Class Huffman

java.lang.Object
org.brotli.dec.Huffman
final class Huffman extends Object
Utilities for building Huffman decoding tables.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private static final int
    MAX_LENGTH
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    Huffman()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    (package private) static int
    buildHuffmanTable(int[] tableGroup, int tableIdx, int rootBits, int[] codeLengths, int codeLengthsSize)
    Builds Huffman lookup table assuming code lengths are in symbol order.
    private static int
    getNextKey(int key, int len)
    Returns reverse(reverse(key, len) + 1, len).
    private static int
    nextTableBitSize(int[] count, int len, int rootBits)
     
    private static void
    replicateValue(int[] table, int offset, int step, int end, int item)
    Stores item in table[0], table[step], table[2 * step] .., table[end].

    Methods inherited from class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

  • Constructor Details

    • Huffman

      Huffman()

  • Method Details

    • getNextKey

      private static int getNextKey(int key, int len)
      Returns reverse(reverse(key, len) + 1, len).

      reverse(key, len) is the bit-wise reversal of the len least significant bits of key.

    • replicateValue

      private static void replicateValue(int[] table, int offset, int step, int end, int item)
      Stores item in table[0], table[step], table[2 * step] .., table[end].

      Assumes that end is an integer multiple of step.

    • nextTableBitSize

      private static int nextTableBitSize(int[] count, int len, int rootBits)
      Parameters:
      count - histogram of bit lengths for the remaining symbols,
      len - code length of the next processed symbol.
      Returns:
      table width of the next 2nd level table.

    • buildHuffmanTable

      static int buildHuffmanTable(int[] tableGroup, int tableIdx, int rootBits, int[] codeLengths, int codeLengthsSize)
      Builds Huffman lookup table assuming code lengths are in symbol order.
      Returns:
      number of slots used by resulting Huffman table