/[pcre]/code/trunk/pcre.c

Diff of /code/trunk/pcre.c

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-revision 21 by nigel,
Sat Feb 24 21:38:37 2007 UTC
+revision 23 by nigel,
Sat Feb 24 21:38:41 2007 UTC
 Line 33 
 restrictions:
  /* #define DEBUG */
- /* Use a macro for debugging printing, 'cause that eliminates the the use
+ /* Use a macro for debugging printing, 'cause that eliminates the use of #ifdef
- of #ifdef inline, and there are *still* stupid compilers about that don't like
+ inline, and there are *still* stupid compilers about that don't like indented
- indented pre-processor statements. I suppose it's only been 10 years... */
+ pre-processor statements. I suppose it's only been 10 years... */
  #ifdef DEBUG
  #define DPRINTF(p) printf p
 Line 56 
 the external pcre header. */
  #endif
+ /* Number of items on the nested bracket stacks at compile time. This should
+ not be set greater than 200. */
+ #define BRASTACK_SIZE 200
  /* Min and max values for the common repeats; for the maxima, 0 => infinity */
  static const char rep_min[] = { 0, 0, 1, 1, 0, 0 };
-Line 66 
 static const char rep_max[] = { 0, 0, 0,
+Line 72 
 static const char rep_max[] = { 0, 0, 0,
  #ifdef DEBUG
  static const char *OP_names[] = {
    "End", "\\A", "\\B", "\\b", "\\D", "\\d",
-   "\\S", "\\s", "\\W", "\\w", "Cut", "\\Z", "^", "$", "Any", "chars",
+   "\\S", "\\s", "\\W", "\\w", "\\Z", "\\z",
-   "not",
+   "Opt", "^", "$", "Any", "chars", "not",
    "*", "*?", "+", "+?", "?", "??", "{", "{", "{",
    "*", "*?", "+", "+?", "?", "??", "{", "{", "{",
    "*", "*?", "+", "+?", "?", "??", "{", "{", "{",
    "*", "*?", "+", "+?", "?", "??", "{", "{",
-   "class", "negclass", "Ref",
+   "class", "Ref",
-   "Alt", "Ket", "KetRmax", "KetRmin", "Assert", "Assert not", "Once",
+   "Alt", "Ket", "KetRmax", "KetRmin", "Assert", "Assert not",
+   "AssertB", "AssertB not", "Reverse", "Once", "Cond", "Cref",
    "Brazero", "Braminzero", "Bra"
  };
  #endif
-Line 93 
 static const short int escapes[] = {
+Line 100 
 static const short int escapes[] = {
    '`',      7, -ESC_b,      0, -ESC_d,     27,   '\f',      0,   /* ` - g */
 ,      0,      0,      0,      0,      0,   '\n',      0,   /* h - o */
 ,      0,   '\r', -ESC_s,   '\t',      0,      0, -ESC_w,   /* p - w */
-,      0,      0                                            /* x - z */
+,      0, -ESC_z                                            /* x - z */
  };
  /* Definition to allow mutual recursion */
  static BOOL
-   compile_regex(int, int *, uschar **, const uschar **, const char **);
+   compile_regex(int, int, int *, uschar **, const uschar **, const char **,
+     BOOL, int);
  /* Structure for passing "static" information around between the functions
  doing the matching, so that they are thread-safe. */
-Line 108 
 typedef struct match_data {
+Line 116 
 typedef struct match_data {
    int    errorcode;             /* As it says */
    int   *offset_vector;         /* Offset vector */
    int    offset_end;            /* One past the end */
+   int    offset_max;            /* The maximum usable for return data */
    BOOL   offset_overflow;       /* Set if too many extractions */
-   BOOL   caseless;              /* Case-independent flag */
-   BOOL   runtime_caseless;      /* Caseless forced at run time */
-   BOOL   multiline;             /* Multiline flag */
    BOOL   notbol;                /* NOTBOL flag */
    BOOL   noteol;                /* NOTEOL flag */
-   BOOL   dotall;                /* Dot matches any char */
    BOOL   endonly;               /* Dollar not before final \n */
    const uschar *start_subject;  /* Start of the subject string */
    const uschar *end_subject;    /* End of the subject string */
-   jmp_buf fail_env;             /* Environment for longjump() break out */
    const uschar *end_match_ptr;  /* Subject position at end match */
    int     end_offset_top;       /* Highwater mark at end of match */
  } match_data;
-Line 218 
 while (length-- > 0)
+Line 222 
 while (length-- > 0)
  /*************************************************
- *         Check subpattern for empty operand     *
- *************************************************/
- /* This function checks a bracketed subpattern to see if any of the paths
- through it could match an empty string. This is used to diagnose an error if
- such a subpattern is followed by a quantifier with an unlimited upper bound.
- Argument:
-   code      points to the opening bracket
- Returns:    TRUE or FALSE
- */
- static BOOL
- could_be_empty(uschar *code)
- {
- do {
-   uschar *cc = code + 3;
-   /* Scan along the opcodes for this branch; as soon as we find something
-   that matches a non-empty string, break out and advance to test the next
-   branch. If we get to the end of the branch, return TRUE for the whole
-   sub-expression. */
-   for (;;)
-     {
-     /* Test an embedded subpattern; if it could not be empty, break the
-     loop. Otherwise carry on in the branch. */
-     if ((int)(*cc) >= OP_BRA || (int)(*cc) == OP_ONCE)
-       {
-       if (!could_be_empty(cc)) break;
-       do cc += (cc[1] << 8) + cc[2]; while (*cc == OP_ALT);
-       cc += 3;
-       }
-     else switch (*cc)
-       {
-       /* Reached end of a branch: the subpattern may match the empty string */
-       case OP_ALT:
-       case OP_KET:
-       case OP_KETRMAX:
-       case OP_KETRMIN:
-       return TRUE;
-       /* Skip over entire bracket groups with zero lower bound */
-       case OP_BRAZERO:
-       case OP_BRAMINZERO:
-       cc++;
-       /* Fall through */
-       /* Skip over assertive subpatterns */
-       case OP_ASSERT:
-       case OP_ASSERT_NOT:
-       do cc += (cc[1] << 8) + cc[2]; while (*cc == OP_ALT);
-       cc += 3;
-       break;
-       /* Skip over things that don't match chars */
-       case OP_SOD:
-       case OP_EOD:
-       case OP_CIRC:
-       case OP_DOLL:
-       case OP_NOT_WORD_BOUNDARY:
-       case OP_WORD_BOUNDARY:
-       cc++;
-       break;
-       /* Skip over simple repeats with zero lower bound */
-       case OP_STAR:
-       case OP_MINSTAR:
-       case OP_QUERY:
-       case OP_MINQUERY:
-       case OP_NOTSTAR:
-       case OP_NOTMINSTAR:
-       case OP_NOTQUERY:
-       case OP_NOTMINQUERY:
-       case OP_TYPESTAR:
-       case OP_TYPEMINSTAR:
-       case OP_TYPEQUERY:
-       case OP_TYPEMINQUERY:
-       cc += 2;
-       break;
-       /* Skip over UPTOs (lower bound is zero) */
-       case OP_UPTO:
-       case OP_MINUPTO:
-       case OP_TYPEUPTO:
-       case OP_TYPEMINUPTO:
-       cc += 4;
-       break;
-       /* Check a class or a back reference for a zero minimum */
-       case OP_CLASS:
-       case OP_NEGCLASS:
-       case OP_REF:
-       cc += (*cc == OP_REF)? 2 : 33;
-       switch (*cc)
-         {
-         case OP_CRSTAR:
-         case OP_CRMINSTAR:
-         case OP_CRQUERY:
-         case OP_CRMINQUERY:
-         cc++;
-         break;
-         case OP_CRRANGE:
-         case OP_CRMINRANGE:
-         if ((cc[1] << 8) + cc[2] != 0) goto NEXT_BRANCH;
-         cc += 3;
-         break;
-         default:
-         goto NEXT_BRANCH;
-         }
-       break;
-       /* Anything else matches at least one character */
-       default:
-       goto NEXT_BRANCH;
-       }
-     }
-   NEXT_BRANCH:
-   code += (code[1] << 8) + code[2];
-   }
- while (*code == OP_ALT);
- /* No branches match the empty string */
- return FALSE;
- }
- /*************************************************
  *            Handle escapes                      *
  *************************************************/
-Line 493 
 else
+Line 352 
 else
      default:
      if ((options & PCRE_EXTRA) != 0) switch(c)
        {
-       case 'X':
-       c = -ESC_X;      /* This could be a lookup if it ever got into Perl */
-       break;
        default:
        *errorptr = ERR3;
        break;
-Line 600 
 return p;
+Line 455 
 return p;
  /*************************************************
+ *        Find the fixed length of a pattern      *
+ *************************************************/
+ /* Scan a pattern and compute the fixed length of subject that will match it,
+ if the length is fixed. This is needed for dealing with backward assertions.
+ Arguments:
+   code     points to the start of the pattern (the bracket)
+ Returns:   the fixed length, or -1 if there is no fixed length
+ */
+ static int
+ find_fixedlength(uschar *code)
+ {
+ int length = -1;
+ register int branchlength = 0;
+ register uschar *cc = code + 3;
+ /* Scan along the opcodes for this branch. If we get to the end of the
+ branch, check the length against that of the other branches. */
+ for (;;)
+   {
+   int d;
+   register int op = *cc;
+   if (op >= OP_BRA) op = OP_BRA;
+   switch (op)
+     {
+     case OP_BRA:
+     case OP_ONCE:
+     case OP_COND:
+     d = find_fixedlength(cc);
+     if (d < 0) return -1;
+     branchlength += d;
+     do cc += (cc[1] << 8) + cc[2]; while (*cc == OP_ALT);
+     cc += 3;
+     break;
+     /* Reached end of a branch; if it's a ket it is the end of a nested
+     call. If it's ALT it is an alternation in a nested call. If it is
+     END it's the end of the outer call. All can be handled by the same code. */
+     case OP_ALT:
+     case OP_KET:
+     case OP_KETRMAX:
+     case OP_KETRMIN:
+     case OP_END:
+     if (length < 0) length = branchlength;
+       else if (length != branchlength) return -1;
+     if (*cc != OP_ALT) return length;
+     cc += 3;
+     branchlength = 0;
+     break;
+     /* Skip over assertive subpatterns */
+     case OP_ASSERT:
+     case OP_ASSERT_NOT:
+     case OP_ASSERTBACK:
+     case OP_ASSERTBACK_NOT:
+     do cc += (cc[1] << 8) + cc[2]; while (*cc == OP_ALT);
+     cc += 3;
+     break;
+     /* Skip over things that don't match chars */
+     case OP_REVERSE:
+     cc++;
+     case OP_CREF:
+     case OP_OPT:
+     cc++;
+     /* Fall through */
+     case OP_SOD:
+     case OP_EOD:
+     case OP_EODN:
+     case OP_CIRC:
+     case OP_DOLL:
+     case OP_NOT_WORD_BOUNDARY:
+     case OP_WORD_BOUNDARY:
+     cc++;
+     break;
+     /* Handle char strings */
+     case OP_CHARS:
+     branchlength += *(++cc);
+     cc += *cc + 1;
+     break;
+     /* Handle exact repetitions */
+     case OP_EXACT:
+     case OP_TYPEEXACT:
+     branchlength += (cc[1] << 8) + cc[2];
+     cc += 4;
+     break;
+     /* Handle single-char matchers */
+     case OP_NOT_DIGIT:
+     case OP_DIGIT:
+     case OP_NOT_WHITESPACE:
+     case OP_WHITESPACE:
+     case OP_NOT_WORDCHAR:
+     case OP_WORDCHAR:
+     case OP_ANY:
+     branchlength++;
+     cc++;
+     break;
+     /* Check a class for variable quantification */
+     case OP_CLASS:
+     cc += (*cc == OP_REF)? 2 : 33;
+     switch (*cc)
+       {
+       case OP_CRSTAR:
+       case OP_CRMINSTAR:
+       case OP_CRQUERY:
+       case OP_CRMINQUERY:
+       return -1;
+       case OP_CRRANGE:
+       case OP_CRMINRANGE:
+       if ((cc[1] << 8) + cc[2] != (cc[3] << 8) + cc[4]) return -1;
+       branchlength += (cc[1] << 8) + cc[2];
+       cc += 5;
+       break;
+       default:
+       branchlength++;
+       }
+     break;
+     /* Anything else is variable length */
+     default:
+     return -1;
+     }
+   }
+ /* Control never gets here */
+ }
+ /*************************************************
  *           Compile one branch                   *
  *************************************************/
  /* Scan the pattern, compiling it into the code vector.
