    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 * http://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;
    023
    024import org.apache.commons.compress.compressors.CompressorOutputStream;
    025
    026/**
    027 * An output stream that compresses into the BZip2 format into another stream.
    028 *
    029 * <p>
    030 * The compression requires large amounts of memory. Thus you should call the
    031 * {@link #close() close()} method as soon as possible, to force
    032 * {@code BZip2CompressorOutputStream} to release the allocated memory.
    033 * </p>
    034 *
    035 * <p> You can shrink the amount of allocated memory and maybe raise
    036 * the compression speed by choosing a lower blocksize, which in turn
    037 * may cause a lower compression ratio. You can avoid unnecessary
    038 * memory allocation by avoiding using a blocksize which is bigger
    039 * than the size of the input.  </p>
    040 *
    041 * <p> You can compute the memory usage for compressing by the
    042 * following formula: </p>
    043 *
    044 * <pre>
    045 * &lt;code&gt;400k + (9 * blocksize)&lt;/code&gt;.
    046 * </pre>
    047 *
    048 * <p> To get the memory required for decompression by {@link
    049 * BZip2CompressorInputStream} use </p>
    050 *
    051 * <pre>
    052 * &lt;code&gt;65k + (5 * blocksize)&lt;/code&gt;.
    053 * </pre>
    054 *
    055 * <table width="100%" border="1" summary="Memory usage by blocksize">
    056 * <tr>
    057 * <th colspan="3">Memory usage by blocksize</th>
    058 * </tr>
    059 * <tr>
    060 * <th align="right">Blocksize</th> <th align="right">Compression<br>
    061 * memory usage</th> <th align="right">Decompression<br>
    062 * memory usage</th>
    063 * </tr>
    064 * <tr>
    065 * <td align="right">100k</td>
    066 * <td align="right">1300k</td>
    067 * <td align="right">565k</td>
    068 * </tr>
    069 * <tr>
    070 * <td align="right">200k</td>
    071 * <td align="right">2200k</td>
    072 * <td align="right">1065k</td>
    073 * </tr>
    074 * <tr>
    075 * <td align="right">300k</td>
    076 * <td align="right">3100k</td>
    077 * <td align="right">1565k</td>
    078 * </tr>
    079 * <tr>
    080 * <td align="right">400k</td>
    081 * <td align="right">4000k</td>
    082 * <td align="right">2065k</td>
    083 * </tr>
    084 * <tr>
    085 * <td align="right">500k</td>
    086 * <td align="right">4900k</td>
    087 * <td align="right">2565k</td>
    088 * </tr>
    089 * <tr>
    090 * <td align="right">600k</td>
    091 * <td align="right">5800k</td>
    092 * <td align="right">3065k</td>
    093 * </tr>
    094 * <tr>
    095 * <td align="right">700k</td>
    096 * <td align="right">6700k</td>
    097 * <td align="right">3565k</td>
    098 * </tr>
    099 * <tr>
    100 * <td align="right">800k</td>
    101 * <td align="right">7600k</td>
    102 * <td align="right">4065k</td>
    103 * </tr>
    104 * <tr>
    105 * <td align="right">900k</td>
    106 * <td align="right">8500k</td>
    107 * <td align="right">4565k</td>
    108 * </tr>
    109 * </table>
    110 *
    111 * <p>
    112 * For decompression {@code BZip2CompressorInputStream} allocates less memory if the
    113 * bzipped input is smaller than one block.
    114 * </p>
    115 *
    116 * <p>
    117 * Instances of this class are not threadsafe.
    118 * </p>
    119 *
    120 * <p>
    121 * TODO: Update to BZip2 1.0.1
    122 * </p>
    123 * @NotThreadSafe
    124 */
    125public class BZip2CompressorOutputStream extends CompressorOutputStream
    126    implements BZip2Constants {
    127
    128    /**
    129     * The minimum supported blocksize {@code  == 1}.
    130     */
    131    public static final int MIN_BLOCKSIZE = 1;
    132
    133    /**
    134     * The maximum supported blocksize {@code  == 9}.
    135     */
    136    public static final int MAX_BLOCKSIZE = 9;
    137
    138    private static final int GREATER_ICOST = 15;
    139    private static final int LESSER_ICOST = 0;
    140
    141    private static void hbMakeCodeLengths(final byte[] len, final int[] freq,
    142                                          final Data dat, final int alphaSize,
    143                                          final int maxLen) {
    144        /*
    145         * Nodes and heap entries run from 1. Entry 0 for both the heap and
    146         * nodes is a sentinel.
