1# -*- coding: utf-8 -*-
2#
3# Secret Labs' Regular Expression Engine
4#
5# convert template to internal format
6#
7# Copyright (c) 1997-2001 by Secret Labs AB.  All rights reserved.
8#
9# See the sre.py file for information on usage and redistribution.
10#
11
12"""Internal support module for sre"""
13
14import _sre, sys
15import sre_parse
16from sre_constants import *
17
18assert _sre.MAGIC == MAGIC, "SRE module mismatch"
19
20if _sre.CODESIZE == 2:
21    MAXCODE = 65535
22else:
23    MAXCODE = 0xFFFFFFFFL
24
25_LITERAL_CODES = set([LITERAL, NOT_LITERAL])
26_REPEATING_CODES = set([REPEAT, MIN_REPEAT, MAX_REPEAT])
27_SUCCESS_CODES = set([SUCCESS, FAILURE])
28_ASSERT_CODES = set([ASSERT, ASSERT_NOT])
29
30# Sets of lowercase characters which have the same uppercase.
31_equivalences = (
32    # LATIN SMALL LETTER I, LATIN SMALL LETTER DOTLESS I
33    (0x69, 0x131), # iı
34    # LATIN SMALL LETTER S, LATIN SMALL LETTER LONG S
35    (0x73, 0x17f), # sſ
36    # MICRO SIGN, GREEK SMALL LETTER MU
37    (0xb5, 0x3bc), # µμ
38    # COMBINING GREEK YPOGEGRAMMENI, GREEK SMALL LETTER IOTA, GREEK PROSGEGRAMMENI
39    (0x345, 0x3b9, 0x1fbe), # \u0345ιι
40    # GREEK SMALL LETTER BETA, GREEK BETA SYMBOL
41    (0x3b2, 0x3d0), # βϐ
42    # GREEK SMALL LETTER EPSILON, GREEK LUNATE EPSILON SYMBOL
43    (0x3b5, 0x3f5), # εϵ
44    # GREEK SMALL LETTER THETA, GREEK THETA SYMBOL
45    (0x3b8, 0x3d1), # θϑ
46    # GREEK SMALL LETTER KAPPA, GREEK KAPPA SYMBOL
47    (0x3ba, 0x3f0), # κϰ
48    # GREEK SMALL LETTER PI, GREEK PI SYMBOL
49    (0x3c0, 0x3d6), # πϖ
50    # GREEK SMALL LETTER RHO, GREEK RHO SYMBOL
51    (0x3c1, 0x3f1), # ρϱ
52    # GREEK SMALL LETTER FINAL SIGMA, GREEK SMALL LETTER SIGMA
53    (0x3c2, 0x3c3), # ςσ
54    # GREEK SMALL LETTER PHI, GREEK PHI SYMBOL
55    (0x3c6, 0x3d5), # φϕ
56    # LATIN SMALL LETTER S WITH DOT ABOVE, LATIN SMALL LETTER LONG S WITH DOT ABOVE
57    (0x1e61, 0x1e9b), # ṡẛ
58)
59
60# Maps the lowercase code to lowercase codes which have the same uppercase.
