image-in-browser/lib/formats/webp/webp-huffman-tree.d.ts

Package for encoding / decoding images, transforming images, applying filters, drawing primitives on images on the client side (no need for server Node.js)

/** @format */
import { VP8LBitReader } from './vp8l-bit-reader.js';
/**
 * Class representing a Huffman Tree.
 */
export declare class HuffmanTree {
    /**
     * Fast lookup for short bit lengths.
     * @private
     */
    private readonly _lutBits;
    /**
     * Fast lookup for symbols.
     * @private
     */
    private readonly _lutSymbol;
    /**
     * Fast lookup for jump values.
     * @private
     */
    private readonly _lutJump;
    /**
     * All the nodes, starting at root, stored as a single int array, where
     * each node occupies two ints as [symbol, children].
     * @private
     */
    private _tree;
    /**
     * Maximum number of nodes.
     * @private
     */
    private _maxNodes;
    /**
     * Number of currently occupied nodes.
     * @private
     */
    private _numNodes;
    /**
     * Gets the number of currently occupied nodes.
     * @returns {number} The number of nodes.
     */
    get numNodes(): number;
    /**
     * Checks if the tree is full.
     * @returns {boolean} True if the tree is full, false otherwise.
     */
    get isFull(): boolean;
    /**
     * Creates an instance of HuffmanTree.
     * @param {number} [numLeaves=0] - The number of leaves.
     */
    constructor(numLeaves?: number);
    /**
     * Adds a symbol to the Huffman tree.
     * @private
     * @param {number} symbol - The symbol to add.
     * @param {number} code - The code for the symbol.
     * @param {number} codeLength - The length of the code.
     * @returns {boolean} True if the symbol was added successfully, false otherwise.
     */
    private addSymbol;
    /**
     * Reverses the bits of a short integer.
     * @private
     * @param {number} bits - The bits to reverse.
     * @param {number} numBits - The number of bits.
     * @returns {number} The reversed bits.
     */
    private reverseBitsShort;
    /**
     * Gets the next node in the tree.
     * @private
     * @param {number} node - The current node.
     * @param {number} rightChild - The right child.
     * @returns {number} The next node.
     */
    private nextNode;
    /**
     * Gets the symbol of a node.
     * @private
     * @param {number} node - The node.
     * @returns {number} The symbol.
     */
    private nodeSymbol;
    /**
     * Sets the symbol of a node.
     * @private
     * @param {number} node - The node.
     * @param {number} symbol - The symbol.
     */
    private nodeSetSymbol;
    /**
     * Gets the children of a node.
     * @private
     * @param {number} node - The node.
     * @returns {number} The children.
     */
    private nodeChildren;
    /**
     * Sets the children of a node.
     * @private
     * @param {number} node - The node.
     * @param {number} children - The children.
     */
    private nodeSetChildren;
    /**
     * Checks if a node is not a leaf.
     * @private
     * @param {number} node - The node.
     * @returns {boolean} True if the node is not a leaf, false otherwise.
     */
    private nodeIsNotLeaf;
    /**
     * Checks if a node is empty.
     * @private
     * @param {number} node - The node.
     * @returns {boolean} True if the node is empty, false otherwise.
     */
    private nodeIsEmpty;
    /**
     * Assigns children to a node.
     * @private
     * @param {number} node - The node.
     */
    private assignChildren;
    /**
     * Converts Huffman code lengths to codes.
     * @private
     * @param {Int32Array} codeLengths - The code lengths.
     * @param {number} codeLengthsSize - The size of the code lengths.
     * @param {Int32Array} huffCodes - The Huffman codes.
     * @returns {boolean} True if the conversion was successful, false otherwise.
     */
    private huffmanCodeLengthsToCodes;
    /**
     * Initializes the Huffman tree.
     * @private
     * @param {number} numLeaves - The number of leaves.
     * @returns {boolean} True if the initialization was successful, false otherwise.
     */
    private init;
    /**
     * Builds the Huffman tree implicitly.
     * @param {Int32Array} codeLengths - The code lengths.
     * @param {number} codeLengthsSize - The size of the code lengths.
     * @returns {boolean} True if the tree was built successfully, false otherwise.
     */
    buildImplicit(codeLengths: Int32Array, codeLengthsSize: number): boolean;
    /**
     * Builds the Huffman tree explicitly.
     * @param {number[]} codeLengths - The code lengths.
     * @param {number[]} codes - The codes.
     * @param {number[]} symbols - The symbols.
     * @param {number} maxSymbol - The maximum symbol.
     * @param {number} numSymbols - The number of symbols.
     * @returns {boolean} True if the tree was built successfully, false otherwise.
     */
    buildExplicit(codeLengths: number[], codes: number[], symbols: number[], maxSymbol: number, numSymbols: number): boolean;
    /**
     * Decodes the next Huffman code from bit-stream.
     * @param {VP8LBitReader} br - The bit reader.
     * @returns {number} The decoded symbol.
     */
    readSymbol(br: VP8LBitReader): number;
    /**
     * Number of bits for Huffman lookup table.
     * @private
     * @static
     */
    private static readonly huffmanLutBits;
    /**
     * Size of Huffman lookup table.
     * @private
     * @static
     */
    private static readonly huffmanLut;
    /**
     * Pre-reversed 4-bit values.
     * @private
     * @static
     */
    private static readonly reversedBits;
}