    147         */
    148        final int[] heap = dat.heap;
    149        final int[] weight = dat.weight;
    150        final int[] parent = dat.parent;
    151
    152        for (int i = alphaSize; --i >= 0;) {
    153            weight[i + 1] = (freq[i] == 0 ? 1 : freq[i]) << 8;
    154        }
    155
    156        for (boolean tooLong = true; tooLong;) {
    157            tooLong = false;
    158
    159            int nNodes = alphaSize;
    160            int nHeap = 0;
    161            heap[0] = 0;
    162            weight[0] = 0;
    163            parent[0] = -2;
    164
    165            for (int i = 1; i <= alphaSize; i++) {
    166                parent[i] = -1;
    167                nHeap++;
    168                heap[nHeap] = i;
    169
    170                int zz = nHeap;
    171                final int tmp = heap[zz];
    172                while (weight[tmp] < weight[heap[zz >> 1]]) {
    173                    heap[zz] = heap[zz >> 1];
    174                    zz >>= 1;
    175                }
    176                heap[zz] = tmp;
    177            }
    178
    179            while (nHeap > 1) {
    180                final int n1 = heap[1];
    181                heap[1] = heap[nHeap];
    182                nHeap--;
    183
    184                int yy = 0;
    185                int zz = 1;
    186                int tmp = heap[1];
    187
    188                while (true) {
    189                    yy = zz << 1;
    190
    191                    if (yy > nHeap) {
    192                        break;
    193                    }
    194
    195                    if ((yy < nHeap)
    196                        && (weight[heap[yy + 1]] < weight[heap[yy]])) {
    197                        yy++;
    198                    }
    199
    200                    if (weight[tmp] < weight[heap[yy]]) {
    201                        break;
    202                    }
    203
    204                    heap[zz] = heap[yy];
    205                    zz = yy;
    206                }
    207
    208                heap[zz] = tmp;
    209
    210                final int n2 = heap[1];
    211                heap[1] = heap[nHeap];
    212                nHeap--;
    213
    214                yy = 0;
    215                zz = 1;
    216                tmp = heap[1];
    217
    218                while (true) {
    219                    yy = zz << 1;
    220
    221                    if (yy > nHeap) {
    222                        break;
    223                    }
    224
    225                    if ((yy < nHeap)
    226                        && (weight[heap[yy + 1]] < weight[heap[yy]])) {
    227                        yy++;
    228                    }
    229
    230                    if (weight[tmp] < weight[heap[yy]]) {
    231                        break;
    232                    }
    233
    234                    heap[zz] = heap[yy];
    235                    zz = yy;
    236                }
    237
    238                heap[zz] = tmp;
    239                nNodes++;
    240                parent[n1] = parent[n2] = nNodes;
    241
    242                final int weight_n1 = weight[n1];
    243                final int weight_n2 = weight[n2];
    244                weight[nNodes] = ((weight_n1 & 0xffffff00)
    245                                  + (weight_n2 & 0xffffff00))
    246                    | (1 + (((weight_n1 & 0x000000ff)
    247                             > (weight_n2 & 0x000000ff))
    248                            ? (weight_n1 & 0x000000ff)
    249                            : (weight_n2 & 0x000000ff)));
    250
    251                parent[nNodes] = -1;
    252                nHeap++;
    253                heap[nHeap] = nNodes;
    254
    255                tmp = 0;
    256                zz = nHeap;
    257                tmp = heap[zz];
    258                final int weight_tmp = weight[tmp];
    259                while (weight_tmp < weight[heap[zz >> 1]]) {
    260                    heap[zz] = heap[zz >> 1];
    261                    zz >>= 1;
    262                }
    263                heap[zz] = tmp;
    264
    265            }
    266
    267            for (int i = 1; i <= alphaSize; i++) {
    268                int j = 0;
    269                int k = i;
    270
    271                for (int parent_k; (parent_k = parent[k]) >= 0;) {
    272                    k = parent_k;
    273                    j++;
    274                }
    275
    276                len[i - 1] = (byte) j;
    277                if (j > maxLen) {
    278                    tooLong = true;
    279                }
    280            }
    281
    282            if (tooLong) {
    283                for (int i = 1; i < alphaSize; i++) {
    284                    int j = weight[i] >> 8;
    285                    j = 1 + (j >> 1);
    286                    weight[i] = j << 8;
    287                }
    288            }
    289        }
    290    }
    291
    292    /**
    293     * Index of the last char in the block, so the block size == last + 1.
    294     */
    295    private int last;
    296
    297    /**
    298     * Always: in the range 0 .. 9. The current block size is 100000 * this
    299     * number.
    300     */
    301    private final int blockSize100k;
    302
    303    private int bsBuff;
    304    private int bsLive;
    305    private final CRC crc = new CRC();
    306
    307    private int nInUse;
    308
    309    private int nMTF;
    310
    311    private int currentChar = -1;
    312    private int runLength = 0;
    313
    314    private int blockCRC;
    315    private int combinedCRC;
    316    private final int allowableBlockSize;
    317
    318    /**
    319     * All memory intensive stuff.
    320     */
    321    private Data data;
    322    private BlockSort blockSorter;
    323
    324    private OutputStream out;
    325    private volatile boolean closed;
    326
    327    /**
    328     * Chooses a blocksize based on the given length of the data to compress.
    329     *
    330     * @return The blocksize, between {@link #MIN_BLOCKSIZE} and
    331     *         {@link #MAX_BLOCKSIZE} both inclusive. For a negative
    332     *         {@code inputLength} this method returns {@code MAX_BLOCKSIZE}
    333     *         always.
    334     *
    335     * @param inputLength
    336     *            The length of the data which will be compressed by
    337     *            {@code BZip2CompressorOutputStream}.
    338     */
    339    public static int chooseBlockSize(final long inputLength) {
    340        return (inputLength > 0) ? (int) Math
    341            .min((inputLength / 132000) + 1, 9) : MAX_BLOCKSIZE;
    342    }
    343
    344    /**
    345     * Constructs a new {@code BZip2CompressorOutputStream} with a blocksize of 900k.
    346     *
    347     * @param out
    348     *            the destination stream.
    349     *
    350     * @throws IOException
    351     *             if an I/O error occurs in the specified stream.
    352     * @throws NullPointerException
    353     *             if <code>out == null</code>.
    354     */
    355    public BZip2CompressorOutputStream(final OutputStream out)
    356        throws IOException {
    357        this(out, MAX_BLOCKSIZE);
    358    }
    359
    360    /**
    361     * Constructs a new {@code BZip2CompressorOutputStream} with specified blocksize.
    362     *
    363     * @param out
    364     *            the destination stream.
    365     * @param blockSize
    366     *            the blockSize as 100k units.
    367     *
    368     * @throws IOException
    369     *             if an I/O error occurs in the specified stream.
    370     * @throws IllegalArgumentException
    371     *             if <code>(blockSize &lt; 1) || (blockSize &gt; 9)</code>.
    372     * @throws NullPointerException
    373     *             if <code>out == null</code>.
