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