use core::mem::size_of;
use zerocopy::{AsBytes, FromBytes};
/// A sha256 hash digest. The standard hash in the scuttleverse.
#[derive(AsBytes, FromBytes, PartialEq, Debug)]
#[repr(C)]
pub struct Hash(pub [u8; 32]);
impl Hash {
/// The size in bytes of the Hash type ( == 32).
pub const SIZE: usize = size_of::<Self>();
/// Deserialize from byte representation.
/// Returns `None` if the slice length isn't 32.
/// Note that this doesn't hash the provided byte slice,
/// use the [`hash`] function for that.
pub fn from_slice(s: &[u8]) -> Option<Self> {
if s.len() == Self::SIZE {
let mut out = Self([0; Self::SIZE]);
out.0.copy_from_slice(s);
Some(out)
} else {
None
}
}
/// Deserialize from base-64 string representation.
/// Ignores optional leading '%' or '&' sigil and '.sha256' suffix.
///
/// # Example
/// ```rust
/// let s = "%4hUgS4j0TwKdsZzOV/tfqiPtqoLw2qYg/Wl9Xy8FPEU=.sha256";
/// let h = ssb_crypto::Hash::from_base64(s).unwrap();
/// ```
#[cfg(feature = "b64")]
pub fn from_base64(mut s: &str) -> Option<Self> {
let mut buf = [0; Self::SIZE];
if s.starts_with('%') || s.starts_with('&') {
s = &s[1..];
}
if crate::b64::decode(s, &mut buf, Some(".sha256")) {
Some(Self(buf))
} else {
None
}
}
/// Does not include ".sha256" suffix or a sigil prefix.
///
/// # Example
/// ```rust
/// let s = "4hUgS4j0TwKdsZzOV/tfqiPtqoLw2qYg/Wl9Xy8FPEU=";
/// let h = ssb_crypto::Hash::from_base64(s).unwrap();
/// assert_eq!(h.as_base64(), s);
/// ```
#[cfg(feature = "alloc")]
pub fn as_base64(&self) -> alloc::string::String {
base64::encode_config(&self.0[..], base64::STANDARD)
}
}
#[cfg(all(feature = "dalek", not(feature = "force_sodium")))]
pub use crate::dalek::hash::hash;
#[cfg(all(
feature = "sodium",
any(feature = "force_sodium", not(feature = "dalek"))
))]
pub use crate::sodium::hash::hash;