127 lines
3.2 KiB
Rust
127 lines
3.2 KiB
Rust
use super::DIGEST_SIZE;
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use crate::{
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ByteReader, ByteWriter, Deserializable, DeserializationError, Digest, Felt, Serializable,
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StarkField, String, ZERO,
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};
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use core::ops::Deref;
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// DIGEST TRAIT IMPLEMENTATIONS
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// ================================================================================================
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#[derive(Debug, Copy, Clone, Eq, PartialEq)]
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pub struct RpoDigest256([Felt; DIGEST_SIZE]);
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impl RpoDigest256 {
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pub fn new(value: [Felt; DIGEST_SIZE]) -> Self {
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Self(value)
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}
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pub fn as_elements(&self) -> &[Felt] {
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self.as_ref()
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}
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pub fn digests_as_elements<'a, I>(digests: I) -> impl Iterator<Item = &'a Felt>
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where
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I: Iterator<Item = &'a Self>,
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{
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digests.flat_map(|d| d.0.iter())
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}
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}
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impl Digest for RpoDigest256 {
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fn as_bytes(&self) -> [u8; 32] {
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let mut result = [0; 32];
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result[..8].copy_from_slice(&self.0[0].as_int().to_le_bytes());
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result[8..16].copy_from_slice(&self.0[1].as_int().to_le_bytes());
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result[16..24].copy_from_slice(&self.0[2].as_int().to_le_bytes());
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result[24..].copy_from_slice(&self.0[3].as_int().to_le_bytes());
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result
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}
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}
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impl Default for RpoDigest256 {
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fn default() -> Self {
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RpoDigest256([Felt::default(); DIGEST_SIZE])
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}
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}
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impl Serializable for RpoDigest256 {
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fn write_into<W: ByteWriter>(&self, target: &mut W) {
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target.write_u8_slice(&self.as_bytes());
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}
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}
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impl Deserializable for RpoDigest256 {
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fn read_from<R: ByteReader>(source: &mut R) -> Result<Self, DeserializationError> {
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let mut inner: [Felt; DIGEST_SIZE] = [ZERO; DIGEST_SIZE];
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for inner in inner.iter_mut() {
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let e = source.read_u64()?;
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if e >= Felt::MODULUS {
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return Err(DeserializationError::InvalidValue(String::from(
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"Value not in the appropriate range",
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)));
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}
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*inner = Felt::new(e);
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}
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Ok(Self(inner))
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}
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}
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impl From<[Felt; DIGEST_SIZE]> for RpoDigest256 {
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fn from(value: [Felt; DIGEST_SIZE]) -> Self {
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Self(value)
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}
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}
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impl From<RpoDigest256> for [Felt; DIGEST_SIZE] {
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fn from(value: RpoDigest256) -> Self {
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value.0
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}
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}
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impl From<RpoDigest256> for [u8; 32] {
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fn from(value: RpoDigest256) -> Self {
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value.as_bytes()
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}
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}
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impl Deref for RpoDigest256 {
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type Target = [Felt; DIGEST_SIZE];
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fn deref(&self) -> &Self::Target {
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&self.0
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}
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}
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// TESTS
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// ================================================================================================
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#[cfg(test)]
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mod tests {
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use super::RpoDigest256;
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use crate::{Deserializable, Felt, Serializable, SliceReader};
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use rand_utils::rand_value;
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#[test]
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fn digest_serialization() {
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let e1 = Felt::new(rand_value());
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let e2 = Felt::new(rand_value());
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let e3 = Felt::new(rand_value());
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let e4 = Felt::new(rand_value());
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let d1 = RpoDigest256([e1, e2, e3, e4]);
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let mut bytes = vec![];
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d1.write_into(&mut bytes);
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assert_eq!(32, bytes.len());
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let mut reader = SliceReader::new(&bytes);
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let d2 = RpoDigest256::read_from(&mut reader).unwrap();
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assert_eq!(d1, d2);
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}
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}
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