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Merged
PrinsFrank merged 1 commit into from
Jun 15, 2026
Merged

Recover byte offsets from raw stream when cross reference source is corrupt #413

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12 changes: 11 additions & 1 deletion src/Document/CrossReference/CrossReferenceSourceParser.php
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,9 @@

namespace PrinsFrank\PdfParser\Document\CrossReference;

use PrinsFrank\PdfParser\Document\CrossReference\RawStream\ObjectPositionsFromRawStreamParser;
use PrinsFrank\PdfParser\Document\CrossReference\Source\CrossReferenceSource;
use PrinsFrank\PdfParser\Document\CrossReference\Source\RecoveredCrossReferenceSource;
use PrinsFrank\PdfParser\Document\CrossReference\Stream\CrossReferenceStreamParser;
use PrinsFrank\PdfParser\Document\CrossReference\Table\CrossReferenceTableParser;
use PrinsFrank\PdfParser\Document\Dictionary\DictionaryKey\DictionaryKey;
Expand Down Expand Up @@ -80,7 +82,15 @@ public static function parse(Stream $stream): CrossReferenceSource {
$crossReferenceSections[] = $currentCrossReferenceSection;
}

return new CrossReferenceSource(... $crossReferenceSections);
$crossReferenceSource = new CrossReferenceSource(... $crossReferenceSections);
if ($crossReferenceSource->hasInvalidByteOffset($stream)) {
return new RecoveredCrossReferenceSource(
ObjectPositionsFromRawStreamParser::parse($stream),
...$crossReferenceSections,
);
}

return $crossReferenceSource;
}

private static function getCrossReferenceType(Stream $stream, int $byteOffsetLastCrossReferenceSection, int $byteOffsetEndOfCurrentLine): ?CrossReferenceType {
Expand Down
67 changes: 67 additions & 0 deletions src/Document/CrossReference/RawStream/ObjectPositionsFromRawStreamParser.php
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@@ -0,0 +1,67 @@
<?php declare(strict_types=1);

namespace PrinsFrank\PdfParser\Document\CrossReference\RawStream;

use PrinsFrank\PdfParser\Stream\Stream;

class ObjectPositionsFromRawStreamParser {
/** @return array<int, int> */
public static function parse(Stream $stream): array {
$inObjNr = $inObjGenerationNumber = $pendingObjMarker = false;
$startObjNrOffset = $objNrBuffer = $objMarkerBuffer = null;
$discoveredObjects = [];
foreach ($stream->chars(0, $stream->getSizeInBytes()) as $byteOffset => $char) {
if ($char === ' ') {
if ($inObjNr === true) {
$inObjNr = false;
$inObjGenerationNumber = true;
} elseif ($inObjGenerationNumber === true) {
$inObjGenerationNumber = false;
$pendingObjMarker = true;
} else {
$inObjNr = $inObjGenerationNumber = $pendingObjMarker = false;
$startObjNrOffset = $objNrBuffer = $objMarkerBuffer = null;
}
} elseif ($char === '0'
|| $char === '1'
|| $char === '2'
|| $char === '3'
|| $char === '4'
|| $char === '5'
|| $char === '6'
|| $char === '7'
|| $char === '8'
|| $char === '9') {
if ($pendingObjMarker === true) {
$pendingObjMarker = false;
$objNrBuffer = null;
} elseif ($inObjGenerationNumber === true) {
} elseif ($inObjNr === false) {
$inObjNr = true;
$startObjNrOffset = $byteOffset;
$objNrBuffer = $char;
} elseif ($inObjNr === true) {
$objNrBuffer .= $char;
}
} elseif ($pendingObjMarker === true) {
if ($objMarkerBuffer === null && $char === 'o') { // @phpstan-ignore identical.alwaysTrue
$objMarkerBuffer = $char;
} elseif ($objMarkerBuffer === 'o' && $char === 'b') { // @phpstan-ignore identical.alwaysFalse, booleanAnd.alwaysFalse
$objMarkerBuffer .= $char;
} elseif ($objMarkerBuffer === 'ob' && $char === 'j') { // @phpstan-ignore identical.alwaysFalse, booleanAnd.alwaysFalse
$discoveredObjects[(int) $objNrBuffer] = $startObjNrOffset;
$inObjNr = $inObjGenerationNumber = $pendingObjMarker = false;
$startObjNrOffset = $objNrBuffer = $objMarkerBuffer = null;
} else {
$inObjNr = $inObjGenerationNumber = $pendingObjMarker = false;
$startObjNrOffset = $objNrBuffer = $objMarkerBuffer = null;
}
} else {
$inObjNr = $inObjGenerationNumber = $pendingObjMarker = false;
$startObjNrOffset = $objNrBuffer = $objMarkerBuffer = null;
}
}

