@stdlib/array-shared-buffer NPM

SharedArrayBuffer

Constructor returning an object used to represent a generic, fixed-length raw binary data buffer which can be used to create views of shared memory.

Installation

npm install @stdlib/array-shared-buffer

Usage

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

SharedArrayBuffer( size )

Returns a SharedArrayBuffer having a specified number of bytes.

try {
    var buf = new SharedArrayBuffer( 5 );
    // returns <SharedArrayBuffer>
} catch ( err ) {
    console.log( 'Environment does not support SharedArrayBuffers.' );
}

Properties

SharedArrayBuffer.length

Number of input arguments the constructor accepts.

var len = SharedArrayBuffer.length;
// returns 1

SharedArrayBuffer.prototype.byteLength

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

try {
    var buf = new SharedArrayBuffer( 5 );
    var byteLength = buf.byteLength;
    // returns 5
} catch ( err ) {
    console.log( 'Environment does not support SharedArrayBuffers.' );
}

Methods

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

Copies the bytes of a SharedArrayBuffer to a new SharedArrayBuffer.

try {
    var b1 = new SharedArrayBuffer( 10 );

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

    var bool = ( b2 === b1 );
    // returns false
} catch ( err ) {
    console.log( 'Environment does not support SharedArrayBuffers.' );
}

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

try {
    var b1 = new SharedArrayBuffer( 10 );
    var b2 = b1.slice( 2 );

    var nbytes = b2.byteLength;
    // returns 8
} catch ( err ) {
    console.log( 'Environment does not support SharedArrayBuffers.' );
}

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

try {
    var b1 = new SharedArrayBuffer( 10 );
    var b2 = b1.slice( -2 );

    var nbytes = b2.byteLength;
    // returns 2
} catch ( err ) {
    console.log( 'Environment does not support SharedArrayBuffers.' );
}

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

try {
    var b1 = new SharedArrayBuffer( 10 );
    var b2 = b1.slice( 2, 6 );

    var nbytes = b2.byteLength;
    // returns 4
} catch ( err ) {
    console.log( 'Environment does not support SharedArrayBuffers.' );
}

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

try {
    var b1 = new SharedArrayBuffer( 10 );
    var b2 = b1.slice( 2, -2 );

    var nbytes = b2.byteLength;
    // returns 6
} catch ( err ) {
    console.log( 'Environment does not support SharedArrayBuffers.' );
}

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 SharedArrayBuffer = require( '@stdlib/array-shared-buffer' );

function main() {
    var bytes;
    var buf;
    var arr;
    var i;

    // Create a new SharedArrayBuffer:
    buf = new SharedArrayBuffer( 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 ] ) );
    }
}

try {
    main();
} catch ( err ) {
    console.error( 'Environment does not provide SharedArrayBuffer support.' );
}

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.