Development

local-tests/concatenate.php

@@ -2,6 +2,8 @@
 
 set_time_limit(120);
 ini_set('memory_limit', '512M');
+error_reporting(E_ALL);
+ini_set('display_errors', 1);
 
 
 $fpdiLegacy = __DIR__ . '/../../FPDI/classes/fpdi.php';

src/FpdiTrait.php

@@ -129,7 +129,7 @@ protected function setMinPdfVersion($pdfVersion)
      */
     protected function getPdfParserInstance(StreamReader $streamReader, array $parserParams = [])
     {
-        // note: if you get an exception here - turn off errors/warnings on not found for your autoloader.
+        // note: if you get an exception here - turn off errors/warnings on not found classes for your autoloader.
         // psr-4 (https://www.php-fig.org/psr/psr-4/) says: Autoloader implementations MUST NOT throw
         // exceptions, MUST NOT raise errors of any level, and SHOULD NOT return a value.
         /** @noinspection PhpUndefinedClassInspection */

src/PdfParser/CrossReference/CrossReference.php

@@ -69,7 +69,7 @@ public function __construct(PdfParser $parser, $fileHeaderOffset = 0)
                 // sometimes the file header offset is part of the byte offsets, so let's retry by resetting it to zero.
                 if ($e->getCode() === CrossReferenceException::INVALID_DATA && $this->fileHeaderOffset !== 0) {
                     $this->fileHeaderOffset = 0;
-                    $reader = $this->readXref($offset + $this->fileHeaderOffset);
+                    $reader = $this->readXref($offset);
                 } else {
                     throw $e;
                 }

src/PdfParser/Filter/Flate.php

@@ -55,21 +55,10 @@ public function decode($data)
                     return $data;
                 }
 
-                // Try this fallback
-                $tries = 0;
+                // Try this fallback (remove the zlib stream header)
+                $data = @(gzinflate(substr($oData, 2)));
 
-                $oDataLen = strlen($oData);
-                while ($tries < 6 && ($data === false || (strlen($data) < ($oDataLen - $tries - 1)))) {
-                    $data = @(gzinflate(substr($oData, $tries)));
-                    $tries++;
-                }
-
-                // let's use this fallback only if the $data is longer than the original data
-                if (strlen($data) > ($oDataLen - $tries - 1)) {
-                    return $data;
-                }
-
-                if (!$data) {
+                if ($data === false) {
                     throw new FlateException(
                         'Error while decompressing stream.',
                         FlateException::DECOMPRESS_ERROR

tests/functional/PdfParser/Filter/FlateTest.php

@@ -42,6 +42,10 @@ public function decodeProvider()
             [
                 file_get_contents(__DIR__ . '/_files/Flate/special.bin'),
                 file_get_contents(__DIR__ . '/_files/Flate/special-decoded.bin'),
+            ],
+            [
+                "\x48\x89\x03\x00",
+                ''
             ]
         );
     }
@@ -55,7 +59,11 @@ public function testDecode($in, $expected)
 
         $decoded = $filter->decode($in);
 
-        $this->assertStringStartsWith($expected, $decoded);
+        if ($expected === '') {
+            $this->assertSame('', $decoded);
+        } else {
+            $this->assertStringStartsWith($expected, $decoded);
+        }
     }
 
     public function testEmptyString()