/[pcre]/code/trunk/pcre_study.c
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revision 91 by nigel, Sat Feb 24 21:41:34 2007 UTC revision 602 by ph10, Wed May 25 08:29:03 2011 UTC
# Line 6  Line 6 
6  and semantics are as close as possible to those of the Perl 5 language.  and semantics are as close as possible to those of the Perl 5 language.
7    
8                         Written by Philip Hazel                         Written by Philip Hazel
9             Copyright (c) 1997-2006 University of Cambridge             Copyright (c) 1997-2010 University of Cambridge
10    
11  -----------------------------------------------------------------------------  -----------------------------------------------------------------------------
12  Redistribution and use in source and binary forms, with or without  Redistribution and use in source and binary forms, with or without
# Line 42  POSSIBILITY OF SUCH DAMAGE. Line 42  POSSIBILITY OF SUCH DAMAGE.
42  supporting functions. */  supporting functions. */
43    
44    
45    #ifdef HAVE_CONFIG_H
46    #include "config.h"
47    #endif
48    
49  #include "pcre_internal.h"  #include "pcre_internal.h"
50    
51    #define SET_BIT(c) start_bits[c/8] |= (1 << (c&7))
52    
53    /* Returns from set_start_bits() */
54    
55    enum { SSB_FAIL, SSB_DONE, SSB_CONTINUE };
56    
57    
58    
59    /*************************************************
60    *   Find the minimum subject length for a group  *
61    *************************************************/
62    
63    /* Scan a parenthesized group and compute the minimum length of subject that
64    is needed to match it. This is a lower bound; it does not mean there is a
65    string of that length that matches. In UTF8 mode, the result is in characters
66    rather than bytes.
67    
68    Arguments:
69      code       pointer to start of group (the bracket)
70      startcode  pointer to start of the whole pattern
71      options    the compiling options
72    
73    Returns:   the minimum length
74               -1 if \C was encountered
75               -2 internal error (missing capturing bracket)
76    */
77    
78    static int
79    find_minlength(const uschar *code, const uschar *startcode, int options)
80    {
81    int length = -1;
82    BOOL utf8 = (options & PCRE_UTF8) != 0;
83    BOOL had_recurse = FALSE;
84    register int branchlength = 0;
85    register uschar *cc = (uschar *)code + 1 + LINK_SIZE;
86    
87    if (*code == OP_CBRA || *code == OP_SCBRA) cc += 2;
88    
89    /* Scan along the opcodes for this branch. If we get to the end of the
90    branch, check the length against that of the other branches. */
91    
92    for (;;)
93      {
94      int d, min;
95      uschar *cs, *ce;
96      register int op = *cc;
97    
98      switch (op)
99        {
100        case OP_COND:
101        case OP_SCOND:
102    
103        /* If there is only one branch in a condition, the implied branch has zero
104        length, so we don't add anything. This covers the DEFINE "condition"
105        automatically. */
106    
107        cs = cc + GET(cc, 1);
108        if (*cs != OP_ALT)
109          {
110          cc = cs + 1 + LINK_SIZE;
111          break;
112          }
113    
114        /* Otherwise we can fall through and treat it the same as any other
115        subpattern. */
116    
117        case OP_CBRA:
118        case OP_SCBRA:
119        case OP_BRA:
120        case OP_SBRA:
121        case OP_ONCE:
122        d = find_minlength(cc, startcode, options);
123        if (d < 0) return d;
124        branchlength += d;
125        do cc += GET(cc, 1); while (*cc == OP_ALT);
126        cc += 1 + LINK_SIZE;
127        break;
128    
129        /* Reached end of a branch; if it's a ket it is the end of a nested
130        call. If it's ALT it is an alternation in a nested call. If it is
131        END it's the end of the outer call. All can be handled by the same code. */
132    
133        case OP_ALT:
134        case OP_KET:
135        case OP_KETRMAX:
136        case OP_KETRMIN:
137        case OP_END:
138        if (length < 0 || (!had_recurse && branchlength < length))
139          length = branchlength;
140        if (*cc != OP_ALT) return length;
141        cc += 1 + LINK_SIZE;
142        branchlength = 0;
143        had_recurse = FALSE;
144        break;
145    
146        /* Skip over assertive subpatterns */
147    
148        case OP_ASSERT:
149        case OP_ASSERT_NOT:
150        case OP_ASSERTBACK:
151        case OP_ASSERTBACK_NOT:
152        do cc += GET(cc, 1); while (*cc == OP_ALT);
153        /* Fall through */
154    
155        /* Skip over things that don't match chars */
156    
157        case OP_REVERSE:
158        case OP_CREF:
159        case OP_NCREF:
160        case OP_RREF:
161        case OP_NRREF:
162        case OP_DEF:
163        case OP_CALLOUT:
164        case OP_SOD:
165        case OP_SOM:
166        case OP_EOD:
167        case OP_EODN:
168        case OP_CIRC:
