[bpt/emacs.git] / lisp / progmodes / cc-engine.el

;;; cc-engine.el --- core syntax guessing engine for CC mode

;; Copyright (C) 1985,87,92,93,94,95,96,97,98 Free Software Foundation, Inc.

;; Authors:    1998 Barry A. Warsaw and Martin Stjernholm
;;             1992-1997 Barry A. Warsaw
;;             1987 Dave Detlefs and Stewart Clamen
;;             1985 Richard M. Stallman
;; Maintainer: bug-cc-mode@gnu.org
;; Created:    22-Apr-1997 (split from cc-mode.el)
;; Version:    See cc-mode.el
;; Keywords:   c languages oop

;; This file is part of GNU Emacs.

;; GNU Emacs 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 2, or (at your option)
;; any later version.

;; GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

\f
(eval-when-compile
  (require 'cc-defs))

;; KLUDGE ALERT: c-maybe-labelp is used to pass information between
;; c-crosses-statement-barrier-p and c-beginning-of-statement-1.  A
;; better way should be implemented, but this will at least shut up
;; the byte compiler.
(defvar c-maybe-labelp nil)

;; WARNING WARNING WARNING
;;
;; Be *exceptionally* careful about modifications to this function!
;; Much of CC Mode depends on this Doing The Right Thing.  If you
;; break it you will be sorry.  If you think you know how this works,
;; you probably don't.  No human on Earth does! :-)
;;
;; WARNING WARNING WARNING

(defun c-beginning-of-statement-1 (&optional lim)
  ;; move to the start of the current statement, or the previous
  ;; statement if already at the beginning of one.
  (let ((firstp t)
	(substmt-p t)
	donep c-in-literal-cache saved
	(last-begin (point)))
    ;; first check for bare semicolon
    (if (and (progn (c-backward-syntactic-ws lim)
		    (eq (char-before) ?\;))
	     (c-safe (progn (forward-char -1)
			    (setq saved (point))
			    t))
	     (progn (c-backward-syntactic-ws lim)
		    (memq (char-before) '(?\; ?{ ?:)))
	     )
	(setq last-begin saved)
      (goto-char last-begin)
      (while (not donep)
	;; stop at beginning of buffer
	(if (bobp) (setq donep t)
	  ;; go backwards one balanced expression, but be careful of
	  ;; unbalanced paren being reached
	  (if (not (c-safe (progn (c-backward-sexp 1) t)))
	      (progn
		(if firstp
		    (backward-up-list 1)
		  (goto-char last-begin))
		;; skip over any unary operators, or other special
		;; characters appearing at front of identifier
		(save-excursion
		  (c-backward-syntactic-ws lim)
		  (skip-chars-backward "-+!*&:.~@ \t\n")
		  (if (eq (char-before) ?\()
		      (setq last-begin (point))))
		(goto-char last-begin)
		(setq last-begin (point)
		      donep t)))

