_string().parse().unwrap())
}

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@ -26,3 +26,4 @@ pub const YOBI: u128 = 2u128.pow(80);
pub mod datalayout;
pub mod display;
pub mod split;
pub mod join;