169        case OP_CIRCM:
170        case OP_DOLL:
171        case OP_DOLLM:
172        case OP_NOT_WORD_BOUNDARY:
173        case OP_WORD_BOUNDARY:
174        cc += _pcre_OP_lengths[*cc];
175        break;
176    
177        /* Skip over a subpattern that has a {0} or {0,x} quantifier */
178    
179        case OP_BRAZERO:
180        case OP_BRAMINZERO:
181        case OP_SKIPZERO:
182        cc += _pcre_OP_lengths[*cc];
183        do cc += GET(cc, 1); while (*cc == OP_ALT);
184        cc += 1 + LINK_SIZE;
185        break;
186    
187        /* Handle literal characters and + repetitions */
188    
189        case OP_CHAR:
190        case OP_CHARI:
191        case OP_NOT:
192        case OP_NOTI:
193        case OP_PLUS:
194        case OP_MINPLUS:
195        case OP_POSPLUS:
196        case OP_NOTPLUS:
197        case OP_NOTMINPLUS:
198        case OP_NOTPOSPLUS:
199        branchlength++;
200        cc += 2;
201    #ifdef SUPPORT_UTF8
202        if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
203    #endif
204        break;
205    
206        case OP_TYPEPLUS:
207        case OP_TYPEMINPLUS:
208        case OP_TYPEPOSPLUS:
209        branchlength++;
210        cc += (cc[1] == OP_PROP || cc[1] == OP_NOTPROP)? 4 : 2;
211        break;
212    
213        /* Handle exact repetitions. The count is already in characters, but we
214        need to skip over a multibyte character in UTF8 mode.  */
215    
216        case OP_EXACT:
217        case OP_NOTEXACT:
218        branchlength += GET2(cc,1);
219        cc += 4;
220    #ifdef SUPPORT_UTF8
221        if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
222    #endif
223        break;
224    
225        case OP_TYPEEXACT:
226        branchlength += GET2(cc,1);
227        cc += (cc[3] == OP_PROP || cc[3] == OP_NOTPROP)? 6 : 4;
228        break;
229    
230        /* Handle single-char non-literal matchers */
231    
232        case OP_PROP:
233        case OP_NOTPROP:
234        cc += 2;
235        /* Fall through */
236    
237        case OP_NOT_DIGIT:
238        case OP_DIGIT:
239        case OP_NOT_WHITESPACE:
240        case OP_WHITESPACE:
241        case OP_NOT_WORDCHAR:
242        case OP_WORDCHAR:
243        case OP_ANY:
244        case OP_ALLANY:
245        case OP_EXTUNI:
246        case OP_HSPACE:
247        case OP_NOT_HSPACE:
248        case OP_VSPACE:
249        case OP_NOT_VSPACE:
250        branchlength++;
251        cc++;
252        break;
253    
254        /* "Any newline" might match two characters */
255    
256        case OP_ANYNL:
257        branchlength += 2;
258        cc++;
259        break;
260    
261        /* The single-byte matcher means we can't proceed in UTF-8 mode */
262    
263        case OP_ANYBYTE:
264    #ifdef SUPPORT_UTF8
265        if (utf8) return -1;
266    #endif
267        branchlength++;
268        cc++;
269        break;
270    
271        /* For repeated character types, we have to test for \p and \P, which have
272        an extra two bytes of parameters. */
273    
274        case OP_TYPESTAR:
275        case OP_TYPEMINSTAR:
276        case OP_TYPEQUERY:
277        case OP_TYPEMINQUERY:
278        case OP_TYPEPOSSTAR:
279        case OP_TYPEPOSQUERY:
280        if (cc[1] == OP_PROP || cc[1] == OP_NOTPROP) cc += 2;
281        cc += _pcre_OP_lengths[op];
282        break;
283    
284        case OP_TYPEUPTO:
285        case OP_TYPEMINUPTO:
286        case OP_TYPEPOSUPTO:
287        if (cc[3] == OP_PROP || cc[3] == OP_NOTPROP) cc += 2;
288        cc += _pcre_OP_lengths[op];
289        break;
290    
291        /* Check a class for variable quantification */
292    
293    #ifdef SUPPORT_UTF8
294        case OP_XCLASS:
295        cc += GET(cc, 1) - 33;
296        /* Fall through */
297    #endif
298    
299        case OP_CLASS:
300        case OP_NCLASS:
301        cc += 33;
302    
303        switch (*cc)
304          {
305          case OP_CRPLUS:
306          case OP_CRMINPLUS:
307          branchlength++;
308          /* Fall through */
309    
310          case OP_CRSTAR:
311          case OP_CRMINSTAR:
312          case OP_CRQUERY:
313          case OP_CRMINQUERY:
314          cc++;
315          break;
316    
317          case OP_CRRANGE:
318          case OP_CRMINRANGE:
319          branchlength += GET2(cc,1);
320          cc += 5;
321          break;
322    
323          default:
324          branchlength++;
325          break;
326          }
327        break;
328    
329        /* Backreferences and subroutine calls are treated in the same way: we find
330        the minimum length for the subpattern. A recursion, however, causes an
331        a flag to be set that causes the length of this branch to be ignored. The
332        logic is that a recursion can only make sense if there is another
333        alternation that stops the recursing. That will provide the minimum length
334        (when no recursion happens). A backreference within the group that it is
335        referencing behaves in the same way.
