521 lines
16 KiB
Python
521 lines
16 KiB
Python
#
|
|
# 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, sys
|
|
|
|
from sre_constants import *
|
|
|
|
assert _sre.MAGIC == MAGIC, "SRE module mismatch"
|
|
|
|
if _sre.CODESIZE == 2:
|
|
MAXCODE = 65535
|
|
else:
|
|
MAXCODE = 0xFFFFFFFFL
|
|
|
|
def _identityfunction(x):
|
|
return x
|
|
|
|
def _compile(code, pattern, flags):
|
|
# internal: compile a (sub)pattern
|
|
emit = code.append
|
|
_len = len
|
|
LITERAL_CODES = {LITERAL:1, NOT_LITERAL:1}
|
|
REPEATING_CODES = {REPEAT:1, MIN_REPEAT:1, MAX_REPEAT:1}
|
|
SUCCESS_CODES = {SUCCESS:1, FAILURE:1}
|
|
ASSERT_CODES = {ASSERT:1, ASSERT_NOT:1}
|
|
for op, av in pattern:
|
|
if op in LITERAL_CODES:
|
|
if flags & SRE_FLAG_IGNORECASE:
|
|
emit(OPCODES[OP_IGNORE[op]])
|
|
emit(_sre.getlower(av, flags))
|
|
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 = _identityfunction
|
|
skip = _len(code); emit(0)
|
|
_compile_charset(av, flags, code, fixup)
|
|
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"
|
|
emit(OPCODES[REPEAT])
|
|
skip = _len(code); emit(0)
|
|
emit(av[0])
|
|
emit(av[1])
|
|
_compile(code, av[2], flags)
|
|
emit(OPCODES[SUCCESS])
|
|
code[skip] = _len(code) - skip
|
|
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):
|
|
# compile charset subprogram
|
|
emit = code.append
|
|
if fixup is None:
|
|
fixup = _identityfunction
|
|
for op, av in _optimize_charset(charset, fixup):
|
|
emit(OPCODES[op])
|
|
if op is NEGATE:
|
|
pass
|
|
elif op is LITERAL:
|
|
emit(fixup(av))
|
|
elif op is RANGE:
|
|
emit(fixup(av[0]))
|
|
emit(fixup(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):
|
|
# internal: optimize character set
|
|
out = []
|
|
outappend = out.append
|
|
charmap = [0]*256
|
|
try:
|
|
for op, av in charset:
|
|
if op is NEGATE:
|
|
outappend((op, av))
|
|
elif op is LITERAL:
|
|
charmap[fixup(av)] = 1
|
|
elif op is RANGE:
|
|
for i in range(fixup(av[0]), fixup(av[1])+1):
|
|
charmap[i] = 1
|
|
elif op is CATEGORY:
|
|
# XXX: could append to charmap tail
|
|
return charset # cannot compress
|
|
except IndexError:
|
|
# character set contains unicode characters
|
|
return _optimize_unicode(charset, fixup)
|
|
# compress character map
|
|
i = p = n = 0
|
|
runs = []
|
|
runsappend = runs.append
|
|
for c in charmap:
|
|
if c:
|
|
if n == 0:
|
|
p = i
|
|
n = n + 1
|
|
elif n:
|
|
runsappend((p, n))
|
|
n = 0
|
|
i = i + 1
|
|
if n:
|
|
runsappend((p, n))
|
|
if len(runs) <= 2:
|
|
# use literal/range
|
|
for p, n in runs:
|
|
if n == 1:
|
|
outappend((LITERAL, p))
|
|
else:
|
|
outappend((RANGE, (p, p+n-1)))
|
|
if len(out) < len(charset):
|
|
return out
|
|
else:
|
|
# use bitmap
|
|
data = _mk_bitmap(charmap)
|
|
outappend((CHARSET, data))
|
|
return out
|
|
return charset
|
|
|
|
def _mk_bitmap(bits):
|
|
data = []
|
|
dataappend = data.append
|
|
if _sre.CODESIZE == 2:
|
|
start = (1, 0)
|
|
else:
|
|
start = (1L, 0L)
|
|
m, v = start
|
|
for c in bits:
|
|
if c:
|
|
v = v + m
|
|
m = m + m
|
|
if m > MAXCODE:
|
|
dataappend(v)
