LongObjectId.java

  1. /*
  2.  * Copyright (C) 2015, Matthias Sohn <matthias.sohn@sap.com> and others
  3.  *
  4.  * This program and the accompanying materials are made available under the
  5.  * terms of the Eclipse Distribution License v. 1.0 which is available at
  6.  * https://www.eclipse.org/org/documents/edl-v10.php.
  7.  *
  8.  * SPDX-License-Identifier: BSD-3-Clause
  9.  */

  11. package org.eclipse.jgit.lfs.lib;

  13. import java.io.IOException;
  14. import java.io.ObjectInputStream;
  15. import java.io.ObjectOutputStream;
  16. import java.io.Serializable;

  18. import org.eclipse.jgit.lfs.errors.InvalidLongObjectIdException;
  19. import org.eclipse.jgit.util.NB;
  20. import org.eclipse.jgit.util.RawParseUtils;

  22. /**
  23.  * A SHA-256 abstraction.
  24.  *
  25.  * Ported to SHA-256 from {@link org.eclipse.jgit.lib.ObjectId}
  26.  *
  27.  * @since 4.3
  28.  */
  29. public class LongObjectId extends AnyLongObjectId implements Serializable {
  30.     private static final long serialVersionUID = 1L;

  32.     private static final LongObjectId ZEROID;

  34.     private static final String ZEROID_STR;

  36.     static {
  37.         ZEROID = new LongObjectId(0L, 0L, 0L, 0L);
  38.         ZEROID_STR = ZEROID.name();
  39.     }

  41.     /**
  42.      * Get the special all-zero LongObjectId.
  43.      *
  44.      * @return the all-zero LongObjectId, often used to stand-in for no object.
  45.      */
  46.     public static final LongObjectId zeroId() {
  47.         return ZEROID;
  48.     }

  50.     /**
  51.      * Test a string of characters to verify that it can be interpreted as
  52.      * LongObjectId.
  53.      * <p>
  54.      * If true the string can be parsed with {@link #fromString(String)}.
  55.      *
  56.      * @param id
  57.      *            the string to test.
  58.      * @return true if the string can converted into an LongObjectId.
  59.      */
  60.     public static final boolean isId(String id) {
  61.         if (id.length() != Constants.LONG_OBJECT_ID_STRING_LENGTH)
  62.             return false;
  63.         try {
  64.             for (int i = 0; i < Constants.LONG_OBJECT_ID_STRING_LENGTH; i++) {
  65.                 RawParseUtils.parseHexInt4((byte) id.charAt(i));
  66.             }
  67.             return true;
  68.         } catch (ArrayIndexOutOfBoundsException e) {
  69.             return false;
  70.         }
  71.     }

  73.     /**
  74.      * Convert a LongObjectId into a hex string representation.
  75.      *
  76.      * @param i
  77.      *            the id to convert. May be null.
  78.      * @return the hex string conversion of this id's content.
  79.      */
  80.     public static final String toString(LongObjectId i) {
  81.         return i != null ? i.name() : ZEROID_STR;
  82.     }

