/[pcre]/code/trunk/pcre_dfa_exec.c
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Diff of /code/trunk/pcre_dfa_exec.c

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revision 455 by ph10, Sat Sep 26 19:12:32 2009 UTC revision 462 by ph10, Sat Oct 17 19:55:02 2009 UTC
# Line 45  FSM). This is NOT Perl- compatible, but Line 45  FSM). This is NOT Perl- compatible, but
45  applications. */  applications. */
46    
47    
48  /* NOTE ABOUT PERFORMANCE: A user of this function sent some code that improved  /* NOTE ABOUT PERFORMANCE: A user of this function sent some code that improved
49  the performance of his patterns greatly. I could not use it as it stood, as it  the performance of his patterns greatly. I could not use it as it stood, as it
50  was not thread safe, and made assumptions about pattern sizes. Also, it caused  was not thread safe, and made assumptions about pattern sizes. Also, it caused
51  test 7 to loop, and test 9 to crash with a segfault.  test 7 to loop, and test 9 to crash with a segfault.
52    
53  The issue is the check for duplicate states, which is done by a simple linear  The issue is the check for duplicate states, which is done by a simple linear
# Line 68  was the extra time to initialize the ind Line 68  was the extra time to initialize the ind
68  of internal_dfa_exec(). (The supplied patch used a static vector, initialized  of internal_dfa_exec(). (The supplied patch used a static vector, initialized
69  only once - I suspect this was the cause of the problems with the tests.)  only once - I suspect this was the cause of the problems with the tests.)
70    
71  Overall, I concluded that the gains in some cases did not outweigh the losses  Overall, I concluded that the gains in some cases did not outweigh the losses
72  in others, so I abandoned this code. */  in others, so I abandoned this code. */
73    
74    
# Line 109  never stored, so we push them well clear Line 109  never stored, so we push them well clear
109  character that is to be tested in some way. This makes is possible to  character that is to be tested in some way. This makes is possible to
110  centralize the loading of these characters. In the case of Type * etc, the  centralize the loading of these characters. In the case of Type * etc, the
111  "character" is the opcode for \D, \d, \S, \s, \W, or \w, which will always be a  "character" is the opcode for \D, \d, \S, \s, \W, or \w, which will always be a
112  small value. ***NOTE*** If the start of this table is modified, the two tables  small value. Non-zero values in the table are the offsets from the opcode where
113  that follow must also be modified. */  the character is to be found. ***NOTE*** If the start of this table is
114    modified, the three tables that follow must also be modified. */
115    
116  static const uschar coptable[] = {  static const uschar coptable[] = {
117    0,                             /* End                                    */    0,                             /* End                                    */
# Line 160  static const uschar coptable[] = { Line 161  static const uschar coptable[] = {
161    0,                             /* DEF                                    */    0,                             /* DEF                                    */
162    0, 0,                          /* BRAZERO, BRAMINZERO                    */    0, 0,                          /* BRAZERO, BRAMINZERO                    */
163    0, 0, 0, 0,                    /* PRUNE, SKIP, THEN, COMMIT              */    0, 0, 0, 0,                    /* PRUNE, SKIP, THEN, COMMIT              */
164    0, 0, 0                        /* FAIL, ACCEPT, SKIPZERO                 */    0, 0, 0, 0                     /* FAIL, ACCEPT, CLOSE, SKIPZERO          */
165    };
166    
167    /* This table identifies those opcodes that inspect a character. It is used to
168    remember the fact that a character could have been inspected when the end of
169    the subject is reached, in order to support PCRE_PARTIAL_HARD behaviour.
