Diff-Match-Patch

The Diff Match and Patch libraries offer robust algorithms to perform the operations required for synchronizing plain text:

• computes character-based diff of two texts
• performs fuzzy match of given string
• applies patches onto changed base text.

This is the port of google-diff-match-patch lib to PHP.

NOTE: This is alpha software and is under development.

Diff

Compare two plain text and efficiently return a array of differences. It works with characters, but if you want to compute word-based or line-based diff — you can easily tune it for your needs.

Usage:

<?php

use DiffMatchPatch\DiffMatchPatch;

$text1 = "The quick brown fox jumps over the lazy dog.";
$text2 = "That quick brown fox jumped over a lazy dog.";
$dmp = new DiffMatchPatch();
$diffs = $dmp->diff_main($text1, $text2, false);
var_dump($diffs);

Returns:

array(
    array(DiffMatchPatch::DIFF_EQUAL, "Th"),
    array(DiffMatchPatch::DIFF_DELETE, "e"),
    array(DiffMatchPatch::DIFF_INSERT, "at"),
    array(DiffMatchPatch::DIFF_EQUAL, " quick brown fox jump"),
    array(DiffMatchPatch::DIFF_DELETE, "s"),
    array(DiffMatchPatch::DIFF_INSERT, "ed"),
    array(DiffMatchPatch::DIFF_EQUAL, " over "),
    array(DiffMatchPatch::DIFF_DELETE, "the"),
    array(DiffMatchPatch::DIFF_INSERT, "a"),
    array(DiffMatchPatch::DIFF_EQUAL, " lazy dog."),
)

Demo

Match

Given a search string, find its best fuzzy match in a plain text near the given location. Weighted for both accuracy and location.

Usage:

<?php

use DiffMatchPatch\DiffMatchPatch;

$dmp = new DiffMatchPatch();
$text = "The quick brown fox jumps over the lazy fox.";
$pos = $dmp->match_main($text, "fox", 0); // Returns 16
$pos = $dmp->match_main($text, "fox", 40); // Returns 40
$pos = $dmp->match_main($text, "jmps"); // Returns 20
$pos = $dmp->match_main($text, "jmped"); // Returns -1
$pos = $dmp->Match_Threshold = 0.7;
$pos = $dmp->match_main($text, "jmped"); // Returns 20

Demo

Patch

Apply a list of patches in Unidiff-like format onto plain text. Use best-effort to apply patch even when the underlying text doesn't match.

Usage:

<?php

use DiffMatchPatch\DiffMatchPatch;

$dmp = new DiffMatchPatch();
$patches = $dmp->patch_make("The quick brown fox jumps over the lazy dog.", "That quick brown fox jumped over a lazy dog.");
// @@ -1,11 +1,12 @@
//  Th
// -e
// +at
//   quick b
// @@ -22,18 +22,17 @@
//  jump
// -s
// +ed
//   over
// -the
// +a
//   laz
$result = $dmp->patch_apply($patches, "The quick red rabbit jumps over the tired tiger.");
var_dump($result);

Returns:

array(
    "That quick red rabbit jumped over a tired tiger.",
    array (
        true,
        true,
    ),
);

Demo

API

Currently this lib available in PHP, Java, JavaScript, Dart, C++, C#, Objective C, Lua and Python. Regardless of language, each library features the same API and the same functionality. All versions also have comprehensive test harnesses.

Algorithms

This library implements Myer's diff algorithm which is generally considered to be the best general-purpose diff. A layer of pre-diff speedups and post-diff cleanups surround the diff algorithm, improving both performance and output quality.

This library also implements a Bitap matching algorithm at the heart of a flexible matching and patching strategy.

Requirements

• PHP 5.3+
• Composer

License

Diff-Match-Patch is licensed under the Apache License 2.0 - see the LICENSE file for details