x_regex.c

一套客户/服务器模式的备份系统代码,跨平台,支持linux,AIX, IRIX, FreeBSD, Digital Unix (OSF1), Solaris and HP-UX.

		PATFETCH (c);

		/* \ might escape characters inside [...] and [^...].  */
		if ((syntax & RE_BACKSLASH_ESCAPE_IN_LISTS) && c == '\\')
		  {
		    if (p == pend) return REG_EESCAPE;

		    PATFETCH (c1);
		    SET_LIST_BIT (c1);
		    continue;
		  }

		/* Could be the end of the bracket expression.	If it's
		   not (i.e., when the bracket expression is `[]' so
		   far), the ']' character bit gets set way below.  */
		if (c == ']' && p != p1 + 1)
		  break;

		/* Look ahead to see if it's a range when the last thing
		   was a character class.  */
		if (had_char_class && c == '-' && *p != ']')
		  return REG_ERANGE;

		/* Look ahead to see if it's a range when the last thing
		   was a character: if this is a hyphen not at the
		   beginning or the end of a list, then it's the range
		   operator.  */
		if (c == '-' 
		    && !(p - 2 >= pattern && p[-2] == '[') 
		    && !(p - 3 >= pattern && p[-3] == '[' && p[-2] == '^')
		    && *p != ']')
		  {
		    reg_errcode_t ret
		      = compile_range (&p, pend, translate, syntax, b);
		    if (ret != REG_NOERROR) return ret;
		  }

		else if (p[0] == '-' && p[1] != ']')
		  { /* This handles ranges made up of characters only.	*/
		    reg_errcode_t ret;

		    /* Move past the `-'.  */
		    PATFETCH (c1);
		    
		    ret = compile_range (&p, pend, translate, syntax, b);
		    if (ret != REG_NOERROR) return ret;
		  }

		/* See if we're at the beginning of a possible character
		   class.  */

		else if (syntax & RE_CHAR_CLASSES && c == '[' && *p == ':')
		  { /* Leave room for the null.  */
		    UChar str[CHAR_CLASS_MAX_LENGTH + 1];

		    PATFETCH (c);
		    c1 = 0;

		    /* If pattern is `[[:'.  */
		    if (p == pend) return REG_EBRACK;

		    for (;;)
		      {
			PATFETCH (c);
			if (c == ':' || c == ']' || p == pend
			    || c1 == CHAR_CLASS_MAX_LENGTH)
			  break;
			str[c1++] = c;
		      }
		    str[c1] = '\0';

		    /* If isn't a word bracketed by `[:' and:`]':
		       undo the ending character, the letters, and leave 
		       the leading `:' and `[' (but set bits for them).  */
		    if (c == ':' && *p == ']')
		      {
			Int32 ch;
			boolean is_alnum = STREQ (str, "alnum");
			boolean is_alpha = STREQ (str, "alpha");
			boolean is_blank = STREQ (str, "blank");
			boolean is_cntrl = STREQ (str, "cntrl");
			boolean is_digit = STREQ (str, "digit");
			boolean is_graph = STREQ (str, "graph");
			boolean is_lower = STREQ (str, "lower");
			boolean is_print = STREQ (str, "print");
			boolean is_punct = STREQ (str, "punct");
			boolean is_space = STREQ (str, "space");
			boolean is_upper = STREQ (str, "upper");
			boolean is_xdigit = STREQ (str, "xdigit");
			
			if (!IS_CHAR_CLASS (str)) return REG_ECTYPE;

