Patch-ID: bash40-030

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

/* Copyright (C) 1991-2006 Free Software Foundation, Inc.

   This file is part of GNU Bash, the Bourne Again SHell.
   
   Bash 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.

   Bash 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 Bash.  If not, see <http://www.gnu.org/licenses/>.
*/

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

static int GMATCH __P((CHAR *, CHAR *, CHAR *, CHAR *, int));
static CHAR *PARSE_COLLSYM __P((CHAR *, INT *));
static CHAR *BRACKMATCH __P((CHAR *, U_CHAR, int));
static int EXTMATCH __P((INT, CHAR *, CHAR *, CHAR *, CHAR *, int));
static CHAR *PATSCAN __P((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, flags));
}

/* Match STRING against the filename pattern PATTERN, returning zero if
   it matches, FNM_NOMATCH if not.  */
static int
GMATCH (string, se, pattern, pe, flags)
     CHAR *string, *se;
     CHAR *pattern, *pe;
     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)
            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 '*':               /* Match zero or more characters */
          if (p == pe)
            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;

          /* 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;
                  for (newn = n; newn < se; ++newn)
                    {
                      if (EXTMATCH (c, newn, se, p, pe, flags) == 0)
                        return (0);
                    }
                  /* We didn't match.  If we have a `?(...)', that's failure. */
                  return FNM_NOMATCH;
                }
#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;
            }

          /* 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);

          /* General case, use recursion. */
          {
            U_CHAR c1;

            c1 = ((flags & FNM_NOESCAPE) == 0 && c == L('\\')) ? *p : c;
            c1 = FOLD (c1);
            for (--p; n < se; ++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, flags & ~FNM_PERIOD) == 0)
                  return (0);
              }
            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;
   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;
  INT pc;
  CHAR *savep;

  test = FOLD (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;

      /* 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');
                  pc = IS_CCLASS (test, (XCHAR *)ccname);
                }
              if (pc == -1)
                pc = 0;
              else
                p = close + 2;

              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;
        }

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

      cstart = cend = FOLD (cstart);

      /* 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 ((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;
            }
          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) > 0)
            {
              if (c == L(']'))
                break;
              c = FOLD (c);
              continue;
            }
        }

      if (RANGECMP (test, cstart) >= 0 && RANGECMP (test, cend) <= 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;
  while (brcnt > 0)
    {
      /* A `[' without a matching `]' is just another character to match. */
      if (c == L('\0'))
        return ((test == L('[')) ? savep : (CHAR *)0);

      c = *p++;
      if (c == L('[') && (*p == L('=') || *p == L(':') || *p == L('.')))
        brcnt++;
      else if (c == L(']'))
        brcnt--;
      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. */
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;

  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;

  c1 = *pe;
  c2 = *se;

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

  *pe = c1;
  *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, 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, 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, xflags) == 0) ||
                        (s != srest && GMATCH (srest, se, p - 1, pe, 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, 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, flags) == 0 &&
                  GMATCH (srest, se, prest, pe, 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, flags) == 0))
                break;
              if (pnext == prest)
                break;
            }
          /* 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, 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 BRACKMATCH
#undef STRCHR
#undef STRCOLL
#undef STRLEN
#undef STRCMP
#undef COLLEQUIV
#undef RANGECMP
#undef L