236 lines
5.3 KiB
Markdown
236 lines
5.3 KiB
Markdown
|
<!--
|
||
|
|
||
|
@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.
|
||
|
|
||
|
-->
|
||
|
|
||
|
# ArrayBuffer
|
||
|
|
||
|
> [Constructor][mdn-arraybuffer] which returns an object used to represent a generic, fixed-length raw binary data buffer.
|
||
|
|
||
|
<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
|
||
|
|
||
|
<section class="intro">
|
||
|
|
||
|
</section>
|
||
|
|
||
|
<!-- /.intro -->
|
||
|
|
||
|
<!-- Package usage documentation. -->
|
||
|
|
||
|
<section class="usage">
|
||
|
|
||
|
## Usage
|
||
|
|
||
|
```javascript
|
||
|
var ArrayBuffer = require( '@stdlib/array/buffer' );
|
||
|
```
|
||
|
|
||
|
#### ArrayBuffer( size )
|
||
|
|
||
|
Returns an [`ArrayBuffer`][mdn-arraybuffer] having a specified number of bytes.
|
||
|
|
||
|
<!-- eslint-disable stdlib/require-globals -->
|
||
|
|
||
|
```javascript
|
||
|
var buf = new ArrayBuffer( 5 );
|
||
|
// returns <ArrayBuffer>
|
||
|
```
|
||
|
|
||
|
* * *
|
||
|
|
||
|
### Properties
|
||
|
|
||
|
#### ArrayBuffer.length
|
||
|
|
||
|
Number of input arguments the constructor accepts.
|
||
|
|
||
|
<!-- eslint-disable stdlib/require-globals -->
|
||
|
|
||
|
```javascript
|
||
|
var len = ArrayBuffer.length;
|
||
|
// returns 1
|
||
|
```
|
||
|
|
||
|
#### ArrayBuffer.prototype.byteLength
|
||
|
|
||
|
**Read-only** property which returns the length (in bytes) of the [`ArrayBuffer`][mdn-arraybuffer].
|
||
|
|
||
|
<!-- eslint-disable stdlib/require-globals -->
|
||
|
|
||
|
```javascript
|
||
|
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.
|
||
|
|
||
|
<!-- eslint-disable stdlib/require-globals -->
|
||
|
|
||
|
```javascript
|
||
|
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`][mdn-arraybuffer].
|
||
|
|
||
|
<!-- eslint-disable stdlib/require-globals -->
|
||
|
|
||
|
```javascript
|
||
|
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`][mdn-arraybuffer]. To beginning copying from a different byte index, provide a `start` argument, specifying the starting byte index (inclusive).
|
||
|
|
||
|
<!-- eslint-disable stdlib/require-globals -->
|
||
|
|
||
|
```javascript
|
||
|
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`][mdn-arraybuffer].
|
||
|
|
||
|
<!-- eslint-disable stdlib/require-globals -->
|
||
|
|
||
|
```javascript
|
||
|
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`][mdn-arraybuffer]. To copy until a particular byte index, provide an `end` index, specifying the ending byte index (exclusive).
|
||
|
|
||
|
<!-- eslint-disable stdlib/require-globals -->
|
||
|
|
||
|
```javascript
|
||
|
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`][mdn-arraybuffer].
|
||
|
|
||
|
<!-- eslint-disable stdlib/require-globals -->
|
||
|
|
||
|
```javascript
|
||
|
var b1 = new ArrayBuffer( 10 );
|
||
|
var b2 = b1.slice( 2, -2 );
|
||
|
|
||
|
var nbytes = b2.byteLength;
|
||
|
// returns 6
|
||
|
```
|
||
|
|
||
|
</section>
|
||
|
|
||
|
<!-- /.usage -->
|
||
|
|
||
|
* * *
|
||
|
|
||
|
<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
|
||
|
|
||
|
<section class="notes">
|
||
|
|
||
|
</section>
|
||
|
|
||
|
<!-- /.notes -->
|
||
|
|
||
|
<!-- Package usage examples. -->
|
||
|
|
||
|
<section class="examples">
|
||
|
|
||
|
## Examples
|
||
|
|
||
|
<!-- eslint no-undef: "error" -->
|
||
|
|
||
|
```javascript
|
||
|
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 ] ) );
|
||
|
}
|
||
|
```
|
||
|
|
||
|
</section>
|
||
|
|
||
|
<!-- /.examples -->
|
||
|
|
||
|
<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
|
||
|
|
||
|
<section class="references">
|
||
|
|
||
|
</section>
|
||
|
|
||
|
<!-- /.references -->
|
||
|
|
||
|
<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
|
||
|
|
||
|
<section class="links">
|
||
|
|
||
|
[mdn-arraybuffer]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer
|
||
|
|
||
|
</section>
|
||
|
|
||
|
<!-- /.links -->
|