Strip inline data URIs before conversion to avoid backtrack limit failures

src/Html2Text.php

@@ -360,6 +360,10 @@ protected function doConvert()
             $text = trim($this->html);
         }
 
+        // Inline data URIs (e.g. base64 images) never end up in the text, and very
+        // long ones exhaust the PCRE backtrack limit of the patterns below (#130)
+        $text = preg_replace('/(<img\b[^>]*?\ssrc\s*=\s*)(["\'])data:[^"\']*+\2/i', '$1$2$2', $text);
+
         $this->converter($text);
 
         if ($this->linkList) {

test/DataUriTest.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Html2Text;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Large inline data URIs must not exhaust the PCRE backtrack limit (#130).
+ */
+class DataUriTest extends TestCase
+{
+    public function dataUriDataProvider()
+    {
+        $image = 'data:image/png;base64,' . str_repeat('QUJDREVGR0g', 120000);
+
+        return array(
+            'Image in list item' => array(
+                'html' => '<ul><li>Item <img src="' . $image . '"></li></ul>',
+                'expected' => '* Item',
+            ),
+            'Image in link' => array(
+                'html' => '<a href="https://example.com"><img src="' . $image . '"></a> text',
+                'expected' => '[https://example.com] text',
+            ),
+            'Image with alt tag in paragraph' => array(
+                'html' => '<p>Hello <img src="' . $image . '" alt="logo"> world</p>',
+                'expected' => 'Hello [logo] world',
+            ),
+        );
+    }
+
+    /**
+     * @dataProvider dataUriDataProvider
+     */
+    public function testDataUri($html, $expected)
+    {
+        $html2text = new Html2Text($html);
+        $this->assertEquals($expected, trim($html2text->getText()));
+    }
+}