    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 *   https://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.commons.compress.compressors.bzip2;
    020
    021import java.io.IOException;
    022import java.io.OutputStream;
    023import java.util.Arrays;
    024
    025import org.apache.commons.compress.compressors.CompressorOutputStream;
    026
    027/**
    028 * An output stream that compresses into the BZip2 format into another stream.
    029 *
    030 * <p>
    031 * The compression requires large amounts of memory. Thus you should call the {@link #close() close()} method as soon as possible, to force
    032 * {@code BZip2CompressorOutputStream} to release the allocated memory.
    033 * </p>
    034 *
    035 * <p>
    036 * You can shrink the amount of allocated memory and maybe raise the compression speed by choosing a lower blocksize, which in turn may cause a lower
    037 * compression ratio. You can avoid unnecessary memory allocation by avoiding using a blocksize which is bigger than the size of the input.
    038 * </p>
    039 *
    040 * <p>
    041 * You can compute the memory usage for compressing by the following formula:
    042 * </p>
    043 *
    044 * <pre>
    045 * &lt;code&gt;400k + (9 * blocksize)&lt;/code&gt;.
    046 * </pre>
    047 *
    048 * <p>
    049 * To get the memory required for decompression by {@link BZip2CompressorInputStream} use
    050 * </p>
    051 *
    052 * <pre>
    053 * &lt;code&gt;65k + (5 * blocksize)&lt;/code&gt;.
    054 * </pre>
    055 *
    056 * <table style="width:100%" border="1">
    057 * <caption>Memory usage by blocksize</caption>
    058 * <tr>
    059 * <th colspan="3">Memory usage by blocksize</th>
    060 * </tr>
    061 * <tr>
    062 * <th style="text-align: right">Blocksize</th>
    063 * <th style="text-align: right">Compression<br>
    064 * memory usage</th>
    065 * <th style="text-align: right">Decompression<br>
    066 * memory usage</th>
    067 * </tr>
    068 * <tr>
    069 * <td style="text-align: right">100k</td>
    070 * <td style="text-align: right">1300k</td>
    071 * <td style="text-align: right">565k</td>
    072 * </tr>
    073 * <tr>
    074 * <td style="text-align: right">200k</td>
    075 * <td style="text-align: right">2200k</td>
    076 * <td style="text-align: right">1065k</td>
    077 * </tr>
    078 * <tr>
    079 * <td style="text-align: right">300k</td>
    080 * <td style="text-align: right">3100k</td>
    081 * <td style="text-align: right">1565k</td>
    082 * </tr>
    083 * <tr>
    084 * <td style="text-align: right">400k</td>
    085 * <td style="text-align: right">4000k</td>
    086 * <td style="text-align: right">2065k</td>
    087 * </tr>
    088 * <tr>
    089 * <td style="text-align: right">500k</td>
    090 * <td style="text-align: right">4900k</td>
    091 * <td style="text-align: right">2565k</td>
    092 * </tr>
    093 * <tr>
    094 * <td style="text-align: right">600k</td>
    095 * <td style="text-align: right">5800k</td>
    096 * <td style="text-align: right">3065k</td>
    097 * </tr>
    098 * <tr>
    099 * <td style="text-align: right">700k</td>
    100 * <td style="text-align: right">6700k</td>
    101 * <td style="text-align: right">3565k</td>
    102 * </tr>
    103 * <tr>
    104 * <td style="text-align: right">800k</td>
    105 * <td style="text-align: right">7600k</td>
    106 * <td style="text-align: right">4065k</td>
    107 * </tr>
    108 * <tr>
    109 * <td style="text-align: right">900k</td>
    110 * <td style="text-align: right">8500k</td>
    111 * <td style="text-align: right">4565k</td>
    112 * </tr>
    113 * </table>
    114 *
    115 * <p>
    116 * For decompression {@code BZip2CompressorInputStream} allocates less memory if the bzipped input is smaller than one block.
    117 * </p>
    118 *
    119 * <p>
    120 * Instances of this class are not threadsafe.
    121 * </p>
    122 *
    123 * <p>
    124 * TODO: Update to BZip2 1.0.1
    125 * </p>
    126 *
    127 * @NotThreadSafe
    128 */
    129public class BZip2CompressorOutputStream extends CompressorOutputStream<OutputStream> implements BZip2Constants {
    130
    131    static final class Data {
    132
    133        // with blockSize 900k
    134        /* maps unsigned byte => "does it occur in block" */
    135        final boolean[] inUse = new boolean[256]; // 256 byte
    136        final byte[] unseqToSeq = new byte[256]; // 256 byte
    137        final int[] mtfFreq = new int[MAX_ALPHA_SIZE]; // 1032 byte
    138        final byte[] selector = new byte[MAX_SELECTORS]; // 18002 byte
    139        final byte[] selectorMtf = new byte[MAX_SELECTORS]; // 18002 byte
    140
    141        final byte[] generateMTFValues_yy = new byte[256]; // 256 byte
    142        final byte[][] sendMTFValues_len = new byte[N_GROUPS][MAX_ALPHA_SIZE]; // 1548
    143        // byte
    144        final int[][] sendMTFValues_rfreq = new int[N_GROUPS][MAX_ALPHA_SIZE]; // 6192
    145        // byte
    146        final int[] sendMTFValues_fave = new int[N_GROUPS]; // 24 byte
    147        final short[] sendMTFValues_cost = new short[N_GROUPS]; // 12 byte
    148        final int[][] sendMTFValues_code = new int[N_GROUPS][MAX_ALPHA_SIZE]; // 6192
    149        // byte
    150        final byte[] sendMTFValues2_pos = new byte[N_GROUPS]; // 6 byte
    151        final boolean[] sentMTFValues4_inUse16 = new boolean[16]; // 16 byte
    152
    153        final int[] heap = new int[MAX_ALPHA_SIZE + 2]; // 1040 byte
    154        final int[] weight = new int[MAX_ALPHA_SIZE * 2]; // 2064 byte
    155        final int[] parent = new int[MAX_ALPHA_SIZE * 2]; // 2064 byte
    156
    157        // ------------
    158        // 333408 byte
    159
    160        /*
    161         * holds the RLEd block of original data starting at index 1. After sorting the last byte added to the buffer is at index 0.
