# fifo-buffer

> A fast FIFO implementation purely based on Node Buffers

Latest version **1.0.0** (published 2017-03-09) · ISC license · 0 weekly downloads

## Install

```sh
npm install fifo-buffer
pnpm add fifo-buffer
yarn add fifo-buffer
bun add fifo-buffer
```

## Health

**Score 15/100 (F)** — status: abandoned.

Positive: no vulnerabilities.

Warnings: low downloads; no types; no esm support.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 1.0.0 |
| Published | 2017-03-09 |
| First published | 2017-03-09 |
| Weekly downloads | 0 |
| License | ISC |
| TypeScript types | none |
| Module format | CommonJS |
| Node | >=5.10 |
| Dependencies | 0 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Author | Christian H |
| Maintainers | chhu79 |
| Keywords | FIFO, buffer, socket, binary |

## Links

- npm: https://www.npmjs.com/package/fifo-buffer
- npm.io page: https://npm.io/package/fifo-buffer

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## Recent versions

- 1.0.0 (latest) — 2017-03-09

## README

# fifo.js

A simple fifo buffer for node-buffers. Excellent for handling encapsulated binary data in a TCP/IP stream. I encountered many situations where I needed to decode an embedded packet structure from a socket stream.

## Installation

As npm for Node.js:

```
$ npm install fifo-buffer
```

## Example
Some console interaction:
```
> FIFO=require('./fifo.js')
[Function: FIFOBuffer]
> b = new FIFO()
FIFOBuffer {
  buffer: <Buffer 00 00 00 00 00 00 00 00 00 ... >,
  high: 1048576,
  tail: 0,
  head: 0 }
> b.enq(Buffer.from([1,2,3,4]))
true
> b.enq(Buffer.from([5,6,7,8]))
true
> b.deq(2)
<Buffer 01 02>
> b.deq(2)
<Buffer 03 04>
> b.deq(2)
<Buffer 05 06>
> b.deq(2)
<Buffer 07 08>
> b.deq(2)
null
> b.enq(Buffer.from([1,2,3,4]))
true
> b.peek(2)
<Buffer 01 02>
> b.peek(2)
<Buffer 01 02>
> b.peek(5)
null
> b.size
4
>
```
A sample interface to extract a packet within a TCP/IP stream. Assuming socket is configured
to provide a buffer on "data". The encapsulated packet simply begins with a 4 byte header containing
its length.
```js
var FIFO = require('fifo-buffer');
var fifo = new FIFO();

// ... assuming socket setup and connected:
socket.on("data", (data) => {
   if (!fifo.enq(data))
      throw "No more space in FIFO!";
   let temp_buf;
   while (temp_buf = fifo.peek(4)) { // as long as there are 4 bytes in fifo (our header)
      let psize = temp_buf.readUInt32BE(); // we only deq complete packets so the first 4 bytes must be the length of the incoming packet.
      if (fifo.size < psize + 4)
         break;   // incomplete packet, try again next time we receive data.

      // EITHER remove header and give remaining packet to some handler:
      fifo.deq(4);   // trash 4 byte Header
      handleCompleteEncapsulatedPacket(fifo.deq(psize));
      // OR leave header in place:
      handleCompleteEncapsulatedPacket(fifo.deq(psize + 4));
   }
});
```

## API

### FIFOBuffer()

Initializes a new empty `FIFOBuffer` with the default capacity (1MByte).

### FIFOBuffer(capacity)

Initializes a new empty `FIFOBuffer` with the given `capacity`.

### FIFOBuffer#deq(n)

Dequeues the oldest n bytes of the FIFO buffer and returns a copy.
Returns `null` when the buffer has less bytes available.

### FIFOBuffer#enq(buffer)

Enqueues the `buffer` at the end and returns `true` when there was enough space.
When the buffer is full the method returns `false`.

### FIFOBuffer#peek(n)

Copies the oldest n bytes of the FIFO buffer. Does not change the state.
Returns `null` when the buffer has less bytes available.

### FIFOBuffer#size

Returns the current size of the FIFO.

## Testing

As npm package:

```
$ npm test
```

## Licence

ISC

---
_Source: https://npm.io/package/fifo-buffer · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._