336    
337        If PCRE_JAVASCRIPT_COMPAT is set, a backreference to an unset bracket
338        matches an empty string (by default it causes a matching failure), so in
339        that case we must set the minimum length to zero. */
340    
341        case OP_REF:
342        case OP_REFI:
343        if ((options & PCRE_JAVASCRIPT_COMPAT) == 0)
344          {
345          ce = cs = (uschar *)_pcre_find_bracket(startcode, utf8, GET2(cc, 1));
346          if (cs == NULL) return -2;
347          do ce += GET(ce, 1); while (*ce == OP_ALT);
348          if (cc > cs && cc < ce)
349            {
350            d = 0;
351            had_recurse = TRUE;
352            }
353          else d = find_minlength(cs, startcode, options);
354          }
355        else d = 0;
356        cc += 3;
357    
358        /* Handle repeated back references */
359    
360        switch (*cc)
361          {
362          case OP_CRSTAR:
363          case OP_CRMINSTAR:
364          case OP_CRQUERY:
365          case OP_CRMINQUERY:
366          min = 0;
367          cc++;
368          break;
369    
370          case OP_CRRANGE:
371          case OP_CRMINRANGE:
372          min = GET2(cc, 1);
373          cc += 5;
374          break;
375    
376          default:
377          min = 1;
378          break;
379          }
380    
381        branchlength += min * d;
382        break;
383    
384        case OP_RECURSE:
385        cs = ce = (uschar *)startcode + GET(cc, 1);
386        if (cs == NULL) return -2;
387        do ce += GET(ce, 1); while (*ce == OP_ALT);
388        if (cc > cs && cc < ce)
389          had_recurse = TRUE;
390        else
391          branchlength += find_minlength(cs, startcode, options);
392        cc += 1 + LINK_SIZE;
393        break;
394    
395        /* Anything else does not or need not match a character. We can get the
396        item's length from the table, but for those that can match zero occurrences
397        of a character, we must take special action for UTF-8 characters. As it
398        happens, the "NOT" versions of these opcodes are used at present only for
399        ASCII characters, so they could be omitted from this list. However, in
400        future that may change, so we leave them in this special case. */
401    
402        case OP_UPTO:
403        case OP_UPTOI:
404        case OP_NOTUPTO:
405        case OP_NOTUPTOI:
406        case OP_MINUPTO:
407        case OP_MINUPTOI:
408        case OP_NOTMINUPTO:
409        case OP_NOTMINUPTOI:
410        case OP_POSUPTO:
411        case OP_POSUPTOI:
412        case OP_NOTPOSUPTO:
413        case OP_NOTPOSUPTOI:
414    
415        case OP_STAR:
416        case OP_STARI:
417        case OP_NOTSTAR:
418        case OP_NOTSTARI:
419        case OP_MINSTAR:
420        case OP_MINSTARI:
421        case OP_NOTMINSTAR:
422        case OP_NOTMINSTARI:
423        case OP_POSSTAR:
424        case OP_POSSTARI:
425        case OP_NOTPOSSTAR:
426        case OP_NOTPOSSTARI:
427    
428        case OP_QUERY:
429        case OP_QUERYI:
430        case OP_NOTQUERY:
431        case OP_NOTQUERYI:
432        case OP_MINQUERY:
433        case OP_MINQUERYI:
434        case OP_NOTMINQUERY:
435        case OP_NOTMINQUERYI:
436        case OP_POSQUERY:
437        case OP_POSQUERYI:
438        case OP_NOTPOSQUERY:
439        case OP_NOTPOSQUERYI:
440    
441        cc += _pcre_OP_lengths[op];
442    #ifdef SUPPORT_UTF8
443        if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
444    #endif
445        break;
446    
447        /* Skip these, but we need to add in the name length. */
448    
449        case OP_MARK:
450        case OP_PRUNE_ARG:
451        case OP_SKIP_ARG:
452        cc += _pcre_OP_lengths[op] + cc[1];
453        break;
454    
455        case OP_THEN_ARG:
456        cc += _pcre_OP_lengths[op] + cc[1+LINK_SIZE];
457        break;
458    
459        /* For the record, these are the opcodes that are matched by "default":
460        OP_ACCEPT, OP_CLOSE, OP_COMMIT, OP_FAIL, OP_PRUNE, OP_SET_SOM, OP_SKIP,
461        OP_THEN. */
462    
463        default:
464        cc += _pcre_OP_lengths[op];
465        break;
466        }
467      }
468    /* Control never gets here */
469    }
470    
471    
472    
473  /*************************************************  /*************************************************
474  *      Set a bit and maybe its alternate case    *  *      Set a bit and maybe its alternate case    *
475  *************************************************/  *************************************************/
476    
477  /* Given a character, set its bit in the table, and also the bit for the other  /* Given a character, set its first byte's bit in the table, and also the
478  version of a letter if we are caseless.  corresponding bit for the other version of a letter if we are caseless. In
479    UTF-8 mode, for characters greater than 127, we can only do the caseless thing
480    when Unicode property support is available.
481    
482  Arguments:  Arguments:
483    start_bits    points to the bit map    start_bits    points to the bit map
484    c             is the character    p             points to the character
485    caseless      the caseless flag    caseless      the caseless flag
486    cd            the block with char table pointers    cd            the block with char table pointers
487      utf8          TRUE for UTF-8 mode
488    
489    Returns:        pointer after the character
490    */
491    
492    static const uschar *
493    set_table_bit(uschar *start_bits, const uschar *p, BOOL caseless,
494      compile_data *cd, BOOL utf8)
495    {
496    unsigned int c = *p;
497    
498    SET_BIT(c);
499    
500    #ifdef SUPPORT_UTF8
501    if (utf8 && c > 127)
502      {
503      GETCHARINC(c, p);
504    #ifdef SUPPORT_UCP
505      if (caseless)
506        {
507        uschar buff[8];
508        c = UCD_OTHERCASE(c);
509        (void)_pcre_ord2utf8(c, buff);
510        SET_BIT(buff[0]);
511        }
512    #endif
513      return p;
514      }
515    #endif
516    
517    /* Not UTF-8 mode, or character is less than 127. */
518    
519    if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
520    return p + 1;
521    }
522    
523  Returns:        nothing  
524    
525    /*************************************************
526    *     Set bits for a positive character type     *
527    *************************************************/
528    
529    /* This function sets starting bits for a character type. In UTF-8 mode, we can
530    only do a direct setting for bytes less than 128, as otherwise there can be
531    confusion with bytes in the middle of UTF-8 characters. In a "traditional"
532    environment, the tables will only recognize ASCII characters anyway, but in at
533    least one Windows environment, some higher bytes bits were set in the tables.
