Function hash_string_masked

nodedb-array/src/coord/string_hash.rs:24–28

Hash `s` into the range `[0, bound]` (inclusive) by masking with `bound`. Caller passes `bound = (1 << bits) - 1` for power-of-two curve buckets, or `extent - 1` style values for tile bucketing (where `bound + 1` is a power of two); for arbitrary `bound`, callers should use [`hash_string_modulo`] instead.

(s: &str, bound: u64)

/// (where `bound + 1` is a power of two); for arbitrary `bound`,
/// callers should use [`hash_string_modulo`] instead.
pub fn hash_string_masked(s: &str, bound: u64) -> u64 {
    let mut h = std::collections::hash_map::RandomState::new().build_hasher();
    h.write(s.as_bytes());
    if bound == 0 { 0 } else { h.finish() & bound }
}

/// Hash `s` into `[0, modulus)` via modulo. Used by tile-index
/// bucketing where the extent isn't necessarily a power of two.