    162         */
    163        final byte[] block; // 900021 byte
    164        /*
    165         * maps index in Burrows-Wheeler transformed block => index of byte in original block
    166         */
    167        final int[] fmap; // 3600000 byte
    168        final char[] sfmap; // 3600000 byte
    169        // ------------
    170        // 8433529 byte
    171        // ============
    172
    173        /**
    174         * Index of original line in Burrows-Wheeler table.
    175         *
    176         * <p>
    177         * This is the index in fmap that points to the last byte of the original data.
    178         * </p>
    179         */
    180        int origPtr;
    181
    182        Data(final int blockSize100k) {
    183            final int n = blockSize100k * BASEBLOCKSIZE;
    184            this.block = new byte[n + 1 + NUM_OVERSHOOT_BYTES];
    185            this.fmap = new int[n];
    186            this.sfmap = new char[2 * n];
    187        }
    188
    189    }
    190
    191    /**
    192     * The minimum supported blocksize {@code  == 1}.
    193     */
    194    public static final int MIN_BLOCKSIZE = 1;
    195
    196    /**
    197     * The maximum supported blocksize {@code  == 9}.
    198     */
    199    public static final int MAX_BLOCKSIZE = 9;
    200    private static final int GREATER_ICOST = 15;
    201
    202    private static final int LESSER_ICOST = 0;
    203
    204    /**
    205     * Chooses a blocksize based on the given length of the data to compress.
    206     *
    207     * @return The blocksize, between {@link #MIN_BLOCKSIZE} and {@link #MAX_BLOCKSIZE} both inclusive. For a negative {@code inputLength} this method returns
    208     *         {@code MAX_BLOCKSIZE} always.
    209     *
    210     * @param inputLength The length of the data which will be compressed by {@code BZip2CompressorOutputStream}.
    211     */
    212    public static int chooseBlockSize(final long inputLength) {
    213        return inputLength > 0 ? (int) Math.min(inputLength / 132000 + 1, 9) : MAX_BLOCKSIZE;
    214    }
    215
    216    private static void hbAssignCodes(final int[] code, final byte[] length, final int minLen, final int maxLen, final int alphaSize) {
    217        int vec = 0;
    218        for (int n = minLen; n <= maxLen; n++) {
    219            for (int i = 0; i < alphaSize; i++) {
    220                if ((length[i] & 0xff) == n) {
    221                    code[i] = vec;
    222                    vec++;
    223                }
    224            }
    225            vec <<= 1;
    226        }
    227    }
    228
    229    private static void hbMakeCodeLengths(final byte[] len, final int[] freq, final Data dat, final int alphaSize, final int maxLen) {
    230        /*
    231         * Nodes and heap entries run from 1. Entry 0 for both the heap and nodes is a sentinel.
    232         */
    233        final int[] heap = dat.heap;
    234        final int[] weight = dat.weight;
    235        final int[] parent = dat.parent;
    236
    237        for (int i = alphaSize; --i >= 0;) {
    238            weight[i + 1] = (freq[i] == 0 ? 1 : freq[i]) << 8;
    239        }
    240
    241        for (boolean tooLong = true; tooLong;) {
    242            tooLong = false;
    243
    244            int nNodes = alphaSize;
    245            int nHeap = 0;
    246            heap[0] = 0;
    247            weight[0] = 0;
    248            parent[0] = -2;
    249
    250            for (int i = 1; i <= alphaSize; i++) {
    251                parent[i] = -1;
    252                nHeap++;
    253                heap[nHeap] = i;
    254
    255                int zz = nHeap;
    256                final int tmp = heap[zz];
    257                while (weight[tmp] < weight[heap[zz >> 1]]) {
    258                    heap[zz] = heap[zz >> 1];
    259                    zz >>= 1;
    260                }
    261                heap[zz] = tmp;
    262            }
    263
    264            while (nHeap > 1) {
    265                final int n1 = heap[1];
    266                heap[1] = heap[nHeap];
    267                nHeap--;
    268
    269                int yy = 0;
    270                int zz = 1;
    271                int tmp = heap[1];
    272
    273                while (true) {
    274                    yy = zz << 1;
    275
    276                    if (yy > nHeap) {
    277                        break;
    278                    }
    279
    280                    if (yy < nHeap && weight[heap[yy + 1]] < weight[heap[yy]]) {
    281                        yy++;
    282                    }
    283
    284                    if (weight[tmp] < weight[heap[yy]]) {
    285                        break;
    286                    }
    287
    288                    heap[zz] = heap[yy];
    289                    zz = yy;
    290                }
    291
    292                heap[zz] = tmp;
    293
    294                final int n2 = heap[1];
    295                heap[1] = heap[nHeap];
    296                nHeap--;
    297
    298                yy = 0;
    299                zz = 1;
    300                tmp = heap[1];
    301
    302                while (true) {
    303                    yy = zz << 1;
    304
    305                    if (yy > nHeap) {
    306                        break;
    307                    }
    308
    309                    if (yy < nHeap && weight[heap[yy + 1]] < weight[heap[yy]]) {
    310                        yy++;
    311                    }
    312
    313                    if (weight[tmp] < weight[heap[yy]]) {
    314                        break;
    315                    }
    316
    317                    heap[zz] = heap[yy];
    318                    zz = yy;
    319                }
    320
    321                heap[zz] = tmp;
    322                nNodes++;
    323                parent[n1] = parent[n2] = nNodes;
    324
    325                final int weight_n1 = weight[n1];
    326                final int weight_n2 = weight[n2];
    327                weight[nNodes] = (weight_n1 & 0xffffff00) + (weight_n2 & 0xffffff00) | 1 + Math.max(weight_n1 & 0x000000ff, weight_n2 & 0x000000ff);
    328
    329                parent[nNodes] = -1;
    330                nHeap++;
    331                heap[nHeap] = nNodes;
    332
    333                tmp = 0;
    334                zz = nHeap;
    335                tmp = heap[zz];
    336                final int weight_tmp = weight[tmp];
    337                while (weight_tmp < weight[heap[zz >> 1]]) {
    338                    heap[zz] = heap[zz >> 1];
    339                    zz >>= 1;
    340                }
    341                heap[zz] = tmp;
    342
    343            }
    344
    345            for (int i = 1; i <= alphaSize; i++) {
    346                int j = 0;
    347                int k = i;
    348
    349                for (int parent_k; (parent_k = parent[k]) >= 0;) {
    350                    k = parent_k;
    351                    j++;
    352                }
    353
    354                len[i - 1] = (byte) j;
    355                if (j > maxLen) {
    356                    tooLong = true;
    357                }
    358            }
    359
    360            if (tooLong) {
    361                for (int i = 1; i < alphaSize; i++) {
    362                    int j = weight[i] >> 8;
    363                    j = 1 + (j >> 1);
    364                    weight[i] = j << 8;
    365                }
    366            }
    367        }
    368    }
    369
    370    /**
    371     * Index of the last char in the block, so the block size == last + 1.
