time-to-botec

main.js (9864B)

---

 /**
 * @license Apache-2.0
 *
 * Copyright (c) 2018 The Stdlib Authors.
 *
 * 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.
 */
 
 /* eslint-disable no-restricted-syntax, no-invalid-this */
 
 'use strict';
 
 // MODULES //
 
 var isCollection = require( '@stdlib/assert/is-collection' );
 var isPositiveInteger = require( '@stdlib/assert/is-positive-integer' ).isPrimitive;
 var isNonNegativeInteger = require( '@stdlib/assert/is-nonnegative-integer' ).isPrimitive;
 var setReadOnly = require( './../../define-nonenumerable-read-only-property' );
 var setReadOnlyAccessor = require( './../../define-nonenumerable-read-only-accessor' );
 var iteratorSymbol = require( '@stdlib/symbol/iterator' );
 var MAX_ITERATIONS = require( '@stdlib/constants/float64/max' );
 
 
 // MAIN //
 
 /**
 * Circular buffer constructor.
 *
 * @constructor
 * @param {(PositiveInteger|Collection)} buffer - buffer size or an array-like object to use as the underlying buffer
 * @throws {TypeError} must provide either a valid buffer size or an array-like object
 * @returns {CircularBuffer} circular buffer instance
 *
 * @example
 * var b = new CircularBuffer( 3 );
 *
 * // Fill the buffer...
 * var v = b.push( 'foo' );
 * // returns undefined
 *
 * v = b.push( 'bar' );
 * // returns undefined
 *
 * v = b.push( 'beep' );
 * // returns undefined
 *
 * // Add another value to the buffer and return the removed element:
 * v = b.push( 'boop' );
 * // returns 'foo'
 */
 function CircularBuffer( buffer ) {
 	var i;
 	if ( !(this instanceof CircularBuffer) ) {
 		return new CircularBuffer( buffer );
 	}
 	if ( isPositiveInteger( buffer ) ) {
 		this._buffer = [];
 		for ( i = 0; i < buffer; i++ ) {
 			this._buffer.push( 0.0 ); // initialize with zeros, but could be any value (we're just ensuring a contiguous block of memory)
 		}
 	} else if ( isCollection( buffer ) ) {
 		this._buffer = buffer;
 	} else {
 		throw new TypeError( 'invalid argument. Must provide either a valid buffer size (positive integer) or an array-like object which can serve as the underlying buffer. Value: `' + buffer + '`.' );
 	}
 	this._length = this._buffer.length;
 	this._count = 0;
 	this._i = -1;
 	return this;
 }
 
 /**
 * Clears the buffer.
 *
 * @name clear
 * @memberof CircularBuffer.prototype
 * @type {Function}
 * @returns {CircularBuffer} circular buffer instance
 *
 * @example
 * var b = new CircularBuffer( 2 );
 *
 * // Add values to the buffer:
 * b.push( 'foo' );
 * b.push( 'bar' );
 * b.push( 'beep' );
 * b.push( 'boop' );
 *
 * // Get the number of elements currently in the buffer:
 * var n = b.count;
 * // returns 2
 *
 * // Clear the buffer:
 * b.clear();
 *
 * // Get the number of buffer values:
 * n = b.count;
 * // returns 0
 */
 setReadOnly( CircularBuffer.prototype, 'clear', function clear() {
 	this._count = 0;
 	this._i = -1; // NOTE: this ensures that we always fill the buffer starting at index `0`.
 	return this;
 });
 
 /**
 * Number of elements currently in the buffer.
 *
 * @name count
 * @memberof CircularBuffer.prototype
 * @type {NonNegativeInteger}
 *
 * @example
 * var b = new CircularBuffer( 4 );
 *
 * // Get the value count:
 * var n = b.count;
 * // returns 0
 *
 * // Add values to the buffer:
 * b.push( 'foo' );
 * b.push( 'bar' );
 *
 * // Get the value count:
 * n = b.count;
 * // returns 2
 */
 setReadOnlyAccessor( CircularBuffer.prototype, 'count', function get() {
 	return this._count;
 });
 
