init version.

[bush.git] / lib / glob / sm_loop.c

/* Copyright (C) 1991-2020 Free Software Foundation, Inc.

   This file is part of GNU Bush, the Bourne Again SHell.
   
   Bush is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Bush is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Bush.  If not, see <http://www.gnu.org/licenses/>.
*/

struct STRUCT
{
  CHAR *pattern;
  CHAR *string;
};

int FCT PARAMS((CHAR *, CHAR *, int));

static int GMATCH PARAMS((CHAR *, CHAR *, CHAR *, CHAR *, struct STRUCT *, int));
static CHAR *PARSE_COLLSYM PARAMS((CHAR *, INT *));
static CHAR *BRACKMATCH PARAMS((CHAR *, U_CHAR, int));
static int EXTMATCH PARAMS((INT, CHAR *, CHAR *, CHAR *, CHAR *, int));

extern void DEQUOTE_PATHNAME PARAMS((CHAR *));

/*static*/ CHAR *PATSCAN PARAMS((CHAR *, CHAR *, INT));

int
FCT (pattern, string, flags)
     CHAR *pattern;
     CHAR *string;
     int flags;
{
  CHAR *se, *pe;

  if (string == 0 || pattern == 0)
    return FNM_NOMATCH;

  se = string + STRLEN ((XCHAR *)string);
  pe = pattern + STRLEN ((XCHAR *)pattern);

  return (GMATCH (string, se, pattern, pe, (struct  STRUCT *)NULL, flags));
}

/* Match STRING against the filename pattern PATTERN, returning zero if
   it matches, FNM_NOMATCH if not.  */
static int
GMATCH (string, se, pattern, pe, ends, flags)
     CHAR *string, *se;
     CHAR *pattern, *pe;
     struct STRUCT *ends;
     int flags;
{
  CHAR *p, *n;          /* pattern, string */
  INT c;                /* current pattern character - XXX U_CHAR? */
  INT sc;               /* current string character - XXX U_CHAR? */

  p = pattern;
  n = string;

  if (string == 0 || pattern == 0)
    return FNM_NOMATCH;

#if DEBUG_MATCHING
fprintf(stderr, "gmatch: string = %s; se = %s\n", string, se);
fprintf(stderr, "gmatch: pattern = %s; pe = %s\n", pattern, pe);
#endif

  while (p < pe)
    {
      c = *p++;
      c = FOLD (c);

      sc = n < se ? *n : '\0';

#ifdef EXTENDED_GLOB
      /* EXTMATCH () will handle recursively calling GMATCH, so we can
         just return what EXTMATCH() returns. */
      if ((flags & FNM_EXTMATCH) && *p == L('(') &&
          (c == L('+') || c == L('*') || c == L('?') || c == L('@') || c == L('!'))) /* ) */
        {
          int lflags;
          /* If we're not matching the start of the string, we're not
             concerned about the special cases for matching `.' */
          lflags = (n == string) ? flags : (flags & ~FNM_PERIOD);
          return (EXTMATCH (c, n, se, p, pe, lflags));
        }
#endif /* EXTENDED_GLOB */

      switch (c)
        {
        case L('?'):            /* Match single character */
          if (sc == '\0')
            return FNM_NOMATCH;
          else if ((flags & FNM_PATHNAME) && sc == L('/'))
            /* If we are matching a pathname, `?' can never match a `/'. */
            return FNM_NOMATCH;
          else if ((flags & FNM_PERIOD) && sc == L('.') &&
                   (n == string || ((flags & FNM_PATHNAME) && n[-1] == L('/'))))
            /* `?' cannot match a `.' if it is the first character of the
               string or if it is the first character following a slash and
               we are matching a pathname. */
            return FNM_NOMATCH;
          break;

        case L('\\'):           /* backslash escape removes special meaning */
          if (p == pe && sc == '\\' && (n+1 == se))
            break;

          if (p == pe)
            return FNM_NOMATCH;

          if ((flags & FNM_NOESCAPE) == 0)
            {
              c = *p++;
              /* A trailing `\' cannot match. */
              if (p > pe)
                return FNM_NOMATCH;
              c = FOLD (c);
            }
          if (FOLD (sc) != (U_CHAR)c)
            return FNM_NOMATCH;
          break;

        case L('*'):            /* Match zero or more characters */
          /* See below for the reason for using this. It avoids backtracking
             back to a previous `*'.  Picked up from glibc. */
          if (ends != NULL)
            {
              ends->pattern = p - 1;
              ends->string = n;
              return (0);
            }

          if ((flags & FNM_PERIOD) && sc == L('.') &&
              (n == string || ((flags & FNM_PATHNAME) && n[-1] == L('/'))))
            /* `*' cannot match a `.' if it is the first character of the
               string or if it is the first character following a slash and
               we are matching a pathname. */
            return FNM_NOMATCH;

          if (p == pe)
            return 0;