  84.     /**
  85.      * Compare two object identifier byte sequences for equality.
  86.      *
  87.      * @param firstBuffer
  88.      *            the first buffer to compare against. Must have at least 32
  89.      *            bytes from position fi through the end of the buffer.
  90.      * @param fi
  91.      *            first offset within firstBuffer to begin testing.
  92.      * @param secondBuffer
  93.      *            the second buffer to compare against. Must have at least 32
  94.      *            bytes from position si through the end of the buffer.
  95.      * @param si
  96.      *            first offset within secondBuffer to begin testing.
  97.      * @return true if the two identifiers are the same.
  98.      */
  99.     public static boolean equals(final byte[] firstBuffer, final int fi,
  100.             final byte[] secondBuffer, final int si) {
  101.         return firstBuffer[fi] == secondBuffer[si]
  102.                 && firstBuffer[fi + 1] == secondBuffer[si + 1]
  103.                 && firstBuffer[fi + 2] == secondBuffer[si + 2]
  104.                 && firstBuffer[fi + 3] == secondBuffer[si + 3]
  105.                 && firstBuffer[fi + 4] == secondBuffer[si + 4]
  106.                 && firstBuffer[fi + 5] == secondBuffer[si + 5]
  107.                 && firstBuffer[fi + 6] == secondBuffer[si + 6]
  108.                 && firstBuffer[fi + 7] == secondBuffer[si + 7]
  109.                 && firstBuffer[fi + 8] == secondBuffer[si + 8]
  110.                 && firstBuffer[fi + 9] == secondBuffer[si + 9]
  111.                 && firstBuffer[fi + 10] == secondBuffer[si + 10]
  112.                 && firstBuffer[fi + 11] == secondBuffer[si + 11]
  113.                 && firstBuffer[fi + 12] == secondBuffer[si + 12]
  114.                 && firstBuffer[fi + 13] == secondBuffer[si + 13]
  115.                 && firstBuffer[fi + 14] == secondBuffer[si + 14]
  116.                 && firstBuffer[fi + 15] == secondBuffer[si + 15]
  117.                 && firstBuffer[fi + 16] == secondBuffer[si + 16]
  118.                 && firstBuffer[fi + 17] == secondBuffer[si + 17]
  119.                 && firstBuffer[fi + 18] == secondBuffer[si + 18]
  120.                 && firstBuffer[fi + 19] == secondBuffer[si + 19]
  121.                 && firstBuffer[fi + 20] == secondBuffer[si + 20]
  122.                 && firstBuffer[fi + 21] == secondBuffer[si + 21]
  123.                 && firstBuffer[fi + 22] == secondBuffer[si + 22]
  124.                 && firstBuffer[fi + 23] == secondBuffer[si + 23]
  125.                 && firstBuffer[fi + 24] == secondBuffer[si + 24]
  126.                 && firstBuffer[fi + 25] == secondBuffer[si + 25]
  127.                 && firstBuffer[fi + 26] == secondBuffer[si + 26]
  128.                 && firstBuffer[fi + 27] == secondBuffer[si + 27]
  129.                 && firstBuffer[fi + 28] == secondBuffer[si + 28]
  130.                 && firstBuffer[fi + 29] == secondBuffer[si + 29]
  131.                 && firstBuffer[fi + 30] == secondBuffer[si + 30]
  132.                 && firstBuffer[fi + 31] == secondBuffer[si + 31];
  133.     }

  135.     /**
  136.      * Convert a LongObjectId from raw binary representation.
  137.      *
  138.      * @param bs
  139.      *            the raw byte buffer to read from. At least 32 bytes must be
  140.      *            available within this byte array.
  141.      * @return the converted object id.
  142.      */
  143.     public static final LongObjectId fromRaw(byte[] bs) {
  144.         return fromRaw(bs, 0);
  145.     }

  147.     /**
  148.      * Convert a LongObjectId from raw binary representation.
  149.      *
  150.      * @param bs
  151.      *            the raw byte buffer to read from. At least 32 bytes after p
  152.      *            must be available within this byte array.
  153.      * @param p
  154.      *            position to read the first byte of data from.
  155.      * @return the converted object id.
  156.      */
  157.     public static final LongObjectId fromRaw(byte[] bs, int p) {
  158.         final long a = NB.decodeInt64(bs, p);
  159.         final long b = NB.decodeInt64(bs, p + 8);
  160.         final long c = NB.decodeInt64(bs, p + 16);
  161.         final long d = NB.decodeInt64(bs, p + 24);
  162.         return new LongObjectId(a, b, c, d);
  163.     }

  165.     /**
  166.      * Convert a LongObjectId from raw binary representation.
  167.      *
  168.      * @param is
  169.      *            the raw long buffer to read from. At least 4 longs must be
  170.      *            available within this long array.
  171.      * @return the converted object id.
  172.      */
  173.     public static final LongObjectId fromRaw(long[] is) {
  174.         return fromRaw(is, 0);
  175.     }