170    ***NOTE*** If the start of this table is modified, the two tables that follow
171    must also be modified. */
172    
173    static const uschar poptable[] = {
174      0,                             /* End                                    */
175      0, 0, 0, 0, 0,                 /* \A, \G, \K, \B, \b                     */
176      1, 1, 1, 1, 1, 1,              /* \D, \d, \S, \s, \W, \w                 */
177      1, 1, 1,                       /* Any, AllAny, Anybyte                   */
178      1, 1, 1,                       /* NOTPROP, PROP, EXTUNI                  */
179      1, 1, 1, 1, 1,                 /* \R, \H, \h, \V, \v                     */
180      0, 0, 0, 0, 0,                 /* \Z, \z, Opt, ^, $                      */
181      1,                             /* Char                                   */
182      1,                             /* Charnc                                 */
183      1,                             /* not                                    */
184      /* Positive single-char repeats                                          */
185      1, 1, 1, 1, 1, 1,              /* *, *?, +, +?, ?, ??                    */
186      1, 1, 1,                       /* upto, minupto, exact                   */
187      1, 1, 1, 1,                    /* *+, ++, ?+, upto+                      */
188      /* Negative single-char repeats - only for chars < 256                   */
189      1, 1, 1, 1, 1, 1,              /* NOT *, *?, +, +?, ?, ??                */
190      1, 1, 1,                       /* NOT upto, minupto, exact               */
191      1, 1, 1, 1,                    /* NOT *+, ++, ?+, upto+                  */
192      /* Positive type repeats                                                 */
193      1, 1, 1, 1, 1, 1,              /* Type *, *?, +, +?, ?, ??               */
194      1, 1, 1,                       /* Type upto, minupto, exact              */
195      1, 1, 1, 1,                    /* Type *+, ++, ?+, upto+                 */
196      /* Character class & ref repeats                                         */
197      1, 1, 1, 1, 1, 1,              /* *, *?, +, +?, ?, ??                    */
198      1, 1,                          /* CRRANGE, CRMINRANGE                    */
199      1,                             /* CLASS                                  */
200      1,                             /* NCLASS                                 */
201      1,                             /* XCLASS - variable length               */
202      0,                             /* REF                                    */
203      0,                             /* RECURSE                                */
204      0,                             /* CALLOUT                                */
205      0,                             /* Alt                                    */
206      0,                             /* Ket                                    */
207      0,                             /* KetRmax                                */
208      0,                             /* KetRmin                                */
209      0,                             /* Assert                                 */
210      0,                             /* Assert not                             */
211      0,                             /* Assert behind                          */
212      0,                             /* Assert behind not                      */
213      0,                             /* Reverse                                */
214      0, 0, 0, 0,                    /* ONCE, BRA, CBRA, COND                  */
215      0, 0, 0,                       /* SBRA, SCBRA, SCOND                     */
216      0,                             /* CREF                                   */
217      0,                             /* RREF                                   */
218      0,                             /* DEF                                    */
219      0, 0,                          /* BRAZERO, BRAMINZERO                    */
220      0, 0, 0, 0,                    /* PRUNE, SKIP, THEN, COMMIT              */
221      0, 0, 0, 0                     /* FAIL, ACCEPT, CLOSE, SKIPZERO          */
222  };  };
223    
224  /* These 2 tables allow for compact code for testing for \D, \d, \S, \s, \W,  /* These 2 tables allow for compact code for testing for \D, \d, \S, \s, \W,
# Line 417  if (*first_op == OP_REVERSE) Line 475  if (*first_op == OP_REVERSE)
475        current_subject - start_subject : max_back;        current_subject - start_subject : max_back;
476      current_subject -= gone_back;      current_subject -= gone_back;
477      }      }
478    
479    /* Save the earliest consulted character */    /* Save the earliest consulted character */
480    
481    if (current_subject < md->start_used_ptr)    if (current_subject < md->start_used_ptr)
482      md->start_used_ptr = current_subject;      md->start_used_ptr = current_subject;
483    
484    /* Now we can process the individual branches. */    /* Now we can process the individual branches. */
485    
# Line 488  for (;;) Line 546  for (;;)
546    int clen, dlen;    int clen, dlen;
547    unsigned int c, d;    unsigned int c, d;
548    int forced_fail = 0;    int forced_fail = 0;
549    int reached_end = 0;    int reached_end = 0;
550      BOOL could_continue = FALSE;
551    
552    /* Make the new state list into the active state list and empty the    /* Make the new state list into the active state list and empty the
553    new state list. */    new state list. */
# Line 578  for (;;) Line 637  for (;;)
637          }          }
638        }        }
639    
640      /* Check for a duplicate state with the same count, and skip if found.      /* Check for a duplicate state with the same count, and skip if found.
