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

Diff of /code/trunk/pcre_compile.c

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-revision 544 by ph10,
Tue Jun 15 17:20:55 2010 UTC
+revision 723 by ph10,
Sat Oct  8 15:55:23 2011 UTC
 Line 6
  and semantics are as close as possible to those of the Perl 5 language.
                         Written by Philip Hazel
-            Copyright (c) 1997-2010 University of Cambridge
+            Copyright (c) 1997-2011 University of Cambridge
  -----------------------------------------------------------------------------
  Redistribution and use in source and binary forms, with or without
 Line 393 
 static const char error_texts[] =
    "internal error: previously-checked referenced subpattern not found\0"
    "DEFINE group contains more than one branch\0"
    /* 55 */
-   "repeating a DEFINE group is not allowed\0"
+   "repeating a DEFINE group is not allowed\0"  /** DEAD **/
    "inconsistent NEWLINE options\0"
    "\\g is not followed by a braced, angle-bracketed, or quoted name/number or by a plain number\0"
    "a numbered reference must not be zero\0"
 Line 408 
 static const char error_texts[] =
    "different names for subpatterns of the same number are not allowed\0"
    "(*MARK) must have an argument\0"
    "this version of PCRE is not compiled with PCRE_UCP support\0"
+   "\\c must be followed by an ASCII character\0"
+   "\\k is not followed by a braced, angle-bracketed, or quoted name\0"
    ;
  /* Table to identify digits and hex digits. This is used when compiling
-Line 544 
 static const unsigned char ebcdic_charta
+Line 546 
 static const unsigned char ebcdic_charta
  /* Definition to allow mutual recursion */
  static BOOL
-   compile_regex(int, int, uschar **, const uschar **, int *, BOOL, BOOL, int,
+   compile_regex(int, uschar **, const uschar **, int *, BOOL, BOOL, int, int,
      int *, int *, branch_chain *, compile_data *, int *);
-Line 576 
 return s;
+Line 578 
 return s;
  /*************************************************
+ *            Check for counted repeat            *
+ *************************************************/
+ /* This function is called when a '{' is encountered in a place where it might
+ start a quantifier. It looks ahead to see if it really is a quantifier or not.
+ It is only a quantifier if it is one of the forms {ddd} {ddd,} or {ddd,ddd}
+ where the ddds are digits.
+ Arguments:
+   p         pointer to the first char after '{'
+ Returns:    TRUE or FALSE
+ */
+ static BOOL
+ is_counted_repeat(const uschar *p)
+ {
+ if ((digitab[*p++] & ctype_digit) == 0) return FALSE;
+ while ((digitab[*p] & ctype_digit) != 0) p++;
+ if (*p == CHAR_RIGHT_CURLY_BRACKET) return TRUE;
+ if (*p++ != CHAR_COMMA) return FALSE;
+ if (*p == CHAR_RIGHT_CURLY_BRACKET) return TRUE;
+ if ((digitab[*p++] & ctype_digit) == 0) return FALSE;
+ while ((digitab[*p] & ctype_digit) != 0) p++;
+ return (*p == CHAR_RIGHT_CURLY_BRACKET);
+ }
+ /*************************************************
  *            Handle escapes                      *
  *************************************************/
-Line 646 
 else
+Line 681 
 else
      *errorcodeptr = ERR37;
      break;
-     /* \g must be followed by one of a number of specific things:
+     /* In a character class, \g is just a literal "g". Outside a character
+     class, \g must be followed by one of a number of specific things:
      (1) A number, either plain or braced. If positive, it is an absolute
      backreference. If negative, it is a relative backreference. This is a Perl
-Line 663 
 else
+Line 699 
 else
      the -ESC_g code (cf \k). */
      case CHAR_g:
+     if (isclass) break;
      if (ptr[1] == CHAR_LESS_THAN_SIGN || ptr[1] == CHAR_APOSTROPHE)
        {
        c = -ESC_g;
-Line 841 
 else
+Line 878 
 else
      break;
      /* For \c, a following letter is upper-cased; then the 0x40 bit is flipped.
-     This coding is ASCII-specific, but then the whole concept of \cx is
+     An error is given if the byte following \c is not an ASCII character. This
+     coding is ASCII-specific, but then the whole concept of \cx is
      ASCII-specific. (However, an EBCDIC equivalent has now been added.) */
      case CHAR_c:
-Line 851 
 else
+Line 889 
 else
        *errorcodeptr = ERR2;
        break;
        }
+ #ifndef EBCDIC    /* ASCII/UTF-8 coding */
- #ifndef EBCDIC  /* ASCII/UTF-8 coding */
+     if (c > 127)  /* Excludes all non-ASCII in either mode */
+       {
+       *errorcodeptr = ERR68;
+       break;
+       }
      if (c >= CHAR_a && c <= CHAR_z) c -= 32;
      c ^= 0x40;
- #else           /* EBCDIC coding */
+ #else             /* EBCDIC coding */
      if (c >= CHAR_a && c <= CHAR_z) c += 64;
      c ^= 0xC0;
  #endif
-Line 879 
 else
+Line 921 
 else
    }
  /* Perl supports \N{name} for character names, as well as plain \N for "not
- newline". PCRE does not support \N{name}. */
+ newline". PCRE does not support \N{name}. However, it does support
+ quantification such as \N{2,3}. */
- if (c == -ESC_N && ptr[1] == CHAR_LEFT_CURLY_BRACKET)
+ if (c == -ESC_N && ptr[1] == CHAR_LEFT_CURLY_BRACKET &&
+      !is_counted_repeat(ptr+2))
    *errorcodeptr = ERR37;
  /* If PCRE_UCP is set, we change the values for \d etc. */
-Line 991 
 return -1;
+Line 1035 
 return -1;
  /*************************************************
- *            Check for counted repeat            *
- *************************************************/
- /* This function is called when a '{' is encountered in a place where it might
- start a quantifier. It looks ahead to see if it really is a quantifier or not.
- It is only a quantifier if it is one of the forms {ddd} {ddd,} or {ddd,ddd}
- where the ddds are digits.
- Arguments:
-   p         pointer to the first char after '{'
- Returns:    TRUE or FALSE
- */
- static BOOL
- is_counted_repeat(const uschar *p)
- {
- if ((digitab[*p++] & ctype_digit) == 0) return FALSE;
- while ((digitab[*p] & ctype_digit) != 0) p++;
- if (*p == CHAR_RIGHT_CURLY_BRACKET) return TRUE;
- if (*p++ != CHAR_COMMA) return FALSE;
- if (*p == CHAR_RIGHT_CURLY_BRACKET) return TRUE;
- if ((digitab[*p++] & ctype_digit) == 0) return FALSE;
- while ((digitab[*p] & ctype_digit) != 0) p++;
- return (*p == CHAR_RIGHT_CURLY_BRACKET);
- }
- /*************************************************
  *         Read repeat counts                     *
  *************************************************/
-Line 1099 
 top-level call starts at the beginning o
+Line 1110 
 top-level call starts at the beginning o
  start at a parenthesis. It scans along a pattern's text looking for capturing
  subpatterns, and counting them. If it finds a named pattern that matches the
  name it is given, it returns its number. Alternatively, if the name is NULL, it
- returns when it reaches a given numbered subpattern. We know that if (?P< is
+ returns when it reaches a given numbered subpattern. Recursion is used to keep
- encountered, the name will be terminated by '>' because that is checked in the
+ track of subpatterns that reset the capturing group numbers - the (?| feature.
- first pass. Recursion is used to keep track of subpatterns that reset the
- capturing group numbers - the (?| feature.
+ This function was originally called only from the second pass, in which we know
+ that if (?< or (?' or (?P< is encountered, the name will be correctly
+ terminated because that is checked in the first pass. There is now one call to
+ this function in the first pass, to check for a recursive back reference by
+ name (so that we can make the whole group atomic). In this case, we need check
+ only up to the current position in the pattern, and that is still OK because
+ and previous occurrences will have been checked. To make this work, the test
+ for "end of pattern" is a check against cd->end_pattern in the main loop,
+ instead of looking for a binary zero. This means that the special first-pass
+ call can adjust cd->end_pattern temporarily. (Checks for binary zero while
+ processing items within the loop are OK, because afterwards the main loop will
+ terminate.)
  Arguments:
    ptrptr       address of the current character pointer (updated)
-Line 1110 
 Arguments:
+Line 1132 
 Arguments:
    name         name to seek, or NULL if seeking a numbered subpattern
    lorn         name length, or subpattern number if name is NULL
    xmode        TRUE if we are in /x mode
+   utf8         TRUE if we are in UTF-8 mode
    count        pointer to the current capturing subpattern number (updated)
  Returns:       the number of the named subpattern, or -1 if not found
-Line 1117 
 Returns:       the number of the named s
+Line 1140 
 Returns:       the number of the named s
  static int
  find_parens_sub(uschar **ptrptr, compile_data *cd, const uschar *name, int lorn,
-   BOOL xmode, int *count)
+   BOOL xmode, BOOL utf8, int *count)
  {
  uschar *ptr = *ptrptr;
  int start_count = *count;
-Line 1130 
 dealing with. The very first call may no
+Line 1153 
 dealing with. The very first call may no
  if (ptr[0] == CHAR_LEFT_PARENTHESIS)
    {
    /* Handle specials such as (*SKIP) or (*UTF8) etc. */
    if (ptr[1] == CHAR_ASTERISK) ptr += 2;
    /* Handle a normal, unnamed capturing parenthesis. */
    else if (ptr[1] != CHAR_QUESTION_MARK)
-Line 1150 
 if (ptr[0] == CHAR_LEFT_PARENTHESIS)
+Line 1173 
 if (ptr[0] == CHAR_LEFT_PARENTHESIS)
      ptr += 3;
      dup_parens = TRUE;
      }
    /* Handle comments; all characters are allowed until a ket is reached. */
    else if (ptr[2] == CHAR_NUMBER_SIGN)
      {
      for (ptr += 3; *ptr != 0; ptr++) if (*ptr == CHAR_RIGHT_PARENTHESIS) break;
      goto FAIL_EXIT;
      }
    /* Handle a condition. If it is an assertion, just carry on so that it
    is processed as normal. If not, skip to the closing parenthesis of the
-Line 1202 
 if (ptr[0] == CHAR_LEFT_PARENTHESIS)
+Line 1225 
 if (ptr[0] == CHAR_LEFT_PARENTHESIS)
    }
  /* Past any initial parenthesis handling, scan for parentheses or vertical
- bars. */
+ bars. Stop if we get to cd->end_pattern. Note that this is important for the
+ first-pass call when this value is temporarily adjusted to stop at the current
+ position. So DO NOT change this to a test for binary zero. */
- for (; *ptr != 0; ptr++)
+ for (; ptr < cd->end_pattern; ptr++)
    {
    /* Skip over backslashed characters and also entire \Q...\E */
-Line 1278 
 for (; *ptr != 0; ptr++)
+Line 1303 
 for (; *ptr != 0; ptr++)
    if (xmode && *ptr == CHAR_NUMBER_SIGN)
      {
-     while (*(++ptr) != 0 && *ptr != CHAR_NL) {};
+     ptr++;
+     while (*ptr != 0)
+       {
+       if (IS_NEWLINE(ptr)) { ptr += cd->nllen - 1; break; }
+       ptr++;
+ #ifdef SUPPORT_UTF8
+       if (utf8) while ((*ptr & 0xc0) == 0x80) ptr++;
+ #endif
+       }
      if (*ptr == 0) goto FAIL_EXIT;
      continue;
      }
-Line 1287 
 for (; *ptr != 0; ptr++)
+Line 1320 
 for (; *ptr != 0; ptr++)
    if (*ptr == CHAR_LEFT_PARENTHESIS)
      {
-     int rc = find_parens_sub(&ptr, cd, name, lorn, xmode, count);
+     int rc = find_parens_sub(&ptr, cd, name, lorn, xmode, utf8, count);
      if (rc > 0) return rc;
      if (*ptr == 0) goto FAIL_EXIT;
      }
-Line 1295 
 for (; *ptr != 0; ptr++)
+Line 1328 
 for (; *ptr != 0; ptr++)
    else if (*ptr == CHAR_RIGHT_PARENTHESIS)
      {
      if (dup_parens && *count < hwm_count) *count = hwm_count;
      goto FAIL_EXIT;
      }
    else if (*ptr == CHAR_VERTICAL_LINE && dup_parens)
-Line 1333 
 Arguments:
+Line 1366 
 Arguments:
    name         name to seek, or NULL if seeking a numbered subpattern
    lorn         name length, or subpattern number if name is NULL
    xmode        TRUE if we are in /x mode
+   utf8         TRUE if we are in UTF-8 mode
  Returns:       the number of the found subpattern, or -1 if not found
  */
  static int
- find_parens(compile_data *cd, const uschar *name, int lorn, BOOL xmode)
+ find_parens(compile_data *cd, const uschar *name, int lorn, BOOL xmode,
+   BOOL utf8)
  {
  uschar *ptr = (uschar *)cd->start_pattern;
  int count = 0;
-Line 1351 
 matching closing parens. That is why we
+Line 1386 
 matching closing parens. That is why we
  for (;;)
    {
-   rc = find_parens_sub(&ptr, cd, name, lorn, xmode, &count);
+   rc = find_parens_sub(&ptr, cd, name, lorn, xmode, utf8, &count);
    if (rc > 0 || *ptr++ == 0) break;
    }
-Line 1367 
 return rc;
+Line 1402 
 return rc;
  /* 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 some calls, a change of option is important.