  177.     /**
  178.      * Convert a LongObjectId from raw binary representation.
  179.      *
  180.      * @param is
  181.      *            the raw long buffer to read from. At least 4 longs after p
  182.      *            must be available within this long array.
  183.      * @param p
  184.      *            position to read the first long of data from.
  185.      * @return the converted object id.
  186.      */
  187.     public static final LongObjectId fromRaw(long[] is, int p) {
  188.         return new LongObjectId(is[p], is[p + 1], is[p + 2], is[p + 3]);
  189.     }

  191.     /**
  192.      * Convert a LongObjectId from hex characters (US-ASCII).
  193.      *
  194.      * @param buf
  195.      *            the US-ASCII buffer to read from. At least 64 bytes after
  196.      *            offset must be available within this byte array.
  197.      * @param offset
  198.      *            position to read the first character from.
  199.      * @return the converted object id.
  200.      */
  201.     public static final LongObjectId fromString(byte[] buf, int offset) {
  202.         return fromHexString(buf, offset);
  203.     }

  205.     /**
  206.      * Convert a LongObjectId from hex characters.
  207.      *
  208.      * @param str
  209.      *            the string to read from. Must be 64 characters long.
  210.      * @return the converted object id.
  211.      */
  212.     public static LongObjectId fromString(String str) {
  213.         if (str.length() != Constants.LONG_OBJECT_ID_STRING_LENGTH)
  214.             throw new InvalidLongObjectIdException(str);
  215.         return fromHexString(org.eclipse.jgit.lib.Constants.encodeASCII(str),
  216.                 0);
  217.     }

  219.     private static final LongObjectId fromHexString(byte[] bs, int p) {
  220.         try {
  221.             final long a = RawParseUtils.parseHexInt64(bs, p);
  222.             final long b = RawParseUtils.parseHexInt64(bs, p + 16);
  223.             final long c = RawParseUtils.parseHexInt64(bs, p + 32);
  224.             final long d = RawParseUtils.parseHexInt64(bs, p + 48);
  225.             return new LongObjectId(a, b, c, d);
  226.         } catch (ArrayIndexOutOfBoundsException e) {
  227.             InvalidLongObjectIdException e1 = new InvalidLongObjectIdException(
  228.                     bs, p, Constants.LONG_OBJECT_ID_STRING_LENGTH);
  229.             e1.initCause(e);
  230.             throw e1;
  231.         }
  232.     }

  234.     LongObjectId(final long new_1, final long new_2, final long new_3,
  235.             final long new_4) {
  236.         w1 = new_1;
  237.         w2 = new_2;
  238.         w3 = new_3;
  239.         w4 = new_4;
  240.     }

  242.     /**
  243.      * Initialize this instance by copying another existing LongObjectId.
  244.      * <p>
  245.      * This constructor is mostly useful for subclasses which want to extend a
  246.      * LongObjectId with more properties, but initialize from an existing
  247.      * LongObjectId instance acquired by other means.
  248.      *
  249.      * @param src
  250.      *            another already parsed LongObjectId to copy the value out of.
  251.      */
  252.     protected LongObjectId(AnyLongObjectId src) {
  253.         w1 = src.w1;
  254.         w2 = src.w2;
  255.         w3 = src.w3;
  256.         w4 = src.w4;
  257.     }

  259.     /** {@inheritDoc} */
  260.     @Override
  261.     public LongObjectId toObjectId() {
  262.         return this;
  263.     }

  265.     private void writeObject(ObjectOutputStream os) throws IOException {
  266.         os.writeLong(w1);
  267.         os.writeLong(w2);
  268.         os.writeLong(w3);
  269.         os.writeLong(w4);
  270.     }

  272.     private void readObject(ObjectInputStream ois) throws IOException {
  273.         w1 = ois.readLong();
  274.         w2 = ois.readLong();
  275.         w3 = ois.readLong();
  276.         w4 = ois.readLong();
  277.     }
  278. }
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