	  (setq c-maybe-labelp nil)
	  ;; see if we're in a literal. if not, then this bufpos may be
	  ;; a candidate for stopping
	  (cond
	   ;; CASE 0: did we hit the error condition above?
	   (donep)
	   ;; CASE 1: are we in a literal?
	   ((eq (c-in-literal lim) 'pound)
	    (beginning-of-line))
	   ;; CASE 2: some other kind of literal?
	   ((c-in-literal lim))
	   ;; CASE 3: are we looking at a conditional keyword?
	   ((or (looking-at c-conditional-key)
		(and (eq (char-after) ?\()
		     (save-excursion
		       (c-forward-sexp 1)
		       (c-forward-syntactic-ws)
		       (not (eq (char-after) ?\;)))
		     (let ((here (point))
			   (foundp (progn
				     (c-backward-syntactic-ws lim)
				     (forward-word -1)
				     (and lim
					  (<= lim (point))
					  (not (c-in-literal lim))
					  (not (eq (char-before) ?_))
					  (looking-at c-conditional-key)
					  ))))
		       ;; did we find a conditional?
		       (if (not foundp)
			   (goto-char here))
		       foundp)))
	    ;; are we in the middle of an else-if clause?
	    (if (save-excursion
		  (and (not substmt-p)
		       (c-safe (progn (c-forward-sexp -1) t))
		       (looking-at "\\<else\\>[ \t\n]+\\<if\\>")
		       (not (c-in-literal lim))))
		(progn
		  (c-forward-sexp -1)
		  (c-backward-to-start-of-if lim)))
	    ;; are we sitting at an else clause, that we are not a
	    ;; substatement of?
	    (if (and (not substmt-p)
		     (looking-at "\\<else\\>[^_]"))
		(c-backward-to-start-of-if lim))
	    ;; a finally or a series of catches?
	    (if (not substmt-p)
		(while (looking-at "\\<\\(catch\\|finally\\)\\>[^_]")
		  (c-safe (c-backward-sexp 2))
		  (if (eq (char-after) ?\()
		      (c-safe (c-backward-sexp)))))
	    ;; are we sitting at the while of a do-while?
	    (if (and (looking-at "\\<while\\>[^_]")
		     (c-backward-to-start-of-do lim))
		(setq substmt-p nil))
	    (setq last-begin (point)
		  donep substmt-p))
	   ;; CASE 4: are we looking at a label?
	   ((looking-at c-label-key))
	   ;; CASE 5: is this the first time we're checking?
	   (firstp (setq firstp nil
			 substmt-p (not (c-crosses-statement-barrier-p
					 (point) last-begin))
			 last-begin (point)))
	   ;; CASE 6: have we crossed a statement barrier?
	   ((save-excursion
	      ;; Move over in-expression blocks before checking the
	      ;; barrier
	      (if (or (memq (char-after) '(?\( ?\[))
		      (and (eq (char-after) ?{)
			   (c-looking-at-inexpr-block lim)))
		  (c-forward-sexp 1))
	      (c-crosses-statement-barrier-p (point) last-begin))
	    (setq donep t))
	   ;; CASE 7: ignore labels
	   ((and c-maybe-labelp
		 (or (and c-access-key (looking-at c-access-key))
		     ;; with switch labels, we have to go back further
		     ;; to try to pick up the case or default
		     ;; keyword. Potential bogosity alert: we assume
		     ;; `case' or `default' is first thing on line
		     (let ((here (point)))
		       (beginning-of-line)
		       (c-forward-syntactic-ws)
		       (if (looking-at c-switch-label-key)
			   t
			 (goto-char here)
			 nil))
		     (looking-at c-label-key))))
	   ;; CASE 8: ObjC or Java method def
	   ((and c-method-key
		 (setq last-begin (c-in-method-def-p)))
	    (setq donep t))
	   ;; CASE 9: nothing special
	   (t (setq last-begin (point)))
	   ))))
    (goto-char last-begin)
    ;; We always want to skip over the non-whitespace modifier
    ;; characters that can start a statement.
    (let ((lim (point)))
      (skip-chars-backward "-+!*&~@ \t\n" (c-point 'boi))
      (skip-chars-forward " \t\n" lim))))

(defun c-end-of-statement-1 ()
  (condition-case nil
      (let (beg end found)
	(while (and (not (eobp))
		    (progn
		      (setq beg (point))
		      (c-forward-sexp 1)
		      (setq end (point))
		      (goto-char beg)
		      (setq found nil)
		      (while (and (not found)
				  (re-search-forward "[;{}]" end t))
			(if (not (c-in-literal beg))
			    (setq found t)))
		      (not found)))
	  (goto-char end))
	(re-search-backward "[;{}]")
	(forward-char 1))
    (error
     (let ((beg (point)))
       (c-safe (backward-up-list -1))
       (let ((end (point)))
	 (goto-char beg)
	 (search-forward ";" end 'move)))
     )))

\f
(defun c-crosses-statement-barrier-p (from to)
  ;; Does buffer positions FROM to TO cross a C statement boundary?
  (let ((here (point))
	(lim from)
	crossedp)
    (condition-case ()
	(progn
	  (goto-char from)
	  (while (and (not crossedp)
		      (< (point) to))
	    (skip-chars-forward "^;{}:" (1- to))
	    (if (not (c-in-literal lim))
		(progn
		  (if (memq (char-after) '(?\; ?{ ?}))
		      (setq crossedp t)
		    (if (eq (char-after) ?:)
			(setq c-maybe-labelp t))
		    (forward-char 1))
		  (setq lim (point)))
	      (forward-char 1))))
      (error (setq crossedp nil)))
    (goto-char here)
    crossedp))

\f
;; Skipping of "syntactic whitespace", defined as lexical whitespace,
;; C and C++ style comments, and preprocessor directives.  Search no
;; farther back or forward than optional LIM.  If LIM is omitted,
;; `beginning-of-defun' is used for backward skipping, point-max is
;; used for forward skipping.