+ that do not influence this. For some calls, it makes sense to skip negative
- For some calls, it makes sense to skip negative forward and all backward
+ forward and all backward assertions, and also the \b assertion; for others it
- assertions, and also the \b assertion; for others it does not.
+ does not.
  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
    skipassert   TRUE if certain assertions are to be skipped
  Returns:       pointer to the first significant opcode
  */
  static const uschar*
- first_significant_code(const uschar *code, int *options, int optbit,
+ first_significant_code(const uschar *code, BOOL skipassert)
-   BOOL skipassert)
  {
  for (;;)
    {
    switch ((int)*code)
      {
-     case OP_OPT:
-     if (optbit > 0 && ((int)code[1] & optbit) != (*options & optbit))
-       *options = (int)code[1];
-     code += 2;
-     break;
      case OP_ASSERT_NOT:
      case OP_ASSERTBACK:
      case OP_ASSERTBACK_NOT:
-Line 1444 
 and doing the check at the end; a flag s
+Line 1469 
 and doing the check at the end; a flag s
  Arguments:
    code     points to the start of the pattern (the bracket)
-   options  the compiling options
+   utf8     TRUE in UTF-8 mode
    atend    TRUE if called when the pattern is complete
    cd       the "compile data" structure
-Line 1455 
 Returns:   the fixed length,
+Line 1480 
 Returns:   the fixed length,
  */
  static int
- find_fixedlength(uschar *code, int options, BOOL atend, compile_data *cd)
+ find_fixedlength(uschar *code, BOOL utf8, BOOL atend, compile_data *cd)
  {
  int length = -1;
-Line 1472 
 for (;;)
+Line 1497 
 for (;;)
    register int op = *cc;
    switch (op)
      {
+     /* We only need to continue for OP_CBRA (normal capturing bracket) and
+     OP_BRA (normal non-capturing bracket) because the other variants of these
+     opcodes are all concerned with unlimited repeated groups, which of course
+     are not of fixed length. They will cause a -1 response from the default
+     case of this switch. */
      case OP_CBRA:
      case OP_BRA:
      case OP_ONCE:
+     case OP_ONCE_NC:
      case OP_COND:
-     d = find_fixedlength(cc + ((op == OP_CBRA)? 2:0), options, atend, cd);
+     d = find_fixedlength(cc + ((op == OP_CBRA)? 2:0), utf8, atend, cd);
      if (d < 0) return d;
      branchlength += d;
      do cc += GET(cc, 1); while (*cc == OP_ALT);
-Line 1485 
 for (;;)
+Line 1517 
 for (;;)
      /* 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. */
+     END it's the end of the outer call. All can be handled by the same code.
+     Note that we must not include the OP_KETRxxx opcodes here, because they
+     all imply an unlimited repeat. */
      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;
-Line 1508 
 for (;;)
+Line 1540 
 for (;;)
      cs = ce = (uschar *)cd->start_code + GET(cc, 1);  /* Start subpattern */
      do ce += GET(ce, 1); while (*ce == OP_ALT);       /* End subpattern */
      if (cc > cs && cc < ce) return -1;                /* Recursion */
-     d = find_fixedlength(cs + 2, options, atend, cd);
+     d = find_fixedlength(cs + 2, utf8, atend, cd);
      if (d < 0) return d;
      branchlength += d;
      cc += 1 + LINK_SIZE;
-Line 1531 
 for (;;)
+Line 1563 
 for (;;)
      case OP_RREF:
      case OP_NRREF:
      case OP_DEF:
-     case OP_OPT:
      case OP_CALLOUT:
      case OP_SOD:
      case OP_SOM:
-Line 1539 
 for (;;)
+Line 1570 
 for (;;)
      case OP_EOD:
      case OP_EODN:
      case OP_CIRC:
+     case OP_CIRCM:
      case OP_DOLL:
+     case OP_DOLLM:
      case OP_NOT_WORD_BOUNDARY:
      case OP_WORD_BOUNDARY:
      cc += _pcre_OP_lengths[*cc];
-Line 1548 
 for (;;)
+Line 1581 
 for (;;)
      /* Handle literal characters */
      case OP_CHAR:
-     case OP_CHARNC:
+     case OP_CHARI:
      case OP_NOT:
+     case OP_NOTI:
      branchlength++;
      cc += 2;
  #ifdef SUPPORT_UTF8
-     if ((options & PCRE_UTF8) != 0 && cc[-1] >= 0xc0)
+     if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
-       cc += _pcre_utf8_table4[cc[-1] & 0x3f];
  #endif
      break;
-Line 1565 
 for (;;)
+Line 1598 
 for (;;)
      branchlength += GET2(cc,1);
      cc += 4;
  #ifdef SUPPORT_UTF8
-     if ((options & PCRE_UTF8) != 0 && cc[-1] >= 0xc0)
+     if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
-       cc += _pcre_utf8_table4[cc[-1] & 0x3f];
  #endif
      break;
-Line 1668 
 _pcre_find_bracket(const uschar *code, B
+Line 1700 
 _pcre_find_bracket(const uschar *code, B
  for (;;)
    {
    register int c = *code;
    if (c == OP_END) return NULL;
    /* XCLASS is used for classes that cannot be represented just by a bit
-Line 1686 
 for (;;)
+Line 1719 
 for (;;)
    /* Handle capturing bracket */
-   else if (c == OP_CBRA)
+   else if (c == OP_CBRA || c == OP_SCBRA ||
+            c == OP_CBRAPOS || c == OP_SCBRAPOS)
      {
      int n = GET2(code, 1+LINK_SIZE);
      if (n == number) return (uschar *)code;
-Line 1724 
 for (;;)
+Line 1758 
 for (;;)
        case OP_MARK:
        case OP_PRUNE_ARG:
        case OP_SKIP_ARG:
+       code += code[1];
+       break;
        case OP_THEN_ARG:
        code += code[1];
        break;
-Line 1741 
 for (;;)
+Line 1778 
 for (;;)
      if (utf8) switch(c)
        {
        case OP_CHAR:
-       case OP_CHARNC:
+       case OP_CHARI:
        case OP_EXACT:
+       case OP_EXACTI:
        case OP_UPTO:
+       case OP_UPTOI:
        case OP_MINUPTO:
+       case OP_MINUPTOI:
        case OP_POSUPTO:
+       case OP_POSUPTOI:
        case OP_STAR:
+       case OP_STARI:
        case OP_MINSTAR:
+       case OP_MINSTARI:
        case OP_POSSTAR:
+       case OP_POSSTARI:
        case OP_PLUS:
+       case OP_PLUSI:
        case OP_MINPLUS:
+       case OP_MINPLUSI:
        case OP_POSPLUS:
+       case OP_POSPLUSI:
        case OP_QUERY:
+       case OP_QUERYI:
        case OP_MINQUERY:
+       case OP_MINQUERYI:
        case OP_POSQUERY:
+       case OP_POSQUERYI:
        if (code[-1] >= 0xc0) code += _pcre_utf8_table4[code[-1] & 0x3f];
        break;
        }
-Line 1827 
 for (;;)
+Line 1877 
 for (;;)
        case OP_MARK:
        case OP_PRUNE_ARG:
        case OP_SKIP_ARG:
+       code += code[1];
+       break;
        case OP_THEN_ARG:
        code += code[1];
        break;
-Line 1844 
 for (;;)
+Line 1897 
 for (;;)
      if (utf8) switch(c)
        {
        case OP_CHAR:
-       case OP_CHARNC:
+       case OP_CHARI:
        case OP_EXACT:
+       case OP_EXACTI:
        case OP_UPTO:
+       case OP_UPTOI:
        case OP_MINUPTO:
+       case OP_MINUPTOI:
        case OP_POSUPTO:
+       case OP_POSUPTOI:
        case OP_STAR:
+       case OP_STARI:
        case OP_MINSTAR:
+       case OP_MINSTARI:
        case OP_POSSTAR:
+       case OP_POSSTARI:
        case OP_PLUS:
+       case OP_PLUSI:
        case OP_MINPLUS:
+       case OP_MINPLUSI:
        case OP_POSPLUS:
+       case OP_POSPLUSI:
        case OP_QUERY:
+       case OP_QUERYI:
        case OP_MINQUERY:
+       case OP_MINQUERYI:
        case OP_POSQUERY:
+       case OP_POSQUERYI:
        if (code[-1] >= 0xc0) code += _pcre_utf8_table4[code[-1] & 0x3f];
        break;
        }
-Line 1896 
 could_be_empty_branch(const uschar *code
+Line 1962 
 could_be_empty_branch(const uschar *code
    compile_data *cd)
  {
  register int c;
- for (code = first_significant_code(code + _pcre_OP_lengths[*code], NULL, 0, TRUE);
+ for (code = first_significant_code(code + _pcre_OP_lengths[*code], TRUE);
       code < endcode;
-      code = first_significant_code(code + _pcre_OP_lengths[c], NULL, 0, TRUE))
+      code = first_significant_code(code + _pcre_OP_lengths[c], TRUE))
    {
    const uschar *ccode;
-Line 1914 
 for (code = first_significant_code(code
+Line 1980 
 for (code = first_significant_code(code
      continue;
      }
-   /* Groups with zero repeats can of course be empty; skip them. */
-   if (c == OP_BRAZERO || c == OP_BRAMINZERO || c == OP_SKIPZERO)
-     {
-     code += _pcre_OP_lengths[c];
-     do code += GET(code, 1); while (*code == OP_ALT);
-     c = *code;
-     continue;
-     }
    /* For a recursion/subroutine call, if its end has been reached, which
-   implies a subroutine call, we can scan it. */
+   implies a backward reference subroutine call, we can scan it. If it's a
+   forward reference subroutine call, we can't. To detect forward reference
+   we have to scan up the list that is kept in the workspace. This function is
+   called only when doing the real compile, not during the pre-compile that
