#
# Secret Labs' Regular Expression Engine
#
# convert template to internal format
#
# Copyright (c) 1997-2001 by Secret Labs AB. All rights reserved.
#
# See the sre.py file for information on usage and redistribution.
#
"""Internal support module for sre"""
import _sre
import sre_parse
from sre_constants import *
assert _sre.MAGIC == MAGIC, "SRE module mismatch"
_LITERAL_CODES = {LITERAL, NOT_LITERAL}
_REPEATING_CODES = {REPEAT, MIN_REPEAT, MAX_REPEAT}
_SUCCESS_CODES = {SUCCESS, FAILURE}
_ASSERT_CODES = {ASSERT, ASSERT_NOT}
# Sets of lowercase characters which have the same uppercase.
_equivalences = (
# LATIN SMALL LETTER I, LATIN SMALL LETTER DOTLESS I
(0x69, 0x131), # iı
# LATIN SMALL LETTER S, LATIN SMALL LETTER LONG S
(0x73, 0x17f), # sſ
# MICRO SIGN, GREEK SMALL LETTER MU
(0xb5, 0x3bc), # µμ
# COMBINING GREEK YPOGEGRAMMENI, GREEK SMALL LETTER IOTA, GREEK PROSGEGRAMMENI
(0x345, 0x3b9, 0x1fbe), # \u0345ιι
# GREEK SMALL LETTER IOTA WITH DIALYTIKA AND TONOS, GREEK SMALL LETTER IOTA WITH DIALYTIKA AND OXIA
(0x390, 0x1fd3), # ΐΐ
# GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND TONOS, GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND OXIA
(0x3b0, 0x1fe3), # ΰΰ
# GREEK SMALL LETTER BETA, GREEK BETA SYMBOL
(0x3b2, 0x3d0), # βϐ
# GREEK SMALL LETTER EPSILON, GREEK LUNATE EPSILON SYMBOL
(0x3b5, 0x3f5), # εϵ
# GREEK SMALL LETTER THETA, GREEK THETA SYMBOL
(0x3b8, 0x3d1), # θϑ
# GREEK SMALL LETTER KAPPA, GREEK KAPPA SYMBOL
(0x3ba, 0x3f0), # κϰ
# GREEK SMALL LETTER PI, GREEK PI SYMBOL
(0x3c0, 0x3d6), # πϖ
# GREEK SMALL LETTER RHO, GREEK RHO SYMBOL
(0x3c1, 0x3f1), # ρϱ
# GREEK SMALL LETTER FINAL SIGMA, GREEK SMALL LETTER SIGMA
(0x3c2, 0x3c3), # ςσ
# GREEK SMALL LETTER PHI, GREEK PHI SYMBOL
(0x3c6, 0x3d5), # φϕ
# LATIN SMALL LETTER S WITH DOT ABOVE, LATIN SMALL LETTER LONG S WITH DOT ABOVE
(0x1e61, 0x1e9b), # ṡẛ
# LATIN SMALL LIGATURE LONG S T, LATIN SMALL LIGATURE ST
(0xfb05, 0xfb06), # ſtst
)
# Maps the lowercase code to lowercase codes which have the same uppercase.
_ignorecase_fixes = {i: tuple(j for j in t if i != j)
for t in _equivalences for i in t}
def _compile(code, pattern, flags):
# internal: compile a (sub)pattern
emit = code.append
_len = len
LITERAL_CODES = _LITERAL_CODES
REPEATING_CODES = _REPEATING_CODES
SUCCESS_CODES = _SUCCESS_CODES
ASSERT_CODES = _ASSERT_CODES
if (flags & SRE_FLAG_IGNORECASE and
not (flags & SRE_FLAG_LOCALE) and
flags & SRE_FLAG_UNICODE and
not (flags & SRE_FLAG_ASCII)):
fixes = _ignorecase_fixes
else:
fixes = None
for op, av in pattern:
if op in LITERAL_CODES:
if flags & SRE_FLAG_IGNORECASE:
lo = _sre.getlower(av, flags)
if fixes and lo in fixes:
emit(IN_IGNORE)
skip = _len(code); emit(0)
if op is NOT_LITERAL:
emit(NEGATE)
for k in (lo,) + fixes[lo]:
emit(LITERAL)
emit(k)
emit(FAILURE)
code[skip] = _len(code) - skip
else:
emit(OP_IGNORE[op])
emit(lo)
else:
emit(op)
emit(av)
elif op is IN:
if flags & SRE_FLAG_IGNORECASE:
emit(OP_IGNORE[op])
def fixup(literal, flags=flags):
return _sre.getlower(literal, flags)
else:
emit(op)
fixup = None
skip = _len(code); emit(0)
_compile_charset(av, flags, code, fixup, fixes)
code[skip] = _len(code) - skip
elif op is ANY:
if flags & SRE_FLAG_DOTALL:
emit(ANY_ALL)
else:
emit(ANY)
elif op in REPEATING_CODES:
if flags & SRE_FLAG_TEMPLATE:
raise error("internal: unsupported template operator %r" % (op,))
elif _simple(av) and op is not REPEAT:
if op is MAX_REPEAT:
emit(REPEAT_ONE)
else:
emit(MIN_REPEAT_ONE)
skip = _len(code); emit(0)