    372     */
    373    private int last;
    374    /**
    375     * Always: in the range 0 .. 9. The current block size is 100000 * this number.
    376     */
    377    private final int blockSize100k;
    378
    379    private int bsBuff;
    380
    381    private int bsLive;
    382
    383    private final CRC crc = new CRC();
    384    private int nInUse;
    385
    386    private int nMTF;
    387    private int currentChar = -1;
    388    private int runLength;
    389
    390    private int combinedCRC;
    391
    392    private final int allowableBlockSize;
    393    /**
    394     * All memory intensive stuff.
    395     */
    396    private Data data;
    397
    398    private BlockSort blockSorter;
    399
    400    /**
    401     * Constructs a new {@code BZip2CompressorOutputStream} with a blocksize of 900k.
    402     *
    403     * @param out the destination stream.
    404     * @throws IOException          if an I/O error occurs in the specified stream.
    405     * @throws NullPointerException if {@code out == null}.
    406     */
    407    public BZip2CompressorOutputStream(final OutputStream out) throws IOException {
    408        this(out, MAX_BLOCKSIZE);
    409    }
    410
    411    /**
    412     * Constructs a new {@code BZip2CompressorOutputStream} with specified blocksize.
    413     *
    414     * @param out       the destination stream.
    415     * @param blockSize the blockSize as 100k units.
    416     * @throws IOException              if an I/O error occurs in the specified stream.
    417     * @throws IllegalArgumentException if {@code (blockSize &lt; 1) || (blockSize &gt; 9)}.
    418     * @throws NullPointerException     if {@code out == null}.
    419     * @see #MIN_BLOCKSIZE
    420     * @see #MAX_BLOCKSIZE
    421     */
    422    public BZip2CompressorOutputStream(final OutputStream out, final int blockSize) throws IOException {
    423        super(out);
    424        if (blockSize < 1) {
    425            throw new IllegalArgumentException("blockSize(" + blockSize + ") < 1");
    426        }
    427        if (blockSize > 9) {
    428            throw new IllegalArgumentException("blockSize(" + blockSize + ") > 9");
    429        }
    430        this.blockSize100k = blockSize;
    431        /* 20 is just a paranoia constant */
    432        this.allowableBlockSize = this.blockSize100k * BASEBLOCKSIZE - 20;
    433        init();
    434    }
    435
    436    private void blockSort() {
    437        blockSorter.blockSort(data, last);
    438    }
    439
    440    private void bsFinishedWithStream() throws IOException {
    441        while (this.bsLive > 0) {
    442            final int ch = this.bsBuff >> 24;
    443            this.out.write(ch); // write 8-bit
    444            this.bsBuff <<= 8;
    445            this.bsLive -= 8;
    446        }
    447    }
    448
    449    private void bsPutInt(final int u) throws IOException {
    450        bsW(8, u >> 24 & 0xff);
    451        bsW(8, u >> 16 & 0xff);
    452        bsW(8, u >> 8 & 0xff);
    453        bsW(8, u & 0xff);
    454    }
    455
    456    private void bsPutUByte(final int c) throws IOException {
    457        bsW(8, c);
    458    }
    459
    460    private void bsW(final int n, final int v) throws IOException {
    461        final OutputStream outShadow = this.out;
    462        int bsLiveShadow = this.bsLive;
    463        int bsBuffShadow = this.bsBuff;
    464
    465        while (bsLiveShadow >= 8) {
    466            outShadow.write(bsBuffShadow >> 24); // write 8-bit
    467            bsBuffShadow <<= 8;
    468            bsLiveShadow -= 8;
    469        }
    470
    471        this.bsBuff = bsBuffShadow | v << 32 - bsLiveShadow - n;
    472        this.bsLive = bsLiveShadow + n;
    473    }
    474
    475    @Override
    476    public void close() throws IOException {
    477        if (!isClosed()) {
    478            try {
    479                finish();
    480            } finally {
    481                super.close();
    482            }
    483        }
    484    }
    485
    486    private void endBlock() throws IOException {
    487        final int blockCRC = this.crc.getValue();
    488        this.combinedCRC = this.combinedCRC << 1 | this.combinedCRC >>> 31;
    489        this.combinedCRC ^= blockCRC;
    490
    491        // empty block at end of file
    492        if (this.last == -1) {
    493            return;
    494        }
    495
    496        /* sort the block and establish posn of original string */
    497        blockSort();
    498
    499        /*
    500         * A 6-byte block header, the value chosen arbitrarily as 0x314159265359 :-). A 32 bit value does not really give a strong enough guarantee that the
    501         * value will not appear by chance in the compressed data stream. Worst-case probability of this event, for a 900k block, is about 2.0e-3 for 32 bits,
    502         * 1.0e-5 for 40 bits and 4.0e-8 for 48 bits. For a compressed file of size 100Gb -- about 100000 blocks -- only a 48-bit marker will do. NB: normal
    503         * compression/ decompression doesn't rely on these statistical properties. They are only important when trying to recover blocks from damaged files.
