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_compiler.py
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# # Secret Labs' Regular Expression Engine # # convert template to internal format # # Copyright (c) 1997-2001 by Secret Labs AB. All rights reserved. # # See the __init__.py file for information on usage and redistribution. # """Internal support module for sre""" import _sre from . import _parser from ._constants import * from ._casefix import _EXTRA_CASES assert _sre.MAGIC == MAGIC, "SRE module mismatch" _LITERAL_CODES = {LITERAL, NOT_LITERAL} _SUCCESS_CODES = {SUCCESS, FAILURE} _ASSERT_CODES = {ASSERT, ASSERT_NOT} _UNIT_CODES = _LITERAL_CODES | {ANY, IN} _REPEATING_CODES = { MIN_REPEAT: (REPEAT, MIN_UNTIL, MIN_REPEAT_ONE), MAX_REPEAT: (REPEAT, MAX_UNTIL, REPEAT_ONE), POSSESSIVE_REPEAT: (POSSESSIVE_REPEAT, SUCCESS, POSSESSIVE_REPEAT_ONE), } _CHARSET_ALL = [(NEGATE, None)] def _combine_flags(flags, add_flags, del_flags, TYPE_FLAGS=_parser.TYPE_FLAGS): if add_flags & TYPE_FLAGS: flags &= ~TYPE_FLAGS return (flags | add_flags) & ~del_flags 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 iscased = None tolower = None fixes = None if flags & SRE_FLAG_IGNORECASE and not flags & SRE_FLAG_LOCALE: if flags & SRE_FLAG_UNICODE: iscased = _sre.unicode_iscased tolower = _sre.unicode_tolower fixes = _EXTRA_CASES else: iscased = _sre.ascii_iscased tolower = _sre.ascii_tolower for op, av in pattern: if op in LITERAL_CODES: if not flags & SRE_FLAG_IGNORECASE: emit(op) emit(av) elif flags & SRE_FLAG_LOCALE: emit(OP_LOCALE_IGNORE[op]) emit(av) elif not iscased(av): emit(op) emit(av) else: lo = tolower(av) if not fixes: # ascii emit(OP_IGNORE[op]) emit(lo) elif lo not in fixes: emit(OP_UNICODE_IGNORE[op]) emit(lo) else: emit(IN_UNI_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 elif op is IN: charset, hascased = _optimize_charset(av, iscased, tolower, fixes) if not charset: emit(FAILURE) elif charset == _CHARSET_ALL: emit(ANY_ALL) else: if flags & SRE_FLAG_IGNORECASE and flags & SRE_FLAG_LOCALE: emit(IN_LOC_IGNORE) elif not hascased: emit(IN) elif not fixes: # ascii emit(IN_IGNORE) else: emit(IN_UNI_IGNORE) skip = _len(code); emit(0) _compile_charset(charset, flags, code) 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 _simple(av[2]): emit(REPEATING_CODES[op][2]) 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(REPEATING_CODES[op][0]) skip = _len(code); emit(0) emit(av[0]) emit(av[1]) _compile(code, av[2], flags) code[skip] = _len(code) - skip emit(REPEATING_CODES[op][1]) elif op is SUBPATTERN: group, add_flags, del_flags, p = av if group: emit(MARK) emit((group-1)*2) # _compile_info(code, p, _combine_flags(flags, add_flags, del_flags)) _compile(code, p, _combine_flags(flags, add_flags, del_flags)) if group: emit(MARK) emit((group-1)*2+1) elif op is ATOMIC_GROUP: # Atomic Groups are handled by starting with an Atomic # Group op code, then putting in the atomic group pattern # and finally a success op code to tell any repeat # operations within the Atomic Group to stop eating and # pop their stack if they reach it emit(ATOMIC_GROUP) skip = _len(code); emit(0) _compile(code, av, flags) emit(SUCCESS) code[skip] = _len(code) - skip 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 > MAXCODE: raise error("looks too much behind") if lo != hi: raise PatternError("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 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: 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: av = CH_UNICODE[av] emit(av) elif op is GROUPREF: if not flags & SRE_FLAG_IGNORECASE: emit(op) elif flags & SRE_FLAG_LOCALE: emit(GROUPREF_LOC_IGNORE) elif not fixes: # ascii emit(GROUPREF_IGNORE) else: emit(GROUPREF_UNI_IGNORE) 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 PatternError(f"internal: unsupported operand type {op!r}") def _compile_charset(charset, flags, code): # compile charset subprogram emit = code.append for op, av in charset: emit(op) if op is NEGATE: pass elif op is LITERAL: emit(av) elif op is RANGE or op is RANGE_UNI_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: emit(CH_UNICODE[av]) else: emit(av) else: raise PatternError(f"internal: unsupported set operator {op!r}") emit(FAILURE) def _optimize_charset(charset, iscased=None, fixup=None, fixes=None): # internal: optimize character set out = [] tail = [] charmap = bytearray(256) hascased = False for op, av in charset: while True: try: if op is LITERAL: if fixup: # IGNORECASE and not LOCALE av = fixup(av) charmap[av] = 1 if fixes and av in fixes: for k in fixes[av]: charmap[k] = 1 if not hascased and iscased(av): hascased = True else: charmap[av] = 1 elif op is RANGE: r = range(av[0], av[1]+1) if fixup: # IGNORECASE and not LOCALE if fixes: for i in map(fixup, r): charmap[i] = 1 if i in fixes: for k in fixes[i]: charmap[k] = 1 else: for i in map(fixup, r): charmap[i] = 1 if not hascased: hascased = any(map(iscased, r)) else: for i in r: charmap[i] = 1 elif op is NEGATE: out.append((op, av)) elif op is CATEGORY and tail and (CATEGORY, CH_NEGATE[av]) in tail: # Optimize [\s\S] etc. out = [] if out else _CHARSET_ALL return out, False 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. # For range, all BMP characters in the range are already # proceeded. if fixup: # IGNORECASE and not LOCALE # For now, IN_UNI_IGNORE+LITERAL and # IN_UNI_IGNORE+RANGE_UNI_IGNORE work for all non-BMP # characters, because two characters (at least one of # which is not in the BMP) match case-insensitively # if and only if: # 1) c1.lower() == c2.lower() # 2) c1.lower() == c2 or c1.lower().upper() == c2 # Also, both c.lower() and c.lower().upper() are single # characters for every non-BMP character. if op is RANGE: if fixes: # not ASCII op = RANGE_UNI_IGNORE hascased = True else: assert op is LITERAL if not hascased and iscased(av): hascased = True 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 hascased or len(out) < len(charset): return out, hascased # else original character set is good enough return charset, hascased # use bitmap if len(charmap) == 256: data = _mk_bitmap(charmap) out.append((CHARSET, data)) out += tail return out, hascased # 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, hascased _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(p): # check if this subpattern is a "simple" operator if len(p) != 1: return False op, av = p[0] if op is SUBPATTERN: return av[0] is None and _simple(av[-1]) return op in _UNIT_CODES 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_iscased(flags): if not flags & SRE_FLAG_IGNORECASE: return None elif flags & SRE_FLAG_UNICODE: return _sre.unicode_iscased else: return _sre.ascii_iscased def _get_literal_prefix(pattern, flags): # look for literal prefix prefix = [] prefixappend = prefix.append prefix_skip = None iscased = _get_iscased(flags) for op, av in pattern.data: if op is LITERAL: if iscased and iscased(av): break prefixappend(av) elif op is SUBPATTERN: group, add_flags, del_flags, p = av flags1 = _combine_flags(flags, add_flags, del_flags) if flags1 & SRE_FLAG_IGNORECASE and flags1 & SRE_FLAG_LOCALE: break prefix1, prefix_skip1, got_all = _get_literal_prefix(p, flags1) 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, flags): while True: if not pattern.data: return None op, av = pattern.data[0] if op is not SUBPATTERN: break group, add_flags, del_flags, pattern = av flags = _combine_flags(flags, add_flags, del_flags) if flags & SRE_FLAG_IGNORECASE and flags & SRE_FLAG_LOCALE: return None iscased = _get_iscased(flags) if op is LITERAL: if iscased and iscased(av): return None return [(op, av)] elif op is BRANCH: charset = [] charsetappend = charset.append for p in av[1]: if not p: return None op, av = p[0] if op is LITERAL and not (iscased and iscased(av)): charsetappend((op, av)) else: return None return charset elif op is IN: charset = av if iscased: for op, av in charset: if op is LITERAL: if iscased(av): return None elif op is RANGE: if av[1] > 0xffff: return None if any(map(iscased, range(av[0], av[1]+1))): return None return charset return None 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 = None # not used if not (flags & SRE_FLAG_IGNORECASE and flags & SRE_FLAG_LOCALE): # look for literal prefix prefix, prefix_skip, got_all = _get_literal_prefix(pattern, flags) # if no prefix, look for charset prefix if not prefix: charset = _get_charset_prefix(pattern, flags) if charset: charset, hascased = _optimize_charset(charset) assert not hascased if charset == _CHARSET_ALL: charset = None ## 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(hi) # 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.state.