cpython/Lib/sre_parse.py

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#
# Secret Labs' Regular Expression Engine
#
# convert re-style regular expression to sre pattern
#
# Copyright (c) 1998-2001 by Secret Labs AB. All rights reserved.
#
# See the sre.py file for information on usage and redistribution.
#
"""Internal support module for sre"""
# XXX: show string offset and offending character for all errors
import sys
from sre_constants import *
def set(seq):
s = {}
for elem in seq:
s[elem] = 1
return s
SPECIAL_CHARS = ".\\[{()*+?^$|"
REPEAT_CHARS = "*+?{"
DIGITS = set("0123456789")
OCTDIGITS = set("01234567")
HEXDIGITS = set("0123456789abcdefABCDEF")
WHITESPACE = set(" \t\n\r\v\f")
ESCAPES = {
r"\a": (LITERAL, ord("\a")),
r"\b": (LITERAL, ord("\b")),
r"\f": (LITERAL, ord("\f")),
r"\n": (LITERAL, ord("\n")),
r"\r": (LITERAL, ord("\r")),
r"\t": (LITERAL, ord("\t")),
r"\v": (LITERAL, ord("\v")),
r"\\": (LITERAL, ord("\\"))
}
CATEGORIES = {
r"\A": (AT, AT_BEGINNING_STRING), # start of string
r"\b": (AT, AT_BOUNDARY),
r"\B": (AT, AT_NON_BOUNDARY),
r"\d": (IN, [(CATEGORY, CATEGORY_DIGIT)]),
r"\D": (IN, [(CATEGORY, CATEGORY_NOT_DIGIT)]),
r"\s": (IN, [(CATEGORY, CATEGORY_SPACE)]),
r"\S": (IN, [(CATEGORY, CATEGORY_NOT_SPACE)]),
r"\w": (IN, [(CATEGORY, CATEGORY_WORD)]),
r"\W": (IN, [(CATEGORY, CATEGORY_NOT_WORD)]),
r"\Z": (AT, AT_END_STRING), # end of string
}
FLAGS = {
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# standard flags
"i": SRE_FLAG_IGNORECASE,
"L": SRE_FLAG_LOCALE,
"m": SRE_FLAG_MULTILINE,
"s": SRE_FLAG_DOTALL,
"x": SRE_FLAG_VERBOSE,
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# extensions
"a": SRE_FLAG_ASCII,
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"t": SRE_FLAG_TEMPLATE,
"u": SRE_FLAG_UNICODE,
}
class Pattern:
# master pattern object. keeps track of global attributes
def __init__(self):
self.flags = 0
self.open = []
self.groups = 1
self.groupdict = {}
def opengroup(self, name=None):
gid = self.groups
self.groups = gid + 1
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if name is not None:
ogid = self.groupdict.get(name, None)
if ogid is not None:
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raise error("redefinition of group name %s as group %d; "
"was group %d" % (repr(name), gid, ogid))
self.groupdict[name] = gid
self.open.append(gid)
return gid
def closegroup(self, gid):
self.open.remove(gid)
def checkgroup(self, gid):
return gid < self.groups and gid not in self.open
class SubPattern:
# a subpattern, in intermediate form
def __init__(self, pattern, data=None):
self.pattern = pattern
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if data is None:
data = []
self.data = data
self.width = None
def dump(self, level=0):
nl = 1
seqtypes = (tuple, list)
for op, av in self.data:
print(level*" " + op, end=' '); nl = 0
if op == "in":
# member sublanguage
print(); nl = 1
for op, a in av:
print((level+1)*" " + op, a)
elif op == "branch":
print(); nl = 1
i = 0
for a in av[1]:
if i > 0:
print(level*" " + "or")
a.dump(level+1); nl = 1
i = i + 1
elif isinstance(av, seqtypes):
for a in av:
if isinstance(a, SubPattern):
if not nl: print()
a.dump(level+1); nl = 1
else:
print(a, end=' ') ; nl = 0
else:
print(av, end=' ') ; nl = 0
if not nl: print()
def __repr__(self):
return repr(self.data)
def __len__(self):
return len(self.data)
def __delitem__(self, index):
del self.data[index]
def __getitem__(self, index):
