Skip trailing null bytes when searching for EOF marker#586
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Skip trailing null bytes when searching for EOF marker#586
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Some PDF generators (e.g. Atos/Fonet) append thousands of null bytes after %%EOF. Since null bytes are not line terminators, they prevented the EOF marker from being found within the trailing byte scan window. This change scans backwards from the end of the file to skip any trailing null bytes before reading the final bytes to locate the %%EOF marker and xref offset. Fixes yob#585
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Problem
PDFs generated by some tools (e.g. Atos/Fonet) append thousands of null bytes (
\x00) after%%EOF. Since null bytes are not line terminators, they are not split by the line parser, preventing the EOF marker from being found within the trailing byte scan window (TRAILING_BYTECOUNT = 5000).This causes
PDF::Reader::MalformedPDFError: PDF does not contain EOF marker.Solution
Scan backwards from the end of the file to skip any trailing null bytes before reading the final bytes to locate the
%%EOFmarker and xref offset. This handles any amount of trailing null bytes regardless ofTRAILING_BYTECOUNT.The existing
NULL_BYTEconstant defined inBufferis reused.Test
Added
trailing_null_bytes.pdf(extended_eof.pdf + 6000 null bytes) and a spec that verifies the correct xref offset (145) is still found.Fixes #585