Module hash 

Constants

HASH_BASE

Fibonacci hashing constant for good bit distribution.

Functions

base_pow

Compute HASH_BASE^n using wrapping multiplication. Call once per format group to obtain the window_power argument for roll().

hash_token

Hash a token with optional case folding.

hash_window

Compute the initial polynomial hash of a window of token hashes. hash = h[0]*BASE^(n-1) + h[1]*BASE^(n-2) + … + h[n-1]*BASE^0 Uses wrapping arithmetic throughout.

roll

Roll the hash one position: remove outgoing (the token leaving the window), add incoming (the token entering the window).

token_hash

Compute a deterministic hash for a single token given its kind byte and value string. Uses xxh3_64 XORed with kind cast to u64.