641      See the note at the head of this module about the possibility of improving      See the note at the head of this module about the possibility of improving
642      performance here. */      performance here. */
643    
# Line 596  for (;;) Line 655  for (;;)
655    
656      code = start_code + state_offset;      code = start_code + state_offset;
657      codevalue = *code;      codevalue = *code;
658    
659        /* If this opcode inspects a character, but we are at the end of the
660        subject, remember the fact so that we can support PCRE_PARTIAL_HARD. */
661    
662        if (clen == 0 && poptable[codevalue] != 0)
663          could_continue = TRUE;
664    
665      /* If this opcode is followed by an inline character, load it. It is      /* If this opcode is followed by an inline character, load it. It is
666      tempting to test for the presence of a subject character here, but that      tempting to test for the presence of a subject character here, but that
# Line 647  for (;;) Line 712  for (;;)
712  /* ========================================================================== */  /* ========================================================================== */
713        /* Reached a closing bracket. If not at the end of the pattern, carry        /* Reached a closing bracket. If not at the end of the pattern, carry
714        on with the next opcode. Otherwise, unless we have an empty string and        on with the next opcode. Otherwise, unless we have an empty string and
715        PCRE_NOTEMPTY is set, or PCRE_NOTEMPTY_ATSTART is set and we are at the        PCRE_NOTEMPTY is set, or PCRE_NOTEMPTY_ATSTART is set and we are at the
716        start of the subject, save the match data, shifting up all previous        start of the subject, save the match data, shifting up all previous
717        matches so we always have the longest first. */        matches so we always have the longest first. */
718    
# Line 662  for (;;) Line 727  for (;;)
727            ADD_ACTIVE(state_offset - GET(code, 1), 0);            ADD_ACTIVE(state_offset - GET(code, 1), 0);
728            }            }
729          }          }
730        else        else
731          {          {
732          reached_end++;    /* Count branches that reach the end */          reached_end++;    /* Count branches that reach the end */
733          if (ptr > current_subject ||          if (ptr > current_subject ||
734              ((md->moptions & PCRE_NOTEMPTY) == 0 &&              ((md->moptions & PCRE_NOTEMPTY) == 0 &&
735                ((md->moptions & PCRE_NOTEMPTY_ATSTART) == 0 ||                ((md->moptions & PCRE_NOTEMPTY_ATSTART) == 0 ||
736                  current_subject > start_subject + md->start_offset)))                  current_subject > start_subject + md->start_offset)))
# Line 689  for (;;) Line 754  for (;;)
754                match_count, rlevel*2-2, SP));                match_count, rlevel*2-2, SP));
755              return match_count;              return match_count;
756              }              }
757            }            }
758          }          }
759        break;        break;
760    
# Line 839  for (;;) Line 904  for (;;)
904          if (ptr > start_subject)          if (ptr > start_subject)
905            {            {
906            const uschar *temp = ptr - 1;            const uschar *temp = ptr - 1;
907            if (temp < md->start_used_ptr) md->start_used_ptr = temp;            if (temp < md->start_used_ptr) md->start_used_ptr = temp;
908  #ifdef SUPPORT_UTF8  #ifdef SUPPORT_UTF8
909            if (utf8) BACKCHAR(temp);            if (utf8) BACKCHAR(temp);
910  #endif  #endif
# Line 848  for (;;) Line 913  for (;;)
913            }            }
914          else left_word = 0;          else left_word = 0;
915    
916          if (clen > 0)          if (clen > 0)
917            right_word = c < 256 && (ctypes[c] & ctype_word) != 0;            right_word = c < 256 && (ctypes[c] & ctype_word) != 0;
918          else              /* This is a fudge to ensure that if this is the */          else              /* This is a fudge to ensure that if this is the */
919            {               /* last item in the pattern, we don't count it as */            {               /* last item in the pattern, we don't count it as */
920            reached_end--;  /* reached, thus disabling a partial match. */            reached_end--;  /* reached, thus disabling a partial match. */
921            right_word = 0;            right_word = 0;
922            }            }
923    
924          if ((left_word == right_word) == (codevalue == OP_NOT_WORD_BOUNDARY))          if ((left_word == right_word) == (codevalue == OP_NOT_WORD_BOUNDARY))
925            { ADD_ACTIVE(state_offset + 1, 0); }            { ADD_ACTIVE(state_offset + 1, 0); }
# Line 2287  for (;;) Line 2352  for (;;)
2352    
2353          /* Back reference conditions are not supported */          /* Back reference conditions are not supported */
2354    
2355          if (condcode == OP_CREF) return PCRE_ERROR_DFA_UCOND;          if (condcode == OP_CREF || condcode == OP_NCREF)
2356              return PCRE_ERROR_DFA_UCOND;
2357    
2358          /* The DEFINE condition is always false */          /* The DEFINE condition is always false */
2359    
# Line 2298  for (;;) Line 2364  for (;;)
2364          which means "test if in any recursion". We can't test for specifically          which means "test if in any recursion". We can't test for specifically
2365          recursed groups. */          recursed groups. */
2366    
2367          else if (condcode == OP_RREF)          else if (condcode == OP_RREF || condcode == OP_NRREF)
2368            {            {
2369            int value = GET2(code, LINK_SIZE+2);            int value = GET2(code, LINK_SIZE+2);
2370            if (value != RREF_ANY) return PCRE_ERROR_DFA_UCOND;            if (value != RREF_ANY) return PCRE_ERROR_DFA_UCOND;
# Line 2521  for (;;) Line 2587  for (;;)
2587    /* We have finished the processing at the current subject character. If no    /* We have finished the processing at the current subject character. If no
2588    new states have been set for the next character, we have found all the    new states have been set for the next character, we have found all the
2589    matches that we are going to find. If we are at the top level and partial    matches that we are going to find. If we are at the top level and partial
2590    matching has been requested, check for appropriate conditions. The "forced_    matching has been requested, check for appropriate conditions.
