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/* |
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* This file is part of ArakneUtils. |
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* |
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* ArakneUtils is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU Lesser General Public License as published by |
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* the Free Software Foundation, either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* ArakneUtils is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public License |
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* along with ArakneUtils. If not, see <https://www.gnu.org/licenses/>. |
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* |
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* Copyright (c) 2017-2020 Vincent Quatrevieux |
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*/ |
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package fr.arakne.utils.encoding; |
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import org.checkerframework.checker.index.qual.NonNegative; |
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import org.checkerframework.common.value.qual.IntRange; |
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import org.checkerframework.dataflow.qual.Pure; |
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import org.checkerframework.dataflow.qual.SideEffectFree; |
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/** |
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* Implementation of the Dofus network checksum |
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* |
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* https://github.com/Emudofus/Dofus/blob/1.29/dofus/aks/Aks.as#L248 |
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*/ |
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public final class Checksum { |
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/** |
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* Utility class : disable constructor |
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*/ |
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private Checksum() {} |
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/** |
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* Compute the checksum as integer |
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* The returned value is in interval [0-16] |
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* |
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* @param value Value to compute |
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* |
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* @return The checksum of value |
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*/ |
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@Pure |
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@SuppressWarnings("compound.assignment") // chatAt cannot be negative |
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public static @IntRange(from = 0, to = 15) int integer(String value) { |
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1 |
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@NonNegative int checksum = 0; |
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for (int i = 0; i < value.length(); ++i) { |
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checksum += value.charAt(i) % 16; |
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} |
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return checksum % 16; |
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} |
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/** |
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* Compute the checksum as hexadecimal string |
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* The return value is a single hexadecimal char string |
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* |
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* @param value Value to compute |
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* |
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* @return The checksum of value |
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*/ |
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@SideEffectFree |
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public static String hexadecimal(String value) { |
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return Integer.toHexString(integer(value)).toUpperCase(); |
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} |
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/** |
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* Verify the checksum of the input value |
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* |
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* @param input The input value to check |
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* @param expectedChecksum The expected checksum as int |
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* |
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* @return true if checksum match |
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*/ |
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@Pure |
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public static boolean verify(String input, int expectedChecksum) { |
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1 |
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return integer(input) == expectedChecksum; |
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} |
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/** |
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* Verify the checksum of the input value |
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* |
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* @param input The input value to check |
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* @param expectedChecksum The expected checksum as hexadecimal string |
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* |
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* @return true if checksum match |
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*/ |
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@Pure |
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public static boolean verify(String input, String expectedChecksum) { |
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1 |
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return integer(input) == Integer.parseInt(expectedChecksum, 16); |
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} |
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} |
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Arakne /
ArakneUtils
