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
use crate::shared::{bits_or_err_u128, DecodeError};

use super::alphabet::{
    WIDTH_1, WIDTH_10, WIDTH_11, WIDTH_12, WIDTH_13, WIDTH_14, WIDTH_15, WIDTH_16, WIDTH_17,
    WIDTH_18, WIDTH_19, WIDTH_2, WIDTH_20, WIDTH_21, WIDTH_3, WIDTH_4, WIDTH_5, WIDTH_6, WIDTH_7,
    WIDTH_8, WIDTH_9,
};

/// Decode byte array with given decoding, into a u128
///
/// Examples:
/// ```
/// use fast32::base64::RFC4648_NOPAD;
/// assert_eq!(RFC4648_NOPAD.decode_u128(b"Bv").unwrap(), 111);
/// ```
///
/// Returns [`DecodeError`] if input to decode is invalid
#[rustfmt::skip]
pub fn decode_u128(dec: &'static [u8; 256], a: &[u8]) -> Result<u128, DecodeError> {
    let n = match a.len() {
        22 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_21 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_20 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_19 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_18 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_17 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_16 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_15 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_14 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_13 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_12 |
            bits_or_err_u128(dec, a, 10)? << WIDTH_11 |
            bits_or_err_u128(dec, a, 11)? << WIDTH_10 |
            bits_or_err_u128(dec, a, 12)? << WIDTH_9 |
            bits_or_err_u128(dec, a, 13)? << WIDTH_8 |
            bits_or_err_u128(dec, a, 14)? << WIDTH_7 |
            bits_or_err_u128(dec, a, 15)? << WIDTH_6 |
            bits_or_err_u128(dec, a, 16)? << WIDTH_5 |
            bits_or_err_u128(dec, a, 17)? << WIDTH_4 |
            bits_or_err_u128(dec, a, 18)? << WIDTH_3 |
            bits_or_err_u128(dec, a, 19)? << WIDTH_2 |
            bits_or_err_u128(dec, a, 20)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 21)?
        }
        21 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_20 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_19 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_18 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_17 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_16 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_15 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_14 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_13 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_12 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_11 |
            bits_or_err_u128(dec, a, 10)? << WIDTH_10 |
            bits_or_err_u128(dec, a, 11)? << WIDTH_9 |
            bits_or_err_u128(dec, a, 12)? << WIDTH_8 |
            bits_or_err_u128(dec, a, 13)? << WIDTH_7 |
            bits_or_err_u128(dec, a, 14)? << WIDTH_6 |
            bits_or_err_u128(dec, a, 15)? << WIDTH_5 |
            bits_or_err_u128(dec, a, 16)? << WIDTH_4 |
            bits_or_err_u128(dec, a, 17)? << WIDTH_3 |
            bits_or_err_u128(dec, a, 18)? << WIDTH_2 |
            bits_or_err_u128(dec, a, 19)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 20)?
        }
        20 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_19 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_18 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_17 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_16 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_15 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_14 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_13 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_12 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_11 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_10 |
            bits_or_err_u128(dec, a, 10)? << WIDTH_9 |
            bits_or_err_u128(dec, a, 11)? << WIDTH_8 |
            bits_or_err_u128(dec, a, 12)? << WIDTH_7 |
            bits_or_err_u128(dec, a, 13)? << WIDTH_6 |
            bits_or_err_u128(dec, a, 14)? << WIDTH_5 |
            bits_or_err_u128(dec, a, 15)? << WIDTH_4 |
            bits_or_err_u128(dec, a, 16)? << WIDTH_3 |
            bits_or_err_u128(dec, a, 17)? << WIDTH_2 |
            bits_or_err_u128(dec, a, 18)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 19)?
        }
        19 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_18 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_17 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_16 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_15 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_14 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_13 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_12 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_11 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_10 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_9 |
            bits_or_err_u128(dec, a, 10)? << WIDTH_8 |
            bits_or_err_u128(dec, a, 11)? << WIDTH_7 |
            bits_or_err_u128(dec, a, 12)? << WIDTH_6 |
            bits_or_err_u128(dec, a, 13)? << WIDTH_5 |
            bits_or_err_u128(dec, a, 14)? << WIDTH_4 |
            bits_or_err_u128(dec, a, 15)? << WIDTH_3 |
            bits_or_err_u128(dec, a, 16)? << WIDTH_2 |
            bits_or_err_u128(dec, a, 17)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 18)?
        }
        18 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_17 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_16 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_15 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_14 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_13 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_12 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_11 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_10 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_9 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_8 |
            bits_or_err_u128(dec, a, 10)? << WIDTH_7 |
            bits_or_err_u128(dec, a, 11)? << WIDTH_6 |
            bits_or_err_u128(dec, a, 12)? << WIDTH_5 |
            bits_or_err_u128(dec, a, 13)? << WIDTH_4 |
            bits_or_err_u128(dec, a, 14)? << WIDTH_3 |
            bits_or_err_u128(dec, a, 15)? << WIDTH_2 |
            bits_or_err_u128(dec, a, 16)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 17)?
