Package it.unimi.dsi.compression

Class TreeDecoder

java.lang.Object
it.unimi.dsi.compression.TreeDecoder
All Implemented Interfaces:
Decoder, Serializable
public final class TreeDecoder extends Object implements Decoder, Serializable
A decoder that follows 0/1 labelled paths in a tree.

Additional, the buildCodes() method returns a vector of codewords corresponding to the paths of an instance of this class. Conversely, the codeword-based constructor builds a tree out of the codewords generated by root-to-leaf paths.

See Also:

  • Constructor Details

    • TreeDecoder

      public TreeDecoder(TreeDecoder.Node root, int n)
      Creates a new codeword-based decoder using the given tree. It is responsibility of the caller that the tree is well-formed, that is, that all internal nodes are instances of TreeDecoder.Node and all leaf nodes are instances of TreeDecoder.LeafNode.
      Parameters:
      root - the root of a decoding tree.
      n - the number of leaves (symbols).

    • TreeDecoder

      public TreeDecoder(BitVector[] lexSortedCodeWord, int[] symbol)
      Creates a new codeword-based decoder starting from a set of complete, lexicographically ordered codewords. It is responsibility of the caller that the tree is well-formed, that is, that the provided codewords are exactly the root-to-leaf paths of such a tree.
      Parameters:
      lexSortedCodeWord - a vector of lexically sorted codeWords.
      symbol - a mapping from codewords to symbols.

  • Method Details

    • decode

      public int decode(BooleanIterator iterator)
      Description copied from interface: Decoder
      Decodes the next symbol from the given boolean iterator.

      Note that InputBitStream implements BooleanIterator.

      Specified by:
      decode in interface Decoder
      Parameters:
      iterator - a boolean iterator.
      Returns:
      the next symbol decoded from the bits emitted by i

    • decode

      public int decode(InputBitStream ibs) throws IOException
      Description copied from interface: Decoder
      Decodes the next symbol from the given input bit stream.

      Note that InputBitStream implements BooleanIterator.

      Specified by:
      decode in interface Decoder
      Parameters:
      ibs - an input bit stream.
      Returns:
      the next symbol decoded from ibs.
      Throws:
      IOException

    • buildCodes

      public BitVector[] buildCodes()
      Generate the codewords corresponding to this tree decoder.
      Returns:
      a vector of codewords for this decoder.

    • succinctRepresentation

      public LongArrayBitVector succinctRepresentation()