Skip to content

gh-137855: email.quoprimime removing re import #132046

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 11 commits into from
Closed

gh-137855: email.quoprimime removing re import #132046

Changes from all commits
Commits
Show all changes
11 commits
Select commit Hold shift + click to select a range
c670b11
Removed re hex
Marius-Juston Apr 3, 2025
08cdc0b
implace replace, removed valid_hex parameter
Marius-Juston Apr 3, 2025
a3ef550
joined to big if statement
Marius-Juston Apr 3, 2025
22e6d9e
added news
Marius-Juston Apr 3, 2025
232bb55
inline character assigment
Marius-Juston Apr 3, 2025
3ada67a
use cache for hex to char + instead of single character append use sl…
Marius-Juston Apr 3, 2025
9e3cc1f
inplace assignment with walrus
Marius-Juston Apr 3, 2025
3287564
removed news since should probably be "skip news" tagged
Marius-Juston Apr 3, 2025
8362a2e
fast pass for no '='
Marius-Juston Apr 3, 2025
81ae23a
Update Lib/email/quoprimime.py
Marius-Juston Apr 4, 2025
8659486
faster string concatenation
Marius-Juston Apr 4, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
37 changes: 27 additions & 10 deletions Lib/email/quoprimime.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,6 @@
'unquote',
]

import re

from string import ascii_letters, digits, hexdigits

CRLF = '\r\n'
Expand Down Expand Up @@ -281,12 +279,7 @@ def decode(encoded, eol=NL):
decodestring = decode



def _unquote_match(match):
"""Turn a match in the form =AB to the ASCII character with value 0xab"""
s = match.group(0)
return unquote(s)

_HEX_TO_CHAR = {f'{i:02x}': chr(i) for i in range(256)}

# Header decoding is done a bit differently
def header_decode(s):
Expand All @@ -296,5 +289,29 @@ def header_decode(s):
quoted-printable (like =?iso-8859-1?q?Hello_World?=) -- please use
the high level email.header class for that functionality.
"""
s = s.replace('_', ' ')
return re.sub(r'=[a-fA-F0-9]{2}', _unquote_match, s, flags=re.ASCII)
# Check for regex =[a-fA-F0-9]{2}
s = s.replace("_", " ")

if '=' not in s:
return s

result = ''
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Repeatedly appending to a string in a loop is O(n**2). The standard idiom is to make a list of pieces (result=[]) and join after the loop. I suspect that re.sub does the C equivalent.

In any case, I agree that replacing an re call with this much code seems dubious (a bad tradeoff), so closing this might be best.

s_len = len(s)
i = 0
last_append = 0

while i < s_len:
if s[i] == '=' and i + 2 < s_len:
if (hex_str := s[i + 1:i + 3].lower()) in _HEX_TO_CHAR:
if last_append < i:
result += s[last_append:i]
result += _HEX_TO_CHAR[hex_str]
i += 3
last_append = i
continue
i += 1

if last_append < s_len:
result += s[last_append:]

return result
Loading