public int check_prefix(final byte[] key,int depth){
  int max_cmp=Math.min(Math.min(partial_len,Node.MAX_PREFIX_LEN),key.length - depth);
  int idx;
  for (idx=0; idx < max_cmp; idx++) {
    if (partial[idx] != key[depth + idx])     return idx;
  }
  return idx;
}

public int check_prefix ( final byte [ ] key , int depth ) { int max_cmp = Math . min ( Math . min ( partial_len , Node . MAX_PREFIX_LEN ) , key . length - depth ) ; int idx ; for ( idx = 0 ; idx < max_cmp ; idx ++ ) { if ( partial [ idx ] != key [ depth + idx ] ) return idx ; } return idx ; }
returns the number of prefix characters shared between the key and node .
