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2237 lines
55 KiB
Java
2237 lines
55 KiB
Java
// BigInteger.java -- an arbitrary-precision integer
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/* Copyright (C) 1999, 2000, 2001 Free Software Foundation
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This file is part of libgcj.
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This software is copyrighted work licensed under the terms of the
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Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
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details. */
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package java.math;
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import gnu.gcj.math.*;
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import java.util.Random;
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import java.io.ObjectInputStream;
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import java.io.ObjectOutputStream;
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import java.io.IOException;
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/**
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* @author Warren Levy <warrenl@cygnus.com>
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* @date December 20, 1999.
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*/
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/**
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* Written using on-line Java Platform 1.2 API Specification, as well
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* as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998) and
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* "Applied Cryptography, Second Edition" by Bruce Schneier (Wiley, 1996).
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*
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* Based primarily on IntNum.java BitOps.java by Per Bothner <per@bothner.com>
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* (found in Kawa 1.6.62).
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*
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* Status: Believed complete and correct.
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*/
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public class BigInteger extends Number implements Comparable
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{
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/** All integers are stored in 2's-complement form.
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* If words == null, the ival is the value of this BigInteger.
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* Otherwise, the first ival elements of words make the value
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* of this BigInteger, stored in little-endian order, 2's-complement form. */
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transient private int ival;
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transient private int[] words;
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// Serialization fields.
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private int bitCount = -1;
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private int bitLength = -1;
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private int firstNonzeroByteNum = -2;
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private int lowestSetBit = -2;
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private byte[] magnitude;
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private int signum;
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private static final long serialVersionUID = -8287574255936472291L;
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/** We pre-allocate integers in the range minFixNum..maxFixNum. */
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private static final int minFixNum = -100;
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private static final int maxFixNum = 1024;
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private static final int numFixNum = maxFixNum-minFixNum+1;
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private static final BigInteger[] smallFixNums = new BigInteger[numFixNum];
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static {
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for (int i = numFixNum; --i >= 0; )
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smallFixNums[i] = new BigInteger(i + minFixNum);
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}
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// JDK1.2
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public static final BigInteger ZERO = smallFixNums[-minFixNum];
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// JDK1.2
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public static final BigInteger ONE = smallFixNums[1 - minFixNum];
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/* Rounding modes: */
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private static final int FLOOR = 1;
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private static final int CEILING = 2;
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private static final int TRUNCATE = 3;
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private static final int ROUND = 4;
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/** When checking the probability of primes, it is most efficient to
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* first check the factoring of small primes, so we'll use this array.
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*/
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private static final int[] primes =
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{ 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43,
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47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107,
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109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181,
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191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251 };
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private BigInteger()
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{
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}
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/* Create a new (non-shared) BigInteger, and initialize to an int. */
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private BigInteger(int value)
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{
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ival = value;
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}
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public BigInteger(String val, int radix)
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{
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BigInteger result = valueOf(val, radix);
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this.ival = result.ival;
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this.words = result.words;
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}
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public BigInteger(String val)
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{
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this(val, 10);
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}
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/* Create a new (non-shared) BigInteger, and initialize from a byte array. */
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public BigInteger(byte[] val)
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{
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if (val == null || val.length < 1)
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throw new NumberFormatException();
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words = byteArrayToIntArray(val, val[0] < 0 ? -1 : 0);
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BigInteger result = make(words, words.length);
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this.ival = result.ival;
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this.words = result.words;
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}
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public BigInteger(int signum, byte[] magnitude)
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{
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if (magnitude == null || signum > 1 || signum < -1)
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throw new NumberFormatException();
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if (signum == 0)
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{
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int i;
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for (i = magnitude.length - 1; i >= 0 && magnitude[i] == 0; --i)
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;
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if (i >= 0)
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throw new NumberFormatException();
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return;
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}
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// Magnitude is always positive, so don't ever pass a sign of -1.
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words = byteArrayToIntArray(magnitude, 0);
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BigInteger result = make(words, words.length);
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this.ival = result.ival;
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this.words = result.words;
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if (signum < 0)
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setNegative();
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}
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public BigInteger(int numBits, Random rnd)
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{
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if (numBits < 0)
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throw new IllegalArgumentException();
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// Result is always positive so tack on an extra zero word, it will be
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// canonicalized out later if necessary.
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int nwords = numBits / 32 + 2;
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words = new int[nwords];
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words[--nwords] = 0;
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words[--nwords] = rnd.nextInt() >>> (numBits % 32);
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while (--nwords >= 0)
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words[nwords] = rnd.nextInt();
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BigInteger result = make(words, words.length);
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this.ival = result.ival;
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this.words = result.words;
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}
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public BigInteger(int bitLength, int certainty, Random rnd)
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{
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this(bitLength, rnd);
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// Keep going until we find a probable prime.
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while (true)
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{
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if (isProbablePrime(certainty))
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return;
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BigInteger next = new BigInteger(bitLength, rnd);
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this.ival = next.ival;
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this.words = next.words;
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}
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}
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/** Return a (possibly-shared) BigInteger with a given long value. */
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private static BigInteger make(long value)
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{
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if (value >= minFixNum && value <= maxFixNum)
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return smallFixNums[(int)value - minFixNum];
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int i = (int) value;
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if ((long)i == value)
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return new BigInteger(i);
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BigInteger result = alloc(2);
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result.ival = 2;
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result.words[0] = i;
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result.words[1] = (int) (value >> 32);
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return result;
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}
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// FIXME: Could simply rename 'make' method above as valueOf while
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// changing all instances of 'make'. Don't do this until this class
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// is done as the Kawa class this is based on has 'make' methods
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// with other parameters; wait to see if they are used in BigInteger.
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public static BigInteger valueOf(long val)
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{
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return make(val);
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}
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/** Make a canonicalized BigInteger from an array of words.
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* The array may be reused (without copying). */
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private static BigInteger make(int[] words, int len)
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{
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if (words == null)
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return make(len);
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len = BigInteger.wordsNeeded(words, len);
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if (len <= 1)
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return len == 0 ? ZERO : make(words[0]);
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BigInteger num = new BigInteger();
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num.words = words;
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num.ival = len;
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return num;
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}
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/** Convert a big-endian byte array to a little-endian array of words. */
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private static int[] byteArrayToIntArray(byte[] bytes, int sign)
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{
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// Determine number of words needed.
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int[] words = new int[(bytes.length + 3) / 4 + 1];
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int nwords = words.length;
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// For simplicity, tack on an extra word of sign at the front,
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// it will be canonicalized out later. */
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words[--nwords] = sign;
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// Create a int out of modulo 4 high order bytes.
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int bptr = 0;
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int word = sign;
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for (int i = bytes.length % 4; i > 0; --i, bptr++)
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word = (word << 8) | (((int) bytes[bptr]) & 0xff);
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words[--nwords] = word;
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// Elements remaining in byte[] are a multiple of 4.
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while (nwords > 0)
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words[--nwords] = bytes[bptr++] << 24 |
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(((int) bytes[bptr++]) & 0xff) << 16 |
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(((int) bytes[bptr++]) & 0xff) << 8 |
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(((int) bytes[bptr++]) & 0xff);
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return words;
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}
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/** Allocate a new non-shared BigInteger.
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* @param nwords number of words to allocate
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*/
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private static BigInteger alloc(int nwords)
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{
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if (nwords <= 1)
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return new BigInteger();
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BigInteger result = new BigInteger();
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result.words = new int[nwords];
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return result;
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}
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/** Change words.length to nwords.
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* We allow words.length to be upto nwords+2 without reallocating.
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*/
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private void realloc(int nwords)
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{
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if (nwords == 0)
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{
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if (words != null)
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{
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if (ival > 0)
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ival = words[0];
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words = null;
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}
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}
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else if (words == null
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|| words.length < nwords
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|| words.length > nwords + 2)
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{
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int[] new_words = new int [nwords];
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if (words == null)
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{
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new_words[0] = ival;
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ival = 1;
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}
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else
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{
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if (nwords < ival)
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ival = nwords;
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System.arraycopy(words, 0, new_words, 0, ival);
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}
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words = new_words;
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}
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}
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private final boolean isNegative()
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{
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return (words == null ? ival : words[ival - 1]) < 0;
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}
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public int signum()
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{
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int top = words == null ? ival : words[ival-1];
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if (top == 0 && words == null)
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return 0;
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return top < 0 ? -1 : 1;
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}
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private static int compareTo(BigInteger x, BigInteger y)
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{
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if (x.words == null && y.words == null)
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return x.ival < y.ival ? -1 : x.ival > y.ival ? 1 : 0;
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boolean x_negative = x.isNegative();
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boolean y_negative = y.isNegative();
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if (x_negative != y_negative)
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return x_negative ? -1 : 1;
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int x_len = x.words == null ? 1 : x.ival;
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int y_len = y.words == null ? 1 : y.ival;
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if (x_len != y_len)
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return (x_len > y_len) != x_negative ? 1 : -1;
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return MPN.cmp(x.words, y.words, x_len);
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}
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// JDK1.2
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public int compareTo(Object obj)
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{
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if (obj instanceof BigInteger)
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return compareTo(this, (BigInteger) obj);
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throw new ClassCastException();
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}
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public int compareTo(BigInteger val)
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{
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return compareTo(this, val);
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}
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public BigInteger min(BigInteger val)
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{
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return compareTo(this, val) < 0 ? this : val;
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}
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public BigInteger max(BigInteger val)
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{
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return compareTo(this, val) > 0 ? this : val;
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}
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private final boolean isOdd()
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{
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int low = words == null ? ival : words[0];
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return (low & 1) != 0;
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}
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private final boolean isZero()
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{
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return words == null && ival == 0;
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}
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private final boolean isOne()
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{
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return words == null && ival == 1;
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}
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private final boolean isMinusOne()
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{
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return words == null && ival == -1;
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}
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/** Calculate how many words are significant in words[0:len-1].
