# php-diff
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[](https://github.com/jfcherng/php-diff/blob/v6/LICENSE)
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A comprehensive library for generating diff between two strings.
## Introduction
Generated diff can be rendered in all of the standard formats including:
**Text** renderers:
- Context
- Json (plain text)
- Unified
**HTML** renderers:
- Combined
- Inline
- Json (HTML)
- Side by Side
Note that for HTML rendered results, you have to add CSS for a better visualization.
You may modify one from `example/diff-table.css` or write your own from zero.
If you are okay with the default CSS, there is `\Jfcherng\Diff\DiffHelper::getStyleSheet()`
which can be used to get the content of the `example/diff-table.css`.
## Requirements
## Installation
This package is available on `Packagist` by the name of [jfcherng/php-diff](https://packagist.org/packages/jfcherng/php-diff).
```bash
composer require jfcherng/php-diff
```
## Example
See files and readme in the [example/](https://github.com/jfcherng/php-diff/blob/v6/example) directory.
```php
3,
// ignore case difference
'ignoreCase' => false,
// ignore line ending difference
'ignoreLineEnding' => false,
// ignore whitespace difference
'ignoreWhitespace' => false,
// if the input sequence is too long, it will just gives up (especially for char-level diff)
'lengthLimit' => 2000,
];
// the renderer class options
$rendererOptions = [
// how detailed the rendered HTML in-line diff is? (none, line, word, char)
'detailLevel' => 'line',
// renderer language: eng, cht, chs, jpn, ...
// or an array which has the same keys with a language file
// check the "Custom Language" section in the readme for more advanced usage
'language' => 'eng',
// show line numbers in HTML renderers
'lineNumbers' => true,
// show a separator between different diff hunks in HTML renderers
'separateBlock' => true,
// show the (table) header
'showHeader' => true,
// the frontend HTML could use CSS "white-space: pre;" to visualize consecutive whitespaces
// but if you want to visualize them in the backend with " ", you can set this to true
'spacesToNbsp' => false,
// HTML renderer tab width (negative = do not convert into spaces)
'tabSize' => 4,
// this option is currently only for the Combined renderer.
// it determines whether a replace-type block should be merged or not
// depending on the content changed ratio, which values between 0 and 1.
'mergeThreshold' => 0.8,
// this option is currently only for the Unified and the Context renderers.
// RendererConstant::CLI_COLOR_AUTO = colorize the output if possible (default)
// RendererConstant::CLI_COLOR_ENABLE = force to colorize the output
// RendererConstant::CLI_COLOR_DISABLE = force not to colorize the output
'cliColorization' => RendererConstant::CLI_COLOR_AUTO,
// this option is currently only for the Json renderer.
// internally, ops (tags) are all int type but this is not good for human reading.
// set this to "true" to convert them into string form before outputting.
'outputTagAsString' => false,
// this option is currently only for the Json renderer.
// it controls how the output JSON is formatted.
// see available options on https://www.php.net/manual/en/function.json-encode.php
'jsonEncodeFlags' => \JSON_UNESCAPED_SLASHES | \JSON_UNESCAPED_UNICODE,
// this option is currently effective when the "detailLevel" is "word"
// characters listed in this array can be used to make diff segments into a whole
// for example, making "good-looking" into "good-looking"
// this should bring better readability but set this to empty array if you do not want it
'wordGlues' => [' ', '-'],
// change this value to a string as the returned diff if the two input strings are identical
'resultForIdenticals' => null,
// extra HTML classes added to the DOM of the diff container
'wrapperClasses' => ['diff-wrapper'],
];
// one-line simply compare two files
$result = DiffHelper::calculateFiles($oldFile, $newFile, $rendererName, $differOptions, $rendererOptions);
// one-line simply compare two strings
$result = DiffHelper::calculate($old, $new, $rendererName, $differOptions, $rendererOptions);
// or even shorter if you are happy with default options
$result = DiffHelper::calculate($old, $new, $rendererName);
// custom usage
$differ = new Differ(explode("\n", $old), explode("\n", $new), $differOptions);
$renderer = RendererFactory::make($rendererName, $rendererOptions); // or your own renderer object
$result = $renderer->render($differ);
// use the JSON result to render in HTML
$jsonResult = DiffHelper::calculate($old, $new, 'Json'); // may store the JSON result in your database
$htmlRenderer = RendererFactory::make('Inline', $rendererOptions);
$result = $htmlRenderer->renderArray(json_decode($jsonResult, true));
```
## Rendered Results
### HTML Diff In-line Detailed Rendering
| None-level |
Line-level (Default) |
 |
 |
| Word-level |
Char-level |
 |
 |
### Renderer: Inline
```php
'line'];
```
### Renderer: Side By Side
```php
'line'];
```
### Renderer: Combined
```php
'word'];
```
This renderer is suitable for articles and always has no line number information.