    374     *
    375     * @see #MIN_BLOCKSIZE
    376     * @see #MAX_BLOCKSIZE
    377     */
    378    public BZip2CompressorOutputStream(final OutputStream out, final int blockSize) throws IOException {
    379        if (blockSize < 1) {
    380            throw new IllegalArgumentException("blockSize(" + blockSize + ") < 1");
    381        }
    382        if (blockSize > 9) {
    383            throw new IllegalArgumentException("blockSize(" + blockSize + ") > 9");
    384        }
    385
    386        this.blockSize100k = blockSize;
    387        this.out = out;
    388
    389        /* 20 is just a paranoia constant */
    390        this.allowableBlockSize = (this.blockSize100k * BZip2Constants.BASEBLOCKSIZE) - 20;
    391        init();
    392    }
    393
    394    @Override
    395    public void write(final int b) throws IOException {
    396        if (!closed) {
    397            write0(b);
    398        } else {
    399            throw new IOException("closed");
    400        }
    401    }
    402
    403    /**
    404     * Writes the current byte to the buffer, run-length encoding it
    405     * if it has been repeated at least four times (the first step
    406     * RLEs sequences of four identical bytes).
    407     *
    408     * <p>Flushes the current block before writing data if it is
    409     * full.</p>
    410     *
    411     * <p>"write to the buffer" means adding to data.buffer starting
    412     * two steps "after" this.last - initially starting at index 1
    413     * (not 0) - and updating this.last to point to the last index
    414     * written minus 1.</p>
    415     */
    416    private void writeRun() throws IOException {
    417        final int lastShadow = this.last;
    418
    419        if (lastShadow < this.allowableBlockSize) {
    420            final int currentCharShadow = this.currentChar;
    421            final Data dataShadow = this.data;
    422            dataShadow.inUse[currentCharShadow] = true;
    423            final byte ch = (byte) currentCharShadow;
    424
    425            int runLengthShadow = this.runLength;
    426            this.crc.updateCRC(currentCharShadow, runLengthShadow);
    427
    428            switch (runLengthShadow) {
    429            case 1:
    430                dataShadow.block[lastShadow + 2] = ch;
    431                this.last = lastShadow + 1;
    432                break;
    433
    434            case 2:
    435                dataShadow.block[lastShadow + 2] = ch;
    436                dataShadow.block[lastShadow + 3] = ch;
    437                this.last = lastShadow + 2;
    438                break;
    439
    440            case 3: {
    441                final byte[] block = dataShadow.block;
    442                block[lastShadow + 2] = ch;
    443                block[lastShadow + 3] = ch;
    444                block[lastShadow + 4] = ch;
    445                this.last = lastShadow + 3;
    446            }
    447                break;
    448
    449            default: {
    450                runLengthShadow -= 4;
    451                dataShadow.inUse[runLengthShadow] = true;
    452                final byte[] block = dataShadow.block;
    453                block[lastShadow + 2] = ch;
    454                block[lastShadow + 3] = ch;
    455                block[lastShadow + 4] = ch;
    456                block[lastShadow + 5] = ch;
    457                block[lastShadow + 6] = (byte) runLengthShadow;
    458                this.last = lastShadow + 5;
    459            }
    460                break;
    461
    462            }
    463        } else {
    464            endBlock();
    465            initBlock();
    466            writeRun();
    467        }
    468    }
    469
    470    /**
    471     * Overriden to warn about an unclosed stream.
    472     */
    473    @Override
    474    protected void finalize() throws Throwable {
    475        if (!closed) {
    476            System.err.println("Unclosed BZip2CompressorOutputStream detected, will *not* close it");
    477        }
    478        super.finalize();
    479    }
    480
    481
    482    public void finish() throws IOException {
    483        if (!closed) {
    484            closed = true;
    485            try {
    486                if (this.runLength > 0) {
    487                    writeRun();
    488                }
    489                this.currentChar = -1;
    490                endBlock();
    491                endCompression();
    492            } finally {
    493                this.out = null;
    494                this.blockSorter = null;
    495                this.data = null;
    496            }
    497        }
    498    }
    499
    500    @Override
    501    public void close() throws IOException {
    502        if (!closed) {
    503            final OutputStream outShadow = this.out;
    504            finish();
    505            outShadow.close();
    506        }
    507    }
    508
    509    @Override
    510    public void flush() throws IOException {
    511        final OutputStream outShadow = this.out;
    512        if (outShadow != null) {
    513            outShadow.flush();
    514        }
    515    }
    516
    517    /**
    518     * Writes magic bytes like BZ on the first position of the stream
    519     * and bytes indiciating the file-format, which is
    520     * huffmanised, followed by a digit indicating blockSize100k.
    521     * @throws IOException if the magic bytes could not been written
    522     */
    523    private void init() throws IOException {
    524        bsPutUByte('B');
    525        bsPutUByte('Z');
    526
    527        this.data = new Data(this.blockSize100k);
    528        this.blockSorter = new BlockSort(this.data);
    529
    530        // huffmanised magic bytes
    531        bsPutUByte('h');
    532        bsPutUByte('0' + this.blockSize100k);
    533
    534        this.combinedCRC = 0;
    535        initBlock();
    536    }
    537
    538    private void initBlock() {
    539        // blockNo++;
    540        this.crc.initialiseCRC();
    541        this.last = -1;
    542        // ch = 0;
    543
    544        final boolean[] inUse = this.data.inUse;
    545        for (int i = 256; --i >= 0;) {
    546            inUse[i] = false;
    547        }
    548
    549    }
    550
    551    private void endBlock() throws IOException {
    552        this.blockCRC = this.crc.getFinalCRC();
    553        this.combinedCRC = (this.combinedCRC << 1) | (this.combinedCRC >>> 31);
    554        this.combinedCRC ^= this.blockCRC;
    555
    556        // empty block at end of file
    557        if (this.last == -1) {
    558            return;
    559        }
    560
    561        /* sort the block and establish posn of original string */
    562        blockSort();
    563
    564        /*
    565         * A 6-byte block header, the value chosen arbitrarily as 0x314159265359
    566         * :-). A 32 bit value does not really give a strong enough guarantee
    567         * that the value will not appear by chance in the compressed
    568         * datastream. Worst-case probability of this event, for a 900k block,
    569         * is about 2.0e-3 for 32 bits, 1.0e-5 for 40 bits and 4.0e-8 for 48
    570         * bits. For a compressed file of size 100Gb -- about 100000 blocks --
    571         * only a 48-bit marker will do. NB: normal compression/ decompression
    572         * donot rely on these statistical properties. They are only important
    573         * when trying to recover blocks from damaged files.