          /* Collapse multiple consecutive `*' and `?', but make sure that
             one character of the string is consumed for each `?'. */
          for (c = *p++; (c == L('?') || c == L('*')); c = *p++)
            {
              if ((flags & FNM_PATHNAME) && sc == L('/'))
                /* A slash does not match a wildcard under FNM_PATHNAME. */
                return FNM_NOMATCH;
#ifdef EXTENDED_GLOB
              else if ((flags & FNM_EXTMATCH) && c == L('?') && *p == L('(')) /* ) */
                {
                  CHAR *newn;

                  /* We can match 0 or 1 times.  If we match, return success */
                  if (EXTMATCH (c, n, se, p, pe, flags) == 0)
                    return (0);

                  /* We didn't match the extended glob pattern, but
                     that's OK, since we can match 0 or 1 occurrences.
                     We need to skip the glob pattern and see if we
                     match the rest of the string. */
                  newn = PATSCAN (p + 1, pe, 0);
                  /* If NEWN is 0, we have an ill-formed pattern. */
                  p = newn ? newn : pe;
                }
#endif
              else if (c == L('?'))
                {
                  if (sc == L('\0'))
                    return FNM_NOMATCH;
                  /* One character of the string is consumed in matching
                     this ? wildcard, so *??? won't match if there are
                     fewer than three characters. */
                  n++;
                  sc = n < se ? *n : '\0';
                }

#ifdef EXTENDED_GLOB
              /* Handle ******(patlist) */
              if ((flags & FNM_EXTMATCH) && c == L('*') && *p == L('('))  /*)*/
                {
                  CHAR *newn;
                  /* We need to check whether or not the extended glob
                     pattern matches the remainder of the string.
                     If it does, we match the entire pattern. */
                  for (newn = n; newn < se; ++newn)
                    {
                      if (EXTMATCH (c, newn, se, p, pe, flags) == 0)
                        return (0);
                    }
                  /* We didn't match the extended glob pattern, but
                     that's OK, since we can match 0 or more occurrences.
                     We need to skip the glob pattern and see if we
                     match the rest of the string. */
                  newn = PATSCAN (p + 1, pe, 0);
                  /* If NEWN is 0, we have an ill-formed pattern. */
                  p = newn ? newn : pe;
                }
#endif
              if (p == pe)
                break;
            }

          /* The wildcards are the last element of the pattern.  The name
             cannot match completely if we are looking for a pathname and
             it contains another slash, unless FNM_LEADING_DIR is set. */
          if (c == L('\0'))
            {
              int r = (flags & FNM_PATHNAME) == 0 ? 0 : FNM_NOMATCH;
              if (flags & FNM_PATHNAME)
                {
                  if (flags & FNM_LEADING_DIR)
                    r = 0;
                  else if (MEMCHR (n, L('/'), se - n) == NULL)
                    r = 0;
                }
              return r;
            }

          /* If we've hit the end of the pattern and the last character of
             the pattern was handled by the loop above, we've succeeded.
             Otherwise, we need to match that last character. */
          if (p == pe && (c == L('?') || c == L('*')))
            return (0);

          /* If we've hit the end of the string and the rest of the pattern
             is something that matches the empty string, we can succeed. */
#if defined (EXTENDED_GLOB)
          if (n == se && ((flags & FNM_EXTMATCH) && (c == L('!') || c == L('?')) && *p == L('(')))
            {
              --p;
              if (EXTMATCH (c, n, se, p, pe, flags) == 0)
                return (c == L('!') ? FNM_NOMATCH : 0);
              return (c == L('!') ? 0 : FNM_NOMATCH);
            }
#endif

          /* If we stop at a slash in the pattern and we are looking for a
             pathname ([star]/foo), then consume enough of the string to stop
             at any slash and then try to match the rest of the pattern.  If
             the string doesn't contain a slash, fail */
          if (c == L('/') && (flags & FNM_PATHNAME))
            {
              while (n < se && *n != L('/'))
                ++n;
              if (n < se && *n == L('/') && (GMATCH (n+1, se, p, pe, NULL, flags) == 0))
                return 0;
              return FNM_NOMATCH;       /* XXX */
            }