  Arguments:
-   options    the option bits
+   options     the option bits
-   bracket    points to number of brackets used
+   brackets    points to number of brackets used
-   code       points to the pointer to the current code point
+   code        points to the pointer to the current code point
-   ptrptr     points to the current pattern pointer
+   ptrptr      points to the current pattern pointer
-   errorptr   points to pointer to error message
+   errorptr    points to pointer to error message
+   optchanged  set to the value of the last OP_OPT item compiled
- Returns:     TRUE on success
+ Returns:      TRUE on success
-              FALSE, with *errorptr set on error
+               FALSE, with *errorptr set on error
  */
  static BOOL
  compile_branch(int options, int *brackets, uschar **codeptr,
-   const uschar **ptrptr, const char **errorptr)
+   const uschar **ptrptr, const char **errorptr, int *optchanged)
  {
  int repeat_type, op_type;
  int repeat_min, repeat_max;
-Line 626 
 int bravalue, length;
+Line 636 
 int bravalue, length;
  int greedy_default, greedy_non_default;
  register int c;
  register uschar *code = *codeptr;
+ uschar *tempcode;
  const uschar *ptr = *ptrptr;
- const uschar *oldptr;
+ const uschar *tempptr;
  uschar *previous = NULL;
  uschar class[32];
-Line 641 
 greedy_non_default = greedy_default ^ 1;
+Line 652 
 greedy_non_default = greedy_default ^ 1;
  for (;; ptr++)
    {
    BOOL negate_class;
-   int  class_charcount;
+   int class_charcount;
-   int  class_lastchar;
+   int class_lastchar;
+   int newoptions;
+   int condref;
    c = *ptr;
    if ((options & PCRE_EXTENDED) != 0)
-Line 690 
 for (;; ptr++)
+Line 703 
 for (;; ptr++)
      case '[':
      previous = code;
+     *code++ = OP_CLASS;
-     /* If the first character is '^', set the negation flag, and use a
+     /* If the first character is '^', set the negation flag and skip it. */
-     different opcode. This only matters if caseless matching is specified at
-     runtime. */
      if ((c = *(++ptr)) == '^')
        {
        negate_class = TRUE;
-       *code++ = OP_NEGCLASS;
        c = *(++ptr);
        }
-     else
+     else negate_class = FALSE;
-       {
-       negate_class = FALSE;
-       *code++ = OP_CLASS;
-       }
      /* Keep a count of chars so that we can optimize the case of just a single
      character. */
-Line 964 
 for (;; ptr++)
+Line 971 
 for (;; ptr++)
      create a suitable repeat item. The code is shared with single-character
      repeats by adding a suitable offset into repeat_type. */
-     else if ((int)*previous < OP_EOD || *previous == OP_ANY)
+     else if ((int)*previous < OP_EODN || *previous == OP_ANY)
        {
        op_type = OP_TYPESTAR - OP_STAR;  /* Use type opcodes */
        c = *previous;
-Line 1050 
 for (;; ptr++)
+Line 1057 
 for (;; ptr++)
      /* If previous was a character class or a back reference, we put the repeat
      stuff after it. */
-     else if (*previous == OP_CLASS || *previous == OP_NEGCLASS ||
+     else if (*previous == OP_CLASS || *previous == OP_REF)
-              *previous == OP_REF)
        {
        if (repeat_min == 0 && repeat_max == -1)
          *code++ = OP_CRSTAR + repeat_type;
-Line 1071 
 for (;; ptr++)
+Line 1077 
 for (;; ptr++)
        }
      /* If previous was a bracket group, we may have to replicate it in certain
-     cases. If the maximum repeat count is unlimited, check that the bracket
+     cases. */
-     group cannot match the empty string, and diagnose an error if it can. */
-     else if ((int)*previous >= OP_BRA)
+     else if ((int)*previous >= OP_BRA || (int)*previous == OP_ONCE ||
+              (int)*previous == OP_COND)
        {
-       int i;
+       int i, ketoffset = 0;
        int len = code - previous;
-       if (repeat_max == -1 && could_be_empty(previous))
+       /* If the maximum repeat count is unlimited, find the end of the bracket
-         {
+       by scanning through from the start, and compute the offset back to it
-         *errorptr = ERR10;
+       from the current code pointer. There may be an OP_OPT setting following
-         goto FAILED;
+       the final KET, so we can't find the end just by going back from the code
+       pointer. */
+       if (repeat_max == -1)
+         {
+         register uschar *ket = previous;
+         do ket += (ket[1] << 8) + ket[2]; while (*ket != OP_KET);
+         ketoffset = code - ket;
          }
        /* If the minimum is greater than zero, and the maximum is unlimited or
-Line 1126 
 for (;; ptr++)
+Line 1139 
 for (;; ptr++)
            }
          }
-       /* If the maximum is unlimited, set a repeater in the final copy. */
+       /* If the maximum is unlimited, set a repeater in the final copy. We
+       can't just offset backwards from the current code point, because we
+       don't know if there's been an options resetting after the ket. The
+       correct offset was computed above. */
-       if (repeat_max == -1) code[-3] = OP_KETRMAX + repeat_type;
+       if (repeat_max == -1) code[-ketoffset] = OP_KETRMAX + repeat_type;
        }
      /* Else there's some kind of shambles */
-Line 1145 
 for (;; ptr++)
+Line 1161 
 for (;; ptr++)
      break;
-     /* Start of nested bracket sub-expression, or comment or lookahead.
+     /* Start of nested bracket sub-expression, or comment or lookahead or
-     First deal with special things that can come after a bracket; all are
+     lookbehind or option setting or condition. First deal with special things
-     introduced by ?, and the appearance of any of them means that this is not a
+     that can come after a bracket; all are introduced by ?, and the appearance
-     referencing group. They were checked for validity in the first pass over
+     of any of them means that this is not a referencing group. They were
-     the string, so we don't have to check for syntax errors here.  */
+     checked for validity in the first pass over the string, so we don't have to
+     check for syntax errors here.  */
      case '(':
-     previous = code;              /* Only real brackets can be repeated */
+     newoptions = options;
+     condref = -1;
      if (*(++ptr) == '?')
        {
-       bravalue = OP_BRA;
+       int set, unset;
+       int *optset;
        switch (*(++ptr))
          {
-         case '#':
+         case '#':                 /* Comment; skip to ket */
-         case 'i':
-         case 'm':
-         case 's':
-         case 'x':
-         case 'U':
-         case 'X':
          ptr++;
          while (*ptr != ')') ptr++;
-         previous = NULL;
          continue;
          case ':':                 /* Non-extracting bracket */
+         bravalue = OP_BRA;
          ptr++;
          break;
-         case '=':                 /* Assertions can't be repeated */
+         case '(':
+         bravalue = OP_COND;       /* Conditional group */
+         if ((pcre_ctypes[*(++ptr)] & ctype_digit) != 0)
+           {
+           condref = *ptr - '0';
+           while (*(++ptr) != ')') condref = condref*10 + *ptr - '0';
+           ptr++;
+           }
+         else ptr--;
+         break;
+         case '=':                 /* Positive lookahead */
          bravalue = OP_ASSERT;
          ptr++;
-         previous = NULL;
          break;
-         case '!':
+         case '!':                 /* Negative lookahead */
          bravalue = OP_ASSERT_NOT;
          ptr++;
-         previous = NULL;
          break;
-         case '>':                         /* "Match once" brackets */
+         case '<':                 /* Lookbehinds */
-         if ((options & PCRE_EXTRA) != 0)  /* Not yet standard */
+         switch (*(++ptr))
            {
-           bravalue = OP_ONCE;
+           case '=':               /* Positive lookbehind */
+           bravalue = OP_ASSERTBACK;
+           ptr++;
+           break;
+           case '!':               /* Negative lookbehind */
+           bravalue = OP_ASSERTBACK_NOT;
            ptr++;
-           previous = NULL;
            break;
+           default:                /* Syntax error */
+           *errorptr = ERR24;
+           goto FAILED;
            }
-         /* Else fall through */
+         break;
-         default:
+         case '>':                 /* One-time brackets */
-         *errorptr = ERR12;
+         bravalue = OP_ONCE;
-         goto FAILED;
+         ptr++;
+         break;
+         default:                  /* Option setting */
+         set = unset = 0;
+         optset = &set;
+         while (*ptr != ')' && *ptr != ':')
+           {
+           switch (*ptr++)
+             {
+             case '-': optset = &unset; break;
+             case 'i': *optset |= PCRE_CASELESS; break;
+             case 'm': *optset |= PCRE_MULTILINE; break;
+             case 's': *optset |= PCRE_DOTALL; break;
+             case 'x': *optset |= PCRE_EXTENDED; break;
+             case 'U': *optset |= PCRE_UNGREEDY; break;
+             case 'X': *optset |= PCRE_EXTRA; break;
+             default:
+             *errorptr = ERR12;
+             goto FAILED;
+             }
+           }
+         /* Set up the changed option bits, but don't change anything yet. */
+         newoptions = (options | set) & (~unset);
+         /* If the options ended with ')' this is not the start of a nested
+         group with option changes, so the options change at this level. At top
+         level there is nothing else to be done (the options will in fact have
+         been set from the start of compiling as a result of the first pass) but
+         at an inner level we must compile code to change the ims options if
+         necessary, and pass the new setting back so that it can be put at the
+         start of any following branches, and when this group ends, a resetting
+         item can be compiled. */
+         if (*ptr == ')')
+           {
+           if ((options & PCRE_INGROUP) != 0 &&
+               (options & PCRE_IMS) != (newoptions & PCRE_IMS))
+             {
+             *code++ = OP_OPT;
+             *code++ = *optchanged = newoptions & PCRE_IMS;
+             }
+           options = newoptions;  /* Change options at this level */
+           previous = NULL;       /* This item can't be repeated */
+           continue;              /* It is complete */
+           }
+         /* If the options ended with ':' we are heading into a nested group
+         with possible change of options. Such groups are non-capturing and are
+         not assertions of any kind. All we need to do is skip over the ':';
+         the newoptions value is handled below. */
+         bravalue = OP_BRA;
+         ptr++;
          }
        }
-     /* Else we have a referencing group */
+     /* Else we have a referencing group; adjust the opcode. */
      else
        {
-Line 1215 
 for (;; ptr++)
+Line 1305 
 for (;; ptr++)
        bravalue = OP_BRA + *brackets;
        }
-     /* Process nested bracketed re; at end pointer is on the bracket. We copy
+     /* Process nested bracketed re. Assertions may not be repeated, but other
-     code into a non-register variable in order to be able to pass its address
+     kinds can be. We copy code into a non-register variable in order to be able
-     because some compilers complain otherwise. */
+     to pass its address because some compilers complain otherwise. Pass in a
+     new setting for the ims options if they have changed. */
+     previous = (bravalue >= OP_ONCE)? code : NULL;
      *code = bravalue;
+     tempcode = code;
+     if (!compile_regex(
+          options | PCRE_INGROUP,       /* Set for all nested groups */
+          ((options & PCRE_IMS) != (newoptions & PCRE_IMS))?