+   measures the size of the compiled pattern. */
    if (c == OP_RECURSE)
      {
-     BOOL empty_branch = FALSE;
+     const uschar *scode;
-     const uschar *scode = cd->start_code + GET(code, 1);
+     BOOL empty_branch;
+     /* Test for forward reference */
+     for (scode = cd->start_workspace; scode < cd->hwm; scode += LINK_SIZE)
+       if (GET(scode, 0) == code + 1 - cd->start_code) return TRUE;
+     /* Not a forward reference, test for completed backward reference */
+     empty_branch = FALSE;
+     scode = cd->start_code + GET(code, 1);
      if (GET(scode, 1) == 0) return TRUE;    /* Unclosed */
+     /* Completed backwards reference */
      do
        {
        if (could_be_empty_branch(scode, endcode, utf8, cd))
-Line 1942 
 for (code = first_significant_code(code
+Line 2015 
 for (code = first_significant_code(code
        scode += GET(scode, 1);
        }
      while (*scode == OP_ALT);
      if (!empty_branch) return FALSE;  /* All branches are non-empty */
      continue;
      }
+   /* Groups with zero repeats can of course be empty; skip them. */
+   if (c == OP_BRAZERO || c == OP_BRAMINZERO || c == OP_SKIPZERO ||
+       c == OP_BRAPOSZERO)
+     {
+     code += _pcre_OP_lengths[c];
+     do code += GET(code, 1); while (*code == OP_ALT);
+     c = *code;
+     continue;
+     }
+   /* A nested group that is already marked as "could be empty" can just be
+   skipped. */
+   if (c == OP_SBRA  || c == OP_SBRAPOS ||
+       c == OP_SCBRA || c == OP_SCBRAPOS)
+     {
+     do code += GET(code, 1); while (*code == OP_ALT);
+     c = *code;
+     continue;
+     }
    /* For other groups, scan the branches. */
-   if (c == OP_BRA || c == OP_CBRA || c == OP_ONCE || c == OP_COND)
+   if (c == OP_BRA  || c == OP_BRAPOS ||
+       c == OP_CBRA || c == OP_CBRAPOS ||
+       c == OP_ONCE || c == OP_ONCE_NC ||
+       c == OP_COND)
      {
      BOOL empty_branch;
      if (GET(code, 1) == 0) return TRUE;    /* Hit unclosed bracket */
-Line 2035 
 for (code = first_significant_code(code
+Line 2134 
 for (code = first_significant_code(code
      case OP_ALLANY:
      case OP_ANYBYTE:
      case OP_CHAR:
-     case OP_CHARNC:
+     case OP_CHARI:
      case OP_NOT:
+     case OP_NOTI:
      case OP_PLUS:
      case OP_MINPLUS:
      case OP_POSPLUS:
-Line 2076 
 for (code = first_significant_code(code
+Line 2176 
 for (code = first_significant_code(code
      case OP_KET:
      case OP_KETRMAX:
      case OP_KETRMIN:
+     case OP_KETRPOS:
      case OP_ALT:
      return TRUE;
-Line 2084 
 for (code = first_significant_code(code
+Line 2185 
 for (code = first_significant_code(code
  #ifdef SUPPORT_UTF8
      case OP_STAR:
+     case OP_STARI:
      case OP_MINSTAR:
+     case OP_MINSTARI:
      case OP_POSSTAR:
+     case OP_POSSTARI:
      case OP_QUERY:
+     case OP_QUERYI:
      case OP_MINQUERY:
+     case OP_MINQUERYI:
      case OP_POSQUERY:
+     case OP_POSQUERYI:
      if (utf8 && code[1] >= 0xc0) code += _pcre_utf8_table4[code[1] & 0x3f];
      break;
      case OP_UPTO:
+     case OP_UPTOI:
      case OP_MINUPTO:
+     case OP_MINUPTOI:
      case OP_POSUPTO:
+     case OP_POSUPTOI:
      if (utf8 && code[3] >= 0xc0) code += _pcre_utf8_table4[code[3] & 0x3f];
      break;
  #endif
-Line 2105 
 for (code = first_significant_code(code
+Line 2215 
 for (code = first_significant_code(code
      case OP_MARK:
      case OP_PRUNE_ARG:
      case OP_SKIP_ARG:
+     code += code[1];
+     break;
      case OP_THEN_ARG:
      code += code[1];
      break;
-Line 2129 
 return TRUE;
+Line 2242 
 return TRUE;
  the current branch of the current pattern to see if it could match the empty
  string. If it could, we must look outwards for branches at other levels,
  stopping when we pass beyond the bracket which is the subject of the recursion.
+ This function is called only during the real compile, not during the
+ pre-compile.
  Arguments:
    code        points to start of the recursion
-Line 2179 
 where Perl recognizes it as the POSIX cl
+Line 2294 
 where Perl recognizes it as the POSIX cl
  "l\ower". This is a lesser evil that not diagnosing bad classes when Perl does,
  I think.
+ A user pointed out that PCRE was rejecting [:a[:digit:]] whereas Perl was not.
+ It seems that the appearance of a nested POSIX class supersedes an apparent
+ external class. For example, [:a[:digit:]b:] matches "a", "b", ":", or
+ a digit.
+ In Perl, unescaped square brackets may also appear as part of class names. For
+ example, [:a[:abc]b:] gives unknown POSIX class "[:abc]b:]". However, for
+ [:a[:abc]b][b:] it gives unknown POSIX class "[:abc]b][b:]", which does not
+ seem right at all. PCRE does not allow closing square brackets in POSIX class
+ names.
  Arguments:
    ptr      pointer to the initial [
    endptr   where to return the end pointer
-Line 2193 
 int terminator;          /* Don't combin
+Line 2319 
 int terminator;          /* Don't combin
  terminator = *(++ptr);   /* compiler warns about "non-constant" initializer. */
  for (++ptr; *ptr != 0; ptr++)
    {
-   if (*ptr == CHAR_BACKSLASH && ptr[1] == CHAR_RIGHT_SQUARE_BRACKET) ptr++; else
+   if (*ptr == CHAR_BACKSLASH && ptr[1] == CHAR_RIGHT_SQUARE_BRACKET)
+     ptr++;
+   else if (*ptr == CHAR_RIGHT_SQUARE_BRACKET) return FALSE;
+   else
      {
-     if (*ptr == CHAR_RIGHT_SQUARE_BRACKET) return FALSE;
      if (*ptr == terminator && ptr[1] == CHAR_RIGHT_SQUARE_BRACKET)
        {
        *endptr = ptr;
        return TRUE;
        }
+     if (*ptr == CHAR_LEFT_SQUARE_BRACKET &&
+          (ptr[1] == CHAR_COLON || ptr[1] == CHAR_DOT ||
+           ptr[1] == CHAR_EQUALS_SIGN) &&
+         check_posix_syntax(ptr, endptr))
+       return FALSE;
      }
    }
  return FALSE;
-Line 2506 
 if ((options & PCRE_EXTENDED) != 0)
+Line 2639 
 if ((options & PCRE_EXTENDED) != 0)
      while ((cd->ctypes[*ptr] & ctype_space) != 0) ptr++;
      if (*ptr == CHAR_NUMBER_SIGN)
        {
-       while (*(++ptr) != 0)
+       ptr++;
+       while (*ptr != 0)
+         {
          if (IS_NEWLINE(ptr)) { ptr += cd->nllen; break; }
+         ptr++;
+ #ifdef SUPPORT_UTF8
+         if (utf8) while ((*ptr & 0xc0) == 0x80) ptr++;
+ #endif
+         }
        }
      else break;
      }
-Line 2543 
 if ((options & PCRE_EXTENDED) != 0)
+Line 2683 
 if ((options & PCRE_EXTENDED) != 0)
      while ((cd->ctypes[*ptr] & ctype_space) != 0) ptr++;
      if (*ptr == CHAR_NUMBER_SIGN)
        {
-       while (*(++ptr) != 0)
+       ptr++;
+       while (*ptr != 0)
+         {
          if (IS_NEWLINE(ptr)) { ptr += cd->nllen; break; }
+         ptr++;
+ #ifdef SUPPORT_UTF8
+         if (utf8) while ((*ptr & 0xc0) == 0x80) ptr++;
+ #endif
+         }
        }
      else break;
      }
-Line 2569 
 if (next >= 0) switch(op_code)
+Line 2716 
 if (next >= 0) switch(op_code)
  #endif
    return c != next;
-   /* For CHARNC (caseless character) we must check the other case. If we have
+   /* For CHARI (caseless character) we must check the other case. If we have
    Unicode property support, we can use it to test the other case of
    high-valued characters. */
-   case OP_CHARNC:
+   case OP_CHARI:
  #ifdef SUPPORT_UTF8
    GETCHARTEST(c, previous);
  #else
-Line 2596 
 if (next >= 0) switch(op_code)
+Line 2743 
 if (next >= 0) switch(op_code)
  #endif  /* SUPPORT_UTF8 */
    return (c != cd->fcc[next]);  /* Non-UTF-8 mode */
-   /* For OP_NOT, its data is always a single-byte character. */
+   /* For OP_NOT and OP_NOTI, the data is always a single-byte character. These
+   opcodes are not used for multi-byte characters, because they are coded using
+   an XCLASS instead. */
    case OP_NOT:
+   return (c = *previous) == next;
+   case OP_NOTI:
    if ((c = *previous) == next) return TRUE;
-   if ((options & PCRE_CASELESS) == 0) return FALSE;
  #ifdef SUPPORT_UTF8
    if (utf8)
      {
-Line 2705 
 replaced by OP_PROP codes when PCRE_UCP
+Line 2856 
 replaced by OP_PROP codes when PCRE_UCP
  switch(op_code)
    {
    case OP_CHAR:
-   case OP_CHARNC:
+   case OP_CHARI:
  #ifdef SUPPORT_UTF8
    GETCHARTEST(c, previous);
  #else
-Line 2892 
 Arguments:
+Line 3043 
 Arguments:
    firstbyteptr   set to initial literal character, or < 0 (REQ_UNSET, REQ_NONE)
    reqbyteptr     set to the last literal character required, else < 0
    bcptr          points to current branch chain
+   cond_depth     conditional nesting depth
    cd             contains pointers to tables etc.