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* Returns the least value x such that x>0 && words[0:x-1]==words[0:len-1],
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* when words is viewed as a 2's complement integer.
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*/
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private static int wordsNeeded(int[] words, int len)
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{
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int i = len;
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if (i > 0)
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{
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int word = words[--i];
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if (word == -1)
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{
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while (i > 0 && (word = words[i - 1]) < 0)
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{
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i--;
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if (word != -1) break;
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}
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}
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else
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{
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while (word == 0 && i > 0 && (word = words[i - 1]) >= 0) i--;
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}
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}
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return i + 1;
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}
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private BigInteger canonicalize()
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{
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if (words != null
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&& (ival = BigInteger.wordsNeeded(words, ival)) <= 1)
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{
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if (ival == 1)
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ival = words[0];
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words = null;
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}
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if (words == null && ival >= minFixNum && ival <= maxFixNum)
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return smallFixNums[(int) ival - minFixNum];
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return this;
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}
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/** Add two ints, yielding a BigInteger. */
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private static final BigInteger add(int x, int y)
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{
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return BigInteger.make((long) x + (long) y);
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}
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/** Add a BigInteger and an int, yielding a new BigInteger. */
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private static BigInteger add(BigInteger x, int y)
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{
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if (x.words == null)
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return BigInteger.add(x.ival, y);
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BigInteger result = new BigInteger(0);
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result.setAdd(x, y);
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return result.canonicalize();
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}
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/** Set this to the sum of x and y.
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* OK if x==this. */
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private void setAdd(BigInteger x, int y)
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{
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if (x.words == null)
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{
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set((long) x.ival + (long) y);
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return;
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}
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int len = x.ival;
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realloc(len + 1);
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long carry = y;
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for (int i = 0; i < len; i++)
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{
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carry += ((long) x.words[i] & 0xffffffffL);
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words[i] = (int) carry;
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carry >>= 32;
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}
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if (x.words[len - 1] < 0)
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carry--;
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words[len] = (int) carry;
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ival = wordsNeeded(words, len + 1);
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}
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/** Destructively add an int to this. */
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private final void setAdd(int y)
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{
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setAdd(this, y);
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}
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/** Destructively set the value of this to a long. */
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private final void set(long y)
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{
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int i = (int) y;
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if ((long) i == y)
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{
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ival = i;
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words = null;
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}
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else
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{
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realloc(2);
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words[0] = i;
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words[1] = (int) (y >> 32);
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ival = 2;
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}
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}
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/** Destructively set the value of this to the given words.
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* The words array is reused, not copied. */
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private final void set(int[] words, int length)
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{
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this.ival = length;
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this.words = words;
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}
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/** Destructively set the value of this to that of y. */
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private final void set(BigInteger y)
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{
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if (y.words == null)
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set(y.ival);
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else if (this != y)
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{
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realloc(y.ival);
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System.arraycopy(y.words, 0, words, 0, y.ival);
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ival = y.ival;
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}
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}
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/** Add two BigIntegers, yielding their sum as another BigInteger. */
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private static BigInteger add(BigInteger x, BigInteger y, int k)
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{
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if (x.words == null && y.words == null)
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return BigInteger.make((long) k * (long) y.ival + (long) x.ival);
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if (k != 1)
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{
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if (k == -1)
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y = BigInteger.neg(y);
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else
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y = BigInteger.times(y, BigInteger.make(k));
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}
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if (x.words == null)
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return BigInteger.add(y, x.ival);
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if (y.words == null)
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return BigInteger.add(x, y.ival);
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// Both are big
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int len;
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if (y.ival > x.ival)
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{ // Swap so x is longer then y.
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BigInteger tmp = x; x = y; y = tmp;
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}
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BigInteger result = alloc(x.ival + 1);
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int i = y.ival;
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long carry = MPN.add_n(result.words, x.words, y.words, i);
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long y_ext = y.words[i - 1] < 0 ? 0xffffffffL : 0;
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for (; i < x.ival; i++)
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{
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carry += ((long) x.words[i] & 0xffffffffL) + y_ext;;
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result.words[i] = (int) carry;
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carry >>>= 32;
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}
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if (x.words[i - 1] < 0)
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y_ext--;
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result.words[i] = (int) (carry + y_ext);
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result.ival = i+1;
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return result.canonicalize();
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}
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public BigInteger add(BigInteger val)
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{
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return add(this, val, 1);
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}
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public BigInteger subtract(BigInteger val)
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{
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return add(this, val, -1);
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}
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private static final BigInteger times(BigInteger x, int y)
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{
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if (y == 0)
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return ZERO;
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if (y == 1)
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return x;
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int[] xwords = x.words;
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int xlen = x.ival;
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if (xwords == null)
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return BigInteger.make((long) xlen * (long) y);
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boolean negative;
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BigInteger result = BigInteger.alloc(xlen + 1);
|
|
if (xwords[xlen - 1] < 0)
|
|
{
|
|
negative = true;
|
|
negate(result.words, xwords, xlen);
|
|
xwords = result.words;
|
|
}
|
|
else
|
|
negative = false;
|
|
if (y < 0)
|
|
{
|
|
negative = !negative;
|
|
y = -y;
|
|
}
|
|
result.words[xlen] = MPN.mul_1(result.words, xwords, xlen, y);
|
|
result.ival = xlen + 1;
|
|
if (negative)
|
|
result.setNegative();
|
|
return result.canonicalize();
|
|
}
|
|
|
|
private static final BigInteger times(BigInteger x, BigInteger y)
|
|
{
|
|
if (y.words == null)
|
|
return times(x, y.ival);
|
|
if (x.words == null)
|
|
return times(y, x.ival);
|
|
boolean negative = false;
|
|
int[] xwords;
|
|
int[] ywords;
|
|
int xlen = x.ival;
|
|
int ylen = y.ival;
|
|
if (x.isNegative())
|
|
{
|
|
negative = true;
|
|
xwords = new int[xlen];
|
|
negate(xwords, x.words, xlen);
|
|
}
|
|
else
|
|
{
|
|
negative = false;
|
|
xwords = x.words;
|
|
}
|
|
if (y.isNegative())
|
|
{
|
|
negative = !negative;
|
|
ywords = new int[ylen];
|
|
negate(ywords, y.words, ylen);
|
|
}
|
|
else
|
|
ywords = y.words;
|
|
// Swap if x is shorter then y.
|
|
if (xlen < ylen)
|
|
{
|
|
int[] twords = xwords; xwords = ywords; ywords = twords;
|
|
int tlen = xlen; xlen = ylen; ylen = tlen;
|
|
}
|
|
BigInteger result = BigInteger.alloc(xlen+ylen);
|
|
MPN.mul(result.words, xwords, xlen, ywords, ylen);
|
|
result.ival = xlen+ylen;
|
|
if (negative)
|
|
result.setNegative();
|
|
return result.canonicalize();
|
|
}
|
|
|
|
public BigInteger multiply(BigInteger y)
|
|
{
|
|
return times(this, y);
|
|
}
|
|
|
|
private static void divide(long x, long y,
|
|
BigInteger quotient, BigInteger remainder,
|
|
int rounding_mode)
|
|
{
|
|
boolean xNegative, yNegative;
|
|
if (x < 0)
|
|
{
|
|
xNegative = true;
|
|
if (x == Long.MIN_VALUE)
|
|
{
|
|
divide(BigInteger.make(x), BigInteger.make(y),
|
|
quotient, remainder, rounding_mode);
|
|
return;
|
|
}
|
|
x = -x;
|
|
}
|
|
else
|
|
xNegative = false;
|
|
|
|
if (y < 0)
|
|
{
|
|
yNegative = true;
|
|
if (y == Long.MIN_VALUE)
|
|
{
|
|
if (rounding_mode == TRUNCATE)
|
|
{ // x != Long.Min_VALUE implies abs(x) < abs(y)
|
|
if (quotient != null)
|
|
quotient.set(0);
|
|
if (remainder != null)
|
|
remainder.set(x);
|
|
}
|
|
else
|
|
divide(BigInteger.make(x), BigInteger.make(y),
|
|
quotient, remainder, rounding_mode);
|
|
return;
|
|
}
|
|
y = -y;
|
|
}
|
|
else
|
|
yNegative = false;
|
|
|
|
long q = x / y;
|
|
long r = x % y;
|
|
boolean qNegative = xNegative ^ yNegative;
|
|
|
|
boolean add_one = false;
|
|
if (r != 0)
|
|
{
|
|
switch (rounding_mode)
|
|
{
|
|
case TRUNCATE:
|
|
break;
|
|
case CEILING:
|
|
case FLOOR:
|
|
if (qNegative == (rounding_mode == FLOOR))
|
|
add_one = true;
|
|
break;
|
|
case ROUND:
|
|
add_one = r > ((y - (q & 1)) >> 1);
|
|
break;
|
|
}
|
|
}
|
|
if (quotient != null)
|
|
{
|
|
if (add_one)
|
|
q++;
|
|
if (qNegative)
|
|
q = -q;
|
|
quotient.set(q);
|
|
}
|
|
if (remainder != null)
|
|
{
|
|
// The remainder is by definition: X-Q*Y
|
|
if (add_one)
|
|
{
|
|
// Subtract the remainder from Y.