+            newoptions & PCRE_IMS : -1, /* Pass ims options if changed */
+          brackets,                     /* Bracket level */
+          &tempcode,                    /* Where to put code (updated) */
+          &ptr,                         /* Input pointer (updated) */
+          errorptr,                     /* Where to put an error message */
+          (bravalue == OP_ASSERTBACK ||
+           bravalue == OP_ASSERTBACK_NOT), /* TRUE if back assert */
+          condref))                     /* Condition reference number */
+       goto FAILED;
+     /* At the end of compiling, code is still pointing to the start of the
+     group, while tempcode has been updated to point past the end of the group
+     and any option resetting that may follow it. The pattern pointer (ptr)
+     is on the bracket. */
+     /* If this is a conditional bracket, check that there are no more than
+     two branches in the group. */
+     if (bravalue == OP_COND)
        {
-       uschar *mcode = code;
+       int branchcount = 0;
-       if (!compile_regex(options, brackets, &mcode, &ptr, errorptr))
+       uschar *tc = code;
+       do {
+          branchcount++;
+          tc += (tc[1] << 8) | tc[2];
+          }
+       while (*tc != OP_KET);
+       if (branchcount > 2)
+         {
+         *errorptr = ERR27;
          goto FAILED;
-       code = mcode;
+         }
        }
+     /* Now update the main code pointer to the end of the group. */
+     code = tempcode;
+     /* Error if hit end of pattern */
      if (*ptr != ')')
        {
        *errorptr = ERR14;
-Line 1239 
 for (;; ptr++)
+Line 1371 
 for (;; ptr++)
      for validity in the pre-compiling pass. */
      case '\\':
-     oldptr = ptr;
+     tempptr = ptr;
      c = check_escape(&ptr, errorptr, *brackets, options, FALSE);
      /* Handle metacharacters introduced by \. For ones like \d, the ESC_ values
-Line 1253 
 for (;; ptr++)
+Line 1385 
 for (;; ptr++)
        {
        if (-c >= ESC_REF)
          {
-         int refnum = -c - ESC_REF;
-         if (*brackets < refnum)
-           {
-           *errorptr = ERR15;
-           goto FAILED;
-           }
          previous = code;
          *code++ = OP_REF;
-         *code++ = refnum;
+         *code++ = -c - ESC_REF;
          }
        else
          {
-         previous = (-c > ESC_b && -c < ESC_X)? code : NULL;
+         previous = (-c > ESC_b && -c < ESC_Z)? code : NULL;
          *code++ = -c;
          }
        continue;
-Line 1273 
 for (;; ptr++)
+Line 1399 
 for (;; ptr++)
      /* Data character: reset and fall through */
-     ptr = oldptr;
+     ptr = tempptr;
      c = '\\';
      /* Handle a run of data characters until a metacharacter is encountered.
-Line 1306 
 for (;; ptr++)
+Line 1432 
 for (;; ptr++)
        if (c == '\\')
          {
-         oldptr = ptr;
+         tempptr = ptr;
          c = check_escape(&ptr, errorptr, *brackets, options, FALSE);
-         if (c < 0) { ptr = oldptr; break; }
+         if (c < 0) { ptr = tempptr; break; }
          }
        /* Ordinary character or single-char escape */
-Line 1349 
 return FALSE;
+Line 1475 
 return FALSE;
  /* On entry, ptr is pointing past the bracket character, but on return
  it points to the closing bracket, or vertical bar, or end of string.
  The code variable is pointing at the byte into which the BRA operator has been
- stored.
+ stored. If the ims options are changed at the start (for a (?ims: group) or
+ during any branch, we need to insert an OP_OPT item at the start of every
+ following branch to ensure they get set correctly at run time, and also pass
+ the new options into every subsequent branch compile.
  Argument:
-   options   the option bits
+   options     the option bits
-   brackets  -> int containing the number of extracting brackets used
+   optchanged  new ims options to set as if (?ims) were at the start, or -1
-   codeptr   -> the address of the current code pointer
+                for no change
-   ptrptr    -> the address of the current pattern pointer
+   brackets    -> int containing the number of extracting brackets used
-   errorptr  -> pointer to error message
+   codeptr     -> the address of the current code pointer
+   ptrptr      -> the address of the current pattern pointer
+   errorptr    -> pointer to error message
+   lookbehind  TRUE if this is a lookbehind assertion
+   condref     > 0 for OPT_CREF setting at start of conditional group
- Returns:    TRUE on success
+ Returns:      TRUE on success
  */
  static BOOL
- compile_regex(int options, int *brackets, uschar **codeptr,
+ compile_regex(int options, int optchanged, int *brackets, uschar **codeptr,
-   const uschar **ptrptr, const char **errorptr)
+   const uschar **ptrptr, const char **errorptr, BOOL lookbehind, int condref)
  {
  const uschar *ptr = *ptrptr;
  uschar *code = *codeptr;
+ uschar *last_branch = code;
  uschar *start_bracket = code;
+ uschar *reverse_count = NULL;
+ int oldoptions = options & PCRE_IMS;
+ code += 3;
+ /* At the start of a reference-based conditional group, insert the reference
+ number as an OP_CREF item. */
+ if (condref > 0)
+   {
+   *code++ = OP_CREF;
+   *code++ = condref;
+   }
+ /* Loop for each alternative branch */
  for (;;)
    {
    int length;
-   uschar *last_branch = code;
-   code += 3;
+   /* Handle change of options */
-   if (!compile_branch(options, brackets, &code, &ptr, errorptr))
+   if (optchanged >= 0)
+     {
+     *code++ = OP_OPT;
+     *code++ = optchanged;
+     options = (options & ~PCRE_IMS) | optchanged;
+     }
+   /* Set up dummy OP_REVERSE if lookbehind assertion */
+   if (lookbehind)
+     {
+     *code++ = OP_REVERSE;
+     reverse_count = code;
+     *code++ = 0;
+     *code++ = 0;
+     }
+   /* Now compile the branch */
+   if (!compile_branch(options, brackets, &code, &ptr, errorptr, &optchanged))
      {
      *ptrptr = ptr;
      return FALSE;
-Line 1387 
 for (;;)
+Line 1555 
 for (;;)
    last_branch[1] = length >> 8;
    last_branch[2] = length & 255;
+   /* If lookbehind, check that this branch matches a fixed-length string,
+   and put the length into the OP_REVERSE item. Temporarily mark the end of
+   the branch with OP_END. */
+   if (lookbehind)
+     {
+     *code = OP_END;
+     length = find_fixedlength(last_branch);
+     DPRINTF(("fixed length = %d\n", length));
+     if (length < 0)
+       {
+       *errorptr = ERR25;
+       *ptrptr = ptr;
+       return FALSE;
+       }
+     reverse_count[0] = (length >> 8);
+     reverse_count[1] = length & 255;
+     }
    /* Reached end of expression, either ')' or end of pattern. Insert a
    terminating ket and the length of the whole bracketed item, and return,
-   leaving the pointer at the terminating char. */
+   leaving the pointer at the terminating char. If any of the ims options
+   were changed inside the group, compile a resetting op-code following. */
    if (*ptr != '|')
      {
-Line 1397 
 for (;;)
+Line 1585 
 for (;;)
      *code++ = OP_KET;
      *code++ = length >> 8;
      *code++ = length & 255;
+     if (optchanged >= 0)
+       {
+       *code++ = OP_OPT;
+       *code++ = oldoptions;
+       }
      *codeptr = code;
      *ptrptr = ptr;
      return TRUE;
-Line 1405 
 for (;;)
+Line 1598 
 for (;;)
    /* Another branch follows; insert an "or" node and advance the pointer. */
    *code = OP_ALT;
+   last_branch = code;
+   code += 3;
    ptr++;
    }
  /* Control never reaches here */
-Line 1412 
 for (;;)
+Line 1607 
 for (;;)
+ /*************************************************
+ *      Find first significant op code            *
+ *************************************************/
+ /* This is called by several functions that scan a compiled expression looking
+ for a fixed first character, or an anchoring op code etc. It skips over things
+ that do not influence this. For one application, a change of caseless option is
+ important.
+ Arguments:
+   code       pointer to the start of the group
+   options    pointer to external options
+   optbit     the option bit whose changing is significant, or
+              zero if none are
+   optstop    TRUE to return on option change, otherwise change the options
+                value and continue
+ Returns:     pointer to the first significant opcode
+ */
+ static const uschar*
+ first_significant_code(const uschar *code, int *options, int optbit,
+   BOOL optstop)
+ {
+ for (;;)
+   {
+   switch ((int)*code)
+     {
+     case OP_OPT:
+     if (optbit > 0 && ((int)code[1] & optbit) != (*options & optbit))
+       {
+       if (optstop) return code;
+       *options = (int)code[1];
+       }
+     code += 2;
+     break;
+     case OP_CREF:
+     code += 2;
+     break;
+     case OP_ASSERT_NOT:
+     case OP_ASSERTBACK:
+     case OP_ASSERTBACK_NOT:
+     do code += (code[1] << 8) + code[2]; while (*code == OP_ALT);
+     code += 3;
+     break;
+     default:
+     return code;
+     }
+   }
+ /* Control never reaches here */
+ }
  /*************************************************
  *          Check for anchored expression         *
  *************************************************/
-Line 1426 
 A branch is also implicitly anchored if
+Line 1680 
 A branch is also implicitly anchored if
  the rest of the pattern at all possible matching points, so there is no point
  trying them again.
- Argument:  points to start of expression (the bracket)
+ Arguments:
- Returns:   TRUE or FALSE
+   code       points to start of expression (the bracket)
+   options    points to the options setting
+ Returns:     TRUE or FALSE
  */
  static BOOL
- is_anchored(register const uschar *code, BOOL multiline)
+ is_anchored(register const uschar *code, int *options)
  {
  do {
-    int op = (int)code[3];
+    const uschar *scode = first_significant_code(code + 3, options,
-    if (op >= OP_BRA || op == OP_ASSERT || op == OP_ONCE)
+      PCRE_MULTILINE, FALSE);
-      { if (!is_anchored(code+3, multiline)) return FALSE; }
+    register int op = *scode;
+    if (op >= OP_BRA || op == OP_ASSERT || op == OP_ONCE || op == OP_COND)
+      { if (!is_anchored(scode, options)) return FALSE; }
     else if (op == OP_TYPESTAR || op == OP_TYPEMINSTAR)
-      { if (code[4] != OP_ANY) return FALSE; }
+      { if (scode[1] != OP_ANY) return FALSE; }
-    else if (op != OP_SOD && (multiline || op != OP_CIRC)) return FALSE;
+    else if (op != OP_SOD &&
+            ((*options & PCRE_MULTILINE) != 0 || op != OP_CIRC))
+      return FALSE;
     code += (code[1] << 8) + code[2];
     }
  while (*code == OP_ALT);
-Line 1463 
 static BOOL
+Line 1724 
 static BOOL
  is_startline(const uschar *code)
  {
  do {
-    if ((int)code[3] >= OP_BRA || code[3] == OP_ASSERT)
+    const uschar *scode = first_significant_code(code + 3, NULL, 0, FALSE);
-      { if (!is_startline(code+3)) return FALSE; }
+    register int op = *scode;
-    else if (code[3] != OP_CIRC) return FALSE;
+    if (op >= OP_BRA || op == OP_ASSERT || op == OP_ONCE || op == OP_COND)
+      { if (!is_startline(scode)) return FALSE; }
+    else if (op != OP_CIRC) return FALSE;
     code += (code[1] << 8) + code[2];
     }
  while (*code == OP_ALT);
-Line 1484 
 Consider each alternative branch. If the
+Line 1747 
 Consider each alternative branch. If the
  a bracket all of whose alternatives start with the same char (recurse ad lib),
  then we return that char, otherwise -1.