          /* General case, use recursion. */
          {
            U_CHAR c1;
            const CHAR *endp;
            struct STRUCT end;

            end.pattern = NULL;
            endp = MEMCHR (n, (flags & FNM_PATHNAME) ? L('/') : L('\0'), se - n);
            if (endp == 0)
              endp = se;

            c1 = ((flags & FNM_NOESCAPE) == 0 && c == L('\\')) ? *p : c;
            c1 = FOLD (c1);
            for (--p; n < endp; ++n)
              {
                /* Only call strmatch if the first character indicates a
                   possible match.  We can check the first character if
                   we're not doing an extended glob match. */
                if ((flags & FNM_EXTMATCH) == 0 && c != L('[') && FOLD (*n) != c1) /*]*/
                  continue;

                /* If we're doing an extended glob match and the pattern is not
                   one of the extended glob patterns, we can check the first
                   character. */
                if ((flags & FNM_EXTMATCH) && p[1] != L('(') && /*)*/
                    STRCHR (L("?*+@!"), *p) == 0 && c != L('[') && FOLD (*n) != c1) /*]*/
                  continue;

                /* Otherwise, we just recurse. */
                if (GMATCH (n, se, p, pe, &end, flags & ~FNM_PERIOD) == 0)
                  {
                    if (end.pattern == NULL)
                      return (0);
                    break;
                  }
              }
            /* This is a clever idea from glibc, used to avoid backtracking
               to a `*' that appears earlier in the pattern.  We get away
               without saving se and pe because they are always the same,
               even in the recursive calls to gmatch */ 
            if (end.pattern != NULL)
              {
                p = end.pattern;
                n = end.string;
                continue;
              }

            return FNM_NOMATCH;
          }

        case L('['):
          {
            if (sc == L('\0') || n == se)
              return FNM_NOMATCH;

            /* A character class cannot match a `.' if it is the first
               character of the string or if it is the first character
               following a slash and we are matching a pathname. */
            if ((flags & FNM_PERIOD) && sc == L('.') &&
                (n == string || ((flags & FNM_PATHNAME) && n[-1] == L('/'))))
              return (FNM_NOMATCH);

            p = BRACKMATCH (p, sc, flags);
            if (p == 0)
              return FNM_NOMATCH;
          }
          break;

        default:
          if ((U_CHAR)c != FOLD (sc))
            return (FNM_NOMATCH);
        }

      ++n;
    }

  if (n == se)
    return (0);

  if ((flags & FNM_LEADING_DIR) && *n == L('/'))
    /* The FNM_LEADING_DIR flag says that "foo*" matches "foobar/frobozz".  */
    return 0;
          
  return (FNM_NOMATCH);
}

/* Parse a bracket expression collating symbol ([.sym.]) starting at P, find
   the value of the symbol, and move P past the collating symbol expression.
   The value is returned in *VP, if VP is not null. */
static CHAR *
PARSE_COLLSYM (p, vp)
     CHAR *p;
     INT *vp;
{
  register int pc;
  INT val;

  p++;                          /* move past the `.' */
          
  for (pc = 0; p[pc]; pc++)
    if (p[pc] == L('.') && p[pc+1] == L(']'))
      break;
   if (p[pc] == 0)
    {
      if (vp)
        *vp = INVALID;
      return (p + pc);
    }
   val = COLLSYM (p, pc);
   if (vp)
     *vp = val;
   return (p + pc + 2);
}

/* Use prototype definition here because of type promotion. */
static CHAR *
#if defined (PROTOTYPES)
BRACKMATCH (CHAR *p, U_CHAR test, int flags)
#else
BRACKMATCH (p, test, flags)
     CHAR *p;
     U_CHAR test;
     int flags;
#endif
{
  register CHAR cstart, cend, c;
  register int not;    /* Nonzero if the sense of the character class is inverted.  */
  int brcnt, forcecoll, isrange;
  INT pc;
  CHAR *savep;
  CHAR *brchrp;
  U_CHAR orig_test;

  orig_test = test;
  test = FOLD (orig_test);

  savep = p;