### Renderer: Unified
About the `Unified` diff format: https://en.wikipedia.org/wiki/Diff#Unified_format
```diff
@@ -1,3 +1,4 @@
-Hello World!
+Hello World!
~~~~~~~~~~~~~~~~~~~
+Let's add a new line here.
X
@@ -7,6 +8,5 @@
N
-Do you know in Chinese, "金槍魚罐頭" means tuna can.
+Do you know in Japanese, "魚の缶詰" means fish can.
This is just a useless line.
G
-// remember to delete this line
Say hello to my neighbors.
```
### Renderer: Context
About the `Context` diff format: https://en.wikipedia.org/wiki/Diff#Context_format
Click to expand
```diff
***************
*** 1,3 ****
! Hello World!
~~~~~~~~~~~~~~~~~~~
X
--- 1,4 ----
! Hello World!
~~~~~~~~~~~~~~~~~~~
+ Let's add a new line here.
X
***************
*** 7,12 ****
N
! Do you know in Chinese, "金槍魚罐頭" means tuna can.
This is just a useless line.
G
- // remember to delete this line
Say hello to my neighbors.
--- 8,12 ----
N
! Do you know in Japanese, "魚の缶詰" means fish can.
This is just a useless line.
G
Say hello to my neighbors.
```
Click to expand
```json
[
[
{
"tag": "rep",
"old": {
"offset": 0,
"lines": ["Hello World! Good-looking.
"]
},
"new": {
"offset": 0,
"lines": ["Hello World! Bad-tempered.
"]
}
},
{
"tag": "eq",
"old": {
"offset": 1,
"lines": ["~~~~~~~~~~~~~~~~~~~"]
},
"new": {
"offset": 1,
"lines": ["~~~~~~~~~~~~~~~~~~~"]
}
},
{
"tag": "ins",
"old": {
"offset": 2,
"lines": []
},
"new": {
"offset": 2,
"lines": ["Let's add a new line here."]
}
},
{
"tag": "eq",
"old": {
"offset": 2,
"lines": ["X"]
},
"new": {
"offset": 3,
"lines": ["X"]
}
}
],
[
{
"tag": "eq",
"old": {
"offset": 6,
"lines": ["N"]
},
"new": {
"offset": 7,
"lines": ["N"]
}
},
{
"tag": "rep",
"old": {
"offset": 7,
"lines": ["Do you know in Chinese, \"金槍魚罐頭\" means tuna can."]
},
"new": {
"offset": 8,
"lines": ["Do you know in Japanese, \"魚の缶詰\" means fish can."]
}
},
{
"tag": "eq",
"old": {
"offset": 8,
"lines": ["\t \tTab visualization test.", "G"]
},
"new": {
"offset": 9,
"lines": ["\t \tTab visualization test.", "G"]
}
},
{
"tag": "del",
"old": {
"offset": 10,
"lines": ["// remember to delete this line"]
},
"new": {
"offset": 11,
"lines": []
}
},
{
"tag": "eq",
"old": {
"offset": 11,
"lines": ["Say hello to my neighbors."]