- Argument:  points to start of expression (the bracket)
+ Arguments:
- Returns:   -1 or the fixed first char
+   code       points to start of expression (the bracket)
+   options    pointer to the options (used to check casing changes)
+ Returns:     -1 or the fixed first char
  */
  static int
- find_firstchar(uschar *code)
+ find_firstchar(const uschar *code, int *options)
  {
  register int c = -1;
- do
+ do {
-   {
+    int d;
-   register int charoffset = 4;
+    const uschar *scode = first_significant_code(code + 3, options,
+      PCRE_CASELESS, TRUE);
-   if ((int)code[3] >= OP_BRA || code[3] == OP_ASSERT)
+    register int op = *scode;
-     {
-     register int d;
+    if (op >= OP_BRA) op = OP_BRA;
-     if ((d = find_firstchar(code+3)) < 0) return -1;
-     if (c < 0) c = d; else if (c != d) return -1;
+    switch(op)
-     }
+      {
+      default:
-   else switch(code[3])
+      return -1;
-     {
-     default:
+      case OP_BRA:
-     return -1;
+      case OP_ASSERT:
+      case OP_ONCE:
-     case OP_EXACT:       /* Fall through */
+      case OP_COND:
-     charoffset++;
+      if ((d = find_firstchar(scode, options)) < 0) return -1;
+      if (c < 0) c = d; else if (c != d) return -1;
-     case OP_CHARS:       /* Fall through */
+      break;
-     charoffset++;
+      case OP_EXACT:       /* Fall through */
+      scode++;
+      case OP_CHARS:       /* Fall through */
+      scode++;
+      case OP_PLUS:
+      case OP_MINPLUS:
+      if (c < 0) c = scode[1]; else if (c != scode[1]) return -1;
+      break;
+      }
-     case OP_PLUS:
+    code += (code[1] << 8) + code[2];
-     case OP_MINPLUS:
+    }
-     if (c < 0) c = code[charoffset]; else if (c != code[charoffset]) return -1;
-     break;
-     }
-   code += (code[1] << 8) + code[2];
-   }
  while (*code == OP_ALT);
  return c;
  }
  /*************************************************
  *        Compile a Regular Expression            *
  *************************************************/
-Line 1549 
 pcre_compile(const char *pattern, int op
+Line 1823 
 pcre_compile(const char *pattern, int op
    int *erroroffset)
  {
  real_pcre *re;
- int spaces = 0;
  int length = 3;      /* For initial BRA plus length */
  int runlength;
  int c, size;
  int bracount = 0;
- int brastack[200];
  int top_backref = 0;
+ int branch_extra = 0;
+ int branch_newextra;
  unsigned int brastackptr = 0;
  uschar *code;
  const uschar *ptr;
+ int brastack[BRASTACK_SIZE];
+ uschar bralenstack[BRASTACK_SIZE];
  #ifdef DEBUG
  uschar *code_base, *code_end;
-Line 1601 
 while ((c = *(++ptr)) != 0)
+Line 1877 
 while ((c = *(++ptr)) != 0)
    int min, max;
    int class_charcount;
-   if ((pcre_ctypes[c] & ctype_space) != 0)
+   if ((options & PCRE_EXTENDED) != 0)
-     {
-     if ((options & PCRE_EXTENDED) != 0) continue;
-     spaces++;
-     }
-   if (c == '#' && (options & PCRE_EXTENDED) != 0)
      {
-     while ((c = *(++ptr)) != 0 && c != '\n');
+     if ((pcre_ctypes[c] & ctype_space) != 0) continue;
-     continue;
+     if (c == '#')
+       {
+       while ((c = *(++ptr)) != 0 && c != '\n');
+       continue;
+       }
      }
    switch(c)
-Line 1684 
 while ((c = *(++ptr)) != 0)
+Line 1958 
 while ((c = *(++ptr)) != 0)
      if (ptr[1] == '?') ptr++;
      continue;
-     /* An alternation contains an offset to the next branch or ket. */
+     /* An alternation contains an offset to the next branch or ket. If any ims
+     options changed in the previous branch(es), and/or if we are in a
+     lookbehind assertion, extra space will be needed at the start of the
+     branch. This is handled by branch_extra. */
      case '|':
-     length += 3;
+     length += 3 + branch_extra;
      continue;
      /* A character class uses 33 characters. Don't worry about character types
-Line 1733 
 while ((c = *(++ptr)) != 0)
+Line 2011 
 while ((c = *(++ptr)) != 0)
      /* Brackets may be genuine groups or special things */
      case '(':
+     branch_newextra = 0;
-     /* Handle special forms of bracket, which all start (? */
-     if (ptr[1] == '?') switch (c = ptr[2])
-       {
-       /* Skip over comments entirely */
-       case '#':
-       ptr += 3;
-       while (*ptr != 0 && *ptr != ')') ptr++;
-       if (*ptr == 0)
-         {
-         *errorptr = ERR18;
-         goto PCRE_ERROR_RETURN;
-         }
-       continue;
-       /* Non-referencing groups and lookaheads just move the pointer on, and
+     /* Handle special forms of bracket, which all start (? */
-       then behave like a non-special bracket, except that they don't increment
-       the count of extracting brackets. */
-       case ':':
-       case '=':
-       case '!':
-       ptr += 2;
-       break;
-       /* Ditto for the "once only" bracket, allowed only if the extra bit
+     if (ptr[1] == '?')
-       is set. */
+       {
+       int set, unset;
+       int *optset;
-       case '>':
+       switch (c = ptr[2])
-       if ((options & PCRE_EXTRA) != 0)
          {
+         /* Skip over comments entirely */
+         case '#':
+         ptr += 3;
+         while (*ptr != 0 && *ptr != ')') ptr++;
+         if (*ptr == 0)
+           {
+           *errorptr = ERR18;
+           goto PCRE_ERROR_RETURN;
+           }
+         continue;
+         /* Non-referencing groups and lookaheads just move the pointer on, and
+         then behave like a non-special bracket, except that they don't increment
+         the count of extracting brackets. Ditto for the "once only" bracket,
+         which is in Perl from version 5.005. */
+         case ':':
+         case '=':
+         case '!':
+         case '>':
          ptr += 2;
          break;
-         }
-       /* Else fall through */
-       /* Else loop setting valid options until ) is met. Anything else is an
+         /* Lookbehinds are in Perl from version 5.005 */
-       error. */
-       default:
+         case '<':
-       ptr += 2;
+         if (ptr[3] == '=' || ptr[3] == '!')
-       for (;; ptr++)
-         {
-         if ((c = *ptr) == 'i')
-           {
-           options |= PCRE_CASELESS;
-           continue;
-           }
-         else if ((c = *ptr) == 'm')
            {
-           options |= PCRE_MULTILINE;
+           ptr += 3;
-           continue;
+           branch_newextra = 3;
+           length += 3;         /* For the first branch */
+           break;
            }
-         else if (c == 's')
+         *errorptr = ERR24;
-           {
+         goto PCRE_ERROR_RETURN;
-           options |= PCRE_DOTALL;
-           continue;
+         /* Conditionals are in Perl from version 5.005. The bracket must either
+         be followed by a number (for bracket reference) or by an assertion
+         group. */
+         case '(':
+         if ((pcre_ctypes[ptr[3]] & ctype_digit) != 0)
+           {
+           ptr += 4;
+           length += 2;
+           while ((pcre_ctypes[*ptr] & ctype_digit) != 0) ptr++;
+           if (*ptr != ')')
+             {
+             *errorptr = ERR26;
+             goto PCRE_ERROR_RETURN;
+             }
            }
-         else if (c == 'x')
+         else   /* An assertion must follow */
            {
-           options |= PCRE_EXTENDED;
+           ptr++;   /* Can treat like ':' as far as spacing is concerned */
-           length -= spaces;          /* Already counted spaces */
-           continue;
+           if (ptr[2] != '?' || strchr("=!<", ptr[3]) == NULL)
+             {
+             ptr += 2;    /* To get right offset in message */
+             *errorptr = ERR28;
+             goto PCRE_ERROR_RETURN;
+             }
            }
-         else if (c == 'X')
+         break;
+         /* Else loop checking valid options until ) is met. Anything else is an
+         error. If we are without any brackets, i.e. at top level, the settings
+         act as if specified in the options, so massage the options immediately.
+         This is for backward compatibility with Perl 5.004. */
+         default:
+         set = unset = 0;
+         optset = &set;
+         ptr += 2;
+         for (;; ptr++)
            {
-           options |= PCRE_EXTRA;
+           c = *ptr;
-           continue;
+           switch (c)
+             {
+             case 'i':
+             *optset |= PCRE_CASELESS;
+             continue;
+             case 'm':
+             *optset |= PCRE_MULTILINE;
+             continue;
+             case 's':
+             *optset |= PCRE_DOTALL;
+             continue;
+             case 'x':
+             *optset |= PCRE_EXTENDED;
+             continue;
+             case 'X':
+             *optset |= PCRE_EXTRA;
+             continue;
+             case 'U':
+             *optset |= PCRE_UNGREEDY;
+             continue;
+             case '-':
+             optset = &unset;
+             continue;
+             /* A termination by ')' indicates an options-setting-only item;
+             this is global at top level; otherwise nothing is done here and
+             it is handled during the compiling process on a per-bracket-group
+             basis. */
+             case ')':
+             if (brastackptr == 0)
+               {
+               options = (options | set) & (~unset);
+               set = unset = 0;     /* To save length */
+               }
+             /* Fall through */
+             /* A termination by ':' indicates the start of a nested group with
+             the given options set. This is again handled at compile time, but
+             we must allow for compiled space if any of the ims options are
+             set. We also have to allow for resetting space at the end of
+             the group, which is why 4 is added to the length and not just 2.
+             If there are several changes of options within the same group, this
+             will lead to an over-estimate on the length, but this shouldn't
+             matter very much. We also have to allow for resetting options at
+             the start of any alternations, which we do by setting
+             branch_newextra to 2. */
+             case ':':
+             if (((set|unset) & PCRE_IMS) != 0)
+               {
+               length += 4;
+               branch_newextra = 2;
+               }
+             goto END_OPTIONS;
+             /* Unrecognized option character */
+             default:
+             *errorptr = ERR12;
+             goto PCRE_ERROR_RETURN;
+             }
            }
-         else if (c == 'U')
+         /* If we hit a closing bracket, that's it - this is a freestanding
+         option-setting. We need to ensure that branch_extra is updated if
+         necessary. The only values branch_newextra can have here are 0 or 2.
