#
# Secret Labs' Regular Expression Engine
#
# convert template to internal format
#
# Copyright (c) 1997-2001 by Secret Labs AB. All rights reserved.
#
# See the __init__.py file for information on usage and redistribution.
#
"""Internal support module for sre"""
import _sre
from . import _parser
from ._constants import *
from ._casefix import _EXTRA_CASES
assert _sre.MAGIC == MAGIC, "SRE module mismatch"
_LITERAL_CODES = {LITERAL, NOT_LITERAL}
_SUCCESS_CODES = {SUCCESS, FAILURE}
_ASSERT_CODES = {ASSERT, ASSERT_NOT}
_UNIT_CODES = _LITERAL_CODES | {ANY, IN}
_REPEATING_CODES = {
MIN_REPEAT: (REPEAT, MIN_UNTIL, MIN_REPEAT_ONE),
MAX_REPEAT: (REPEAT, MAX_UNTIL, REPEAT_ONE),
POSSESSIVE_REPEAT: (POSSESSIVE_REPEAT, SUCCESS, POSSESSIVE_REPEAT_ONE),
}
def _combine_flags(flags, add_flags, del_flags,
TYPE_FLAGS=_parser.TYPE_FLAGS):
if add_flags & TYPE_FLAGS:
flags &= ~TYPE_FLAGS
return (flags | add_flags) & ~del_flags
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
iscased = None
tolower = None
fixes = None
if flags & SRE_FLAG_IGNORECASE and not flags & SRE_FLAG_LOCALE:
if flags & SRE_FLAG_UNICODE:
iscased = _sre.unicode_iscased
tolower = _sre.unicode_tolower
fixes = _EXTRA_CASES
else:
iscased = _sre.ascii_iscased
tolower = _sre.ascii_tolower
for op, av in pattern:
if op in LITERAL_CODES:
if not flags & SRE_FLAG_IGNORECASE:
emit(op)
emit(av)
elif flags & SRE_FLAG_LOCALE:
emit(OP_LOCALE_IGNORE[op])
emit(av)
elif not iscased(av):
emit(op)
emit(av)
else:
lo = tolower(av)
if not fixes: # ascii
emit(OP_IGNORE[op])
emit(lo)
elif lo not in fixes:
emit(OP_UNICODE_IGNORE[op])
emit(lo)
else:
emit(IN_UNI_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
elif op is IN:
charset, hascased = _optimize_charset(av, iscased, tolower, fixes)
if flags & SRE_FLAG_IGNORECASE and flags & SRE_FLAG_LOCALE:
emit(IN_LOC_IGNORE)
elif not hascased:
emit(IN)
elif not fixes: # ascii
emit(IN_IGNORE)
else:
emit(IN_UNI_IGNORE)
skip = _len(code); emit(0)
_compile_charset(charset, flags, code)
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,))
if _simple(av[2]):
emit(REPEATING_CODES[op][2])
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(REPEATING_CODES[op][0])
skip = _len(code); emit(0)
emit(av[0])
emit(av[1])
_compile(code, av[2], flags)
code[skip] = _len(code) - skip
emit(REPEATING_CODES[op][1])
elif op is SUBPATTERN:
group, add_flags, del_flags, p = av
if group:
emit(MARK)
emit((group-1)*2)
# _compile_info(code, p, _combine_flags(flags, add_flags, del_flags))
_compile(code, p, _combine_flags(flags, add_flags, del_flags))
if group:
emit(MARK)
emit((group-1)*2+1)
elif op is ATOMIC_GROUP:
# Atomic Groups are handled by starting with an Atomic
# Group op code, then putting in the atomic group pattern
# and finally a success op code to tell any repeat
# operations within the Atomic Group to stop eating and
# pop their stack if they reach it
emit(ATOMIC_GROUP)
skip = _len(code); emit(0)
_compile(code, av, flags)
emit(SUCCESS)
code[skip] = _len(code) - skip
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 > MAXCODE:
raise error("looks too much behind")
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 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:
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:
av = CH_UNICODE[av]
emit(av)
elif op is GROUPREF:
if not flags & SRE_FLAG_IGNORECASE:
emit(op)
elif flags & SRE_FLAG_LOCALE:
emit(GROUPREF_LOC_IGNORE)
elif not fixes: # ascii
emit(GROUPREF_IGNORE)
else:
emit(GROUPREF_UNI_IGNORE)
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):
# compile charset subprogram
emit = code.append
for op, av in charset:
emit(op)
if op is NEGATE:
pass
elif op is LITERAL:
emit(av)
elif op is RANGE or op is RANGE_UNI_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:
emit(CH_UNICODE[av])
else:
emit(av)
else:
raise error("internal: unsupported set operator %r" % (op,))
emit(FAILURE)
def _optimize_charset(charset, iscased=None, fixup=None, fixes=None):
# internal: optimize character set
out = []
tail = []
charmap = bytearray(256)
hascased = False
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
if not hascased and iscased(av):
hascased = True
else:
charmap[av] = 1
elif op is RANGE:
r = range(av[0], av[1]+1)
if fixup:
if fixes:
for i in map(fixup, r):
charmap[i] = 1
if i in fixes:
for k in fixes[i]:
charmap[k] = 1
else:
for i in map(fixup, r):
charmap[i] = 1
if not hascased:
hascased = any(map(iscased, r))
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.
