luoyuxia commented on code in PR #117: URL: https://github.com/apache/fluss-rust/pull/117#discussion_r2649465562
########## crates/fluss/src/util/murmur_hash.rs: ########## @@ -0,0 +1,211 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +/* This file is based on source code of Apache Flink Project (https://flink.apache.org/), licensed by the Apache + * Software Foundation (ASF) under the Apache License, Version 2.0. See the NOTICE file distributed with this work for + * additional information regarding copyright ownership. */ + +pub const MURMUR3_DEFAULT_SEED: i32 = 0; +pub const FLINK_MURMUR3_DEFAULT_SEED: i32 = 42; + +const C1: i32 = 0xCC9E_2D51_u32 as i32; +const C2: i32 = 0x1B87_3593; +const R1: u32 = 15; +const R2: u32 = 13; +const M: i32 = 5; +const N: i32 = 0xE654_6B64_u32 as i32; +const CHUNK_SIZE: usize = 4; + +/// Hashes the data using 32-bit Murmur3 hash with 0 as seed +/// +/// # Arguments +/// * `data` - byte array containing data to be hashed +/// +/// # Returns +/// Returns hash value +pub fn hash_bytes(data: &[u8]) -> i32 { + hash_bytes_with_seed(data, MURMUR3_DEFAULT_SEED) +} + +#[inline(always)] +fn hash_bytes_with_seed(data: &[u8], seed: i32) -> i32 { + let length = data.len(); + let chunks = length / CHUNK_SIZE; + let length_aligned = chunks * CHUNK_SIZE; + + let mut h1 = hash_full_chunks(data, seed, length_aligned); + let mut k1 = 0i32; + + for (shift, &b) in data[length_aligned..].iter().enumerate() { + k1 |= (b as i32) << (8 * shift); + } + + h1 ^= k1.wrapping_mul(C1).rotate_left(R1).wrapping_mul(C2); + + fmix(h1, length) Review Comment: The stardard murmur3 should use `u32` instead `i32`, when the length is greater than i32`, the current implementation won't align with stardard murmur3. Maybe two solution: option1: align the implementation to use `u32`, but note that the flink(fluss) hash should still use `i32` to align with their implemention. option2: still keep the current code, but add a important note that it only works for bytes that not larger than 2G. I prefer option1 since it's the right implemetation and I think it won't cause too much rework. ########## crates/fluss/src/util/murmur_hash.rs: ########## @@ -0,0 +1,211 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +/* This file is based on source code of Apache Flink Project (https://flink.apache.org/), licensed by the Apache + * Software Foundation (ASF) under the Apache License, Version 2.0. See the NOTICE file distributed with this work for + * additional information regarding copyright ownership. */ + +pub const MURMUR3_DEFAULT_SEED: i32 = 0; +pub const FLINK_MURMUR3_DEFAULT_SEED: i32 = 42; + +const C1: i32 = 0xCC9E_2D51_u32 as i32; +const C2: i32 = 0x1B87_3593; +const R1: u32 = 15; +const R2: u32 = 13; +const M: i32 = 5; +const N: i32 = 0xE654_6B64_u32 as i32; +const CHUNK_SIZE: usize = 4; + +/// Hashes the data using 32-bit Murmur3 hash with 0 as seed +/// +/// # Arguments +/// * `data` - byte array containing data to be hashed +/// +/// # Returns +/// Returns hash value +pub fn hash_bytes(data: &[u8]) -> i32 { + hash_bytes_with_seed(data, MURMUR3_DEFAULT_SEED) +} + +#[inline(always)] +fn hash_bytes_with_seed(data: &[u8], seed: i32) -> i32 { + let length = data.len(); + let chunks = length / CHUNK_SIZE; + let length_aligned = chunks * CHUNK_SIZE; + + let mut h1 = hash_full_chunks(data, seed, length_aligned); + let mut k1 = 0i32; + + for (shift, &b) in data[length_aligned..].iter().enumerate() { + k1 |= (b as i32) << (8 * shift); + } + + h1 ^= k1.wrapping_mul(C1).rotate_left(R1).wrapping_mul(C2); + + fmix(h1, length) +} + +/// Hashes the data using Flink's variant of 32-bit Murmur hash with 42 as seed and tail bytes mixed into hash byte-by-byte +/// +/// # Arguments +/// * `data` - byte array containing data to be hashed +/// +/// # Returns +/// Returns hash value +pub fn flink_hash_bytes(data: &[u8]) -> i32 { Review Comment: flink_hash_bytes -> fluss_hash_bytes to avoid confuse. It's werid to have flink hash bytes in fluss client -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
