CityHash32

CityHash32 is a non-cryptographic hash function developed by Google. It is designed to be fast and efficient for hashing 32-bit values. The algorithm produces a 32-bit hash output. CityHash32 is part of the CityHash family of hash functions, which also includes CityHash64 and CityHash128. These functions are known for their speed on modern CPUs, particularly those with SSE instructions.

The primary goal of CityHash32 is to provide a good distribution of hash values with a low collision rate for general-purpose hashing tasks, such as in hash tables or data integrity checks where cryptographic security is not a requirement. It is not designed to be resistant to malicious attacks or preimage resistance.

CityHash32 works by processing the input data in blocks and combining them using a series of arithmetic and bitwise operations. The specific mixing functions and constants are chosen to ensure good avalanche effects, meaning small changes in the input result in significant changes in the output hash. This helps in achieving a more uniform distribution of hash values. The function is often implemented using portable C++ code, making it widely usable across different platforms. Its performance characteristics make it a suitable choice for scenarios where hashing speed is critical and the input data is not adversarial.