			/* Throw away the ] at the end of the character
			   class.  */
			PATFETCH (c);					

			if (p == pend) return REG_EBRACK;

			for (ch = 0; ch < 1 << BYTEWIDTH; ch++)
			  {
			    if (   (is_alnum  && ISALNUM (ch))
				|| (is_alpha  && ISALPHA (ch))
				|| (is_blank  && ISBLANK (ch))
				|| (is_cntrl  && ISCNTRL (ch))
				|| (is_digit  && ISDIGIT (ch))
				|| (is_graph  && ISGRAPH (ch))
				|| (is_lower  && ISLOWER (ch))
				|| (is_print  && ISPRINT (ch))
				|| (is_punct  && ISPUNCT (ch))
				|| (is_space  && ISASCSPACE (ch))
				|| (is_upper  && ISUPPER (ch))
				|| (is_xdigit && ISXDIGIT (ch)))
			    SET_LIST_BIT (ch);
			  }
			had_char_class = true;
		      }
		    else
		      {
			c1++;
			while (c1--)	
			  PATUNFETCH;
			SET_LIST_BIT ('[');
			SET_LIST_BIT (':');
			had_char_class = false;
		      }
		  }
		else
		  {
		    had_char_class = false;
		    SET_LIST_BIT (c);
		  }
	      }

	    /* Discard any (non)matching list bytes that are all 0 at the
	       end of the map.	Decrease the map-length byte too.  */
	    while ((Int32) b[-1] > 0 && b[b[-1] - 1] == 0) 
	      b[-1]--; 
	    b += b[-1];
	  }
	  break;


	case '(':
	  if (syntax & RE_NO_BK_PARENS)
	    goto handle_open;
	  else
	    goto normal_char;


	case ')':
	  if (syntax & RE_NO_BK_PARENS)
	    goto handle_close;
	  else
	    goto normal_char;


	case '\n':
	  if (syntax & RE_NEWLINE_ALT)
	    goto handle_alt;
	  else
	    goto normal_char;


	case '|':
	  if (syntax & RE_NO_BK_VBAR)
	    goto handle_alt;
	  else
	    goto normal_char;


	case '{':
	   if (syntax & RE_INTERVALS && syntax & RE_NO_BK_BRACES)
	     goto handle_interval;
	   else
	     goto normal_char;


	case '\\':
	  if (p == pend) return REG_EESCAPE;

	  /* Do not translate the character after the \, so that we can
	     distinguish, e.g., \B from \b, even if we normally would
	     translate, e.g., B to b.  */
	  PATFETCH_RAW (c);

	  switch (c)
	    {
	    case '(':
	      if (syntax & RE_NO_BK_PARENS)
		goto normal_backslash;

	    handle_open:
	      bufp->re_nsub++;
	      regnum++;

	      if (COMPILE_STACK_FULL)
		{ 
		  RETALLOC (compile_stack.stack, compile_stack.size << 1,
			    compile_stack_elt_t);
		  if (compile_stack.stack == NULL) return REG_ESPACE;

		  compile_stack.size <<= 1;
		}

	      /* These are the values to restore when we hit end of this
		 group.  They are all relative offsets, so that if the
		 whole pattern moves because of realloc, they will still
		 be valid.  */
	      COMPILE_STACK_TOP.begalt_offset = begalt - bufp->buffer;
	      COMPILE_STACK_TOP.fixup_alt_jump 
		= fixup_alt_jump ? fixup_alt_jump - bufp->buffer + 1 : 0;
	      COMPILE_STACK_TOP.laststart_offset = b - bufp->buffer;
	      COMPILE_STACK_TOP.regnum = regnum;

	      /* We will eventually replace the 0 with the number of
		 groups inner to this one.  But do not push a
		 start_memory for groups beyond the last one we can
		 represent in the compiled pattern.  */
	      if (regnum <= MAX_REGNUM)
		{
		  COMPILE_STACK_TOP.inner_group_offset = b - bufp->buffer + 2;
		  BUF_PUSH_3 (start_memory, regnum, 0);
		}
		
	      compile_stack.avail++;

	      fixup_alt_jump = 0;
	      laststart = 0;
	      begalt = b;
	      /* If we've reached MAX_REGNUM groups, then this open
		 won't actually generate any code, so we'll have to
		 clear pending_exact explicitly.  */
	      pending_exact = 0;
	      break;


	    case ')':
	      if (syntax & RE_NO_BK_PARENS) goto normal_backslash;

	      if (COMPILE_STACK_EMPTY){
		if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
		  goto normal_backslash;
		else
		  return REG_ERPAREN;
	      }

	    handle_close:
	      if (fixup_alt_jump)
		{ /* Push a dummy failure point at the end of the
		     alternative for a possible future
		     `pop_failure_jump' to pop.  See comments at
		     `push_dummy_failure' in `re_match_2'.  */
		  BUF_PUSH (push_dummy_failure);
		  