|
|
r = y - r;
|
|
// In this case, abs(Q*Y) > abs(X).
|
|
// So sign(remainder) = -sign(X).
|
|
xNegative = ! xNegative;
|
|
}
|
|
else
|
|
{
|
|
// If !add_one, then: abs(Q*Y) <= abs(X).
|
|
// So sign(remainder) = sign(X).
|
|
}
|
|
if (xNegative)
|
|
r = -r;
|
|
remainder.set(r);
|
|
}
|
|
}
|
|
|
|
/** Divide two integers, yielding quotient and remainder.
|
|
* @param x the numerator in the division
|
|
* @param y the denominator in the division
|
|
* @param quotient is set to the quotient of the result (iff quotient!=null)
|
|
* @param remainder is set to the remainder of the result
|
|
* (iff remainder!=null)
|
|
* @param rounding_mode one of FLOOR, CEILING, TRUNCATE, or ROUND.
|
|
*/
|
|
private static void divide(BigInteger x, BigInteger y,
|
|
BigInteger quotient, BigInteger remainder,
|
|
int rounding_mode)
|
|
{
|
|
if ((x.words == null || x.ival <= 2)
|
|
&& (y.words == null || y.ival <= 2))
|
|
{
|
|
long x_l = x.longValue();
|
|
long y_l = y.longValue();
|
|
if (x_l != Long.MIN_VALUE && y_l != Long.MIN_VALUE)
|
|
{
|
|
divide(x_l, y_l, quotient, remainder, rounding_mode);
|
|
return;
|
|
}
|
|
}
|
|
|
|
boolean xNegative = x.isNegative();
|
|
boolean yNegative = y.isNegative();
|
|
boolean qNegative = xNegative ^ yNegative;
|
|
|
|
int ylen = y.words == null ? 1 : y.ival;
|
|
int[] ywords = new int[ylen];
|
|
y.getAbsolute(ywords);
|
|
while (ylen > 1 && ywords[ylen - 1] == 0) ylen--;
|
|
|
|
int xlen = x.words == null ? 1 : x.ival;
|
|
int[] xwords = new int[xlen+2];
|
|
x.getAbsolute(xwords);
|
|
while (xlen > 1 && xwords[xlen-1] == 0) xlen--;
|
|
|
|
int qlen, rlen;
|
|
|
|
int cmpval = MPN.cmp(xwords, xlen, ywords, ylen);
|
|
if (cmpval < 0) // abs(x) < abs(y)
|
|
{ // quotient = 0; remainder = num.
|
|
int[] rwords = xwords; xwords = ywords; ywords = rwords;
|
|
rlen = xlen; qlen = 1; xwords[0] = 0;
|
|
}
|
|
else if (cmpval == 0) // abs(x) == abs(y)
|
|
{
|
|
xwords[0] = 1; qlen = 1; // quotient = 1
|
|
ywords[0] = 0; rlen = 1; // remainder = 0;
|
|
}
|
|
else if (ylen == 1)
|
|
{
|
|
qlen = xlen;
|
|
// Need to leave room for a word of leading zeros if dividing by 1
|
|
// and the dividend has the high bit set. It might be safe to
|
|
// increment qlen in all cases, but it certainly is only necessary
|
|
// in the following case.
|
|
if (ywords[0] == 1 && xwords[xlen-1] < 0)
|
|
qlen++;
|
|
rlen = 1;
|
|
ywords[0] = MPN.divmod_1(xwords, xwords, xlen, ywords[0]);
|
|
}
|
|
else // abs(x) > abs(y)
|
|
{
|
|
// Normalize the denominator, i.e. make its most significant bit set by
|
|
// shifting it normalization_steps bits to the left. Also shift the
|
|
// numerator the same number of steps (to keep the quotient the same!).
|
|
|
|
int nshift = MPN.count_leading_zeros(ywords[ylen - 1]);
|
|
if (nshift != 0)
|
|
{
|
|
// Shift up the denominator setting the most significant bit of
|
|
// the most significant word.
|
|
MPN.lshift(ywords, 0, ywords, ylen, nshift);
|
|
|
|
// Shift up the numerator, possibly introducing a new most
|
|
// significant word.
|
|
int x_high = MPN.lshift(xwords, 0, xwords, xlen, nshift);
|
|
xwords[xlen++] = x_high;
|
|
}
|
|
|
|
if (xlen == ylen)
|
|
xwords[xlen++] = 0;
|
|
MPN.divide(xwords, xlen, ywords, ylen);
|
|
rlen = ylen;
|
|
if (remainder != null || rounding_mode != TRUNCATE)
|
|
{
|
|
if (nshift == 0)
|
|
System.arraycopy(xwords, 0, ywords, 0, rlen);
|
|
else
|
|
MPN.rshift(ywords, xwords, 0, rlen, nshift);
|
|
}
|
|
|
|
qlen = xlen + 1 - ylen;
|
|
if (quotient != null)
|
|
{
|
|
for (int i = 0; i < qlen; i++)
|
|
xwords[i] = xwords[i+ylen];
|
|
}
|
|
}
|
|
|
|
// Now the quotient is in xwords, and the remainder is in ywords.
|
|
|
|
boolean add_one = false;
|
|
if (rlen > 1 || ywords[0] != 0)
|
|
{ // Non-zero remainder i.e. in-exact quotient.
|
|
switch (rounding_mode)
|
|
{
|
|
case TRUNCATE:
|
|
break;
|
|
case CEILING:
|
|
case FLOOR:
|
|
if (qNegative == (rounding_mode == FLOOR))
|
|
add_one = true;
|
|
break;
|
|
case ROUND:
|
|
// int cmp = compareTo(remainder<<1, abs(y));
|
|
BigInteger tmp = remainder == null ? new BigInteger() : remainder;
|
|
tmp.set(ywords, rlen);
|
|
tmp = shift(tmp, 1);
|
|
if (yNegative)
|
|
tmp.setNegative();
|
|
int cmp = compareTo(tmp, y);
|
|
// Now cmp == compareTo(sign(y)*(remainder<<1), y)
|
|
if (yNegative)
|
|
cmp = -cmp;
|
|
add_one = (cmp == 1) || (cmp == 0 && (xwords[0]&1) != 0);
|
|
}
|
|
}
|
|
if (quotient != null)
|
|
{
|
|
quotient.set(xwords, qlen);
|
|
if (qNegative)
|
|
{
|
|
if (add_one) // -(quotient + 1) == ~(quotient)
|
|
quotient.setInvert();
|
|
else
|
|
quotient.setNegative();
|
|
}
|
|
else if (add_one)
|
|
quotient.setAdd(1);
|
|
}
|
|
if (remainder != null)
|
|
{
|
|
// The remainder is by definition: X-Q*Y
|
|
remainder.set(ywords, rlen);
|
|
if (add_one)
|
|
{
|
|
// Subtract the remainder from Y:
|
|
// abs(R) = abs(Y) - abs(orig_rem) = -(abs(orig_rem) - abs(Y)).
|
|
BigInteger tmp;
|
|
if (y.words == null)
|
|
{
|
|
tmp = remainder;
|
|
tmp.set(yNegative ? ywords[0] + y.ival : ywords[0] - y.ival);
|
|
}
|
|
else
|
|
tmp = BigInteger.add(remainder, y, yNegative ? 1 : -1);
|
|
// Now tmp <= 0.
|
|
// In this case, abs(Q) = 1 + floor(abs(X)/abs(Y)).
|
|
// Hence, abs(Q*Y) > abs(X).
|
|
// So sign(remainder) = -sign(X).
|
|
if (xNegative)
|
|
remainder.setNegative(tmp);
|
|
else
|
|
remainder.set(tmp);
|
|
}
|
|
else
|
|
{
|
|
// If !add_one, then: abs(Q*Y) <= abs(X).
|
|
// So sign(remainder) = sign(X).