  /* POSIX.2 3.13.1 says that an exclamation mark (`!') shall replace the
     circumflex (`^') in its role in a `nonmatching list'.  A bracket
     expression starting with an unquoted circumflex character produces
     unspecified results.  This implementation treats the two identically. */
  if (not = (*p == L('!') || *p == L('^')))
    ++p;

  c = *p++;
  for (;;)
    {
      /* Initialize cstart and cend in case `-' is the last
         character of the pattern. */
      cstart = cend = c;
      forcecoll = 0;

      /* POSIX.2 equivalence class:  [=c=].  See POSIX.2 2.8.3.2.  Find
         the end of the equivalence class, move the pattern pointer past
         it, and check for equivalence.  XXX - this handles only
         single-character equivalence classes, which is wrong, or at
         least incomplete. */
      if (c == L('[') && *p == L('=') && p[2] == L('=') && p[3] == L(']'))
        {
          pc = FOLD (p[1]);
          p += 4;
          if (COLLEQUIV (test, pc))
            {
/*[*/         /* Move past the closing `]', since the first thing we do at
                 the `matched:' label is back p up one. */
              p++;
              goto matched;
            }
          else
            {
              c = *p++;
              if (c == L('\0'))
                return ((test == L('[')) ? savep : (CHAR *)0); /*]*/
              c = FOLD (c);
              continue;
            }
        }

      /* POSIX.2 character class expression.  See POSIX.2 2.8.3.2. */
      if (c == L('[') && *p == L(':'))
        {
          CHAR *close, *ccname;

          pc = 0;       /* make sure invalid char classes don't match. */
          /* Find end of character class name */
          for (close = p + 1; *close != '\0'; close++)
            if (*close == L(':') && *(close+1) == L(']'))
              break;

          if (*close != L('\0'))
            {
              ccname = (CHAR *)malloc ((close - p) * sizeof (CHAR));
              if (ccname == 0)
                pc = 0;
              else
                {
                  bcopy (p + 1, ccname, (close - p - 1) * sizeof (CHAR));
                  *(ccname + (close - p - 1)) = L('\0');
                  /* As a result of a POSIX discussion, char class names are
                     allowed to be quoted (?) */
                  DEQUOTE_PATHNAME (ccname);
                  pc = IS_CCLASS (orig_test, (XCHAR *)ccname);
                }
              if (pc == -1)
                {
                  /* CCNAME is not a valid character class in the current
                     locale. In addition to noting no match (pc = 0), we have
                     a choice about what to do with the invalid charclass.
                     Posix leaves the behavior unspecified, but we're going
                     to skip over the charclass and keep going instead of
                     testing ORIG_TEST against each character in the class
                     string. If we don't want to do that, take out the update
                     of P. */
                  pc = 0;
                  p = close + 2;
                }
              else
                p = close + 2;          /* move past the closing `]' */

              free (ccname);
            }
            
          if (pc)
            {
/*[*/         /* Move past the closing `]', since the first thing we do at
                 the `matched:' label is back p up one. */
              p++;
              goto matched;
            }
          else
            {
              /* continue the loop here, since this expression can't be
                 the first part of a range expression. */
              c = *p++;
              if (c == L('\0'))
                return ((test == L('[')) ? savep : (CHAR *)0);
              else if (c == L(']'))
                break;
              c = FOLD (c);
              continue;
            }
        }
 
      /* POSIX.2 collating symbols.  See POSIX.2 2.8.3.2.  Find the end of
         the symbol name, make sure it is terminated by `.]', translate
         the name to a character using the external table, and do the
         comparison. */
      if (c == L('[') && *p == L('.'))
        {
          p = PARSE_COLLSYM (p, &pc);
          /* An invalid collating symbol cannot be the first point of a
             range.  If it is, we set cstart to one greater than `test',
             so any comparisons later will fail. */
          cstart = (pc == INVALID) ? test + 1 : pc;
          forcecoll = 1;
        }

      if (!(flags & FNM_NOESCAPE) && c == L('\\'))
        {
          if (*p == '\0')
            return (CHAR *)0;
          cstart = cend = *p++;
        }

      cstart = cend = FOLD (cstart);
      isrange = 0;