		  /* We allocated space for this jump when we assigned
		     to `fixup_alt_jump', in the `handle_alt' case below.  */
		  STORE_JUMP (jump_past_alt, fixup_alt_jump, b - 1);
		}

	      /* See similar code for backslashed left paren above.  */
	      if (COMPILE_STACK_EMPTY){
		if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
		  goto normal_char;
		else
		  return REG_ERPAREN;
	      }

	      /* Since we just checked for an empty stack above, this
		 ``can't happen''.  */
	      assert (compile_stack.avail != 0);
	      {
		/* We don't just want to restore into `regnum', because
		   later groups should continue to be numbered higher,
		   as in `(ab)c(de)' -- the second group is #2.  */
		regnum_t this_group_regnum;

		compile_stack.avail--;		
		begalt = bufp->buffer + COMPILE_STACK_TOP.begalt_offset;
		fixup_alt_jump
		  = COMPILE_STACK_TOP.fixup_alt_jump
		    ? bufp->buffer + COMPILE_STACK_TOP.fixup_alt_jump - 1 
		    : 0;
		laststart = bufp->buffer + COMPILE_STACK_TOP.laststart_offset;
		this_group_regnum = COMPILE_STACK_TOP.regnum;
		/* If we've reached MAX_REGNUM groups, then this open
		   won't actually generate any code, so we'll have to
		   clear pending_exact explicitly.  */
		pending_exact = 0;

		/* We're at the end of the group, so now we know how many
		   groups were inside this one.  */
		if (this_group_regnum <= MAX_REGNUM)
		  {
		    UChar *inner_group_loc
		      = bufp->buffer + COMPILE_STACK_TOP.inner_group_offset;
		    
		    *inner_group_loc = regnum - this_group_regnum;
		    BUF_PUSH_3 (stop_memory, this_group_regnum,
				regnum - this_group_regnum);
		  }
	      }
	      break;


	    case '|':					/* `\|'.  */
	      if (syntax & RE_LIMITED_OPS || syntax & RE_NO_BK_VBAR)
		goto normal_backslash;
	    handle_alt:
	      if (syntax & RE_LIMITED_OPS)
		goto normal_char;

	      /* Insert before the previous alternative a jump which
		 jumps to this alternative if the former fails.  */
	      GET_BUFFER_SPACE (3);
	      INSERT_JUMP (on_failure_jump, begalt, b + 6);
	      pending_exact = 0;
	      b += 3;

	      /* The alternative before this one has a jump after it
		 which gets executed if it gets matched.  Adjust that
		 jump so it will jump to this alternative's analogous
		 jump (put in below, which in turn will jump to the next
		 (if any) alternative's such jump, etc.).  The last such
		 jump jumps to the correct final destination.  A picture:
			  _____ _____ 
			  |   | |   |	
			  |   v |   v 
			 a | b	 | c   

		 If we are at `b', then fixup_alt_jump right now points to a
		 three-byte space after `a'.  We'll put in the jump, set
		 fixup_alt_jump to right after `b', and leave behind three
		 bytes which we'll fill in when we get to after `c'.  */

	      if (fixup_alt_jump)
		STORE_JUMP (jump_past_alt, fixup_alt_jump, b);

	      /* Mark and leave space for a jump after this alternative,
		 to be filled in later either by next alternative or
		 when know we're at the end of a series of alternatives.  */
	      fixup_alt_jump = b;
	      GET_BUFFER_SPACE (3);
	      b += 3;

	      laststart = 0;
	      begalt = b;
	      break;


	    case '{': 
	      /* If \{ is a literal.  */
	      if (!(syntax & RE_INTERVALS)
		     /* If we're at `\{' and it's not the open-interval 
			operator.  */
		  || ((syntax & RE_INTERVALS) && (syntax & RE_NO_BK_BRACES))
		  || (p - 2 == pattern	&&  p == pend))
		goto normal_backslash;

	    handle_interval:
	      {
		/* If got here, then the syntax allows intervals.  */