    504         */
    505        bsPutUByte(0x31);
    506        bsPutUByte(0x41);
    507        bsPutUByte(0x59);
    508        bsPutUByte(0x26);
    509        bsPutUByte(0x53);
    510        bsPutUByte(0x59);
    511
    512        /* Now the block's CRC, so it is in a known place. */
    513        bsPutInt(blockCRC);
    514
    515        /* Now a single bit indicating no randomization. */
    516        bsW(1, 0);
    517
    518        /* Finally, block's contents proper. */
    519        moveToFrontCodeAndSend();
    520    }
    521
    522    private void endCompression() throws IOException {
    523        /*
    524         * Now another magic 48-bit number, 0x177245385090, to indicate the end of the last block. (sqrt(pi), if you want to know. I did want to use e, but it
    525         * contains too much repetition -- 27 18 28 18 28 46 -- for me to feel statistically comfortable. Call me paranoid.)
    526         */
    527        bsPutUByte(0x17);
    528        bsPutUByte(0x72);
    529        bsPutUByte(0x45);
    530        bsPutUByte(0x38);
    531        bsPutUByte(0x50);
    532        bsPutUByte(0x90);
    533
    534        bsPutInt(this.combinedCRC);
    535        bsFinishedWithStream();
    536    }
    537
    538    @Override
    539    public void finish() throws IOException {
    540        if (!isClosed()) {
    541            try {
    542                if (this.runLength > 0) {
    543                    writeRun();
    544                }
    545                this.currentChar = -1;
    546                endBlock();
    547                endCompression();
    548            } finally {
    549                this.blockSorter = null;
    550                this.data = null;
    551            }
    552        }
    553    }
    554
    555    @Override
    556    public void flush() throws IOException {
    557        if (out != null) {
    558            super.flush();
    559        }
    560    }
    561
    562    /*
    563     * Performs Move-To-Front on the Burrows-Wheeler transformed buffer, storing the MTFed data in data.sfmap in RUNA/RUNB run-length-encoded form.
    564     *
    565     * <p>Keeps track of byte frequencies in data.mtfFreq at the same time.</p>
    566     */
    567    private void generateMTFValues() {
    568        final int lastShadow = this.last;
    569        final Data dataShadow = this.data;
    570        final boolean[] inUse = dataShadow.inUse;
    571        final byte[] block = dataShadow.block;
    572        final int[] fmap = dataShadow.fmap;
    573        final char[] sfmap = dataShadow.sfmap;
    574        final int[] mtfFreq = dataShadow.mtfFreq;
    575        final byte[] unseqToSeq = dataShadow.unseqToSeq;
    576        final byte[] yy = dataShadow.generateMTFValues_yy;
    577
    578        // make maps
    579        int nInUseShadow = 0;
    580        for (int i = 0; i < 256; i++) {
    581            if (inUse[i]) {
    582                unseqToSeq[i] = (byte) nInUseShadow;
    583                nInUseShadow++;
    584            }
    585        }
    586        this.nInUse = nInUseShadow;
    587
    588        final int eob = nInUseShadow + 1;
    589
    590        Arrays.fill(mtfFreq, 0, eob + 1, 0);
    591
    592        for (int i = nInUseShadow; --i >= 0;) {
    593            yy[i] = (byte) i;
    594        }
    595
    596        int wr = 0;
    597        int zPend = 0;
    598
    599        for (int i = 0; i <= lastShadow; i++) {
    600            final byte ll_i = unseqToSeq[block[fmap[i]] & 0xff];
    601            byte tmp = yy[0];
    602            int j = 0;
    603
    604            while (ll_i != tmp) {
    605                j++;
    606                final byte tmp2 = tmp;
    607                tmp = yy[j];
    608                yy[j] = tmp2;
    609            }
    610            yy[0] = tmp;
    611
    612            if (j == 0) {
    613                zPend++;
    614            } else {
    615                if (zPend > 0) {
    616                    zPend--;
    617                    while (true) {
    618                        if ((zPend & 1) == 0) {
    619                            sfmap[wr] = RUNA;
    620                            wr++;
    621                            mtfFreq[RUNA]++;
    622                        } else {
    623                            sfmap[wr] = RUNB;
    624                            wr++;
    625                            mtfFreq[RUNB]++;
    626                        }
    627
    628                        if (zPend < 2) {
    629                            break;
    630                        }
    631                        zPend = zPend - 2 >> 1;
    632                    }
    633                    zPend = 0;
    634                }
    635                sfmap[wr] = (char) (j + 1);
    636                wr++;
    637                mtfFreq[j + 1]++;
    638            }
    639        }
    640
    641        if (zPend > 0) {
    642            zPend--;
    643            while (true) {
    644                if ((zPend & 1) == 0) {
    645                    sfmap[wr] = RUNA;
    646                    wr++;
    647                    mtfFreq[RUNA]++;
    648                } else {
    649                    sfmap[wr] = RUNB;
    650                    wr++;
    651                    mtfFreq[RUNB]++;
    652                }
    653
    654                if (zPend < 2) {
    655                    break;
    656                }
    657                zPend = zPend - 2 >> 1;
    658            }
    659        }
    660
    661        sfmap[wr] = (char) eob;
    662        mtfFreq[eob]++;
    663        this.nMTF = wr + 1;
    664    }
    665
    666    /**
    667     * Returns the blocksize parameter specified at construction time.