    574         */
    575        bsPutUByte(0x31);
    576        bsPutUByte(0x41);
    577        bsPutUByte(0x59);
    578        bsPutUByte(0x26);
    579        bsPutUByte(0x53);
    580        bsPutUByte(0x59);
    581
    582        /* Now the block's CRC, so it is in a known place. */
    583        bsPutInt(this.blockCRC);
    584
    585        /* Now a single bit indicating no randomisation. */
    586        bsW(1, 0);
    587
    588        /* Finally, block's contents proper. */
    589        moveToFrontCodeAndSend();
    590    }
    591
    592    private void endCompression() throws IOException {
    593        /*
    594         * Now another magic 48-bit number, 0x177245385090, to indicate the end
    595         * of the last block. (sqrt(pi), if you want to know. I did want to use
    596         * e, but it contains too much repetition -- 27 18 28 18 28 46 -- for me
    597         * to feel statistically comfortable. Call me paranoid.)
    598         */
    599        bsPutUByte(0x17);
    600        bsPutUByte(0x72);
    601        bsPutUByte(0x45);
    602        bsPutUByte(0x38);
    603        bsPutUByte(0x50);
    604        bsPutUByte(0x90);
    605
    606        bsPutInt(this.combinedCRC);
    607        bsFinishedWithStream();
    608    }
    609
    610    /**
    611     * Returns the blocksize parameter specified at construction time.
    612     * @return the blocksize parameter specified at construction time
    613     */
    614    public final int getBlockSize() {
    615        return this.blockSize100k;
    616    }
    617
    618    @Override
    619    public void write(final byte[] buf, int offs, final int len)
    620        throws IOException {
    621        if (offs < 0) {
    622            throw new IndexOutOfBoundsException("offs(" + offs + ") < 0.");
    623        }
    624        if (len < 0) {
    625            throw new IndexOutOfBoundsException("len(" + len + ") < 0.");
    626        }
    627        if (offs + len > buf.length) {
    628            throw new IndexOutOfBoundsException("offs(" + offs + ") + len("
    629                                                + len + ") > buf.length("
    630                                                + buf.length + ").");
    631        }
    632        if (closed) {
    633            throw new IOException("stream closed");
    634        }
    635
    636        for (final int hi = offs + len; offs < hi;) {
    637            write0(buf[offs++]);
    638        }
    639    }
    640
    641    /**
    642     * Keeps track of the last bytes written and implicitly performs
    643     * run-length encoding as the first step of the bzip2 algorithm.
    644     */
    645    private void write0(int b) throws IOException {
    646        if (this.currentChar != -1) {
    647            b &= 0xff;
    648            if (this.currentChar == b) {
    649                if (++this.runLength > 254) {
    650                    writeRun();
    651                    this.currentChar = -1;
    652                    this.runLength = 0;
    653                }
    654                // else nothing to do
    655            } else {
    656                writeRun();
    657                this.runLength = 1;
    658                this.currentChar = b;
    659            }
    660        } else {
    661            this.currentChar = b & 0xff;
    662            this.runLength++;
    663        }
    664    }
    665
    666    private static void hbAssignCodes(final int[] code, final byte[] length,
    667                                      final int minLen, final int maxLen,
    668                                      final int alphaSize) {
    669        int vec = 0;
    670        for (int n = minLen; n <= maxLen; n++) {
    671            for (int i = 0; i < alphaSize; i++) {
    672                if ((length[i] & 0xff) == n) {
    673                    code[i] = vec;
    674                    vec++;
    675                }
    676            }
    677            vec <<= 1;
    678        }
    679    }
    680
    681    private void bsFinishedWithStream() throws IOException {
    682        while (this.bsLive > 0) {
    683            final int ch = this.bsBuff >> 24;
    684            this.out.write(ch); // write 8-bit
    685            this.bsBuff <<= 8;
    686            this.bsLive -= 8;
    687        }
    688    }
    689
    690    private void bsW(final int n, final int v) throws IOException {
    691        final OutputStream outShadow = this.out;
    692        int bsLiveShadow = this.bsLive;
    693        int bsBuffShadow = this.bsBuff;
    694
    695        while (bsLiveShadow >= 8) {
    696            outShadow.write(bsBuffShadow >> 24); // write 8-bit
    697            bsBuffShadow <<= 8;
    698            bsLiveShadow -= 8;
    699        }
    700
    701        this.bsBuff = bsBuffShadow | (v << (32 - bsLiveShadow - n));
    702        this.bsLive = bsLiveShadow + n;
    703    }
    704
    705    private void bsPutUByte(final int c) throws IOException {
    706        bsW(8, c);
    707    }
    708
    709    private void bsPutInt(final int u) throws IOException {
    710        bsW(8, (u >> 24) & 0xff);
    711        bsW(8, (u >> 16) & 0xff);
    712        bsW(8, (u >> 8) & 0xff);
    713        bsW(8, u & 0xff);
    714    }
    715
    716    private void sendMTFValues() throws IOException {
    717        final byte[][] len = this.data.sendMTFValues_len;
    718        final int alphaSize = this.nInUse + 2;
    719
    720        for (int t = N_GROUPS; --t >= 0;) {
    721            final byte[] len_t = len[t];
    722            for (int v = alphaSize; --v >= 0;) {
    723                len_t[v] = GREATER_ICOST;
    724            }
    725        }
    726
    727        /* Decide how many coding tables to use */
    728        // assert (this.nMTF > 0) : this.nMTF;
    729        final int nGroups = (this.nMTF < 200) ? 2 : (this.nMTF < 600) ? 3
    730            : (this.nMTF < 1200) ? 4 : (this.nMTF < 2400) ? 5 : 6;
    731
    732        /* Generate an initial set of coding tables */
    733        sendMTFValues0(nGroups, alphaSize);
    734
    735        /*
    736         * Iterate up to N_ITERS times to improve the tables.