    lengthptr      NULL during the real compile phase
                   points to length accumulator during pre-compile phase
-Line 2903 
 Returns:         TRUE on success
+Line 3055 
 Returns:         TRUE on success
  static BOOL
  compile_branch(int *optionsptr, uschar **codeptr, const uschar **ptrptr,
    int *errorcodeptr, int *firstbyteptr, int *reqbyteptr, branch_chain *bcptr,
-   compile_data *cd, int *lengthptr)
+   int cond_depth, compile_data *cd, int *lengthptr)
  {
  int repeat_type, op_type;
  int repeat_min = 0, repeat_max = 0;      /* To please picky compilers */
-Line 2912 
 int greedy_default, greedy_non_default;
+Line 3064 
 int greedy_default, greedy_non_default;
  int firstbyte, reqbyte;
  int zeroreqbyte, zerofirstbyte;
  int req_caseopt, reqvary, tempreqvary;
- int options = *optionsptr;
+ int options = *optionsptr;               /* May change dynamically */
  int after_manual_callout = 0;
  int length_prevgroup = 0;
  register int c;
-Line 2930 
 uschar *previous_callout = NULL;
+Line 3082 
 uschar *previous_callout = NULL;
  uschar *save_hwm = NULL;
  uschar classbits[32];
+ /* We can fish out the UTF-8 setting once and for all into a BOOL, but we
+ must not do this for other options (e.g. PCRE_EXTENDED) because they may change
+ dynamically as we process the pattern. */
  #ifdef SUPPORT_UTF8
  BOOL class_utf8;
  BOOL utf8 = (options & PCRE_UTF8) != 0;
-Line 2938 
 uschar *class_utf8data_base;
+Line 3094 
 uschar *class_utf8data_base;
  uschar utf8_char[6];
  #else
  BOOL utf8 = FALSE;
- uschar *utf8_char = NULL;
  #endif
  #ifdef PCRE_DEBUG
-Line 2989 
 for (;; ptr++)
+Line 3144 
 for (;; ptr++)
    int subfirstbyte;
    int terminator;
    int mclength;
+   int tempbracount;
    uschar mcbuffer[8];
    /* Get next byte in the pattern */
-Line 3110 
 for (;; ptr++)
+Line 3266 
 for (;; ptr++)
      previous_callout = NULL;
      }
-   /* In extended mode, skip white space and comments */
+   /* In extended mode, skip white space and comments. */
    if ((options & PCRE_EXTENDED) != 0)
      {
      if ((cd->ctypes[c] & ctype_space) != 0) continue;
      if (c == CHAR_NUMBER_SIGN)
        {
-       while (*(++ptr) != 0)
+       ptr++;
+       while (*ptr != 0)
          {
          if (IS_NEWLINE(ptr)) { ptr += cd->nllen - 1; break; }
+         ptr++;
+ #ifdef SUPPORT_UTF8
+         if (utf8) while ((*ptr & 0xc0) == 0x80) ptr++;
+ #endif
          }
        if (*ptr != 0) continue;
-Line 3164 
 for (;; ptr++)
+Line 3325 
 for (;; ptr++)
      the setting of any following char as a first character. */
      case CHAR_CIRCUMFLEX_ACCENT:
+     previous = NULL;
      if ((options & PCRE_MULTILINE) != 0)
        {
        if (firstbyte == REQ_UNSET) firstbyte = REQ_NONE;
+       *code++ = OP_CIRCM;
        }
-     previous = NULL;
+     else *code++ = OP_CIRC;
-     *code++ = OP_CIRC;
      break;
      case CHAR_DOLLAR_SIGN:
      previous = NULL;
-     *code++ = OP_DOLL;
+     *code++ = ((options & PCRE_MULTILINE) != 0)? OP_DOLLM : OP_DOLL;
      break;
      /* There can never be a first char if '.' is first, whatever happens about
-Line 3494 
 for (;; ptr++)
+Line 3656 
 for (;; ptr++)
              for (c = 0; c < 32; c++) classbits[c] |= ~cbits[c+cbit_word];
              continue;
+             /* Perl 5.004 onwards omits VT from \s, but we must preserve it
+             if it was previously set by something earlier in the character
+             class. */
              case ESC_s:
-             for (c = 0; c < 32; c++) classbits[c] |= cbits[c+cbit_space];
+             classbits[0] |= cbits[cbit_space];
-             classbits[1] &= ~0x08;   /* Perl 5.004 onwards omits VT from \s */
+             classbits[1] |= cbits[cbit_space+1] & ~0x08;
+             for (c = 2; c < 32; c++) classbits[c] |= cbits[c+cbit_space];
              continue;
              case ESC_S:
-Line 3915 
 for (;; ptr++)
+Line 4082 
 for (;; ptr++)
      In UTF-8 mode, we can optimize the negative case only if there were no
      characters >= 128 because OP_NOT and the related opcodes like OP_NOTSTAR
-     operate on single-bytes only. This is an historical hangover. Maybe one day
+     operate on single-bytes characters only. This is an historical hangover.
-     we can tidy these opcodes to handle multi-byte characters.
+     Maybe one day we can tidy these opcodes to handle multi-byte characters.
      The optimization throws away the bit map. We turn the item into a
--character OP_CHAR[NC] if it's positive, or OP_NOT if it's negative. Note
+-character OP_CHAR[I] if it's positive, or OP_NOT[I] if it's negative.
-     that OP_NOT does not support multibyte characters. In the positive case, it
+     Note that OP_NOT[I] does not support multibyte characters. In the positive
-     can cause firstbyte to be set. Otherwise, there can be no first char if
+     case, it can cause firstbyte to be set. Otherwise, there can be no first
-     this item is first, whatever repeat count may follow. In the case of
+     char if this item is first, whatever repeat count may follow. In the case
-     reqbyte, save the previous value for reinstating. */
+     of reqbyte, save the previous value for reinstating. */
  #ifdef SUPPORT_UTF8
      if (class_charcount == 1 && !class_utf8 &&
-Line 3934 
 for (;; ptr++)
+Line 4101 
 for (;; ptr++)
        {
        zeroreqbyte = reqbyte;
-       /* The OP_NOT opcode works on one-byte characters only. */
+       /* The OP_NOT[I] opcodes work on one-byte characters only. */
        if (negate_class)
          {
          if (firstbyte == REQ_UNSET) firstbyte = REQ_NONE;
          zerofirstbyte = firstbyte;
-         *code++ = OP_NOT;
+         *code++ = ((options & PCRE_CASELESS) != 0)? OP_NOTI: OP_NOT;
          *code++ = class_lastchar;
          break;
          }
-Line 4068 
 for (;; ptr++)
+Line 4235 
 for (;; ptr++)
      op_type = 0;                    /* Default single-char op codes */
      possessive_quantifier = FALSE;  /* Default not possessive quantifier */
-     /* Save start of previous item, in case we have to move it up to make space
+     /* Save start of previous item, in case we have to move it up in order to
-     for an inserted OP_ONCE for the additional '+' extension. */
+     insert something before it. */
      tempcode = previous;
-Line 4092 
 for (;; ptr++)
+Line 4259 
 for (;; ptr++)
        }
      else repeat_type = greedy_default;
+     /* If previous was a recursion call, wrap it in atomic brackets so that
+     previous becomes the atomic group. All recursions were so wrapped in the
+     past, but it no longer happens for non-repeated recursions. In fact, the
+     repeated ones could be re-implemented independently so as not to need this,
+     but for the moment we rely on the code for repeating groups. */
+     if (*previous == OP_RECURSE)
+       {
+       memmove(previous + 1 + LINK_SIZE, previous, 1 + LINK_SIZE);
+       *previous = OP_ONCE;
+       PUT(previous, 1, 2 + 2*LINK_SIZE);
+       previous[2 + 2*LINK_SIZE] = OP_KET;
+       PUT(previous, 3 + 2*LINK_SIZE, 2 + 2*LINK_SIZE);
+       code += 2 + 2 * LINK_SIZE;
+       length_prevgroup = 3 + 3*LINK_SIZE;
+       /* When actually compiling, we need to check whether this was a forward
+       reference, and if so, adjust the offset. */
+       if (lengthptr == NULL && cd->hwm >= cd->start_workspace + LINK_SIZE)
+         {
+         int offset = GET(cd->hwm, -LINK_SIZE);
+         if (offset == previous + 1 - cd->start_code)
+           PUT(cd->hwm, -LINK_SIZE, offset + 1 + LINK_SIZE);
+         }
+       }
+     /* Now handle repetition for the different types of item. */
      /* If previous was a character match, abolish the item and generate a
      repeat item instead. If a char item has a minumum of more than one, ensure
      that it is set in reqbyte - it might not be if a sequence such as x{3} is
      the first thing in a branch because the x will have gone into firstbyte
      instead.  */
-     if (*previous == OP_CHAR || *previous == OP_CHARNC)
+     if (*previous == OP_CHAR || *previous == OP_CHARI)
        {
+       op_type = (*previous == OP_CHAR)? 0 : OP_STARI - OP_STAR;
        /* Deal with UTF-8 characters that take up more than one byte. It's
        easier to write this out separately than try to macrify it. Use c to
        hold the length of the character in bytes, plus 0x80 to flag that it's a
-Line 4144 
 for (;; ptr++)
+Line 4342 
 for (;; ptr++)
      /* If previous was a single negated character ([^a] or similar), we use
      one of the special opcodes, replacing it. The code is shared with single-
      character repeats by setting opt_type to add a suitable offset into
-     repeat_type. We can also test for auto-possessification. OP_NOT is
+     repeat_type. We can also test for auto-possessification. OP_NOT and OP_NOTI
-     currently used only for single-byte chars. */
+     are currently used only for single-byte chars. */
-     else if (*previous == OP_NOT)
+     else if (*previous == OP_NOT || *previous == OP_NOTI)
        {
-       op_type = OP_NOTSTAR - OP_STAR;  /* Use "not" opcodes */
+       op_type = ((*previous == OP_NOT)? OP_NOTSTAR : OP_NOTSTARI) - OP_STAR;
        c = previous[1];
        if (!possessive_quantifier &&
            repeat_max < 0 &&
-Line 4346 
 for (;; ptr++)
+Line 4544 
 for (;; ptr++)
  #ifdef SUPPORT_UTF8
               *previous == OP_XCLASS ||
  #endif
-              *previous == OP_REF)
+              *previous == OP_REF ||
+              *previous == OP_REFI)
        {
        if (repeat_max == 0)
          {
-Line 4380 
 for (;; ptr++)
+Line 4579 
 for (;; ptr++)
        }
      /* If previous was a bracket group, we may have to replicate it in certain
-     cases. */
+     cases. Note that at this point we can encounter only the "basic" bracket
+     opcodes such as BRA and CBRA, as this is the place where they get converted
+     into the more special varieties such as BRAPOS and SBRA. A test for >=
+     OP_ASSERT and <= OP_COND includes ASSERT, ASSERT_NOT, ASSERTBACK,
+     ASSERTBACK_NOT, ONCE, BRA, CBRA, and COND. Originally, PCRE did not allow
+     repetition of assertions, but now it does, for Perl compatibility. */
-     else if (*previous == OP_BRA  || *previous == OP_CBRA ||
+     else if (*previous >= OP_ASSERT && *previous <= OP_COND)
-              *previous == OP_ONCE || *previous == OP_COND)
        {
        register int i;
-       int ketoffset = 0;
        int len = (int)(code - previous);
        uschar *bralink = NULL;
+       uschar *brazeroptr = NULL;
-       /* Repeating a DEFINE group is pointless */
+       /* Repeating a DEFINE group is pointless, but Perl allows the syntax, so
+       we just ignore the repeat. */
        if (*previous == OP_COND && previous[LINK_SIZE+1] == OP_DEF)
-         {
+         goto END_REPEAT;
-         *errorcodeptr = ERR55;
-         goto FAILED;
+       /* There is no sense in actually repeating assertions. The only potential
-         }
+       use of repetition is in cases when the assertion is optional. Therefore,
+       if the minimum is greater than zero, just ignore the repeat. If the
+       maximum is not not zero or one, set it to 1. */
-       /* If the maximum repeat count is unlimited, find the end of the bracket
+       if (*previous < OP_ONCE)    /* Assertion */
-       by scanning through from the start, and compute the offset back to it
+         {
-       from the current code pointer. There may be an OP_OPT setting following
+         if (repeat_min > 0) goto END_REPEAT;
-       the final KET, so we can't find the end just by going back from the code
+         if (repeat_max < 0 || repeat_max > 1) repeat_max = 1;
-       pointer. */
-       if (repeat_max == -1)
-         {
-         register uschar *ket = previous;
-         do ket += GET(ket, 1); while (*ket != OP_KET);
-         ketoffset = (int)(code - ket);
          }
        /* The case of a zero minimum is special because of the need to stick
-Line 4429 
 for (;; ptr++)
+Line 4628 
 for (;; ptr++)
          **   goto END_REPEAT;
          **   }
-         However, that fails when a group is referenced as a subroutine from
+         However, that fails when a group or a subgroup within it is referenced
-         elsewhere in the pattern, so now we stick in OP_SKIPZERO in front of it
+         as a subroutine from elsewhere in the pattern, so now we stick in
-         so that it is skipped on execution. As we don't have a list of which
+         OP_SKIPZERO in front of it so that it is skipped on execution. As we
-         groups are referenced, we cannot do this selectively.