+         If the value is 2, then branch_extra must either be 2 or 5, depending
+         on whether this is a lookbehind group or not. */
+         END_OPTIONS:
+         if (c == ')')
            {
-           options |= PCRE_UNGREEDY;
+           if (branch_newextra == 2 && (branch_extra == 0 || branch_extra == 3))
+             branch_extra += branch_newextra;
            continue;
            }
-         else if (c == ')') break;
-         *errorptr = ERR12;
+         /* If options were terminated by ':' control comes here. Fall through
-         goto PCRE_ERROR_RETURN;
+         to handle the group below. */
          }
-       continue;                      /* End of this bracket handling */
        }
      /* Extracting brackets must be counted so we can process escapes in a
-Line 1823 
 while ((c = *(++ptr)) != 0)
+Line 2196 
 while ((c = *(++ptr)) != 0)
      else bracount++;
      /* Non-special forms of bracket. Save length for computing whole length
-     at end if there's a repeat that requires duplication of the group. */
+     at end if there's a repeat that requires duplication of the group. Also
+     save the current value of branch_extra, and start the new group with
+     the new value. If non-zero, this will either be 2 for a (?imsx: group, or 3
+     for a lookbehind assertion. */
      if (brastackptr >= sizeof(brastack)/sizeof(int))
        {
-Line 1831 
 while ((c = *(++ptr)) != 0)
+Line 2207 
 while ((c = *(++ptr)) != 0)
        goto PCRE_ERROR_RETURN;
        }
+     bralenstack[brastackptr] = branch_extra;
+     branch_extra = branch_newextra;
      brastack[brastackptr++] = length;
      length += 3;
      continue;
-Line 1838 
 while ((c = *(++ptr)) != 0)
+Line 2217 
 while ((c = *(++ptr)) != 0)
      /* Handle ket. Look for subsequent max/min; for certain sets of values we
      have to replicate this bracket up to that many times. If brastackptr is
 this is an unmatched bracket which will generate an error, but take care
-     not to try to access brastack[-1]. */
+     not to try to access brastack[-1] when computing the length and restoring
+     the branch_extra value. */
      case ')':
      length += 3;
        {
        int minval = 1;
        int maxval = 1;
-       int duplength = (brastackptr > 0)? length - brastack[--brastackptr] : 0;
+       int duplength;
+       if (brastackptr > 0)
+         {
+         duplength = length - brastack[--brastackptr];
+         branch_extra = bralenstack[brastackptr];
+         }
+       else duplength = 0;
        /* Leave ptr at the final char; for read_repeat_counts this happens
        automatically; for the others we need an increment. */
-Line 1881 
 while ((c = *(++ptr)) != 0)
+Line 2268 
 while ((c = *(++ptr)) != 0)
      runlength = 0;
      do
        {
-       if ((pcre_ctypes[c] & ctype_space) != 0)
+       if ((options & PCRE_EXTENDED) != 0)
-         {
-         if ((options & PCRE_EXTENDED) != 0) continue;
-         spaces++;
-         }
-       if (c == '#' && (options & PCRE_EXTENDED) != 0)
          {
-         while ((c = *(++ptr)) != 0 && c != '\n');
+         if ((pcre_ctypes[c] & ctype_space) != 0) continue;
-         continue;
+         if (c == '#')
+           {
+           while ((c = *(++ptr)) != 0 && c != '\n');
+           continue;
+           }
          }
        /* Backslash may introduce a data char or a metacharacter; stop the
-Line 1955 
 ptr = (const uschar *)pattern;
+Line 2340 
 ptr = (const uschar *)pattern;
  code = re->code;
  *code = OP_BRA;
  bracount = 0;
- (void)compile_regex(options, &bracount, &code, &ptr, errorptr);
+ (void)compile_regex(options, -1, &bracount, &code, &ptr, errorptr, FALSE, -1);
  re->top_bracket = bracount;
  re->top_backref = top_backref;
-Line 1972 
 if debugging, leave the test till after
+Line 2357 
 if debugging, leave the test till after
  if (code - re->code > length) *errorptr = ERR23;
  #endif
+ /* Give an error if there's back reference to a non-existent capturing
+ subpattern. */
+ if (top_backref > re->top_bracket) *errorptr = ERR15;
  /* Failed to compile */
  if (*errorptr != NULL)
-Line 1990 
 to set the PCRE_STARTLINE flag if all br
+Line 2380 
 to set the PCRE_STARTLINE flag if all br
  if ((options & PCRE_ANCHORED) == 0)
    {
-   if (is_anchored(re->code, (options & PCRE_MULTILINE) != 0))
+   int temp_options = options;
+   if (is_anchored(re->code, &temp_options))
      re->options |= PCRE_ANCHORED;
    else
      {
-     int ch = find_firstchar(re->code);
+     int ch = find_firstchar(re->code, &temp_options);
      if (ch >= 0)
        {
        re->first_char = ch;
-Line 2009 
 if ((options & PCRE_ANCHORED) == 0)
+Line 2400 
 if ((options & PCRE_ANCHORED) == 0)
  #ifdef DEBUG
- printf("Length = %d top_bracket = %d top_backref=%d\n",
+ printf("Length = %d top_bracket = %d top_backref = %d\n",
    length, re->top_bracket, re->top_backref);
  if (re->options != 0)
-Line 2048 
 while (code < code_end)
+Line 2439 
 while (code < code_end)
    else switch(*code)
      {
+     case OP_OPT:
+     printf(" %.2x %s", code[1], OP_names[*code]);
+     code++;
+     break;
+     case OP_COND:
+     printf("%3d Cond", (code[1] << 8) + code[2]);
+     code += 2;
+     break;
+     case OP_CREF:
+     printf(" %.2d %s", code[1], OP_names[*code]);
+     code++;
+     break;
      case OP_CHARS:
      charlength = *(++code);
      printf("%3d ", charlength);
-Line 2061 
 while (code < code_end)
+Line 2467 
 while (code < code_end)
      case OP_KET:
      case OP_ASSERT:
      case OP_ASSERT_NOT:
+     case OP_ASSERTBACK:
+     case OP_ASSERTBACK_NOT:
      case OP_ONCE:
      printf("%3d %s", (code[1] << 8) + code[2], OP_names[*code]);
      code += 2;
      break;
+     case OP_REVERSE:
+     printf("%3d %s", (code[1] << 8) + code[2], OP_names[*code]);
+     code += 2;
+     break;
      case OP_STAR:
      case OP_MINSTAR:
      case OP_PLUS:
-Line 2139 
 while (code < code_end)
+Line 2552 
 while (code < code_end)
      goto CLASS_REF_REPEAT;
      case OP_CLASS:
-     case OP_NEGCLASS:
        {
        int i, min, max;
+       code++;
-       if (*code++ == OP_CLASS) printf("    [");
+       printf("    [");
-         else printf("   ^[");
        for (i = 0; i < 256; i++)
          {
-Line 2269 
 return FALSE;
+Line 2680 
 return FALSE;
  *          Match a back-reference                *
  *************************************************/
- /* If a back reference hasn't been set, the match fails.
+ /* If a back reference hasn't been set, the length that is passed is greater
+ than the number of characters left in the string, so the match fails.
  Arguments:
-   number      reference number
+   offset      index into the offset vector
    eptr        points into the subject
    length      length to be matched
    md          points to match data block
+   ims         the ims flags
  Returns:      TRUE if matched
  */
  static BOOL
- match_ref(int number, register const uschar *eptr, int length, match_data *md)
+ match_ref(int offset, register const uschar *eptr, int length, match_data *md,
+   int ims)
  {
- const uschar *p = md->start_subject + md->offset_vector[number];
+ const uschar *p = md->start_subject + md->offset_vector[offset];
  #ifdef DEBUG
  if (eptr >= md->end_subject)
-Line 2300 
 printf("\n");
+Line 2714 
 printf("\n");
  /* Always fail if not enough characters left */
- if (length > md->end_subject - p) return FALSE;
+ if (length > md->end_subject - eptr) return FALSE;
  /* Separate the caselesss case for speed */
- if (md->caseless)
+ if ((ims & PCRE_CASELESS) != 0)
    { while (length-- > 0) if (pcre_lcc[*p++] != pcre_lcc[*eptr++]) return FALSE; }
  else
    { while (length-- > 0) if (*p++ != *eptr++) return FALSE; }
-Line 2318 
 return TRUE;
+Line 2732 
 return TRUE;
  *         Match from current position            *
  *************************************************/
- /* On entry ecode points to the first opcode, and eptr to the first character.
+ /* On entry ecode points to the first opcode, and eptr to the first character
+ in the subject string, while eptrb holds the value of eptr at the start of the
+ last bracketed group - used for breaking infinite loops matching zero-length
+ strings.
  Arguments:
     eptr        pointer in subject
     ecode       position in code
     offset_top  current top pointer
     md          pointer to "static" info for the match
+    ims         current /i, /m, and /s options
+    condassert  TRUE if called to check a condition assertion
+    eptrb       eptr at start of last bracket
  Returns:       TRUE if matched
  */
  static BOOL
- match(register const uschar *eptr, register const uschar *ecode, int offset_top,
+ match(register const uschar *eptr, register const uschar *ecode,
-   match_data *md)
+   int offset_top, match_data *md, int ims, BOOL condassert, const uschar *eptrb)
  {
+ int original_ims = ims;   /* Save for resetting on ')' */
  for (;;)
    {
+   int op = (int)*ecode;
    int min, max, ctype;
    register int i;
    register int c;
    BOOL minimize = FALSE;
-   /* Opening bracket. Check the alternative branches in turn, failing if none
+   /* Opening capturing bracket. If there is space in the offset vector, save
-   match. We have to set the start offset if required and there is space
+   the current subject position in the working slot at the top of the vector. We
-   in the offset vector so that it is available for subsequent back references
+   mustn't change the current values of the data slot, because they may be set
-   if the bracket matches. However, if the bracket fails, we must put back the
+   from a previous iteration of this group, and be referred to by a reference
-   previous value of both offsets in case they were set by a previous copy of
+   inside the group.
-   the same bracket. Don't worry about setting the flag for the error case here;
-   that is handled in the code for KET. */
-   if ((int)*ecode >= OP_BRA)
+   If the bracket fails to match, we need to restore this value and also the
+   values of the final offsets, in case they were set by a previous iteration of
+   the same bracket.
+   If there isn't enough space in the offset vector, treat this as if it were a
+   non-capturing bracket. Don't worry about setting the flag for the error case
+   here; that is handled in the code for KET. */
+   if (op > OP_BRA)
      {
-     int number = (*ecode - OP_BRA) << 1;
+     int number = op - OP_BRA;
-     int save_offset1 = 0, save_offset2 = 0;
+     int offset = number << 1;
-     DPRINTF(("start bracket %d\n", number/2));
+     DPRINTF(("start bracket %d\n", number));
-     if (number > 0 && number < md->offset_end)
+     if (offset < md->offset_max)
        {
-       save_offset1 = md->offset_vector[number];
+       int save_offset1 = md->offset_vector[offset];
-       save_offset2 = md->offset_vector[number+1];
+       int save_offset2 = md->offset_vector[offset+1];
-       md->offset_vector[number] = eptr - md->start_subject;
+       int save_offset3 = md->offset_vector[md->offset_end - number];
+       DPRINTF(("saving %d %d %d\n", save_offset1, save_offset2, save_offset3));
+       md->offset_vector[md->offset_end - number] = eptr - md->start_subject;
+       do
+         {
+         if (match(eptr, ecode+3, offset_top, md, ims, FALSE, eptr)) return TRUE;
+         ecode += (ecode[1] << 8) + ecode[2];
+         }
+       while (*ecode == OP_ALT);
-       DPRINTF(("saving %d %d\n", save_offset1, save_offset2));
+       DPRINTF(("bracket %d failed\n", number));
+       md->offset_vector[offset] = save_offset1;
+       md->offset_vector[offset+1] = save_offset2;
+       md->offset_vector[md->offset_end - number] = save_offset3;
+       return FALSE;
        }
-     /* Recurse for all the alternatives. */
+     /* Insufficient room for saving captured contents */
+     else op = OP_BRA;
+     }
+   /* Other types of node can be handled by a switch */
+   switch(op)
+     {
+     case OP_BRA:     /* Non-capturing bracket: optimized */
+     DPRINTF(("start bracket 0\n"));
      do
        {
-       if (match(eptr, ecode+3, offset_top, md)) return TRUE;
+       if (match(eptr, ecode+3, offset_top, md, ims, FALSE, eptr)) return TRUE;
        ecode += (ecode[1] << 8) + ecode[2];
        }
      while (*ecode == OP_ALT);
+     DPRINTF(("bracket 0 failed\n"));
+     return FALSE;
+     /* Conditional group: compilation checked that there are no more than
+     two branches. If the condition is false, skipping the first branch takes us
+     past the end if there is only one branch, but that's OK because that is
+     exactly what going to the ket would do. */
+     case OP_COND:
+     if (ecode[3] == OP_CREF)         /* Condition is extraction test */
+       {
+       int offset = ecode[4] << 1;    /* Doubled reference number */
+       return match(eptr,
+         ecode + ((offset < offset_top && md->offset_vector[offset] >= 0)?