|
|
if (xNegative)
|
|
remainder.setNegative();
|
|
}
|
|
}
|
|
}
|
|
|
|
public BigInteger divide(BigInteger val)
|
|
{
|
|
if (val.isZero())
|
|
throw new ArithmeticException("divisor is zero");
|
|
|
|
BigInteger quot = new BigInteger();
|
|
divide(this, val, quot, null, TRUNCATE);
|
|
return quot.canonicalize();
|
|
}
|
|
|
|
public BigInteger remainder(BigInteger val)
|
|
{
|
|
if (val.isZero())
|
|
throw new ArithmeticException("divisor is zero");
|
|
|
|
BigInteger rem = new BigInteger();
|
|
divide(this, val, null, rem, TRUNCATE);
|
|
return rem.canonicalize();
|
|
}
|
|
|
|
public BigInteger[] divideAndRemainder(BigInteger val)
|
|
{
|
|
if (val.isZero())
|
|
throw new ArithmeticException("divisor is zero");
|
|
|
|
BigInteger[] result = new BigInteger[2];
|
|
result[0] = new BigInteger();
|
|
result[1] = new BigInteger();
|
|
divide(this, val, result[0], result[1], TRUNCATE);
|
|
result[0].canonicalize();
|
|
result[1].canonicalize();
|
|
return result;
|
|
}
|
|
|
|
public BigInteger mod(BigInteger m)
|
|
{
|
|
if (m.isNegative() || m.isZero())
|
|
throw new ArithmeticException("non-positive modulus");
|
|
|
|
BigInteger rem = new BigInteger();
|
|
divide(this, m, null, rem, FLOOR);
|
|
return rem.canonicalize();
|
|
}
|
|
|
|
/** Calculate power for BigInteger exponents.
|
|
* @param y exponent assumed to be non-negative. */
|
|
private BigInteger pow(BigInteger y)
|
|
{
|
|
if (isOne())
|
|
return this;
|
|
if (isMinusOne())
|
|
return y.isOdd () ? this : ONE;
|
|
if (y.words == null && y.ival >= 0)
|
|
return pow(y.ival);
|
|
|
|
// Assume exponent is non-negative.
|
|
if (isZero())
|
|
return this;
|
|
|
|
// Implemented by repeated squaring and multiplication.
|
|
BigInteger pow2 = this;
|
|
BigInteger r = null;
|
|
for (;;) // for (i = 0; ; i++)
|
|
{
|
|
// pow2 == x**(2**i)
|
|
// prod = x**(sum(j=0..i-1, (y>>j)&1))
|
|
if (y.isOdd())
|
|
r = r == null ? pow2 : times(r, pow2); // r *= pow2
|
|
y = BigInteger.shift(y, -1);
|
|
if (y.isZero())
|
|
break;
|
|
// pow2 *= pow2;
|
|
pow2 = times(pow2, pow2);
|
|
}
|
|
return r == null ? ONE : r;
|
|
}
|
|
|
|
/** Calculate the integral power of a BigInteger.
|
|
* @param exponent the exponent (must be non-negative)
|
|
*/
|
|
public BigInteger pow(int exponent)
|
|
{
|
|
if (exponent <= 0)
|
|
{
|
|
if (exponent == 0)
|
|
return ONE;
|
|
else
|
|
throw new ArithmeticException("negative exponent");
|
|
}
|
|
if (isZero())
|
|
return this;
|
|
int plen = words == null ? 1 : ival; // Length of pow2.
|
|
int blen = ((bitLength() * exponent) >> 5) + 2 * plen;
|
|
boolean negative = isNegative() && (exponent & 1) != 0;
|
|
int[] pow2 = new int [blen];
|
|
int[] rwords = new int [blen];
|
|
int[] work = new int [blen];
|
|
getAbsolute(pow2); // pow2 = abs(this);
|
|
int rlen = 1;
|
|
rwords[0] = 1; // rwords = 1;
|
|
for (;;) // for (i = 0; ; i++)
|
|
{
|
|
// pow2 == this**(2**i)
|
|
// prod = this**(sum(j=0..i-1, (exponent>>j)&1))
|
|
if ((exponent & 1) != 0)
|
|
{ // r *= pow2
|
|
MPN.mul(work, pow2, plen, rwords, rlen);
|
|
int[] temp = work; work = rwords; rwords = temp;
|
|
rlen += plen;
|
|
while (rwords[rlen - 1] == 0) rlen--;
|
|
}
|
|
exponent >>= 1;
|
|
if (exponent == 0)
|
|
break;
|
|
// pow2 *= pow2;
|
|
MPN.mul(work, pow2, plen, pow2, plen);
|
|
int[] temp = work; work = pow2; pow2 = temp; // swap to avoid a copy
|
|
plen *= 2;
|
|
while (pow2[plen - 1] == 0) plen--;
|
|
}
|
|
if (rwords[rlen - 1] < 0)
|
|
rlen++;
|
|
if (negative)
|
|
negate(rwords, rwords, rlen);
|
|
return BigInteger.make(rwords, rlen);
|
|
}
|
|
|
|
private static final int[] euclidInv(int a, int b, int prevDiv)
|
|
{
|
|
// Storage for return values, plus one slot for a temp int (see below).
|
|
int[] xy;
|
|
|
|
if (b == 0)
|
|
throw new ArithmeticException("not invertible");
|
|
else if (b == 1)
|
|
{
|
|
// Success: values are indeed invertible!
|
|
// Bottom of the recursion reached; start unwinding.
|
|
xy = new int[3];
|
|
xy[0] = -prevDiv;
|
|
xy[1] = 1;
|
|
return xy;
|
|
}
|
|
|
|
xy = euclidInv(b, a % b, a / b); // Recursion happens here.
|
|
|
|
// xy[2] is just temp storage for intermediate results in the following
|
|
// calculation. This saves us a bit of space over having an int
|
|
// allocated at every level of this recursive method.
|
|
xy[2] = xy[0];
|
|
xy[0] = xy[2] * -prevDiv + xy[1];
|
|
xy[1] = xy[2];
|
|
return xy;
|
|
}
|
|
|
|
private static final BigInteger[]
|
|
euclidInv(BigInteger a, BigInteger b, BigInteger prevDiv)
|
|
{
|
|
// FIXME: This method could be more efficient memory-wise and should be
|
|
// modified as such since it is recursive.
|
|
|
|
// Storage for return values, plus one slot for a temp int (see below).
|
|
BigInteger[] xy;
|
|
|
|
if (b.isZero())
|
|
throw new ArithmeticException("not invertible");
|
|
else if (b.isOne())
|
|
{
|
|
// Success: values are indeed invertible!
|
|
// Bottom of the recursion reached; start unwinding.
|
|
xy = new BigInteger[3];
|
|
xy[0] = neg(prevDiv);
|
|
xy[1] = ONE;
|
|
return xy;
|
|
}
|
|
|
|
// Recursion happens in the following conditional!
|
|
|
|
// If a just contains an int, then use integer math for the rest.
|
|
if (a.words == null)
|
|
{
|
|
int[] xyInt = euclidInv(b.ival, a.ival % b.ival, a.ival / b.ival);
|
|
xy = new BigInteger[3];
|
|
xy[0] = new BigInteger(xyInt[0]);
|
|
xy[1] = new BigInteger(xyInt[1]);
|
|
}
|
|
else
|
|
{
|
|
BigInteger rem = new BigInteger();
|
|
BigInteger quot = new BigInteger();
|
|
divide(a, b, quot, rem, FLOOR);
|
|
xy = euclidInv(b, rem, quot);
|
|
}
|
|
|
|
// xy[2] is just temp storage for intermediate results in the following
|
|
// calculation. This saves us a bit of space over having a BigInteger
|
|
// allocated at every level of this recursive method.
|
|
xy[2] = xy[0];
|
|
xy[0] = add(xy[1], times(xy[2], prevDiv), -1);
|
|
xy[1] = xy[2];
|
|
return xy;
|
|
}
|
|
|
|
public BigInteger modInverse(BigInteger y)
|
|
{
|
|
if (y.isNegative() || y.isZero())
|
|
throw new ArithmeticException("non-positive modulo");
|
|
|
|
// Degenerate cases.
|
|
if (y.isOne())
|
|
return ZERO;
|
|
else if (isOne())
|
|
return ONE;
|
|
|
|
// Use Euclid's algorithm as in gcd() but do this recursively
|
|
// rather than in a loop so we can use the intermediate results as we
|
|
// unwind from the recursion.
|
|
// Used http://www.math.nmsu.edu/~crypto/EuclideanAlgo.html as reference.
|
|
BigInteger result = new BigInteger();
|
|
int xval = ival;
|
|
int yval = y.ival;
|
|
boolean swapped = false;
|
|
|
|
if (y.words == null)
|
|
{
|
|
// The result is guaranteed to be less than the modulus, y (which is
|
|
// an int), so simplify this by working with the int result of this
|
|
// modulo y. Also, if this is negative, make it positive via modulo
|
|
// math. Note that BigInteger.mod() must be used even if this is
|
|
// already an int as the % operator would provide a negative result if
|
|
// this is negative, BigInteger.mod() never returns negative values.