 /**
 * Boolean indicating whether a circular buffer is full.
 *
 * @name full
 * @memberof CircularBuffer.prototype
 * @type {boolean}
 *
 * @example
 * var b = new CircularBuffer( 3 );
 *
 * // Determine if the buffer is full:
 * var bool = b.full;
 * // returns false
 *
 * // Add values to the buffer:
 * b.push( 'foo' );
 * b.push( 'bar' );
 * b.push( 'beep' );
 * b.push( 'boop' );
 *
 * // Determine if the buffer is full:
 * bool = b.full;
 * // returns true
 */
 setReadOnlyAccessor( CircularBuffer.prototype, 'full', function get() {
 	return this._count === this._length;
 });
 
 /**
 * Returns an iterator for iterating over a circular buffer.
 *
 * ## Notes
 *
 * -   An iterator does not iterate over partially full buffers.
 *
 * @name iterator
 * @memberof CircularBuffer.prototype
 * @type {Function}
 * @param {NonNegativeInteger} [niters] - number of iterations
 * @throws {TypeError} must provide a nonnegative integer
 * @returns {Iterator} iterator
 *
 * @example
 * var b = new CircularBuffer( 3 );
 *
 * // Add values to the buffer:
 * b.push( 'foo' );
 * b.push( 'bar' );
 * b.push( 'beep' );
 * b.push( 'boop' );
 *
 * // Create an iterator:
 * var it = b.iterator( b.length );
 *
 * // Iterate over the buffer...
 * var v = it.next().value;
 * // returns 'bar'
 *
 * v = it.next().value;
 * // returns 'beep'
 *
 * v = it.next().value;
 * // returns 'boop'
 *
 * var bool = it.next().done;
 * // returns true
 */
 setReadOnly( CircularBuffer.prototype, 'iterator', function iterator( niters ) {
 	var iter;
 	var self;
 	var FLG;
 	var N;
 	var n;
 	var i;
 
 	if ( arguments.length ) {
 		if ( !isNonNegativeInteger( niters ) ) {
 			throw new TypeError( 'invalid argument. Must provide a nonnegative integer. Value: `' + niters + '`.' );
 		}
 		N = niters;
 	} else {
 		N = MAX_ITERATIONS;
 	}
 	self = this;
 
 	// Initialize the iteration index and counter:
 	i = this._i;
 	n = 0;
 
 	// Create an iterator protocol-compliant object:
 	iter = {};
 	setReadOnly( iter, 'next', next );
 	setReadOnly( iter, 'return', end );
 	if ( iteratorSymbol ) {
 		setReadOnly( iter, iteratorSymbol, factory );
 	}
 	return iter;
 
 	/**
 	* Returns an iterator protocol-compliant object containing the next iterated value.
 	*
 	* @private
 	* @returns {Object} iterator protocol-compliant object
 	*/
 	function next() {
 		/* eslint-disable no-underscore-dangle */
 		n += 1;
 		if ( FLG || n > N ) {
 			return {
 				'done': true
 			};
 		}
 		// If the buffer is only partially full, don't allow iteration over "undefined" elements (this ensures similar behavior with `toArray()`)...
 		if ( self._count !== self._length ) {
 			FLG = true;
 			return {
 				'done': true
 			};
 		}
 		i = (i+1) % self._length;
 		return {
 			'value': self._buffer[ i ],
 			'done': false
 		};
 
 		/* eslint-enable no-underscore-dangle */
 	}
 
 	/**
 	* Finishes an iterator.
 	*
 	* @private
 	* @param {*} [value] - value to return
 	* @returns {Object} iterator protocol-compliant object
 	*/
 	function end( value ) {
 		FLG = true;
 		if ( arguments.length ) {
 			return {
 				'value': value,
 				'done': true
 			};
 		}
 		return {
 			'done': true
 		};
 	}
 
