Murmur

murmur is a pure Java implementation of all Murmur hashes, namely, Murmur1, Murmur2 and Murmur3. The library is a direct Java implementation of the C++ source code. Hash generation has been 100% unit tested against the hashes generated using the C++ code. The library should help in building bloom filters, or to just compute the hash for checking sanity of data, as Murmur3 is much faster than MD5 and SHA computations.

Why murmur?

murmur was developed as I could not find pure Java implementations for Murmur1 and Murmur2 hashes. Implementations were available for Murmur3 but for some of the legacy code that I maintain, I needed the Murmur1 and Murmur2 hashes. Thus, I ported the original implementations.

Features

• Pure Java implementations of various Murmur hashes
• 100% hash compatibility with original C++ code
• No dependencies

Usage

Murmur1

String str = "Hello, World!";
long hash = Murmur1.hash(bytes, bytes.length, SEED);

Murmur2

String str = "Hello, World!";
long hash = Murmur2.hash(bytes, bytes.length, SEED);
long hash = Murmur2.hash64(bytes, bytes.length, SEED);

Murmur3

String str = "Hello, World!";
long hash = Murmur3.hash_x86_32(bytes, bytes.length, SEED); // 64-bit hash

// returns 2 long values that contain the 128-bit hash
long[] hashes = Murmur3.hash_x64_128(bytes, bytes.length, SEED); // 128-bit hash

Performance

The MurmurPerformanceTests.java file contains tests to compute hashes of 1-million random type-4 UUIDs between various Murmur hashes, and MD5, SHA-1, SHA-256, and SHA-512 hashes.

The results of a sample run on my dev machine are as under:

Intel i7-2660 CPU @ 3.40Ghz
16-GB RAM
Windows 7, 64-bit, Service Pack 1
Oracle JDK 1.7.0_51 build 13, 64-bit Server VM

Downloads

The library can be downloaded from Maven Central using:

<dependency>
    <groupId>com.sangupta</groupId>
    <artifactId>murmur</artifactId>
    <version>1.0.0</version>
</dependency>

License

The library is released under the terms of Apache Public License Version 2.

License

The library is released under the terms of Apache Public License Version 2.