# For range, all BMP characters in the range are already
# proceeded.
if fixup:
hascased = True
# For now, IN_UNI_IGNORE+LITERAL and
# IN_UNI_IGNORE+RANGE_UNI_IGNORE work for all non-BMP
# characters, because two characters (at least one of
# which is not in the BMP) match case-insensitively
# if and only if:
# 1) c1.lower() == c2.lower()
# 2) c1.lower() == c2 or c1.lower().upper() == c2
# Also, both c.lower() and c.lower().upper() are single
# characters for every non-BMP character.
if op is RANGE:
op = RANGE_UNI_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 hascased or len(out) < len(charset):
return out, hascased
# else original character set is good enough
return charset, hascased
# use bitmap
if len(charmap) == 256:
data = _mk_bitmap(charmap)
out.append((CHARSET, data))
out += tail
return out, hascased
# 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, hascased
_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(p):
# check if this subpattern is a "simple" operator
if len(p) != 1:
return False
op, av = p[0]
if op is SUBPATTERN:
return av[0] is None and _simple(av[-1])
return op in _UNIT_CODES
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_iscased(flags):
if not flags & SRE_FLAG_IGNORECASE:
return None
elif flags & SRE_FLAG_UNICODE:
return _sre.unicode_iscased
else:
return _sre.ascii_iscased
def _get_literal_prefix(pattern, flags):
# look for literal prefix
prefix = []
prefixappend = prefix.append
prefix_skip = None
iscased = _get_iscased(flags)
for op, av in pattern.data:
if op is LITERAL:
if iscased and iscased(av):
break
prefixappend(av)
elif op is SUBPATTERN:
group, add_flags, del_flags, p = av
flags1 = _combine_flags(flags, add_flags, del_flags)
if flags1 & SRE_FLAG_IGNORECASE and flags1 & SRE_FLAG_LOCALE:
break
prefix1, prefix_skip1, got_all = _get_literal_prefix(p, flags1)
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, flags):
while True:
if not pattern.data:
return None
op, av = pattern.data[0]
if op is not SUBPATTERN:
break
group, add_flags, del_flags, pattern = av
flags = _combine_flags(flags, add_flags, del_flags)
if flags & SRE_FLAG_IGNORECASE and flags & SRE_FLAG_LOCALE:
return None
iscased = _get_iscased(flags)
if op is LITERAL:
if iscased and iscased(av):
return None
return [(op, av)]
elif op is BRANCH:
charset = []
charsetappend = charset.append
for p in av[1]:
if not p:
return None
op, av = p[0]
if op is LITERAL and not (iscased and iscased(av)):
charsetappend((op, av))
else:
return None
return charset
elif op is IN:
charset = av
if iscased:
for op, av in charset:
if op is LITERAL:
if iscased(av):
return None
elif op is RANGE:
if av[1] > 0xffff:
return None
if any(map(iscased, range(av[0], av[1]+1))):
return None
return charset
return None
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 and flags & SRE_FLAG_LOCALE):
# look for literal prefix
prefix, prefix_skip, got_all = _get_literal_prefix(pattern, flags)
# if no prefix, look for charset prefix
if not prefix:
charset = _get_charset_prefix(pattern, flags)
## 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(hi)
# 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:
charset, hascased = _optimize_charset(charset)
assert not hascased
_compile_charset(charset, flags, code)
code[skip] = len(code) - skip
def isstring(obj):
return isinstance(obj, (str, bytes))
def _code(p, flags):
flags = p.state.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 _hex_code(code):
return '[%s]' % ', '.join('%#0*x' % (_sre.CODESIZE*2+2, x) for x in code)
def dis(code):
import sys
labels = set()
level = 0
offset_width = len(str(len(code) - 1))
def dis_(start, end):
def print_(*args, to=None):