        }
        17 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_16 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_15 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_14 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_13 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_12 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_11 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_10 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_9 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_8 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_7 |
            bits_or_err_u128(dec, a, 10)? << WIDTH_6 |
            bits_or_err_u128(dec, a, 11)? << WIDTH_5 |
            bits_or_err_u128(dec, a, 12)? << WIDTH_4 |
            bits_or_err_u128(dec, a, 13)? << WIDTH_3 |
            bits_or_err_u128(dec, a, 14)? << WIDTH_2 |
            bits_or_err_u128(dec, a, 15)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 16)?
        }
        16 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_15 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_14 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_13 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_12 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_11 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_10 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_9 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_8 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_7 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_6 |
            bits_or_err_u128(dec, a, 10)? << WIDTH_5 |
            bits_or_err_u128(dec, a, 11)? << WIDTH_4 |
            bits_or_err_u128(dec, a, 12)? << WIDTH_3 |
            bits_or_err_u128(dec, a, 13)? << WIDTH_2 |
            bits_or_err_u128(dec, a, 14)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 15)?
        }
        15 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_14 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_13 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_12 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_11 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_10 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_9 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_8 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_7 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_6 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_5 |
            bits_or_err_u128(dec, a, 10)? << WIDTH_4 |
            bits_or_err_u128(dec, a, 11)? << WIDTH_3 |
            bits_or_err_u128(dec, a, 12)? << WIDTH_2 |
            bits_or_err_u128(dec, a, 13)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 14)?
        }
        14 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_13 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_12 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_11 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_10 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_9 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_8 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_7 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_6 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_5 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_4 |
            bits_or_err_u128(dec, a, 10)? << WIDTH_3 |
            bits_or_err_u128(dec, a, 11)? << WIDTH_2 |
            bits_or_err_u128(dec, a, 12)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 13)?
        }
        13 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_12 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_11 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_10 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_9 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_8 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_7 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_6 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_5 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_4 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_3 |
            bits_or_err_u128(dec, a, 10)? << WIDTH_2 |
            bits_or_err_u128(dec, a, 11)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 12)?
        }
        12 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_11 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_10 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_9 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_8 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_7 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_6 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_5 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_4 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_3 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_2 |
            bits_or_err_u128(dec, a, 10)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 11)?
        }
        11 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_10 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_9 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_8 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_7 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_6 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_5 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_4 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_3 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_2 |
            bits_or_err_u128(dec, a,  9)? << WIDTH_1 |
            bits_or_err_u128(dec, a, 10)?
        }
        10 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_9 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_8 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_7 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_6 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_5 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_4 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_3 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_2 |
            bits_or_err_u128(dec, a,  8)? << WIDTH_1 |
            bits_or_err_u128(dec, a,  9)?
        }
        9 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_8 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_7 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_6 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_5 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_4 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_3 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_2 |
            bits_or_err_u128(dec, a,  7)? << WIDTH_1 |
            bits_or_err_u128(dec, a,  8)?
        }
        8 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_7 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_6 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_5 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_4 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_3 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_2 |
            bits_or_err_u128(dec, a,  6)? << WIDTH_1 |
            bits_or_err_u128(dec, a,  7)?
        }
        7 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_6 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_5 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_4 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_3 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_2 |
            bits_or_err_u128(dec, a,  5)? << WIDTH_1 |
            bits_or_err_u128(dec, a,  6)?
        }
        6 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_5 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_4 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_3 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_2 |
            bits_or_err_u128(dec, a,  4)? << WIDTH_1 |
            bits_or_err_u128(dec, a,  5)?
        }
       5 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_4 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_3 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_2 |
            bits_or_err_u128(dec, a,  3)? << WIDTH_1 |
            bits_or_err_u128(dec, a,  4)?
        }
        4 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_3 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_2 |
            bits_or_err_u128(dec, a,  2)? << WIDTH_1 |
            bits_or_err_u128(dec, a,  3)?
        }
        3 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_2 |
            bits_or_err_u128(dec, a,  1)? << WIDTH_1 |
            bits_or_err_u128(dec, a,  2)?
        }
        2 => {
            bits_or_err_u128(dec, a,  0)? << WIDTH_1 |
            bits_or_err_u128(dec, a,  1)?
        }
        1 => {
            bits_or_err_u128(dec, a,  0)?
        }
        0 => 0,
        len @ _ => Err(DecodeError::InvalidLength { length: len })?,
    };
    Ok(n)
}