Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/stdlib-js/wasm-base-arrays2ptrs

Convert a list of arrays to pointers (i.e., byte offsets) in WebAssembly module memory.
https://github.com/stdlib-js/wasm-base-arrays2ptrs

javascript memory node node-js nodejs stdlib util utilities utility utils wasm webassembly

Last synced: 8 days ago
JSON representation

Convert a list of arrays to pointers (i.e., byte offsets) in WebAssembly module memory.

Awesome Lists containing this project

README

        


About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.


The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.


When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.


To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

# arrays2ptrs

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]

> Convert a list of arrays to "pointers" (i.e., byte offsets) in WebAssembly [module memory][@stdlib/wasm/memory].

## Installation

```bash
npm install @stdlib/wasm-base-arrays2ptrs
```

Alternatively,

- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).

The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

## Usage

```javascript
var arrays2ptrs = require( '@stdlib/wasm-base-arrays2ptrs' );
```

#### arrays2ptrs( ctx, arrays )

Converts a list of arrays to "pointers" (i.e., byte offsets) in WebAssembly [module memory][@stdlib/wasm/memory].

```javascript
var defineProperty = require( '@stdlib/utils-define-property' );
var ArrayBuffer = require( '@stdlib/array-buffer' );
var DataView = require( '@stdlib/array-dataview' );

var buf = new ArrayBuffer( 64*1024 ); // 64KiB

function isView( arr ) {
return ( arr.buffer === buf );
}

function realloc( nbytes ) {
buf = new ArrayBuffer( nbytes );
}

function view() {
return new DataView( buf );
}

var ctx = {
'isView': isView,
'realloc': realloc
};

defineProperty( ctx, 'view', {
'configurable': false,
'enumerable': true,
'get': view
});

// ...

var xobj = {
'dtype': 'generic',
'wdtype': 'float64',
'length': 2,
'data': [ 1.0, 2.0 ],
'stride': 1,
'offset': 0
};
var yobj = {
'dtype': 'generic',
'wdtype': 'float64',
'length': 2,
'data': [ 3.0, 4.0 ],
'stride': 1,
'offset': 0
};

// ...

var ptrs = arrays2ptrs( ctx, [ xobj, yobj ] );
// returns [...]
```

Each element in the list of input arrays should have the following properties:

- **dtype**: array [data type][@stdlib/array/dtypes].
- **wdtype**: WebAssembly [array data type][@stdlib/wasm/base/array2dtype].
- **length**: number of indexed elements.
- **data**: original array-like object.
- **stride**: index increment.
- **offset**: index offset.

In addition to each element's existing properties, each element of the returned array has the following additional properties:

- **BYTES_PER_ELEMENT**: number of bytes per element.
- **ptr**: byte offset.
- **nbytes**: number of bytes consumed by **indexed** array elements as stored in module memory.
- **copy**: boolean indicating whether an array had to be copied to module memory.

## Notes

- Beware that this function may reallocate module memory, resulting in [`ArrayBuffer`][@stdlib/array/buffer] detachment and the invalidation of any typed array views which were views of the previously allocated memory. Additionally, this function may write to module memory and does so without regard for any existing memory content. Users are thus encouraged to take suitable precautions (e.g., copying results out of module memory prior to subsequent invocation) in order to avoid unexpected results.
- If an array's data is copied to module memory, the data is copied to a contiguous segment of module memory, and the respective array object in the returned array will have unit stride and an offset of zero.

## Examples

```javascript
var setReadOnlyAccessor = require( '@stdlib/utils-define-nonenumerable-read-only-accessor' );
var setReadOnly = require( '@stdlib/utils-define-nonenumerable-read-only-property' );
var ArrayBuffer = require( '@stdlib/array-buffer' );
var DataView = require( '@stdlib/array-dataview' );
var Float64Array = require( '@stdlib/array-float64' );
var dtype2wasm = require( '@stdlib/wasm-base-dtype2wasm' );
var arrays2ptrs = require( '@stdlib/wasm-base-arrays2ptrs' );

function Context() {
this._buffer = new ArrayBuffer( 100 );
return this;
}

setReadOnly( Context.prototype, 'isView', function isView( arr ) {
return ( arr.buffer ) ? ( arr.buffer === this._buffer ) : false;
});

setReadOnly( Context.prototype, 'realloc', function realloc( nbytes ) {
this._buffer = new ArrayBuffer( nbytes );
});

setReadOnlyAccessor( Context.prototype, 'view', function getter() {
return new DataView( this._buffer );
});

// ...

var ctx = new Context();

// ...

var x = new Float64Array( 4 );
var y = new Float64Array( 4 );

// ...

var xobj = {
'dtype': 'float64',
'wdtype': dtype2wasm( 'float64' ),
'length': x.length,
'data': x,
'stride': 1,
'offset': 0
};

var yobj = {
'dtype': 'float64',
'wdtype': dtype2wasm( 'float64' ),
'length': y.length,
'data': y,
'stride': 1,
'offset': 0
};

var out = arrays2ptrs( ctx, [ xobj, yobj ] );
// returns [...]

console.log( out );
```

* * *

## Notice

This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].

## Copyright

Copyright © 2016-2024. The Stdlib [Authors][stdlib-authors].

[npm-image]: http://img.shields.io/npm/v/@stdlib/wasm-base-arrays2ptrs.svg
[npm-url]: https://npmjs.org/package/@stdlib/wasm-base-arrays2ptrs

[test-image]: https://github.com/stdlib-js/wasm-base-arrays2ptrs/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/wasm-base-arrays2ptrs/actions/workflows/test.yml?query=branch:main

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/wasm-base-arrays2ptrs/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/wasm-base-arrays2ptrs?branch=main

[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im

[stdlib]: https://github.com/stdlib-js/stdlib

[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors

[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

[deno-url]: https://github.com/stdlib-js/wasm-base-arrays2ptrs/tree/deno
[deno-readme]: https://github.com/stdlib-js/wasm-base-arrays2ptrs/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/wasm-base-arrays2ptrs/tree/umd
[umd-readme]: https://github.com/stdlib-js/wasm-base-arrays2ptrs/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/wasm-base-arrays2ptrs/tree/esm
[esm-readme]: https://github.com/stdlib-js/wasm-base-arrays2ptrs/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/wasm-base-arrays2ptrs/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/wasm-base-arrays2ptrs/main/LICENSE

[@stdlib/wasm/memory]: https://github.com/stdlib-js/wasm-memory

[@stdlib/wasm/base/array2dtype]: https://github.com/stdlib-js/wasm-base-array2dtype

[@stdlib/array/dtypes]: https://github.com/stdlib-js/array-dtypes

[@stdlib/array/buffer]: https://github.com/stdlib-js/array-buffer