2591    fail" variable counts the number of (*F) encountered for the character. If it  
2592    is equal to the original active_count (saved in workspace[1]) it means that    The "forced_ fail" variable counts the number of (*F) encountered for the
2593    (*F) was found on every active state. In this case we don't want to give a    character. If it is equal to the original active_count (saved in
2594    partial match. */    workspace[1]) it means that (*F) was found on every active state. In this
2595      case we don't want to give a partial match.
2596    
2597      The "reached_end" variable counts the number of threads that have reached the
2598      end of the pattern. The "could_continue" variable is true if a thread could
2599      have continued but for the fact that the end of the subject was reached. */
2600    
2601    if (new_count <= 0)    if (new_count <= 0)
2602      {      {
2603      if (rlevel == 1 &&                               /* Top level, and */      if (rlevel == 1 &&                               /* Top level, and */
2604          reached_end != workspace[1] &&               /* Not all reached end */          (                                            /* either... */
2605            reached_end != workspace[1] ||               /* Not all reached end */
2606              could_continue                             /* or some could go on */
2607            ) &&                                         /* and... */
2608          forced_fail != workspace[1] &&               /* Not all forced fail & */          forced_fail != workspace[1] &&               /* Not all forced fail & */
2609          (                                            /* either... */          (                                            /* either... */
2610          (md->moptions & PCRE_PARTIAL_HARD) != 0      /* Hard partial */          (md->moptions & PCRE_PARTIAL_HARD) != 0      /* Hard partial */
# Line 2651  if (extra_data != NULL) Line 2725  if (extra_data != NULL)
2725    if ((flags & PCRE_EXTRA_TABLES) != 0)    if ((flags & PCRE_EXTRA_TABLES) != 0)
2726      md->tables = extra_data->tables;      md->tables = extra_data->tables;
2727    }    }
2728    
2729  /* Check that the first field in the block is the magic number. If it is not,  /* Check that the first field in the block is the magic number. If it is not,
2730  test for a regex that was compiled on a host of opposite endianness. If this is  test for a regex that was compiled on a host of opposite endianness. If this is
2731  the case, flipped values are put in internal_re and internal_study if there was  the case, flipped values are put in internal_re and internal_study if there was
# Line 2913  for (;;) Line 2987  for (;;)
2987    
2988      end_subject = save_end_subject;      end_subject = save_end_subject;
2989    
2990      /* The following two optimizations are disabled for partial matching or if      /* The following two optimizations are disabled for partial matching or if
2991      disabling is explicitly requested (and of course, by the test above, this      disabling is explicitly requested (and of course, by the test above, this
2992      code is not obeyed when restarting after a partial match). */      code is not obeyed when restarting after a partial match). */
2993    
2994      if ((options & PCRE_NO_START_OPTIMIZE) == 0 &&      if ((options & PCRE_NO_START_OPTIMIZE) == 0 &&
2995          (options & (PCRE_PARTIAL_HARD|PCRE_PARTIAL_SOFT)) == 0)          (options & (PCRE_PARTIAL_HARD|PCRE_PARTIAL_SOFT)) == 0)
2996        {        {
2997        /* If the pattern was studied, a minimum subject length may be set. This        /* If the pattern was studied, a minimum subject length may be set. This
2998        is a lower bound; no actual string of that length may actually match the        is a lower bound; no actual string of that length may actually match the
2999        pattern. Although the value is, strictly, in characters, we treat it as        pattern. Although the value is, strictly, in characters, we treat it as
# Line 2928  for (;;) Line 3002  for (;;)
3002        if (study != NULL && (study->flags & PCRE_STUDY_MINLEN) != 0 &&        if (study != NULL && (study->flags & PCRE_STUDY_MINLEN) != 0 &&
3003            end_subject - current_subject < study->minlength)            end_subject - current_subject < study->minlength)
