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-rw-r--r--src/aes_hash.rs433
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diff --git a/src/aes_hash.rs b/src/aes_hash.rs
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+use crate::convert::*;
+use crate::operations::*;
+use crate::random_state::PI;
+use crate::RandomState;
+use core::hash::Hasher;
+
+/// A `Hasher` for hashing an arbitrary stream of bytes.
+///
+/// Instances of [`AHasher`] represent state that is updated while hashing data.
+///
+/// Each method updates the internal state based on the new data provided. Once
+/// all of the data has been provided, the resulting hash can be obtained by calling
+/// `finish()`
+///
+/// [Clone] is also provided in case you wish to calculate hashes for two different items that
+/// start with the same data.
+///
+#[derive(Debug, Clone)]
+pub struct AHasher {
+ enc: u128,
+ sum: u128,
+ key: u128,
+}
+
+impl AHasher {
+ /// Creates a new hasher keyed to the provided keys.
+ ///
+ /// Normally hashers are created via `AHasher::default()` for fixed keys or `RandomState::new()` for randomly
+ /// generated keys and `RandomState::with_seeds(a,b)` for seeds that are set and can be reused. All of these work at
+ /// map creation time (and hence don't have any overhead on a per-item bais).
+ ///
+ /// This method directly creates the hasher instance and performs no transformation on the provided seeds. This may
+ /// be useful where a HashBuilder is not desired, such as for testing purposes.
+ ///
+ /// # Example
+ ///
+ /// ```
+ /// use std::hash::Hasher;
+ /// use ahash::AHasher;
+ ///
+ /// let mut hasher = AHasher::new_with_keys(1234, 5678);
+ ///
+ /// hasher.write_u32(1989);
+ /// hasher.write_u8(11);
+ /// hasher.write_u8(9);
+ /// hasher.write(b"Huh?");
+ ///
+ /// println!("Hash is {:x}!", hasher.finish());
+ /// ```
+ #[inline]
+ pub(crate) fn new_with_keys(key1: u128, key2: u128) -> Self {
+ let pi: [u128; 2] = PI.convert();
+ let key1 = key1 ^ pi[0];
+ let key2 = key2 ^ pi[1];
+ Self {
+ enc: key1,
+ sum: key2,
+ key: key1 ^ key2,
+ }
+ }
+
+ #[allow(unused)] // False positive
+ pub(crate) fn test_with_keys(key1: u128, key2: u128) -> Self {
+ Self {
+ enc: key1,
+ sum: key2,
+ key: key1 ^ key2,
+ }
+ }
+
+ #[inline]
+ pub(crate) fn from_random_state(rand_state: &RandomState) -> Self {
+ let key1 = [rand_state.k0, rand_state.k1].convert();
+ let key2 = [rand_state.k2, rand_state.k3].convert();
+ Self {
+ enc: key1,
+ sum: key2,
+ key: key1 ^ key2,
+ }
+ }
+
+ #[inline(always)]
+ fn hash_in(&mut self, new_value: u128) {
+ self.enc = aesenc(self.enc, new_value);
+ self.sum = shuffle_and_add(self.sum, new_value);
+ }
+
+ #[inline(always)]
+ fn hash_in_2(&mut self, v1: u128, v2: u128) {
+ self.enc = aesenc(self.enc, v1);
+ self.sum = shuffle_and_add(self.sum, v1);
+ self.enc = aesenc(self.enc, v2);
+ self.sum = shuffle_and_add(self.sum, v2);
+ }
+
+ #[inline]
+ #[cfg(feature = "specialize")]
+ fn short_finish(&self) -> u64 {
+ let combined = aesdec(self.sum, self.enc);
+ let result: [u64; 2] = aesenc(combined, combined).convert();
+ result[0]
+ }
+}
+
+/// Provides [Hasher] methods to hash all of the primitive types.