emit(av[0])
emit(av[1])
_compile(code, av[2], flags)
emit(SUCCESS)
code[skip] = _len(code) - skip
else:
emit(REPEAT)
skip = _len(code); emit(0)
emit(av[0])
emit(av[1])
_compile(code, av[2], flags)
code[skip] = _len(code) - skip
if op is MAX_REPEAT:
emit(MAX_UNTIL)
else:
emit(MIN_UNTIL)
elif op is SUBPATTERN:
group, add_flags, del_flags, p = av
if group:
emit(MARK)
emit((group-1)*2)
# _compile_info(code, p, (flags | add_flags) & ~del_flags)
_compile(code, p, (flags | add_flags) & ~del_flags)
if group:
emit(MARK)
emit((group-1)*2+1)
elif op in SUCCESS_CODES:
emit(op)
elif op in ASSERT_CODES:
emit(op)
skip = _len(code); emit(0)
if av[0] >= 0:
emit(0) # look ahead
else:
lo, hi = av[1].getwidth()
if lo != hi:
raise error("look-behind requires fixed-width pattern")
emit(lo) # look behind
_compile(code, av[1], flags)
emit(SUCCESS)
code[skip] = _len(code) - skip
elif op is CALL:
emit(op)
skip = _len(code); emit(0)
_compile(code, av, flags)
emit(SUCCESS)
code[skip] = _len(code) - skip
elif op is AT:
emit(op)
if flags & SRE_FLAG_MULTILINE:
av = AT_MULTILINE.get(av, av)
if flags & SRE_FLAG_LOCALE:
av = AT_LOCALE.get(av, av)
elif (flags & SRE_FLAG_UNICODE) and not (flags & SRE_FLAG_ASCII):
av = AT_UNICODE.get(av, av)
emit(av)
elif op is BRANCH:
emit(op)
tail = []
tailappend = tail.append
for av in av[1]:
skip = _len(code); emit(0)
# _compile_info(code, av, flags)
_compile(code, av, flags)
emit(JUMP)
tailappend(_len(code)); emit(0)
code[skip] = _len(code) - skip
emit(FAILURE) # end of branch
for tail in tail:
code[tail] = _len(code) - tail
elif op is CATEGORY:
emit(op)
if flags & SRE_FLAG_LOCALE:
av = CH_LOCALE[av]
elif (flags & SRE_FLAG_UNICODE) and not (flags & SRE_FLAG_ASCII):
av = CH_UNICODE[av]
emit(av)
elif op is GROUPREF:
if flags & SRE_FLAG_IGNORECASE:
emit(OP_IGNORE[op])
else:
emit(op)
emit(av-1)
elif op is GROUPREF_EXISTS:
emit(op)
emit(av[0]-1)
skipyes = _len(code); emit(0)
_compile(code, av[1], flags)
if av[2]:
emit(JUMP)
skipno = _len(code); emit(0)
code[skipyes] = _len(code) - skipyes + 1
_compile(code, av[2], flags)
code[skipno] = _len(code) - skipno
else:
code[skipyes] = _len(code) - skipyes + 1
else:
raise error("internal: unsupported operand type %r" % (op,))
def _compile_charset(charset, flags, code, fixup=None, fixes=None):
# compile charset subprogram
emit = code.append
for op, av in _optimize_charset(charset, fixup, fixes):
emit(op)
if op is NEGATE:
pass
elif op is LITERAL:
emit(av)
elif op is RANGE or op is RANGE_IGNORE:
emit(av[0])
emit(av[1])
elif op is CHARSET:
code.extend(av)
elif op is BIGCHARSET:
code.extend(av)
elif op is CATEGORY:
if flags & SRE_FLAG_LOCALE:
emit(CH_LOCALE[av])
elif (flags & SRE_FLAG_UNICODE) and not (flags & SRE_FLAG_ASCII):
emit(CH_UNICODE[av])
else:
emit(av)
else:
raise error("internal: unsupported set operator %r" % (op,))
emit(FAILURE)
def _optimize_charset(charset, fixup, fixes):
# internal: optimize character set
out = []
tail = []
charmap = bytearray(256)
for op, av in charset:
while True:
try:
if op is LITERAL:
if fixup:
lo = fixup(av)
charmap[lo] = 1
if fixes and lo in fixes:
for k in fixes[lo]:
charmap[k] = 1
else:
charmap[av] = 1
elif op is RANGE:
r = range(av[0], av[1]+1)
if fixup:
r = map(fixup, r)
if fixup and fixes:
for i in r:
charmap[i] = 1
if i in fixes:
for k in fixes[i]:
charmap[k] = 1
else:
for i in r:
charmap[i] = 1
elif op is NEGATE:
out.append((op, av))
else:
tail.append((op, av))
except IndexError:
if len(charmap) == 256:
# character set contains non-UCS1 character codes
charmap += b'\0' * 0xff00
continue
# Character set contains non-BMP character codes.
# There are only two ranges of cased non-BMP characters:
# 10400-1044F (Deseret) and 118A0-118DF (Warang Citi),
# and for both ranges RANGE_IGNORE works.
if fixup and op is RANGE:
op = RANGE_IGNORE
tail.append((op, av))
break
# compress character map
runs = []
q = 0
while True:
p = charmap.find(1, q)
if p < 0:
break
if len(runs) >= 2:
runs = None
break
q = charmap.find(0, p)
if q < 0:
runs.append((p, len(charmap)))
break
runs.append((p, q))
if runs is not None:
# use literal/range
for p, q in runs:
if q - p == 1:
out.append((LITERAL, p))
else:
out.append((RANGE, (p, q - 1)))
out += tail
# if the case was changed or new representation is more compact
if fixup or len(out) < len(charset):
return out
# else original character set is good enough
return charset
# use bitmap
if len(charmap) == 256:
data = _mk_bitmap(charmap)
out.append((CHARSET, data))
out += tail
return out
# To represent a big charset, first a bitmap of all characters in the
# set is constructed. Then, this bitmap is sliced into chunks of 256
# characters, duplicate chunks are eliminated, and each chunk is
# given a number. In the compiled expression, the charset is
# represented by a 32-bit word sequence, consisting of one word for
# the number of different chunks, a sequence of 256 bytes (64 words)
# of chunk numbers indexed by their original chunk position, and a
# sequence of 256-bit chunks (8 words each).
# Compression is normally good: in a typical charset, large ranges of
# Unicode will be either completely excluded (e.g. if only cyrillic
# letters are to be matched), or completely included (e.g. if large
# subranges of Kanji match). These ranges will be represented by
# chunks of all one-bits or all zero-bits.
# Matching can be also done efficiently: the more significant byte of
# the Unicode character is an index into the chunk number, and the
# less significant byte is a bit index in the chunk (just like the
# CHARSET matching).
charmap = bytes(charmap) # should be hashable
comps = {}
mapping = bytearray(256)
block = 0
data = bytearray()
for i in range(0, 65536, 256):
chunk = charmap[i: i + 256]
if chunk in comps:
mapping[i // 256] = comps[chunk]
else:
mapping[i // 256] = comps[chunk] = block
block += 1
data += chunk
data = _mk_bitmap(data)
data[0:0] = [block] + _bytes_to_codes(mapping)
out.append((BIGCHARSET, data))
out += tail
return out
_CODEBITS = _sre.CODESIZE * 8
MAXCODE = (1 << _CODEBITS) - 1
_BITS_TRANS = b'0' + b'1' * 255
def _mk_bitmap(bits, _CODEBITS=_CODEBITS, _int=int):
s = bits.translate(_BITS_TRANS)[::-1]
return [_int(s[i - _CODEBITS: i], 2)
for i in range(len(s), 0, -_CODEBITS)]
def _bytes_to_codes(b):
# Convert block indices to word array
a = memoryview(b).cast('I')
assert a.itemsize == _sre.CODESIZE
assert len(a) * a.itemsize == len(b)
return a.tolist()
def _simple(av):
# check if av is a "simple" operator
lo, hi = av[2].getwidth()
return lo == hi == 1 and av[2][0][0] != SUBPATTERN
def _generate_overlap_table(prefix):
"""
Generate an overlap table for the following prefix.
