fast32 1.0.3

Base32 and base64 encoding in Rust. Primarily for integer (u64, u128) and UUID identifiers, as well as arbitrary byte arrays.
Documentation 
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use crate::shared::{bits_or_err_u64, DecodeError};

use super::alphabet::{
    WIDTH_1, WIDTH_10, WIDTH_11, WIDTH_12, WIDTH_2, WIDTH_3, WIDTH_4, WIDTH_5, WIDTH_6, WIDTH_7,
    WIDTH_8, WIDTH_9,
};

/// Decode byte array with given decoding, into a u64
///
/// Examples:
/// ```
/// use fast32::base32::CROCKFORD;
/// assert_eq!(CROCKFORD.decode_u128(b"Z").unwrap(), 31);
/// ```
///
/// Returns [`DecodeError`] if input to decode is invalid
#[rustfmt::skip]
pub fn decode_u64(dec: &'static [u8; 256], a: &[u8]) -> Result<u64, DecodeError> {
    let n = match a.len() {
        13 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_12 |
            bits_or_err_u64(dec, a,  1)? << WIDTH_11 |
            bits_or_err_u64(dec, a,  2)? << WIDTH_10 |
            bits_or_err_u64(dec, a,  3)? << WIDTH_9 |
            bits_or_err_u64(dec, a,  4)? << WIDTH_8 |
            bits_or_err_u64(dec, a,  5)? << WIDTH_7 |
            bits_or_err_u64(dec, a,  6)? << WIDTH_6 |
            bits_or_err_u64(dec, a,  7)? << WIDTH_5 |
            bits_or_err_u64(dec, a,  8)? << WIDTH_4 |
            bits_or_err_u64(dec, a,  9)? << WIDTH_3 |
            bits_or_err_u64(dec, a, 10)? << WIDTH_2 |
            bits_or_err_u64(dec, a, 11)? << WIDTH_1 |
            bits_or_err_u64(dec, a, 12)?
        }
        12 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_11 |
            bits_or_err_u64(dec, a,  1)? << WIDTH_10 |
            bits_or_err_u64(dec, a,  2)? << WIDTH_9 |
            bits_or_err_u64(dec, a,  3)? << WIDTH_8 |
            bits_or_err_u64(dec, a,  4)? << WIDTH_7 |
            bits_or_err_u64(dec, a,  5)? << WIDTH_6 |
            bits_or_err_u64(dec, a,  6)? << WIDTH_5 |
            bits_or_err_u64(dec, a,  7)? << WIDTH_4 |
            bits_or_err_u64(dec, a,  8)? << WIDTH_3 |
            bits_or_err_u64(dec, a,  9)? << WIDTH_2 |
            bits_or_err_u64(dec, a, 10)? << WIDTH_1 |
            bits_or_err_u64(dec, a, 11)?
        }
        11 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_10 |
            bits_or_err_u64(dec, a,  1)? << WIDTH_9 |
            bits_or_err_u64(dec, a,  2)? << WIDTH_8 |
            bits_or_err_u64(dec, a,  3)? << WIDTH_7 |
            bits_or_err_u64(dec, a,  4)? << WIDTH_6 |
            bits_or_err_u64(dec, a,  5)? << WIDTH_5 |
            bits_or_err_u64(dec, a,  6)? << WIDTH_4 |
            bits_or_err_u64(dec, a,  7)? << WIDTH_3 |
            bits_or_err_u64(dec, a,  8)? << WIDTH_2 |
            bits_or_err_u64(dec, a,  9)? << WIDTH_1 |
            bits_or_err_u64(dec, a, 10)?
        }
        10 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_9 |
            bits_or_err_u64(dec, a,  1)? << WIDTH_8 |
            bits_or_err_u64(dec, a,  2)? << WIDTH_7 |
            bits_or_err_u64(dec, a,  3)? << WIDTH_6 |
            bits_or_err_u64(dec, a,  4)? << WIDTH_5 |
            bits_or_err_u64(dec, a,  5)? << WIDTH_4 |
            bits_or_err_u64(dec, a,  6)? << WIDTH_3 |
            bits_or_err_u64(dec, a,  7)? << WIDTH_2 |
            bits_or_err_u64(dec, a,  8)? << WIDTH_1 |
            bits_or_err_u64(dec, a,  9)?
        }
        9 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_8 |
            bits_or_err_u64(dec, a,  1)? << WIDTH_7 |
            bits_or_err_u64(dec, a,  2)? << WIDTH_6 |
            bits_or_err_u64(dec, a,  3)? << WIDTH_5 |
            bits_or_err_u64(dec, a,  4)? << WIDTH_4 |
            bits_or_err_u64(dec, a,  5)? << WIDTH_3 |
            bits_or_err_u64(dec, a,  6)? << WIDTH_2 |
            bits_or_err_u64(dec, a,  7)? << WIDTH_1 |
            bits_or_err_u64(dec, a,  8)?
        }
        8 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_7 |
            bits_or_err_u64(dec, a,  1)? << WIDTH_6 |
            bits_or_err_u64(dec, a,  2)? << WIDTH_5 |
            bits_or_err_u64(dec, a,  3)? << WIDTH_4 |
            bits_or_err_u64(dec, a,  4)? << WIDTH_3 |
            bits_or_err_u64(dec, a,  5)? << WIDTH_2 |
            bits_or_err_u64(dec, a,  6)? << WIDTH_1 |
            bits_or_err_u64(dec, a,  7)?
        }
        7 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_6 |
            bits_or_err_u64(dec, a,  1)? << WIDTH_5 |
            bits_or_err_u64(dec, a,  2)? << WIDTH_4 |
            bits_or_err_u64(dec, a,  3)? << WIDTH_3 |
            bits_or_err_u64(dec, a,  4)? << WIDTH_2 |
            bits_or_err_u64(dec, a,  5)? << WIDTH_1 |
            bits_or_err_u64(dec, a,  6)?
        }
        6 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_5 |
            bits_or_err_u64(dec, a,  1)? << WIDTH_4 |
            bits_or_err_u64(dec, a,  2)? << WIDTH_3 |
            bits_or_err_u64(dec, a,  3)? << WIDTH_2 |
            bits_or_err_u64(dec, a,  4)? << WIDTH_1 |
            bits_or_err_u64(dec, a,  5)?
        }
        5 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_4 |
            bits_or_err_u64(dec, a,  1)? << WIDTH_3 |
            bits_or_err_u64(dec, a,  2)? << WIDTH_2 |
            bits_or_err_u64(dec, a,  3)? << WIDTH_1 |
            bits_or_err_u64(dec, a,  4)?
        }
        4 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_3 |
            bits_or_err_u64(dec, a,  1)? << WIDTH_2 |
            bits_or_err_u64(dec, a,  2)? << WIDTH_1 |
            bits_or_err_u64(dec, a,  3)?
        }
        3 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_2 |
            bits_or_err_u64(dec, a,  1)? << WIDTH_1 |
            bits_or_err_u64(dec, a,  2)?
        }
        2 => {
            bits_or_err_u64(dec, a,  0)? << WIDTH_1 |
            bits_or_err_u64(dec, a,  1)?
        }
        1 => {
            bits_or_err_u64(dec, a,  0)?
        }
        0 => 0,
        len @ _ => Err(DecodeError::InvalidLength { length: len })?,
    };
    Ok(n)
}