Class Decode

java/org/brotli/dec/Decode.java:38–1574

API for Brotli decompression.

 * API for Brotli decompression.
 */
final class Decode {

  static final int MIN_LARGE_WINDOW_BITS = 10;
  /* Maximum was chosen to be 30 to allow efficient decoder implementation.
   * Format allows bigger window, but Java does not support 2G+ arrays. */
  static final int MAX_LARGE_WINDOW_BITS = 30;

  //----------------------------------------------------------------------------
  // RunningState
  //----------------------------------------------------------------------------
  // NB: negative values are used for errors.
  private static final int UNINITIALIZED = 0;
  private static final int INITIALIZED = 1;
  private static final int BLOCK_START = 2;
  private static final int COMPRESSED_BLOCK_START = 3;
  private static final int MAIN_LOOP = 4;
  private static final int READ_METADATA = 5;
  private static final int COPY_UNCOMPRESSED = 6;
  private static final int INSERT_LOOP = 7;
  private static final int COPY_LOOP = 8;
  private static final int USE_DICTIONARY = 9;
  private static final int FINISHED = 10;
  private static final int CLOSED = 11;
  private static final int INIT_WRITE = 12;
  private static final int WRITE = 13;
  private static final int COPY_FROM_COMPOUND_DICTIONARY = 14;

  private static final int DEFAULT_CODE_LENGTH = 8;
  private static final int CODE_LENGTH_REPEAT_CODE = 16;
  private static final int NUM_LITERAL_CODES = 256;
  private static final int NUM_COMMAND_CODES = 704;
  private static final int NUM_BLOCK_LENGTH_CODES = 26;
  private static final int LITERAL_CONTEXT_BITS = 6;
  private static final int DISTANCE_CONTEXT_BITS = 2;

  private static final int CD_BLOCK_MAP_BITS = 8;
  private static final int HUFFMAN_TABLE_BITS = 8;
  private static final int HUFFMAN_TABLE_MASK = 0xFF;

  /**
   * Maximum possible Huffman table size for an alphabet size of (index * 32),
   * max code length 15 and root table bits 8.
   * The biggest alphabet is "command" - 704 symbols. Though "distance" alphabet could theoretically
   * outreach that limit (for 62 extra bit distances), practically it is limited by
   * MAX_ALLOWED_DISTANCE and never gets bigger than 544 symbols.
   */
  static final int[] MAX_HUFFMAN_TABLE_SIZE = {
      256, 402, 436, 468, 500, 534, 566, 598, 630, 662, 694, 726, 758, 790, 822,
      854, 886, 920, 952, 984, 1016, 1048, 1080
  };

  private static final int HUFFMAN_TABLE_SIZE_26 = 396;
  private static final int HUFFMAN_TABLE_SIZE_258 = 632;

  private static final int CODE_LENGTH_CODES = 18;
  private static final int[] CODE_LENGTH_CODE_ORDER = {
      1, 2, 3, 4, 0, 5, 17, 6, 16, 7, 8, 9, 10, 11, 12, 13, 14, 15,
  };