+         don't have a list of which groups are referenced, we cannot do this
+         selectively.
          If the maximum is 1 or unlimited, we just have to stick in the BRAZERO
          and do no more at this point. However, we do need to adjust any
-Line 4452 
 for (;; ptr++)
+Line 4652 
 for (;; ptr++)
              *previous++ = OP_SKIPZERO;
              goto END_REPEAT;
              }
+           brazeroptr = previous;    /* Save for possessive optimizing */
            *previous++ = OP_BRAZERO + repeat_type;
            }
-Line 4616 
 for (;; ptr++)
+Line 4817 
 for (;; ptr++)
            }
          }
-       /* If the maximum is unlimited, set a repeater in the final copy. We
+       /* If the maximum is unlimited, set a repeater in the final copy. For
-       can't just offset backwards from the current code point, because we
+       ONCE brackets, that's all we need to do. However, possessively repeated
-       don't know if there's been an options resetting after the ket. The
+       ONCE brackets can be converted into non-capturing brackets, as the
-       correct offset was computed above.
+       behaviour of (?:xx)++ is the same as (?>xx)++ and this saves having to
+       deal with possessive ONCEs specially.
+       Otherwise, if the quantifier was possessive, we convert the BRA code to
+       the POS form, and the KET code to KETRPOS. (It turns out to be convenient
+       at runtime to detect this kind of subpattern at both the start and at the
+       end.) The use of special opcodes makes it possible to reduce greatly the
+       stack usage in pcre_exec(). If the group is preceded by OP_BRAZERO,
+       convert this to OP_BRAPOSZERO. Then cancel the possessive flag so that
+       the default action below, of wrapping everything inside atomic brackets,
+       does not happen.
        Then, when we are doing the actual compile phase, check to see whether
-       this group is a non-atomic one that could match an empty string. If so,
+       this group is one that could match an empty string. If so, convert the
-       convert the initial operator to the S form (e.g. OP_BRA -> OP_SBRA) so
+       initial operator to the S form (e.g. OP_BRA -> OP_SBRA) so that runtime
-       that runtime checking can be done. [This check is also applied to
+       checking can be done. [This check is also applied to ONCE groups at
-       atomic groups at runtime, but in a different way.] */
+       runtime, but in a different way.] */
        else
          {
-         uschar *ketcode = code - ketoffset;
+         uschar *ketcode = code - 1 - LINK_SIZE;
          uschar *bracode = ketcode - GET(ketcode, 1);
-         *ketcode = OP_KETRMAX + repeat_type;
-         if (lengthptr == NULL && *bracode != OP_ONCE)
+         if ((*bracode == OP_ONCE || *bracode == OP_ONCE_NC) &&
+             possessive_quantifier) *bracode = OP_BRA;
+         if (*bracode == OP_ONCE || *bracode == OP_ONCE_NC)
+           *ketcode = OP_KETRMAX + repeat_type;
+         else
            {
-           uschar *scode = bracode;
+           if (possessive_quantifier)
-           do
+             {
+             *bracode += 1;                   /* Switch to xxxPOS opcodes */
+             *ketcode = OP_KETRPOS;
+             if (brazeroptr != NULL) *brazeroptr = OP_BRAPOSZERO;
+             possessive_quantifier = FALSE;
+             }
+           else *ketcode = OP_KETRMAX + repeat_type;
+           if (lengthptr == NULL)
              {
-             if (could_be_empty_branch(scode, ketcode, utf8, cd))
+             uschar *scode = bracode;
+             do
                {
-               *bracode += OP_SBRA - OP_BRA;
+               if (could_be_empty_branch(scode, ketcode, utf8, cd))
-               break;
+                 {
+                 *bracode += OP_SBRA - OP_BRA;
+                 break;
+                 }
+               scode += GET(scode, 1);
                }
-             scode += GET(scode, 1);
+             while (*scode == OP_ALT);
              }
-           while (*scode == OP_ALT);
            }
          }
        }
-Line 4665 
 for (;; ptr++)
+Line 4893 
 for (;; ptr++)
        }
      /* If the character following a repeat is '+', or if certain optimization
-     tests above succeeded, possessive_quantifier is TRUE. For some of the
+     tests above succeeded, possessive_quantifier is TRUE. For some opcodes,
-     simpler opcodes, there is an special alternative opcode for this. For
+     there are special alternative opcodes for this case. For anything else, we
-     anything else, we wrap the entire repeated item inside OP_ONCE brackets.
+     wrap the entire repeated item inside OP_ONCE brackets. Logically, the '+'
-     The '+' notation is just syntactic sugar, taken from Sun's Java package,
+     notation is just syntactic sugar, taken from Sun's Java package, but the
-     but the special opcodes can optimize it a bit. The repeated item starts at
+     special opcodes can optimize it.
-     tempcode, not at previous, which might be the first part of a string whose
-     (former) last char we repeated.
+     Possessively repeated subpatterns have already been handled in the code
+     just above, so possessive_quantifier is always FALSE for them at this
+     stage.
+     Note that the repeated item starts at tempcode, not at previous, which
+     might be the first part of a string whose (former) last char we repeated.
      Possessifying an 'exact' quantifier has no effect, so we can ignore it. But
      an 'upto' may follow. We skip over an 'exact' item, and then test the
-Line 4702 
 for (;; ptr++)
+Line 4935 
 for (;; ptr++)
          case OP_QUERY: *tempcode = OP_POSQUERY; break;
          case OP_UPTO:  *tempcode = OP_POSUPTO; break;
-         case OP_TYPESTAR:  *tempcode = OP_TYPEPOSSTAR; break;
+         case OP_STARI:  *tempcode = OP_POSSTARI; break;
-         case OP_TYPEPLUS:  *tempcode = OP_TYPEPOSPLUS; break;
+         case OP_PLUSI:  *tempcode = OP_POSPLUSI; break;
-         case OP_TYPEQUERY: *tempcode = OP_TYPEPOSQUERY; break;
+         case OP_QUERYI: *tempcode = OP_POSQUERYI; break;
-         case OP_TYPEUPTO:  *tempcode = OP_TYPEPOSUPTO; break;
+         case OP_UPTOI:  *tempcode = OP_POSUPTOI; break;
          case OP_NOTSTAR:  *tempcode = OP_NOTPOSSTAR; break;
          case OP_NOTPLUS:  *tempcode = OP_NOTPOSPLUS; break;
          case OP_NOTQUERY: *tempcode = OP_NOTPOSQUERY; break;
          case OP_NOTUPTO:  *tempcode = OP_NOTPOSUPTO; break;
+         case OP_NOTSTARI:  *tempcode = OP_NOTPOSSTARI; break;
+         case OP_NOTPLUSI:  *tempcode = OP_NOTPOSPLUSI; break;
+         case OP_NOTQUERYI: *tempcode = OP_NOTPOSQUERYI; break;
+         case OP_NOTUPTOI:  *tempcode = OP_NOTPOSUPTOI; break;
+         case OP_TYPESTAR:  *tempcode = OP_TYPEPOSSTAR; break;
+         case OP_TYPEPLUS:  *tempcode = OP_TYPEPOSPLUS; break;
+         case OP_TYPEQUERY: *tempcode = OP_TYPEPOSQUERY; break;
+         case OP_TYPEUPTO:  *tempcode = OP_TYPEPOSUPTO; break;
          /* Because we are moving code along, we must ensure that any
          pending recursive references are updated. */
-Line 4765 
 for (;; ptr++)
+Line 5008 
 for (;; ptr++)
        while ((cd->ctypes[*++ptr] & ctype_letter) != 0) {};
        namelen = (int)(ptr - name);
+       /* It appears that Perl allows any characters whatsoever, other than
+       a closing parenthesis, to appear in arguments, so we no longer insist on
+       letters, digits, and underscores. */
        if (*ptr == CHAR_COLON)
          {
          arg = ++ptr;
-         while ((cd->ctypes[*ptr] & (ctype_letter|ctype_digit)) != 0
+         while (*ptr != 0 && *ptr != CHAR_RIGHT_PARENTHESIS) ptr++;
-           || *ptr == '_') ptr++;
          arglen = (int)(ptr - arg);
          }
-Line 4786 
 for (;; ptr++)
+Line 5032 
 for (;; ptr++)
          if (namelen == verbs[i].len &&
              strncmp((char *)name, vn, namelen) == 0)
            {
-           /* Check for open captures before ACCEPT */
+           /* Check for open captures before ACCEPT and convert it to
+           ASSERT_ACCEPT if in an assertion. */
            if (verbs[i].op == OP_ACCEPT)
              {
              open_capitem *oc;
+             if (arglen != 0)
+               {
+               *errorcodeptr = ERR59;
+               goto FAILED;
+               }
              cd->had_accept = TRUE;
              for (oc = cd->open_caps; oc != NULL; oc = oc->next)
                {
                *code++ = OP_CLOSE;
                PUT2INC(code, 0, oc->number);
                }
+             *code++ = (cd->assert_depth > 0)? OP_ASSERT_ACCEPT : OP_ACCEPT;
+             /* Do not set firstbyte after *ACCEPT */
+             if (firstbyte == REQ_UNSET) firstbyte = REQ_NONE;
              }
-           /* Handle the cases with/without an argument */
+           /* Handle other cases with/without an argument */
-           if (arglen == 0)
+           else if (arglen == 0)
              {
              if (verbs[i].op < 0)   /* Argument is mandatory */
                {
                *errorcodeptr = ERR66;
                goto FAILED;
                }
-             *code++ = verbs[i].op;
+             *code = verbs[i].op;
+             if (*code++ == OP_THEN) cd->external_flags |= PCRE_HASTHEN;
              }
            else
-Line 4818 
 for (;; ptr++)
+Line 5075 
 for (;; ptr++)
                *errorcodeptr = ERR59;
                goto FAILED;
                }
-             *code++ = verbs[i].op_arg;
+             *code = verbs[i].op_arg;
+             if (*code++ == OP_THEN_ARG) cd->external_flags |= PCRE_HASTHEN;
              *code++ = arglen;
              memcpy(code, arg, arglen);
              code += arglen;
-Line 5012 
 for (;; ptr++)
+Line 5270 
 for (;; ptr++)
          /* Search the pattern for a forward reference */
          else if ((i = find_parens(cd, name, namelen,
-                         (options & PCRE_EXTENDED) != 0)) > 0)
+                         (options & PCRE_EXTENDED) != 0, utf8)) > 0)
            {
            PUT2(code, 2+LINK_SIZE, i);
            code[1+LINK_SIZE]++;
-Line 5080 
 for (;; ptr++)
+Line 5338 
 for (;; ptr++)
          /* ------------------------------------------------------------ */
          case CHAR_EQUALS_SIGN:                 /* Positive lookahead */
          bravalue = OP_ASSERT;
+         cd->assert_depth += 1;
          ptr++;
          break;
-Line 5094 
 for (;; ptr++)
+Line 5353 
 for (;; ptr++)
            continue;
            }
          bravalue = OP_ASSERT_NOT;
+         cd->assert_depth += 1;
          break;
-Line 5103 
 for (;; ptr++)
+Line 5363 
 for (;; ptr++)
            {
            case CHAR_EQUALS_SIGN:               /* Positive lookbehind */
            bravalue = OP_ASSERTBACK;
+           cd->assert_depth += 1;
            ptr += 2;
            break;
            case CHAR_EXCLAMATION_MARK:          /* Negative lookbehind */
            bravalue = OP_ASSERTBACK_NOT;
+           cd->assert_depth += 1;
            ptr += 2;
            break;
-Line 5313 
 for (;; ptr++)
+Line 5575 
 for (;; ptr++)
          while ((cd->ctypes[*ptr] & ctype_word) != 0) ptr++;
          namelen = (int)(ptr - name);
-         /* In the pre-compile phase, do a syntax check and set a dummy
+         /* In the pre-compile phase, do a syntax check. We used to just set
-         reference number. */
+         a dummy reference number, because it was not used in the first pass.