    668     *
    669     * @return the blocksize parameter specified at construction time
    670     */
    671    public final int getBlockSize() {
    672        return this.blockSize100k;
    673    }
    674
    675    /**
    676     * Writes magic bytes like BZ on the first position of the stream and bytes indicating the file-format, which is huffmanized, followed by a digit indicating
    677     * blockSize100k.
    678     *
    679     * @throws IOException if the magic bytes could not been written
    680     */
    681    private void init() throws IOException {
    682        bsPutUByte('B');
    683        bsPutUByte('Z');
    684
    685        this.data = new Data(this.blockSize100k);
    686        this.blockSorter = new BlockSort(this.data);
    687
    688        // huffmanized magic bytes
    689        bsPutUByte('h');
    690        bsPutUByte('0' + this.blockSize100k);
    691
    692        this.combinedCRC = 0;
    693        initBlock();
    694    }
    695
    696    private void initBlock() {
    697        // blockNo++;
    698        this.crc.reset();
    699        this.last = -1;
    700        // ch = 0;
    701
    702        final boolean[] inUse = this.data.inUse;
    703        for (int i = 256; --i >= 0;) {
    704            inUse[i] = false;
    705        }
    706
    707    }
    708
    709    private void moveToFrontCodeAndSend() throws IOException {
    710        bsW(24, this.data.origPtr);
    711        generateMTFValues();
    712        sendMTFValues();
    713    }
    714
    715    private void sendMTFValues() throws IOException {
    716        final byte[][] len = this.data.sendMTFValues_len;
    717        final int alphaSize = this.nInUse + 2;
    718
    719        for (int t = N_GROUPS; --t >= 0;) {
    720            final byte[] len_t = len[t];
    721            for (int v = alphaSize; --v >= 0;) {
    722                len_t[v] = GREATER_ICOST;
    723            }
    724        }
    725
    726        /* Decide how many coding tables to use */
    727        // assert (this.nMTF > 0) : this.nMTF;
    728        final int nGroups = this.nMTF < 200 ? 2 : this.nMTF < 600 ? 3 : this.nMTF < 1200 ? 4 : this.nMTF < 2400 ? 5 : 6;
    729
    730        /* Generate an initial set of coding tables */
    731        sendMTFValues0(nGroups, alphaSize);
    732
    733        /*
    734         * Iterate up to N_ITERS times to improve the tables.
    735         */
    736        final int nSelectors = sendMTFValues1(nGroups, alphaSize);
    737
    738        /* Compute MTF values for the selectors. */
    739        sendMTFValues2(nGroups, nSelectors);
    740
    741        /* Assign actual codes for the tables. */
    742        sendMTFValues3(nGroups, alphaSize);
    743
    744        /* Transmit the mapping table. */
    745        sendMTFValues4();
    746
    747        /* Now the selectors. */
    748        sendMTFValues5(nGroups, nSelectors);
    749
    750        /* Now the coding tables. */
    751        sendMTFValues6(nGroups, alphaSize);
    752
    753        /* And finally, the block data proper */
    754        sendMTFValues7();
    755    }
    756
    757    private void sendMTFValues0(final int nGroups, final int alphaSize) {
    758        final byte[][] len = this.data.sendMTFValues_len;
    759        final int[] mtfFreq = this.data.mtfFreq;
    760
    761        int remF = this.nMTF;
    762        int gs = 0;
    763
    764        for (int nPart = nGroups; nPart > 0; nPart--) {
    765            final int tFreq = remF / nPart;
    766            int ge = gs - 1;
    767            int aFreq = 0;
    768
    769            for (final int a = alphaSize - 1; aFreq < tFreq && ge < a;) {
    770                aFreq += mtfFreq[++ge];
    771            }
    772
    773            if (ge > gs && nPart != nGroups && nPart != 1 && (nGroups - nPart & 1) != 0) {
    774                aFreq -= mtfFreq[ge--];
    775            }
    776
    777            final byte[] len_np = len[nPart - 1];
    778            for (int v = alphaSize; --v >= 0;) {
    779                if (v >= gs && v <= ge) {
    780                    len_np[v] = LESSER_ICOST;
    781                } else {
    782                    len_np[v] = GREATER_ICOST;
    783                }
    784            }
    785
    786            gs = ge + 1;
    787            remF -= aFreq;
    788        }
    789    }
    790
    791    private int sendMTFValues1(final int nGroups, final int alphaSize) {
    792        final Data dataShadow = this.data;
    793        final int[][] rfreq = dataShadow.sendMTFValues_rfreq;
    794        final int[] fave = dataShadow.sendMTFValues_fave;
    795        final short[] cost = dataShadow.sendMTFValues_cost;
    796        final char[] sfmap = dataShadow.sfmap;
    797        final byte[] selector = dataShadow.selector;
    798        final byte[][] len = dataShadow.sendMTFValues_len;
    799        final byte[] len_0 = len[0];
    800        final byte[] len_1 = len[1];
    801        final byte[] len_2 = len[2];
    802        final byte[] len_3 = len[3];
    803        final byte[] len_4 = len[4];
    804        final byte[] len_5 = len[5];
    805        final int nMTFShadow = this.nMTF;
    806
    807        int nSelectors = 0;
    808
    809        for (int iter = 0; iter < N_ITERS; iter++) {
    810            for (int t = nGroups; --t >= 0;) {
    811                fave[t] = 0;
    812                final int[] rfreqt = rfreq[t];
    813                for (int i = alphaSize; --i >= 0;) {
    814                    rfreqt[i] = 0;
    815                }
    816            }
    817
    818            nSelectors = 0;
    819
    820            for (int gs = 0; gs < this.nMTF;) {
    821                // Set group start & end marks.