3004          return PCRE_ERROR_NOMATCH;          return PCRE_ERROR_NOMATCH;
3005    
3006        /* If req_byte is set, we know that that character must appear in the        /* If req_byte is set, we know that that character must appear in the
3007        subject for the match to succeed. If the first character is set, req_byte        subject for the match to succeed. If the first character is set, req_byte
3008        must be later in the subject; otherwise the test starts at the match        must be later in the subject; otherwise the test starts at the match
# Line 2936  for (;;) Line 3010  for (;;)
3010        nested unlimited repeats that aren't going to match. Writing separate        nested unlimited repeats that aren't going to match. Writing separate
3011        code for cased/caseless versions makes it go faster, as does using an        code for cased/caseless versions makes it go faster, as does using an
3012        autoincrement and backing off on a match.        autoincrement and backing off on a match.
3013    
3014        HOWEVER: when the subject string is very, very long, searching to its end        HOWEVER: when the subject string is very, very long, searching to its end
3015        can take a long time, and give bad performance on quite ordinary        can take a long time, and give bad performance on quite ordinary
3016        patterns. This showed up when somebody was matching /^C/ on a 32-megabyte        patterns. This showed up when somebody was matching /^C/ on a 32-megabyte
3017        string... so we don't do this when the string is sufficiently long. */        string... so we don't do this when the string is sufficiently long. */
3018    
3019        if (req_byte >= 0 && end_subject - current_subject < REQ_BYTE_MAX)        if (req_byte >= 0 && end_subject - current_subject < REQ_BYTE_MAX)
3020          {          {
3021          register const uschar *p = current_subject + ((first_byte >= 0)? 1 : 0);          register const uschar *p = current_subject + ((first_byte >= 0)? 1 : 0);
3022    
3023          /* We don't need to repeat the search if we haven't yet reached the          /* We don't need to repeat the search if we haven't yet reached the
3024          place we found it at last time. */          place we found it at last time. */
3025    
3026          if (p > req_byte_ptr)          if (p > req_byte_ptr)
3027            {            {
3028            if (req_byte_caseless)            if (req_byte_caseless)
# Line 2966  for (;;) Line 3040  for (;;)
3040                if (*p++ == req_byte) { p--; break; }                if (*p++ == req_byte) { p--; break; }
3041                }                }
3042              }              }
3043    
3044            /* If we can't find the required character, break the matching loop,            /* If we can't find the required character, break the matching loop,
3045            which will cause a return or PCRE_ERROR_NOMATCH. */            which will cause a return or PCRE_ERROR_NOMATCH. */
3046    
3047            if (p >= end_subject) break;            if (p >= end_subject) break;
3048    
3049            /* If we have found the required character, save the point where we            /* If we have found the required character, save the point where we
3050            found it, so that we don't search again next time round the loop if            found it, so that we don't search again next time round the loop if
3051            the start hasn't passed this character yet. */            the start hasn't passed this character yet. */
3052    
3053            req_byte_ptr = p;            req_byte_ptr = p;
3054            }            }
3055          }          }
3056        }        }
3057      }   /* End of optimizations that are done when not restarting */      }   /* End of optimizations that are done when not restarting */
3058    
3059    /* OK, now we can do the business */    /* OK, now we can do the business */
3060    
3061    md->start_used_ptr = current_subject;    md->start_used_ptr = current_subject;
3062    
3063    rc = internal_dfa_exec(    rc = internal_dfa_exec(
3064      md,                                /* fixed match data */      md,                                /* fixed match data */
3065      md->start_code,                    /* this subexpression's code */      md->start_code,                    /* this subexpression's code */

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