+         However, with the change of recursive back references to be atomic,
+         we have to look for the number so that this state can be identified, as
+         otherwise the incorrect length is computed. If it's not a backwards
+         reference, the dummy number will do. */
          if (lengthptr != NULL)
            {
+           const uschar *temp;
            if (namelen == 0)
              {
              *errorcodeptr = ERR62;
-Line 5333 
 for (;; ptr++)
+Line 5601 
 for (;; ptr++)
              *errorcodeptr = ERR48;
              goto FAILED;
              }
-           recno = 0;
+           /* The name table does not exist in the first pass, so we cannot
+           do a simple search as in the code below. Instead, we have to scan the
+           pattern to find the number. It is important that we scan it only as
+           far as we have got because the syntax of named subpatterns has not
+           been checked for the rest of the pattern, and find_parens() assumes
+           correct syntax. In any case, it's a waste of resources to scan
+           further. We stop the scan at the current point by temporarily
+           adjusting the value of cd->endpattern. */
+           temp = cd->end_pattern;
+           cd->end_pattern = ptr;
+           recno = find_parens(cd, name, namelen,
+             (options & PCRE_EXTENDED) != 0, utf8);
+           cd->end_pattern = temp;
+           if (recno < 0) recno = 0;    /* Forward ref; set dummy number */
            }
          /* In the real compile, seek the name in the table. We check the name
-Line 5358 
 for (;; ptr++)
+Line 5641 
 for (;; ptr++)
              }
            else if ((recno =                /* Forward back reference */
                      find_parens(cd, name, namelen,
-                       (options & PCRE_EXTENDED) != 0)) <= 0)
+                       (options & PCRE_EXTENDED) != 0, utf8)) <= 0)
              {
              *errorcodeptr = ERR15;
              goto FAILED;
-Line 5469 
 for (;; ptr++)
+Line 5752 
 for (;; ptr++)
              if (called == NULL)
                {
                if (find_parens(cd, NULL, recno,
-                     (options & PCRE_EXTENDED) != 0) < 0)
+                     (options & PCRE_EXTENDED) != 0, utf8) < 0)
                  {
                  *errorcodeptr = ERR15;
                  goto FAILED;
-Line 5477 
 for (;; ptr++)
+Line 5760 
 for (;; ptr++)
                /* Fudge the value of "called" so that when it is inserted as an
                offset below, what it actually inserted is the reference number
-               of the group. */
+               of the group. Then remember the forward reference. */
                called = cd->start_code + recno;
-               PUTINC(cd->hwm, 0, (int)(code + 2 + LINK_SIZE - cd->start_code));
+               PUTINC(cd->hwm, 0, (int)(code + 1 - cd->start_code));
                }
              /* If not a forward reference, and the subpattern is still open,
              this is a recursive call. We check to see if this is a left
-             recursion that could loop for ever, and diagnose that case. */
+             recursion that could loop for ever, and diagnose that case. We
+             must not, however, do this check if we are in a conditional
+             subpattern because the condition might be testing for recursion in
+             a pattern such as /(?(R)a+|(?R)b)/, which is perfectly valid.
+             Forever loops are also detected at runtime, so those that occur in
+             conditional subpatterns will be picked up then. */
-             else if (GET(called, 1) == 0 &&
+             else if (GET(called, 1) == 0 && cond_depth <= 0 &&
                       could_be_empty(called, code, bcptr, utf8, cd))
                {
                *errorcodeptr = ERR40;
-Line 5495 
 for (;; ptr++)
+Line 5783 
 for (;; ptr++)
                }
              }
-           /* Insert the recursion/subroutine item, automatically wrapped inside
+           /* Insert the recursion/subroutine item. */
-           "once" brackets. Set up a "previous group" length so that a
-           subsequent quantifier will work. */
-           *code = OP_ONCE;
-           PUT(code, 1, 2 + 2*LINK_SIZE);
-           code += 1 + LINK_SIZE;
            *code = OP_RECURSE;
            PUT(code, 1, (int)(called - cd->start_code));
            code += 1 + LINK_SIZE;
-           *code = OP_KET;
-           PUT(code, 1, 2 + 2*LINK_SIZE);
-           code += 1 + LINK_SIZE;
-           length_prevgroup = 3 + 3*LINK_SIZE;
            }
          /* Can't determine a first byte now */
-Line 5572 
 for (;; ptr++)
+Line 5848 
 for (;; ptr++)
          is necessary to ensure we correctly detect the start of the pattern in
          both phases.
-         If we are not at the pattern start, compile code to change the ims
+         If we are not at the pattern start, reset the greedy defaults and the
-         options if this setting actually changes any of them, and reset the
+         case value for firstbyte and reqbyte. */
-         greedy defaults and the case value for firstbyte and reqbyte. */
          if (*ptr == CHAR_RIGHT_PARENTHESIS)
            {
-Line 5585 
 for (;; ptr++)
+Line 5860 
 for (;; ptr++)
              }
            else
              {
-             if ((options & PCRE_IMS) != (newoptions & PCRE_IMS))
-               {
-               *code++ = OP_OPT;
-               *code++ = newoptions & PCRE_IMS;
-               }
              greedy_default = ((newoptions & PCRE_UNGREEDY) != 0);
              greedy_non_default = greedy_default ^ 1;
              req_caseopt = ((newoptions & PCRE_CASELESS) != 0)? REQ_CASELESS : 0;
              }
            /* Change options at this level, and pass them back for use
-           in subsequent branches. When not at the start of the pattern, this
+           in subsequent branches. */
-           information is also necessary so that a resetting item can be
-           compiled at the end of a group (if we are in a group). */
            *optionsptr = options = newoptions;
            previous = NULL;       /* This item can't be repeated */
-Line 5634 
 for (;; ptr++)
+Line 5902 
 for (;; ptr++)
        skipbytes = 2;
        }
-     /* Process nested bracketed regex. Assertions may not be repeated, but
+     /* Process nested bracketed regex. Assertions used not to be repeatable,
-     other kinds can be. All their opcodes are >= OP_ONCE. We copy code into a
+     but this was changed for Perl compatibility, so all kinds can now be
-     non-register variable in order to be able to pass its address because some
+     repeated. We copy code into a non-register variable (tempcode) in order to
-     compilers complain otherwise. Pass in a new setting for the ims options if
+     be able to pass its address because some compilers complain otherwise. */
-     they have changed. */
-     previous = (bravalue >= OP_ONCE)? code : NULL;
+     previous = code;                      /* For handling repetition */
      *code = bravalue;
      tempcode = code;
-     tempreqvary = cd->req_varyopt;     /* Save value before bracket */
+     tempreqvary = cd->req_varyopt;        /* Save value before bracket */
-     length_prevgroup = 0;              /* Initialize for pre-compile phase */
+     tempbracount = cd->bracount;          /* Save value before bracket */
+     length_prevgroup = 0;                 /* Initialize for pre-compile phase */
      if (!compile_regex(
-          newoptions,                   /* The complete new option state */
+          newoptions,                      /* The complete new option state */
-          options & PCRE_IMS,           /* The previous ims option state */
+          &tempcode,                       /* Where to put code (updated) */
-          &tempcode,                    /* Where to put code (updated) */
+          &ptr,                            /* Input pointer (updated) */
-          &ptr,                         /* Input pointer (updated) */
+          errorcodeptr,                    /* Where to put an error message */
-          errorcodeptr,                 /* Where to put an error message */
           (bravalue == OP_ASSERTBACK ||
            bravalue == OP_ASSERTBACK_NOT), /* TRUE if back assert */
-          reset_bracount,               /* True if (?| group */
+          reset_bracount,                  /* True if (?| group */
-          skipbytes,                    /* Skip over bracket number */
+          skipbytes,                       /* Skip over bracket number */
-          &subfirstbyte,                /* For possible first char */
+          cond_depth +
-          &subreqbyte,                  /* For possible last char */
+            ((bravalue == OP_COND)?1:0),   /* Depth of condition subpatterns */
-          bcptr,                        /* Current branch chain */
+          &subfirstbyte,                   /* For possible first char */
-          cd,                           /* Tables block */
+          &subreqbyte,                     /* For possible last char */
-          (lengthptr == NULL)? NULL :   /* Actual compile phase */
+          bcptr,                           /* Current branch chain */
-            &length_prevgroup           /* Pre-compile phase */
+          cd,                              /* Tables block */
+          (lengthptr == NULL)? NULL :      /* Actual compile phase */
+            &length_prevgroup              /* Pre-compile phase */
           ))
        goto FAILED;
+     /* If this was an atomic group and there are no capturing groups within it,
+     generate OP_ONCE_NC instead of OP_ONCE. */
+     if (bravalue == OP_ONCE && cd->bracount <= tempbracount)
+       *code = OP_ONCE_NC;
+     if (bravalue >= OP_ASSERT && bravalue <= OP_ASSERTBACK_NOT)
+       cd->assert_depth -= 1;
      /* 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
+     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)
+     The pattern pointer (ptr) is on the bracket.
