use bytes::Bytes;
use sha2::{Digest, Sha256};
use crate::v3::Tag;
#[derive(Debug, Default, Copy, Clone, PartialEq, Eq, Hash)]
#[non_exhaustive]
pub enum ChecksumAlgorithm {
None,
#[default]
Sha256,
}
impl ChecksumAlgorithm {
pub fn is_none(self) -> bool {
matches!(self, ChecksumAlgorithm::None)
}
pub fn calculate(self, buffer: &[u8]) -> Checksum {
let mut state = ChecksumState::new(self);
state.update(buffer);
state.finish()
}
}
#[derive(Debug, Clone)]
enum ChecksumState {
None,
Sha256(Sha256),
}
impl ChecksumState {
fn new(algorithm: ChecksumAlgorithm) -> Self {
match algorithm {
ChecksumAlgorithm::None => ChecksumState::None,
ChecksumAlgorithm::Sha256 => ChecksumState::Sha256(Sha256::default()),
}
}
fn update(&mut self, bytes: &[u8]) {
match self {
ChecksumState::None => {
}
ChecksumState::Sha256(sha256) => sha256.update(bytes),
}
}
fn finish(self) -> Checksum {
match self {
ChecksumState::None => Checksum::none(),
ChecksumState::Sha256(sha256) => Checksum::sha256(sha256.finalize().into()),
}
}
}
#[derive(Debug, Clone, PartialEq, Eq, Hash, serde::Serialize, serde::Deserialize)]
pub struct Checksum {
pub tag: Tag,
pub value: Bytes,
}
impl Checksum {
pub const fn new(tag: Tag, value: Bytes) -> Self {
Checksum { tag, value }
}
pub const fn none() -> Self {
Checksum::new(Tag::ChecksumNone, Bytes::new())
}
pub fn sha256(hash: [u8; 32]) -> Self {
Checksum {
tag: Tag::ChecksumSha256,
value: hash.to_vec().into(),
}
}
pub const fn is_none(&self) -> bool {
matches!(self.tag, Tag::ChecksumNone)
}
}