+///
+/// [Hasher]: core::hash::Hasher
+impl Hasher for AHasher {
+ #[inline]
+ fn write_u8(&mut self, i: u8) {
+ self.write_u64(i as u64);
+ }
+
+ #[inline]
+ fn write_u16(&mut self, i: u16) {
+ self.write_u64(i as u64);
+ }
+
+ #[inline]
+ fn write_u32(&mut self, i: u32) {
+ self.write_u64(i as u64);
+ }
+
+ #[inline]
+ fn write_u128(&mut self, i: u128) {
+ self.hash_in(i);
+ }
+
+ #[inline]
+ #[cfg(any(
+ target_pointer_width = "64",
+ target_pointer_width = "32",
+ target_pointer_width = "16"
+ ))]
+ fn write_usize(&mut self, i: usize) {
+ self.write_u64(i as u64);
+ }
+
+ #[inline]
+ #[cfg(target_pointer_width = "128")]
+ fn write_usize(&mut self, i: usize) {
+ self.write_u128(i as u128);
+ }
+
+ #[inline]
+ fn write_u64(&mut self, i: u64) {
+ self.write_u128(i as u128);
+ }
+
+ #[inline]
+ #[allow(clippy::collapsible_if)]
+ fn write(&mut self, input: &[u8]) {
+ let mut data = input;
+ let length = data.len();
+ add_in_length(&mut self.enc, length as u64);
+
+ //A 'binary search' on sizes reduces the number of comparisons.
+ if data.len() <= 8 {
+ let value = read_small(data);
+ self.hash_in(value.convert());
+ } else {
+ if data.len() > 32 {
+ if data.len() > 64 {
+ let tail = data.read_last_u128x4();
+ let mut current: [u128; 4] = [self.key; 4];
+ current[0] = aesenc(current[0], tail[0]);
+ current[1] = aesenc(current[1], tail[1]);
+ current[2] = aesenc(current[2], tail[2]);
+ current[3] = aesenc(current[3], tail[3]);
+ let mut sum: [u128; 2] = [self.key, self.key];
+ sum[0] = add_by_64s(sum[0].convert(), tail[0].convert()).convert();
+ sum[1] = add_by_64s(sum[1].convert(), tail[1].convert()).convert();
+ sum[0] = shuffle_and_add(sum[0], tail[2]);
+ sum[1] = shuffle_and_add(sum[1], tail[3]);
+ while data.len() > 64 {
+ let (blocks, rest) = data.read_u128x4();
+ current[0] = aesenc(current[0], blocks[0]);
+ current[1] = aesenc(current[1], blocks[1]);
+ current[2] = aesenc(current[2], blocks[2]);
+ current[3] = aesenc(current[3], blocks[3]);
+ sum[0] = shuffle_and_add(sum[0], blocks[0]);
+ sum[1] = shuffle_and_add(sum[1], blocks[1]);
+ sum[0] = shuffle_and_add(sum[0], blocks[2]);
+ sum[1] = shuffle_and_add(sum[1], blocks[3]);
+ data = rest;
+ }
+ self.hash_in_2(aesenc(current[0], current[1]), aesenc(current[2], current[3]));
+ self.hash_in(add_by_64s(sum[0].convert(), sum[1].convert()).convert());
+ } else {
+ //len 33-64
+ let (head, _) = data.read_u128x2();
+ let tail = data.read_last_u128x2();
+ self.hash_in_2(head[0], head[1]);
+ self.hash_in_2(tail[0], tail[1]);
+ }
+ } else {
+ if data.len() > 16 {
+ //len 17-32
+ self.hash_in_2(data.read_u128().0, data.read_last_u128());
+ } else {
+ //len 9-16
+ let value: [u64; 2] = [data.read_u64().0, data.read_last_u64()];
+ self.hash_in(value.convert());
+ }
+ }
+ }
+ }
+ #[inline]
+ fn finish(&self) -> u64 {
+ let combined = aesdec(self.sum, self.enc);
+ let result: [u64; 2] = aesenc(aesenc(combined, self.key), combined).convert();
+ result[0]
+ }
+}
+
+#[cfg(feature = "specialize")]
+pub(crate) struct AHasherU64 {
+ pub(crate) buffer: u64,
+ pub(crate) pad: u64,
+}
+
+/// A specialized hasher for only primitives under 64 bits.