534    So we deal with that case by considering the UTF-8 encoding.
535    
536    Arguments:
537      start_bits     the starting bitmap
538      cbit type      the type of character wanted
539      table_limit    32 for non-UTF-8; 16 for UTF-8
540      cd             the block with char table pointers
541    
542    Returns:         nothing
543  */  */
544    
545  static void  static void
546  set_bit(uschar *start_bits, unsigned int c, BOOL caseless, compile_data *cd)  set_type_bits(uschar *start_bits, int cbit_type, int table_limit,
547      compile_data *cd)
548  {  {
549  start_bits[c/8] |= (1 << (c&7));  register int c;
550  if (caseless && (cd->ctypes[c] & ctype_letter) != 0)  for (c = 0; c < table_limit; c++) start_bits[c] |= cd->cbits[c+cbit_type];
551    start_bits[cd->fcc[c]/8] |= (1 << (cd->fcc[c]&7));  if (table_limit == 32) return;
552    for (c = 128; c < 256; c++)
553      {
554      if ((cd->cbits[c/8] & (1 << (c&7))) != 0)
555        {
556        uschar buff[8];
557        (void)_pcre_ord2utf8(c, buff);
558        SET_BIT(buff[0]);
559        }
560      }
561    }
562    
563    
564    /*************************************************
565    *     Set bits for a negative character type     *
566    *************************************************/
567    
568    /* This function sets starting bits for a negative character type such as \D.
569    In UTF-8 mode, we can only do a direct setting for bytes less than 128, as
570    otherwise there can be confusion with bytes in the middle of UTF-8 characters.
571    Unlike in the positive case, where we can set appropriate starting bits for
572    specific high-valued UTF-8 characters, in this case we have to set the bits for
573    all high-valued characters. The lowest is 0xc2, but we overkill by starting at
574    0xc0 (192) for simplicity.
575    
576    Arguments:
577      start_bits     the starting bitmap
578      cbit type      the type of character wanted
579      table_limit    32 for non-UTF-8; 16 for UTF-8
580      cd             the block with char table pointers
581    
582    Returns:         nothing
583    */
584    
585    static void
586    set_nottype_bits(uschar *start_bits, int cbit_type, int table_limit,
587      compile_data *cd)
588    {
589    register int c;
590    for (c = 0; c < table_limit; c++) start_bits[c] |= ~cd->cbits[c+cbit_type];
591    if (table_limit != 32) for (c = 24; c < 32; c++) start_bits[c] = 0xff;
592  }  }
593    
594    
595    
596  /*************************************************  /*************************************************
597  *          Create bitmap of starting chars       *  *          Create bitmap of starting bytes       *
598  *************************************************/  *************************************************/
599    
600  /* This function scans a compiled unanchored expression and attempts to build a  /* This function scans a compiled unanchored expression recursively and
601  bitmap of the set of initial characters. If it can't, it returns FALSE. As time  attempts to build a bitmap of the set of possible starting bytes. As time goes
602  goes by, we may be able to get more clever at doing this.  by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
603    useful for parenthesized groups in patterns such as (a*)b where the group
604    provides some optional starting bytes but scanning must continue at the outer
605    level to find at least one mandatory byte. At the outermost level, this
606    function fails unless the result is SSB_DONE.
607    
608  Arguments:  Arguments:
609    code         points to an expression    code         points to an expression
# Line 86  Arguments: Line 612  Arguments:
612    utf8         TRUE if in UTF-8 mode    utf8         TRUE if in UTF-8 mode
613    cd           the block with char table pointers    cd           the block with char table pointers
614    
615  Returns:       TRUE if table built, FALSE otherwise  Returns:       SSB_FAIL     => Failed to find any starting bytes
616                   SSB_DONE     => Found mandatory starting bytes
617                   SSB_CONTINUE => Found optional starting bytes
618  */  */
619    
620  static BOOL  static int
621  set_start_bits(const uschar *code, uschar *start_bits, BOOL caseless,  set_start_bits(const uschar *code, uschar *start_bits, BOOL caseless,
622    BOOL utf8, compile_data *cd)    BOOL utf8, compile_data *cd)
623  {  {
624  register int c;  register int c;
625    int yield = SSB_DONE;
626    int table_limit = utf8? 16:32;
627    
628  #if 0  #if 0
629  /* ========================================================================= */  /* ========================================================================= */
# Line 114  volatile int dummy; Line 644  volatile int dummy;
644    
645  do  do
646    {    {
647    const uschar *tcode = code + 1 + LINK_SIZE;    const uschar *tcode = code + (((int)*code == OP_CBRA)? 3:1) + LINK_SIZE;
648    BOOL try_next = TRUE;    BOOL try_next = TRUE;
649    
650    while (try_next)    while (try_next)    /* Loop for items in this branch */
651      {      {
652      /* If a branch starts with a bracket or a positive lookahead assertion,      int rc;
653      recurse to set bits from within them. That's all for this branch. */      switch(*tcode)
   
     if ((int)*tcode >= OP_BRA || *tcode == OP_ASSERT)  
654        {        {
655        if (!set_start_bits(tcode, start_bits, caseless, utf8, cd))        /* Fail if we reach something we don't understand */
         return FALSE;  