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 _hex_code(code): return '[%s]' % ', '.join('%#0*x' % (_sre.CODESIZE*2+2, x) for x in code) def dis(code): import sys labels = set() level = 0 offset_width = len(str(len(code) - 1)) def dis_(start, end): def print_(*args, to=None): if to is not None: labels.add(to) args += ('(to %d)' % (to,),) print('%*d%s ' % (offset_width, start, ':' if start in labels else '.'), end=' '*(level-1)) print(*args) def print_2(*args): print(end=' '*(offset_width + 2*level)) print(*args) nonlocal level level += 1 i = start while i < end: start = i op = code[i] i += 1 op = OPCODES[op] if op in (SUCCESS, FAILURE, ANY, ANY_ALL, MAX_UNTIL, MIN_UNTIL, NEGATE): print_(op) elif op in (LITERAL, NOT_LITERAL, LITERAL_IGNORE, NOT_LITERAL_IGNORE, LITERAL_UNI_IGNORE, NOT_LITERAL_UNI_IGNORE, LITERAL_LOC_IGNORE, NOT_LITERAL_LOC_IGNORE): arg = code[i] i += 1 print_(op, '%#02x (%r)' % (arg, chr(arg))) elif op is AT: arg = code[i] i += 1 arg = str(ATCODES[arg]) assert arg[:3] == 'AT_' print_(op, arg[3:]) elif op is CATEGORY: arg = code[i] i += 1 arg = str(CHCODES[arg]) assert arg[:9] == 'CATEGORY_' print_(op, arg[9:]) elif op in (IN, IN_IGNORE, IN_UNI_IGNORE, IN_LOC_IGNORE): skip = code[i] print_(op, skip, to=i+skip) dis_(i+1, i+skip) i += skip elif op in (RANGE, RANGE_UNI_IGNORE): lo, hi = code[i: i+2] i += 2 print_(op, '%#02x %#02x (%r-%r)' % (lo, hi, chr(lo), chr(hi))) elif op is CHARSET: print_(op, _hex_code(code[i: i + 256//_CODEBITS])) i += 256//_CODEBITS elif op is BIGCHARSET: arg = code[i] i += 1 mapping = list(b''.join(x.to_bytes(_sre.CODESIZE, sys.byteorder) for x in code[i: i + 256//_sre.CODESIZE])) print_(op, arg, mapping) i += 256//_sre.CODESIZE level += 1 for j in range(arg): print_2(_hex_code(code[i: i + 256//_CODEBITS])) i += 256//_CODEBITS level -= 1 elif op in (MARK, GROUPREF, GROUPREF_IGNORE, GROUPREF_UNI_IGNORE, GROUPREF_LOC_IGNORE): arg = code[i] i += 1 print_(op, arg) elif op is JUMP: skip = code[i] print_(op, skip, to=i+skip) i += 1 elif op is BRANCH: skip = code[i] print_(op, skip, to=i+skip) while skip: dis_(i+1, i+skip) i += skip start = i skip = code[i] if skip: print_('branch', skip, to=i+skip) else: print_(FAILURE) i += 1 elif op in (REPEAT, REPEAT_ONE, MIN_REPEAT_ONE, POSSESSIVE_REPEAT, POSSESSIVE_REPEAT_ONE): skip, min, max = code[i: i+3] if max == MAXREPEAT: max = 'MAXREPEAT' print_(op, skip, min, max, to=i+skip) dis_(i+3, i+skip) i += skip elif op is GROUPREF_EXISTS: arg, skip = code[i: i+2] print_(op, arg, skip, to=i+skip) i += 2 elif op in (ASSERT, ASSERT_NOT): skip, arg = code[i: i+2] print_(op, skip, arg, to=i+skip) dis_(i+2, i+skip) i += skip elif op is ATOMIC_GROUP: skip = code[i] print_(op, skip, to=i+skip) dis_(i+1, i+skip) i += skip elif op is INFO: skip, flags, min, max = code[i: i+4] if max == MAXREPEAT: max = 'MAXREPEAT' print_(op, skip, bin(flags), min, max, to=i+skip) start = i+4 if flags & SRE_INFO_PREFIX: prefix_len, prefix_skip = code[i+4: i+6] print_2(' prefix_skip', prefix_skip) start = i + 6 prefix = code[start: start+prefix_len] print_2(' prefix', '[%s]' % ', '.join('%#02x' % x for x in prefix), '(%r)' % ''.join(map(chr, prefix))) start += prefix_len print_2(' overlap', code[start: start+prefix_len]) start += prefix_len if flags & SRE_INFO_CHARSET: level += 1 print_2('in') dis_(start, i+skip) level -= 1 i += skip else: raise ValueError(op) level -= 1 dis_(0, len(code)) def compile(p, flags=0): # internal: convert pattern list to internal format if isstring(p): pattern = p p = _parser.parse(p, flags) else: pattern = None code = _code(p, flags) if flags & SRE_FLAG_DEBUG: print() dis(code) # map in either direction groupindex = p.state.groupdict indexgroup = [None] * p.state.groups for k, i in groupindex.items(): indexgroup[i] = k return _sre.compile( pattern, flags | p.state.flags, code, p.state.groups-1, groupindex, tuple(indexgroup) )