+: 3 + (ecode[1] << 8) + ecode[2]),
+         offset_top, md, ims, FALSE, eptr);
+       }
-     DPRINTF(("bracket %d failed\n", number/2));
+     /* The condition is an assertion. Call match() to evaluate it - setting
+     the final argument TRUE causes it to stop at the end of an assertion. */
-     if (number > 0 && number < md->offset_end)
+     else
        {
-       md->offset_vector[number] = save_offset1;
+       if (match(eptr, ecode+3, offset_top, md, ims, TRUE, NULL))
-       md->offset_vector[number+1] = save_offset2;
+         {
+         ecode += 3 + (ecode[4] << 8) + ecode[5];
+         while (*ecode == OP_ALT) ecode += (ecode[1] << 8) + ecode[2];
+         }
+       else ecode += (ecode[1] << 8) + ecode[2];
+       return match(eptr, ecode+3, offset_top, md, ims, FALSE, eptr);
        }
+     /* Control never reaches here */
-     return FALSE;
+     /* Skip over conditional reference data if encountered (should not be) */
-     }
-   /* Other types of node can be handled by a switch */
+     case OP_CREF:
+     ecode += 2;
+     break;
+     /* End of the pattern */
-   switch(*ecode)
-     {
      case OP_END:
      md->end_match_ptr = eptr;          /* Record where we ended */
      md->end_offset_top = offset_top;   /* and how many extracts were taken */
      return TRUE;
-     /* The equivalent of Prolog's "cut" - if the rest doesn't match, the
+     /* Change option settings */
-     whole thing doesn't match, so we have to get out via a longjmp(). */
-     case OP_CUT:
+     case OP_OPT:
-     if (match(eptr, ecode+1, offset_top, md)) return TRUE;
+     ims = ecode[1];
-     longjmp(md->fail_env, 1);
+     ecode += 2;
+     DPRINTF(("ims set to %02x\n", ims));
+     break;
      /* Assertion brackets. Check the alternative branches in turn - the
      matching won't pass the KET for an assertion. If any one branch matches,
-     the assertion is true. */
+     the assertion is true. Lookbehind assertions have an OP_REVERSE item at the
+     start of each branch to move the current point backwards, so the code at
+     this level is identical to the lookahead case. */
      case OP_ASSERT:
+     case OP_ASSERTBACK:
      do
        {
-       if (match(eptr, ecode+3, offset_top, md)) break;
+       if (match(eptr, ecode+3, offset_top, md, ims, FALSE, NULL)) break;
        ecode += (ecode[1] << 8) + ecode[2];
        }
      while (*ecode == OP_ALT);
      if (*ecode == OP_KET) return FALSE;
+     /* If checking an assertion for a condition, return TRUE. */
+     if (condassert) return TRUE;
      /* Continue from after the assertion, updating the offsets high water
      mark, since extracts may have been taken during the assertion. */
-Line 2424 
 for (;;)
+Line 2910 
 for (;;)
      /* Negative assertion: all branches must fail to match */
      case OP_ASSERT_NOT:
+     case OP_ASSERTBACK_NOT:
      do
        {
-       if (match(eptr, ecode+3, offset_top, md)) return FALSE;
+       if (match(eptr, ecode+3, offset_top, md, ims, FALSE, NULL)) return FALSE;
        ecode += (ecode[1] << 8) + ecode[2];
        }
      while (*ecode == OP_ALT);
+     if (condassert) return TRUE;
      ecode += 3;
      continue;
+     /* Move the subject pointer back. This occurs only at the start of
+     each branch of a lookbehind assertion. If we are too close to the start to
+     move back, this match function fails. */
+     case OP_REVERSE:
+     eptr -= (ecode[1] << 8) + ecode[2];
+     if (eptr < md->start_subject) return FALSE;
+     ecode += 3;
+     break;
      /* "Once" brackets are like assertion brackets except that after a match,
      the point in the subject string is not moved back. Thus there can never be
      a move back into the brackets. Check the alternative branches in turn - the
      matching won't pass the KET for this kind of subpattern. If any one branch
-     matches, we carry on, leaving the subject pointer. */
+     matches, we carry on as at the end of a normal bracket, leaving the subject
+     pointer. */
      case OP_ONCE:
-     do
        {
-       if (match(eptr, ecode+3, offset_top, md)) break;
+       const uschar *prev = ecode;
-       ecode += (ecode[1] << 8) + ecode[2];
-       }
+       do
-     while (*ecode == OP_ALT);
+         {
-     if (*ecode == OP_KET) return FALSE;
+         if (match(eptr, ecode+3, offset_top, md, ims, FALSE, eptr)) break;
+         ecode += (ecode[1] << 8) + ecode[2];
+         }
+       while (*ecode == OP_ALT);
-     /* Continue as from after the assertion, updating the offsets high water
+       /* If hit the end of the group (which could be repeated), fail */
-     mark, since extracts may have been taken. */
-     do ecode += (ecode[1] << 8) + ecode[2]; while (*ecode == OP_ALT);
+       if (*ecode != OP_ONCE && *ecode != OP_ALT) return FALSE;
-     ecode += 3;
-     offset_top = md->end_offset_top;
+       /* Continue as from after the assertion, updating the offsets high water
-     eptr = md->end_match_ptr;
+       mark, since extracts may have been taken. */
-     continue;
+       do ecode += (ecode[1] << 8) + ecode[2]; while (*ecode == OP_ALT);
+       offset_top = md->end_offset_top;
+       eptr = md->end_match_ptr;
+       /* For a non-repeating ket, just continue at this level. This also
+       happens for a repeating ket if no characters were matched in the group.
+       This is the forcible breaking of infinite loops as implemented in Perl
+.005. If there is an options reset, it will get obeyed in the normal
+       course of events. */
+       if (*ecode == OP_KET || eptr == eptrb)
+         {
+         ecode += 3;
+         break;
+         }
+       /* The repeating kets try the rest of the pattern or restart from the
+       preceding bracket, in the appropriate order. We need to reset any options
+       that changed within the bracket before re-running it, so check the next
+       opcode. */
+       if (ecode[3] == OP_OPT)
+         {
+         ims = (ims & ~PCRE_IMS) | ecode[4];
+         DPRINTF(("ims set to %02x at group repeat\n", ims));
+         }
+       if (*ecode == OP_KETRMIN)
+         {
+         if (match(eptr, ecode+3, offset_top, md, ims, FALSE, eptr) ||
+             match(eptr, prev, offset_top, md, ims, FALSE, eptr)) return TRUE;
+         }
+       else  /* OP_KETRMAX */
+         {
+         if (match(eptr, prev, offset_top, md, ims, FALSE, eptr) ||
+             match(eptr, ecode+3, offset_top, md, ims, FALSE, eptr)) return TRUE;
+         }
+       }
+     return FALSE;
      /* An alternation is the end of a branch; scan along to find the end of the
      bracketed group and go to there. */
-Line 2473 
 for (;;)
+Line 3015 
 for (;;)
      case OP_BRAZERO:
        {
        const uschar *next = ecode+1;
-       if (match(eptr, next, offset_top, md)) return TRUE;
+       if (match(eptr, next, offset_top, md, ims, FALSE, eptr)) return TRUE;
        do next += (next[1] << 8) + next[2]; while (*next == OP_ALT);
        ecode = next + 3;
        }
-Line 2483 
 for (;;)
+Line 3025 
 for (;;)
        {
        const uschar *next = ecode+1;
        do next += (next[1] << 8) + next[2]; while (*next == OP_ALT);
-       if (match(eptr, next+3, offset_top, md)) return TRUE;
+       if (match(eptr, next+3, offset_top, md, ims, FALSE, eptr)) return TRUE;
        ecode++;
        }
-     break;;
+     break;
      /* End of a group, repeated or non-repeating. If we are at the end of
      an assertion "group", stop matching and return TRUE, but record the
-     current high water mark for use by positive assertions. */
+     current high water mark for use by positive assertions. Do this also
+     for the "once" (not-backup up) groups. */
      case OP_KET:
      case OP_KETRMIN:
      case OP_KETRMAX:
        {
-       int number;
        const uschar *prev = ecode - (ecode[1] << 8) - ecode[2];
-       if (*prev == OP_ASSERT || *prev == OP_ASSERT_NOT || *prev == OP_ONCE)
+       if (*prev == OP_ASSERT || *prev == OP_ASSERT_NOT ||
+           *prev == OP_ASSERTBACK || *prev == OP_ASSERTBACK_NOT ||
+           *prev == OP_ONCE)
          {
          md->end_match_ptr = eptr;      /* For ONCE */
          md->end_offset_top = offset_top;
          return TRUE;
          }
-       /* In all other cases we have to check the group number back at the
+       /* In all other cases except a conditional group we have to check the
-       start and if necessary complete handling an extraction by setting the
+       group number back at the start and if necessary complete handling an
-       final offset and bumping the high water mark. */
+       extraction by setting the offsets and bumping the high water mark. */
-       number = (*prev - OP_BRA) << 1;
+       if (*prev != OP_COND)
+         {
+         int number = *prev - OP_BRA;
+         int offset = number << 1;
-       DPRINTF(("end bracket %d\n", number/2));
+         DPRINTF(("end bracket %d\n", number));
-       if (number > 0)
+         if (number > 0)
-         {
-         if (number >= md->offset_end) md->offset_overflow = TRUE; else
            {
-           md->offset_vector[number+1] = eptr - md->start_subject;
+           if (offset >= md->offset_max) md->offset_overflow = TRUE; else
-           if (offset_top <= number) offset_top = number + 2;
+             {
+             md->offset_vector[offset] =
+               md->offset_vector[md->offset_end - number];
+             md->offset_vector[offset+1] = eptr - md->start_subject;
+             if (offset_top <= offset) offset_top = offset + 2;
+             }
            }
          }
-       /* For a non-repeating ket, just advance to the next node and continue at
+       /* Reset the value of the ims flags, in case they got changed during
-       this level. */
+       the group. */
+       ims = original_ims;
+       DPRINTF(("ims reset to %02x\n", ims));
-       if (*ecode == OP_KET)
+       /* For a non-repeating ket, just continue at this level. This also
+       happens for a repeating ket if no characters were matched in the group.
