https://github.com/codemix/malloc-append

Simple append-only alloc() implementation on top of buffers and array buffers.
https://github.com/codemix/malloc-append

Last synced: 9 months ago
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Simple append-only alloc() implementation on top of buffers and array buffers.

• Host: GitHub
• URL: https://github.com/codemix/malloc-append
• Owner: codemix
• License: mit
• Created: 2016-04-02T20:35:28.000Z (almost 10 years ago)
• Default Branch: master
• Last Pushed: 2016-04-02T20:37:12.000Z (almost 10 years ago)
• Last Synced: 2025-05-16T21:48:41.594Z (10 months ago)
• Language: JavaScript
• Size: 12.7 KB
• Stars: 1
• Watchers: 4
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

          
# malloc-append

An append-only memory allocator with the same interface as [malloc](https://github.com/codemix/malloc), useful for implementing append only logs. Has no `free()` but does not enforce write-once.

[![Build Status](https://travis-ci.org/codemix/malloc-append.svg?branch=master)](https://travis-ci.org/codemix/malloc-append)

## What?

It lets you allocate a large, contiguous slab of memory up front and then `alloc()` within that buffer.

It is mostly useful in conjunction with things like [mmap.js](https://github.com/indutny/mmap.js).

It's developed using [design by contract](https://github.com/codemix/babel-plugin-contracts), so you might find the library's own code style a bit unusual, but it doesn't affect usage or performance.

## Installation

Install via [npm](https://npmjs.org/package/malloc-append).

## Usage

```js

import Allocator from "malloc-append";

const heap = new Buffer(1024 * 1024);

const allocator = new Allocator(heap); // heap could also be an ArrayBuffer

console.log(allocator.inspect());

let firstAddress = 0;

let lastAddress = 0;

for (let i = 0; i < 100; i++) {

  const address = allocator.alloc(64);

  if (firstAddress === 0) {

    firstAddress = address;

  }

  if (lastAddress !== 0) {

    // do something with the address

    heap.writeUInt32LE(address, lastAddress);

  }

}

let address = firstAddress;

for (let i = 0; i < 100; i++) {

  console.log('Reading address', address);

  address = heap.readUInt32LE(address);

}

```

## License

Published by [codemix](http://codemix.com/) under a permissive MIT License, see [LICENSE.md](./LICENSE.md).