Diff implementation for PHP, factored out of PHPUnit into a stand-alone component.
## Installation
You can add this library as a local, per-project dependency to your project using [Composer](https://getcomposer.org/):
```
composer require sebastian/diff
```
If you only need this library during development, for instance to run your project's test suite, then you should add it as a development-time dependency:
```
composer require --dev sebastian/diff
```
### Usage
#### Generating diff
The `Differ` class can be used to generate a textual representation of the difference between two strings:
```php
<?php
use SebastianBergmann\Diff\Differ;
$differ = new Differ;
print $differ->diff('foo', 'bar');
```
The code above yields the output below:
```diff
--- Original
+++ New
@@ @@
-foo
+bar
```
There are three output builders available in this package:
#### UnifiedDiffOutputBuilder
This is default builder, which generates the output close to udiff and is used by PHPUnit.
```php
<?php
use SebastianBergmann\Diff\Differ;
use SebastianBergmann\Diff\Output\UnifiedDiffOutputBuilder;
$builder = new UnifiedDiffOutputBuilder(
"--- Original\n+++ New\n", // custom header
false // do not add line numbers to the diff
);
$differ = new Differ($builder);
print $differ->diff('foo', 'bar');
```
#### StrictUnifiedDiffOutputBuilder
Generates (strict) Unified diff's (unidiffs) with hunks,
similar to `diff -u` and compatible with `patch` and `git apply`.
```php
<?php
use SebastianBergmann\Diff\Differ;
use SebastianBergmann\Diff\Output\StrictUnifiedDiffOutputBuilder;
$builder = new StrictUnifiedDiffOutputBuilder([
'collapseRanges' => true, // ranges of length one are rendered with the trailing `,1`
'commonLineThreshold' => 6, // number of same lines before ending a new hunk and creating a new one (if needed)
'contextLines' => 3, // like `diff: -u, -U NUM, --unified[=NUM]`, for patch/git apply compatibility best to keep at least @ 3
Note: If the chunk size is 0 lines, i.e., `getStartRange()` or `getEndRange()` return 0, the number of line returned by `getStart()` or `getEnd()` is one lower than one would expect. It is the line number after which the chunk should be inserted or deleted; in all other cases, it gives the first line number of the replaced range of lines.
