| # | |
| # 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 * | |
| assert _sre.MAGIC == MAGIC, "SRE module mismatch" | |
| if _sre.CODESIZE == 2: | |
| MAXCODE = 65535 | |
| else: | |
| MAXCODE = 0xFFFFFFFFL | |
| 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" | |
| 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 eliminated, 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): | |
| 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 | |
| ) |