Move EpochRewardsHasher to solana-sdk

runtime/Cargo.toml

@@ -47,7 +47,6 @@ regex = { workspace = true }
 serde = { workspace = true, features = ["rc"] }
 serde_derive = { workspace = true }
 serde_json = { workspace = true }
-siphasher = { workspace = true }
 solana-accounts-db = { workspace = true }
 solana-address-lookup-table-program = { workspace = true }
 solana-bpf-loader-program = { workspace = true }

runtime/src/epoch_rewards_hasher.rs

@@ -1,45 +1,8 @@
 use {
     crate::bank::StakeRewards,
-    siphasher::sip::SipHasher13,
-    solana_sdk::{hash::Hash, pubkey::Pubkey},
-    std::hash::Hasher,
+    solana_sdk::{epoch_rewards_hasher::EpochRewardsHasher, hash::Hash},
 };
 
-#[derive(Debug, Clone)]
-pub(crate) struct EpochRewardsHasher {
-    hasher: SipHasher13,
-    partitions: usize,
-}
-
-impl EpochRewardsHasher {
-    /// Use SipHasher13 keyed on the `seed` for calculating epoch reward partition
-    pub(crate) fn new(partitions: usize, seed: &Hash) -> Self {
-        let mut hasher = SipHasher13::new();
-        hasher.write(seed.as_ref());
-        Self { hasher, partitions }
-    }
-
-    /// Return partition index (0..partitions) by hashing `address` with the `hasher`
-    pub(crate) fn hash_address_to_partition(self, address: &Pubkey) -> usize {
-        let Self {
-            mut hasher,
-            partitions,
-        } = self;
-        hasher.write(address.as_ref());
-        let hash64 = hasher.finish();
-
-        hash_to_partition(hash64, partitions)
-    }
-}
-
-/// Compute the partition index by modulo the address hash to number of partitions w.o bias.
-/// (rand_int * DESIRED_RANGE_MAX) / (RAND_MAX + 1)
-fn hash_to_partition(hash: u64, partitions: usize) -> usize {
-    ((partitions as u128)
-        .saturating_mul(u128::from(hash))
-        .saturating_div(u128::from(u64::MAX).saturating_add(1))) as usize
-}
-
 pub(crate) fn hash_rewards_into_partitions(
     stake_rewards: StakeRewards,
     parent_blockhash: &Hash,
@@ -62,148 +25,7 @@ pub(crate) fn hash_rewards_into_partitions(
 