    737         */
    738        final int nSelectors = sendMTFValues1(nGroups, alphaSize);
    739
    740        /* Compute MTF values for the selectors. */
    741        sendMTFValues2(nGroups, nSelectors);
    742
    743        /* Assign actual codes for the tables. */
    744        sendMTFValues3(nGroups, alphaSize);
    745
    746        /* Transmit the mapping table. */
    747        sendMTFValues4();
    748
    749        /* Now the selectors. */
    750        sendMTFValues5(nGroups, nSelectors);
    751
    752        /* Now the coding tables. */
    753        sendMTFValues6(nGroups, alphaSize);
    754
    755        /* And finally, the block data proper */
    756        sendMTFValues7();
    757    }
    758
    759    private void sendMTFValues0(final int nGroups, final int alphaSize) {
    760        final byte[][] len = this.data.sendMTFValues_len;
    761        final int[] mtfFreq = this.data.mtfFreq;
    762
    763        int remF = this.nMTF;
    764        int gs = 0;
    765
    766        for (int nPart = nGroups; nPart > 0; nPart--) {
    767            final int tFreq = remF / nPart;
    768            int ge = gs - 1;
    769            int aFreq = 0;
    770
    771            for (final int a = alphaSize - 1; (aFreq < tFreq) && (ge < a);) {
    772                aFreq += mtfFreq[++ge];
    773            }
    774
    775            if ((ge > gs) && (nPart != nGroups) && (nPart != 1)
    776                && (((nGroups - nPart) & 1) != 0)) {
    777                aFreq -= mtfFreq[ge--];
    778            }
    779
    780            final byte[] len_np = len[nPart - 1];
    781            for (int v = alphaSize; --v >= 0;) {
    782                if ((v >= gs) && (v <= ge)) {
    783                    len_np[v] = LESSER_ICOST;
    784                } else {
    785                    len_np[v] = GREATER_ICOST;
    786                }
    787            }
    788
    789            gs = ge + 1;
    790            remF -= aFreq;
    791        }
    792    }
    793
    794    private int sendMTFValues1(final int nGroups, final int alphaSize) {
    795        final Data dataShadow = this.data;
    796        final int[][] rfreq = dataShadow.sendMTFValues_rfreq;
    797        final int[] fave = dataShadow.sendMTFValues_fave;
    798        final short[] cost = dataShadow.sendMTFValues_cost;
    799        final char[] sfmap = dataShadow.sfmap;
    800        final byte[] selector = dataShadow.selector;
    801        final byte[][] len = dataShadow.sendMTFValues_len;
    802        final byte[] len_0 = len[0];
    803        final byte[] len_1 = len[1];
    804        final byte[] len_2 = len[2];
    805        final byte[] len_3 = len[3];
    806        final byte[] len_4 = len[4];
    807        final byte[] len_5 = len[5];
    808        final int nMTFShadow = this.nMTF;
    809
    810        int nSelectors = 0;
    811
    812        for (int iter = 0; iter < N_ITERS; iter++) {
    813            for (int t = nGroups; --t >= 0;) {
    814                fave[t] = 0;
    815                final int[] rfreqt = rfreq[t];
    816                for (int i = alphaSize; --i >= 0;) {
    817                    rfreqt[i] = 0;
    818                }
    819            }
    820
    821            nSelectors = 0;
    822
    823            for (int gs = 0; gs < this.nMTF;) {
    824                /* Set group start & end marks. */
    825
    826                /*
    827                 * Calculate the cost of this group as coded by each of the
    828                 * coding tables.
    829                 */
    830
    831                final int ge = Math.min(gs + G_SIZE - 1, nMTFShadow - 1);
    832
    833                if (nGroups == N_GROUPS) {
    834                    // unrolled version of the else-block
    835
    836                    short cost0 = 0;
    837                    short cost1 = 0;
    838                    short cost2 = 0;
    839                    short cost3 = 0;
    840                    short cost4 = 0;
    841                    short cost5 = 0;
    842
    843                    for (int i = gs; i <= ge; i++) {
    844                        final int icv = sfmap[i];
    845                        cost0 += len_0[icv] & 0xff;
    846                        cost1 += len_1[icv] & 0xff;
    847                        cost2 += len_2[icv] & 0xff;
    848                        cost3 += len_3[icv] & 0xff;
    849                        cost4 += len_4[icv] & 0xff;
    850                        cost5 += len_5[icv] & 0xff;
    851                    }
    852
    853                    cost[0] = cost0;
    854                    cost[1] = cost1;
    855                    cost[2] = cost2;
    856                    cost[3] = cost3;
    857                    cost[4] = cost4;
    858                    cost[5] = cost5;
    859
    860                } else {
    861                    for (int t = nGroups; --t >= 0;) {
    862                        cost[t] = 0;
    863                    }
    864
    865                    for (int i = gs; i <= ge; i++) {
    866                        final int icv = sfmap[i];
    867                        for (int t = nGroups; --t >= 0;) {
    868                            cost[t] += len[t][icv] & 0xff;
    869                        }
    870                    }
    871                }
    872
    873                /*
    874                 * Find the coding table which is best for this group, and
    875                 * record its identity in the selector table.
    876                 */
    877                int bt = -1;
    878                for (int t = nGroups, bc = 999999999; --t >= 0;) {
    879                    final int cost_t = cost[t];
    880                    if (cost_t < bc) {
    881                        bc = cost_t;
    882                        bt = t;
    883                    }
    884                }
    885
    886                fave[bt]++;
    887                selector[nSelectors] = (byte) bt;
    888                nSelectors++;
    889
    890                /*
    891                 * Increment the symbol frequencies for the selected table.
