kusamoji/src/dict/InvokeDefinitionMap.js

Japanese morphological analyzer for Node.js — Viterbi tokenizer with mmap dict loading and pluggable POS-source strategy

"use strict";

let ByteBuffer = require("../util/ByteBuffer");
let CharacterClass = require("./CharacterClass");

/**
 * InvokeDefinitionMap represents invoke definition a part of char.def
 * @constructor
 */
function InvokeDefinitionMap() {
    this.map = [];
    this.lookup_table = {};  // Just for building dictionary
}

/**
 * Load InvokeDefinitionMap from buffer
 * @param {Uint8Array} invoke_def_buffer
 * @returns {InvokeDefinitionMap}
 */
InvokeDefinitionMap.load = function (invoke_def_buffer) {
    let invoke_def = new InvokeDefinitionMap();
    let character_category_definition = [];

    let buffer = new ByteBuffer(invoke_def_buffer);
    while (buffer.position + 1 < buffer.size()) {
        let class_id = character_category_definition.length;
        let is_always_invoke = buffer.get();
        let is_grouping = buffer.get();
        let max_length = buffer.getInt();
        let class_name = buffer.getString();
        character_category_definition.push(new CharacterClass(class_id, class_name, is_always_invoke, is_grouping, max_length));
    }

    invoke_def.init(character_category_definition);

    return invoke_def;
};

/**
 * Initializing method
 * @param {Array.<CharacterClass>} character_category_definition Array of CharacterClass
 */
InvokeDefinitionMap.prototype.init = function (character_category_definition) {
    if (character_category_definition == null) {
        return;
    }
    for (let i = 0; i < character_category_definition.length; i++) {
        let character_class = character_category_definition[i];
        this.map[i] = character_class;
        this.lookup_table[character_class.class_name] = i;
    }
};

/**
 * Get class information by class ID
 * @param {number} class_id
 * @returns {CharacterClass}
 */
InvokeDefinitionMap.prototype.getCharacterClass = function (class_id) {
    return this.map[class_id];
};

/**
 * For building character definition dictionary
 * @param {string} class_name character
 * @returns {number} class_id
 */
InvokeDefinitionMap.prototype.lookup = function (class_name) {
    let class_id = this.lookup_table[class_name];
    if (class_id == null) {
        return null;
    }
    return class_id;
};

/**
 * Transform from map to binary buffer
 * @returns {Uint8Array}
 */
InvokeDefinitionMap.prototype.toBuffer = function () {
    let buffer = new ByteBuffer();
    for (let i = 0; i < this.map.length; i++) {
        let char_class = this.map[i];
        buffer.put(char_class.is_always_invoke);
        buffer.put(char_class.is_grouping);
        buffer.putInt(char_class.max_length);
        buffer.putString(char_class.class_name);
    }
    buffer.shrink();
    return buffer.buffer;
};

module.exports = InvokeDefinitionMap;