README

pipeline coverage

This libray expose basic encoders with a common interface.

Installation

composer require arnapou/encoder

packagist 👉️ arnapou/encoder

Book Encoders

These encoders are predictive encoders which offers great compression capabilities on a specific known book of words.

These encoders are bad for strings which are not in the book : they take 2 bytes instead of 1.

One byte encoder (8 bits)

Maximum number of words : 255

use Arnapou\Encoder\Book\ArrayBook;
use Arnapou\Encoder\Book\OneByteBookEncoder;

$book = new ArrayBook(['Hello', 'World']);
$encoder = new OneByteBookEncoder($book);

// 11 to 4 bytes (-63%)

var_dump(bin2hex($encoder->encode('Hello World')));
// string(8) "00ff2001"

var_dump($encoder->decode(hex2bin('00ff2001')));
// string(11) "Hello World"

Two bytes encoder (16 bits)

Maximum number of words : 65535

This is mostly usefull when you have a lot of words to store (> 256) and each of them is at least 2 bytes long.

use Arnapou\Encoder\Book\ArrayBook;
use Arnapou\Encoder\Book\TwoBytesBookEncoder;

$book = new ArrayBook(['https://', 'arnapou.net']);
$encoder = new TwoBytesBookEncoder($book);

// 19 to 4 bytes (-79%)

var_dump(bin2hex($encoder->encode('https://arnapou.net')));
// string(6) "00010000"

var_dump($encoder->decode(hex2bin('00010000')));
// string(19) "https://arnapou.net"

Example

You can use this encoder for shortening predefined text patterns.

I use it to shorten urls which are on the same patterns.

Look at available books in src/Book :

ArrayBook : simple implementation of generic iterable book
EnglishBook : built-in book for english text
WebBook : built-in book for URIs

Feel free to submit dedicated books.

use Arnapou\Encoder\Book\EnglishBook;
use Arnapou\Encoder\Book\OneByteBookEncoder;

$book = new EnglishBook();
$encoder = new OneByteBookEncoder($book);

// 22 to 11 bytes (-50%)

var_dump(bin2hex($encoder->encode('This is a small string')));
// string(11) "ff54446e5675aeac75d446"

var_dump($encoder->decode(hex2bin('ff54446e5675aeac75d446')));
// string(22) "This is a small string"

Miscellaneous Encoders

Your will find other useful encoders like

Encoder	Description
Identity	no encoding
Hexadecimal	hexadecimal encoding
Base64	encoding in base 64 with optional trimming
Base64UrlSafe	encoding in base 64 for urls (`+/` => `-_`)
Zlib	`gzdeflate`/`gzencode`/`gzcompress` family

And a PipelineEncoder which is very usefull to chain encoders :

use Arnapou\Encoder\Base64\Base64Encoder;
use Arnapou\Encoder\PipelineEncoder;
use Arnapou\Encoder\Zlib\ZlibEncoder;
use Arnapou\Encoder\Zlib\ZlibEncoding;

$encoder = new PipelineEncoder(
    new ZlibEncoder(encoding: ZlibEncoding::raw),
    new Base64Encoder(),
);

var_dump($encoder->encode('Lorem ipsum dolor sit amet'));
// string(38) "88kvSs1VyCwoLs1VSMnPyS9SKM4sUUjMTS0BAA"

var_dump($encoder->decode('88kvSs1VyCwoLs1VSMnPyS9SKM4sUUjMTS0BAA'));
// string(26) "Lorem ipsum dolor sit amet"

Php versions

Date	Ref	8.4	8.3	8.2
24/11/2024	2.3.x, main	×	×
25/11/2023	2.0 - 2.2		×
04/09/2024	1.3.x		×	×
13/12/2022	1.0 - 1.2			×

arnapou / encoder

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