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Apache Commons Compress software defines an API for working with compression and archive formats. These include: bzip2, gzip, pack200, lzma, xz, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4, Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj.

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/*
 * CRC32Hash
 *
 * Authors: Lasse Collin 
 *          Igor Pavlov 
 *
 * This file has been put into the public domain.
 * You can do whatever you want with this file.
 */

package org.tukaani.xz.lz;

/**
 * Provides a CRC32 table using the polynomial from IEEE 802.3.
 */
class CRC32Hash {
    private static final int CRC32_POLY = 0xEDB88320;

    static final int[] crcTable = new int[256];

    static {
        for (int i = 0; i < 256; ++i) {
            int r = i;

            for (int j = 0; j < 8; ++j) {
                if ((r & 1) != 0)
                    r = (r >>> 1) ^ CRC32_POLY;
                else
                    r >>>= 1;
            }

            crcTable[i] = r;
        }
    }
}