       try_next = FALSE;  
       }  
656    
     else switch(*tcode)  
       {  
657        default:        default:
658        return FALSE;        return SSB_FAIL;
659    
660        /* Skip over callout */        /* If we hit a bracket or a positive lookahead assertion, recurse to set
661          bits from within the subpattern. If it can't find anything, we have to
662          give up. If it finds some mandatory character(s), we are done for this
663          branch. Otherwise, carry on scanning after the subpattern. */
664    
665          case OP_BRA:
666          case OP_SBRA:
667          case OP_CBRA:
668          case OP_SCBRA:
669          case OP_ONCE:
670          case OP_ASSERT:
671          rc = set_start_bits(tcode, start_bits, caseless, utf8, cd);
672          if (rc == SSB_FAIL) return SSB_FAIL;
673          if (rc == SSB_DONE) try_next = FALSE; else
674            {
675            do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
676            tcode += 1 + LINK_SIZE;
677            }
678          break;
679    
680        case OP_CALLOUT:        /* If we hit ALT or KET, it means we haven't found anything mandatory in
681        tcode += 2 + 2*LINK_SIZE;        this branch, though we might have found something optional. For ALT, we
682          continue with the next alternative, but we have to arrange that the final
683          result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
684          return SSB_CONTINUE: if this is the top level, that indicates failure,
685          but after a nested subpattern, it causes scanning to continue. */
686    
687          case OP_ALT:
688          yield = SSB_CONTINUE;
689          try_next = FALSE;
690        break;        break;
691    
692        /* Skip over extended extraction bracket number */        case OP_KET:
693          case OP_KETRMAX:
694          case OP_KETRMIN:
695          return SSB_CONTINUE;
696    
697        case OP_BRANUMBER:        /* Skip over callout */
698        tcode += 3;  
699          case OP_CALLOUT:
700          tcode += 2 + 2*LINK_SIZE;
701        break;        break;
702    
703        /* Skip over lookbehind and negative lookahead assertions */        /* Skip over lookbehind and negative lookahead assertions */
# Line 152  do Line 706  do
706        case OP_ASSERTBACK:        case OP_ASSERTBACK:
707        case OP_ASSERTBACK_NOT:        case OP_ASSERTBACK_NOT:
708        do tcode += GET(tcode, 1); while (*tcode == OP_ALT);        do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
709        tcode += 1+LINK_SIZE;        tcode += 1 + LINK_SIZE;
       break;  
   
       /* Skip over an option setting, changing the caseless flag */  
   
       case OP_OPT:  
       caseless = (tcode[1] & PCRE_CASELESS) != 0;  
       tcode += 2;  
710        break;        break;
711    
712        /* BRAZERO does the bracket, but carries on. */        /* BRAZERO does the bracket, but carries on. */
713    
714        case OP_BRAZERO:        case OP_BRAZERO:
715        case OP_BRAMINZERO:        case OP_BRAMINZERO:
716        if (!set_start_bits(++tcode, start_bits, caseless, utf8, cd))        if (set_start_bits(++tcode, start_bits, caseless, utf8, cd) == SSB_FAIL)
717          return FALSE;          return SSB_FAIL;
718  /* =========================================================================  /* =========================================================================
719        See the comment at the head of this function concerning the next line,        See the comment at the head of this function concerning the next line,
720        which was an old fudge for the benefit of OS/2.        which was an old fudge for the benefit of OS/2.
721        dummy = 1;        dummy = 1;
722    ========================================================================= */    ========================================================================= */
723        do tcode += GET(tcode,1); while (*tcode == OP_ALT);        do tcode += GET(tcode,1); while (*tcode == OP_ALT);
724        tcode += 1+LINK_SIZE;        tcode += 1 + LINK_SIZE;
725          break;
726    
727          /* SKIPZERO skips the bracket. */
728    
729          case OP_SKIPZERO:
730          tcode++;
731          do tcode += GET(tcode,1); while (*tcode == OP_ALT);
732          tcode += 1 + LINK_SIZE;
733        break;        break;
734    
735        /* Single-char * or ? sets the bit and tries the next item */        /* Single-char * or ? sets the bit and tries the next item */
736    
737        case OP_STAR:        case OP_STAR:
738        case OP_MINSTAR:        case OP_MINSTAR:
739          case OP_POSSTAR:
740        case OP_QUERY:        case OP_QUERY:
741        case OP_MINQUERY:        case OP_MINQUERY:
742        set_bit(start_bits, tcode[1], caseless, cd);        case OP_POSQUERY:
743        tcode += 2;        tcode = set_table_bit(start_bits, tcode + 1, caseless, cd, utf8);
744  #ifdef SUPPORT_UTF8        break;
745        if (utf8) while ((*tcode & 0xc0) == 0x80) tcode++;  
746  #endif        case OP_STARI:
747          case OP_MINSTARI:
748          case OP_POSSTARI:
749          case OP_QUERYI:
750          case OP_MINQUERYI:
751          case OP_POSQUERYI:
752          tcode = set_table_bit(start_bits, tcode + 1, TRUE, cd, utf8);
753        break;        break;
754    
755        /* Single-char upto sets the bit and tries the next */        /* Single-char upto sets the bit and tries the next */
756    
757        case OP_UPTO:        case OP_UPTO:
758        case OP_MINUPTO:        case OP_MINUPTO:
759        set_bit(start_bits, tcode[3], caseless, cd);        case OP_POSUPTO:
760        tcode += 4;        tcode = set_table_bit(start_bits, tcode + 3, caseless, cd, utf8);
761  #ifdef SUPPORT_UTF8        break;
762        if (utf8) while ((*tcode & 0xc0) == 0x80) tcode++;  
763  #endif        case OP_UPTOI:
764          case OP_MINUPTOI:
765          case OP_POSUPTOI:
766          tcode = set_table_bit(start_bits, tcode + 3, TRUE, cd, utf8);
767        break;        break;
768    
769        /* At least one single char sets the bit and stops */        /* At least one single char sets the bit and stops */
770    
771        case OP_EXACT:       /* Fall through */        case OP_EXACT:
772        tcode += 2;        tcode += 2;
773          /* Fall through */
774        case OP_CHAR:        case OP_CHAR:
       case OP_CHARNC:  
775        case OP_PLUS:        case OP_PLUS:
776        case OP_MINPLUS:        case OP_MINPLUS:
777        set_bit(start_bits, tcode[1], caseless, cd);        case OP_POSPLUS:
778          (void)set_table_bit(start_bits, tcode + 1, caseless, cd, utf8);
779          try_next = FALSE;
780          break;
781    
782          case OP_CHARI:
783          case OP_PLUSI:
784          case OP_MINPLUSI:
785          case OP_POSPLUSI:
786          (void)set_table_bit(start_bits, tcode + 1, TRUE, cd, utf8);
787          try_next = FALSE;
788          break;
789    
790          /* Special spacing and line-terminating items. These recognize specific
791          lists of characters. The difference between VSPACE and ANYNL is that the
792          latter can match the two-character CRLF sequence, but that is not
793          relevant for finding the first character, so their code here is
794          identical. */
795    
796          case OP_HSPACE:
797          SET_BIT(0x09);
798          SET_BIT(0x20);
799          if (utf8)
800            {
801            SET_BIT(0xC2);  /* For U+00A0 */
802            SET_BIT(0xE1);  /* For U+1680, U+180E */
803            SET_BIT(0xE2);  /* For U+2000 - U+200A, U+202F, U+205F */
804            SET_BIT(0xE3);  /* For U+3000 */
805            }
806          else SET_BIT(0xA0);
807          try_next = FALSE;
808          break;
809    
810          case OP_ANYNL:
811          case OP_VSPACE:
812          SET_BIT(0x0A);
813          SET_BIT(0x0B);
814          SET_BIT(0x0C);
815          SET_BIT(0x0D);
816          if (utf8)
817            {
818            SET_BIT(0xC2);  /* For U+0085 */
819            SET_BIT(0xE2);  /* For U+2028, U+2029 */
820            }
821          else SET_BIT(0x85);
822        try_next = FALSE;        try_next = FALSE;
823        break;        break;
824    
825        /* Single character type sets the bits and stops */        /* Single character types set the bits and stop. Note that if PCRE_UCP
826          is set, we do not see these op codes because \d etc are converted to
827          properties. Therefore, these apply in the case when only characters less
828          than 256 are recognized to match the types. */
829    
830        case OP_NOT_DIGIT:        case OP_NOT_DIGIT:
831        for (c = 0; c < 32; c++)        set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
         start_bits[c] |= ~cd->cbits[c+cbit_digit];  
832        try_next = FALSE;        try_next = FALSE;
833        break;        break;
834    
835        case OP_DIGIT:        case OP_DIGIT:
836        for (c = 0; c < 32; c++)        set_type_bits(start_bits, cbit_digit, table_limit, cd);
         start_bits[c] |= cd->cbits[c+cbit_digit];  
837        try_next = FALSE;        try_next = FALSE;
838        break;        break;
839    
840        /* The cbit_space table has vertical tab as whitespace; we have to        /* The cbit_space table has vertical tab as whitespace; we have to
841        discard it. */        ensure it is set as not whitespace. */
842    
843        case OP_NOT_WHITESPACE:        case OP_NOT_WHITESPACE:
844        for (c = 0; c < 32; c++)        set_nottype_bits(start_bits, cbit_space, table_limit, cd);
845          {        start_bits[1] |= 0x08;
         int d = cd->cbits[c+cbit_space];  
         if (c == 1) d &= ~0x08;  
         start_bits[c] |= ~d;  
         }  
846        try_next = FALSE;        try_next = FALSE;
847        break;        break;
848    
849        /* The cbit_space table has vertical tab as whitespace; we have to        /* The cbit_space table has vertical tab as whitespace; we have to
850        discard it. */        not set it from the table. */
851    
852        case OP_WHITESPACE:        case OP_WHITESPACE:
853        for (c = 0; c < 32; c++)        c = start_bits[1];    /* Save in case it was already set */
854          {        set_type_bits(start_bits, cbit_space, table_limit, cd);
855          int d = cd->cbits[c+cbit_space];        start_bits[1] = (start_bits[1] & ~0x08) | c;
         if (c == 1) d &= ~0x08;  
         start_bits[c] |= d;  
         }  
856        try_next = FALSE;        try_next = FALSE;
857        break;        break;
858    
859        case OP_NOT_WORDCHAR:        case OP_NOT_WORDCHAR:
860        for (c = 0; c < 32; c++)        set_nottype_bits(start_bits, cbit_word, table_limit, cd);
         start_bits[c] |= ~cd->cbits[c+cbit_word];  
861        try_next = FALSE;        try_next = FALSE;
862        break;        break;
863    
864        case OP_WORDCHAR:        case OP_WORDCHAR:
865        for (c = 0; c < 32; c++)        set_type_bits(start_bits, cbit_word, table_limit, cd);
         start_bits[c] |= cd->cbits[c+cbit_word];  