    822
    823                // Calculate the cost of this group as coded by each of the
    824                // coding tables.
    825
    826                final int ge = Math.min(gs + G_SIZE - 1, nMTFShadow - 1);
    827
    828                final byte mask = (byte) 0xff;
    829                if (nGroups == N_GROUPS) {
    830                    // unrolled version of the else-block
    831
    832                    short cost0 = 0;
    833                    short cost1 = 0;
    834                    short cost2 = 0;
    835                    short cost3 = 0;
    836                    short cost4 = 0;
    837                    short cost5 = 0;
    838
    839                    for (int i = gs; i <= ge; i++) {
    840                        final int icv = sfmap[i];
    841                        cost0 += (short) (len_0[icv] & mask);
    842                        cost1 += (short) (len_1[icv] & mask);
    843                        cost2 += (short) (len_2[icv] & mask);
    844                        cost3 += (short) (len_3[icv] & mask);
    845                        cost4 += (short) (len_4[icv] & mask);
    846                        cost5 += (short) (len_5[icv] & mask);
    847                    }
    848
    849                    cost[0] = cost0;
    850                    cost[1] = cost1;
    851                    cost[2] = cost2;
    852                    cost[3] = cost3;
    853                    cost[4] = cost4;
    854                    cost[5] = cost5;
    855
    856                } else {
    857                    for (int t = nGroups; --t >= 0;) {
    858                        cost[t] = 0;
    859                    }
    860
    861                    for (int i = gs; i <= ge; i++) {
    862                        final int icv = sfmap[i];
    863                        for (int t = nGroups; --t >= 0;) {
    864                            cost[t] += (short) (len[t][icv] & mask);
    865                        }
    866                    }
    867                }
    868
    869                /*
    870                 * Find the coding table which is best for this group, and record its identity in the selector table.
    871                 */
    872                int bt = -1;
    873                for (int t = nGroups, bc = 999999999; --t >= 0;) {
    874                    final int cost_t = cost[t];
    875                    if (cost_t < bc) {
    876                        bc = cost_t;
    877                        bt = t;
    878                    }
    879                }
    880
    881                fave[bt]++;
    882                selector[nSelectors] = (byte) bt;
    883                nSelectors++;
    884
    885                /*
    886                 * Increment the symbol frequencies for the selected table.
    887                 */
    888                final int[] rfreq_bt = rfreq[bt];
    889                for (int i = gs; i <= ge; i++) {
    890                    rfreq_bt[sfmap[i]]++;
    891                }
    892
    893                gs = ge + 1;
    894            }
    895
    896            /*
    897             * Recompute the tables based on the accumulated frequencies.
    898             */
    899            for (int t = 0; t < nGroups; t++) {
    900                hbMakeCodeLengths(len[t], rfreq[t], this.data, alphaSize, 20);
    901            }
    902        }
    903
    904        return nSelectors;
    905    }
    906
    907    private void sendMTFValues2(final int nGroups, final int nSelectors) {
    908        // assert (nGroups < 8) : nGroups;
    909
    910        final Data dataShadow = this.data;
    911        final byte[] pos = dataShadow.sendMTFValues2_pos;
    912
    913        for (int i = nGroups; --i >= 0;) {
    914            pos[i] = (byte) i;
    915        }
    916
    917        for (int i = 0; i < nSelectors; i++) {
    918            final byte ll_i = dataShadow.selector[i];
    919            byte tmp = pos[0];
    920            int j = 0;
    921
    922            while (ll_i != tmp) {
    923                j++;
    924                final byte tmp2 = tmp;
    925                tmp = pos[j];
    926                pos[j] = tmp2;
    927            }
    928
    929            pos[0] = tmp;
    930            dataShadow.selectorMtf[i] = (byte) j;
    931        }
    932    }
    933
    934    private void sendMTFValues3(final int nGroups, final int alphaSize) {
    935        final int[][] code = this.data.sendMTFValues_code;
    936        final byte[][] len = this.data.sendMTFValues_len;
    937
    938        for (int t = 0; t < nGroups; t++) {
    939            int minLen = 32;
    940            int maxLen = 0;
    941            final byte[] len_t = len[t];
    942            for (int i = alphaSize; --i >= 0;) {
    943                final int l = len_t[i] & 0xff;
    944                if (l > maxLen) {
    945                    maxLen = l;
    946                }
    947                if (l < minLen) {
    948                    minLen = l;
    949                }
    950            }
    951
    952            // assert (maxLen <= 20) : maxLen;
    953            // assert (minLen >= 1) : minLen;
    954
    955            hbAssignCodes(code[t], len[t], minLen, maxLen, alphaSize);
    956        }
    957    }
    958
    959    private void sendMTFValues4() throws IOException {
    960        final boolean[] inUse = this.data.inUse;
    961        final boolean[] inUse16 = this.data.sentMTFValues4_inUse16;
    962
    963        for (int i = 16; --i >= 0;) {
    964            inUse16[i] = false;
    965            final int i16 = i * 16;
    966            for (int j = 16; --j >= 0;) {
    967                if (inUse[i16 + j]) {
    968                    inUse16[i] = true;
    969                    break;
    970                }
    971            }
    972        }
    973
    974        for (int i = 0; i < 16; i++) {