return $discoveredObjects;
}
}
14 changes: 13 additions & 1 deletion src/Document/CrossReference/Source/CrossReferenceSource.php
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Expand Up @@ -12,7 +12,9 @@
use PrinsFrank\PdfParser\Document\Dictionary\DictionaryValue\DictionaryValue;
use PrinsFrank\PdfParser\Document\Dictionary\DictionaryValue\Name\NameValue;
use PrinsFrank\PdfParser\Document\Dictionary\DictionaryValue\Reference\ReferenceValue;
use PrinsFrank\PdfParser\Document\Document;
use PrinsFrank\PdfParser\Exception\ParseFailureException;
use PrinsFrank\PdfParser\Stream\Stream;

/** Can be both from a crossReferenceTable or a crossReferenceStream */
class CrossReferenceSource {
Expand All @@ -26,7 +28,7 @@ public function __construct(
$this->crossReferenceSections = $crossReferenceSections;
}

public function getCrossReferenceEntry(int $objNumber): CrossReferenceEntryInUseObject|CrossReferenceEntryCompressed|null {
public function getCrossReferenceEntry(int $objNumber, Document $document): CrossReferenceEntryInUseObject|CrossReferenceEntryCompressed|null {
foreach ($this->crossReferenceSections as $crossReferenceSection) {
$crossReferenceEntry = $crossReferenceSection->getCrossReferenceEntry($objNumber);
if ($crossReferenceEntry !== null) {
Expand Down Expand Up @@ -75,4 +77,14 @@ public function getFirstId(): string {

return $firstId;
}

public function hasInvalidByteOffset(Stream $stream): bool {
foreach ($this->crossReferenceSections as $crossReferenceSection) {
if ($crossReferenceSection->hasInvalidByteOffset($stream)) {
return true;
}
}

return false;
}
}
38 changes: 38 additions & 0 deletions src/Document/CrossReference/Source/RecoveredCrossReferenceSource.php
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@@ -0,0 +1,38 @@
<?php declare(strict_types=1);

namespace PrinsFrank\PdfParser\Document\CrossReference\Source;

use Override;
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\CrossReferenceSection;
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\SubSection\Entry\CrossReferenceEntryCompressed;
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\SubSection\Entry\CrossReferenceEntryInUseObject;
use PrinsFrank\PdfParser\Document\Document;

class RecoveredCrossReferenceSource extends CrossReferenceSource {
/**
* @param array<int, int> $recoveredByteOffsetMap where the key is the object nr and the value the byte offset
*
* @no-named-arguments
*/
public function __construct(
private readonly array $recoveredByteOffsetMap,
CrossReferenceSection... $crossReferenceSections,
) {
parent::__construct(...$crossReferenceSections);
}

#[Override]
public function getCrossReferenceEntry(int $objNumber, Document $document): CrossReferenceEntryInUseObject|CrossReferenceEntryCompressed|null {
$crossReferenceEntry = parent::getCrossReferenceEntry($objNumber, $document);
if ($crossReferenceEntry instanceof CrossReferenceEntryInUseObject
&& $document->stream->read($crossReferenceEntry->byteOffsetInDecodedStream, strlen($expectedStartObjMarker = sprintf('%d %d obj', $objNumber, $crossReferenceEntry->generationNumber))) === $expectedStartObjMarker) {
return $crossReferenceEntry;
}

if (array_key_exists($objNumber, $this->recoveredByteOffsetMap)) {
return new CrossReferenceEntryInUseObject($this->recoveredByteOffsetMap[$objNumber], 0);
}

return $crossReferenceEntry;
}
}
11 changes: 11 additions & 0 deletions src/Document/CrossReference/Source/Section/CrossReferenceSection.php
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Expand Up @@ -6,6 +6,7 @@
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\SubSection\Entry\CrossReferenceEntryCompressed;
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\SubSection\Entry\CrossReferenceEntryInUseObject;
use PrinsFrank\PdfParser\Document\Dictionary\Dictionary;
use PrinsFrank\PdfParser\Stream\Stream;

