2362N/A * Copyright (c) 1999, 2007, Oracle and/or its affiliates. All rights reserved. 0N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 0N/A * This code is free software; you can redistribute it and/or modify it 0N/A * under the terms of the GNU General Public License version 2 only, as 2362N/A * published by the Free Software Foundation. Oracle designates this 0N/A * particular file as subject to the "Classpath" exception as provided 2362N/A * by Oracle in the LICENSE file that accompanied this code. 0N/A * This code is distributed in the hope that it will be useful, but WITHOUT 0N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 0N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 0N/A * version 2 for more details (a copy is included in the LICENSE file that 0N/A * accompanied this code). 0N/A * You should have received a copy of the GNU General Public License version 0N/A * 2 along with this work; if not, write to the Free Software Foundation, 0N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 2362N/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2362N/A * or visit www.oracle.com if you need additional information or have any 0N/A * A simple bit sieve used for finding prime number candidates. Allows setting 0N/A * and clearing of bits in a storage array. The size of the sieve is assumed to 0N/A * be constant to reduce overhead. All the bits of a new bitSieve are zero, and 0N/A * bits are removed from it by setting them. 0N/A * To reduce storage space and increase efficiency, no even numbers are 0N/A * represented in the sieve (each bit in the sieve represents an odd number). 0N/A * The relationship between the index of a bit and the number it represents is 0N/A * N = offset + (2*index + 1); 0N/A * Where N is the integer represented by a bit in the sieve, offset is some 0N/A * even integer offset indicating where the sieve begins, and index is the 0N/A * index of a bit in the sieve array. 0N/A * @author Michael McCloskey 0N/A * Stores the bits in this bitSieve. 0N/A * Length is how many bits this sieve holds. 0N/A * A small sieve used to filter out multiples of small primes in a search 0N/A * Construct a "small sieve" with a base of 0. This constructor is 0N/A * used internally to generate the set of "small primes" whose multiples 0N/A * are excluded from sieves generated by the main (package private) 0N/A * constructor, BitSieve(BigInteger base, int searchLen). The length 0N/A * of the sieve generated by this constructor was chosen for performance; 0N/A * it controls a tradeoff between how much time is spent constructing 0N/A * other sieves, and how much time is wasted testing composite candidates 0N/A * for primality. The length was chosen experimentally to yield good 0N/A // Mark 1 as composite 0N/A // Find primes and remove their multiples from sieve 0N/A * Construct a bit sieve of searchLen bits used for finding prime number 0N/A * candidates. The new sieve begins at the specified base, which must 0N/A * Candidates are indicated by clear bits in the sieve. As a candidates 0N/A * nonprimality is calculated, a bit is set in the sieve to eliminate 0N/A * it. To reduce storage space and increase efficiency, no even numbers 0N/A * are represented in the sieve (each bit in the sieve represents an 0N/A // Construct the large sieve at an even offset specified by base 0N/A // Calculate base mod convertedStep 0N/A // Take each multiple of step out of sieve 0N/A // Find next prime from small sieve 0N/A * Given a bit index return unit index containing it. 0N/A * Return a unit that masks the specified bit in its unit. 0N/A * Get the value of the bit at the specified index. 0N/A * Set the bit at the specified index. 0N/A * This method returns the index of the first clear bit in the search 0N/A * array that occurs at or after start. It will not search past the 0N/A * specified limit. It returns -1 if there is no such clear bit. 0N/A * Sieve a single set of multiples out of the sieve. Begin to remove 0N/A * multiples of the specified step starting at the specified start index, 0N/A * up to the specified limit. 0N/A * Test probable primes in the sieve and return successful candidates. 0N/A // Examine the sieve one long at a time to find possible primes 0N/A for (
int j=
0; j<
64; j++) {