| 0,0 → 1,123 |
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| package de.viathinksoft.immortable.gen2; |
| |
| import java.math.BigInteger; |
| |
| import de.viathinksoft.immortable.gen2.math.CoPrimeExpectedException; |
| import de.viathinksoft.immortable.gen2.math.ImmortableBase; |
| import de.viathinksoft.immortable.gen2.math.MathUtils; |
| import de.viathinksoft.immortable.gen2.math.MathUtils2; |
| |
| /** |
| * Immortable Number Generator (ING) |
| * |
| * @author Daniel Marschall |
| */ |
| |
| public class Immortable { |
| |
| /** |
| * Calculates M5 or M6 |
| * |
| * @param base |
| * @param u |
| * @return |
| */ |
| public static BigInteger M(ImmortableBase base, BigInteger u) { |
| BigInteger p, q; |
| |
| if (base == ImmortableBase.M5) { |
| p = BigInteger.ONE; |
| q = BigInteger.ZERO; |
| } else if (base == ImmortableBase.M6) { |
| p = BigInteger.ZERO; |
| q = BigInteger.ONE; |
| } else { |
| p = null; |
| q = null; |
| } |
| |
| BigInteger a = MathUtils2.pow(new BigInteger("2"), u); |
| BigInteger b = MathUtils2.pow(new BigInteger("5"), u); |
| |
| // To calculate M5: |
| // x = 2^u = a mod 1 |
| // x = 5^u = b mod 0 |
| |
| // To calculate M6: |
| // x = 2^u = a mod 0 |
| // x = 5^u = b mod 1 |
| |
| try { |
| return MathUtils.chineseRemainder(p, a, q, b); |
| } catch (CoPrimeExpectedException e) { |
| // Can never happen since 2^u and 5^u are always coprimes. |
| return null; |
| } |
| } |
| |
| /** |
| * Gets M5(u) |
| * |
| * @param u |
| * Length of number |
| * @return |
| */ |
| public static BigInteger M5(BigInteger u) { |
| return M(ImmortableBase.M5, u); |
| } |
| |
| /** |
| * Gets M6(u) |
| * |
| * @param u |
| * Length of number |
| * @return |
| */ |
| public static BigInteger M6(BigInteger u) { |
| return M(ImmortableBase.M6, u); |
| } |
| |
| /** |
| * Toggles between M5 and M6 base. |
| * |
| * @param cur |
| * Number |
| * @param u |
| * Length of number (because of possible leading zeros) |
| * @return Number in opposide base. |
| * @throws InvalidLengthException |
| */ |
| public static BigInteger toggleBase(BigInteger cur, BigInteger u) |
| throws InvalidLengthException { |
| // Converts M6(u) <-> M5(u) |
| // M6(u) = 1 + 10^u - M5(u) |
| // M5(u) = 1 + 10^u - M6(u) |
| |
| if (u.compareTo(MathUtils2.length(cur)) < 0) { |
| throw new InvalidLengthException(); |
| } |
| |
| return BigInteger.ONE.add(MathUtils2.pow(BigInteger.TEN, u)).subtract(cur); |
| } |
| |
| /** |
| * Toggles between M5 and M6 base. The length of the current number is |
| * assumed (and no leading zero). |
| * |
| * @param cur |
| * @return |
| */ |
| public static BigInteger toggleBase(BigInteger cur) { |
| try { |
| return toggleBase(cur, MathUtils2.length(cur)); |
| } catch (InvalidLengthException e) { |
| // Should never happen |
| return null; |
| } |
| |
| } |
| |
| private Immortable() { |
| } |
| |
| } |
| Property changes: |
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| Added: svn:mime-type |
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| +text/plain |
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| \ No newline at end of property |
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