866        try_next = FALSE;        try_next = FALSE;
867        break;        break;
868    
# Line 271  do Line 871  do
871    
872        case OP_TYPEPLUS:        case OP_TYPEPLUS:
873        case OP_TYPEMINPLUS:        case OP_TYPEMINPLUS:
874          case OP_TYPEPOSPLUS:
875        tcode++;        tcode++;
876        break;        break;
877    
# Line 283  do Line 884  do
884    
885        case OP_TYPEUPTO:        case OP_TYPEUPTO:
886        case OP_TYPEMINUPTO:        case OP_TYPEMINUPTO:
887          case OP_TYPEPOSUPTO:
888        tcode += 2;               /* Fall through */        tcode += 2;               /* Fall through */
889    
890        case OP_TYPESTAR:        case OP_TYPESTAR:
891        case OP_TYPEMINSTAR:        case OP_TYPEMINSTAR:
892          case OP_TYPEPOSSTAR:
893        case OP_TYPEQUERY:        case OP_TYPEQUERY:
894        case OP_TYPEMINQUERY:        case OP_TYPEMINQUERY:
895          case OP_TYPEPOSQUERY:
896        switch(tcode[1])        switch(tcode[1])
897          {          {
898            default:
899          case OP_ANY:          case OP_ANY:
900          return FALSE;          case OP_ALLANY:
901            return SSB_FAIL;
902    
903            case OP_HSPACE:
904            SET_BIT(0x09);
905            SET_BIT(0x20);
906            if (utf8)
907              {
908              SET_BIT(0xC2);  /* For U+00A0 */
909              SET_BIT(0xE1);  /* For U+1680, U+180E */
910              SET_BIT(0xE2);  /* For U+2000 - U+200A, U+202F, U+205F */
911              SET_BIT(0xE3);  /* For U+3000 */
912              }
913            else SET_BIT(0xA0);
914            break;
915    
916            case OP_ANYNL:
917            case OP_VSPACE:
918            SET_BIT(0x0A);
919            SET_BIT(0x0B);
920            SET_BIT(0x0C);
921            SET_BIT(0x0D);
922            if (utf8)
923              {
924              SET_BIT(0xC2);  /* For U+0085 */
925              SET_BIT(0xE2);  /* For U+2028, U+2029 */
926              }
927            else SET_BIT(0x85);
928            break;
929    
930          case OP_NOT_DIGIT:          case OP_NOT_DIGIT:
931          for (c = 0; c < 32; c++)          set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
           start_bits[c] |= ~cd->cbits[c+cbit_digit];  
932          break;          break;
933    
934          case OP_DIGIT:          case OP_DIGIT:
935          for (c = 0; c < 32; c++)          set_type_bits(start_bits, cbit_digit, table_limit, cd);
           start_bits[c] |= cd->cbits[c+cbit_digit];  
936          break;          break;
937    
938          /* The cbit_space table has vertical tab as whitespace; we have to          /* The cbit_space table has vertical tab as whitespace; we have to
939          discard it. */          ensure it gets set as not whitespace. */
940    
941          case OP_NOT_WHITESPACE:          case OP_NOT_WHITESPACE:
942          for (c = 0; c < 32; c++)          set_nottype_bits(start_bits, cbit_space, table_limit, cd);
943            {          start_bits[1] |= 0x08;
           int d = cd->cbits[c+cbit_space];  
           if (c == 1) d &= ~0x08;  
           start_bits[c] |= ~d;  
           }  
944          break;          break;
945    
946          /* The cbit_space table has vertical tab as whitespace; we have to          /* The cbit_space table has vertical tab as whitespace; we have to
947          discard it. */          avoid setting it. */
948    
949          case OP_WHITESPACE:          case OP_WHITESPACE:
950          for (c = 0; c < 32; c++)          c = start_bits[1];    /* Save in case it was already set */
951            {          set_type_bits(start_bits, cbit_space, table_limit, cd);
952            int d = cd->cbits[c+cbit_space];          start_bits[1] = (start_bits[1] & ~0x08) | c;
           if (c == 1) d &= ~0x08;  
           start_bits[c] |= d;  
           }  
953          break;          break;
954    
955          case OP_NOT_WORDCHAR:          case OP_NOT_WORDCHAR:
956          for (c = 0; c < 32; c++)          set_nottype_bits(start_bits, cbit_word, table_limit, cd);
           start_bits[c] |= ~cd->cbits[c+cbit_word];  
957          break;          break;
958    
959          case OP_WORDCHAR:          case OP_WORDCHAR:
960          for (c = 0; c < 32; c++)          set_type_bits(start_bits, cbit_word, table_limit, cd);
           start_bits[c] |= cd->cbits[c+cbit_word];  
961          break;          break;
962          }          }
963    
# Line 349  do Line 971  do
971        character with a value > 255. */        character with a value > 255. */
972    
973        case OP_NCLASS:        case OP_NCLASS:
974    #ifdef SUPPORT_UTF8
975        if (utf8)        if (utf8)
976          {          {
977          start_bits[24] |= 0xf0;              /* Bits for 0xc4 - 0xc8 */          start_bits[24] |= 0xf0;              /* Bits for 0xc4 - 0xc8 */
978          memset(start_bits+25, 0xff, 7);      /* Bits for 0xc9 - 0xff */          memset(start_bits+25, 0xff, 7);      /* Bits for 0xc9 - 0xff */
979          }          }
980    #endif
981        /* Fall through */        /* Fall through */
982    
983        case OP_CLASS:        case OP_CLASS:
# Line 366  do Line 990  do
990          value is > 127. In fact, there are only two possible starting bytes for          value is > 127. In fact, there are only two possible starting bytes for
991          characters in the range 128 - 255. */          characters in the range 128 - 255. */
992    
993    #ifdef SUPPORT_UTF8
