New C module for quopri assist

[8e121080-cc2d-4f2f-9b30-7e4536124e42]

BPO	462190
Nosy	@gvanrossum, @loewis
Files	quoted.patch: Patch against recent python 2.2 CVS binascii.patch: Patch against recent python 2.2 CVS binascii.patch2 binascii.patch4: Patch against recent python 2.2 CVS

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GitHub fields: ```python assignee = 'https://github.com/loewis' closed_at = created_at = labels = ['extension-modules'] title = 'New C module for quopri assist' updated_at = user = 'https://bugs.python.org/blong42' ``` bugs.python.org fields: ```python activity = actor = 'loewis' assignee = 'loewis' closed = True closed_date = None closer = None components = ['Extension Modules'] creation = creator = 'blong42' dependencies = [] files = ['3614', '3615', '3616', '3617'] hgrepos = [] issue_num = 462190 keywords = ['patch'] message_count = 9.0 messages = ['37605', '37606', '37607', '37608', '37609', '37610', '37611', '37612', '37613'] nosy_count = 3.0 nosy_names = ['gvanrossum', 'loewis', 'blong42'] pr_nums = [] priority = 'normal' resolution = 'accepted' stage = None status = 'closed' superseder = None type = None url = 'https://bugs.python.org/issue462190' versions = [] ```

[8e121080-cc2d-4f2f-9b30-7e4536124e42]

This patch adds a new module, quoted, and code in quopri to use this module if it exists. This module implements quoted printable encoding and decoding based on strings in C. This was required by a recent project of mine because 1MB quoted printable mail attachments (sometimes chosen to send PDF and PS data) would take 40+ minutes to encode and decode using the standard quopri python module.

[gvanrossum]

Logged In: YES user_id=6380

It would make more sense to add this as another pair of encodings to the binascii module, which provides similar support for binhex, base64, and uuencode.

[8e121080-cc2d-4f2f-9b30-7e4536124e42]

Logged In: YES user_id=325633

Ok, this new patch adds the code to binascii, b2a_qp and a2b_qp.

[61337411-43fc-4a9c-b8d5-4060aede66d0]

Logged In: YES user_id=21627

The patch looks good to me. A couple of comments that may be worth consideration:

• if backwards compatibility is an objective, boundary cases should be analysed in more detail. E.g. it appears that the case of invalid escape sequences (=EI) is handled differently.
• the new module, when encoding one file into anothher, reads all data, whereas the old one would read line by line. Is that change desirable?
• the C code could avoid copying the string if it allocated a PyString right away, and adjusted it with _Resize when it is done.

[8e121080-cc2d-4f2f-9b30-7e4536124e42]

Logged In: YES user_id=325633

Ok, this version handles invalid escape sequences the same way, ie by leaving them as they were in the input stream.

My original reason for writing this was performance, and the size of the input was already restricted to 1MB, hence the chosen in memory encode/decode. No one is likely to be using the current version for anything even approaching that size given the abysmal performance of the current version. Given that 2.2 adds the decodestring and encodestring versions, maybe we should have both, I'm not sure. The new mimelib module handles mail in memory, instead of using the file like operations of the rfc822 module. *shrug*

Using PyString in that fashion I don't think will save anything... as the only external interfaces for that would do a copy on create with PyString_FromStringAndSize(), and then a realloc with the PyString_Resize() (though I could be missing something in there).

[61337411-43fc-4a9c-b8d5-4060aede66d0]

Logged In: YES user_id=21627

I get numerous failures when running test_quopri. Do you see the same problems? Can you correct them?

[61337411-43fc-4a9c-b8d5-4060aede66d0]

Logged In: YES user_id=21627

Please have a look at the patch in

http://sourceforge.net/tracker/index.php?func=detail&aid=464070&group_id=5470&atid=305470

and the bug 463966. Would you be interested in fixing those bugs as well, and integrating the fixes into your C code?

[8e121080-cc2d-4f2f-9b30-7e4536124e42]

Logged In: YES user_id=325633

Ok, this version (4) of the patch fixes the bugs introduced in version (2), and also incorporates the patch from 464070, which fixes bug 463966 in both C and the quopri code. This version also includes an optional argument that will cause header encoding in the encoding functions, as well as documentation of the new functions in the binascii module.

[61337411-43fc-4a9c-b8d5-4060aede66d0]

Logged In: YES user_id=21627

Thanks again for the patch. It was committed as libbinascii.tex 1.21, libquopri.tex 1.14, quopri.py 1.16, test_quopri.py 1.6, NEWS 1.261, binascii.c 2.30.