Merged revisions 53005-53303 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r53012 | walter.doerwald | 2006-12-12 22:55:31 +0100 (Tue, 12 Dec 2006) | 2 lines Fix typo. ........ r53023 | brett.cannon | 2006-12-13 23:31:37 +0100 (Wed, 13 Dec 2006) | 2 lines Remove an unneeded import of 'warnings'. ........ r53025 | brett.cannon | 2006-12-14 00:02:38 +0100 (Thu, 14 Dec 2006) | 2 lines Remove unneeded imports of 'warnings'. ........ r53026 | brett.cannon | 2006-12-14 00:09:53 +0100 (Thu, 14 Dec 2006) | 4 lines Add test.test_support.guard_warnings_filter . This function returns a context manager that protects warnings.filter from being modified once the context is exited. ........ r53029 | george.yoshida | 2006-12-14 03:22:44 +0100 (Thu, 14 Dec 2006) | 2 lines Note that guard_warnings_filter was added in 2.6 ........ r53031 | vinay.sajip | 2006-12-14 09:53:55 +0100 (Thu, 14 Dec 2006) | 1 line Added news on recent changes to logging ........ r53032 | andrew.kuchling | 2006-12-14 19:57:53 +0100 (Thu, 14 Dec 2006) | 1 line [Patch #1599256 from David Watson] check that os.fsync is available before using it ........ r53042 | kurt.kaiser | 2006-12-15 06:13:11 +0100 (Fri, 15 Dec 2006) | 6 lines 1. Avoid hang when encountering a duplicate in a completion list. Bug 1571112. 2. Duplicate some old entries from Python's NEWS to IDLE's NEWS.txt M AutoCompleteWindow.py M NEWS.txt ........ r53048 | andrew.kuchling | 2006-12-18 18:12:31 +0100 (Mon, 18 Dec 2006) | 1 line [Bug #1618083] Add missing word; make a few grammar fixes ........ r53050 | andrew.kuchling | 2006-12-18 18:16:05 +0100 (Mon, 18 Dec 2006) | 1 line Bump version ........ r53051 | andrew.kuchling | 2006-12-18 18:22:07 +0100 (Mon, 18 Dec 2006) | 1 line [Bug #1616726] Fix description of generator.close(); if you raise some random exception, the exception is raised and doesn't trigger a RuntimeError ........ r53052 | andrew.kuchling | 2006-12-18 18:38:14 +0100 (Mon, 18 Dec 2006) | 1 line Describe new methods in Queue module ........ r53053 | andrew.kuchling | 2006-12-18 20:22:24 +0100 (Mon, 18 Dec 2006) | 1 line [Patch #1615868 by Lars Gustaebel] Use Py_off_t to fix BZ2File.seek() for offsets > 2Gb ........ r53057 | andrew.kuchling | 2006-12-18 22:29:07 +0100 (Mon, 18 Dec 2006) | 1 line Fix markup ........ r53063 | thomas.wouters | 2006-12-19 09:17:50 +0100 (Tue, 19 Dec 2006) | 5 lines Make sre's SubPattern objects accept slice objects like it already accepts simple slices. ........ r53065 | andrew.kuchling | 2006-12-19 15:13:05 +0100 (Tue, 19 Dec 2006) | 6 lines [Patch #1618455 by Ben Maurer] Improve speed of HMAC by using str.translate() instead of a more general XOR that has to construct a list. Slightly modified from Maurer's patch: the _strxor() function is no longer necessary at all. ........ r53066 | andrew.kuchling | 2006-12-19 15:28:23 +0100 (Tue, 19 Dec 2006) | 9 lines [Bug #1613651] Document socket.recv_into, socket.recvfrom_into Also, the text for recvfrom told you to read recv() for an explanation of the 'flags' argument, but recv() just pointed you at the man page. Copied the man-page text to recvfrom(), recvfrom_into, recv_into to avoid the pointless redirection. I don't have LaTeX on this machine; hope my markup is OK. ........ r53067 | andrew.kuchling | 2006-12-19 15:29:04 +0100 (Tue, 19 Dec 2006) | 1 line Comment typo ........ r53068 | andrew.kuchling | 2006-12-19 16:11:41 +0100 (Tue, 19 Dec 2006) | 1 line [Patch #1617413 from Dug Song] Fix HTTP Basic authentication via HTTPS ........ r53071 | andrew.kuchling | 2006-12-19 16:18:12 +0100 (Tue, 19 Dec 2006) | 1 line [Patch #1600491 from Jim Jewett] Describe how to build help files on Windows ........ r53073 | andrew.kuchling | 2006-12-19 16:43:10 +0100 (Tue, 19 Dec 2006) | 6 lines [Patch #1587139 by kxroberto] Protect lock acquisition/release with try...finally to ensure the lock is always released. This could use the 'with' statement, but the patch uses 'finally'. 2.5 backport candidate. ........ r53074 | vinay.sajip | 2006-12-19 19:29:11 +0100 (Tue, 19 Dec 2006) | 1 line Updated documentation for findCaller() to indicate that a 3-tuple is now returned, rather than a 2-tuple. ........ r53090 | georg.brandl | 2006-12-19 23:06:46 +0100 (Tue, 19 Dec 2006) | 3 lines Patch #1484695: The tarfile module now raises a HeaderError exception if a buffer given to frombuf() is invalid. ........ r53099 | raymond.hettinger | 2006-12-20 07:42:06 +0100 (Wed, 20 Dec 2006) | 5 lines Bug #1590891: random.randrange don't return correct value for big number Needs to be backported. ........ r53106 | georg.brandl | 2006-12-20 12:55:16 +0100 (Wed, 20 Dec 2006) | 3 lines Testcase for patch #1484695. ........ r53110 | andrew.kuchling | 2006-12-20 20:48:20 +0100 (Wed, 20 Dec 2006) | 17 lines [Apply length-checking.diff from bug #1599254] Add length checking to single-file mailbox formats: before doing a flush() on a mailbox, seek to the end and verify its length is unchanged, raising ExternalClashError if the file's length has changed. This fix avoids potential data loss if some other process appends to the mailbox file after the table of contents has been generated; instead of overwriting the modified file, you'll get the exception. I also noticed that the self._lookup() call in self.flush() wasn't necessary (everything that sets self._pending to True also calls self.lookup()), and replaced it by an assertion. 2.5 backport candidate. ........ r53112 | andrew.kuchling | 2006-12-20 20:57:10 +0100 (Wed, 20 Dec 2006) | 1 line [Bug #1619674] Make sum() use the term iterable, not sequence ........ r53113 | andrew.kuchling | 2006-12-20 20:58:11 +0100 (Wed, 20 Dec 2006) | 1 line Two grammar fixes ........ r53115 | andrew.kuchling | 2006-12-20 21:11:12 +0100 (Wed, 20 Dec 2006) | 5 lines Some other built-in functions are described with 'sequence' arguments that should really be 'iterable'; this commit changes them. Did I miss any? Did I introduce any errors? ........ r53117 | andrew.kuchling | 2006-12-20 21:20:42 +0100 (Wed, 20 Dec 2006) | 1 line [Bug #1619680] in_dll() arguments are documented in the wrong order ........ r53120 | neal.norwitz | 2006-12-21 05:38:00 +0100 (Thu, 21 Dec 2006) | 1 line Lars asked for permission on on python-dev for work on tarfile.py ........ r53125 | andrew.kuchling | 2006-12-21 14:40:29 +0100 (Thu, 21 Dec 2006) | 1 line Mention the os.SEEK_* constants ........ r53129 | walter.doerwald | 2006-12-21 19:06:30 +0100 (Thu, 21 Dec 2006) | 2 lines Fix typo. ........ r53131 | thomas.heller | 2006-12-21 19:30:56 +0100 (Thu, 21 Dec 2006) | 3 lines Fix wrong markup of an argument in a method signature. Will backport. ........ r53137 | andrew.kuchling | 2006-12-22 01:50:56 +0100 (Fri, 22 Dec 2006) | 1 line Typo fix ........ r53139 | andrew.kuchling | 2006-12-22 14:25:02 +0100 (Fri, 22 Dec 2006) | 1 line [Bug #737202; fix from Titus Brown] Make CGIHTTPServer work for scripts in sub-directories ........ r53141 | andrew.kuchling | 2006-12-22 16:04:45 +0100 (Fri, 22 Dec 2006) | 6 lines [Bug #802128] Make the mode argument of dumbdbm actually work the way it's described, and add a test for it. 2.5 bugfix candidate, maybe; arguably this patch changes the API of dumbdbm and shouldn't be added in a point-release. ........ r53142 | andrew.kuchling | 2006-12-22 16:16:58 +0100 (Fri, 22 Dec 2006) | 6 lines [Bug #802128 continued] Modify mode depending on the process umask. Is there really no other way to read the umask than to set it? Hope this works on Windows... ........ r53145 | andrew.kuchling | 2006-12-22 17:43:26 +0100 (Fri, 22 Dec 2006) | 1 line [Bug #776202] Apply Walter Doerwald's patch to use text mode for encoded files ........ r53146 | andrew.kuchling | 2006-12-22 19:41:42 +0100 (Fri, 22 Dec 2006) | 9 lines [Patch #783050 from Patrick Lynch] The emulation of forkpty() is incorrect; the master should close the slave fd. Added a test to test_pty.py that reads from the master_fd after doing a pty.fork(); without the fix it hangs forever instead of raising an exception. (<crossing fingers for the buildbots>) 2.5 backport candidate. ........ r53147 | andrew.kuchling | 2006-12-22 20:06:16 +0100 (Fri, 22 Dec 2006) | 1 line [Patch #827559 from Chris Gonnerman] Make SimpleHTTPServer redirect when a directory URL is missing the trailing slash; this lets relative links work. ........ r53149 | andrew.kuchling | 2006-12-22 20:21:27 +0100 (Fri, 22 Dec 2006) | 1 line Darn; this test works when you run test_pty.py directly, but fails when regrtest runs it (the os.read() raises os.error). I can't figure out the cause, so am commenting out the test. ........ r53150 | andrew.kuchling | 2006-12-22 22:48:19 +0100 (Fri, 22 Dec 2006) | 1 line Frak; this test also fails ........ r53153 | lars.gustaebel | 2006-12-23 17:40:13 +0100 (Sat, 23 Dec 2006) | 5 lines Patch #1230446: tarfile.py: fix ExFileObject so that read() and tell() work correctly together with readline(). Will backport to 2.5. ........ r53155 | lars.gustaebel | 2006-12-23 18:57:23 +0100 (Sat, 23 Dec 2006) | 5 lines Patch #1262036: Prevent TarFiles from being added to themselves under certain conditions. Will backport to 2.5. ........ r53159 | andrew.kuchling | 2006-12-27 04:25:31 +0100 (Wed, 27 Dec 2006) | 4 lines [Part of patch #1182394] Move the HMAC blocksize to be a class-level constant; this allows changing it in a subclass. To accommodate this, copy() now uses __class__. Also add some text to a comment. ........ r53160 | andrew.kuchling | 2006-12-27 04:31:24 +0100 (Wed, 27 Dec 2006) | 1 line [Rest of patch #1182394] Add ._current() method so that we can use the written-in-C .hexdigest() method ........ r53161 | lars.gustaebel | 2006-12-27 11:30:46 +0100 (Wed, 27 Dec 2006) | 4 lines Patch #1504073: Fix tarfile.open() for mode "r" with a fileobj argument. Will backport to 2.5. ........ r53165 | neal.norwitz | 2006-12-28 05:39:20 +0100 (Thu, 28 Dec 2006) | 1 line Remove a stray (old) macro name left around (I guess) ........ r53188 | neal.norwitz | 2006-12-29 04:01:53 +0100 (Fri, 29 Dec 2006) | 1 line SF bug #1623890, fix argument name in docstring ........ r53200 | raymond.hettinger | 2006-12-30 05:01:17 +0100 (Sat, 30 Dec 2006) | 1 line For sets with cyclical reprs, emit an ellipsis instead of infinitely recursing. ........ r53232 | brett.cannon | 2007-01-04 01:23:49 +0100 (Thu, 04 Jan 2007) | 3 lines Add EnvironmentVarGuard to test.test_support. Provides a context manager to temporarily set or unset environment variables. ........ r53235 | neal.norwitz | 2007-01-04 07:25:31 +0100 (Thu, 04 Jan 2007) | 1 line SF #1627373, fix typo in CarbonEvt. ........ r53244 | raymond.hettinger | 2007-01-04 18:53:34 +0100 (Thu, 04 Jan 2007) | 1 line Fix stability of heapq's nlargest() and nsmallest(). ........ r53249 | martin.v.loewis | 2007-01-04 22:06:12 +0100 (Thu, 04 Jan 2007) | 3 lines Bug #1566280: Explicitly invoke threading._shutdown from Py_Main, to avoid relying on atexit. Will backport to 2.5. ........ r53252 | gregory.p.smith | 2007-01-05 02:59:42 +0100 (Fri, 05 Jan 2007) | 3 lines Support linking of the bsddb module against BerkeleyDB 4.5.x (will backport to 2.5) ........ r53253 | gregory.p.smith | 2007-01-05 03:06:17 +0100 (Fri, 05 Jan 2007) | 2 lines bump module version to match supported berkeleydb version ........ r53255 | neal.norwitz | 2007-01-05 06:25:22 +0100 (Fri, 05 Jan 2007) | 6 lines Prevent crash on shutdown which can occur if we are finalizing and the module dict has been cleared already and some object raises a warning (like in a __del__). Will backport. ........ r53258 | gregory.p.smith | 2007-01-05 08:21:35 +0100 (Fri, 05 Jan 2007) | 2 lines typo fix ........ r53260 | neal.norwitz | 2007-01-05 09:06:43 +0100 (Fri, 05 Jan 2007) | 1 line Add Collin Winter for access to update PEP 3107 ........ r53262 | andrew.kuchling | 2007-01-05 15:22:17 +0100 (Fri, 05 Jan 2007) | 1 line [Bug #1622533] Make docstrings raw strings because they contain control characters (\0, \1) ........ r53264 | andrew.kuchling | 2007-01-05 16:51:24 +0100 (Fri, 05 Jan 2007) | 1 line [Patch #1520904] Fix bsddb tests to write to the temp directory instead of the Lib/bsddb/test directory ........ r53279 | brett.cannon | 2007-01-05 22:45:09 +0100 (Fri, 05 Jan 2007) | 3 lines Silence a warning from gcc 4.0.1 by specifying a function's parameter list is 'void' instead of just a set of empty parentheses. ........ r53285 | raymond.hettinger | 2007-01-06 02:14:41 +0100 (Sat, 06 Jan 2007) | 2 lines SF# 1409443: Expand comment to cover the interaction between f->f_lasti and the PREDICT macros. ........ r53286 | anthony.baxter | 2007-01-06 05:45:54 +0100 (Sat, 06 Jan 2007) | 1 line update to (c) years to include 2007 ........ r53291 | neal.norwitz | 2007-01-06 22:24:35 +0100 (Sat, 06 Jan 2007) | 1 line Add Josiah to SF for maintaining asyncore/asynchat ........ r53293 | peter.astrand | 2007-01-07 09:53:46 +0100 (Sun, 07 Jan 2007) | 1 line Re-implemented fix for #1531862 once again, in a way that works with Python 2.2. Fixes bug #1603424. ........ r53295 | peter.astrand | 2007-01-07 15:34:16 +0100 (Sun, 07 Jan 2007) | 1 line Avoid O(N**2) bottleneck in _communicate_(). Fixes #1598181. ........ r53300 | raymond.hettinger | 2007-01-08 19:09:20 +0100 (Mon, 08 Jan 2007) | 1 line Fix zero-length corner case for iterating over a mutating deque. ........ r53301 | vinay.sajip | 2007-01-08 19:50:32 +0100 (Mon, 08 Jan 2007) | 4 lines Bare except clause removed from SMTPHandler.emit(). Now, only ImportError is trapped. Bare except clause removed from SocketHandler.createSocket(). Now, only socket.error is trapped. (SF #411881) ........ r53302 | vinay.sajip | 2007-01-08 19:51:46 +0100 (Mon, 08 Jan 2007) | 2 lines Bare except clause removed from LogRecord.__init__. Now, only ValueError, TypeError and AttributeError are trapped. (SF #411881) ........ r53303 | vinay.sajip | 2007-01-08 19:52:36 +0100 (Mon, 08 Jan 2007) | 1 line Added entries about removal of some bare except clauses from logging. ........
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if isinstance(index, slice):
return SubPattern(self.pattern, self.data[index])
return self.data[index]
def __setitem__(self, index, code):
self.data[index] = code
def insert(self, index, code):
self.data.insert(index, code)
def append(self, code):
self.data.append(code)
def getwidth(self):
# determine the width (min, max) for this subpattern
if self.width:
return self.width
lo = hi = 0
UNITCODES = (ANY, RANGE, IN, LITERAL, NOT_LITERAL, CATEGORY)
REPEATCODES = (MIN_REPEAT, MAX_REPEAT)
for op, av in self.data:
if op is BRANCH:
i = sys.maxsize
j = 0
for av in av[1]:
l, h = av.getwidth()
i = min(i, l)
j = max(j, h)
lo = lo + i
hi = hi + j
elif op is CALL:
i, j = av.getwidth()
lo = lo + i
hi = hi + j
elif op is SUBPATTERN:
i, j = av[1].getwidth()
lo = lo + i
hi = hi + j
elif op in REPEATCODES:
i, j = av[2].getwidth()
lo = lo + int(i) * av[0]
hi = hi + int(j) * av[1]
elif op in UNITCODES:
lo = lo + 1
hi = hi + 1
elif op == SUCCESS:
break
self.width = int(min(lo, sys.maxsize)), int(min(hi, sys.maxsize))
return self.width
class Tokenizer:
def __init__(self, string):
self.string = string
self.index = 0
self.__next()
def __next(self):
if self.index >= len(self.string):
self.next = None
return
char = self.string[self.index:self.index+1]
# Special case for the str8, since indexing returns a integer
# XXX This is only needed for test_bug_926075 in test_re.py
if char and isinstance(char, bytes):
char = chr(char[0])
if char == "\\":
try:
c = self.string[self.index + 1]
except IndexError:
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raise error("bogus escape (end of line)")
if isinstance(self.string, bytes):
c = chr(c)
char = char + c
self.index = self.index + len(char)
self.next = char
def match(self, char, skip=1):
if char == self.next:
if skip:
self.__next()
return 1
return 0
def get(self):
this = self.next
self.__next()
return this
def tell(self):
return self.index, self.next
def seek(self, index):
self.index, self.next = index
def isident(char):
return "a" <= char <= "z" or "A" <= char <= "Z" or char == "_"
def isdigit(char):
return "0" <= char <= "9"
def isname(name):
# check that group name is a valid string
if not isident(name[0]):
return False
for char in name[1:]:
if not isident(char) and not isdigit(char):
return False
return True
def _class_escape(source, escape):
# handle escape code inside character class
code = ESCAPES.get(escape)
if code:
return code
code = CATEGORIES.get(escape)
if code:
return code
try:
c = escape[1:2]
if c == "x":
# hexadecimal escape (exactly two digits)
while source.next in HEXDIGITS and len(escape) < 4:
escape = escape + source.get()
escape = escape[2:]
if len(escape) != 2:
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raise error("bogus escape: %s" % repr("\\" + escape))
return LITERAL, int(escape, 16) & 0xff
elif c in OCTDIGITS:
# octal escape (up to three digits)
while source.next in OCTDIGITS and len(escape) < 4:
escape = escape + source.get()
escape = escape[1:]
return LITERAL, int(escape, 8) & 0xff
elif c in DIGITS:
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raise error("bogus escape: %s" % repr(escape))
if len(escape) == 2:
return LITERAL, ord(escape[1])
except ValueError:
pass
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raise error("bogus escape: %s" % repr(escape))
def _escape(source, escape, state):
# handle escape code in expression
code = CATEGORIES.get(escape)
if code:
return code
code = ESCAPES.get(escape)
if code:
return code
try:
c = escape[1:2]
if c == "x":
# hexadecimal escape
while source.next in HEXDIGITS and len(escape) < 4:
escape = escape + source.get()
if len(escape) != 4:
raise ValueError
return LITERAL, int(escape[2:], 16) & 0xff
elif c == "0":
# octal escape
while source.next in OCTDIGITS and len(escape) < 4:
escape = escape + source.get()
return LITERAL, int(escape[1:], 8) & 0xff
elif c in DIGITS:
# octal escape *or* decimal group reference (sigh)
if source.next in DIGITS:
escape = escape + source.get()
if (escape[1] in OCTDIGITS and escape[2] in OCTDIGITS and
source.next in OCTDIGITS):
# got three octal digits; this is an octal escape
escape = escape + source.get()
return LITERAL, int(escape[1:], 8) & 0xff
# not an octal escape, so this is a group reference
group = int(escape[1:])
if group < state.groups:
if not state.checkgroup(group):
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raise error("cannot refer to open group")
return GROUPREF, group
raise ValueError
if len(escape) == 2:
return LITERAL, ord(escape[1])
except ValueError:
pass
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raise error("bogus escape: %s" % repr(escape))
def _parse_sub(source, state, nested=1):
# parse an alternation: a|b|c
items = []
itemsappend = items.append
sourcematch = source.match
while 1:
itemsappend(_parse(source, state))
if sourcematch("|"):
continue
if not nested:
break
if not source.next or sourcematch(")", 0):
break
else:
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raise error("pattern not properly closed")
if len(items) == 1:
return items[0]
subpattern = SubPattern(state)
subpatternappend = subpattern.append
# check if all items share a common prefix
while 1:
prefix = None
for item in items:
if not item:
break
if prefix is None:
prefix = item[0]
elif item[0] != prefix:
break
else:
# all subitems start with a common "prefix".
# move it out of the branch
for item in items:
del item[0]
subpatternappend(prefix)
continue # check next one
break
# check if the branch can be replaced by a character set
for item in items:
if len(item) != 1 or item[0][0] != LITERAL:
break
else:
# we can store this as a character set instead of a
# branch (the compiler may optimize this even more)
set = []
setappend = set.append
for item in items:
setappend(item[0])
subpatternappend((IN, set))
return subpattern
subpattern.append((BRANCH, (None, items)))
return subpattern
def _parse_sub_cond(source, state, condgroup):
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item_yes = _parse(source, state)
if source.match("|"):
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item_no = _parse(source, state)
if source.match("|"):
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raise error("conditional backref with more than two branches")
else:
item_no = None
if source.next and not source.match(")", 0):
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raise error("pattern not properly closed")
subpattern = SubPattern(state)
subpattern.append((GROUPREF_EXISTS, (condgroup, item_yes, item_no)))
return subpattern
_PATTERNENDERS = set("|)")
_ASSERTCHARS = set("=!<")
_LOOKBEHINDASSERTCHARS = set("=!")