-     is on the bracket. */
-     /* If this is a conditional bracket, check that there are no more than
+     If this is a conditional bracket, check that there are no more than
      two branches in the group, or just one if it's a DEFINE group. We do this
      in the real compile phase, not in the pre-pass, where the whole group may
      not be available. */
-Line 5735 
 for (;; ptr++)
+Line 6012 
 for (;; ptr++)
          goto FAILED;
          }
        *lengthptr += length_prevgroup - 2 - 2*LINK_SIZE;
-       *code++ = OP_BRA;
+       code++;   /* This already contains bravalue */
        PUTINC(code, 0, 1 + LINK_SIZE);
        *code++ = OP_KET;
        PUTINC(code, 0, 1 + LINK_SIZE);
-Line 5903 
 for (;; ptr++)
+Line 6180 
 for (;; ptr++)
          }
        /* \k<name> or \k'name' is a back reference by name (Perl syntax).
-       We also support \k{name} (.NET syntax) */
+       We also support \k{name} (.NET syntax).  */
-       if (-c == ESC_k && (ptr[1] == CHAR_LESS_THAN_SIGN ||
+       if (-c == ESC_k)
-           ptr[1] == CHAR_APOSTROPHE || ptr[1] == CHAR_LEFT_CURLY_BRACKET))
          {
+         if ((ptr[1] != CHAR_LESS_THAN_SIGN &&
+           ptr[1] != CHAR_APOSTROPHE && ptr[1] != CHAR_LEFT_CURLY_BRACKET))
+           {
+           *errorcodeptr = ERR69;
+           break;
+           }
          is_recurse = FALSE;
          terminator = (*(++ptr) == CHAR_LESS_THAN_SIGN)?
            CHAR_GREATER_THAN_SIGN : (*ptr == CHAR_APOSTROPHE)?
-Line 5927 
 for (;; ptr++)
+Line 6209 
 for (;; ptr++)
          HANDLE_REFERENCE:    /* Come here from named backref handling */
          if (firstbyte == REQ_UNSET) firstbyte = REQ_NONE;
          previous = code;
-         *code++ = OP_REF;
+         *code++ = ((options & PCRE_CASELESS) != 0)? OP_REFI : OP_REF;
          PUT2INC(code, 0, recno);
          cd->backref_map |= (recno < 32)? (1 << recno) : 1;
          if (recno > cd->top_backref) cd->top_backref = recno;
-Line 6035 
 for (;; ptr++)
+Line 6317 
 for (;; ptr++)
      ONE_CHAR:
      previous = code;
-     *code++ = ((options & PCRE_CASELESS) != 0)? OP_CHARNC : OP_CHAR;
+     *code++ = ((options & PCRE_CASELESS) != 0)? OP_CHARI : OP_CHAR;
      for (c = 0; c < mclength; c++) *code++ = mcbuffer[c];
      /* Remember if \r or \n were seen */
-Line 6064 
 for (;; ptr++)
+Line 6346 
 for (;; ptr++)
        else firstbyte = reqbyte = REQ_NONE;
        }
-     /* firstbyte was previously set; we can set reqbyte only the length is
+     /* firstbyte was previously set; we can set reqbyte only if the length is
 or the matching is caseful. */
      else
-Line 6099 
 return FALSE;
+Line 6381 
 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.
- 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.
  This function is used during the pre-compile phase when we are trying to find
  out the amount of memory needed, as well as during the real compile phase. The
  value of lengthptr distinguishes the two phases.
  Arguments:
    options        option bits, including any changes for this subpattern
-   oldims         previous settings of ims option bits
    codeptr        -> the address of the current code pointer
    ptrptr         -> the address of the current pattern pointer
    errorcodeptr   -> pointer to error code variable
    lookbehind     TRUE if this is a lookbehind assertion
    reset_bracount TRUE to reset the count for each branch
    skipbytes      skip this many bytes at start (for brackets and OP_COND)
+   cond_depth     depth of nesting for conditional subpatterns
    firstbyteptr   place to put the first required character, or a negative number
    reqbyteptr     place to put the last required character, or a negative number
    bcptr          pointer to the chain of currently open branches
-Line 6128 
 Returns:         TRUE on success
+Line 6405 
 Returns:         TRUE on success
  */
  static BOOL
- compile_regex(int options, int oldims, uschar **codeptr, const uschar **ptrptr,
+ compile_regex(int options, uschar **codeptr, const uschar **ptrptr,
    int *errorcodeptr, BOOL lookbehind, BOOL reset_bracount, int skipbytes,
-   int *firstbyteptr, int *reqbyteptr, branch_chain *bcptr, compile_data *cd,
+   int cond_depth, int *firstbyteptr, int *reqbyteptr, branch_chain *bcptr,
-   int *lengthptr)
+   compile_data *cd, int *lengthptr)
  {
  const uschar *ptr = *ptrptr;
  uschar *code = *codeptr;
-Line 6145 
 int branchfirstbyte, branchreqbyte;
+Line 6422 
 int branchfirstbyte, branchreqbyte;
  int length;
  int orig_bracount;
  int max_bracount;
- int old_external_options = cd->external_options;
  branch_chain bc;
  bc.outer = bcptr;
-Line 6169 
 pre-compile phase to find out whether an
+Line 6445 
 pre-compile phase to find out whether an
  /* If this is a capturing subpattern, add to the chain of open capturing items
  so that we can detect them if (*ACCEPT) is encountered. This is also used to
- detect groups that contain recursive back references to themselves. */
+ detect groups that contain recursive back references to themselves. Note that
+ only OP_CBRA need be tested here; changing this opcode to one of its variants,
+ e.g. OP_SCBRAPOS, happens later, after the group has been compiled. */
  if (*code == OP_CBRA)
    {
-Line 6195 
 for (;;)
+Line 6473 
 for (;;)
    if (reset_bracount) cd->bracount = orig_bracount;
-   /* Handle a change of ims options at the start of the branch */
-   if ((options & PCRE_IMS) != oldims)
-     {
-     *code++ = OP_OPT;
-     *code++ = options & PCRE_IMS;
-     length += 2;
-     }
    /* Set up dummy OP_REVERSE if lookbehind assertion */
    if (lookbehind)
-Line 6218 
 for (;;)
+Line 6487 
 for (;;)
    into the length. */
    if (!compile_branch(&options, &code, &ptr, errorcodeptr, &branchfirstbyte,
-         &branchreqbyte, &bc, cd, (lengthptr == NULL)? NULL : &length))
+         &branchreqbyte, &bc, cond_depth, cd,
+         (lengthptr == NULL)? NULL : &length))
      {
      *ptrptr = ptr;
      return FALSE;
      }
-   /* If the external options have changed during this branch, it means that we
-   are at the top level, and a leading option setting has been encountered. We
-   need to re-set the original option values to take account of this so that,
-   during the pre-compile phase, we know to allow for a re-set at the start of
-   subsequent branches. */
-   if (old_external_options != cd->external_options)
-     oldims = cd->external_options & PCRE_IMS;
    /* Keep the highest bracket count in case (?| was used and some branch
    has fewer than the rest. */
-Line 6293 
 for (;;)
+Line 6554 
 for (;;)
        {
        int fixed_length;
        *code = OP_END;
-       fixed_length = find_fixedlength(last_branch, options, FALSE, cd);
+       fixed_length = find_fixedlength(last_branch,  (options & PCRE_UTF8) != 0,
+         FALSE, cd);
        DPRINTF(("fixed length = %d\n", fixed_length));
        if (fixed_length == -3)
          {
-Line 6314 
 for (;;)
+Line 6576 
 for (;;)
    of offsets, with the field in the BRA item now becoming an offset to the
    first alternative. If there are no alternatives, it points to the end of the
    group. The length in the terminating ket is always the length of the whole
-   bracketed item. If any of the ims options were changed inside the group,
+   bracketed item. Return leaving the pointer at the terminating char. */
-   compile a resetting op-code following, except at the very end of the pattern.
-   Return leaving the pointer at the terminating char. */
    if (*ptr != CHAR_VERTICAL_LINE)
      {
-Line 6360 
 for (;;)
+Line 6620 
 for (;;)
        cd->open_caps = cd->open_caps->next;
        }
-     /* Reset options if needed. */
-     if ((options & PCRE_IMS) != oldims && *ptr == CHAR_RIGHT_PARENTHESIS)
-       {
-       *code++ = OP_OPT;
-       *code++ = oldims;
-       length += 2;
-       }
      /* Retain the highest bracket number, in case resetting was used. */
      cd->bracount = max_bracount;
-Line 6428 
 for (;;)
+Line 6679 
 for (;;)
  /* Try to find out if this is an anchored regular expression. Consider each
  alternative branch. If they all start with OP_SOD or OP_CIRC, or with a bracket
  all of whose alternatives start with OP_SOD or OP_CIRC (recurse ad lib), then
- it's anchored. However, if this is a multiline pattern, then only OP_SOD
+ it's anchored. However, if this is a multiline pattern, then only OP_SOD will
- counts, since OP_CIRC can match in the middle.
+ be found, because ^ generates OP_CIRCM in that mode.
  We can also consider a regex to be anchored if OP_SOM starts all its branches.
  This is the code for \G, which means "match at start of match position, taking
-Line 6450 
 of the more common cases more precisely.
+Line 6701 
 of the more common cases more precisely.