		/* At least (most) this many matches must be made.  */
		Int32 lower_bound = -1, upper_bound = -1;

		beg_interval = p - 1;

		if (p == pend)
		  {
		    if (syntax & RE_NO_BK_BRACES)
		      goto unfetch_interval;
		    else
		      return REG_EBRACE;
		  }

		GET_UNSIGNED_NUMBER (lower_bound);

		if (c == ',')
		  {
		    GET_UNSIGNED_NUMBER (upper_bound);
		    if (upper_bound < 0) upper_bound = RE_DUP_MAX;
		  }
		else
		  /* Interval such as `{1}' => match exactly once. */
		  upper_bound = lower_bound;

		if (lower_bound < 0 || upper_bound > RE_DUP_MAX
		    || lower_bound > upper_bound)
		  {
		    if (syntax & RE_NO_BK_BRACES)
		      goto unfetch_interval;
		    else 
		      return REG_BADBR;
		  }

		if (!(syntax & RE_NO_BK_BRACES)) 
		  {
		    if (c != '\\') return REG_EBRACE;

		    PATFETCH (c);
		  }

		if (c != '}')
		  {
		    if (syntax & RE_NO_BK_BRACES)
		      goto unfetch_interval;
		    else 
		      return REG_BADBR;
		  }

		/* We just parsed a valid interval.  */

		/* If it's invalid to have no preceding re.  */
		if (!laststart)
		  {
		    if (syntax & RE_CONTEXT_INVALID_OPS)
		      return REG_BADRPT;
		    else if (syntax & RE_CONTEXT_INDEP_OPS)
		      laststart = b;
		    else
		      goto unfetch_interval;
		  }

		/* If the upper bound is zero, don't want to succeed at
		   all; jump from `laststart' to `b + 3', which will be
		   the end of the buffer after we insert the jump.  */
		 if (upper_bound == 0)
		   {
		     GET_BUFFER_SPACE (3);
		     INSERT_JUMP (jump, laststart, b + 3);
		     b += 3;
		   }

		 /* Otherwise, we have a nontrivial interval.  When
		    we're all done, the pattern will look like:
		      set_number_at <jump count> <upper bound>
		      set_number_at <succeed_n count> <lower bound>
		      succeed_n <after jump addr> <succed_n count>
		      <body of loop>
		      jump_n <succeed_n addr> <jump count>
		    (The upper bound and `jump_n' are omitted if
		    `upper_bound' is 1, though.)  */
		 else 
		   { /* If the upper bound is > 1, we need to insert
			more at the end of the loop.  */
		     Uns32 nbytes = 10 + (upper_bound > 1) * 10;

		     GET_BUFFER_SPACE (nbytes);

		     /* Initialize lower bound of the `succeed_n', even
			though it will be set during matching by its
			attendant `set_number_at' (inserted next),
			because `re_compile_fastmap' needs to know.
			Jump to the `jump_n' we might insert below.  */
		     INSERT_JUMP2 (succeed_n, laststart,
				   b + 5 + (upper_bound > 1) * 5,
				   lower_bound);
		     b += 5;

		     /* Code to initialize the lower bound.  Insert 
			before the `succeed_n'.  The `5' is the last two
			bytes of this `set_number_at', plus 3 bytes of
			the following `succeed_n'.  */
		     insert_op2 (set_number_at, laststart,
					(Int32) 5, lower_bound, b);
		     b += 5;

		     if (upper_bound > 1)
		       { /* More than one repetition is allowed, so
			    append a backward jump to the `succeed_n'
			    that starts this interval.
			    
			    When we've reached this during matching,
			    we'll have matched the interval once, so
			    jump back only `upper_bound - 1' times.  */
			 STORE_JUMP2 (jump_n, b, laststart + 5,
				      upper_bound - 1);