chore: checkpoint before Python removal

vendor/tiny-keccak/src/sha3.rs

@@ -0,0 +1,83 @@
+use crate::{bits_to_rate, keccakf::KeccakF, Hasher, KeccakState};
+
+/// The `SHA3` hash functions defined in [`FIPS-202`].
+///
+/// [`FIPS-202`]: https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf
+///
+/// # Usage
+///
+/// ```toml
+/// [dependencies]
+/// tiny-keccak = { version = "2.0.0", features = ["sha3"] }
+/// ```
+///
+/// # Example
+///
+/// ```
+/// # use tiny_keccak::{Hasher, Sha3};
+/// #
+/// # fn main() {
+/// let input = b"hello world";
+/// let mut output = [0; 32];
+/// let expected = b"\
+///     \x64\x4b\xcc\x7e\x56\x43\x73\x04\x09\x99\xaa\xc8\x9e\x76\x22\xf3\
+///     \xca\x71\xfb\xa1\xd9\x72\xfd\x94\xa3\x1c\x3b\xfb\xf2\x4e\x39\x38\
+/// ";
+/// let mut sha3 = Sha3::v256();
+/// sha3.update(input);
+/// sha3.finalize(&mut output);
+/// assert_eq!(expected, &output);
+/// # }
+/// ```
+#[derive(Clone)]
+pub struct Sha3 {
+    state: KeccakState<KeccakF>,
+}
+
+impl Sha3 {
+    const DELIM: u8 = 0x06;
+
+    /// Creates  new [`Sha3`] hasher with a security level of 224 bits.
+    ///
+    /// [`Sha3`]: struct.Sha3.html
+    pub fn v224() -> Sha3 {
+        Sha3::new(224)
+    }
+
+    /// Creates  new [`Sha3`] hasher with a security level of 256 bits.
+    ///
+    /// [`Sha3`]: struct.Sha3.html
+    pub fn v256() -> Sha3 {
+        Sha3::new(256)
+    }
+
+    /// Creates  new [`Sha3`] hasher with a security level of 384 bits.
+    ///
+    /// [`Sha3`]: struct.Sha3.html
+    pub fn v384() -> Sha3 {
+        Sha3::new(384)
+    }
+
+    /// Creates  new [`Sha3`] hasher with a security level of 512 bits.
+    ///
+    /// [`Sha3`]: struct.Sha3.html
+    pub fn v512() -> Sha3 {
+        Sha3::new(512)
+    }
+
+    fn new(bits: usize) -> Sha3 {
+        Sha3 {
+            state: KeccakState::new(bits_to_rate(bits), Self::DELIM),
+        }
+    }
+}
+
+impl Hasher for Sha3 {
+    fn update(&mut self, input: &[u8]) {
+        self.state.update(input);
+    }
+
+    fn finalize(self, output: &mut [u8]) {
+        self.state.finalize(output);
+    }
+}