Panic with index out of range on some PDF files

[jojomi]

For several files I have seen this when using this library:

panic: runtime error: index out of range [0] with length 0

goroutine 1 [running]:
github.com/flotzilla/pdf_parser.getPreTrailerData(0xc00039b860, 0xc8, 0xc8, 0xc8, 0xc8, 0x1, 0x0, 0x0, 0x0)
        github.com/flotzilla/pdf_parser@v0.1.96/parser.go:737 +0xfd
github.com/flotzilla/pdf_parser.readXrefBlock(0xc000010118, 0x20d74, 0x1, 0x0, 0xc0000101f8, 0xc8, 0x1)
        github.com/flotzilla/pdf_parser@v0.1.96/parser.go:552 +0x67f
github.com/flotzilla/pdf_parser.readAllXrefSections(0xc000010118, 0xc000340340, 0x20d74)
        github.com/flotzilla/pdf_parser@v0.1.96/parser.go:455 +0x50

Unfortunately I can share none of the files I checked. Perhaps you can still see why this might happen?

[nacimgoura]

Same error

[gekkowrld]

Fixed (or at least prevented the panic) -> https://github.com/gekkowrld/pdf_parser