forked from mrhooray/crc-rs
/
crc64.rs
69 lines (59 loc) · 1.76 KB
/
crc64.rs
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use super::{Algorithm, Crc, Digest};
use crate::table::crc64_table;
impl Crc<u64> {
pub const fn new(algorithm: &'static Algorithm<u64>) -> Self {
let table = crc64_table(algorithm.poly, algorithm.refin);
Self { algorithm, table }
}
pub const fn checksum(&self, bytes: &[u8]) -> u64 {
let mut crc = self.init();
crc = self.update(crc, bytes);
self.finalize(crc)
}
const fn init(&self) -> u64 {
if self.algorithm.refin {
self.algorithm.init.reverse_bits()
} else {
self.algorithm.init
}
}
const fn table_entry(&self, index: u64) -> u64 {
self.table[(index & 0xFF) as usize]
}
const fn update(&self, mut crc: u64, bytes: &[u8]) -> u64 {
let mut i = 0;
if self.algorithm.refin {
while i < bytes.len() {
crc = self.table_entry(crc ^ bytes[i] as u64) ^ (crc >> 8);
i += 1;
}
} else {
while i < bytes.len() {
crc = self.table_entry(bytes[i] as u64 ^ (crc >> 56)) ^ (crc << 8);
i += 1;
}
}
crc
}
const fn finalize(&self, mut crc: u64) -> u64 {
if self.algorithm.refin ^ self.algorithm.refout {
crc = crc.reverse_bits();
}
crc ^ self.algorithm.xorout
}
pub const fn digest(&self) -> Digest<u64> {
Digest::new(self)
}
}
impl<'a> Digest<'a, u64> {
const fn new(crc: &'a Crc<u64>) -> Self {
let value = crc.init();
Digest { crc, value }
}
pub fn update(&mut self, bytes: &[u8]) {
self.value = self.crc.update(self.value, bytes);
}
pub const fn finalize(self) -> u64 {
self.crc.finalize(self.value)
}
}