(defun c-forward-syntactic-ws (&optional lim)
  ;; Forward skip of syntactic whitespace for Emacs 19.
  (let* ((here (point-max))
	 (hugenum (point-max)))
    (while (/= here (point))
      (setq here (point))
      (forward-comment hugenum)
      ;; skip preprocessor directives
      (when (and (eq (char-after) ?#)
		 (= (c-point 'boi) (point)))
	(while (eq (char-before (c-point 'eol)) ?\\)
	  (forward-line 1))
	(end-of-line))
      )
    (if lim (goto-char (min (point) lim)))))

(defsubst c-beginning-of-macro (&optional lim)
  ;; Go to the beginning of a cpp macro definition.  Leaves point at
  ;; the beginning of the macro and returns t if in a cpp macro
  ;; definition, otherwise returns nil and leaves point unchanged.
  ;; `lim' is currently ignored, but the interface requires it.
  (let ((here (point)))
    (beginning-of-line)
    (while (eq (char-before (1- (point))) ?\\)
      (forward-line -1))
    (back-to-indentation)
    (if (eq (char-after) ?#)
	t
      (goto-char here)
      nil)))

(defun c-backward-syntactic-ws (&optional lim)
  ;; Backward skip over syntactic whitespace for Emacs 19.
  (let* ((here (point-min))
	 (hugenum (- (point-max))))
    (while (/= here (point))
      (setq here (point))
      (forward-comment hugenum)
      (c-beginning-of-macro))
    (if lim (goto-char (max (point) lim)))))

\f
;; Moving by tokens, where a token is defined as all symbols and
;; identifiers which aren't syntactic whitespace (note that "->" is
;; considered to be two tokens).  Point is always either left at the
;; beginning of a token or not moved at all.  COUNT specifies the
;; number of tokens to move; a negative COUNT moves in the opposite
;; direction.  A COUNT of 0 moves to the next token beginning only if
;; not already at one.  If BALANCED is true, move over balanced
;; parens, otherwise move into them.  Also, if BALANCED is true, never
;; move out of an enclosing paren.  LIM sets the limit for the
;; movement and defaults to the point limit.  Returns the number of
;; tokens left to move (positive or negative).  If BALANCED is true, a
;; move over a balanced paren counts as one.  Note that if COUNT is 0
;; and no appropriate token beginning is found, 1 will be returned.
;; Thus, a return value of 0 guarantees that point is at the requested
;; position and a return value less (without signs) than COUNT
;; guarantees that point is at the beginning of some token.

(defun c-forward-token-1 (&optional count balanced lim)
  (or count (setq count 1))
  (if (< count 0)
      (- (c-backward-token-1 (- count) balanced lim))
    (let ((jump-syntax (if balanced
			   '(?w ?_ ?\( ?\) ?\" ?\\ ?/ ?$ ?')
			 '(?w ?_ ?\" ?\\ ?/ ?')))
	  (last (point))
	  (prev (point)))
      (if (/= (point)
	      (progn (c-forward-syntactic-ws) (point)))
	  ;; Skip whitespace.  Count this as a move if we did in fact
	  ;; move and aren't out of bounds.
	  (or (eobp)
	      (and lim (> (point) lim))
	      (setq count (max (1- count) 0))))
      (if (and (= count 0)
	       (or (and (memq (char-syntax (or (char-after) ? )) '(?w ?_))
			(memq (char-syntax (or (char-before) ? )) '(?w ?_)))
		   (eobp)))
	  ;; If count is zero we should jump if in the middle of a
	  ;; token or if there is whitespace between point and the
	  ;; following token beginning.
	  (setq count 1))
      ;; Avoid having the limit tests inside the loop.
      (save-restriction
	(if lim (narrow-to-region (point-min) lim))
	(if (eobp)
	    (goto-char last)
	  (condition-case nil
	      (while (> count 0)
		(setq prev last
		      last (point))
		(if (memq (char-syntax (char-after)) jump-syntax)
		    (goto-char (scan-sexps (point) 1))
		  (forward-char))
		(c-forward-syntactic-ws lim)
		(setq count (1- count)))
	    (error (goto-char last)))
	  (when (eobp)
	    (goto-char prev)
	    (setq count (1+ count)))))
      count)))