+#[cfg(feature = "specialize")]
+impl Hasher for AHasherU64 {
+ #[inline]
+ fn finish(&self) -> u64 {
+ let rot = (self.pad & 63) as u32;
+ self.buffer.rotate_left(rot)
+ }
+
+ #[inline]
+ fn write(&mut self, _bytes: &[u8]) {
+ unreachable!("Specialized hasher was called with a different type of object")
+ }
+
+ #[inline]
+ fn write_u8(&mut self, i: u8) {
+ self.write_u64(i as u64);
+ }
+
+ #[inline]
+ fn write_u16(&mut self, i: u16) {
+ self.write_u64(i as u64);
+ }
+
+ #[inline]
+ fn write_u32(&mut self, i: u32) {
+ self.write_u64(i as u64);
+ }
+
+ #[inline]
+ fn write_u64(&mut self, i: u64) {
+ self.buffer = folded_multiply(i ^ self.buffer, MULTIPLE);
+ }
+
+ #[inline]
+ fn write_u128(&mut self, _i: u128) {
+ unreachable!("Specialized hasher was called with a different type of object")
+ }
+
+ #[inline]
+ fn write_usize(&mut self, _i: usize) {
+ unreachable!("Specialized hasher was called with a different type of object")
+ }
+}
+
+#[cfg(feature = "specialize")]
+pub(crate) struct AHasherFixed(pub AHasher);
+
+/// A specialized hasher for fixed size primitives larger than 64 bits.
+#[cfg(feature = "specialize")]
+impl Hasher for AHasherFixed {
+ #[inline]
+ fn finish(&self) -> u64 {
+ self.0.short_finish()
+ }
+
+ #[inline]
+ fn write(&mut self, bytes: &[u8]) {
+ self.0.write(bytes)
+ }
+
+ #[inline]
+ fn write_u8(&mut self, i: u8) {
+ self.write_u64(i as u64);
+ }
+
+ #[inline]
+ fn write_u16(&mut self, i: u16) {
+ self.write_u64(i as u64);
+ }
+
+ #[inline]
+ fn write_u32(&mut self, i: u32) {
+ self.write_u64(i as u64);
+ }
+
+ #[inline]
+ fn write_u64(&mut self, i: u64) {
+ self.0.write_u64(i);
+ }
+
+ #[inline]
+ fn write_u128(&mut self, i: u128) {
+ self.0.write_u128(i);
+ }
+
+ #[inline]
+ fn write_usize(&mut self, i: usize) {
+ self.0.write_usize(i);
+ }
+}
+
+#[cfg(feature = "specialize")]
+pub(crate) struct AHasherStr(pub AHasher);
+
+/// A specialized hasher for strings
+/// Note that the other types don't panic because the hash impl for String tacks on an unneeded call. (As does vec)
+#[cfg(feature = "specialize")]
+impl Hasher for AHasherStr {
+ #[inline]
+ fn finish(&self) -> u64 {
+ let result: [u64; 2] = self.0.enc.convert();
+ result[0]
+ }
+
+ #[inline]
+ fn write(&mut self, bytes: &[u8]) {
+ if bytes.len() > 8 {
+ self.0.write(bytes);
+ self.0.enc = aesdec(self.0.sum, self.0.enc);
+ self.0.enc = aesenc(aesenc(self.0.enc, self.0.key), self.0.enc);
+ } else {
+ add_in_length(&mut self.0.enc, bytes.len() as u64);
+
+ let value = read_small(bytes).convert();
+ self.0.sum = shuffle_and_add(self.0.sum, value);
+ self.0.enc = aesdec(self.0.sum, self.0.enc);
+ self.0.enc = aesenc(aesenc(self.0.enc, self.0.key), self.0.enc);