  Arguments:
    code           points to start of expression (the bracket)
-   options        points to the options setting
    bracket_map    a bitmap of which brackets we are inside while testing; this
                    handles up to substring 31; after that we just have to take
                    the less precise approach
-Line 6460 
 Returns:     TRUE or FALSE
+Line 6710 
 Returns:     TRUE or FALSE
  */
  static BOOL
- is_anchored(register const uschar *code, int *options, unsigned int bracket_map,
+ is_anchored(register const uschar *code, unsigned int bracket_map,
    unsigned int backref_map)
  {
  do {
     const uschar *scode = first_significant_code(code + _pcre_OP_lengths[*code],
-      options, PCRE_MULTILINE, FALSE);
+      FALSE);
     register int op = *scode;
     /* Non-capturing brackets */
-    if (op == OP_BRA)
+    if (op == OP_BRA  || op == OP_BRAPOS ||
+        op == OP_SBRA || op == OP_SBRAPOS)
       {
-      if (!is_anchored(scode, options, bracket_map, backref_map)) return FALSE;
+      if (!is_anchored(scode, bracket_map, backref_map)) return FALSE;
       }
     /* Capturing brackets */
-    else if (op == OP_CBRA)
+    else if (op == OP_CBRA  || op == OP_CBRAPOS ||
+             op == OP_SCBRA || op == OP_SCBRAPOS)
       {
       int n = GET2(scode, 1+LINK_SIZE);
       int new_map = bracket_map | ((n < 32)? (1 << n) : 1);
-      if (!is_anchored(scode, options, new_map, backref_map)) return FALSE;
+      if (!is_anchored(scode, new_map, backref_map)) return FALSE;
       }
     /* Other brackets */
-    else if (op == OP_ASSERT || op == OP_ONCE || op == OP_COND)
+    else if (op == OP_ASSERT || op == OP_ONCE || op == OP_ONCE_NC ||
+             op == OP_COND)
       {
-      if (!is_anchored(scode, options, bracket_map, backref_map)) return FALSE;
+      if (!is_anchored(scode, bracket_map, backref_map)) return FALSE;
       }
     /* .* is not anchored unless DOTALL is set (which generates OP_ALLANY) and
-Line 6503 
 do {
+Line 6756 
 do {
     /* Check for explicit anchoring */
-    else if (op != OP_SOD && op != OP_SOM &&
+    else if (op != OP_SOD && op != OP_SOM && op != OP_CIRC) return FALSE;
-            ((*options & PCRE_MULTILINE) != 0 || op != OP_CIRC))
-      return FALSE;
     code += GET(code, 1);
     }
  while (*code == OP_ALT);   /* Loop for each alternative */
-Line 6541 
 is_startline(const uschar *code, unsigne
+Line 6792 
 is_startline(const uschar *code, unsigne
  {
  do {
     const uschar *scode = first_significant_code(code + _pcre_OP_lengths[*code],
-      NULL, 0, FALSE);
+      FALSE);
     register int op = *scode;
     /* If we are at the start of a conditional assertion group, *both* the
-Line 6568 
 do {
+Line 6819 
 do {
         scode += 1 + LINK_SIZE;
         break;
         }
-      scode = first_significant_code(scode, NULL, 0, FALSE);
+      scode = first_significant_code(scode, FALSE);
       op = *scode;
       }
     /* Non-capturing brackets */
-    if (op == OP_BRA)
+    if (op == OP_BRA  || op == OP_BRAPOS ||
+        op == OP_SBRA || op == OP_SBRAPOS)
       {
       if (!is_startline(scode, bracket_map, backref_map)) return FALSE;
       }
     /* Capturing brackets */
-    else if (op == OP_CBRA)
+    else if (op == OP_CBRA  || op == OP_CBRAPOS ||
+             op == OP_SCBRA || op == OP_SCBRAPOS)
       {
       int n = GET2(scode, 1+LINK_SIZE);
       int new_map = bracket_map | ((n < 32)? (1 << n) : 1);
-Line 6590 
 do {
+Line 6843 
 do {
     /* Other brackets */
-    else if (op == OP_ASSERT || op == OP_ONCE)
+    else if (op == OP_ASSERT || op == OP_ONCE || op == OP_ONCE_NC)
       {
       if (!is_startline(scode, bracket_map, backref_map)) return FALSE;
       }
-Line 6605 
 do {
+Line 6858 
 do {
     /* Check for explicit circumflex */
-    else if (op != OP_CIRC) return FALSE;
+    else if (op != OP_CIRC && op != OP_CIRCM) return FALSE;
     /* Move on to the next alternative */
-Line 6631 
 we return that char, otherwise -1.
+Line 6884 
 we return that char, otherwise -1.
  Arguments:
    code       points to start of expression (the bracket)
-   options    pointer to the options (used to check casing changes)
    inassert   TRUE if in an assertion
  Returns:     -1 or the fixed first char
  */
  static int
- find_firstassertedchar(const uschar *code, int *options, BOOL inassert)
+ find_firstassertedchar(const uschar *code, BOOL inassert)
  {
  register int c = -1;
  do {
     int d;
-    const uschar *scode =
+    int xl = (*code == OP_CBRA || *code == OP_SCBRA ||
-      first_significant_code(code + 1+LINK_SIZE, options, PCRE_CASELESS, TRUE);
+              *code == OP_CBRAPOS || *code == OP_SCBRAPOS)? 2:0;
+    const uschar *scode = first_significant_code(code + 1+LINK_SIZE + xl, TRUE);
     register int op = *scode;
     switch(op)
-Line 6653 
 do {
+Line 6906 
 do {
       return -1;
       case OP_BRA:
+      case OP_BRAPOS:
       case OP_CBRA:
+      case OP_SCBRA:
+      case OP_CBRAPOS:
+      case OP_SCBRAPOS:
       case OP_ASSERT:
       case OP_ONCE:
+      case OP_ONCE_NC:
       case OP_COND:
-      if ((d = find_firstassertedchar(scode, options, op == OP_ASSERT)) < 0)
+      if ((d = find_firstassertedchar(scode, op == OP_ASSERT)) < 0)
         return -1;
       if (c < 0) c = d; else if (c != d) return -1;
       break;
-      case OP_EXACT:       /* Fall through */
+      case OP_EXACT:
       scode += 2;
+      /* Fall through */
       case OP_CHAR:
-      case OP_CHARNC:
       case OP_PLUS:
       case OP_MINPLUS:
       case OP_POSPLUS:
       if (!inassert) return -1;
-      if (c < 0)
+      if (c < 0) c = scode[1];
-        {
+        else if (c != scode[1]) return -1;
-        c = scode[1];
+      break;
-        if ((*options & PCRE_CASELESS) != 0) c |= REQ_CASELESS;
-        }
+      case OP_EXACTI:
-      else if (c != scode[1]) return -1;
+      scode += 2;
+      /* Fall through */
+      case OP_CHARI:
+      case OP_PLUSI:
+      case OP_MINPLUSI:
+      case OP_POSPLUSI:
+      if (!inassert) return -1;
+      if (c < 0) c = scode[1] | REQ_CASELESS;
+        else if (c != scode[1]) return -1;
       break;
       }
-Line 6799 
 while (ptr[skipatstart] == CHAR_LEFT_PAR
+Line 7066 
 while (ptr[skipatstart] == CHAR_LEFT_PAR
      { skipatstart += 7; options |= PCRE_UTF8; continue; }
    else if (strncmp((char *)(ptr+skipatstart+2), STRING_UCP_RIGHTPAR, 4) == 0)
      { skipatstart += 6; options |= PCRE_UCP; continue; }
+   else if (strncmp((char *)(ptr+skipatstart+2), STRING_NO_START_OPT_RIGHTPAR, 13) == 0)
+     { skipatstart += 15; options |= PCRE_NO_START_OPTIMIZE; continue; }
    if (strncmp((char *)(ptr+skipatstart+2), STRING_CR_RIGHTPAR, 3) == 0)
      { skipatstart += 5; newnl = PCRE_NEWLINE_CR; }
-Line 6825 
 while (ptr[skipatstart] == CHAR_LEFT_PAR
+Line 7094 
 while (ptr[skipatstart] == CHAR_LEFT_PAR
  utf8 = (options & PCRE_UTF8) != 0;
- /* Can't support UTF8 unless PCRE has been compiled to include the code. */
+ /* Can't support UTF8 unless PCRE has been compiled to include the code. The
+ return of an error code from _pcre_valid_utf8() is a new feature, introduced in
+ release 8.13. It is passed back from pcre_[dfa_]exec(), but at the moment is
+ not used here. */
  #ifdef SUPPORT_UTF8
  if (utf8 && (options & PCRE_NO_UTF8_CHECK) == 0 &&
-      (*erroroffset = _pcre_valid_utf8((USPTR)pattern, -1)) >= 0)
+      (errorcode = _pcre_valid_utf8((USPTR)pattern, -1, erroroffset)) != 0)
    {
    errorcode = ERR44;
    goto PCRE_EARLY_ERROR_RETURN2;
-Line 6854 
 if ((options & PCRE_UCP) != 0)
+Line 7126 
 if ((options & PCRE_UCP) != 0)
  /* Check validity of \R options. */
- switch (options & (PCRE_BSR_ANYCRLF|PCRE_BSR_UNICODE))
+ if ((options & (PCRE_BSR_ANYCRLF|PCRE_BSR_UNICODE)) ==
+      (PCRE_BSR_ANYCRLF|PCRE_BSR_UNICODE))
    {
-   case 0:
+   errorcode = ERR56;
-   case PCRE_BSR_ANYCRLF:
+   goto PCRE_EARLY_ERROR_RETURN;
-   case PCRE_BSR_UNICODE:
-   break;
-   default: errorcode = ERR56; goto PCRE_EARLY_ERROR_RETURN;
    }
  /* Handle different types of newline. The three bits give seven cases. The
-Line 6945 
 outside can help speed up starting point
+Line 7215 
 outside can help speed up starting point
  ptr += skipatstart;
  code = cworkspace;
  *code = OP_BRA;
- (void)compile_regex(cd->external_options, cd->external_options & PCRE_IMS,
+ (void)compile_regex(cd->external_options, &code, &ptr, &errorcode, FALSE,
-   &code, &ptr, &errorcode, FALSE, FALSE, 0, &firstbyte, &reqbyte, NULL, cd,
+   FALSE, 0, 0, &firstbyte, &reqbyte, NULL, cd, &length);
-   &length);
  if (errorcode != 0) goto PCRE_EARLY_ERROR_RETURN;
  DPRINTF(("end pre-compile: length=%d workspace=%d\n", length,
-Line 7001 
 field; this time it's used for rememberi
+Line 7270 
 field; this time it's used for rememberi
  */
  cd->final_bracount = cd->bracount;  /* Save for checking forward references */
+ cd->assert_depth = 0;
  cd->bracount = 0;
  cd->names_found = 0;
  cd->name_table = (uschar *)re + re->name_table_offset;
-Line 7019 
 of the function here. */
+Line 7289 
 of the function here. */
  ptr = (const uschar *)pattern + skipatstart;
  code = (uschar *)codestart;
  *code = OP_BRA;
- (void)compile_regex(re->options, re->options & PCRE_IMS, &code, &ptr,
+ (void)compile_regex(re->options, &code, &ptr, &errorcode, FALSE, FALSE, 0, 0,
-   &errorcode, FALSE, FALSE, 0, &firstbyte, &reqbyte, NULL, cd, NULL);
+   &firstbyte, &reqbyte, NULL, cd, NULL);
  re->top_bracket = cd->bracount;
  re->top_backref = cd->top_backref;
  re->flags = cd->external_flags;
- if (cd->had_accept) reqbyte = -1;   /* Must disable after (*ACCEPT) */
+ if (cd->had_accept) reqbyte = REQ_NONE;   /* Must disable after (*ACCEPT) */
  /* If not reached end of pattern on success, there's an excess bracket. */
-Line 7086 
 if (cd->check_lookbehind)
+Line 7356 
 if (cd->check_lookbehind)
        uschar *be = cc - 1 - LINK_SIZE + GET(cc, -LINK_SIZE);
        int end_op = *be;
        *be = OP_END;
-       fixed_length = find_fixedlength(cc, re->options, TRUE, cd);
+       fixed_length = find_fixedlength(cc, (re->options & PCRE_UTF8) != 0, TRUE,
+         cd);
        *be = end_op;
        DPRINTF(("fixed length = %d\n", fixed_length));
        if (fixed_length < 0)
-Line 7125 
 start with ^. and also when all branches
+Line 7396 
 start with ^. and also when all branches
  if ((re->options & PCRE_ANCHORED) == 0)
    {
-   int temp_options = re->options;   /* May get changed during these scans */
+   if (is_anchored(codestart, 0, cd->backref_map))
-   if (is_anchored(codestart, &temp_options, 0, cd->backref_map))
      re->options |= PCRE_ANCHORED;
    else
      {
      if (firstbyte < 0)
-       firstbyte = find_firstassertedchar(codestart, &temp_options, FALSE);
+       firstbyte = find_firstassertedchar(codestart, FALSE);
      if (firstbyte >= 0)   /* Remove caseless flag for non-caseable chars */
        {
        int ch = firstbyte & 255;

 Legend:



Removed from v.544
 


changed lines


 
Added in v.723
 Legend:



Removed from v.544
 


changed lines


 
Added in v.723
-Removed from v.544
+Added in v.723

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