      /* POSIX.2 2.8.3.1.2 says: `An expression containing a `[' that
         is not preceded by a backslash and is not part of a bracket
         expression produces undefined results.'  This implementation
         treats the `[' as just a character to be matched if there is
         not a closing `]'. */
      if (c == L('\0'))
        return ((test == L('[')) ? savep : (CHAR *)0);

      c = *p++;
      c = FOLD (c);

      if (c == L('\0'))
        return ((test == L('[')) ? savep : (CHAR *)0);

      if ((flags & FNM_PATHNAME) && c == L('/'))
        /* [/] can never match when matching a pathname.  */
        return (CHAR *)0;

      /* This introduces a range, unless the `-' is the last
         character of the class.  Find the end of the range
         and move past it. */
      if (c == L('-') && *p != L(']'))
        {
          cend = *p++;
          if (!(flags & FNM_NOESCAPE) && cend == L('\\'))
            cend = *p++;
          if (cend == L('\0'))
            return (CHAR *)0;
          if (cend == L('[') && *p == L('.'))
            {
              p = PARSE_COLLSYM (p, &pc);
              /* An invalid collating symbol cannot be the second part of a
                 range expression.  If we get one, we set cend to one fewer
                 than the test character to make sure the range test fails. */
              cend = (pc == INVALID) ? test - 1 : pc;
              forcecoll = 1;
            }
          cend = FOLD (cend);

          c = *p++;

          /* POSIX.2 2.8.3.2:  ``The ending range point shall collate
             equal to or higher than the starting range point; otherwise
             the expression shall be treated as invalid.''  Note that this
             applies to only the range expression; the rest of the bracket
             expression is still checked for matches. */
          if (RANGECMP (cstart, cend, forcecoll) > 0)
            {
              if (c == L(']'))
                break;
              c = FOLD (c);
              continue;
            }
          isrange = 1;
        }

      if (isrange == 0 && test == cstart)
        goto matched;
      if (isrange && RANGECMP (test, cstart, forcecoll) >= 0 && RANGECMP (test, cend, forcecoll) <= 0)
        goto matched;

      if (c == L(']'))
        break;
    }
  /* No match. */
  return (!not ? (CHAR *)0 : p);

matched:
  /* Skip the rest of the [...] that already matched.  */
  c = *--p;
  brcnt = 1;
  brchrp = 0;
  while (brcnt > 0)
    {
      int oc;

      /* A `[' without a matching `]' is just another character to match. */
      if (c == L('\0'))
        return ((test == L('[')) ? savep : (CHAR *)0);

      oc = c;
      c = *p++;
      if (c == L('[') && (*p == L('=') || *p == L(':') || *p == L('.')))
        {
          brcnt++;
          brchrp = p++;         /* skip over the char after the left bracket */
          if ((c = *p) == L('\0'))
            return ((test == L('[')) ? savep : (CHAR *)0);
          /* If *brchrp == ':' we should check that the rest of the characters
             form a valid character class name. We don't do that yet, but we
             keep BRCHRP in case we want to. */
        }
      /* We only want to check brchrp if we set it above. */
      else if (c == L(']') && brcnt > 1 && brchrp != 0 && oc == *brchrp)
        {
          brcnt--;
          brchrp = 0;           /* just in case */
        }
      /* Left bracket loses its special meaning inside a bracket expression.
         It is only valid when followed by a `.', `=', or `:', which we check
         for above. Technically the right bracket can appear in a collating
         symbol, so we check for that here. Otherwise, it terminates the
         bracket expression. */
      else if (c == L(']') && (brchrp == 0 || *brchrp != L('.')) && brcnt >= 1)
        brcnt = 0;
      else if (!(flags & FNM_NOESCAPE) && c == L('\\'))
        {
          if (*p == '\0')
            return (CHAR *)0;
          /* XXX 1003.2d11 is unclear if this is right. */
          ++p;
        }
    }
  return (not ? (CHAR *)0 : p);
}

#if defined (EXTENDED_GLOB)
/* ksh-like extended pattern matching:

        [?*+@!](pat-list)

   where pat-list is a list of one or patterns separated by `|'.  Operation
   is as follows:

        ?(patlist)      match zero or one of the given patterns
        *(patlist)      match zero or more of the given patterns
        +(patlist)      match one or more of the given patterns
        @(patlist)      match exactly one of the given patterns
        !(patlist)      match anything except one of the given patterns
*/

