Bzip2DivSufSort.java — netty Source File

Source Code

/*
 * Copyright 2014 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.handler.codec.compression;

/**
 * DivSufSort suffix array generator.<br>
 *
 * Based on <a href="https://code.google.com/p/libdivsufsort/">libdivsufsort</a> 1.2.3 patched to support Bzip2.<br>
 * This is a simple conversion of the original C with two minor bugfixes applied (see "BUGFIX"
 * comments within the class). Documentation within the class is largely absent.
 */
final class Bzip2DivSufSort {

    private static final int STACK_SIZE = 64;
    private static final int BUCKET_A_SIZE = 256;
    private static final int BUCKET_B_SIZE = 65536;
    private static final int SS_BLOCKSIZE = 1024;
    private static final int INSERTIONSORT_THRESHOLD = 8;

    private static final int[] LOG_2_TABLE = {
        -1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
         5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
         6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
         6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
         7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
         7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
         7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
         7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
    };

    private final int[] SA;
    private final byte[] T;
    private final int n;

    /**
     * @param block The input array
     * @param bwtBlock The output array
     * @param blockLength The length of the input data
     */
    Bzip2DivSufSort(final byte[] block, final int[] bwtBlock, final int blockLength) {
        T = block;
        SA = bwtBlock;
        n = blockLength;
    }

    private static void swapElements(final int[] array1, final int idx1, final int[] array2, final int idx2) {
        final int temp = array1[idx1];
// ... (2058 more lines)