_REPEATCODES = set([MIN_REPEAT, MAX_REPEAT])
def _parse(source, state):
# parse a simple pattern
subpattern = SubPattern(state)
# precompute constants into local variables
subpatternappend = subpattern.append
sourceget = source.get
sourcematch = source.match
_len = len
PATTERNENDERS = _PATTERNENDERS
ASSERTCHARS = _ASSERTCHARS
LOOKBEHINDASSERTCHARS = _LOOKBEHINDASSERTCHARS
REPEATCODES = _REPEATCODES
while 1:
if source.next in PATTERNENDERS:
break # end of subpattern
this = sourceget()
if this is None:
break # end of pattern
if state.flags & SRE_FLAG_VERBOSE:
# skip whitespace and comments
if this in WHITESPACE:
continue
if this == "#":
while 1:
this = sourceget()
if this in (None, "\n"):
break
continue
if this and this[0] not in SPECIAL_CHARS:
subpatternappend((LITERAL, ord(this)))
elif this == "[":
# character set
set = []
setappend = set.append
## if sourcematch(":"):
## pass # handle character classes
if sourcematch("^"):
setappend((NEGATE, None))
# check remaining characters
start = set[:]
while 1:
this = sourceget()
if this == "]" and set != start:
break
elif this and this[0] == "\\":
code1 = _class_escape(source, this)
elif this:
code1 = LITERAL, ord(this)
else:
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raise error("unexpected end of regular expression")
if sourcematch("-"):
# potential range
this = sourceget()
if this == "]":
if code1[0] is IN:
code1 = code1[1][0]
setappend(code1)
setappend((LITERAL, ord("-")))
break
elif this:
if this[0] == "\\":
code2 = _class_escape(source, this)
else:
code2 = LITERAL, ord(this)
if code1[0] != LITERAL or code2[0] != LITERAL:
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raise error("bad character range")
lo = code1[1]
hi = code2[1]
if hi < lo:
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raise error("bad character range")
setappend((RANGE, (lo, hi)))
else:
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raise error("unexpected end of regular expression")
else:
if code1[0] is IN:
code1 = code1[1][0]
setappend(code1)
# XXX: <fl> should move set optimization to compiler!
if _len(set)==1 and set[0][0] is LITERAL:
subpatternappend(set[0]) # optimization
elif _len(set)==2 and set[0][0] is NEGATE and set[1][0] is LITERAL:
subpatternappend((NOT_LITERAL, set[1][1])) # optimization
else:
# XXX: <fl> should add charmap optimization here
subpatternappend((IN, set))
elif this and this[0] in REPEAT_CHARS:
# repeat previous item
if this == "?":
min, max = 0, 1
elif this == "*":
min, max = 0, MAXREPEAT
elif this == "+":
min, max = 1, MAXREPEAT
elif this == "{":
if source.next == "}":
subpatternappend((LITERAL, ord(this)))
continue
here = source.tell()
min, max = 0, MAXREPEAT
lo = hi = ""
while source.next in DIGITS:
lo = lo + source.get()
if sourcematch(","):
while source.next in DIGITS:
hi = hi + sourceget()
else:
hi = lo
if not sourcematch("}"):
subpatternappend((LITERAL, ord(this)))
source.seek(here)
continue
if lo:
min = int(lo)
if hi:
max = int(hi)
if max < min:
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raise error("bad repeat interval")
else:
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raise error("not supported")
# figure out which item to repeat
if subpattern:
item = subpattern[-1:]
else:
item = None
if not item or (_len(item) == 1 and item[0][0] == AT):
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raise error("nothing to repeat")
if item[0][0] in REPEATCODES:
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raise error("multiple repeat")
if sourcematch("?"):
subpattern[-1] = (MIN_REPEAT, (min, max, item))
else:
subpattern[-1] = (MAX_REPEAT, (min, max, item))
elif this == ".":
subpatternappend((ANY, None))
elif this == "(":
group = 1
name = None
condgroup = None
if sourcematch("?"):
group = 0
# options
if sourcematch("P"):
# python extensions
if sourcematch("<"):
# named group: skip forward to end of name
name = ""
while 1:
char = sourceget()
if char is None:
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raise error("unterminated name")
if char == ">":
break
name = name + char
group = 1
if not isname(name):
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raise error("bad character in group name")
elif sourcematch("="):
# named backreference
name = ""
while 1:
char = sourceget()
if char is None:
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raise error("unterminated name")
if char == ")":
break
name = name + char
if not isname(name):
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raise error("bad character in group name")
gid = state.groupdict.get(name)
if gid is None:
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raise error("unknown group name")
subpatternappend((GROUPREF, gid))
continue
else:
char = sourceget()
if char is None:
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raise error("unexpected end of pattern")
raise error("unknown specifier: ?P%s" % char)
elif sourcematch(":"):
# non-capturing group
group = 2
elif sourcematch("#"):
# comment
while 1:
if source.next is None or source.next == ")":
break
sourceget()
if not sourcematch(")"):
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raise error("unbalanced parenthesis")
continue
elif source.next in ASSERTCHARS:
# lookahead assertions
char = sourceget()
dir = 1
if char == "<":
if source.next not in LOOKBEHINDASSERTCHARS:
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raise error("syntax error")
dir = -1 # lookbehind
char = sourceget()
p = _parse_sub(source, state)
if not sourcematch(")"):
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raise error("unbalanced parenthesis")
if char == "=":
