@stdlib/array-buffer NPM

ArrayBuffer

Constructor which returns an object used to represent a generic, fixed-length raw binary data buffer.

Installation

npm install @stdlib/array-buffer

Usage

var ArrayBuffer = require( '@stdlib/array-buffer' );

ArrayBuffer( size )

Returns an ArrayBuffer having a specified number of bytes.

var buf = new ArrayBuffer( 5 );
// returns <ArrayBuffer>

Properties

ArrayBuffer.length

Number of input arguments the constructor accepts.

var len = ArrayBuffer.length;
// returns 1

ArrayBuffer.prototype.byteLength

Read-only property which returns the length (in bytes) of the ArrayBuffer.

var buf = new ArrayBuffer( 5 );
var byteLength = buf.byteLength;
// returns 5

Methods

ArrayBuffer.isView( arr )

Static method which returns a boolean indicating if provided a buffer view.

var Float64Array = require( '@stdlib/array-float64' );
var view = new Float64Array( 10 );

var bool = ArrayBuffer.isView( view );
// returns true

ArrayBuffer.prototype.slice( [start[, end]] )

Copies the bytes of an ArrayBuffer to a new ArrayBuffer.

var b1 = new ArrayBuffer( 10 );

var b2 = b1.slice();
// returns <ArrayBuffer>

var bool = ( b2 === b1 );
// returns false

By default, the method copies from the beginning of the ArrayBuffer. To beginning copying from a different byte index, provide a start argument, specifying the starting byte index (inclusive).

var b1 = new ArrayBuffer( 10 );
var b2 = b1.slice( 2 );

var nbytes = b2.byteLength;
// returns 8

If start < 0, the index is relative to the end of the ArrayBuffer.

var b1 = new ArrayBuffer( 10 );
var b2 = b1.slice( -2 );

var nbytes = b2.byteLength;
// returns 2

By default, the method copies to the end of the ArrayBuffer. To copy until a particular byte index, provide an end index, specifying the ending byte index (exclusive).

var b1 = new ArrayBuffer( 10 );
var b2 = b1.slice( 2, 6 );

var nbytes = b2.byteLength;
// returns 4

If end < 0, the index is relative to the end of the ArrayBuffer.

var b1 = new ArrayBuffer( 10 );
var b2 = b1.slice( 2, -2 );

var nbytes = b2.byteLength;
// returns 6

Examples

var randu = require( '@stdlib/random-base-randu' );
var Float64Array = require( '@stdlib/array-float64' );
var Uint8Array = require( '@stdlib/array-uint8' );
var toBinaryString = require( '@stdlib/number-uint8-base-to-binary-string' );
var ArrayBuffer = require( '@stdlib/array-buffer' );

var bytes;
var buf;
var arr;
var i;

// Create a new ArrayBuffer:
buf = new ArrayBuffer( 64 );

// Create a Float64 array buffer view:
arr = new Float64Array( buf.byteLength/8 );
for ( i = 0; i < arr.length; i++ ) {
    arr[ i ] = randu() * 100.0;
}

// Create a "bytes" view of the array buffer:
bytes = new Uint8Array( arr.buffer );

// Print the bytes:
for ( i = 0; i < bytes.length; i++ ) {
    console.log( 'byte %d: %s', i, toBinaryString( bytes[ i ] ) );
}

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.