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Groups > comp.lang.python > #49132
| From | Christian Gollwitzer <auriocus@gmx.de> |
|---|---|
| Newsgroups | comp.lang.python |
| Subject | Re: io module and pdf question |
| Date | 2013-06-25 09:18 +0200 |
| Organization | A noiseless patient Spider |
| Message-ID | <kqbfuh$nbs$1@dont-email.me> (permalink) |
| References | <mailman.3795.1372133932.3114.python-list@python.org> <959e769b-fdfb-49bb-9a61-7056d01a03d4@googlegroups.com> |
Am 25.06.13 08:33, schrieb rusi: > On Tuesday, June 25, 2013 9:48:44 AM UTC+5:30, jyou...@kc.rr.com > wrote: >> 1. Is there another way to get metadata out of a pdf without having >> to install another module? 2. Is it safe to assume pdf files should >> always be encoded as latin-1 (when trying to read it this way)? Is >> there a chance they could be something else? > > If your code is binary open in binary mode (mode="rb") rather than > choosing a bogus encoding. You then have to make your strings also > binary (b-prefix) Also I am surprised that it works at all. Most > pdfs are compressed I thought?? > PDFs are a binary format, yes. But they are not, as a whole, compressed. They are made up of "objects", which can be referred to and crosslinked, and these objects are represented as ASCII strings. Some of these can specify a "decoding filter". Examples for the filter include zlib compression (/FlateDecode) and jpeg compression (/DCTDecode). Most of the PDF objects are therefore not encoded. It is, however, possible to include a PDF into another PDF and to encode it, but that's a rare case. Therefore the metadata can usually be read in text mode. However, to correctly find all objects, the xref-table indexes offsets into the PDF. It must be treated binary in any case, and that's the funny reason for the first 3 characters of the PDF - they must include characters with the 8th bit set, such that FTP applications treat it as binary. Christian
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io module and pdf question <jyoung79@kc.rr.com> - 2013-06-25 04:18 +0000
Re: io module and pdf question rusi <rustompmody@gmail.com> - 2013-06-24 23:33 -0700
Re: io module and pdf question Christian Gollwitzer <auriocus@gmx.de> - 2013-06-25 09:18 +0200
Re: io module and pdf question wxjmfauth@gmail.com - 2013-06-26 07:11 -0700
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