/* Scan a pattern starting at STRING and ending at END, keeping track of
   embedded () and [].  If DELIM is 0, we scan until a matching `)'
   because we're scanning a `patlist'.  Otherwise, we scan until we see
   DELIM.  In all cases, we never scan past END.  The return value is the
   first character after the matching DELIM or NULL if the pattern is
   empty or invalid. */
/*static*/ CHAR *
PATSCAN (string, end, delim)
     CHAR *string, *end;
     INT delim;
{
  int pnest, bnest, skip;
  INT cchar;
  CHAR *s, c, *bfirst;

  pnest = bnest = skip = 0;
  cchar = 0;
  bfirst = NULL;

  if (string == end)
    return (NULL);

  for (s = string; c = *s; s++)
    {
      if (s >= end)
        return (s);
      if (skip)
        {
          skip = 0;
          continue;
        }
      switch (c)
        {
        case L('\\'):
          skip = 1;
          break;

        case L('\0'):
          return ((CHAR *)NULL);

        /* `[' is not special inside a bracket expression, but it may
           introduce one of the special POSIX bracket expressions
           ([.SYM.], [=c=], [: ... :]) that needs special handling. */
        case L('['):
          if (bnest == 0)
            {
              bfirst = s + 1;
              if (*bfirst == L('!') || *bfirst == L('^'))
                bfirst++;
              bnest++;
            }
          else if (s[1] == L(':') || s[1] == L('.') || s[1] == L('='))
            cchar = s[1];
          break;

        /* `]' is not special if it's the first char (after a leading `!'
           or `^') in a bracket expression or if it's part of one of the
           special POSIX bracket expressions ([.SYM.], [=c=], [: ... :]) */
        case L(']'):
          if (bnest)
            {
              if (cchar && s[-1] == cchar)
                cchar = 0;
              else if (s != bfirst)
                {
                  bnest--;
                  bfirst = 0;
                }
            }
          break;

        case L('('):
          if (bnest == 0)
            pnest++;
          break;

        case L(')'):
          if (bnest == 0 && pnest-- <= 0)
            return ++s;
          break;

        case L('|'):
          if (bnest == 0 && pnest == 0 && delim == L('|'))
            return ++s;
          break;
        }
    }

  return (NULL);
}

/* Return 0 if dequoted pattern matches S in the current locale. */
static int
STRCOMPARE (p, pe, s, se)
     CHAR *p, *pe, *s, *se;
{
  int ret;
  CHAR c1, c2;
  int l1, l2;

  l1 = pe - p;
  l2 = se - s;

  if (l1 != l2)
    return (FNM_NOMATCH);       /* unequal lengths, can't be identical */
  
  c1 = *pe;
  c2 = *se;

  if (c1 != 0)
    *pe = '\0';
  if (c2 != 0)
    *se = '\0';
    
#if HAVE_MULTIBYTE || defined (HAVE_STRCOLL)
  ret = STRCOLL ((XCHAR *)p, (XCHAR *)s);
#else
  ret = STRCMP ((XCHAR *)p, (XCHAR *)s);
#endif

  if (c1 != 0)
    *pe = c1;
  if (c2 != 0)
    *se = c2;

  return (ret == 0 ? ret : FNM_NOMATCH);
}

/* Match a ksh extended pattern specifier.  Return FNM_NOMATCH on failure or
   0 on success.  This is handed the entire rest of the pattern and string
   the first time an extended pattern specifier is encountered, so it calls
   gmatch recursively. */
static int
EXTMATCH (xc, s, se, p, pe, flags)
     INT xc;            /* select which operation */
     CHAR *s, *se;
     CHAR *p, *pe;
     int flags;
{
  CHAR *prest;                  /* pointer to rest of pattern */
  CHAR *psub;                   /* pointer to sub-pattern */
  CHAR *pnext;                  /* pointer to next sub-pattern */
  CHAR *srest;                  /* pointer to rest of string */
  int m1, m2, xflags;           /* xflags = flags passed to recursive matches */

#if DEBUG_MATCHING
fprintf(stderr, "extmatch: xc = %c\n", xc);
fprintf(stderr, "extmatch: s = %s; se = %s\n", s, se);
fprintf(stderr, "extmatch: p = %s; pe = %s\n", p, pe);
fprintf(stderr, "extmatch: flags = %d\n", flags);
#endif

  prest = PATSCAN (p + (*p == L('(')), pe, 0); /* ) */
  if (prest == 0)
    /* If PREST is 0, we failed to scan a valid pattern.  In this
       case, we just want to compare the two as strings. */
    return (STRCOMPARE (p - 1, pe, s, se));

  switch (xc)
    {
    case L('+'):                /* match one or more occurrences */
    case L('*'):                /* match zero or more occurrences */
      /* If we can get away with no matches, don't even bother.  Just
         call GMATCH on the rest of the pattern and return success if
         it succeeds. */
      if (xc == L('*') && (GMATCH (s, se, prest, pe, NULL, flags) == 0))
        return 0;

