| # |
| # 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 |
| 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 |
| |
| def _identityfunction(x): |
| return x |
| |
| _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]) |
| |
| 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 |
| 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") |
| 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 = [] |
| tail = [] |
| charmap = bytearray(256) |
| for op, av in charset: |
| while True: |
| try: |
| if 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 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 |
| 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 len(out) < len(charset): |
| return out |
| 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 |
| _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 |
| import array |
| a = array.array('I', b) |
| 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 |
| ) |