|
|
if (words != null || isNegative())
|
|
xval = mod(y).ival;
|
|
|
|
// Swap values so x > y.
|
|
if (yval > xval)
|
|
{
|
|
int tmp = xval; xval = yval; yval = tmp;
|
|
swapped = true;
|
|
}
|
|
// Normally, the result is in the 2nd element of the array, but
|
|
// if originally x < y, then x and y were swapped and the result
|
|
// is in the 1st element of the array.
|
|
result.ival =
|
|
euclidInv(yval, xval % yval, xval / yval)[swapped ? 0 : 1];
|
|
|
|
// Result can't be negative, so make it positive by adding the
|
|
// original modulus, y.ival (not the possibly "swapped" yval).
|
|
if (result.ival < 0)
|
|
result.ival += y.ival;
|
|
}
|
|
else
|
|
{
|
|
BigInteger x = this;
|
|
|
|
// As above, force this to be a positive value via modulo math.
|
|
if (isNegative())
|
|
x = mod(y);
|
|
|
|
// Swap values so x > y.
|
|
if (x.compareTo(y) < 0)
|
|
{
|
|
BigInteger tmp = x; x = y; y = tmp;
|
|
swapped = true;
|
|
}
|
|
// As above (for ints), result will be in the 2nd element unless
|
|
// the original x and y were swapped.
|
|
BigInteger rem = new BigInteger();
|
|
BigInteger quot = new BigInteger();
|
|
divide(x, y, quot, rem, FLOOR);
|
|
result = euclidInv(y, rem, quot)[swapped ? 0 : 1];
|
|
|
|
// Result can't be negative, so make it positive by adding the
|
|
// original modulus, y (which is now x if they were swapped).
|
|
if (result.isNegative())
|
|
result = add(result, swapped ? x : y, 1);
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
public BigInteger modPow(BigInteger exponent, BigInteger m)
|
|
{
|
|
if (m.isNegative() || m.isZero())
|
|
throw new ArithmeticException("non-positive modulo");
|
|
|
|
if (exponent.isNegative())
|
|
return modInverse(m);
|
|
if (exponent.isOne())
|
|
return mod(m);
|
|
|
|
// To do this naively by first raising this to the power of exponent
|
|
// and then performing modulo m would be extremely expensive, especially
|
|
// for very large numbers. The solution is found in Number Theory
|
|
// where a combination of partial powers and modulos can be done easily.
|
|
//
|
|
// We'll use the algorithm for Additive Chaining which can be found on
|
|
// p. 244 of "Applied Cryptography, Second Edition" by Bruce Schneier.
|
|
BigInteger s, t, u;
|
|
int i;
|
|
|
|
s = ONE;
|
|
t = this;
|
|
u = exponent;
|
|
|
|
while (!u.isZero())
|
|
{
|
|
if (u.and(ONE).isOne())
|
|
s = times(s, t).mod(m);
|
|
u = u.shiftRight(1);
|
|
t = times(t, t).mod(m);
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
/** Calculate Greatest Common Divisor for non-negative ints. */
|
|
private static final int gcd(int a, int b)
|
|
{
|
|
// Euclid's algorithm, copied from libg++.
|
|
if (b > a)
|
|
{
|
|
int tmp = a; a = b; b = tmp;
|
|
}
|
|
for(;;)
|
|
{
|
|
if (b == 0)
|
|
return a;
|
|
else if (b == 1)
|
|
return b;
|
|
else
|
|
{
|
|
int tmp = b;
|
|
b = a % b;
|
|
a = tmp;
|
|
}
|
|
}
|
|
}
|
|
|
|
public BigInteger gcd(BigInteger y)
|
|
{
|
|
int xval = ival;
|
|
int yval = y.ival;
|
|
if (words == null)
|
|
{
|
|
if (xval == 0)
|
|
return BigInteger.abs(y);
|
|
if (y.words == null
|
|
&& xval != Integer.MIN_VALUE && yval != Integer.MIN_VALUE)
|
|
{
|
|
if (xval < 0)
|
|
xval = -xval;
|
|
if (yval < 0)
|
|
yval = -yval;
|
|
return BigInteger.make(BigInteger.gcd(xval, yval));
|
|
}
|
|
xval = 1;
|
|
}
|
|
if (y.words == null)
|
|
{
|
|
if (yval == 0)
|
|
return BigInteger.abs(this);
|
|
yval = 1;
|
|
}
|
|
int len = (xval > yval ? xval : yval) + 1;
|
|
int[] xwords = new int[len];
|
|
int[] ywords = new int[len];
|
|
getAbsolute(xwords);
|
|
y.getAbsolute(ywords);
|
|
len = MPN.gcd(xwords, ywords, len);
|
|
BigInteger result = new BigInteger(0);
|
|
result.ival = len;
|
|
result.words = xwords;
|
|
return result.canonicalize();
|
|
}
|
|
|
|
public boolean isProbablePrime(int certainty)
|
|
{
|
|
/** We'll use the Rabin-Miller algorithm for doing a probabilistic
|
|
* primality test. It is fast, easy and has faster decreasing odds of a
|
|
* composite passing than with other tests. This means that this
|
|
* method will actually have a probability much greater than the
|
|
* 1 - .5^certainty specified in the JCL (p. 117), but I don't think
|
|
* anyone will complain about better performance with greater certainty.
|
|
*
|
|
* The Rabin-Miller algorithm can be found on pp. 259-261 of "Applied
|
|
* Cryptography, Second Edition" by Bruce Schneier.
|
|
*/
|
|
|
|
// First rule out small prime factors and assure the number is odd.
|
|
for (int i = 0; i < primes.length; i++)
|
|
{
|
|
if (words == null && ival == primes[i])
|
|
return true;
|
|
if (remainder(make(primes[i])).isZero())
|
|
return false;
|
|
}
|
|
|
|
// Now perform the Rabin-Miller test.
|
|
// NB: I know that this can be simplified programatically, but
|
|
// I have tried to keep it as close as possible to the algorithm
|
|
// as written in the Schneier book for reference purposes.
|
|
|
|
// Set b to the number of times 2 evenly divides (this - 1).
|
|
// I.e. 2^b is the largest power of 2 that divides (this - 1).
|
|
BigInteger pMinus1 = add(this, -1);
|
|
int b = pMinus1.getLowestSetBit();
|
|
|
|
// Set m such that this = 1 + 2^b * m.
|
|
BigInteger m = pMinus1.divide(make(2L << b - 1));
|
|
|
|
Random rand = new Random();
|
|
while (certainty-- > 0)
|
|
{
|
|
// Pick a random number greater than 1 and less than this.
|
|
// The algorithm says to pick a small number to make the calculations
|
|
// go faster, but it doesn't say how small; we'll use 2 to 1024.
|
|
int a = rand.nextInt();
|
|
a = (a < 0 ? -a : a) % 1023 + 2;
|
|
|
|
BigInteger z = make(a).modPow(m, this);
|
|
if (z.isOne() || z.equals(pMinus1))
|
|
continue; // Passes the test; may be prime.
|
|
|
|
int i;
|
|
for (i = 0; i < b; )
|
|
{
|
|
if (z.isOne())
|
|
return false;
|
|
i++;
|
|
if (z.equals(pMinus1))
|
|
break; // Passes the test; may be prime.
|
|
|
|
z = z.modPow(make(2), this);
|
|
}
|
|
|
|
if (i == b && !z.equals(pMinus1))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
private void setInvert()
|
|
{
|
|
if (words == null)
|
|
ival = ~ival;
|
|
else
|
|
{
|
|
for (int i = ival; --i >= 0; )
|
|
words[i] = ~words[i];
|
|
}
|
|
}
|
|
|
|
private void setShiftLeft(BigInteger x, int count)
|
|
{
|
|
int[] xwords;
|
|
int xlen;
|
|
if (x.words == null)
|
|
{
|
|
if (count < 32)
|
|
{
|
|
set((long) x.ival << count);
|
|
return;
|
|
}
|
|
xwords = new int[1];
|
|
xwords[0] = x.ival;
|
|
xlen = 1;
|
|
}
|
|
else
|
|
{
|
|
xwords = x.words;
|
|
xlen = x.ival;
|
|
}
|
|
int word_count = count >> 5;
|
|
count &= 31;
|
|
int new_len = xlen + word_count;
|
|
if (count == 0)
|
|
{
|
|
realloc(new_len);
|
|
for (int i = xlen; --i >= 0; )
|
|
words[i+word_count] = xwords[i];
|
|
}
|
|
else
|
|
{
|
|
new_len++;
|
|
realloc(new_len);
|
|
int shift_out = MPN.lshift(words, word_count, xwords, xlen, count);
|
|
count = 32 - count;
|
|
words[new_len-1] = (shift_out << count) >> count; // sign-extend.
