composer/semver
===============

Semver (Semantic Versioning) library that offers utilities, version constraint parsing and validation.

Originally written as part of [composer/composer](https://github.com/composer/composer),
now extracted and made available as a stand-alone library.

[![Continuous Integration](https://github.com/composer/semver/workflows/Continuous%20Integration/badge.svg?branch=main)](https://github.com/composer/semver/actions)


Installation
------------

Install the latest version with:

```bash
$ composer require composer/semver
```


Requirements
------------

* PHP 5.3.2 is required but using the latest version of PHP is highly recommended.


Version Comparison
------------------

For details on how versions are compared, refer to the [Versions](https://getcomposer.org/doc/articles/versions.md)
article in the documentation section of the [getcomposer.org](https://getcomposer.org) website.


Basic usage
-----------

### Comparator

The [`Composer\Semver\Comparator`](https://github.com/composer/semver/blob/main/src/Comparator.php) class provides the following methods for comparing versions:

* greaterThan($v1, $v2)
* greaterThanOrEqualTo($v1, $v2)
* lessThan($v1, $v2)
* lessThanOrEqualTo($v1, $v2)
* equalTo($v1, $v2)
* notEqualTo($v1, $v2)

Each function takes two version strings as arguments and returns a boolean. For example:

```php
use Composer\Semver\Comparator;

Comparator::greaterThan('1.25.0', '1.24.0'); // 1.25.0 > 1.24.0
```

### Semver

The [`Composer\Semver\Semver`](https://github.com/composer/semver/blob/main/src/Semver.php) class provides the following methods:

* satisfies($version, $constraints)
* satisfiedBy(array $versions, $constraint)
* sort($versions)
* rsort($versions)

### Intervals

The [`Composer\Semver\Intervals`](https://github.com/composer/semver/blob/main/src/Intervals.php) static class provides
a few utilities to work with complex constraints or read version intervals from a constraint:

```php
use Composer\Semver\Intervals;

// Checks whether $candidate is a subset of $constraint
Intervals::isSubsetOf(ConstraintInterface $candidate, ConstraintInterface $constraint);

// Checks whether $a and $b have any intersection, equivalent to $a->matches($b)
Intervals::haveIntersections(ConstraintInterface $a, ConstraintInterface $b);

// Optimizes a complex multi constraint by merging all intervals down to the smallest
// possible multi constraint. The drawbacks are this is not very fast, and the resulting
// multi constraint will have no human readable prettyConstraint configured on it
Intervals::compactConstraint(ConstraintInterface $constraint);

// Creates an array of numeric intervals and branch constraints representing a given constraint
Intervals::get(ConstraintInterface $constraint);

// Clears the memoization cache when you are done processing constraints
Intervals::clear()
```

See the class docblocks for more details.


License
-------

composer/semver is licensed under the MIT License, see the LICENSE file for details.
