Edit File: sre_compile.py
# # 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 * assert _sre.MAGIC == MAGIC, "SRE module mismatch" _LITERAL_CODES = {LITERAL, NOT_LITERAL} _REPEATING_CODES = {REPEAT, MIN_REPEAT, MAX_REPEAT} _SUCCESS_CODES = {SUCCESS, FAILURE} _ASSERT_CODES = {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 and not (flags & SRE_FLAG_ASCII)): 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(IN_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 else: emit(OP_IGNORE[op]) emit(lo) else: emit(op) emit(av) elif op is IN: if flags & SRE_FLAG_IGNORECASE: emit(OP_IGNORE[op]) def fixup(literal, flags=flags): return _sre.getlower(literal, flags) else: emit(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(ANY_ALL) else: emit(ANY) elif op in REPEATING_CODES: if flags & SRE_FLAG_TEMPLATE: raise error("internal: unsupported template operator %r" % (op,)) elif _simple(av) and op is not REPEAT: if op is MAX_REPEAT: emit(REPEAT_ONE) else: emit(MIN_REPEAT_ONE) 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(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(MAX_UNTIL) else: emit(MIN_UNTIL) elif op is SUBPATTERN: group, add_flags, del_flags, p = av if group: emit(MARK) emit((group-1)*2) # _compile_info(code, p, (flags | add_flags) & ~del_flags) _compile(code, p, (flags | add_flags) & ~del_flags) if group: emit(MARK) emit((group-1)*2+1) 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 != 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 CALL: emit(op) skip = _len(code); emit(0) _compile(code, av, 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) and not (flags & SRE_FLAG_ASCII): 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) and not (flags & SRE_FLAG_ASCII): av = CH_UNICODE[av] emit(av) elif op is GROUPREF: if flags & SRE_FLAG_IGNORECASE: emit(OP_IGNORE[op]) else: emit(op) 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, fixup=None, fixes=None): # compile charset subprogram emit = code.append for op, av in _optimize_charset(charset, fixup, fixes): emit(op) if op is NEGATE: pass elif op is LITERAL: emit(av) elif op is RANGE or op is RANGE_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) and not (flags & SRE_FLAG_ASCII): emit(CH_UNICODE[av]) else: emit(av) else: raise error("internal: unsupported set operator %r" % (op,)) emit(FAILURE) def _optimize_charset(charset, fixup, fixes): # internal: optimize character set out = [] tail = [] charmap = bytearray(256) 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 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. # There are only two ranges of cased non-BMP characters: # 10400-1044F (Deseret) and 118A0-118DF (Warang Citi), # and for both ranges RANGE_IGNORE works. if fixup and op is RANGE: op = RANGE_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 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 _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(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 _get_literal_prefix(pattern): # look for literal prefix prefix = [] prefixappend = prefix.append prefix_skip = None for op, av in pattern.data: if op is LITERAL: prefixappend(av) elif op is SUBPATTERN: group, add_flags, del_flags, p = av if add_flags & SRE_FLAG_IGNORECASE: break prefix1, prefix_skip1, got_all = _get_literal_prefix(p) 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): charset = [] # not used charsetappend = charset.append if pattern.data: op, av = pattern.data[0] if op is SUBPATTERN: group, add_flags, del_flags, p = av if p and not (add_flags & SRE_FLAG_IGNORECASE): op, av = p[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 return charset 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): # look for literal prefix prefix, prefix_skip, got_all = _get_literal_prefix(pattern) # if no prefix, look for charset prefix if not prefix: charset = _get_charset_prefix(pattern) ## 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(min(hi, MAXCODE)) # 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: _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(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) # 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 )