// Magical Bitcoin Library // Written in 2020 by // Alekos Filini // // Copyright (c) 2020 Magical Bitcoin // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in all // copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE // SOFTWARE. use std::iter::FromIterator; use crate::descriptor::Error; const INPUT_CHARSET: &str = "0123456789()[],'/*abcdefgh@:$%{}IJKLMNOPQRSTUVWXYZ&+-.;<=>?!^_|~ijklmnopqrstuvwxyzABCDEFGH`#\"\\ "; const CHECKSUM_CHARSET: &str = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"; fn poly_mod(mut c: u64, val: u64) -> u64 { let c0 = c >> 35; c = ((c & 0x7ffffffff) << 5) ^ val; if c0 & 1 > 0 { c ^= 0xf5dee51989 }; if c0 & 2 > 0 { c ^= 0xa9fdca3312 }; if c0 & 4 > 0 { c ^= 0x1bab10e32d }; if c0 & 8 > 0 { c ^= 0x3706b1677a }; if c0 & 16 > 0 { c ^= 0x644d626ffd }; c } pub fn get_checksum(desc: &str) -> Result { let mut c = 1; let mut cls = 0; let mut clscount = 0; for ch in desc.chars() { let pos = INPUT_CHARSET .find(ch) .ok_or(Error::InvalidDescriptorCharacter(ch))? as u64; c = poly_mod(c, pos & 31); cls = cls * 3 + (pos >> 5); clscount += 1; if clscount == 3 { c = poly_mod(c, cls); cls = 0; clscount = 0; } } if clscount > 0 { c = poly_mod(c, cls); } (0..8).for_each(|_| c = poly_mod(c, 0)); c ^= 1; let mut chars = Vec::with_capacity(8); for j in 0..8 { chars.push( CHECKSUM_CHARSET .chars() .nth(((c >> (5 * (7 - j))) & 31) as usize) .unwrap(), ); } Ok(String::from_iter(chars)) }