    975            bsW(1, inUse16[i] ? 1 : 0);
    976        }
    977
    978        final OutputStream outShadow = this.out;
    979        int bsLiveShadow = this.bsLive;
    980        int bsBuffShadow = this.bsBuff;
    981
    982        for (int i = 0; i < 16; i++) {
    983            if (inUse16[i]) {
    984                final int i16 = i * 16;
    985                for (int j = 0; j < 16; j++) {
    986                    // inlined: bsW(1, inUse[i16 + j] ? 1 : 0);
    987                    while (bsLiveShadow >= 8) {
    988                        outShadow.write(bsBuffShadow >> 24); // write 8-bit
    989                        bsBuffShadow <<= 8;
    990                        bsLiveShadow -= 8;
    991                    }
    992                    if (inUse[i16 + j]) {
    993                        bsBuffShadow |= 1 << 32 - bsLiveShadow - 1;
    994                    }
    995                    bsLiveShadow++;
    996                }
    997            }
    998        }
    999
    1000        this.bsBuff = bsBuffShadow;
    1001        this.bsLive = bsLiveShadow;
    1002    }
    1003
    1004    private void sendMTFValues5(final int nGroups, final int nSelectors) throws IOException {
    1005        bsW(3, nGroups);
    1006        bsW(15, nSelectors);
    1007
    1008        final OutputStream outShadow = this.out;
    1009        final byte[] selectorMtf = this.data.selectorMtf;
    1010
    1011        int bsLiveShadow = this.bsLive;
    1012        int bsBuffShadow = this.bsBuff;
    1013
    1014        for (int i = 0; i < nSelectors; i++) {
    1015            for (int j = 0, hj = selectorMtf[i] & 0xff; j < hj; j++) {
    1016                // inlined: bsW(1, 1);
    1017                while (bsLiveShadow >= 8) {
    1018                    outShadow.write(bsBuffShadow >> 24);
    1019                    bsBuffShadow <<= 8;
    1020                    bsLiveShadow -= 8;
    1021                }
    1022                bsBuffShadow |= 1 << 32 - bsLiveShadow - 1;
    1023                bsLiveShadow++;
    1024            }
    1025
    1026            // inlined: bsW(1, 0);
    1027            while (bsLiveShadow >= 8) {
    1028                outShadow.write(bsBuffShadow >> 24);
    1029                bsBuffShadow <<= 8;
    1030                bsLiveShadow -= 8;
    1031            }
    1032            // bsBuffShadow |= 0 << (32 - bsLiveShadow - 1);
    1033            bsLiveShadow++;
    1034        }
    1035
    1036        this.bsBuff = bsBuffShadow;
    1037        this.bsLive = bsLiveShadow;
    1038    }
    1039
    1040    private void sendMTFValues6(final int nGroups, final int alphaSize) throws IOException {
    1041        final byte[][] len = this.data.sendMTFValues_len;
    1042        final OutputStream outShadow = this.out;
    1043
    1044        int bsLiveShadow = this.bsLive;
    1045        int bsBuffShadow = this.bsBuff;
    1046
    1047        for (int t = 0; t < nGroups; t++) {
    1048            final byte[] len_t = len[t];
    1049            int curr = len_t[0] & 0xff;
    1050
    1051            // inlined: bsW(5, curr);
    1052            while (bsLiveShadow >= 8) {
    1053                outShadow.write(bsBuffShadow >> 24); // write 8-bit
    1054                bsBuffShadow <<= 8;
    1055                bsLiveShadow -= 8;
    1056            }
    1057            bsBuffShadow |= curr << 32 - bsLiveShadow - 5;
    1058            bsLiveShadow += 5;
    1059
    1060            for (int i = 0; i < alphaSize; i++) {
    1061                final int lti = len_t[i] & 0xff;
    1062                while (curr < lti) {
    1063                    // inlined: bsW(2, 2);
    1064                    while (bsLiveShadow >= 8) {
    1065                        outShadow.write(bsBuffShadow >> 24); // write 8-bit
    1066                        bsBuffShadow <<= 8;
    1067                        bsLiveShadow -= 8;
    1068                    }
    1069                    bsBuffShadow |= 2 << 32 - bsLiveShadow - 2;
    1070                    bsLiveShadow += 2;
    1071
    1072                    curr++; /* 10 */
    1073                }
    1074
    1075                while (curr > lti) {
    1076                    // inlined: bsW(2, 3);
    1077                    while (bsLiveShadow >= 8) {
    1078                        outShadow.write(bsBuffShadow >> 24); // write 8-bit
    1079                        bsBuffShadow <<= 8;
    1080                        bsLiveShadow -= 8;
    1081                    }
    1082                    bsBuffShadow |= 3 << 32 - bsLiveShadow - 2;
    1083                    bsLiveShadow += 2;
    1084
    1085                    curr--; /* 11 */
    1086                }
    1087
    1088                // inlined: bsW(1, 0);
    1089                while (bsLiveShadow >= 8) {
    1090                    outShadow.write(bsBuffShadow >> 24); // write 8-bit
    1091                    bsBuffShadow <<= 8;
    1092                    bsLiveShadow -= 8;
    1093                }
    1094                // bsBuffShadow |= 0 << (32 - bsLiveShadow - 1);
    1095                bsLiveShadow++;
    1096            }
    1097        }
    1098
    1099        this.bsBuff = bsBuffShadow;
    1100        this.bsLive = bsLiveShadow;
    1101    }
    1102
    1103    private void sendMTFValues7() throws IOException {
    1104        final Data dataShadow = this.data;
    1105        final byte[][] len = dataShadow.sendMTFValues_len;
    1106        final int[][] code = dataShadow.sendMTFValues_code;
    1107        final OutputStream outShadow = this.out;
    1108        final byte[] selector = dataShadow.selector;
    1109        final char[] sfmap = dataShadow.sfmap;
    1110        final int nMTFShadow = this.nMTF;
    1111
    1112        int selCtr = 0;
    1113
    1114        int bsLiveShadow = this.bsLive;
    1115        int bsBuffShadow = this.bsBuff;
    1116
    1117        for (int gs = 0; gs < nMTFShadow;) {