/** There are multiple crossReference sections if there are incremental updates. See 7.5.6 */
readonly class CrossReferenceSection {
Expand All @@ -29,4 +30,14 @@ public function getCrossReferenceEntry(int $objNumber): CrossReferenceEntryInUse

return null;
}

public function hasInvalidByteOffset(Stream $stream): bool {
foreach ($this->crossReferenceSubSections as $crossReferenceSubSection) {
if ($crossReferenceSubSection->hasInvalidByteOffset($stream)) {
return true;
}
}

return false;
}
}
21 changes: 21 additions & 0 deletions src/Document/CrossReference/Source/Section/SubSection/CrossReferenceSubSection.php
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Expand Up @@ -8,6 +8,7 @@
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\SubSection\Entry\CrossReferenceEntryInUseObject;
use PrinsFrank\PdfParser\Exception\InvalidArgumentException;
use PrinsFrank\PdfParser\Exception\RuntimeException;
use PrinsFrank\PdfParser\Stream\Stream;

readonly class CrossReferenceSubSection {
/** @var array<CrossReferenceEntryInUseObject|CrossReferenceEntryFreeObject|CrossReferenceEntryCompressed> */
Expand Down Expand Up @@ -51,4 +52,24 @@ public function getCrossReferenceEntry(int $objNumber): CrossReferenceEntryInUse

return $object;
}

public function hasInvalidByteOffset(Stream $stream): bool {
foreach ($this->crossReferenceEntries as $index => $crossReferenceEntry) {
if ($crossReferenceEntry instanceof CrossReferenceEntryInUseObject === false) {
continue;
}

if ($crossReferenceEntry->byteOffsetInDecodedStream > $stream->getSizeInBytes()) {
return true;
}

$objNumber = $this->firstObjectNumber + $index;
$expectedObjMarker = $objNumber . ' ' . $crossReferenceEntry->generationNumber . ' obj';
if ($stream->read($crossReferenceEntry->byteOffsetInDecodedStream, strlen($expectedObjMarker)) !== $expectedObjMarker) {
return true;
}
}

return false;
}
}
2 changes: 1 addition & 1 deletion src/Document/Document.php
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Expand Up @@ -128,7 +128,7 @@ public function getObject(int $objectNumber, ?string $expectedDecoratorFQN = nul
return $this->objectCache[$objectNumber];
}

$crossReferenceEntry = $this->crossReferenceSource->getCrossReferenceEntry($objectNumber);
$crossReferenceEntry = $this->crossReferenceSource->getCrossReferenceEntry($objectNumber, $this);
if ($crossReferenceEntry === null) {
return null;
}
Expand Down
21 changes: 17 additions & 4 deletions tests/Feature/H7Stage1UpdatingTest.php
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Expand Up @@ -4,7 +4,7 @@

use PHPUnit\Framework\Attributes\CoversNothing;
use PHPUnit\Framework\TestCase;
use PrinsFrank\PdfParser\Document\CrossReference\Source\CrossReferenceSource;
use PrinsFrank\PdfParser\Document\CrossReference\Source\RecoveredCrossReferenceSource;
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\CrossReferenceSection;
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\SubSection\CrossReferenceSubSection;
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\SubSection\Entry\CrossReferenceEntryFreeObject;
Expand Down Expand Up @@ -36,7 +36,20 @@ public function testStructure(): void {