if to is not None:
labels.add(to)
args += ('(to %d)' % (to,),)
print('%*d%s ' % (offset_width, start, ':' if start in labels else '.'),
end=' '*(level-1))
print(*args)
def print_2(*args):
print(end=' '*(offset_width + 2*level))
print(*args)
nonlocal level
level += 1
i = start
while i < end:
start = i
op = code[i]
i += 1
op = OPCODES[op]
if op in (SUCCESS, FAILURE, ANY, ANY_ALL,
MAX_UNTIL, MIN_UNTIL, NEGATE):
print_(op)
elif op in (LITERAL, NOT_LITERAL,
LITERAL_IGNORE, NOT_LITERAL_IGNORE,
LITERAL_UNI_IGNORE, NOT_LITERAL_UNI_IGNORE,
LITERAL_LOC_IGNORE, NOT_LITERAL_LOC_IGNORE):
arg = code[i]
i += 1
print_(op, '%#02x (%r)' % (arg, chr(arg)))
elif op is AT:
arg = code[i]
i += 1
arg = str(ATCODES[arg])
assert arg[:3] == 'AT_'
print_(op, arg[3:])
elif op is CATEGORY:
arg = code[i]
i += 1
arg = str(CHCODES[arg])
assert arg[:9] == 'CATEGORY_'
print_(op, arg[9:])
elif op in (IN, IN_IGNORE, IN_UNI_IGNORE, IN_LOC_IGNORE):
skip = code[i]
print_(op, skip, to=i+skip)
dis_(i+1, i+skip)
i += skip
elif op in (RANGE, RANGE_UNI_IGNORE):
lo, hi = code[i: i+2]
i += 2
print_(op, '%#02x %#02x (%r-%r)' % (lo, hi, chr(lo), chr(hi)))
elif op is CHARSET:
print_(op, _hex_code(code[i: i + 256//_CODEBITS]))
i += 256//_CODEBITS
elif op is BIGCHARSET:
arg = code[i]
i += 1
mapping = list(b''.join(x.to_bytes(_sre.CODESIZE, sys.byteorder)
for x in code[i: i + 256//_sre.CODESIZE]))
print_(op, arg, mapping)
i += 256//_sre.CODESIZE
level += 1
for j in range(arg):
print_2(_hex_code(code[i: i + 256//_CODEBITS]))
i += 256//_CODEBITS
level -= 1
elif op in (MARK, GROUPREF, GROUPREF_IGNORE, GROUPREF_UNI_IGNORE,
GROUPREF_LOC_IGNORE):
arg = code[i]
i += 1
print_(op, arg)
elif op is JUMP:
skip = code[i]
print_(op, skip, to=i+skip)
i += 1
elif op is BRANCH:
skip = code[i]
print_(op, skip, to=i+skip)
while skip:
dis_(i+1, i+skip)
i += skip
start = i
skip = code[i]
if skip:
print_('branch', skip, to=i+skip)
else:
print_(FAILURE)
i += 1
elif op in (REPEAT, REPEAT_ONE, MIN_REPEAT_ONE,
POSSESSIVE_REPEAT, POSSESSIVE_REPEAT_ONE):
skip, min, max = code[i: i+3]
if max == MAXREPEAT:
max = 'MAXREPEAT'
print_(op, skip, min, max, to=i+skip)
dis_(i+3, i+skip)
i += skip
elif op is GROUPREF_EXISTS:
arg, skip = code[i: i+2]
print_(op, arg, skip, to=i+skip)
i += 2
elif op in (ASSERT, ASSERT_NOT):
skip, arg = code[i: i+2]
print_(op, skip, arg, to=i+skip)
dis_(i+2, i+skip)
i += skip
elif op is ATOMIC_GROUP:
skip = code[i]
print_(op, skip, to=i+skip)
dis_(i+1, i+skip)
i += skip
elif op is INFO:
skip, flags, min, max = code[i: i+4]
if max == MAXREPEAT:
max = 'MAXREPEAT'
print_(op, skip, bin(flags), min, max, to=i+skip)
start = i+4
if flags & SRE_INFO_PREFIX:
prefix_len, prefix_skip = code[i+4: i+6]
print_2(' prefix_skip', prefix_skip)
start = i + 6
prefix = code[start: start+prefix_len]
print_2(' prefix',
'[%s]' % ', '.join('%#02x' % x for x in prefix),
'(%r)' % ''.join(map(chr, prefix)))
start += prefix_len
print_2(' overlap', code[start: start+prefix_len])
start += prefix_len
if flags & SRE_INFO_CHARSET:
level += 1
print_2('in')
dis_(start, i+skip)
level -= 1
i += skip
else:
raise ValueError(op)
level -= 1
dis_(0, len(code))
def compile(p, flags=0):
# internal: convert pattern list to internal format
if isstring(p):
pattern = p
p = _parser.parse(p, flags)
else:
pattern = None
code = _code(p, flags)
if flags & SRE_FLAG_DEBUG:
print()
dis(code)
# map in either direction
groupindex = p.state.groupdict
indexgroup = [None] * p.state.groups
for k, i in groupindex.items():
indexgroup[i] = k
return _sre.compile(
pattern, flags | p.state.flags, code,
p.state.groups-1,
groupindex, tuple(indexgroup)
)
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