61_ignorecase_fixes = {i: tuple(j for j in t if i != j)
62                     for t in _equivalences for i in t}
63
64def _compile(code, pattern, flags):
65    # internal: compile a (sub)pattern
66    emit = code.append
67    _len = len
68    LITERAL_CODES = _LITERAL_CODES
69    REPEATING_CODES = _REPEATING_CODES
70    SUCCESS_CODES = _SUCCESS_CODES
71    ASSERT_CODES = _ASSERT_CODES
72    if (flags & SRE_FLAG_IGNORECASE and
73            not (flags & SRE_FLAG_LOCALE) and
74            flags & SRE_FLAG_UNICODE):
75        fixes = _ignorecase_fixes
76    else:
77        fixes = None
78    for op, av in pattern:
79        if op in LITERAL_CODES:
80            if flags & SRE_FLAG_IGNORECASE:
81                lo = _sre.getlower(av, flags)
82                if fixes and lo in fixes:
83                    emit(OPCODES[IN_IGNORE])
84                    skip = _len(code); emit(0)
85                    if op is NOT_LITERAL:
86                        emit(OPCODES[NEGATE])
87                    for k in (lo,) + fixes[lo]:
88                        emit(OPCODES[LITERAL])
89                        emit(k)
90                    emit(OPCODES[FAILURE])
91                    code[skip] = _len(code) - skip
92                else:
93                    emit(OPCODES[OP_IGNORE[op]])
94                    emit(lo)
95            else:
96                emit(OPCODES[op])
97                emit(av)
98        elif op is IN:
99            if flags & SRE_FLAG_IGNORECASE:
100                emit(OPCODES[OP_IGNORE[op]])
101                def fixup(literal, flags=flags):
102                    return _sre.getlower(literal, flags)
103            else:
104                emit(OPCODES[op])
105                fixup = None
106            skip = _len(code); emit(0)
107            _compile_charset(av, flags, code, fixup, fixes)
108            code[skip] = _len(code) - skip
109        elif op is ANY:
110            if flags & SRE_FLAG_DOTALL:
111                emit(OPCODES[ANY_ALL])
112            else:
113                emit(OPCODES[ANY])
114        elif op in REPEATING_CODES:
115            if flags & SRE_FLAG_TEMPLATE:
116                raise error, "internal: unsupported template operator"
117                emit(OPCODES[REPEAT])
118                skip = _len(code); emit(0)
119                emit(av[0])
120                emit(av[1])
121                _compile(code, av[2], flags)
122                emit(OPCODES[SUCCESS])
123                code[skip] = _len(code) - skip
124            elif _simple(av) and op is not REPEAT:
125                if op is MAX_REPEAT:
126                    emit(OPCODES[REPEAT_ONE])
127                else:
128                    emit(OPCODES[MIN_REPEAT_ONE])
129                skip = _len(code); emit(0)
130                emit(av[0])
131                emit(av[1])
132                _compile(code, av[2], flags)
133                emit(OPCODES[SUCCESS])
134                code[skip] = _len(code) - skip
135            else:
136                emit(OPCODES[REPEAT])
137                skip = _len(code); emit(0)
138                emit(av[0])
139                emit(av[1])
140                _compile(code, av[2], flags)
141                code[skip] = _len(code) - skip
142                if op is MAX_REPEAT:
143                    emit(OPCODES[MAX_UNTIL])
144                else:
145                    emit(OPCODES[MIN_UNTIL])
146        elif op is SUBPATTERN:
147            if av[0]:
148                emit(OPCODES[MARK])
149                emit((av[0]-1)*2)
150            # _compile_info(code, av[1], flags)
151            _compile(code, av[1], flags)
152            if av[0]:
153                emit(OPCODES[MARK])
154                emit((av[0]-1)*2+1)
155        elif op in SUCCESS_CODES:
156            emit(OPCODES[op])
157        elif op in ASSERT_CODES:
158            emit(OPCODES[op])
159            skip = _len(code); emit(0)
160            if av[0] >= 0:
161                emit(0) # look ahead
162            else:
163                lo, hi = av[1].getwidth()
164                if lo != hi:
165                    raise error, "look-behind requires fixed-width pattern"
166                emit(lo) # look behind
167            _compile(code, av[1], flags)
168            emit(OPCODES[SUCCESS])
169            code[skip] = _len(code) - skip
170        elif op is CALL:
171            emit(OPCODES[op])
172            skip = _len(code); emit(0)
173            _compile(code, av, flags)
174            emit(OPCODES[SUCCESS])
175            code[skip] = _len(code) - skip
176        elif op is AT:
177            emit(OPCODES[op])
178            if flags & SRE_FLAG_MULTILINE:
179                av = AT_MULTILINE.get(av, av)
180            if flags & SRE_FLAG_LOCALE:
181                av = AT_LOCALE.get(av, av)
182            elif flags & SRE_FLAG_UNICODE:
183                av = AT_UNICODE.get(av, av)
184            emit(ATCODES[av])
185        elif op is BRANCH:
186            emit(OPCODES[op])
187            tail = []
188            tailappend = tail.append
189            for av in av[1]:
190                skip = _len(code); emit(0)
191                # _compile_info(code, av, flags)
192                _compile(code, av, flags)
193                emit(OPCODES[JUMP])
194                tailappend(_len(code)); emit(0)
195                code[skip] = _len(code) - skip
196            emit(0) # end of branch
197            for tail in tail:
198                code[tail] = _len(code) - tail
199        elif op is CATEGORY:
200            emit(OPCODES[op])
201            if flags & SRE_FLAG_LOCALE:
202                av = CH_LOCALE[av]
203            elif flags & SRE_FLAG_UNICODE:
204                av = CH_UNICODE[av]
205            emit(CHCODES[av])
206        elif op is GROUPREF:
207            if flags & SRE_FLAG_IGNORECASE:
208                emit(OPCODES[OP_IGNORE[op]])
209            else:
210                emit(OPCODES[op])
211            emit(av-1)
212        elif op is GROUPREF_EXISTS:
213            emit(OPCODES[op])
214            emit(av[0]-1)
215            skipyes = _len(code); emit(0)
216            _compile(code, av[1], flags)
217            if av[2]:
218                emit(OPCODES[JUMP])
219                skipno = _len(code); emit(0)
220                code[skipyes] = _len(code) - skipyes + 1
221                _compile(code, av[2], flags)
222                code[skipno] = _len(code) - skipno
223            else:
224                code[skipyes] = _len(code) - skipyes + 1
225        else:
226            raise ValueError, ("unsupported operand type", op)
227
228def _compile_charset(charset, flags, code, fixup=None, fixes=None):
229    # compile charset subprogram
230    emit = code.append
231    for op, av in _optimize_charset(charset, fixup, fixes,
232                                    flags & SRE_FLAG_UNICODE):
233        emit(OPCODES[op])
234        if op is NEGATE:
235            pass
236        elif op is LITERAL:
237            emit(av)
238        elif op is RANGE:
239            emit(av[0])
240            emit(av[1])
241        elif op is CHARSET:
242            code.extend(av)
243        elif op is BIGCHARSET:
244            code.extend(av)
245        elif op is CATEGORY:
246            if flags & SRE_FLAG_LOCALE:
247                emit(CHCODES[CH_LOCALE[av]])
248            elif flags & SRE_FLAG_UNICODE:
249                emit(CHCODES[CH_UNICODE[av]])
250            else:
251                emit(CHCODES[av])
252        else:
253            raise error, "internal: unsupported set operator"
254    emit(OPCODES[FAILURE])
255
256def _optimize_charset(charset, fixup, fixes, isunicode):
257    # internal: optimize character set
258    out = []
259    tail = []
260    charmap = bytearray(256)
261    for op, av in charset:
262        while True:
263            try:
264                if op is LITERAL:
265                    if fixup:
266                        i = fixup(av)
267                        charmap[i] = 1
268                        if fixes and i in fixes:
269                            for k in fixes[i]:
270                                charmap[k] = 1
271                    else:
272                        charmap[av] = 1
273                elif op is RANGE:
274                    r = range(av[0], av[1]+1)
275                    if fixup:
276                        r = map(fixup, r)
277                    if fixup and fixes:
278                        for i in r:
279                            charmap[i] = 1
280                            if i in fixes:
281                                for k in fixes[i]:
282                                    charmap[k] = 1
283                    else:
284                        for i in r:
285                            charmap[i] = 1
286                elif op is NEGATE:
287                    out.append((op, av))
288                else:
289                    tail.append((op, av))
290            except IndexError:
291                if len(charmap) == 256:
292                    # character set contains non-UCS1 character codes
293                    charmap += b'\0' * 0xff00
294                    continue
295                # character set contains non-BMP character codes
296                if fixup and isunicode and op is RANGE:
297                    lo, hi = av
298                    ranges = [av]
299                    # There are only two ranges of cased astral characters:
300                    # 10400-1044F (Deseret) and 118A0-118DF (Warang Citi).