An overlap table is a table of the same size as the prefix which
informs about the potential self-overlap for each index in the prefix:
- if overlap[i] == 0, prefix[i:] can't overlap prefix[0:...]
- if overlap[i] == k with 0 < k <= i, prefix[i-k+1:i+1] overlaps with
prefix[0:k]
"""
table = [0] * len(prefix)
for i in range(1, len(prefix)):
idx = table[i - 1]
while prefix[i] != prefix[idx]:
if idx == 0:
table[i] = 0
break
idx = table[idx - 1]
else:
table[i] = idx + 1
return table
def _get_literal_prefix(pattern):
# look for literal prefix
prefix = []
prefixappend = prefix.append
prefix_skip = None
for op, av in pattern.data:
if op is LITERAL:
prefixappend(av)
elif op is SUBPATTERN:
group, add_flags, del_flags, p = av
if add_flags & SRE_FLAG_IGNORECASE:
break
prefix1, prefix_skip1, got_all = _get_literal_prefix(p)
if prefix_skip is None:
if group is not None:
prefix_skip = len(prefix)
elif prefix_skip1 is not None:
prefix_skip = len(prefix) + prefix_skip1
prefix.extend(prefix1)
if not got_all:
break
else:
break
else:
return prefix, prefix_skip, True
return prefix, prefix_skip, False
def _get_charset_prefix(pattern):
charset = [] # not used
charsetappend = charset.append
if pattern.data:
op, av = pattern.data[0]
if op is SUBPATTERN:
group, add_flags, del_flags, p = av
if p and not (add_flags & SRE_FLAG_IGNORECASE):
op, av = p[0]
if op is LITERAL:
charsetappend((op, av))
elif op is BRANCH:
c = []
cappend = c.append
for p in av[1]:
if not p:
break
op, av = p[0]
if op is LITERAL:
cappend((op, av))
else:
break
else:
charset = c
elif op is BRANCH:
c = []
cappend = c.append
for p in av[1]:
if not p:
break
op, av = p[0]
if op is LITERAL:
cappend((op, av))
else:
break
else:
charset = c
elif op is IN:
charset = av
return charset
def _compile_info(code, pattern, flags):
# internal: compile an info block. in the current version,
# this contains min/max pattern width, and an optional literal
# prefix or a character map
lo, hi = pattern.getwidth()
if hi > MAXCODE:
hi = MAXCODE
if lo == 0:
code.extend([INFO, 4, 0, lo, hi])
return
# look for a literal prefix
prefix = []
prefix_skip = 0
charset = [] # not used
if not (flags & SRE_FLAG_IGNORECASE):
# look for literal prefix
prefix, prefix_skip, got_all = _get_literal_prefix(pattern)
# if no prefix, look for charset prefix
if not prefix:
charset = _get_charset_prefix(pattern)
## if prefix:
## print("*** PREFIX", prefix, prefix_skip)
## if charset:
## print("*** CHARSET", charset)
# add an info block
emit = code.append
emit(INFO)
skip = len(code); emit(0)
# literal flag
mask = 0
if prefix:
mask = SRE_INFO_PREFIX
if prefix_skip is None and got_all:
mask = mask | SRE_INFO_LITERAL
elif charset:
mask = mask | SRE_INFO_CHARSET
emit(mask)
# pattern length
if lo < MAXCODE:
emit(lo)
else:
emit(MAXCODE)
prefix = prefix[:MAXCODE]
emit(min(hi, MAXCODE))
# add literal prefix
if prefix:
emit(len(prefix)) # length
if prefix_skip is None:
prefix_skip = len(prefix)
emit(prefix_skip) # skip
code.extend(prefix)
# generate overlap table
code.extend(_generate_overlap_table(prefix))
elif charset:
_compile_charset(charset, flags, code)
code[skip] = len(code) - skip
def isstring(obj):
return isinstance(obj, (str, bytes))
def _code(p, flags):
flags = p.pattern.flags | flags
code = []
# compile info block
_compile_info(code, p, flags)
# compile the pattern
_compile(code, p.data, flags)
code.append(SUCCESS)
return code
def compile(p, flags=0):
# internal: convert pattern list to internal format
if isstring(p):
pattern = p
p = sre_parse.parse(p, flags)
else:
pattern = None
code = _code(p, flags)
# print(code)
# map in either direction
groupindex = p.pattern.groupdict
indexgroup = [None] * p.pattern.groups
for k, i in groupindex.items():
indexgroup[i] = k
return _sre.compile(
pattern, flags | p.pattern.flags, code,
p.pattern.groups-1,
groupindex, indexgroup
)
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