 #[cfg(test)]
 mod tests {
-    use {
-        super::*,
-        solana_accounts_db::stake_rewards::StakeReward,
-        std::{collections::HashMap, ops::RangeInclusive},
-    };
-
-    #[test]
-    fn test_get_equal_partition_range() {
-        // show how 2 equal partition ranges are 0..=(max/2), (max/2+1)..=max
-        // the inclusive is tricky to think about
-        let range = get_equal_partition_range(0, 2);
-        assert_eq!(*range.start(), 0);
-        assert_eq!(*range.end(), u64::MAX / 2);
-        let range = get_equal_partition_range(1, 2);
-        assert_eq!(*range.start(), u64::MAX / 2 + 1);
-        assert_eq!(*range.end(), u64::MAX);
-    }
-
-    #[test]
-    fn test_hash_to_partitions() {
-        let partitions = 16;
-        assert_eq!(hash_to_partition(0, partitions), 0);
-        assert_eq!(hash_to_partition(u64::MAX / 16, partitions), 0);
-        assert_eq!(hash_to_partition(u64::MAX / 16 + 1, partitions), 1);
-        assert_eq!(hash_to_partition(u64::MAX / 16 * 2, partitions), 1);
-        assert_eq!(hash_to_partition(u64::MAX / 16 * 2 + 1, partitions), 1);
-        assert_eq!(hash_to_partition(u64::MAX - 1, partitions), partitions - 1);
-        assert_eq!(hash_to_partition(u64::MAX, partitions), partitions - 1);
-    }
-
-    fn test_partitions(partition: usize, partitions: usize) {
-        let partition = partition.min(partitions - 1);
-        let range = get_equal_partition_range(partition, partitions);
-        // beginning and end of this partition
-        assert_eq!(hash_to_partition(*range.start(), partitions), partition);
-        assert_eq!(hash_to_partition(*range.end(), partitions), partition);
-        if partition < partitions - 1 {
-            // first index in next partition
-            assert_eq!(
-                hash_to_partition(*range.end() + 1, partitions),
-                partition + 1
-            );
-        } else {
-            assert_eq!(*range.end(), u64::MAX);
-        }
-        if partition > 0 {
-            // last index in previous partition
-            assert_eq!(
-                hash_to_partition(*range.start() - 1, partitions),
-                partition - 1
-            );
-        } else {
-            assert_eq!(*range.start(), 0);
-        }
-    }
-
-    #[test]
-    fn test_hash_to_partitions_equal_ranges() {
-        for partitions in [2, 4, 8, 16, 4096] {
-            assert_eq!(hash_to_partition(0, partitions), 0);
-            for partition in [0, 1, 2, partitions - 1] {
-                test_partitions(partition, partitions);
-            }
-
-            let range = get_equal_partition_range(0, partitions);
-            for partition in 1..partitions {
-                let this_range = get_equal_partition_range(partition, partitions);
-                assert_eq!(
-                    this_range.end() - this_range.start(),
-                    range.end() - range.start()
-                );
-            }
-        }
-        // verify non-evenly divisible partitions (partitions will be different sizes by at most 1 from any other partition)
-        for partitions in [3, 19, 1019, 4095] {
-            for partition in [0, 1, 2, partitions - 1] {
-                test_partitions(partition, partitions);
-            }
-            let expected_len_of_partition =
-                ((u128::from(u64::MAX) + 1) / partitions as u128) as u64;
-            for partition in 0..partitions {
-                let this_range = get_equal_partition_range(partition, partitions);
-                let len = this_range.end() - this_range.start();
-                // size is same or 1 less
-                assert!(
-                    len == expected_len_of_partition || len + 1 == expected_len_of_partition,
-                    "{}, {}, {}, {}",
-                    expected_len_of_partition,
-                    len,
-                    partition,
-                    partitions
-                );
-            }
-        }
-    }
-
-    /// return start and end_inclusive of `partition` indexes out of from u64::MAX+1 elements in equal `partitions`
-    /// These will be equal as long as (u64::MAX + 1) divides by `partitions` evenly
-    fn get_equal_partition_range(partition: usize, partitions: usize) -> RangeInclusive<u64> {
-        let max_inclusive = u128::from(u64::MAX);
-        let max_plus_1 = max_inclusive + 1;
-        let partition = partition as u128;
-        let partitions = partitions as u128;
-        let mut start = max_plus_1 * partition / partitions;
-        if partition > 0 && start * partitions / max_plus_1 == partition - 1 {
-            // partitions don't evenly divide and the start of this partition needs to be 1 greater
-            start += 1;
-        }
-
-        let mut end_inclusive = start + max_plus_1 / partitions - 1;
-        if partition < partitions.saturating_sub(1) {
-            let next = end_inclusive + 1;
-            if next * partitions / max_plus_1 == partition {
-                // this partition is far enough into partitions such that the len of this partition is 1 larger than expected
-                end_inclusive += 1;
-            }
-        } else {
-            end_inclusive = max_inclusive;
-        }
-        RangeInclusive::new(start as u64, end_inclusive as u64)
-    }
-
-    /// Make sure that each time hash_address_to_partition is called, it uses the initial seed state and that clone correctly copies the initial hasher state.
-    #[test]
-    fn test_hasher_copy() {
-        let seed = Hash::new_unique();
-        let partitions = 10;
-        let hasher = EpochRewardsHasher::new(partitions, &seed);
-
-        let pk = Pubkey::new_unique();
-
-        let b1 = hasher.clone().hash_address_to_partition(&pk);
-        let b2 = hasher.hash_address_to_partition(&pk);
-        assert_eq!(b1, b2);
-
-        // make sure b1 includes the seed's hash
-        let mut hasher = SipHasher13::new();
-        hasher.write(seed.as_ref());
-        hasher.write(pk.as_ref());
-        let partition = hash_to_partition(hasher.finish(), partitions);
-        assert_eq!(partition, b1);
-    }
+    use {super::*, solana_accounts_db::stake_rewards::StakeReward, std::collections::HashMap};
 
     #[test]
     fn test_hash_rewards_into_partitions() {

sdk/Cargo.toml

@@ -75,6 +75,7 @@ serde_json = { workspace = true, optional = true }
 serde_with = { workspace = true, features = ["macros"] }
 sha2 = { workspace = true }
 sha3 = { workspace = true, optional = true }
+siphasher = { workspace = true }
 solana-frozen-abi = { workspace = true }
 solana-frozen-abi-macro = { workspace = true }
 solana-logger = { workspace = true, optional = true }