#
# 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 *
from _sre import MAXREPEAT
assert _sre.MAGIC == MAGIC, "SRE module mismatch"
if _sre.CODESIZE == 2:
MAXCODE = 65535
else:
MAXCODE = 0xFFFFFFFF
_LITERAL_CODES = set([LITERAL, NOT_LITERAL])
_REPEATING_CODES = set([REPEAT, MIN_REPEAT, MAX_REPEAT])
_SUCCESS_CODES = set([SUCCESS, FAILURE])
_ASSERT_CODES = set([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):
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(OPCODES[IN_IGNORE])
skip = _len(code); emit(0)
if op is NOT_LITERAL:
emit(OPCODES[NEGATE])
for k in (lo,) + fixes[lo]:
emit(OPCODES[LITERAL])
emit(k)
emit(OPCODES[FAILURE])
code[skip] = _len(code) - skip
else:
emit(OPCODES[OP_IGNORE[op]])
emit(lo)
else:
emit(OPCODES[op])
emit(av)
elif op is IN:
if flags & SRE_FLAG_IGNORECASE:
emit(OPCODES[OP_IGNORE[op]])
def fixup(literal, flags=flags):
return _sre.getlower(literal, flags)
else:
emit(OPCODES[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(OPCODES[ANY_ALL])
else:
emit(OPCODES[ANY])
elif op in REPEATING_CODES:
if flags & SRE_FLAG_TEMPLATE:
raise error("internal: unsupported template operator")
elif _simple(av) and op is not REPEAT:
if op is MAX_REPEAT:
emit(OPCODES[REPEAT_ONE])
else:
emit(OPCODES[MIN_REPEAT_ONE])
skip = _len(code); emit(0)
emit(av[0])
emit(av[1])
_compile(code, av[2], flags)
emit(OPCODES[SUCCESS])
code[skip] = _len(code) - skip
else:
emit(OPCODES[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(OPCODES[MAX_UNTIL])
else:
emit(OPCODES[MIN_UNTIL])
elif op is SUBPATTERN:
if av[0]:
emit(OPCODES[MARK])
emit((av[0]-1)*2)
# _compile_info(code, av[1], flags)
_compile(code, av[1], flags)
if av[0]:
emit(OPCODES[MARK])
emit((av[0]-1)*2+1)
elif op in SUCCESS_CODES:
emit(OPCODES[op])
elif op in ASSERT_CODES:
emit(OPCODES[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(OPCODES[SUCCESS])
code[skip] = _len(code) - skip
elif op is CALL:
emit(OPCODES[op])
skip = _len(code); emit(0)
_compile(code, av, flags)
emit(OPCODES[SUCCESS])
code[skip] = _len(code) - skip
elif op is AT:
emit(OPCODES[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(ATCODES[av])
elif op is BRANCH:
emit(OPCODES[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(OPCODES[JUMP])
tailappend(_len(code)); emit(0)
code[skip] = _len(code) - skip
emit(0) # end of branch
for tail in tail:
code[tail] = _len(code) - tail
elif op is CATEGORY:
emit(OPCODES[op])
if flags & SRE_FLAG_LOCALE:
av = CH_LOCALE[av]
elif flags & SRE_FLAG_UNICODE:
av = CH_UNICODE[av]
emit(CHCODES[av])
elif op is GROUPREF:
if flags & SRE_FLAG_IGNORECASE:
emit(OPCODES[OP_IGNORE[op]])
else:
emit(OPCODES[op])
emit(av-1)
elif op is GROUPREF_EXISTS:
emit(OPCODES[op])
emit(av[0]-1)
skipyes = _len(code); emit(0)
_compile(code, av[1], flags)
if av[2]:
emit(OPCODES[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 ValueError("unsupported operand type", 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,
flags & SRE_FLAG_UNICODE):
emit(OPCODES[op])
if op is NEGATE:
pass
elif op is LITERAL:
emit(av)
elif op is RANGE:
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(CHCODES[CH_LOCALE[av]])
elif flags & SRE_FLAG_UNICODE:
emit(CHCODES[CH_UNICODE[av]])
else:
emit(CHCODES[av])
else:
raise error("internal: unsupported set operator")
emit(OPCODES[FAILURE])
def _optimize_charset(charset, fixup, fixes, isunicode):
# internal: optimize character set
out = []
tail = []
charmap = bytearray(256)
for op, av in charset:
while True:
try:
if op is LITERAL:
if fixup:
i = fixup(av)
charmap[i] = 1
if fixes and i in fixes:
for k in fixes[i]:
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
if fixup and isunicode and op is RANGE:
lo, hi = av
ranges = [av]
# There are only two ranges of cased astral characters:
# 10400-1044F (Deseret) and 118A0-118DF (Warang Citi).
_fixup_range(max(0x10000, lo), min(0x11fff, hi),
ranges, fixup)
for lo, hi in ranges:
if lo == hi:
tail.append((LITERAL, hi))
else:
tail.append((RANGE, (lo, hi)))
else:
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
def _fixup_range(lo, hi, ranges, fixup):
for i in map(fixup, range(lo, hi+1)):
for k, (lo, hi) in enumerate(ranges):
if i < lo:
if l == lo - 1:
ranges[k] = (i, hi)
else:
ranges.insert(k, (i, i))
break
elif i > hi:
if i == hi + 1:
ranges[k] = (lo, i)
break
else:
break
else:
ranges.append((i, i))
_CODEBITS = _sre.CODESIZE * 8
_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 _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 lo == 0:
return # not worth it
# look for a literal prefix
prefix = []
prefixappend = prefix.append
prefix_skip = 0
charset = [] # not used
charsetappend = charset.append
if not (flags & SRE_FLAG_IGNORECASE):
# look for literal prefix
for op, av in pattern.data:
if op is LITERAL:
if len(prefix) == prefix_skip:
prefix_skip = prefix_skip + 1
prefixappend(av)
elif op is SUBPATTERN and len(av[1]) == 1:
op, av = av[1][0]
if op is LITERAL:
prefixappend(av)
else:
break
else:
break
# if no prefix, look for charset prefix
if not prefix and pattern.data:
op, av = pattern.data[0]
if op is SUBPATTERN and av[1]:
op, av = av[1][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
## if prefix:
## print "*** PREFIX", prefix, prefix_skip
## if charset:
## print "*** CHARSET", charset
# add an info block
emit = code.append
emit(OPCODES[INFO])
skip = len(code); emit(0)
# literal flag
mask = 0
if prefix:
mask = SRE_INFO_PREFIX
if len(prefix) == prefix_skip == len(pattern.data):
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]
if hi < MAXCODE:
emit(hi)
else:
emit(0)
# add literal prefix
if prefix:
emit(len(prefix)) # length
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(OPCODES[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
# XXX: <fl> get rid of this limitation!
if p.pattern.groups > 100:
raise AssertionError(
"sorry, but this version only supports 100 named groups"
)
# 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
)