Enable PDFDocEncoding support for metadata #611
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Regular PDF metadata (outside of XMP), depending on the characters it includes, can be encoded in UTF-8 escaped (or binary) bytes, or using a proprietary Adobe encoding PDFDocEncoding which is similar to, but not exactly like CP1252. For more information on the PDFDocEncoding character set, see: https://ia801001.us.archive.org/1/items/pdf1.7/pdf_reference_1-7.pdf Another issue is that regardless of the storage encoding used, Adobe Acrobat will attempt to add a slash-linefeed (\r) to metadata text to avoid long line-lengths (~127 bytes) in the saved PDF data. Unfortunately, the method to do this does not seem binary-safe, resulting in UTF-8 saved bytes that are destroyed and must be repaired. This commit enables decoding PDF metadata using PDFDocEncoding, and also repairs added line-feeds in both PDFDocEncoding and UTF-8. It also adds a sample file "Issue609.pdf" containing both UTF-8 and PDFDocEncoding encoded metadata fields for testing. The name of the file references PDFParser issue smalot#609: smalot#609
I hope I am not assuming too much by adding myself as the author of this file!
This was referenced Jul 6, 2023
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Jul 6, 2023
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@GreyWyvern Thank you again for taking the time improving this library.
I have a few remarks, but nothing big.
Add comments in Document.php Use plain class PDFDocEncoding, do not extend AbstractEncoding array() => [] Break up class functions into one that returns the code table, and another that uses the table to perform the conversion
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Regular PDF metadata (outside of XMP), depending on the characters it includes, can be encoded in UTF-8 escaped (or binary) bytes, or using a proprietary Adobe encoding PDFDocEncoding which is similar to, but not exactly like CP1252 (WinAnsiEncoding).
For more information on the PDFDocEncoding character set, see: https://ia801001.us.archive.org/1/items/pdf1.7/pdf_reference_1-7.pdf
Another issue is that regardless of the storage encoding used, Adobe Acrobat will attempt to add a slash-linefeed (\r) to metadata text to avoid long line-lengths (~127 bytes) in the saved PDF data. Unfortunately, the method to do this does not seem binary-safe, resulting in UTF-8 saved bytes that are damaged and must be repaired.
This commit enables decoding PDF metadata using PDFDocEncoding, and also repairs added line-feeds in both PDFDocEncoding and UTF-8.
It also adds a sample file "Issue609.pdf" containing both UTF-8 and PDFDocEncoding encoded metadata fields for testing. The name of the file references PDFParser issue #609
Edit: My apologies for the failing tests. I don't think I'm running PHPStan properly since I'm using the phar instead of composer. My env doesn't have direct/full access to the internet, so I can't really use composer.