    892                 */
    893                final int[] rfreq_bt = rfreq[bt];
    894                for (int i = gs; i <= ge; i++) {
    895                    rfreq_bt[sfmap[i]]++;
    896                }
    897
    898                gs = ge + 1;
    899            }
    900
    901            /*
    902             * Recompute the tables based on the accumulated frequencies.
    903             */
    904            for (int t = 0; t < nGroups; t++) {
    905                hbMakeCodeLengths(len[t], rfreq[t], this.data, alphaSize, 20);
    906            }
    907        }
    908
    909        return nSelectors;
    910    }
    911
    912    private void sendMTFValues2(final int nGroups, final int nSelectors) {
    913        // assert (nGroups < 8) : nGroups;
    914
    915        final Data dataShadow = this.data;
    916        final byte[] pos = dataShadow.sendMTFValues2_pos;
    917
    918        for (int i = nGroups; --i >= 0;) {
    919            pos[i] = (byte) i;
    920        }
    921
    922        for (int i = 0; i < nSelectors; i++) {
    923            final byte ll_i = dataShadow.selector[i];
    924            byte tmp = pos[0];
    925            int j = 0;
    926
    927            while (ll_i != tmp) {
    928                j++;
    929                final byte tmp2 = tmp;
    930                tmp = pos[j];
    931                pos[j] = tmp2;
    932            }
    933
    934            pos[0] = tmp;
    935            dataShadow.selectorMtf[i] = (byte) j;
    936        }
    937    }
    938
    939    private void sendMTFValues3(final int nGroups, final int alphaSize) {
    940        final int[][] code = this.data.sendMTFValues_code;
    941        final byte[][] len = this.data.sendMTFValues_len;
    942
    943        for (int t = 0; t < nGroups; t++) {
    944            int minLen = 32;
    945            int maxLen = 0;
    946            final byte[] len_t = len[t];
    947            for (int i = alphaSize; --i >= 0;) {
    948                final int l = len_t[i] & 0xff;
    949                if (l > maxLen) {
    950                    maxLen = l;
    951                }
    952                if (l < minLen) {
    953                    minLen = l;
    954                }
    955            }
    956
    957            // assert (maxLen <= 20) : maxLen;
    958            // assert (minLen >= 1) : minLen;
    959
    960            hbAssignCodes(code[t], len[t], minLen, maxLen, alphaSize);
    961        }
    962    }
    963
    964    private void sendMTFValues4() throws IOException {
    965        final boolean[] inUse = this.data.inUse;
    966        final boolean[] inUse16 = this.data.sentMTFValues4_inUse16;
    967
    968        for (int i = 16; --i >= 0;) {
    969            inUse16[i] = false;
    970            final int i16 = i * 16;
    971            for (int j = 16; --j >= 0;) {
    972                if (inUse[i16 + j]) {
    973                    inUse16[i] = true;
    974                }
    975            }
    976        }
    977
    978        for (int i = 0; i < 16; i++) {
    979            bsW(1, inUse16[i] ? 1 : 0);
    980        }
    981
    982        final OutputStream outShadow = this.out;
    983        int bsLiveShadow = this.bsLive;
    984        int bsBuffShadow = this.bsBuff;
    985
    986        for (int i = 0; i < 16; i++) {
    987            if (inUse16[i]) {
    988                final int i16 = i * 16;
    989                for (int j = 0; j < 16; j++) {
    990                    // inlined: bsW(1, inUse[i16 + j] ? 1 : 0);
    991                    while (bsLiveShadow >= 8) {
    992                        outShadow.write(bsBuffShadow >> 24); // write 8-bit
    993                        bsBuffShadow <<= 8;
    994                        bsLiveShadow -= 8;
    995                    }
    996                    if (inUse[i16 + j]) {
    997                        bsBuffShadow |= 1 << (32 - bsLiveShadow - 1);
    998                    }
    999                    bsLiveShadow++;
    1000                }
    1001            }
    1002        }
    1003
    1004        this.bsBuff = bsBuffShadow;
    1005        this.bsLive = bsLiveShadow;
    1006    }
    1007
    1008    private void sendMTFValues5(final int nGroups, final int nSelectors)
    1009        throws IOException {
    1010        bsW(3, nGroups);
    1011        bsW(15, nSelectors);
    1012
    1013        final OutputStream outShadow = this.out;
    1014        final byte[] selectorMtf = this.data.selectorMtf;
    1015
    1016        int bsLiveShadow = this.bsLive;
    1017        int bsBuffShadow = this.bsBuff;
    1018
    1019        for (int i = 0; i < nSelectors; i++) {
    1020            for (int j = 0, hj = selectorMtf[i] & 0xff; j < hj; j++) {
    1021                // inlined: bsW(1, 1);
    1022                while (bsLiveShadow >= 8) {
    1023                    outShadow.write(bsBuffShadow >> 24);
    1024                    bsBuffShadow <<= 8;
    1025                    bsLiveShadow -= 8;
    1026                }
    1027                bsBuffShadow |= 1 << (32 - bsLiveShadow - 1);
    1028                bsLiveShadow++;
    1029            }
    1030
    1031            // inlined: bsW(1, 0);
    1032            while (bsLiveShadow >= 8) {
    1033                outShadow.write(bsBuffShadow >> 24);
    1034                bsBuffShadow <<= 8;
    1035                bsLiveShadow -= 8;
