80 lines
2.2 KiB
Java
80 lines
2.2 KiB
Java
// SPDX-FileCopyrightText: 2018 Paul Schaub <vanitasvitae@fsfe.org>
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//
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// SPDX-License-Identifier: Apache-2.0
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package org.pgpainless.algorithm;
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import java.util.Map;
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import java.util.NoSuchElementException;
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import java.util.concurrent.ConcurrentHashMap;
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import org.bouncycastle.bcpg.CompressionAlgorithmTags;
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import javax.annotation.Nonnull;
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import javax.annotation.Nullable;
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/**
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* Enumeration of possible compression algorithms.
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*
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* @see <a href="https://tools.ietf.org/html/rfc4880#section-9.3">RFC4880: Compression Algorithm Tags</a>
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*/
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public enum CompressionAlgorithm {
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UNCOMPRESSED (CompressionAlgorithmTags.UNCOMPRESSED),
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ZIP (CompressionAlgorithmTags.ZIP),
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ZLIB (CompressionAlgorithmTags.ZLIB),
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BZIP2 (CompressionAlgorithmTags.BZIP2),
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;
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private static final Map<Integer, CompressionAlgorithm> MAP = new ConcurrentHashMap<>();
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static {
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for (CompressionAlgorithm c : CompressionAlgorithm.values()) {
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MAP.put(c.algorithmId, c);
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}
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}
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/**
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* Return the {@link CompressionAlgorithm} value that corresponds to the provided numerical id.
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* If an invalid id is provided, null is returned.
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*
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* @param id id
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* @return compression algorithm
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*/
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@Nullable
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public static CompressionAlgorithm fromId(int id) {
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return MAP.get(id);
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}
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/**
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* Return the {@link CompressionAlgorithm} value that corresponds to the provided numerical id.
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* If an invalid id is provided, thrown an {@link NoSuchElementException}.
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*
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* @param id id
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* @return compression algorithm
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* @throws NoSuchElementException in case of an unmapped id
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*/
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@Nonnull
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public static CompressionAlgorithm requireFromId(int id) {
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CompressionAlgorithm algorithm = fromId(id);
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if (algorithm == null) {
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throw new NoSuchElementException("No CompressionAlgorithm found for id " + id);
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}
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return algorithm;
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}
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private final int algorithmId;
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CompressionAlgorithm(int id) {
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this.algorithmId = id;
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}
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/**
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* Return the numerical algorithm tag corresponding to this compression algorithm.
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* @return id
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*/
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public int getAlgorithmId() {
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return algorithmId;
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}
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}
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