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use std::io;
use crate::crypto::hash::Digest;
use crate::{Error, Result};
use crate::types::HashAlgorithm;
#[derive(Clone)]
struct Hash(HashAlgorithm, botan::HashFunction);
impl Digest for Hash {
fn algo(&self) -> HashAlgorithm {
self.0
}
fn digest_size(&self) -> usize {
self.1.output_length().expect("infallible")
}
fn update(&mut self, data: &[u8]) {
self.1.update(data).expect("infallible");
}
fn digest(&mut self, digest: &mut [u8]) -> Result<()> {
let d = self.1.finish().expect("infallible");
let l = d.len().min(digest.len());
digest[..l].copy_from_slice(&d[..l]);
Ok(())
}
}
impl io::Write for Hash {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.update(buf);
Ok(buf.len())
}
fn flush(&mut self) -> io::Result<()> {
// Do nothing.
Ok(())
}
}
impl HashAlgorithm {
/// Whether Sequoia supports this algorithm.
pub fn is_supported(self) -> bool {
match self {
HashAlgorithm::SHA1 => true,
HashAlgorithm::SHA224 => true,
HashAlgorithm::SHA256 => true,
HashAlgorithm::SHA384 => true,
HashAlgorithm::SHA512 => true,
HashAlgorithm::RipeMD => true,
HashAlgorithm::MD5 => true,
HashAlgorithm::Private(_) => false,
HashAlgorithm::Unknown(_) => false,
}
}
/// Creates a new hash context for this algorithm.
///
/// # Errors
///
/// Fails with `Error::UnsupportedHashAlgorithm` if Sequoia does
/// not support this algorithm. See
/// [`HashAlgorithm::is_supported`].
///
/// [`HashAlgorithm::is_supported`]: HashAlgorithm::is_supported()
pub(crate) fn new_hasher(self) -> Result<Box<dyn Digest>> {
Ok(Box::new(Hash(
self,
botan::HashFunction::new(self.botan_name()?)
.map_err(|_| Error::UnsupportedHashAlgorithm(self))?)))
}
}
impl HashAlgorithm {
/// Returns the name of the algorithm for use with Botan's
/// constructor.
pub(crate) fn botan_name(self) -> Result<&'static str> {
match self {
HashAlgorithm::SHA1 => Ok("SHA-1"),
HashAlgorithm::SHA224 => Ok("SHA-224"),
HashAlgorithm::SHA256 => Ok("SHA-256"),
HashAlgorithm::SHA384 => Ok("SHA-384"),
HashAlgorithm::SHA512 => Ok("SHA-512"),
HashAlgorithm::MD5 => Ok("MD5"),
HashAlgorithm::RipeMD => Ok("RIPEMD-160"),
HashAlgorithm::Private(_) | HashAlgorithm::Unknown(_) =>
Err(Error::UnsupportedHashAlgorithm(self).into()),
}
}
}
#[cfg(tests)]
mod tests {
use super::*;
#[test]
fn is_supported() {
for h in (0..256).iter().map(HashAlgorithm::from) {
assert_eq!(h.is_supported(), h.context().is_ok());
}
}
}
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