301                    _fixup_range(max(0x10000, lo), min(0x11fff, hi),
302                                 ranges, fixup)
303                    for lo, hi in ranges:
304                        if lo == hi:
305                            tail.append((LITERAL, hi))
306                        else:
307                            tail.append((RANGE, (lo, hi)))
308                else:
309                    tail.append((op, av))
310            break
311
312    # compress character map
313    runs = []
314    q = 0
315    while True:
316        p = charmap.find(b'\1', q)
317        if p < 0:
318            break
319        if len(runs) >= 2:
320            runs = None
321            break
322        q = charmap.find(b'\0', p)
323        if q < 0:
324            runs.append((p, len(charmap)))
325            break
326        runs.append((p, q))
327    if runs is not None:
328        # use literal/range
329        for p, q in runs:
330            if q - p == 1:
331                out.append((LITERAL, p))
332            else:
333                out.append((RANGE, (p, q - 1)))
334        out += tail
335        # if the case was changed or new representation is more compact
336        if fixup or len(out) < len(charset):
337            return out
338        # else original character set is good enough
339        return charset
340
341    # use bitmap
342    if len(charmap) == 256:
343        data = _mk_bitmap(charmap)
344        out.append((CHARSET, data))
345        out += tail
346        return out
347
348    # To represent a big charset, first a bitmap of all characters in the
349    # set is constructed. Then, this bitmap is sliced into chunks of 256
350    # characters, duplicate chunks are eliminated, and each chunk is
351    # given a number. In the compiled expression, the charset is
352    # represented by a 32-bit word sequence, consisting of one word for
353    # the number of different chunks, a sequence of 256 bytes (64 words)
354    # of chunk numbers indexed by their original chunk position, and a
355    # sequence of 256-bit chunks (8 words each).
356
357    # Compression is normally good: in a typical charset, large ranges of
358    # Unicode will be either completely excluded (e.g. if only cyrillic
359    # letters are to be matched), or completely included (e.g. if large
360    # subranges of Kanji match). These ranges will be represented by
361    # chunks of all one-bits or all zero-bits.
362
363    # Matching can be also done efficiently: the more significant byte of
364    # the Unicode character is an index into the chunk number, and the
365    # less significant byte is a bit index in the chunk (just like the
366    # CHARSET matching).
367
368    # In UCS-4 mode, the BIGCHARSET opcode still supports only subsets
369    # of the basic multilingual plane; an efficient representation
370    # for all of Unicode has not yet been developed.
371
372    charmap = bytes(charmap) # should be hashable
373    comps = {}
374    mapping = bytearray(256)
375    block = 0
376    data = bytearray()
377    for i in range(0, 65536, 256):
378        chunk = charmap[i: i + 256]
379        if chunk in comps:
380            mapping[i // 256] = comps[chunk]
381        else:
382            mapping[i // 256] = comps[chunk] = block
383            block += 1
384            data += chunk
385    data = _mk_bitmap(data)
386    data[0:0] = [block] + _bytes_to_codes(mapping)
387    out.append((BIGCHARSET, data))
388    out += tail
389    return out
390
391def _fixup_range(lo, hi, ranges, fixup):
392    for i in map(fixup, range(lo, hi+1)):
393        for k, (lo, hi) in enumerate(ranges):
394            if i < lo:
395                if l == lo - 1:
396                    ranges[k] = (i, hi)
397                else:
398                    ranges.insert(k, (i, i))
399                break
400            elif i > hi:
401                if i == hi + 1:
402                    ranges[k] = (lo, i)
403                    break
404            else:
405                break
406        else:
407            ranges.append((i, i))
408
409_CODEBITS = _sre.CODESIZE * 8
410_BITS_TRANS = b'0' + b'1' * 255
411def _mk_bitmap(bits, _CODEBITS=_CODEBITS, _int=int):
412    s = bytes(bits).translate(_BITS_TRANS)[::-1]
413    return [_int(s[i - _CODEBITS: i], 2)
414            for i in range(len(s), 0, -_CODEBITS)]
415
416def _bytes_to_codes(b):
417    # Convert block indices to word array
418    import array
419    if _sre.CODESIZE == 2:
420        code = 'H'
421    else:
422        code = 'I'
423    a = array.array(code, bytes(b))
424    assert a.itemsize == _sre.CODESIZE
425    assert len(a) * a.itemsize == len(b)
426    return a.tolist()
427
428def _simple(av):
429    # check if av is a "simple" operator
430    lo, hi = av[2].getwidth()
431    return lo == hi == 1 and av[2][0][0] != SUBPATTERN
432
433def _compile_info(code, pattern, flags):
434    # internal: compile an info block.  in the current version,