+ }
+ }
+
+ #[inline]
+ fn write_u8(&mut self, _i: u8) {}
+
+ #[inline]
+ fn write_u16(&mut self, _i: u16) {}
+
+ #[inline]
+ fn write_u32(&mut self, _i: u32) {}
+
+ #[inline]
+ fn write_u64(&mut self, _i: u64) {}
+
+ #[inline]
+ fn write_u128(&mut self, _i: u128) {}
+
+ #[inline]
+ fn write_usize(&mut self, _i: usize) {}
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+ use crate::convert::Convert;
+ use crate::operations::aesenc;
+ use crate::RandomState;
+ use std::hash::{BuildHasher, Hasher};
+ #[test]
+ fn test_sanity() {
+ let mut hasher = RandomState::with_seeds(1, 2, 3, 4).build_hasher();
+ hasher.write_u64(0);
+ let h1 = hasher.finish();
+ hasher.write(&[1, 0, 0, 0, 0, 0, 0, 0]);
+ let h2 = hasher.finish();
+ assert_ne!(h1, h2);
+ }
+
+ #[cfg(feature = "compile-time-rng")]
+ #[test]
+ fn test_builder() {
+ use std::collections::HashMap;
+ use std::hash::BuildHasherDefault;
+
+ let mut map = HashMap::<u32, u64, BuildHasherDefault<AHasher>>::default();
+ map.insert(1, 3);
+ }
+
+ #[cfg(feature = "compile-time-rng")]
+ #[test]
+ fn test_default() {
+ let hasher_a = AHasher::default();
+ let a_enc: [u64; 2] = hasher_a.enc.convert();
+ let a_sum: [u64; 2] = hasher_a.sum.convert();
+ assert_ne!(0, a_enc[0]);
+ assert_ne!(0, a_enc[1]);
+ assert_ne!(0, a_sum[0]);
+ assert_ne!(0, a_sum[1]);
+ assert_ne!(a_enc[0], a_enc[1]);
+ assert_ne!(a_sum[0], a_sum[1]);
+ assert_ne!(a_enc[0], a_sum[0]);
+ assert_ne!(a_enc[1], a_sum[1]);
+ let hasher_b = AHasher::default();
+ let b_enc: [u64; 2] = hasher_b.enc.convert();
+ let b_sum: [u64; 2] = hasher_b.sum.convert();
+ assert_eq!(a_enc[0], b_enc[0]);
+ assert_eq!(a_enc[1], b_enc[1]);
+ assert_eq!(a_sum[0], b_sum[0]);
+ assert_eq!(a_sum[1], b_sum[1]);
+ }
+
+ #[test]
+ fn test_hash() {
+ let mut result: [u64; 2] = [0x6c62272e07bb0142, 0x62b821756295c58d];
+ let value: [u64; 2] = [1 << 32, 0xFEDCBA9876543210];
+ result = aesenc(value.convert(), result.convert()).convert();
+ result = aesenc(result.convert(), result.convert()).convert();
+ let mut result2: [u64; 2] = [0x6c62272e07bb0142, 0x62b821756295c58d];
+ let value2: [u64; 2] = [1, 0xFEDCBA9876543210];
+ result2 = aesenc(value2.convert(), result2.convert()).convert();
+ result2 = aesenc(result2.convert(), result.convert()).convert();
+ let result: [u8; 16] = result.convert();
+ let result2: [u8; 16] = result2.convert();
+ assert_ne!(hex::encode(result), hex::encode(result2));
+ }
+
+ #[test]
+ fn test_conversion() {
+ let input: &[u8] = "dddddddd".as_bytes();
+ let bytes: u64 = as_array!(input, 8).convert();
+ assert_eq!(bytes, 0x6464646464646464);
+ }
+}
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