Add Diff v3 backport (#7)

* add v3 "as-is"

composer.json

@@ -21,7 +21,7 @@
         "php": "^5.6 || ^7.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8.35 || ^5.4.3",
+        "phpunit/phpunit": "^5.7.23 || ^6.4.3",
         "symfony/process": "^3.3"
     },
     "autoload": {
@@ -33,6 +33,7 @@
         "psr-4": {
             "PhpCsFixer\\Diff\\v1_4\\Tests\\": "tests/v1_4",
             "PhpCsFixer\\Diff\\v2_0\\Tests\\": "tests/v2_0",
+            "PhpCsFixer\\Diff\\v3_0\\": "tests/v3_0",
             "PhpCsFixer\\Diff\\GeckoPackages\\DiffOutputBuilder\\Tests\\": "tests/GeckoPackages/DiffOutputBuilder/Tests",
             "PhpCsFixer\\Diff\\GeckoPackages\\DiffOutputBuilder\\Utils\\": "tests/GeckoPackages/DiffOutputBuilder/Utils"
         }

src/v1_4/Differ.php

@@ -232,7 +232,7 @@ public function diffToArray($from, $to, LongestCommonSubsequence $lcs = null)
 
         if ($this->detectUnmatchedLineEndings($fromMatches, $toMatches)) {
             $diff[] = array(
-                '#Warning: Strings contain different line endings!',
+                '#Warnings contain different line endings!',
                 0
             );
         }

src/v2_0/Differ.php

@@ -158,7 +158,7 @@ public function diffToArray($from, $to, LongestCommonSubsequenceCalculator $lcs
         }
 
         if ($this->detectUnmatchedLineEndings($diff)) {
-            \array_unshift($diff, ["#Warning: Strings contain different line endings!\n", 3]);
+            \array_unshift($diff, ["#Warnings contain different line endings!\n", 3]);
         }
 
         return $diff;

src/v3_0/Chunk.php

@@ -0,0 +1,78 @@
+<?php
+/*
+ * This file is part of sebastian/diff.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace PhpCsFixer\Diff\v3_0;
+
+final class Chunk
+{
+    /**
+     * @var int
+     */
+    private $start;
+
+    /**
+     * @var int
+     */
+    private $startRange;
+
+    /**
+     * @var int
+     */
+    private $end;
+
+    /**
+     * @var int
+     */
+    private $endRange;
+
+    /**
+     * @var array
+     */
+    private $lines;
+
+    public function __construct($start = 0, $startRange = 1, $end = 0, $endRange = 1, array $lines = [])
+    {
+        $this->start      = $start;
+        $this->startRange = $startRange;
+        $this->end        = $end;
+        $this->endRange   = $endRange;
+        $this->lines      = $lines;
+    }
+
+    public function getStart()
+    {
+        return $this->start;
+    }
+
+    public function getStartRange()
+    {
+        return $this->startRange;
+    }
+
+    public function getEnd()
+    {
+        return $this->end;
+    }
+
+    public function getEndRange()
+    {
+        return $this->endRange;
+    }
+
+    public function getLines()
+    {
+        return $this->lines;
+    }
+
+    public function setLines(array $lines)
+    {
+        $this->lines = $lines;
+    }
+}

src/v3_0/Diff.php

@@ -0,0 +1,67 @@
+<?php
+/*
+ * This file is part of sebastian/diff.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace PhpCsFixer\Diff\v3_0;
+
+final class Diff
+{
+    /**
+     * @var string
+     */
+    private $from;
+
+    /**
+     * @var string
+     */
+    private $to;
+
+    /**
+     * @var Chunk[]
+     */
+    private $chunks;
+
+    /**
+     * @param string  $from
+     * @param string  $to
+     * @param Chunk[] $chunks
+     */
+    public function __construct($from, $to, array $chunks = [])
+    {
+        $this->from   = $from;
+        $this->to     = $to;
+        $this->chunks = $chunks;
+    }
+
+    public function getFrom()
+    {
+        return $this->from;
+    }
+
+    public function getTo()
+    {
+        return $this->to;
+    }
+
+    /**
+     * @return Chunk[]
+     */
+    public function getChunks()
+    {
+        return $this->chunks;
+    }
+
+    /**
+     * @param Chunk[] $chunks
+     */
+    public function setChunks(array $chunks)
+    {
+        $this->chunks = $chunks;
+    }
+}