    1036            }
    1037            // bsBuffShadow |= 0 << (32 - bsLiveShadow - 1);
    1038            bsLiveShadow++;
    1039        }
    1040
    1041        this.bsBuff = bsBuffShadow;
    1042        this.bsLive = bsLiveShadow;
    1043    }
    1044
    1045    private void sendMTFValues6(final int nGroups, final int alphaSize)
    1046        throws IOException {
    1047        final byte[][] len = this.data.sendMTFValues_len;
    1048        final OutputStream outShadow = this.out;
    1049
    1050        int bsLiveShadow = this.bsLive;
    1051        int bsBuffShadow = this.bsBuff;
    1052
    1053        for (int t = 0; t < nGroups; t++) {
    1054            final byte[] len_t = len[t];
    1055            int curr = len_t[0] & 0xff;
    1056
    1057            // inlined: bsW(5, curr);
    1058            while (bsLiveShadow >= 8) {
    1059                outShadow.write(bsBuffShadow >> 24); // write 8-bit
    1060                bsBuffShadow <<= 8;
    1061                bsLiveShadow -= 8;
    1062            }
    1063            bsBuffShadow |= curr << (32 - bsLiveShadow - 5);
    1064            bsLiveShadow += 5;
    1065
    1066            for (int i = 0; i < alphaSize; i++) {
    1067                final int lti = len_t[i] & 0xff;
    1068                while (curr < lti) {
    1069                    // inlined: bsW(2, 2);
    1070                    while (bsLiveShadow >= 8) {
    1071                        outShadow.write(bsBuffShadow >> 24); // write 8-bit
    1072                        bsBuffShadow <<= 8;
    1073                        bsLiveShadow -= 8;
    1074                    }
    1075                    bsBuffShadow |= 2 << (32 - bsLiveShadow - 2);
    1076                    bsLiveShadow += 2;
    1077
    1078                    curr++; /* 10 */
    1079                }
    1080
    1081                while (curr > lti) {
    1082                    // inlined: bsW(2, 3);
    1083                    while (bsLiveShadow >= 8) {
    1084                        outShadow.write(bsBuffShadow >> 24); // write 8-bit
    1085                        bsBuffShadow <<= 8;
    1086                        bsLiveShadow -= 8;
    1087                    }
    1088                    bsBuffShadow |= 3 << (32 - bsLiveShadow - 2);
    1089                    bsLiveShadow += 2;
    1090
    1091                    curr--; /* 11 */
    1092                }
    1093
    1094                // inlined: bsW(1, 0);
    1095                while (bsLiveShadow >= 8) {
    1096                    outShadow.write(bsBuffShadow >> 24); // write 8-bit
    1097                    bsBuffShadow <<= 8;
    1098                    bsLiveShadow -= 8;
    1099                }
    1100                // bsBuffShadow |= 0 << (32 - bsLiveShadow - 1);
    1101                bsLiveShadow++;
    1102            }
    1103        }
    1104
    1105        this.bsBuff = bsBuffShadow;
    1106        this.bsLive = bsLiveShadow;
    1107    }
    1108
    1109    private void sendMTFValues7() throws IOException {
    1110        final Data dataShadow = this.data;
    1111        final byte[][] len = dataShadow.sendMTFValues_len;
    1112        final int[][] code = dataShadow.sendMTFValues_code;
    1113        final OutputStream outShadow = this.out;
    1114        final byte[] selector = dataShadow.selector;
    1115        final char[] sfmap = dataShadow.sfmap;
    1116        final int nMTFShadow = this.nMTF;
    1117
    1118        int selCtr = 0;
    1119
    1120        int bsLiveShadow = this.bsLive;
    1121        int bsBuffShadow = this.bsBuff;
    1122
    1123        for (int gs = 0; gs < nMTFShadow;) {
    1124            final int ge = Math.min(gs + G_SIZE - 1, nMTFShadow - 1);
    1125            final int selector_selCtr = selector[selCtr] & 0xff;
    1126            final int[] code_selCtr = code[selector_selCtr];
    1127            final byte[] len_selCtr = len[selector_selCtr];
    1128
    1129            while (gs <= ge) {
    1130                final int sfmap_i = sfmap[gs];
    1131
    1132                //
    1133                // inlined: bsW(len_selCtr[sfmap_i] & 0xff,
    1134                // code_selCtr[sfmap_i]);
    1135                //
    1136                while (bsLiveShadow >= 8) {
    1137                    outShadow.write(bsBuffShadow >> 24);
    1138                    bsBuffShadow <<= 8;
    1139                    bsLiveShadow -= 8;
    1140                }
    1141                final int n = len_selCtr[sfmap_i] & 0xFF;
    1142                bsBuffShadow |= code_selCtr[sfmap_i] << (32 - bsLiveShadow - n);
    1143                bsLiveShadow += n;
    1144
    1145                gs++;
    1146            }
    1147
    1148            gs = ge + 1;
    1149            selCtr++;
    1150        }
    1151
    1152        this.bsBuff = bsBuffShadow;
    1153        this.bsLive = bsLiveShadow;
    1154    }
    1155
    1156    private void moveToFrontCodeAndSend() throws IOException {
    1157        bsW(24, this.data.origPtr);
    1158        generateMTFValues();
    1159        sendMTFValues();
    1160    }
    1161
    1162    private void blockSort() {
    1163        blockSorter.blockSort(data, last);
    1164    }
    1165
    1166    /*
    1167     * Performs Move-To-Front on the Burrows-Wheeler transformed
    1168     * buffer, storing the MTFed data in data.sfmap in RUNA/RUNB
    1169     * run-length-encoded form.