+       This is the forcible breaking of infinite loops as implemented in Perl
+.005. If there is an options reset, it will get obeyed in the normal
+       course of events. */
+       if (*ecode == OP_KET || eptr == eptrb)
          {
          ecode += 3;
          break;
-Line 2537 
 for (;;)
+Line 3096 
 for (;;)
        if (*ecode == OP_KETRMIN)
          {
-         if (match(eptr, ecode+3, offset_top, md) ||
+         if (match(eptr, ecode+3, offset_top, md, ims, FALSE, eptr) ||
-             match(eptr, prev, offset_top, md)) return TRUE;
+             match(eptr, prev, offset_top, md, ims, FALSE, eptr)) return TRUE;
          }
        else  /* OP_KETRMAX */
          {
-         if (match(eptr, prev, offset_top, md) ||
+         if (match(eptr, prev, offset_top, md, ims, FALSE, eptr) ||
-             match(eptr, ecode+3, offset_top, md)) return TRUE;
+             match(eptr, ecode+3, offset_top, md, ims, FALSE, eptr)) return TRUE;
          }
        }
      return FALSE;
-Line 2552 
 for (;;)
+Line 3111 
 for (;;)
      case OP_CIRC:
      if (md->notbol && eptr == md->start_subject) return FALSE;
-     if (md->multiline)
+     if ((ims & PCRE_MULTILINE) != 0)
        {
        if (eptr != md->start_subject && eptr[-1] != '\n') return FALSE;
        ecode++;
-Line 2567 
 for (;;)
+Line 3126 
 for (;;)
      ecode++;
      break;
-     /* Assert before internal newline if multiline, or before
+     /* Assert before internal newline if multiline, or before a terminating
-     a terminating newline unless endonly is set, else end of subject unless
+     newline unless endonly is set, else end of subject unless noteol is set. */
-     noteol is set. */
      case OP_DOLL:
-     if (md->noteol && eptr >= md->end_subject) return FALSE;
+     if ((ims & PCRE_MULTILINE) != 0)
-     if (md->multiline)
        {
-       if (eptr < md->end_subject && *eptr != '\n') return FALSE;
+       if (eptr < md->end_subject) { if (*eptr != '\n') return FALSE; }
+         else { if (md->noteol) return FALSE; }
        ecode++;
        break;
        }
-     else if (!md->endonly)
+     else
        {
-       if (eptr < md->end_subject - 1 ||
+       if (md->noteol) return FALSE;
-          (eptr == md->end_subject - 1 && *eptr != '\n')) return FALSE;
+       if (!md->endonly)
-       ecode++;
+         {
-       break;
+         if (eptr < md->end_subject - 1 ||
+            (eptr == md->end_subject - 1 && *eptr != '\n')) return FALSE;
+         ecode++;
+         break;
+         }
        }
      /* ... else fall through */
-     /* End of subject assertion */
+     /* End of subject assertion (\z) */
      case OP_EOD:
      if (eptr < md->end_subject) return FALSE;
      ecode++;
      break;
+     /* End of subject or ending \n assertion (\Z) */
+     case OP_EODN:
+     if (eptr < md->end_subject - 1 ||
+        (eptr == md->end_subject - 1 && *eptr != '\n')) return FALSE;
+     ecode++;
+     break;
      /* Word boundary assertions */
      case OP_NOT_WORD_BOUNDARY:
-Line 2613 
 for (;;)
+Line 3184 
 for (;;)
      /* Match a single character type; inline for speed */
      case OP_ANY:
-     if (!md->dotall && eptr < md->end_subject && *eptr == '\n') return FALSE;
+     if ((ims & PCRE_DOTALL) == 0 && eptr < md->end_subject && *eptr == '\n')
+       return FALSE;
      if (eptr++ >= md->end_subject) return FALSE;
      ecode++;
      break;
-Line 2665 
 for (;;)
+Line 3237 
 for (;;)
      case OP_REF:
        {
        int length;
-       int number = ecode[1] << 1;                /* Doubled reference number */
+       int offset = ecode[1] << 1;                /* Doubled reference number */
        ecode += 2;                                /* Advance past the item */
-       if (number >= offset_top || md->offset_vector[number] < 0)
+       /* If the reference is unset, set the length to be longer than the amount
-         {
+       of subject left; this ensures that every attempt at a match fails. We
-         md->errorcode = PCRE_ERROR_BADREF;
+       can't just fail here, because of the possibility of quantifiers with zero
-         return FALSE;
+       minima. */
-         }
+       length = (offset >= offset_top || md->offset_vector[offset] < 0)?
+         md->end_subject - eptr + 1 :
+         md->offset_vector[offset+1] - md->offset_vector[offset];
-       length = md->offset_vector[number+1] - md->offset_vector[number];
+       /* Set up for repetition, or handle the non-repeated case */
        switch (*ecode)
          {
-Line 2701 
 for (;;)
+Line 3276 
 for (;;)
          break;
          default:               /* No repeat follows */
-         if (!match_ref(number, eptr, length, md)) return FALSE;
+         if (!match_ref(offset, eptr, length, md, ims)) return FALSE;
          eptr += length;
          continue;              /* With the main loop */
          }
-Line 2717 
 for (;;)
+Line 3292 
 for (;;)
        for (i = 1; i <= min; i++)
          {
-         if (!match_ref(number, eptr, length, md)) return FALSE;
+         if (!match_ref(offset, eptr, length, md, ims)) return FALSE;
          eptr += length;
          }
-Line 2732 
 for (;;)
+Line 3307 
 for (;;)
          {
          for (i = min;; i++)
            {
-           if (match(eptr, ecode, offset_top, md)) return TRUE;
+           if (match(eptr, ecode, offset_top, md, ims, FALSE, eptrb))
-           if (i >= max || !match_ref(number, eptr, length, md))
+             return TRUE;
+           if (i >= max || !match_ref(offset, eptr, length, md, ims))
              return FALSE;
            eptr += length;
            }
-Line 2747 
 for (;;)
+Line 3323 
 for (;;)
          const uschar *pp = eptr;
          for (i = min; i < max; i++)
            {
-           if (!match_ref(number, eptr, length, md)) break;
+           if (!match_ref(offset, eptr, length, md, ims)) break;
            eptr += length;
            }
          while (eptr >= pp)
            {
-           if (match(eptr, ecode, offset_top, md)) return TRUE;
+           if (match(eptr, ecode, offset_top, md, ims, FALSE, eptrb))
+             return TRUE;
            eptr -= length;
            }
          return FALSE;
-Line 2760 
 for (;;)
+Line 3337 
 for (;;)
        }
      /* Control never gets here */
      /* Match a character class, possibly repeatedly. Look past the end of the
      item to see if there is repeat information following. Then obey similar
-     code to character type repeats - written out again for speed. If caseless
+     code to character type repeats - written out again for speed. */
-     matching was set at runtime but not at compile time, we have to check both
-     versions of a character, and we have to behave differently for positive and
-     negative classes. This is the only time where OP_CLASS and OP_NEGCLASS are
-     treated differently. */
      case OP_CLASS:
-     case OP_NEGCLASS:
        {
-       BOOL nasty_case = *ecode == OP_NEGCLASS && md->runtime_caseless;
        const uschar *data = ecode + 1;  /* Save for matching */
        ecode += 33;                     /* Advance past the item */
-Line 2810 
 for (;;)
+Line 3383 
 for (;;)
          {
          if (eptr >= md->end_subject) return FALSE;
          c = *eptr++;
+         if ((data[c/8] & (1 << (c&7))) != 0) continue;
-         /* Either not runtime caseless, or it was a positive class. For
-         runtime caseless, continue if either case is in the map. */
-         if (!nasty_case)
-           {
-           if ((data[c/8] & (1 << (c&7))) != 0) continue;
-           if (md->runtime_caseless)
-             {
-             c = pcre_fcc[c];
-             if ((data[c/8] & (1 << (c&7))) != 0) continue;
-             }
-           }
-         /* Runtime caseless and it was a negative class. Continue only if
-         both cases are in the map. */
-         else
-           {
-           if ((data[c/8] & (1 << (c&7))) == 0) return FALSE;
-           c = pcre_fcc[c];
-           if ((data[c/8] & (1 << (c&7))) != 0) continue;
-           }
          return FALSE;
          }
-Line 2849 
 for (;;)
+Line 3399 
 for (;;)
          {
          for (i = min;; i++)
            {
-           if (match(eptr, ecode, offset_top, md)) return TRUE;
+           if (match(eptr, ecode, offset_top, md, ims, FALSE, eptrb))
+             return TRUE;
            if (i >= max || eptr >= md->end_subject) return FALSE;
            c = *eptr++;
+           if ((data[c/8] & (1 << (c&7))) != 0) continue;
-           /* Either not runtime caseless, or it was a positive class. For
-           runtime caseless, continue if either case is in the map. */
-           if (!nasty_case)
-             {
-             if ((data[c/8] & (1 << (c&7))) != 0) continue;
-             if (md->runtime_caseless)
-               {
-               c = pcre_fcc[c];
-               if ((data[c/8] & (1 << (c&7))) != 0) continue;
-               }
-             }
-           /* Runtime caseless and it was a negative class. Continue only if
-           both cases are in the map. */
-           else
-             {
-             if ((data[c/8] & (1 << (c&7))) == 0) return FALSE;
-             c = pcre_fcc[c];
-             if ((data[c/8] & (1 << (c&7))) != 0) continue;
-             }
            return FALSE;
            }
          /* Control never gets here */
-Line 2890 
 for (;;)
+Line 3418 
 for (;;)
            {
            if (eptr >= md->end_subject) break;
            c = *eptr;
+           if ((data[c/8] & (1 << (c&7))) != 0) continue;
-           /* Either not runtime caseless, or it was a positive class. For
-           runtime caseless, continue if either case is in the map. */
-           if (!nasty_case)
-             {
-             if ((data[c/8] & (1 << (c&7))) != 0) continue;
-             if (md->runtime_caseless)
-               {
-               c = pcre_fcc[c];
-               if ((data[c/8] & (1 << (c&7))) != 0) continue;
-               }
-             }
-           /* Runtime caseless and it was a negative class. Continue only if
-           both cases are in the map. */
-           else
-             {
-             if ((data[c/8] & (1 << (c&7))) == 0) break;
-             c = pcre_fcc[c];
-             if ((data[c/8] & (1 << (c&7))) != 0) continue;
-             }
            break;
            }
          while (eptr >= pp)
-           if (match(eptr--, ecode, offset_top, md)) return TRUE;
+           if (match(eptr--, ecode, offset_top, md, ims, FALSE, eptrb))
+             return TRUE;
          return FALSE;
          }
        }
-Line 2945 
 for (;;)
+Line 3451 
 for (;;)
  #endif
        if (length > md->end_subject - eptr) return FALSE;
-       if (md->caseless)
+       if ((ims & PCRE_CASELESS) != 0)
          {
          while (length-- > 0) if (pcre_lcc[*ecode++] != pcre_lcc[*eptr++]) return FALSE;
          }
-Line 3002 
 for (;;)
+Line 3508 
 for (;;)
      DPRINTF(("matching %c{%d,%d} against subject %.*s\n", c, min, max,
        max, eptr));
-     if (md->caseless)
+     if ((ims & PCRE_CASELESS) != 0)
        {
        c = pcre_lcc[c];
        for (i = 1; i <= min; i++) if (c != pcre_lcc[*eptr++]) return FALSE;
-Line 3011 
 for (;;)
+Line 3517 
 for (;;)
          {
          for (i = min;; i++)
            {
-           if (match(eptr, ecode, offset_top, md)) return TRUE;
+           if (match(eptr, ecode, offset_top, md, ims, FALSE, eptrb))
+             return TRUE;
            if (i >= max || eptr >= md->end_subject || c != pcre_lcc[*eptr++])
              return FALSE;