|
|
}
|
|
ival = new_len;
|
|
for (int i = word_count; --i >= 0; )
|
|
words[i] = 0;
|
|
}
|
|
|
|
private void setShiftRight(BigInteger x, int count)
|
|
{
|
|
if (x.words == null)
|
|
set(count < 32 ? x.ival >> count : x.ival < 0 ? -1 : 0);
|
|
else if (count == 0)
|
|
set(x);
|
|
else
|
|
{
|
|
boolean neg = x.isNegative();
|
|
int word_count = count >> 5;
|
|
count &= 31;
|
|
int d_len = x.ival - word_count;
|
|
if (d_len <= 0)
|
|
set(neg ? -1 : 0);
|
|
else
|
|
{
|
|
if (words == null || words.length < d_len)
|
|
realloc(d_len);
|
|
if (count == 0)
|
|
System.arraycopy(x.words, word_count, words, 0, d_len);
|
|
else
|
|
{
|
|
MPN.rshift(words, x.words, word_count, d_len, count);
|
|
if (neg)
|
|
words[d_len-1] |= -1 << (32 - count);
|
|
}
|
|
ival = d_len;
|
|
}
|
|
}
|
|
}
|
|
|
|
private void setShift(BigInteger x, int count)
|
|
{
|
|
if (count > 0)
|
|
setShiftLeft(x, count);
|
|
else
|
|
setShiftRight(x, -count);
|
|
}
|
|
|
|
private static BigInteger shift(BigInteger x, int count)
|
|
{
|
|
if (x.words == null)
|
|
{
|
|
if (count <= 0)
|
|
return make(count > -32 ? x.ival >> (-count) : x.ival < 0 ? -1 : 0);
|
|
if (count < 32)
|
|
return make((long) x.ival << count);
|
|
}
|
|
if (count == 0)
|
|
return x;
|
|
BigInteger result = new BigInteger(0);
|
|
result.setShift(x, count);
|
|
return result.canonicalize();
|
|
}
|
|
|
|
public BigInteger shiftLeft(int n)
|
|
{
|
|
return shift(this, n);
|
|
}
|
|
|
|
public BigInteger shiftRight(int n)
|
|
{
|
|
return shift(this, -n);
|
|
}
|
|
|
|
private void format(int radix, StringBuffer buffer)
|
|
{
|
|
if (words == null)
|
|
buffer.append(Integer.toString(ival, radix));
|
|
else if (ival <= 2)
|
|
buffer.append(Long.toString(longValue(), radix));
|
|
else
|
|
{
|
|
boolean neg = isNegative();
|
|
int[] work;
|
|
if (neg || radix != 16)
|
|
{
|
|
work = new int[ival];
|
|
getAbsolute(work);
|
|
}
|
|
else
|
|
work = words;
|
|
int len = ival;
|
|
|
|
int buf_size = len * (MPN.chars_per_word(radix) + 1);
|
|
if (radix == 16)
|
|
{
|
|
if (neg)
|
|
buffer.append('-');
|
|
int buf_start = buffer.length();
|
|
for (int i = len; --i >= 0; )
|
|
{
|
|
int word = work[i];
|
|
for (int j = 8; --j >= 0; )
|
|
{
|
|
int hex_digit = (word >> (4 * j)) & 0xF;
|
|
// Suppress leading zeros:
|
|
if (hex_digit > 0 || buffer.length() > buf_start)
|
|
buffer.append(Character.forDigit(hex_digit, 16));
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
int i = buffer.length();
|
|
for (;;)
|
|
{
|
|
int digit = MPN.divmod_1(work, work, len, radix);
|
|
buffer.append(Character.forDigit(digit, radix));
|
|
while (len > 0 && work[len-1] == 0) len--;
|
|
if (len == 0)
|
|
break;
|
|
}
|
|
if (neg)
|
|
buffer.append('-');
|
|
/* Reverse buffer. */
|
|
int j = buffer.length() - 1;
|
|
while (i < j)
|
|
{
|
|
char tmp = buffer.charAt(i);
|
|
buffer.setCharAt(i, buffer.charAt(j));
|
|
buffer.setCharAt(j, tmp);
|
|
i++; j--;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
public String toString()
|
|
{
|
|
return toString(10);
|
|
}
|
|
|
|
public String toString(int radix)
|
|
{
|
|
if (words == null)
|
|
return Integer.toString(ival, radix);
|
|
else if (ival <= 2)
|
|
return Long.toString(longValue(), radix);
|
|
int buf_size = ival * (MPN.chars_per_word(radix) + 1);
|
|
StringBuffer buffer = new StringBuffer(buf_size);
|
|
format(radix, buffer);
|
|
return buffer.toString();
|
|
}
|
|
|
|
public int intValue()
|
|
{
|
|
if (words == null)
|
|
return ival;
|
|
return words[0];
|
|
}
|
|
|
|
public long longValue()
|
|
{
|
|
if (words == null)
|
|
return ival;
|
|
if (ival == 1)
|
|
return words[0];
|
|
return ((long)words[1] << 32) + ((long)words[0] & 0xffffffffL);
|
|
}
|
|
|
|
public int hashCode()
|
|
{
|
|
// FIXME: May not match hashcode of JDK.
|
|
return words == null ? ival : (words[0] + words[ival - 1]);
|
|
}
|
|
|
|
/* Assumes x and y are both canonicalized. */
|
|
private static boolean equals(BigInteger x, BigInteger y)
|
|
{
|
|
if (x.words == null && y.words == null)
|
|
return x.ival == y.ival;
|
|
if (x.words == null || y.words == null || x.ival != y.ival)
|
|
return false;
|
|
for (int i = x.ival; --i >= 0; )
|
|
{
|
|
if (x.words[i] != y.words[i])
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/* Assumes this and obj are both canonicalized. */
|
|
public boolean equals(Object obj)
|
|
{
|
|
if (obj == null || ! (obj instanceof BigInteger))
|
|
return false;
|
|
return BigInteger.equals(this, (BigInteger) obj);
|
|
}
|
|
|
|
private static BigInteger valueOf(String s, int radix)
|
|
throws NumberFormatException
|
|
{
|
|
int len = s.length();
|
|
// Testing (len < MPN.chars_per_word(radix)) would be more accurate,
|
|
// but slightly more expensive, for little practical gain.
|
|
if (len <= 15 && radix <= 16)
|
|
return BigInteger.make(Long.parseLong(s, radix));
|
|
|
|
int byte_len = 0;
|
|
byte[] bytes = new byte[len];
|
|
boolean negative = false;
|
|
for (int i = 0; i < len; i++)
|
|
{
|
|
char ch = s.charAt(i);
|
|
if (ch == '-')
|
|
negative = true;
|
|
else if (ch == '_' || (byte_len == 0 && (ch == ' ' || ch == '\t')))
|
|
continue;
|
|
else
|
|
{
|
|
int digit = Character.digit(ch, radix);
|
|
if (digit < 0)
|
|
break;
|
|
bytes[byte_len++] = (byte) digit;
|
|
}
|
|
}
|
|
return valueOf(bytes, byte_len, negative, radix);
|
|
}
|
|
|
|
private static BigInteger valueOf(byte[] digits, int byte_len,
|
|
boolean negative, int radix)
|
|
{
|
|
int chars_per_word = MPN.chars_per_word(radix);
|
|
int[] words = new int[byte_len / chars_per_word + 1];
|
|
int size = MPN.set_str(words, digits, byte_len, radix);
|
|
if (size == 0)
|
|
return ZERO;
|
|
if (words[size-1] < 0)
|
|
words[size++] = 0;
|
|
if (negative)
|
|
negate(words, words, size);
|
|
return make(words, size);
|
|
}
|
|
|
|
public double doubleValue()
|
|
{
|
|
if (words == null)
|
|
return (double) ival;
|
|
if (ival <= 2)
|
|
return (double) longValue();
|
|
if (isNegative())
|
|
return BigInteger.neg(this).roundToDouble(0, true, false);
|
|
else
|
|
return roundToDouble(0, false, false);
|
|
}
|
|
|
|
public float floatValue()
|
|
{
|
|
return (float) doubleValue();
|
|
}
|
|
|
|
/** Return true if any of the lowest n bits are one.
|
|
* (false if n is negative). */
|
|
private boolean checkBits(int n)
|
|
{
|
|
if (n <= 0)
|
|
return false;
|
|
if (words == null)
|
|
return n > 31 || ((ival & ((1 << n) - 1)) != 0);
|
|
int i;
|
|
for (i = 0; i < (n >> 5) ; i++)
|
|
if (words[i] != 0)
|
|
return true;
|
|
return (n & 31) != 0 && (words[i] & ((1 << (n & 31)) - 1)) != 0;
|
|
}
|
|
|
|
/** Convert a semi-processed BigInteger to double.
|
|
* Number must be non-negative. Multiplies by a power of two, applies sign,
|
|
* and converts to double, with the usual java rounding.
|
|
* @param exp power of two, positive or negative, by which to multiply
|
|
* @param neg true if negative
|
|
* @param remainder true if the BigInteger is the result of a truncating
|
|
* division that had non-zero remainder. To ensure proper rounding in
|
|
* this case, the BigInteger must have at least 54 bits. */
|
|
private double roundToDouble(int exp, boolean neg, boolean remainder)
|
|
{
|
|
// Compute length.
