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

Random numbers for decompress Bzip2 blocks.
/**
 * Random numbers for decompress Bzip2 blocks.
 */
final class Bzip2Rand {
    
The Bzip2 specification originally included the optional addition of a slight pseudo-random
perturbation to the input data, in order to work around the block sorting algorithm's non-
optimal performance on some types of input. The current mainline bzip2 does not require this
and will not create randomised blocks, but compatibility is still required for old data (and
third party compressors that haven't caught up). When decompressing a randomised block, for
each value N in this array, a 1 will be XOR'd onto the output of the Burrows-Wheeler
transform stage after N bytes, then the next N taken from the following entry.
/**
     * The Bzip2 specification originally included the optional addition of a slight pseudo-random
     * perturbation to the input data, in order to work around the block sorting algorithm's non-
     * optimal performance on some types of input. The current mainline bzip2 does not require this
     * and will not create randomised blocks, but compatibility is still required for old data (and
     * third party compressors that haven't caught up). When decompressing a randomised block, for
     * each value N in this array, a 1 will be XOR'd onto the output of the Burrows-Wheeler
     * transform stage after N bytes, then the next N taken from the following entry.
     */
    private static final int[] RNUMS = {
            619, 720, 127, 481, 931, 816, 813, 233, 566, 247, 985, 724, 205, 454, 863, 491,
            741, 242, 949, 214, 733, 859, 335, 708, 621, 574,  73, 654, 730, 472, 419, 436,
            278, 496, 867, 210, 399, 680, 480,  51, 878, 465, 811, 169, 869, 675, 611, 697,
            867, 561, 862, 687, 507, 283, 482, 129, 807, 591, 733, 623, 150, 238,  59, 379,
            684, 877, 625, 169, 643, 105, 170, 607, 520, 932, 727, 476, 693, 425, 174, 647,
             73, 122, 335, 530, 442, 853, 695, 249, 445, 515, 909, 545, 703, 919, 874, 474,
            882, 500, 594, 612, 641, 801, 220, 162, 819, 984, 589, 513, 495, 799, 161, 604,
            958, 533, 221, 400, 386, 867, 600, 782, 382, 596, 414, 171, 516, 375, 682, 485,
            911, 276,  98, 553, 163, 354, 666, 933, 424, 341, 533, 870, 227, 730, 475, 186,
            263, 647, 537, 686, 600, 224, 469,  68, 770, 919, 190, 373, 294, 822, 808, 206,
            184, 943, 795, 384, 383, 461, 404, 758, 839, 887, 715,  67, 618, 276, 204, 918,
            873, 777, 604, 560, 951, 160, 578, 722,  79, 804,  96, 409, 713, 940, 652, 934,
            970, 447, 318, 353, 859, 672, 112, 785, 645, 863, 803, 350, 139,  93, 354,  99,
            820, 908, 609, 772, 154, 274, 580, 184,  79, 626, 630, 742, 653, 282, 762, 623,
            680,  81, 927, 626, 789, 125, 411, 521, 938, 300, 821,  78, 343, 175, 128, 250,
            170, 774, 972, 275, 999, 639, 495,  78, 352, 126, 857, 956, 358, 619, 580, 124,
            737, 594, 701, 612, 669, 112, 134, 694, 363, 992, 809, 743, 168, 974, 944, 375,
            748,  52, 600, 747, 642, 182, 862,  81, 344, 805, 988, 739, 511, 655, 814, 334,
            249, 515, 897, 955, 664, 981, 649, 113, 974, 459, 893, 228, 433, 837, 553, 268,
            926, 240, 102, 654, 459,  51, 686, 754, 806, 760, 493, 403, 415, 394, 687, 700,
            946, 670, 656, 610, 738, 392, 760, 799, 887, 653, 978, 321, 576, 617, 626, 502,
            894, 679, 243, 440, 680, 879, 194, 572, 640, 724, 926,  56, 204, 700, 707, 151,
            457, 449, 797, 195, 791, 558, 945, 679, 297,  59,  87, 824, 713, 663, 412, 693,
            342, 606, 134, 108, 571, 364, 631, 212, 174, 643, 304, 329, 343,  97, 430, 751,
            497, 314, 983, 374, 822, 928, 140, 206,  73, 263, 980, 736, 876, 478, 430, 305,
            170, 514, 364, 692, 829,  82, 855, 953, 676, 246, 369, 970, 294, 750, 807, 827,
            150, 790, 288, 923, 804, 378, 215, 828, 592, 281, 565, 555, 710,  82, 896, 831,
            547, 261, 524, 462, 293, 465, 502,  56, 661, 821, 976, 991, 658, 869, 905, 758,
            745, 193, 768, 550, 608, 933, 378, 286, 215, 979, 792, 961,  61, 688, 793, 644,
            986, 403, 106, 366, 905, 644, 372, 567, 466, 434, 645, 210, 389, 550, 919, 135,
            780, 773, 635, 389, 707, 100, 626, 958, 165, 504, 920, 176, 193, 713, 857, 265,
            203,  50, 668, 108, 645, 990, 626, 197, 510, 357, 358, 850, 858, 364, 936, 638
    };

    
Return the random number at a specific index.
Params:
i – the index
Returns:
the random number/**
     * Return the random number at a specific index.
     *
     * @param i the index
     * @return the random number
     */
    static int rNums(int i) {
        return RNUMS[i];
    }

    private Bzip2Rand() { }
}