1#!/usr/bin/env python2.6 2# 3# Copyright (C) 2011 The Android Open Source Project 4# 5# Licensed under the Apache License, Version 2.0 (the "License"); 6# you may not use this file except in compliance with the License. 7# You may obtain a copy of the License at 8# 9# http://www.apache.org/licenses/LICENSE-2.0 10# 11# Unless required by applicable law or agreed to in writing, software 12# distributed under the License is distributed on an "AS IS" BASIS, 13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14# See the License for the specific language governing permissions and 15# limitations under the License. 16# 17 18# 19# Generates a table of prime numbers for use in BasicHashtable.cpp. 20# 21# Each prime is chosen such that it is a little more than twice as large as 22# the previous prime in the table. This makes it easier to choose a new 23# hashtable size when the underlying array is grown by as nominal factor 24# of two each time. 25# 26 27def is_odd_prime(n): 28 limit = (n - 1) / 2 29 d = 3 30 while d <= limit: 31 if n % d == 0: 32 return False 33 d += 2 34 return True 35 36print "static size_t PRIMES[] = {" 37 38n = 5 39max = 2**31 - 1 40while n < max: 41 print " %d," % (n) 42 n = n * 2 + 1 43 while not is_odd_prime(n): 44 n += 2 45 46print " 0," 47print "};" 48