subpatternappend((ASSERT, (dir, p)))
else:
subpatternappend((ASSERT_NOT, (dir, p)))
continue
elif sourcematch("("):
# conditional backreference group
condname = ""
while 1:
char = sourceget()
if char is None:
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raise error("unterminated name")
if char == ")":
break
condname = condname + char
group = 2
if isname(condname):
condgroup = state.groupdict.get(condname)
if condgroup is None:
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raise error("unknown group name")
else:
try:
condgroup = int(condname)
except ValueError:
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raise error("bad character in group name")
else:
# flags
if not source.next in FLAGS:
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raise error("unexpected end of pattern")
while source.next in FLAGS:
state.flags = state.flags | FLAGS[sourceget()]
if group:
# parse group contents
if group == 2:
# anonymous group
group = None
else:
group = state.opengroup(name)
if condgroup:
p = _parse_sub_cond(source, state, condgroup)
else:
p = _parse_sub(source, state)
if not sourcematch(")"):
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raise error("unbalanced parenthesis")
if group is not None:
state.closegroup(group)
subpatternappend((SUBPATTERN, (group, p)))
else:
while 1:
char = sourceget()
if char is None:
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raise error("unexpected end of pattern")
if char == ")":
break
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raise error("unknown extension")
elif this == "^":
subpatternappend((AT, AT_BEGINNING))
elif this == "$":
subpattern.append((AT, AT_END))
elif this and this[0] == "\\":
code = _escape(source, this, state)
subpatternappend(code)
else:
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raise error("parser error")
return subpattern
def fix_flags(src, flags):
# Check and fix flags according to the type of pattern (str or bytes)
if isinstance(src, str):
if not flags & SRE_FLAG_ASCII:
flags |= SRE_FLAG_UNICODE
elif flags & SRE_FLAG_UNICODE:
raise ValueError("ASCII and UNICODE flags are incompatible")
else:
if flags & SRE_FLAG_UNICODE:
raise ValueError("can't use UNICODE flag with a bytes pattern")
return flags
def parse(str, flags=0, pattern=None):
# parse 're' pattern into list of (opcode, argument) tuples
source = Tokenizer(str)
if pattern is None:
pattern = Pattern()
pattern.flags = flags
pattern.str = str
p = _parse_sub(source, pattern, 0)
p.pattern.flags = fix_flags(str, p.pattern.flags)
tail = source.get()
if tail == ")":
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raise error("unbalanced parenthesis")
elif tail:
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raise error("bogus characters at end of regular expression")
if flags & SRE_FLAG_DEBUG:
p.dump()
if not (flags & SRE_FLAG_VERBOSE) and p.pattern.flags & SRE_FLAG_VERBOSE:
# the VERBOSE flag was switched on inside the pattern. to be
# on the safe side, we'll parse the whole thing again...
return parse(str, p.pattern.flags)
return p
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def parse_template(source, pattern):
# parse 're' replacement string into list of literals and
# group references
s = Tokenizer(source)
sget = s.get
p = []
a = p.append
def literal(literal, p=p, pappend=a):
if p and p[-1][0] is LITERAL:
p[-1] = LITERAL, p[-1][1] + literal
else:
pappend((LITERAL, literal))
sep = source[:0]
if isinstance(sep, str):
makechar = chr
else:
makechar = chr
while 1:
this = sget()
if this is None:
break # end of replacement string
if this and this[0] == "\\":
# group
c = this[1:2]
if c == "g":
name = ""
if s.match("<"):
while 1:
char = sget()
if char is None:
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raise error("unterminated group name")
if char == ">":
break
name = name + char
if not name:
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raise error("bad group name")
try:
index = int(name)
if index < 0:
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raise error("negative group number")
except ValueError:
if not isname(name):
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raise error("bad character in group name")
try:
index = pattern.groupindex[name]
except KeyError:
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raise IndexError("unknown group name")
a((MARK, index))
elif c == "0":
if s.next in OCTDIGITS:
this = this + sget()
if s.next in OCTDIGITS:
this = this + sget()
literal(makechar(int(this[1:], 8) & 0xff))
elif c in DIGITS:
isoctal = False
if s.next in DIGITS:
this = this + sget()
if (c in OCTDIGITS and this[2] in OCTDIGITS and
s.next in OCTDIGITS):
this = this + sget()
isoctal = True
literal(makechar(int(this[1:], 8) & 0xff))
if not isoctal:
a((MARK, int(this[1:])))
else:
try:
this = makechar(ESCAPES[this][1])
except KeyError:
pass
literal(this)
else:
literal(this)
# convert template to groups and literals lists
i = 0
groups = []
groupsappend = groups.append
literals = [None] * len(p)
for c, s in p:
if c is MARK:
groupsappend((i, s))
# literal[i] is already None
else:
literals[i] = s
i = i + 1
return groups, literals
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def expand_template(template, match):
g = match.group
sep = match.string[:0]
groups, literals = template
literals = literals[:]
try:
for index, group in groups:
literals[index] = s = g(group)
if s is None:
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raise error("unmatched group")
except IndexError:
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raise error("invalid group reference")
return sep.join(literals)