| #!/usr/bin/env python2.6 | |
| # | |
| # Copyright (C) 2011 The Android Open Source Project | |
| # | |
| # Licensed under the Apache License, Version 2.0 (the "License"); | |
| # you may not use this file except in compliance with the License. | |
| # You may obtain a copy of the License at | |
| # | |
| # http://www.apache.org/licenses/LICENSE-2.0 | |
| # | |
| # Unless required by applicable law or agreed to in writing, software | |
| # distributed under the License is distributed on an "AS IS" BASIS, | |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| # See the License for the specific language governing permissions and | |
| # limitations under the License. | |
| # | |
| # | |
| # Generates a table of prime numbers for use in BasicHashtable.cpp. | |
| # | |
| # Each prime is chosen such that it is a little more than twice as large as | |
| # the previous prime in the table. This makes it easier to choose a new | |
| # hashtable size when the underlying array is grown by as nominal factor | |
| # of two each time. | |
| # | |
| def is_odd_prime(n): | |
| limit = (n - 1) / 2 | |
| d = 3 | |
| while d <= limit: | |
| if n % d == 0: | |
| return False | |
| d += 2 | |
| return True | |
| print "static size_t PRIMES[] = {" | |
| n = 5 | |
| max = 2**31 - 1 | |
| while n < max: | |
| print " %d," % (n) | |
| n = n * 2 + 1 | |
| while not is_odd_prime(n): | |
| n += 2 | |
| print " 0," | |
| print "};" |