994          if (utf8)          if (utf8)
995            {            {
996            for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];            for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
# Line 383  do Line 1008  do
1008          /* In non-UTF-8 mode, the two bit maps are completely compatible. */          /* In non-UTF-8 mode, the two bit maps are completely compatible. */
1009    
1010          else          else
1011    #endif
1012            {            {
1013            for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];            for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
1014            }            }
# Line 418  do Line 1044  do
1044    code += GET(code, 1);   /* Advance to next branch */    code += GET(code, 1);   /* Advance to next branch */
1045    }    }
1046  while (*code == OP_ALT);  while (*code == OP_ALT);
1047  return TRUE;  return yield;
1048  }  }
1049    
1050    
# Line 438  Arguments: Line 1064  Arguments:
1064              set NULL unless error              set NULL unless error
1065    
1066  Returns:    pointer to a pcre_extra block, with study_data filled in and the  Returns:    pointer to a pcre_extra block, with study_data filled in and the
1067                appropriate flag set;                appropriate flags set;
1068              NULL on error or if no optimization possible              NULL on error or if no optimization possible
1069  */  */
1070    
1071  PCRE_DATA_SCOPE pcre_extra *  PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
1072  pcre_study(const pcre *external_re, int options, const char **errorptr)  pcre_study(const pcre *external_re, int options, const char **errorptr)
1073  {  {
1074    int min;
1075    BOOL bits_set = FALSE;
1076  uschar start_bits[32];  uschar start_bits[32];
1077  pcre_extra *extra;  pcre_extra *extra;
1078  pcre_study_data *study;  pcre_study_data *study;
# Line 471  code = (uschar *)re + re->name_table_off Line 1099  code = (uschar *)re + re->name_table_off
1099    (re->name_count * re->name_entry_size);    (re->name_count * re->name_entry_size);
1100    
1101  /* For an anchored pattern, or an unanchored pattern that has a first char, or  /* For an anchored pattern, or an unanchored pattern that has a first char, or
1102  a multiline pattern that matches only at "line starts", no further processing  a multiline pattern that matches only at "line starts", there is no point in
1103  at present. */  seeking a list of starting bytes. */
1104    
1105  if ((re->options & (PCRE_ANCHORED|PCRE_FIRSTSET|PCRE_STARTLINE)) != 0)  if ((re->options & PCRE_ANCHORED) == 0 &&
1106    return NULL;      (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
1107      {
1108      /* Set the character tables in the block that is passed around */
1109    
1110      tables = re->tables;
1111      if (tables == NULL)
1112        (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1113        (void *)(&tables));
1114    
1115      compile_block.lcc = tables + lcc_offset;
1116      compile_block.fcc = tables + fcc_offset;
1117      compile_block.cbits = tables + cbits_offset;
1118      compile_block.ctypes = tables + ctypes_offset;
1119    
1120      /* See if we can find a fixed set of initial characters for the pattern. */
1121    
1122      memset(start_bits, 0, 32 * sizeof(uschar));
1123      bits_set = set_start_bits(code, start_bits,
1124        (re->options & PCRE_CASELESS) != 0, (re->options & PCRE_UTF8) != 0,
1125        &compile_block) == SSB_DONE;
1126      }
1127    
1128    /* Find the minimum length of subject string. */
1129    
1130    min = find_minlength(code, code, re->options);
1131    
1132  /* Set the character tables in the block that is passed around */  /* Return NULL if no optimization is possible. */
1133    
1134  tables = re->tables;  if (!bits_set && min < 0) return NULL;
 if (tables == NULL)  
   (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,  
   (void *)(&tables));  
   
 compile_block.lcc = tables + lcc_offset;  
 compile_block.fcc = tables + fcc_offset;  
 compile_block.cbits = tables + cbits_offset;  
 compile_block.ctypes = tables + ctypes_offset;  
   
 /* See if we can find a fixed set of initial characters for the pattern. */  
   
 memset(start_bits, 0, 32 * sizeof(uschar));  
 if (!set_start_bits(code, start_bits, (re->options & PCRE_CASELESS) != 0,  
   (re->options & PCRE_UTF8) != 0, &compile_block)) return NULL;  
1135    
1136  /* Get a pcre_extra block and a pcre_study_data block. The study data is put in  /* Get a pcre_extra block and a pcre_study_data block. The study data is put in
1137  the latter, which is pointed to by the former, which may also get additional  the latter, which is pointed to by the former, which may also get additional
# Line 516  extra->flags = PCRE_EXTRA_STUDY_DATA; Line 1154  extra->flags = PCRE_EXTRA_STUDY_DATA;
1154  extra->study_data = study;  extra->study_data = study;
1155    
1156  study->size = sizeof(pcre_study_data);  study->size = sizeof(pcre_study_data);
1157  study->options = PCRE_STUDY_MAPPED;  study->flags = 0;
1158  memcpy(study->start_bits, start_bits, sizeof(start_bits));  
1159    if (bits_set)
1160      {
1161      study->flags |= PCRE_STUDY_MAPPED;
1162      memcpy(study->start_bits, start_bits, sizeof(start_bits));
1163      }
1164    
1165    if (min >= 0)
1166      {
1167      study->flags |= PCRE_STUDY_MINLEN;
1168      study->minlength = min;
1169      }
1170    
1171  return extra;  return extra;
1172  }  }
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