|
|
m, v = start
|
|
return data
|
|
|
|
# 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 eliminitated, and each chunk is
|
|
# given a number. In the compiled expression, the charset is
|
|
# represented by a 16-bit word sequence, consisting of one word for
|
|
# the number of different chunks, a sequence of 256 bytes (128 words)
|
|
# of chunk numbers indexed by their original chunk position, and a
|
|
# sequence of chunks (16 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).
|
|
|
|
# In UCS-4 mode, the BIGCHARSET opcode still supports only subsets
|
|
# of the basic multilingual plane; an efficient representation
|
|
# for all of UTF-16 has not yet been developed. This means,
|
|
# in particular, that negated charsets cannot be represented as
|
|
# bigcharsets.
|
|
|
|
def _optimize_unicode(charset, fixup):
|
|
try:
|
|
import array
|
|
except ImportError:
|
|
return charset
|
|
charmap = [0]*65536
|
|
negate = 0
|
|
try:
|
|
for op, av in charset:
|
|
if op is NEGATE:
|
|
negate = 1
|
|
elif op is LITERAL:
|
|
charmap[fixup(av)] = 1
|
|
elif op is RANGE:
|
|
for i in xrange(fixup(av[0]), fixup(av[1])+1):
|
|
charmap[i] = 1
|
|
elif op is CATEGORY:
|
|
# XXX: could expand category
|
|
return charset # cannot compress
|
|
except IndexError:
|
|
# non-BMP characters
|
|
return charset
|
|
if negate:
|
|
if sys.maxunicode != 65535:
|
|
# XXX: negation does not work with big charsets
|
|
return charset
|
|
for i in xrange(65536):
|
|
charmap[i] = not charmap[i]
|
|
comps = {}
|
|
mapping = [0]*256
|
|
block = 0
|
|
data = []
|
|
for i in xrange(256):
|
|
chunk = tuple(charmap[i*256:(i+1)*256])
|
|
new = comps.setdefault(chunk, block)
|
|
mapping[i] = new
|
|
if new == block:
|
|
block = block + 1
|
|
data = data + _mk_bitmap(chunk)
|
|
header = [block]
|
|
if _sre.CODESIZE == 2:
|
|
code = 'H'
|
|
else:
|
|
code = 'I'
|
|
# Convert block indices to byte array of 256 bytes
|
|
mapping = array.array('b', mapping).tostring()
|
|
# Convert byte array to word array
|
|
mapping = array.array(code, mapping)
|
|
assert mapping.itemsize == _sre.CODESIZE
|
|
header = header + mapping.tolist()
|
|
data[0:0] = header
|
|
return [(BIGCHARSET, data)]
|
|
|
|
def _simple(av):
|
|
# check if av is a "simple" operator
|
|
lo, hi = av[2].getwidth()
|
|
if lo == 0 and hi == MAXREPEAT:
|
|
raise error, "nothing to repeat"
|
|
return lo == hi == 1 and av[2][0][0] != SUBPATTERN
|
|
|
|
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
|
|
table = [-1] + ([0]*len(prefix))
|
|
for i in xrange(len(prefix)):
|
|
table[i+1] = table[i]+1
|
|
while table[i+1] > 0 and prefix[i] != prefix[table[i+1]-1]:
|
|
table[i+1] = table[table[i+1]-1]+1
|
|
code.extend(table[1:]) # don't store first entry
|
|
elif charset:
|
|
_compile_charset(charset, flags, code)
|
|
code[skip] = len(code) - skip
|
|
|
|
try:
|
|
unicode
|
|
except NameError:
|
|
STRING_TYPES = (type(""),)
|
|
else:
|
|
STRING_TYPES = (type(""), type(unicode("")))
|
|
|
|
def isstring(obj):
|
|
for tp in STRING_TYPES:
|
|
if isinstance(obj, tp):
|
|
return 1
|
|
return 0
|
|
|
|
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):
|
|
import sre_parse
|
|
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, code,
|
|
p.pattern.groups-1,
|
|
groupindex, indexgroup
|
|
)
|