    1170     *
    1171     * <p>Keeps track of byte frequencies in data.mtfFreq at the same time.</p>
    1172     */
    1173    private void generateMTFValues() {
    1174        final int lastShadow = this.last;
    1175        final Data dataShadow = this.data;
    1176        final boolean[] inUse = dataShadow.inUse;
    1177        final byte[] block = dataShadow.block;
    1178        final int[] fmap = dataShadow.fmap;
    1179        final char[] sfmap = dataShadow.sfmap;
    1180        final int[] mtfFreq = dataShadow.mtfFreq;
    1181        final byte[] unseqToSeq = dataShadow.unseqToSeq;
    1182        final byte[] yy = dataShadow.generateMTFValues_yy;
    1183
    1184        // make maps
    1185        int nInUseShadow = 0;
    1186        for (int i = 0; i < 256; i++) {
    1187            if (inUse[i]) {
    1188                unseqToSeq[i] = (byte) nInUseShadow;
    1189                nInUseShadow++;
    1190            }
    1191        }
    1192        this.nInUse = nInUseShadow;
    1193
    1194        final int eob = nInUseShadow + 1;
    1195
    1196        for (int i = eob; i >= 0; i--) {
    1197            mtfFreq[i] = 0;
    1198        }
    1199
    1200        for (int i = nInUseShadow; --i >= 0;) {
    1201            yy[i] = (byte) i;
    1202        }
    1203
    1204        int wr = 0;
    1205        int zPend = 0;
    1206
    1207        for (int i = 0; i <= lastShadow; i++) {
    1208            final byte ll_i = unseqToSeq[block[fmap[i]] & 0xff];
    1209            byte tmp = yy[0];
    1210            int j = 0;
    1211
    1212            while (ll_i != tmp) {
    1213                j++;
    1214                final byte tmp2 = tmp;
    1215                tmp = yy[j];
    1216                yy[j] = tmp2;
    1217            }
    1218            yy[0] = tmp;
    1219
    1220            if (j == 0) {
    1221                zPend++;
    1222            } else {
    1223                if (zPend > 0) {
    1224                    zPend--;
    1225                    while (true) {
    1226                        if ((zPend & 1) == 0) {
    1227                            sfmap[wr] = RUNA;
    1228                            wr++;
    1229                            mtfFreq[RUNA]++;
    1230                        } else {
    1231                            sfmap[wr] = RUNB;
    1232                            wr++;
    1233                            mtfFreq[RUNB]++;
    1234                        }
    1235
    1236                        if (zPend >= 2) {
    1237                            zPend = (zPend - 2) >> 1;
    1238                        } else {
    1239                            break;
    1240                        }
    1241                    }
    1242                    zPend = 0;
    1243                }
    1244                sfmap[wr] = (char) (j + 1);
    1245                wr++;
    1246                mtfFreq[j + 1]++;
    1247            }
    1248        }
    1249
    1250        if (zPend > 0) {
    1251            zPend--;
    1252            while (true) {
    1253                if ((zPend & 1) == 0) {
    1254                    sfmap[wr] = RUNA;
    1255                    wr++;
    1256                    mtfFreq[RUNA]++;
    1257                } else {
    1258                    sfmap[wr] = RUNB;
    1259                    wr++;
    1260                    mtfFreq[RUNB]++;
    1261                }
    1262
    1263                if (zPend >= 2) {
    1264                    zPend = (zPend - 2) >> 1;
    1265                } else {
    1266                    break;
    1267                }
    1268            }
    1269        }
    1270
    1271        sfmap[wr] = (char) eob;
    1272        mtfFreq[eob]++;
    1273        this.nMTF = wr + 1;
    1274    }
    1275
    1276    static final class Data {
    1277
    1278        // with blockSize 900k
    1279        /* maps unsigned byte => "does it occur in block" */
    1280        final boolean[] inUse = new boolean[256]; // 256 byte
    1281        final byte[] unseqToSeq = new byte[256]; // 256 byte
    1282        final int[] mtfFreq = new int[MAX_ALPHA_SIZE]; // 1032 byte
    1283        final byte[] selector = new byte[MAX_SELECTORS]; // 18002 byte
    1284        final byte[] selectorMtf = new byte[MAX_SELECTORS]; // 18002 byte
    1285
    1286        final byte[] generateMTFValues_yy = new byte[256]; // 256 byte
    1287        final byte[][] sendMTFValues_len = new byte[N_GROUPS][MAX_ALPHA_SIZE]; // 1548
    1288        // byte
    1289        final int[][] sendMTFValues_rfreq = new int[N_GROUPS][MAX_ALPHA_SIZE]; // 6192
    1290        // byte
    1291        final int[] sendMTFValues_fave = new int[N_GROUPS]; // 24 byte
    1292        final short[] sendMTFValues_cost = new short[N_GROUPS]; // 12 byte
    1293        final int[][] sendMTFValues_code = new int[N_GROUPS][MAX_ALPHA_SIZE]; // 6192
    1294        // byte
    1295        final byte[] sendMTFValues2_pos = new byte[N_GROUPS]; // 6 byte
    1296        final boolean[] sentMTFValues4_inUse16 = new boolean[16]; // 16 byte
    1297
    1298        final int[] heap = new int[MAX_ALPHA_SIZE + 2]; // 1040 byte
    1299        final int[] weight = new int[MAX_ALPHA_SIZE * 2]; // 2064 byte
    1300        final int[] parent = new int[MAX_ALPHA_SIZE * 2]; // 2064 byte
    1301
    1302        // ------------
    1303        // 333408 byte
    1304
    1305        /* holds the RLEd block of original data starting at index 1.
    1306         * After sorting the last byte added to the buffer is at index
    1307         * 0. */
    1308        final byte[] block; // 900021 byte
    1309        /* maps index in Burrows-Wheeler transformed block => index of
    1310         * byte in original block */
    1311        final int[] fmap; // 3600000 byte
    1312        final char[] sfmap; // 3600000 byte
    1313        // ------------
    1314        // 8433529 byte
    1315        // ============
    1316
    1317        /**
    1318         * Index of original line in Burrows-Wheeler table.
    1319         *
    1320         * <p>This is the index in fmap that points to the last byte
    1321         * of the original data.</p>
    1322         */
    1323        int origPtr;
    1324
    1325        Data(final int blockSize100k) {
    1326            final int n = blockSize100k * BZip2Constants.BASEBLOCKSIZE;
    1327            this.block = new byte[(n + 1 + NUM_OVERSHOOT_BYTES)];
    1328            this.fmap = new int[n];
    1329            this.sfmap = new char[2 * n];
    1330        }
    1331
    1332    }
    1333
    1334}