 	/**
 	* Returns a new iterator.
 	*
 	* @private
 	* @returns {Iterator} iterator
 	*/
 	function factory() {
 		return self.iterator( N );
 	}
 });
 
 /**
 * Circular buffer length (capacity).
 *
 * @name length
 * @memberof CircularBuffer.prototype
 * @type {NonNegativeInteger}
 *
 * @example
 * var b = new CircularBuffer( 4 );
 *
 * // Get the buffer capacity:
 * var len = b.length;
 * // returns 4
 */
 setReadOnlyAccessor( CircularBuffer.prototype, 'length', function get() {
 	return this._length;
 });
 
 /**
 * Adds a value to the circular buffer.
 *
 * @name push
 * @memberof CircularBuffer.prototype
 * @type {Function}
 * @returns {(*|void)} removed element or undefined
 *
 * @example
 * var b = new CircularBuffer( 3 );
 *
 * // Fill the buffer:
 * var v = b.push( 'foo' );
 * // returns undefined
 *
 * v = b.push( 'bar' );
 * // returns undefined
 *
 * v = b.push( 'beep' );
 * // returns undefined
 *
 * // Add another value to the buffer and return the removed element:
 * v = b.push( 'boop' );
 * // returns 'foo'
 */
 setReadOnly( CircularBuffer.prototype, 'push', function push( value ) {
 	var v;
 
 	// Compute the next buffer index:
 	this._i = (this._i+1) % this._length;
 
 	// Check if we are still filling the buffer...
 	if ( this._count < this._length ) {
 		this._buffer[ this._i ] = value;
 		this._count += 1;
 		return;
 	}
 	// Replace an existing buffer element...
 	v = this._buffer[ this._i ];
 	this._buffer[ this._i ] = value;
 	return v;
 });
 
 /**
 * Returns an array of circular buffer values.
 *
 * @name toArray
 * @memberof CircularBuffer.prototype
 * @type {Function}
 * @returns {Array} circular buffer values
 *
 * @example
 * var b = new CircularBuffer( 3 );
 *
 * // Add values to the buffer:
 * b.push( 'foo' );
 * b.push( 'bar' );
 * b.push( 'beep' );
 * b.push( 'boop' );
 *
 * // Get an array of buffer values:
 * var vals = b.toArray();
 * // returns [ 'bar', 'beep', 'boop' ]
 */
 setReadOnly( CircularBuffer.prototype, 'toArray', function toArray() {
 	var out;
 	var k;
 	var i;
 
 	out = [];
 	for ( i = 1; i <= this._count; i++ ) {
 		// Note: in a full buffer, `count == length`; in a partially full buffer, we need to ensure we always start at index `0`
 		k = (this._i+i) % this._count;
 		out.push( this._buffer[ k ] );
 	}
 	return out;
 });
 
 /**
 * Serializes a circular buffer as JSON.
 *
 * ## Notes
 *
 * -   `JSON.stringify()` implicitly calls this method when stringifying a `CircularBuffer` instance.
 *
 * @name toJSON
 * @memberof CircularBuffer.prototype
 * @type {Function}
 * @returns {Object} serialized circular buffer
 *
 * @example
 * var b = new CircularBuffer( 3 );
 *
 * // Add values to the buffer:
 * b.push( 'foo' );
 * b.push( 'bar' );
 * b.push( 'beep' );
 * b.push( 'boop' );
 *
 * // Serialize to JSON:
 * var o = b.toJSON();
 * // returns { 'type': 'circular-buffer', 'length': 3, 'data': [ 'bar', 'beep', 'boop' ] }
 */
 setReadOnly( CircularBuffer.prototype, 'toJSON', function toJSON() {
 	var out = {};
 	out.type = 'circular-buffer';
 	out.length = this._length;
 	out.data = this.toArray();
 	return out;
 });
 
 
 // EXPORTS //
 
 module.exports = CircularBuffer;