ModThree Library

A lightweight PHP library to compute the modulo three of a binary string using a Finite State Machine (FSM).

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Features

• Define states and transitions dynamically.
• Process input sequences and track state changes.
• Immutable and extensible design.
• PSR-12 compliant and easy to integrate.

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Installation

Install the library via Git:

git clone https://github.com/illmatix/modthree-challenge.git

Usage

Directly Use mod-three

use illmatix\modThree\ModThree;

$result = ModThree::calculate("1101"); // Binary 13 → Modulo 3 = 1
echo $result; // 1

Customize FSM Setup

If needed, you can directly use the FSM class for custom scenarios:

use illmatix\modThree\ModThreeFSM;
use illmatix\modThree\ModThreeState;
use illmatix\modThree\ModThreeTransition;

$fsm = new ModThreeFSM();

$s0 = new ModThreeState('S0');
$s1 = new ModThreeState('S1');
$s2 = new ModThreeState('S2');

$fsm->addState($s0);
$fsm->addState($s1);
$fsm->addState($s2);
$fsm->setInitialState($s0);

$fsm->addTransition(new ModThreeTransition($s0, '0', $s0));
$fsm->addTransition(new ModThreeTransition($s0, '1', $s1));
$fsm->addTransition(new ModThreeTransition($s1, '0', $s2));
$fsm->addTransition(new ModThreeTransition($s1, '1', $s0));
$fsm->addTransition(new ModThreeTransition($s2, '0', $s1));
$fsm->addTransition(new ModThreeTransition($s2, '1', $s2));

$fsm->processInput("1101"); // Binary 13
echo $fsm->getCurrentState()->getName(); // "S1"

Unit Tests

Run tests with PHPUnit:

vendor/bin/phpunit

or

composer test

Contributing

Contributions are welcome! Feel free to submit issues or pull requests.

License

This project is licensed under the MIT License.

Requirements

• PHP 8.4 or higher
• Composer
• Docker (optional)