            }
-Line 3026 
 for (;;)
+Line 3533 
 for (;;)
            eptr++;
            }
          while (eptr >= pp)
-           if (match(eptr--, ecode, offset_top, md)) return TRUE;
+           if (match(eptr--, ecode, offset_top, md, ims, FALSE, eptrb))
+             return TRUE;
          return FALSE;
          }
        /* Control never gets here */
-Line 3042 
 for (;;)
+Line 3550 
 for (;;)
          {
          for (i = min;; i++)
            {
-           if (match(eptr, ecode, offset_top, md)) return TRUE;
+           if (match(eptr, ecode, offset_top, md, ims, FALSE, eptrb))
+             return TRUE;
            if (i >= max || eptr >= md->end_subject || c != *eptr++) return FALSE;
            }
          /* Control never gets here */
-Line 3056 
 for (;;)
+Line 3565 
 for (;;)
            eptr++;
            }
          while (eptr >= pp)
-          if (match(eptr--, ecode, offset_top, md)) return TRUE;
+          if (match(eptr--, ecode, offset_top, md, ims, FALSE, eptrb))
+            return TRUE;
          return FALSE;
          }
        }
-Line 3067 
 for (;;)
+Line 3577 
 for (;;)
      case OP_NOT:
      if (eptr >= md->end_subject) return FALSE;
      ecode++;
-     if (md->caseless)
+     if ((ims & PCRE_CASELESS) != 0)
        {
        if (pcre_lcc[*ecode++] == pcre_lcc[*eptr++]) return FALSE;
        }
-Line 3127 
 for (;;)
+Line 3637 
 for (;;)
      DPRINTF(("negative matching %c{%d,%d} against subject %.*s\n", c, min, max,
        max, eptr));
-     if (md->caseless)
+     if ((ims & PCRE_CASELESS) != 0)
        {
        c = pcre_lcc[c];
        for (i = 1; i <= min; i++) if (c == pcre_lcc[*eptr++]) return FALSE;
-Line 3136 
 for (;;)
+Line 3646 
 for (;;)
          {
          for (i = min;; i++)
            {
-           if (match(eptr, ecode, offset_top, md)) return TRUE;
+           if (match(eptr, ecode, offset_top, md, ims, FALSE, eptrb))
+             return TRUE;
            if (i >= max || eptr >= md->end_subject || c == pcre_lcc[*eptr++])
              return FALSE;
            }
-Line 3151 
 for (;;)
+Line 3662 
 for (;;)
            eptr++;
            }
          while (eptr >= pp)
-           if (match(eptr--, ecode, offset_top, md)) return TRUE;
+           if (match(eptr--, ecode, offset_top, md, ims, FALSE, eptrb))
+             return TRUE;
          return FALSE;
          }
        /* Control never gets here */
-Line 3167 
 for (;;)
+Line 3679 
 for (;;)
          {
          for (i = min;; i++)
            {
-           if (match(eptr, ecode, offset_top, md)) return TRUE;
+           if (match(eptr, ecode, offset_top, md, ims, FALSE, eptrb))
+             return TRUE;
            if (i >= max || eptr >= md->end_subject || c == *eptr++) return FALSE;
            }
          /* Control never gets here */
-Line 3181 
 for (;;)
+Line 3694 
 for (;;)
            eptr++;
            }
          while (eptr >= pp)
-          if (match(eptr--, ecode, offset_top, md)) return TRUE;
+          if (match(eptr--, ecode, offset_top, md, ims, FALSE, eptrb))
+            return TRUE;
          return FALSE;
          }
        }
-Line 3231 
 for (;;)
+Line 3745 
 for (;;)
      if (min > 0) switch(ctype)
        {
        case OP_ANY:
-       if (!md->dotall)
+       if ((ims & PCRE_DOTALL) == 0)
          { for (i = 1; i <= min; i++) if (*eptr++ == '\n') return FALSE; }
        else eptr += min;
        break;
-Line 3278 
 for (;;)
+Line 3792 
 for (;;)
        {
        for (i = min;; i++)
          {
-         if (match(eptr, ecode, offset_top, md)) return TRUE;
+         if (match(eptr, ecode, offset_top, md, ims, FALSE, eptrb)) return TRUE;
          if (i >= max || eptr >= md->end_subject ||
-           !match_type(ctype, *eptr++, md->dotall))
+           !match_type(ctype, *eptr++, (ims & PCRE_DOTALL) != 0))
              return FALSE;
          }
        /* Control never gets here */
-Line 3295 
 for (;;)
+Line 3809 
 for (;;)
        switch(ctype)
          {
          case OP_ANY:
-         if (!md->dotall)
+         if ((ims & PCRE_DOTALL) == 0)
            {
            for (i = min; i < max; i++)
              {
-Line 3367 
 for (;;)
+Line 3881 
 for (;;)
          }
        while (eptr >= pp)
-         if (match(eptr--, ecode, offset_top, md)) return TRUE;
+         if (match(eptr--, ecode, offset_top, md, ims, FALSE, eptrb))
+           return TRUE;
        return FALSE;
        }
      /* Control never gets here */
-Line 3390 
 for (;;)
+Line 3905 
 for (;;)
- /*************************************************
- *         Segregate setjmp()                     *
- *************************************************/
- /* The -Wall option of gcc gives warnings for all local variables when setjmp()
- is used, even if the coding conforms to the rules of ANSI C. To avoid this, we
- hide it in a separate function. This is called only when PCRE_EXTRA is set,
- since it's needed only for the extension \X option, and with any luck, a good
- compiler will spot the tail recursion and compile it efficiently.
- Arguments:
-    eptr        pointer in subject
-    ecode       position in code
-    offset_top  current top pointer
-    md          pointer to "static" info for the match
- Returns:       TRUE if matched
- */
- static BOOL
- match_with_setjmp(const uschar *eptr, const uschar *ecode, int offset_top,
-   match_data *match_block)
- {
- return setjmp(match_block->fail_env) == 0 &&
-       match(eptr, ecode, offset_top, match_block);
- }
  /*************************************************
  *         Execute a Regular Expression           *
-Line 3448 
 pcre_exec(const pcre *external_re, const
+Line 3935 
 pcre_exec(const pcre *external_re, const
  {
  int resetcount, ocount;
  int first_char = -1;
+ int ims = 0;
  match_data match_block;
  const uschar *start_bits = NULL;
  const uschar *start_match = (const uschar *)subject;
-Line 3468 
 match_block.start_subject = (const uscha
+Line 3956 
 match_block.start_subject = (const uscha
  match_block.end_subject = match_block.start_subject + length;
  end_subject = match_block.end_subject;
- match_block.caseless  = ((re->options | options) & PCRE_CASELESS) != 0;
+ match_block.endonly = (re->options & PCRE_DOLLAR_ENDONLY) != 0;
- match_block.runtime_caseless = match_block.caseless &&
-   (re->options & PCRE_CASELESS) == 0;
- match_block.multiline = ((re->options | options) & PCRE_MULTILINE) != 0;
- match_block.dotall    = ((re->options | options) & PCRE_DOTALL) != 0;
- match_block.endonly   = ((re->options | options) & PCRE_DOLLAR_ENDONLY) != 0;
  match_block.notbol = (options & PCRE_NOTBOL) != 0;
  match_block.noteol = (options & PCRE_NOTEOL) != 0;
  match_block.errorcode = PCRE_ERROR_NOMATCH;     /* Default error */
+ /* The ims options can vary during the matching as a result of the presence
+ of (?ims) items in the pattern. They are kept in a local variable so that
+ restoring at the exit of a group is easy. */
+ ims = re->options & (PCRE_CASELESS|PCRE_MULTILINE|PCRE_DOTALL);
  /* If the expression has got more back references than the offsets supplied can
  hold, we get a temporary bit of working store to use during the matching.
  Otherwise, we can use the vector supplied, rounding down its size to a multiple
- of 2. */
+ of 3. */
- ocount = offsetcount & (-2);
+ ocount = offsetcount - (offsetcount % 3);
- if (re->top_backref > 0 && re->top_backref >= ocount/2)
+ if (re->top_backref > 0 && re->top_backref >= ocount/3)
    {
-   ocount = re->top_backref * 2 + 2;
+   ocount = re->top_backref * 3 + 3;
    match_block.offset_vector = (int *)(pcre_malloc)(ocount * sizeof(int));
    if (match_block.offset_vector == NULL) return PCRE_ERROR_NOMEMORY;
    using_temporary_offsets = TRUE;
-Line 3498 
 if (re->top_backref > 0 && re->top_backr
+Line 3987 
 if (re->top_backref > 0 && re->top_backr
  else match_block.offset_vector = offsets;
  match_block.offset_end = ocount;
+ match_block.offset_max = (2*ocount)/3;
  match_block.offset_overflow = FALSE;
  /* Compute the minimum number of offsets that we need to reset each time. Doing
-Line 3507 
 in the pattern. */
+Line 3997 
 in the pattern. */
  resetcount = 2 + re->top_bracket * 2;
  if (resetcount > offsetcount) resetcount = ocount;
- /* If MULTILINE is set at exec time but was not set at compile time, and the
- anchored flag is set, we must re-check because a setting provoked by ^ in the
- pattern is not right in multi-line mode. Calling is_anchored() again here does
- the right check, because multiline is now set. If it now yields FALSE, the
- expression must have had ^ starting some of its branches. Check to see if
- that is true for *all* branches, and if so, set the startline flag. */
- if (match_block. multiline && anchored && (re->options & PCRE_MULTILINE) == 0 &&
-     !is_anchored(re->code, match_block.multiline))
-   {
-   anchored = FALSE;
-   if (is_startline(re->code)) startline = TRUE;
-   }
  /* Set up the first character to match, if available. The first_char value is
  never set for an anchored regular expression, but the anchoring may be forced
  at run time, so we have to test for anchoring. The first char may be unset for
  an unanchored pattern, of course. If there's no first char and the pattern was
- studied, the may be a bitmap of possible first characters. However, we can
+ studied, there may be a bitmap of possible first characters. */
- use this only if the caseless state of the studying was correct. */
  if (!anchored)
    {
    if ((re->options & PCRE_FIRSTSET) != 0)
      {
      first_char = re->first_char;
-     if (match_block.caseless) first_char = pcre_lcc[first_char];
+     if ((ims & PCRE_CASELESS) != 0) first_char = pcre_lcc[first_char];
      }
    else
      if (!startline && extra != NULL &&
-       (extra->options & PCRE_STUDY_MAPPED) != 0 &&
+       (extra->options & PCRE_STUDY_MAPPED) != 0)
-       ((extra->options & PCRE_STUDY_CASELESS) != 0) == match_block.caseless)
          start_bits = extra->start_bits;
    }
-Line 3558 
 do
+Line 4032 
 do
    if (first_char >= 0)
      {
-     if (match_block.caseless)
+     if ((ims & PCRE_CASELESS) != 0)
        while (start_match < end_subject && pcre_lcc[*start_match] != first_char)
          start_match++;
      else
-Line 3599 
 do
+Line 4073 
 do
    there were too many extractions, set the return code to zero. In the case
    where we had to get some local store to hold offsets for backreferences, copy
    those back references that we can. In this case there need not be overflow
-   if certain parts of the pattern were not used.
+   if certain parts of the pattern were not used. */
-   Before starting the match, we have to set up a longjmp() target to enable
-   the "cut" operation to fail a match completely without backtracking. This
-   is done in a separate function to avoid compiler warnings. We need not do
-   it unless PCRE_EXTRA is set, since only in that case is the "cut" operation
-   enabled. */
-   if ((re->options & PCRE_EXTRA) != 0)
+   if (!match(start_match, re->code, 2, &match_block, ims, FALSE, start_match))
-     {
+     continue;
-     if (!match_with_setjmp(start_match, re->code, 2, &match_block))
-       continue;
-     }
-   else if (!match(start_match, re->code, 2, &match_block)) continue;
    /* Copy the offset information from temporary store if necessary */

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Added in v.23
 Legend:



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+Added in v.23

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