hashable.js

/* FNV-1 hash
*
* The FNV-1 hash description: http://isthe.com/chongo/tech/comp/fnv/
* The FNV-1 hash is public domain: http://isthe.com/chongo/tech/comp/fnv/#public_domain

long hashable_fnv_hash(const unsigned char* str, long len, long hash) {

  while (len--) {
    hash = (hash * 16777619) ^ *str++;
  }

  return hash;
}
*/

function h$hashable_fnv_hash(str, len, hashInit) {
    var hash = hashInit;
    var i;
    for (i = 0; i < len; i++) {
        hash = (hash * 16777619) ^ str[i];
    }
    return hash;
}

/* Used for ByteArray#s. We can't treat them like pointers in
native Haskell, but we can in unsafe FFI calls.

long hashable_fnv_hash_offset(const unsigned char* str, long offset, long len, long hash) {
  return hashable_fnv_hash(str + offset, len, hash);
}
*/

function h$hashable_fnv_hash_offset(str, offset, len, hash) {
    return h$hashable_fnv_hash(str.substring(offset), len, hash);
}