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fix parsing tables missing a line break

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This commit is contained in:
EliotJones 2025-08-03 14:45:41 -05:00
parent 4409998de9
commit 48b3c26b53
2 changed files with 27 additions and 22 deletions
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1
src/UglyToad.PdfPig/Parser/FileStructure/XrefStreamParser.cs
View File

@ -62,7 +62,6 @@ internal static class XrefStreamParser
try
{
var streamData = ReadStreamTolerant(bytes);
if (!streamData.to.HasValue)

48
src/UglyToad.PdfPig/Parser/FileStructure/XrefTableParser.cs
View File

@ -26,8 +26,7 @@ internal static class XrefTableParser
var correctionType = XrefOffsetCorrection.None;
var correction = 0L;
if (!scanner.TryReadToken(out OperatorToken xrefOp)
|| !string.Equals("xref", xrefOp.Data, StringComparison.OrdinalIgnoreCase))
if (!TryReadXrefToken(scanner))
{
log.Debug($"Xref not found at {xrefOffset}, trying to recover");
var recovered = TryRecoverOffset(fileHeaderOffset, xrefOffset, bytes, scanner);
@ -38,7 +37,7 @@ internal static class XrefTableParser
log.Debug($"Xref found at {recovered.Value.correctOffset}");
scanner.Seek(recovered.Value.correctOffset);
if (!scanner.TryReadToken(out xrefOp))
if (!TryReadXrefToken(scanner))
{
return null;
}
@ -48,20 +47,6 @@ internal static class XrefTableParser
xrefOffset = recovered.Value.correctOffset;
}
if (!string.Equals("xref", xrefOp.Data, StringComparison.OrdinalIgnoreCase))
{
// Support xref not being followed by spaces or newlines, e.g. "xref5 0"
if (xrefOp.Data.StartsWith("xref", StringComparison.OrdinalIgnoreCase))
{
var backtrack = xrefOp.Data.Length - "xref".Length;
scanner.Seek(scanner.CurrentPosition - backtrack);
}
else
{
return null;
}
}
const int objRowSentinel = -1;
const int freeSentinel = 0;
const int occupiedSentinel = 1;
@ -258,6 +243,29 @@ internal static class XrefTableParser
return new XrefTable(xrefOffset, offsets, trailer, correctionType, correction);
}
private static bool TryReadXrefToken(ISeekableTokenScanner scanner)
{
if (!scanner.TryReadToken(out OperatorToken xrefOp))
{
return false;
}
if (string.Equals("xref", xrefOp.Data, StringComparison.OrdinalIgnoreCase))
{
return true;
}
// Support xref not being followed by spaces or newlines, e.g. "xref5 0"
if (xrefOp.Data.StartsWith("xref", StringComparison.OrdinalIgnoreCase))
{
var backtrack = xrefOp.Data.Length - "xref".Length;
scanner.Seek(scanner.CurrentPosition - backtrack);
return true;
}
return false;
}
/// <summary>
/// The provided offset can frequently be close but not quite correct.
/// The 2 most common failure modes are that the PDF content starts at some
@ -274,8 +282,7 @@ internal static class XrefTableParser
if (fileHeaderOffset.Value > 0)
{
scanner.Seek(xrefOffset + fileHeaderOffset.Value);
if (scanner.TryReadToken(out OperatorToken xrefOp)
&& xrefOp.Data.Equals("xref", StringComparison.OrdinalIgnoreCase))
if (TryReadXrefToken(scanner))
{
return (xrefOffset + fileHeaderOffset.Value, XrefOffsetCorrection.FileHeaderOffset);
}
@ -303,8 +310,7 @@ internal static class XrefTableParser
var actualOffset = offset + xrefIx;
scanner.Seek(actualOffset);
if (scanner.TryReadToken(out OperatorToken ot)
&& string.Equals(ot.Data, "xref", StringComparison.OrdinalIgnoreCase))
if (TryReadXrefToken(scanner))
{
return (actualOffset, XrefOffsetCorrection.Random);
}