|
|
int il = bitLength();
|
|
|
|
// Exponent when normalized to have decimal point directly after
|
|
// leading one. This is stored excess 1023 in the exponent bit field.
|
|
exp += il - 1;
|
|
|
|
// Gross underflow. If exp == -1075, we let the rounding
|
|
// computation determine whether it is minval or 0 (which are just
|
|
// 0x0000 0000 0000 0001 and 0x0000 0000 0000 0000 as bit
|
|
// patterns).
|
|
if (exp < -1075)
|
|
return neg ? -0.0 : 0.0;
|
|
|
|
// gross overflow
|
|
if (exp > 1023)
|
|
return neg ? Double.NEGATIVE_INFINITY : Double.POSITIVE_INFINITY;
|
|
|
|
// number of bits in mantissa, including the leading one.
|
|
// 53 unless it's denormalized
|
|
int ml = (exp >= -1022 ? 53 : 53 + exp + 1022);
|
|
|
|
// Get top ml + 1 bits. The extra one is for rounding.
|
|
long m;
|
|
int excess_bits = il - (ml + 1);
|
|
if (excess_bits > 0)
|
|
m = ((words == null) ? ival >> excess_bits
|
|
: MPN.rshift_long(words, ival, excess_bits));
|
|
else
|
|
m = longValue() << (- excess_bits);
|
|
|
|
// Special rounding for maxval. If the number exceeds maxval by
|
|
// any amount, even if it's less than half a step, it overflows.
|
|
if (exp == 1023 && ((m >> 1) == (1L << 53) - 1))
|
|
{
|
|
if (remainder || checkBits(il - ml))
|
|
return neg ? Double.NEGATIVE_INFINITY : Double.POSITIVE_INFINITY;
|
|
else
|
|
return neg ? - Double.MAX_VALUE : Double.MAX_VALUE;
|
|
}
|
|
|
|
// Normal round-to-even rule: round up if the bit dropped is a one, and
|
|
// the bit above it or any of the bits below it is a one.
|
|
if ((m & 1) == 1
|
|
&& ((m & 2) == 2 || remainder || checkBits(excess_bits)))
|
|
{
|
|
m += 2;
|
|
// Check if we overflowed the mantissa
|
|
if ((m & (1L << 54)) != 0)
|
|
{
|
|
exp++;
|
|
// renormalize
|
|
m >>= 1;
|
|
}
|
|
// Check if a denormalized mantissa was just rounded up to a
|
|
// normalized one.
|
|
else if (ml == 52 && (m & (1L << 53)) != 0)
|
|
exp++;
|
|
}
|
|
|
|
// Discard the rounding bit
|
|
m >>= 1;
|
|
|
|
long bits_sign = neg ? (1L << 63) : 0;
|
|
exp += 1023;
|
|
long bits_exp = (exp <= 0) ? 0 : ((long)exp) << 52;
|
|
long bits_mant = m & ~(1L << 52);
|
|
return Double.longBitsToDouble(bits_sign | bits_exp | bits_mant);
|
|
}
|
|
|
|
/** Copy the abolute value of this into an array of words.
|
|
* Assumes words.length >= (this.words == null ? 1 : this.ival).
|
|
* Result is zero-extended, but need not be a valid 2's complement number.
|
|
*/
|
|
|
|
private void getAbsolute(int[] words)
|
|
{
|
|
int len;
|
|
if (this.words == null)
|
|
{
|
|
len = 1;
|
|
words[0] = this.ival;
|
|
}
|
|
else
|
|
{
|
|
len = this.ival;
|
|
for (int i = len; --i >= 0; )
|
|
words[i] = this.words[i];
|
|
}
|
|
if (words[len - 1] < 0)
|
|
negate(words, words, len);
|
|
for (int i = words.length; --i > len; )
|
|
words[i] = 0;
|
|
}
|
|
|
|
/** Set dest[0:len-1] to the negation of src[0:len-1].
|
|
* Return true if overflow (i.e. if src is -2**(32*len-1)).
|
|
* Ok for src==dest. */
|
|
private static boolean negate(int[] dest, int[] src, int len)
|
|
{
|
|
long carry = 1;
|
|
boolean negative = src[len-1] < 0;
|
|
for (int i = 0; i < len; i++)
|
|
{
|
|
carry += ((long) (~src[i]) & 0xffffffffL);
|
|
dest[i] = (int) carry;
|
|
carry >>= 32;
|
|
}
|
|
return (negative && dest[len-1] < 0);
|
|
}
|
|
|
|
/** Destructively set this to the negative of x.
|
|
* It is OK if x==this.*/
|
|
private void setNegative(BigInteger x)
|
|
{
|
|
int len = x.ival;
|
|
if (x.words == null)
|
|
{
|
|
if (len == Integer.MIN_VALUE)
|
|
set(- (long) len);
|
|
else
|
|
set(-len);
|
|
return;
|
|
}
|
|
realloc(len + 1);
|
|
if (BigInteger.negate(words, x.words, len))
|
|
words[len++] = 0;
|
|
ival = len;
|
|
}
|
|
|
|
/** Destructively negate this. */
|
|
private final void setNegative()
|
|
{
|
|
setNegative(this);
|
|
}
|
|
|
|
private static BigInteger abs(BigInteger x)
|
|
{
|
|
return x.isNegative() ? neg(x) : x;
|
|
}
|
|
|
|
public BigInteger abs()
|
|
{
|
|
return abs(this);
|
|
}
|
|
|
|
private static BigInteger neg(BigInteger x)
|
|
{
|
|
if (x.words == null && x.ival != Integer.MIN_VALUE)
|
|
return make(- x.ival);
|
|
BigInteger result = new BigInteger(0);
|
|
result.setNegative(x);
|
|
return result.canonicalize();
|
|
}
|
|
|
|
public BigInteger negate()
|
|
{
|
|
return BigInteger.neg(this);
|
|
}
|
|
|
|
/** Calculates ceiling(log2(this < 0 ? -this : this+1))
|
|
* See Common Lisp: the Language, 2nd ed, p. 361.
|
|
*/
|
|
public int bitLength()
|
|
{
|
|
if (words == null)
|
|
return MPN.intLength(ival);
|
|
else
|
|
return MPN.intLength(words, ival);
|
|
}
|
|
|
|
public byte[] toByteArray()
|
|
{
|
|
// Determine number of bytes needed. The method bitlength returns
|
|
// the size without the sign bit, so add one bit for that and then
|
|
// add 7 more to emulate the ceil function using integer math.
|
|
byte[] bytes = new byte[(bitLength() + 1 + 7) / 8];
|
|
int nbytes = bytes.length;
|
|
|
|
int wptr = 0;
|
|
int word;
|
|
|
|
// Deal with words array until one word or less is left to process.
|
|
// If BigInteger is an int, then it is in ival and nbytes will be <= 4.
|
|
while (nbytes > 4)
|
|
{
|
|
word = words[wptr++];
|
|
for (int i = 4; i > 0; --i, word >>= 8)
|
|
bytes[--nbytes] = (byte) word;
|
|
}
|
|
|
|
// Deal with the last few bytes. If BigInteger is an int, use ival.
|
|
word = (words == null) ? ival : words[wptr];
|
|
for ( ; nbytes > 0; word >>= 8)
|
|
bytes[--nbytes] = (byte) word;
|
|
|
|
return bytes;
|
|
}
|
|
|
|
/** Return the boolean opcode (for bitOp) for swapped operands.
|
|
* I.e. bitOp(swappedOp(op), x, y) == bitOp(op, y, x).
|
|
*/
|
|
private static int swappedOp(int op)
|
|
{
|
|
return
|
|
"\000\001\004\005\002\003\006\007\010\011\014\015\012\013\016\017"
|
|
.charAt(op);
|
|
}
|
|
|
|
/** Do one the the 16 possible bit-wise operations of two BigIntegers. */
|
|
private static BigInteger bitOp(int op, BigInteger x, BigInteger y)
|
|
{
|
|
switch (op)
|
|
{
|
|
case 0: return ZERO;
|
|
case 1: return x.and(y);
|
|
case 3: return x;
|
|
case 5: return y;
|
|
case 15: return make(-1);
|
|
}
|
|
BigInteger result = new BigInteger();
|
|
setBitOp(result, op, x, y);
|
|
return result.canonicalize();
|
|
}
|
|
|
|
/** Do one the the 16 possible bit-wise operations of two BigIntegers. */
|
|
private static void setBitOp(BigInteger result, int op,
|
|
BigInteger x, BigInteger y)
|
|
{
|
|
if (y.words == null) ;
|
|
else if (x.words == null || x.ival < y.ival)
|
|
{
|
|
BigInteger temp = x; x = y; y = temp;
|
|
op = swappedOp(op);
|
|
}
|
|
int xi;
|
|
int yi;
|
|
int xlen, ylen;
|
|
if (y.words == null)
|
|
{
|
|
yi = y.ival;
|
|
ylen = 1;
|
|
}
|
|
else
|
|
{
|
|
yi = y.words[0];
|
|
ylen = y.ival;
|
|
}
|
|
if (x.words == null)
|
|
{
|
|
xi = x.ival;
|
|
xlen = 1;
|
|
}
|
|
else
|
|
{
|
|
xi = x.words[0];
|
|
xlen = x.ival;
|
|
}
|
|
if (xlen > 1)
|
|
result.realloc(xlen);
|
|
int[] w = result.words;
|
|
int i = 0;
|
|
// Code for how to handle the remainder of x.