static::assertSame(Version::V1_4, $document->version);
static::assertEquals(
new CrossReferenceSource(
new RecoveredCrossReferenceSource(
[
1 => 9,
2 => 74,
3 => 120,
4 => 604,
5 => 704,
6 => 788,
7 => 812,
8 => 856,
9 => 958,
10 => 1062,
11 => 1166,
],
new CrossReferenceSection(
new Dictionary(
new DictionaryEntry(DictionaryKey::SIZE, new IntegerValue(12)),
Expand Down Expand Up @@ -217,7 +230,7 @@ public function testStructure(): void {
$document,
7,
0,
811,
812,
855,
),
$document,
Expand Down Expand Up @@ -307,7 +320,7 @@ public function testStructure(): void {
$document,
11,
0,
1165,
1166,
1269,
),
$document,
Expand Down
5 changes: 3 additions & 2 deletions tests/Unit/Document/CrossReference/CrossReferenceSourceParserTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@
use PHPUnit\Framework\Attributes\CoversClass;
use PHPUnit\Framework\TestCase;
use PrinsFrank\PdfParser\Document\CrossReference\CrossReferenceSourceParser;
use PrinsFrank\PdfParser\Document\CrossReference\Source\CrossReferenceSource;
use PrinsFrank\PdfParser\Document\CrossReference\Source\RecoveredCrossReferenceSource;
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\CrossReferenceSection;
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\SubSection\CrossReferenceSubSection;
use PrinsFrank\PdfParser\Document\CrossReference\Source\Section\SubSection\Entry\CrossReferenceEntryFreeObject;
Expand All @@ -21,7 +21,8 @@
class CrossReferenceSourceParserTest extends TestCase {
public function testParse(): void {
static::assertEquals(
new CrossReferenceSource(
new RecoveredCrossReferenceSource(
[],
new CrossReferenceSection(
new Dictionary(
new DictionaryEntry(DictionaryKey::SIZE, new IntegerValue(7)),
Expand Down
34 changes: 34 additions & 0 deletions tests/Unit/Document/CrossReference/RawStream/ObjectPositionsFromRawStreamParserTest.php
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@@ -0,0 +1,34 @@
<?php declare(strict_types=1);

namespace PrinsFrank\PdfParser\Tests\Unit\Document\CrossReference\RawStream;

use PHPUnit\Framework\Attributes\CoversClass;
use PHPUnit\Framework\TestCase;
use PrinsFrank\PdfParser\Document\CrossReference\RawStream\ObjectPositionsFromRawStreamParser;
use PrinsFrank\PdfParser\Stream\InMemoryStream;

#[CoversClass(ObjectPositionsFromRawStreamParser::class)]
class ObjectPositionsFromRawStreamParserTest extends TestCase {
public function testParse(): void {
static::assertSame(
[
1 => 10,
1232131 => 42,
],
ObjectPositionsFromRawStreamParser::parse(
new InMemoryStream(
<<<PDF
%%PDF-1.7
1 0 obj
4 0 4 0 testobj
endobj

1232131 0 obj
endobj

PDF,
),
),
);
}
}
7 changes: 4 additions & 3 deletions tests/Unit/Document/CrossReference/Source/CrossReferenceSourceTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@
use PrinsFrank\PdfParser\Document\Dictionary\DictionaryEntry\DictionaryEntry;
use PrinsFrank\PdfParser\Document\Dictionary\DictionaryKey\DictionaryKey;
use PrinsFrank\PdfParser\Document\Dictionary\DictionaryValue\Reference\ReferenceValue;
use PrinsFrank\PdfParser\Document\Document;

#[CoversClass(CrossReferenceSource::class)]
class CrossReferenceSourceTest extends TestCase {
Expand All @@ -34,9 +35,9 @@ public function testGetCrossReferenceEntry(): void {
),
),
);
static::assertSame($crossReferenceEntry1, $crossReferenceSource->getCrossReferenceEntry(42));
static::assertSame($crossReferenceEntry2, $crossReferenceSource->getCrossReferenceEntry(43));
static::assertNull($crossReferenceSource->getCrossReferenceEntry(44));
static::assertSame($crossReferenceEntry1, $crossReferenceSource->getCrossReferenceEntry(42, $this->createMock(Document::class)));
static::assertSame($crossReferenceEntry2, $crossReferenceSource->getCrossReferenceEntry(43, $this->createMock(Document::class)));
static::assertNull($crossReferenceSource->getCrossReferenceEntry(44, $this->createMock(Document::class)));
}

public function testGetReferenceForKey(): void {
Expand Down
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