      /* OK, we have to do this the hard way.  First, we make sure one of
         the subpatterns matches, then we try to match the rest of the
         string. */
      for (psub = p + 1; ; psub = pnext)
        {
          pnext = PATSCAN (psub, pe, L('|'));
          for (srest = s; srest <= se; srest++)
            {
              /* Match this substring (S -> SREST) against this
                 subpattern (psub -> pnext - 1) */
              m1 = GMATCH (s, srest, psub, pnext - 1, NULL, flags) == 0;
              /* OK, we matched a subpattern, so make sure the rest of the
                 string matches the rest of the pattern.  Also handle
                 multiple matches of the pattern. */
              if (m1)
                {
                  /* if srest > s, we are not at start of string */
                  xflags = (srest > s) ? (flags & ~FNM_PERIOD) : flags;
                  m2 = (GMATCH (srest, se, prest, pe, NULL, xflags) == 0) ||
                        (s != srest && GMATCH (srest, se, p - 1, pe, NULL, xflags) == 0);
                }
              if (m1 && m2)
                return (0);
            }
          if (pnext == prest)
            break;
        }
      return (FNM_NOMATCH);

    case L('?'):                /* match zero or one of the patterns */
    case L('@'):                /* match one (or more) of the patterns */
      /* If we can get away with no matches, don't even bother.  Just
         call gmatch on the rest of the pattern and return success if
         it succeeds. */
      if (xc == L('?') && (GMATCH (s, se, prest, pe, NULL, flags) == 0))
        return 0;

      /* OK, we have to do this the hard way.  First, we see if one of
         the subpatterns matches, then, if it does, we try to match the
         rest of the string. */
      for (psub = p + 1; ; psub = pnext)
        {
          pnext = PATSCAN (psub, pe, L('|'));
          srest = (prest == pe) ? se : s;
          for ( ; srest <= se; srest++)
            {
              /* if srest > s, we are not at start of string */
              xflags = (srest > s) ? (flags & ~FNM_PERIOD) : flags;
              if (GMATCH (s, srest, psub, pnext - 1, NULL, flags) == 0 &&
                  GMATCH (srest, se, prest, pe, NULL, xflags) == 0)
                return (0);
            }
          if (pnext == prest)
            break;
        }
      return (FNM_NOMATCH);

    case '!':           /* match anything *except* one of the patterns */
      for (srest = s; srest <= se; srest++)
        {
          m1 = 0;
          for (psub = p + 1; ; psub = pnext)
            {
              pnext = PATSCAN (psub, pe, L('|'));
              /* If one of the patterns matches, just bail immediately. */
              if (m1 = (GMATCH (s, srest, psub, pnext - 1, NULL, flags) == 0))
                break;
              if (pnext == prest)
                break;
            }

          /* If nothing matched, but the string starts with a period and we
             need to match periods explicitly, don't return this as a match,
             even for negation. Might need to do this only if srest == s. */
          if (m1 == 0 && *s == '.' && (flags & FNM_PERIOD))
            return (FNM_NOMATCH);

          /* if srest > s, we are not at start of string */
          xflags = (srest > s) ? (flags & ~FNM_PERIOD) : flags;
          if (m1 == 0 && GMATCH (srest, se, prest, pe, NULL, xflags) == 0)
            return (0);
        }
      return (FNM_NOMATCH);
    }

  return (FNM_NOMATCH);
}
#endif /* EXTENDED_GLOB */

#undef IS_CCLASS
#undef FOLD
#undef CHAR
#undef U_CHAR
#undef XCHAR
#undef INT
#undef INVALID
#undef FCT
#undef GMATCH
#undef COLLSYM
#undef PARSE_COLLSYM
#undef PATSCAN
#undef STRCOMPARE
#undef EXTMATCH
#undef DEQUOTE_PATHNAME
#undef STRUCT
#undef BRACKMATCH
#undef STRCHR
#undef STRCOLL
#undef STRLEN
#undef STRCMP
#undef MEMCHR
#undef COLLEQUIV
#undef RANGECMP
#undef L