|
|
// 0: Truncate to length of y.
|
|
// 1: Copy rest of x.
|
|
// 2: Invert rest of x.
|
|
int finish = 0;
|
|
int ni;
|
|
switch (op)
|
|
{
|
|
case 0: // clr
|
|
ni = 0;
|
|
break;
|
|
case 1: // and
|
|
for (;;)
|
|
{
|
|
ni = xi & yi;
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
if (yi < 0) finish = 1;
|
|
break;
|
|
case 2: // andc2
|
|
for (;;)
|
|
{
|
|
ni = xi & ~yi;
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
if (yi >= 0) finish = 1;
|
|
break;
|
|
case 3: // copy x
|
|
ni = xi;
|
|
finish = 1; // Copy rest
|
|
break;
|
|
case 4: // andc1
|
|
for (;;)
|
|
{
|
|
ni = ~xi & yi;
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
if (yi < 0) finish = 2;
|
|
break;
|
|
case 5: // copy y
|
|
for (;;)
|
|
{
|
|
ni = yi;
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
break;
|
|
case 6: // xor
|
|
for (;;)
|
|
{
|
|
ni = xi ^ yi;
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
finish = yi < 0 ? 2 : 1;
|
|
break;
|
|
case 7: // ior
|
|
for (;;)
|
|
{
|
|
ni = xi | yi;
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
if (yi >= 0) finish = 1;
|
|
break;
|
|
case 8: // nor
|
|
for (;;)
|
|
{
|
|
ni = ~(xi | yi);
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
if (yi >= 0) finish = 2;
|
|
break;
|
|
case 9: // eqv [exclusive nor]
|
|
for (;;)
|
|
{
|
|
ni = ~(xi ^ yi);
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
finish = yi >= 0 ? 2 : 1;
|
|
break;
|
|
case 10: // c2
|
|
for (;;)
|
|
{
|
|
ni = ~yi;
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
break;
|
|
case 11: // orc2
|
|
for (;;)
|
|
{
|
|
ni = xi | ~yi;
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
if (yi < 0) finish = 1;
|
|
break;
|
|
case 12: // c1
|
|
ni = ~xi;
|
|
finish = 2;
|
|
break;
|
|
case 13: // orc1
|
|
for (;;)
|
|
{
|
|
ni = ~xi | yi;
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
if (yi >= 0) finish = 2;
|
|
break;
|
|
case 14: // nand
|
|
for (;;)
|
|
{
|
|
ni = ~(xi & yi);
|
|
if (i+1 >= ylen) break;
|
|
w[i++] = ni; xi = x.words[i]; yi = y.words[i];
|
|
}
|
|
if (yi < 0) finish = 2;
|
|
break;
|
|
default:
|
|
case 15: // set
|
|
ni = -1;
|
|
break;
|
|
}
|
|
// Here i==ylen-1; w[0]..w[i-1] have the correct result;
|
|
// and ni contains the correct result for w[i+1].
|
|
if (i+1 == xlen)
|
|
finish = 0;
|
|
switch (finish)
|
|
{
|
|
case 0:
|
|
if (i == 0 && w == null)
|
|
{
|
|
result.ival = ni;
|
|
return;
|
|
}
|
|
w[i++] = ni;
|
|
break;
|
|
case 1: w[i] = ni; while (++i < xlen) w[i] = x.words[i]; break;
|
|
case 2: w[i] = ni; while (++i < xlen) w[i] = ~x.words[i]; break;
|
|
}
|
|
result.ival = i;
|
|
}
|
|
|
|
/** Return the logical (bit-wise) "and" of a BigInteger and an int. */
|
|
private static BigInteger and(BigInteger x, int y)
|
|
{
|
|
if (x.words == null)
|
|
return BigInteger.make(x.ival & y);
|
|
if (y >= 0)
|
|
return BigInteger.make(x.words[0] & y);
|
|
int len = x.ival;
|
|
int[] words = new int[len];
|
|
words[0] = x.words[0] & y;
|
|
while (--len > 0)
|
|
words[len] = x.words[len];
|
|
return BigInteger.make(words, x.ival);
|
|
}
|
|
|
|
/** Return the logical (bit-wise) "and" of two BigIntegers. */
|
|
public BigInteger and(BigInteger y)
|
|
{
|
|
if (y.words == null)
|
|
return and(this, y.ival);
|
|
else if (words == null)
|
|
return and(y, ival);
|
|
|
|
BigInteger x = this;
|
|
if (ival < y.ival)
|
|
{
|
|
BigInteger temp = this; x = y; y = temp;
|
|
}
|
|
int i;
|
|
int len = y.isNegative() ? x.ival : y.ival;
|
|
int[] words = new int[len];
|
|
for (i = 0; i < y.ival; i++)
|
|
words[i] = x.words[i] & y.words[i];
|
|
for ( ; i < len; i++)
|
|
words[i] = x.words[i];
|
|
return BigInteger.make(words, len);
|
|
}
|
|
|
|
/** Return the logical (bit-wise) "(inclusive) or" of two BigIntegers. */
|
|
public BigInteger or(BigInteger y)
|
|
{
|
|
return bitOp(7, this, y);
|
|
}
|
|
|
|
/** Return the logical (bit-wise) "exclusive or" of two BigIntegers. */
|
|
public BigInteger xor(BigInteger y)
|
|
{
|
|
return bitOp(6, this, y);
|
|
}
|
|
|
|
/** Return the logical (bit-wise) negation of a BigInteger. */
|
|
public BigInteger not()
|
|
{
|
|
return bitOp(12, this, ZERO);
|
|
}
|
|
|
|
public BigInteger andNot(BigInteger val)
|
|
{
|
|
return and(val.not());
|
|
}
|
|
|
|
public BigInteger clearBit(int n)
|
|
{
|
|
if (n < 0)
|
|
throw new ArithmeticException();
|
|
|
|
return and(ONE.shiftLeft(n).not());
|
|
}
|
|
|
|
public BigInteger setBit(int n)
|
|
{
|
|
if (n < 0)
|
|
throw new ArithmeticException();
|
|
|
|
return or(ONE.shiftLeft(n));
|
|
}
|
|
|
|
public boolean testBit(int n)
|
|
{
|
|
if (n < 0)
|
|
throw new ArithmeticException();
|
|
|
|
return !and(ONE.shiftLeft(n)).isZero();
|
|
}
|
|
|
|
public BigInteger flipBit(int n)
|
|
{
|
|
if (n < 0)
|
|
throw new ArithmeticException();
|
|
|
|
return xor(ONE.shiftLeft(n));
|
|
}
|
|
|
|
public int getLowestSetBit()
|
|
{
|
|
if (isZero())
|
|
return -1;
|
|
|
|
if (words == null)
|
|
return MPN.findLowestBit(ival);
|
|
else
|
|
return MPN.findLowestBit(words);
|
|
}
|
|
|
|
// bit4count[I] is number of '1' bits in I.
|
|
private static final byte[] bit4_count = { 0, 1, 1, 2, 1, 2, 2, 3,
|
|
1, 2, 2, 3, 2, 3, 3, 4};
|
|
|
|
private static int bitCount(int i)
|
|
{
|
|
int count = 0;
|
|
while (i != 0)
|
|
{
|
|
count += bit4_count[i & 15];
|
|
i >>>= 4;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
private static int bitCount(int[] x, int len)
|
|
{
|
|
int count = 0;
|
|
while (--len >= 0)
|
|
count += bitCount(x[len]);
|
|
return count;
|
|
}
|
|
|
|
/** Count one bits in a BigInteger.
|
|
* If argument is negative, count zero bits instead. */
|
|
public int bitCount()
|
|
{
|
|
int i, x_len;
|
|
int[] x_words = words;
|
|
if (x_words == null)
|
|
{
|
|
x_len = 1;
|
|
i = bitCount(ival);
|
|
}
|
|
else
|
|
{
|
|
x_len = ival;
|
|
i = bitCount(x_words, x_len);
|
|
}
|
|
return isNegative() ? x_len * 32 - i : i;
|
|
}
|
|
|
|
private void readObject(ObjectInputStream s)
|
|
throws IOException, ClassNotFoundException
|
|
{
|
|
s.defaultReadObject();
|
|
words = byteArrayToIntArray(magnitude, signum < 0 ? -1 : 0);
|
|
BigInteger result = make(words, words.length);
|
|
this.ival = result.ival;
|
|
this.words = result.words;
|
|
}
|
|
|
|
private void writeObject(ObjectOutputStream s)
|
|
throws IOException, ClassNotFoundException
|
|
{
|
|
signum = signum();
|
|
magnitude = toByteArray();
|
|
s.defaultWriteObject();
|
|
}
|
|
}
|