heli-agri/lib/structs/RBush.js

HeliAgri is a high-performance, feature-packed library for creating interactive maps on the web. It can display map tiles, vector data and markers loaded from any source on any web page. OpenLayers has been developed to further the use of geographic infor

/**
 * @module ol/structs/RBush
 */
import RBush_ from 'rbush';
import {createOrUpdate, equals} from '../extent.js';
import {getUid} from '../util.js';
import {isEmpty} from '../obj.js';

/**
 * @typedef {Object} Entry
 * @property {number} minX MinX.
 * @property {number} minY MinY.
 * @property {number} maxX MaxX.
 * @property {number} maxY MaxY.
 * @property {Object} [value] Value.
 */

/**
 * @classdesc
 * Wrapper around the RBush by Vladimir Agafonkin.
 * See https://github.com/mourner/rbush.
 *
 * @template T
 */
class RBush {
  /**
   * @param {number} [maxEntries] Max entries.
   */
  constructor(maxEntries) {
    /**
     * @private
     */
    this.rbush_ = new RBush_(maxEntries);

    /**
     * A mapping between the objects added to this rbush wrapper
     * and the objects that are actually added to the internal rbush.
     * @private
     * @type {Object<string, Entry>}
     */
    this.items_ = {};
  }

  /**
   * Insert a value into the RBush.
   * @param {import("../extent.js").Extent} extent Extent.
   * @param {T} value Value.
   */
  insert(extent, value) {
    /** @type {Entry} */
    const item = {
      minX: extent[0],
      minY: extent[1],
      maxX: extent[2],
      maxY: extent[3],
      value: value,
    };

    this.rbush_.insert(item);
    this.items_[getUid(value)] = item;
  }

  /**
   * Bulk-insert values into the RBush.
   * @param {Array<import("../extent.js").Extent>} extents Extents.
   * @param {Array<T>} values Values.
   */
  load(extents, values) {
    const items = new Array(values.length);
    for (let i = 0, l = values.length; i < l; i++) {
      const extent = extents[i];
      const value = values[i];

      /** @type {Entry} */
      const item = {
        minX: extent[0],
        minY: extent[1],
        maxX: extent[2],
        maxY: extent[3],
        value: value,
      };
      items[i] = item;
      this.items_[getUid(value)] = item;
    }
    this.rbush_.load(items);
  }

  /**
   * Remove a value from the RBush.
   * @param {T} value Value.
   * @return {boolean} Removed.
   */
  remove(value) {
    const uid = getUid(value);

    // get the object in which the value was wrapped when adding to the
    // internal rbush. then use that object to do the removal.
    const item = this.items_[uid];
    delete this.items_[uid];
    return this.rbush_.remove(item) !== null;
  }

  /**
   * Update the extent of a value in the RBush.
   * @param {import("../extent.js").Extent} extent Extent.
   * @param {T} value Value.
   */
  update(extent, value) {
    const item = this.items_[getUid(value)];
    const bbox = [item.minX, item.minY, item.maxX, item.maxY];
    if (!equals(bbox, extent)) {
      this.remove(value);
      this.insert(extent, value);
    }
  }

  /**
   * Return all values in the RBush.
   * @return {Array<T>} All.
   */
  getAll() {
    const items = this.rbush_.all();
    return items.map(function (item) {
      return item.value;
    });
  }

  /**
   * Return all values in the given extent.
   * @param {import("../extent.js").Extent} extent Extent.
   * @return {Array<T>} All in extent.
   */
  getInExtent(extent) {
    /** @type {Entry} */
    const bbox = {
      minX: extent[0],
      minY: extent[1],
      maxX: extent[2],
      maxY: extent[3],
    };
    const items = this.rbush_.search(bbox);
    return items.map(function (item) {
      return item.value;
    });
  }

  /**
   * Calls a callback function with each value in the tree.
   * If the callback returns a truthy value, this value is returned without
   * checking the rest of the tree.
   * @param {function(T): *} callback Callback.
   * @return {*} Callback return value.
   */
  forEach(callback) {
    return this.forEach_(this.getAll(), callback);
  }

  /**
   * Calls a callback function with each value in the provided extent.
   * @param {import("../extent.js").Extent} extent Extent.
   * @param {function(T): *} callback Callback.
   * @return {*} Callback return value.
   */
  forEachInExtent(extent, callback) {
    return this.forEach_(this.getInExtent(extent), callback);
  }

  /**
   * @param {Array<T>} values Values.
   * @param {function(T): *} callback Callback.
   * @private
   * @return {*} Callback return value.
   */
  forEach_(values, callback) {
    let result;
    for (let i = 0, l = values.length; i < l; i++) {
      result = callback(values[i]);
      if (result) {
        return result;
      }
    }
    return result;
  }

  /**
   * @return {boolean} Is empty.
   */
  isEmpty() {
    return isEmpty(this.items_);
  }

  /**
   * Remove all values from the RBush.
   */
  clear() {
    this.rbush_.clear();
    this.items_ = {};
  }

  /**
   * @param {import("../extent.js").Extent} [extent] Extent.
   * @return {import("../extent.js").Extent} Extent.
   */
  getExtent(extent) {
    const data = this.rbush_.toJSON();
    return createOrUpdate(data.minX, data.minY, data.maxX, data.maxY, extent);
  }

  /**
   * @param {RBush} rbush R-Tree.
   */
  concat(rbush) {
    this.rbush_.load(rbush.rbush_.all());
    for (const i in rbush.items_) {
      this.items_[i] = rbush.items_[i];
    }
  }
}

export default RBush;