435    # this contains min/max pattern width, and an optional literal
436    # prefix or a character map
437    lo, hi = pattern.getwidth()
438    if lo == 0:
439        return # not worth it
440    # look for a literal prefix
441    prefix = []
442    prefixappend = prefix.append
443    prefix_skip = 0
444    charset = [] # not used
445    charsetappend = charset.append
446    if not (flags & SRE_FLAG_IGNORECASE):
447        # look for literal prefix
448        for op, av in pattern.data:
449            if op is LITERAL:
450                if len(prefix) == prefix_skip:
451                    prefix_skip = prefix_skip + 1
452                prefixappend(av)
453            elif op is SUBPATTERN and len(av[1]) == 1:
454                op, av = av[1][0]
455                if op is LITERAL:
456                    prefixappend(av)
457                else:
458                    break
459            else:
460                break
461        # if no prefix, look for charset prefix
462        if not prefix and pattern.data:
463            op, av = pattern.data[0]
464            if op is SUBPATTERN and av[1]:
465                op, av = av[1][0]
466                if op is LITERAL:
467                    charsetappend((op, av))
468                elif op is BRANCH:
469                    c = []
470                    cappend = c.append
471                    for p in av[1]:
472                        if not p:
473                            break
474                        op, av = p[0]
475                        if op is LITERAL:
476                            cappend((op, av))
477                        else:
478                            break
479                    else:
480                        charset = c
481            elif op is BRANCH:
482                c = []
483                cappend = c.append
484                for p in av[1]:
485                    if not p:
486                        break
487                    op, av = p[0]
488                    if op is LITERAL:
489                        cappend((op, av))
490                    else:
491                        break
492                else:
493                    charset = c
494            elif op is IN:
495                charset = av
496##     if prefix:
497##         print "*** PREFIX", prefix, prefix_skip
498##     if charset:
499##         print "*** CHARSET", charset
500    # add an info block
501    emit = code.append
502    emit(OPCODES[INFO])
503    skip = len(code); emit(0)
504    # literal flag
505    mask = 0
506    if prefix:
507        mask = SRE_INFO_PREFIX
508        if len(prefix) == prefix_skip == len(pattern.data):
509            mask = mask + SRE_INFO_LITERAL
510    elif charset:
511        mask = mask + SRE_INFO_CHARSET
512    emit(mask)
513    # pattern length
514    if lo < MAXCODE:
515        emit(lo)
516    else:
517        emit(MAXCODE)
518        prefix = prefix[:MAXCODE]
519    if hi < MAXCODE:
520        emit(hi)
521    else:
522        emit(0)
523    # add literal prefix
524    if prefix:
525        emit(len(prefix)) # length
526        emit(prefix_skip) # skip
527        code.extend(prefix)
528        # generate overlap table
529        table = [-1] + ([0]*len(prefix))
530        for i in xrange(len(prefix)):
531            table[i+1] = table[i]+1
532            while table[i+1] > 0 and prefix[i] != prefix[table[i+1]-1]:
533                table[i+1] = table[table[i+1]-1]+1
534        code.extend(table[1:]) # don't store first entry
535    elif charset:
536        _compile_charset(charset, flags, code)
537    code[skip] = len(code) - skip
538
539try:
540    unicode
541except NameError:
542    STRING_TYPES = (type(""),)
543else:
544    STRING_TYPES = (type(""), type(unicode("")))
545
546def isstring(obj):
547    for tp in STRING_TYPES:
548        if isinstance(obj, tp):
549            return 1
550    return 0
551
552def _code(p, flags):
553
554    flags = p.pattern.flags | flags
555    code = []
556
557    # compile info block
558    _compile_info(code, p, flags)
559
560    # compile the pattern
561    _compile(code, p.data, flags)
562
563    code.append(OPCODES[SUCCESS])
564
565    return code
566
567def compile(p, flags=0):
568    # internal: convert pattern list to internal format
569
570    if isstring(p):
571        pattern = p
572        p = sre_parse.parse(p, flags)
573    else:
574        pattern = None
575
576    code = _code(p, flags)
577
578    # print code
579
580    # XXX: <fl> get rid of this limitation!
581    if p.pattern.groups > 100:
582        raise AssertionError(
583            "sorry, but this version only supports 100 named groups"
584            )
585
586    # map in either direction
587    groupindex = p.pattern.groupdict
588    indexgroup = [None] * p.pattern.groups
589    for k, i in groupindex.items():
590        indexgroup[i] = k
591
592    return _sre.compile(
593        pattern, flags | p.pattern.flags, code,
594        p.pattern.groups-1,
595        groupindex, indexgroup
596        )
597