    1118            final int ge = Math.min(gs + G_SIZE - 1, nMTFShadow - 1);
    1119            final int selector_selCtr = selector[selCtr] & 0xff;
    1120            final int[] code_selCtr = code[selector_selCtr];
    1121            final byte[] len_selCtr = len[selector_selCtr];
    1122
    1123            while (gs <= ge) {
    1124                final int sfmap_i = sfmap[gs];
    1125
    1126                //
    1127                // inlined: bsW(len_selCtr[sfmap_i] & 0xff,
    1128                // code_selCtr[sfmap_i]);
    1129                //
    1130                while (bsLiveShadow >= 8) {
    1131                    outShadow.write(bsBuffShadow >> 24);
    1132                    bsBuffShadow <<= 8;
    1133                    bsLiveShadow -= 8;
    1134                }
    1135                final int n = len_selCtr[sfmap_i] & 0xFF;
    1136                bsBuffShadow |= code_selCtr[sfmap_i] << 32 - bsLiveShadow - n;
    1137                bsLiveShadow += n;
    1138
    1139                gs++;
    1140            }
    1141
    1142            gs = ge + 1;
    1143            selCtr++;
    1144        }
    1145
    1146        this.bsBuff = bsBuffShadow;
    1147        this.bsLive = bsLiveShadow;
    1148    }
    1149
    1150    @Override
    1151    public void write(final byte[] buf, int offs, final int len) throws IOException {
    1152        if (offs < 0) {
    1153            throw new IndexOutOfBoundsException("offs(" + offs + ") < 0.");
    1154        }
    1155        if (len < 0) {
    1156            throw new IndexOutOfBoundsException("len(" + len + ") < 0.");
    1157        }
    1158        if (offs + len > buf.length) {
    1159            throw new IndexOutOfBoundsException("offs(" + offs + ") + len(" + len + ") > buf.length(" + buf.length + ").");
    1160        }
    1161        checkOpen();
    1162        for (final int hi = offs + len; offs < hi;) {
    1163            write0(buf[offs++]);
    1164        }
    1165    }
    1166
    1167    @Override
    1168    public void write(final int b) throws IOException {
    1169        checkOpen();
    1170        write0(b);
    1171    }
    1172
    1173    /**
    1174     * Keeps track of the last bytes written and implicitly performs run-length encoding as the first step of the bzip2 algorithm.
    1175     */
    1176    private void write0(int b) throws IOException {
    1177        if (this.currentChar != -1) {
    1178            b &= 0xff;
    1179            if (this.currentChar == b) {
    1180                if (++this.runLength > 254) {
    1181                    writeRun();
    1182                    this.currentChar = -1;
    1183                    this.runLength = 0;
    1184                }
    1185                // else nothing to do
    1186            } else {
    1187                writeRun();
    1188                this.runLength = 1;
    1189                this.currentChar = b;
    1190            }
    1191        } else {
    1192            this.currentChar = b & 0xff;
    1193            this.runLength++;
    1194        }
    1195    }
    1196
    1197    /**
    1198     * Writes the current byte to the buffer, run-length encoding it if it has been repeated at least four times (the first step RLEs sequences of four
    1199     * identical bytes).
    1200     *
    1201     * <p>
    1202     * Flushes the current block before writing data if it is full.
    1203     * </p>
    1204     *
    1205     * <p>
    1206     * "write to the buffer" means adding to data.buffer starting two steps "after" this.last - initially starting at index 1 (not 0) - and updating this.last
    1207     * to point to the last index written minus 1.
    1208     * </p>
    1209     */
    1210    private void writeRun() throws IOException {
    1211        final int lastShadow = this.last;
    1212
    1213        if (lastShadow < this.allowableBlockSize) {
    1214            final int currentCharShadow = this.currentChar;
    1215            final Data dataShadow = this.data;
    1216            dataShadow.inUse[currentCharShadow] = true;
    1217            final byte ch = (byte) currentCharShadow;
    1218
    1219            int runLengthShadow = this.runLength;
    1220            this.crc.update(currentCharShadow, runLengthShadow);
    1221
    1222            switch (runLengthShadow) {
    1223            case 1:
    1224                dataShadow.block[lastShadow + 2] = ch;
    1225                this.last = lastShadow + 1;
    1226                break;
    1227
    1228            case 2:
    1229                dataShadow.block[lastShadow + 2] = ch;
    1230                dataShadow.block[lastShadow + 3] = ch;
    1231                this.last = lastShadow + 2;
    1232                break;
    1233
    1234            case 3: {
    1235                final byte[] block = dataShadow.block;
    1236                block[lastShadow + 2] = ch;
    1237                block[lastShadow + 3] = ch;
    1238                block[lastShadow + 4] = ch;
    1239                this.last = lastShadow + 3;
    1240            }
    1241                break;
    1242
    1243            default: {
    1244                runLengthShadow -= 4;
    1245                dataShadow.inUse[runLengthShadow] = true;
    1246                final byte[] block = dataShadow.block;
    1247                block[lastShadow + 2] = ch;
    1248                block[lastShadow + 3] = ch;
    1249                block[lastShadow + 4] = ch;
    1250                block[lastShadow + 5] = ch;
    1251                block[lastShadow + 6] = (byte) runLengthShadow;
    1252                this.last = lastShadow + 5;
    1253            }
    1254                break;
    1255
    1256            }
    1257        } else {
    1258            endBlock();
    1259            initBlock();
    1260            writeRun();
    1261        }
    1262    }
    1263
    1264}