basic murmur hash function
Sure! Here's an implementation of the MurmurHash function in BASIC:
FUNCTION MurmurHash3_x86_32(key AS STRING, seed AS INTEGER) AS INTEGER
CONST c1 = &HCC9E2D51
CONST c2 = &H1B873593
CONST r1 = 15
CONST r2 = 13
CONST m = &H5BD1E995
CONST n = 0xE6546B64
DIM h AS INTEGER = seed
DIM k AS INTEGER
FOR i = 1 TO LEN(key) STEP 4
k = ASC(MID(key, i, 1)) OR (ASC(MID(key, i + 1, 1)) << 8) OR (ASC(MID(key, i + 2, 1)) << 16) OR (ASC(MID(key, i + 3, 1)) << 24)
k = (k * c1) AND &HFFFFFFFF
k = (k << r1) OR ((k >> (32 - r1)) AND &HFFFFFFFF)
k = (k * c2) AND &HFFFFFFFF
h = (h XOR k)
h = (h << r2) OR ((h >> (32 - r2)) AND &HFFFFFFFF)
h = ((h * m) + n) AND &HFFFFFFFF
NEXT
h = h XOR LEN(key)
h = h XOR (h >> 16)
h = (h * &H85EBCA6B) AND &HFFFFFFFF
h = h XOR (h >> 13)
h = (h * &HC2B2AE35) AND &HFFFFFFFF
h = h XOR (h >> 16)
RETURN h
END FUNCTION
This implementation of the MurmurHash3_x86_32 function takes a key (as a string) and a seed (as an integer) as input. It then iterates over the key in chunks of 4 characters, converting each chunk to a 32-bit integer. The algorithm applies a series of bitwise operations and multiplications to the integer, XORing it with a hash value and updating the hash value accordingly.
Finally, the hash value is XORed with the length of the key and undergoes a series of additional bitwise operations and multiplications to produce the final hash value, which is then returned.
This implementation is based on the 32-bit version of the MurmurHash3 algorithm, which is commonly used for hash-based algorithms and data structures.
I hope this code snippet helps! Let me know if you have any further questions.