glink-website/node_modules/cassandra-driver/lib/geometry/polygon.js

/*
 * Copyright DataStax, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
'use strict';
const util = require('util');
const utils = require('../utils');
const Geometry = require('./geometry');
const Point = require('./point');
const LineString = require('./line-string');

/**
 * Creates a new {@link Polygon} instance.
 * @classdesc
 * Represents is a plane geometry figure that is bounded by a finite chain of straight line segments closing in a loop
 * to form a closed chain or circuit.
 * @param {...Array.<Point>}[ringPoints] A sequence of Array of [Point]{@link module:geometry~Point} items as arguments
 * representing the rings of the polygon.
 * @example
 * new Polygon([ new Point(30, 10), new Point(40, 40), new Point(10, 20), new Point(30, 10) ]);
 * @example
 * //polygon with a hole
 * new Polygon(
 *  [ new Point(30, 10), new Point(40, 40), new Point(10, 20), new Point(30, 10) ],
 *  [ new Point(25, 20), new Point(30, 30), new Point(20, 20), new Point(25, 20) ]
 * );
 * @alias module:geometry~Polygon
 * @constructor
 */
function Polygon(ringPoints) {
  const rings = Array.prototype.slice.call(arguments);
  /**
   * Returns a frozen Array of array of points that represent the different rings in the polygon.
   * @type {Array}
   */
  this.rings = Object.freeze(rings);
}

//noinspection JSCheckFunctionSignatures
util.inherits(Polygon, Geometry);

/**
 * Creates a {@link Polygon} instance from
 * a <a href="https://en.wikipedia.org/wiki/Well-known_text">Well-known Text (WKT)</a>
 * representation of a polygon.
 * @param {Buffer} buffer
 * @returns {Polygon}
 */
Polygon.fromBuffer = function (buffer) {
  if (!buffer || buffer.length < 9) {
    throw new TypeError('A Polygon buffer should contain at least 9 bytes');
  }
  const endianness = Geometry.getEndianness(buffer.readInt8(0, true));
  let offset = 1;
  if (Geometry.readInt32(buffer, endianness, offset) !== Geometry.types.Polygon) {
    throw new TypeError('Binary representation was not a Polygon');
  }
  offset += 4;
  const ringsLength = Geometry.readInt32(buffer, endianness, offset);
  offset += 4;
  const ringsArray = new Array(ringsLength);
  for (let ringIndex = 0; ringIndex < ringsLength; ringIndex++) {
    const pointsLength = Geometry.readInt32(buffer, endianness, offset);
    offset += 4;
    if (buffer.length < offset + pointsLength * 16) {
      throw new TypeError(util.format('Length of the buffer does not match'));
    }
    const ring = new Array(pointsLength);
    for (let i = 0; i < pointsLength; i++) {
      ring[i] = new Point(
        Geometry.readDouble(buffer, endianness, offset),
        Geometry.readDouble(buffer, endianness, offset + 8));
      offset += 16;
    }
    ringsArray[ringIndex] = ring;
  }
  //Invoke the constructor with each ring as a parameter
  //ringsArray.unshift(null);
  //return new (Function.prototype.bind.apply(Polygon, ringsArray));
  return construct(ringsArray);
};

/**
 * Creates a {@link Polygon} instance from
 * a <a href="https://en.wikipedia.org/wiki/Well-known_text">Well-known Text (WKT)</a>
 * representation of a shape.
 * @param {String} textValue
 * @returns {Polygon}
 */
Polygon.fromString = function (textValue) {
  const wktRegex = /^POLYGON ?\((\(.*\))\)$/g;
  const matches = wktRegex.exec(textValue);
  function validateWkt(condition) {
    if (condition) {
      throw new TypeError('Invalid WKT: ' + textValue);
    }
  }
  validateWkt(!matches || matches.length !== 2);

  const ringsText = matches[1];
  const ringsArray = [];
  let ringStart = null;
  for (let i = 0; i < ringsText.length; i++) {
    const c = ringsText[i];
    if (c === '(') {
      validateWkt(ringStart !== null);
      ringStart = i+1;
      continue;
    }
    if (c === ')') {
      validateWkt(ringStart === null);
      ringsArray.push(ringsText.substring(ringStart, i));
      ringStart = null;
      continue;
    }
    validateWkt(ringStart === null && c !== ' ' && c !== ',');
  }
  return construct(ringsArray.map(LineString.parseSegments));
};

/**
 * Creates a new instance of Polygon with each array item as a parameter
 * @private
 * @param {Array<Array<Point>>} argsArray
 * @returns {Polygon}
 */
function construct(argsArray) {
  function F() {
    return Polygon.apply(this, argsArray);
  }
  F.prototype = Polygon.prototype;
  return new F();
}

/**
 * Returns a <a href="https://en.wikipedia.org/wiki/Well-known_text#Well-known_binary">Well-known Binary</a> (WKB)
 * representation of this instance.
 * @returns {Buffer}
 */
Polygon.prototype.toBuffer = function () {
  let totalRingsLength = 0;
  this.rings.forEach(function (ring) {
    totalRingsLength += 4 + ring.length * 16;
  }, this);
  const buffer = utils.allocBufferUnsafe(9 + totalRingsLength);
  this.writeEndianness(buffer, 0);
  let offset = 1;
  this.writeInt32(Geometry.types.Polygon, buffer, offset);
  offset += 4;
  this.writeInt32(this.rings.length, buffer, offset);
  offset += 4;
  this.rings.forEach(function (ring) {
    this.writeInt32(ring.length, buffer, offset);
    offset += 4;
    ring.forEach(function (p) {
      this.writeDouble(p.x, buffer, offset);
      this.writeDouble(p.y, buffer, offset + 8);
      offset += 16;
    }, this);
  }, this);
  return buffer;
};

/**
 * Returns true if the values of the polygons are the same, otherwise it returns false.
 * @param {Polygon} other
 * @returns {Boolean}
 */
Polygon.prototype.equals = function (other) {
  if (!(other instanceof Polygon)) {
    return false;
  }
  if (this.rings.length !== other.rings.length) {
    return false;
  }
  for (let i = 0; i < this.rings.length; i++) {
    const r1 = this.rings[i];
    const r2 = other.rings[i];
    if (r1.length !== r2.length) {
      return false;
    }
    for (let j = 0; j < r1.length; j++) {
      if (!r1[i].equals(r2[i])) {
        return false;
      }
    }
  }
  return true;
};

Polygon.prototype.useBESerialization = function () {
  return false;
};

/**
 * Returns Well-known text (WKT) representation of the geometry object.
 * @returns {String}
 */
Polygon.prototype.toString = function () {
  if (this.rings.length === 0) {
    return 'POLYGON EMPTY';
  }
  let ringStrings = '';
  this.rings.forEach(function (r, i) {
    if (i > 0) {
      ringStrings += ', ';
    }
    ringStrings += '(' +
      r.map(function (p) {
        return p.x + ' ' + p.y;
      }).join(', ')
      + ')';
  });
  return 'POLYGON (' + ringStrings + ')';
};

/**
 * Returns a JSON representation of this geo-spatial type.
 */
Polygon.prototype.toJSON = function () {
  return { type: 'Polygon', coordinates: this.rings.map(function (r) {
    return r.map(function (p) {
      return [ p.x, p.y ];
    });
  })};
};

module.exports = Polygon;