Hash Function

UCX implements the MurmurHash2 algorithm for computing hashes that are primarily used for CxMap. But it can be used for arbitrary custom scenarios, too.

Overview

#include <cx/hash_key.h>

void 	  cx_hash_murmur(CxHashKey *key);
CxHashKey cx_hash_key(const void *obj, size_t len);
CxHashKey cx_hash_key_str(const char *str);
CxHashKey cx_hash_key_bytes(const unsigned char *bytes, size_t len);
CxHashKey cx_hash_key_cxstr(cxstring str);

Description

The primary function for creating a CxHashKey structure is cx_hash_key(). The other functions do effectively the same, but

cx_hash_key_bytes() is strongly typed if you want to avoid passing void*
cx_hash_key_str() conveniently takes a C string and computes the length
cx_hash_key_cxstr() conveniently takes a UCX string

In all cases, the hash will be available in the hash field of the returned structure.

If you want to create a hash completely manually, you can initialize the data and len members of CxHashKey and call cx_hash_murmur(). It is not recommended to do so.

Example that is equivalent to CxHashKey key = cx_hash_str(mystring)

CxHashKey key;
key.data = mystring;
key.len = strlen(mystring);
cx_hash_murmur(&key);

Last modified: 06 April 2025