},
"new": {
"offset": 11,
"lines": ["Say hello to my neighbors."]
}
}
],
[
{
"tag": "eq",
"old": {
"offset": 14,
"lines": ["B"]
},
"new": {
"offset": 14,
"lines": ["B"]
}
},
{
"tag": "rep",
"old": {
"offset": 15,
"lines": ["Donec rutrum."]
},
"new": {
"offset": 15,
"lines": ["Donec rutrum test.", "There is a new inserted line."]
}
},
{
"tag": "eq",
"old": {
"offset": 16,
"lines": ["C"]
},
"new": {
"offset": 17,
"lines": ["C"]
}
},
{
"tag": "rep",
"old": {
"offset": 17,
"lines": ["Sed dictum lorem ipsum."]
},
"new": {
"offset": 18,
"lines": ["Sed dolor lorem ipsum hendrerit."]
}
},
{
"tag": "eq",
"old": {
"offset": 18,
"lines": [""]
},
"new": {
"offset": 19,
"lines": [""]
}
}
]
]
```
Click to expand
```json
[
[
{
"tag": "rep",
"old": {
"offset": 0,
"lines": ["<p>Hello World! Good-looking.</p>"]
},
"new": {
"offset": 0,
"lines": ["<div>Hello World! Bad-tempered.</div>"]
}
},
{
"tag": "eq",
"old": {
"offset": 1,
"lines": ["~~~~~~~~~~~~~~~~~~~"]
},
"new": {
"offset": 1,
"lines": ["~~~~~~~~~~~~~~~~~~~"]
}
},
{
"tag": "ins",
"old": {
"offset": 2,
"lines": [""]
},
"new": {
"offset": 2,
"lines": ["Let's add a new line here."]
}
},
{
"tag": "eq",
"old": {
"offset": 2,
"lines": ["X"]
},
"new": {
"offset": 3,
"lines": ["X"]
}
}
],
[
{
"tag": "eq",
"old": {
"offset": 6,
"lines": ["N"]
},
"new": {
"offset": 7,
"lines": ["N"]
}
},
{
"tag": "rep",
"old": {
"offset": 7,
"lines": ["Do you know in Chinese, \"金槍魚罐頭\" means tuna can."]
},
"new": {
"offset": 8,
"lines": ["Do you know in Japanese, \"魚の缶詰\" means fish can."]
}
},
{
"tag": "eq",
"old": {
"offset": 8,
"lines": ["\t \tTab visualization test.", "G"]
},
"new": {
"offset": 9,
"lines": ["\t \tTab visualization test.", "G"]
}
},
{
"tag": "del",
"old": {
"offset": 10,
"lines": ["// remember to delete this line"]
},
"new": {
"offset": 11,
"lines": [""]
}
},
{
"tag": "eq",
"old": {
"offset": 11,
"lines": ["Say hello to my neighbors."]
},
"new": {
"offset": 11,
"lines": ["Say hello to my neighbors."]
}
}
],
[
{
"tag": "eq",
"old": {
"offset": 14,
"lines": ["B"]
},
"new": {
"offset": 14,
"lines": ["B"]
}
},
{
"tag": "rep",
"old": {
"offset": 15,
"lines": ["Donec rutrum."]
},
"new": {
"offset": 15,
"lines": ["Donec rutrum test.", "There is a new inserted line."]
}
},
{
"tag": "eq",
"old": {
"offset": 16,
"lines": ["C"]
},
"new": {
"offset": 17,
"lines": ["C"]
}
},
{
"tag": "rep",
"old": {
"offset": 17,
"lines": ["Sed dictum lorem ipsum."]
},
"new": {
"offset": 18,
"lines": ["Sed dolor lorem ipsum hendrerit."]
}
},
{
"tag": "eq",
"old": {
"offset": 18,
"lines": [""]
},
"new": {
"offset": 19,
"lines": [""]
}
}
]
]
```