(defun c-backward-token-1 (&optional count balanced lim)
  (or count (setq count 1))
  (if (< count 0)
      (- (c-forward-token-1 (- count) balanced lim))
    (let ((jump-syntax (if balanced
			   '(?w ?_ ?\( ?\) ?\" ?\\ ?/ ?$ ?')
			 '(?w ?_ ?\" ?\\ ?/ ?')))
	  last)
      (if (and (= count 0)
	       (or (and (memq (char-syntax (or (char-after) ? )) '(?w ?_))
			(memq (char-syntax (or (char-before) ? )) '(?w ?_)))
		   (/= (point)
		       (save-excursion (c-forward-syntactic-ws) (point)))
		   (eobp)))
	  ;; If count is zero we should jump if in the middle of a
	  ;; token or if there is whitespace between point and the
	  ;; following token beginning.
	  (setq count 1))
      ;; Avoid having the limit tests inside the loop.
      (save-restriction
	(if lim (narrow-to-region lim (point-max)))
	(or (bobp)
	    (progn
	      (condition-case nil
		  (while (progn
			   (setq last (point))
			   (> count 0))
		    (c-backward-syntactic-ws lim)
		    (if (memq (char-syntax (char-before)) jump-syntax)
			(goto-char (scan-sexps (point) -1))
		      (backward-char))
		    (setq count (1- count)))
		(error (goto-char last)))
	      (if (bobp) (goto-char last)))))
      count)))

\f
;; Return `c' if in a C-style comment, `c++' if in a C++ style
;; comment, `string' if in a string literal, `pound' if on a
;; preprocessor line, or nil if not in a comment at all.  Optional LIM
;; is used as the backward limit of the search.  If omitted, or nil,
;; `beginning-of-defun' is used."

(defun c-in-literal (&optional lim)
  ;; Determine if point is in a C++ literal. we cache the last point
  ;; calculated if the cache is enabled
  (if (and (boundp 'c-in-literal-cache)
	   c-in-literal-cache
	   (= (point) (aref c-in-literal-cache 0)))
      (aref c-in-literal-cache 1)
    (let ((rtn (save-excursion
		 (let* ((lim (or lim (c-point 'bod)))
			(state (parse-partial-sexp lim (point))))
		   (cond
		    ((nth 3 state) 'string)
		    ((nth 4 state) (if (nth 7 state) 'c++ 'c))
		    ((c-beginning-of-macro lim) 'pound)
		    (t nil))))))
      ;; cache this result if the cache is enabled
      (and (boundp 'c-in-literal-cache)
	   (setq c-in-literal-cache (vector (point) rtn)))
      rtn)))

;; XEmacs has a built-in function that should make this much quicker.
;; I don't think we even need the cache, which makes our lives more
;; complicated anyway.  In this case, lim is ignored.
(defun c-fast-in-literal (&optional lim)
  (let ((context (buffer-syntactic-context)))
    (cond
     ((eq context 'string) 'string)
     ((eq context 'comment) 'c++)
     ((eq context 'block-comment) 'c)
     ((save-excursion (c-beginning-of-macro lim)) 'pound))))

(if (fboundp 'buffer-syntactic-context)
    (defalias 'c-in-literal 'c-fast-in-literal))

(defun c-literal-limits (&optional lim near)
  ;; Returns a cons of the beginning and end positions of the comment
  ;; or string surrounding point (including both delimiters), or nil
  ;; if point isn't in one.  If LIM is non-nil, it's used as the
  ;; "safe" position to start parsing from.  If NEAR is non-nil, then
  ;; the limits of any literal next to point is returned.  "Next to"
  ;; means there's only [ \t] between point and the literal.  The
  ;; search for such a literal is done first in forward direction.
  ;;
  ;; This is the Emacs 19 version.
  (save-excursion
    (let* ((pos (point))
	   (lim (or lim (c-point 'bod)))
	   (state (parse-partial-sexp lim (point))))
      (cond ((nth 3 state)
	     ;; String.  Search backward for the start.
	     (while (nth 3 state)
	       (search-backward (make-string 1 (nth 3 state)))
	       (setq state (parse-partial-sexp lim (point))))
	     (cons (point) (or (c-safe (c-forward-sexp 1) (point))
			       (point-max))))
	    ((nth 7 state)
	     ;; Line comment.  Search from bol for the comment starter.
	     (beginning-of-line)
	     (setq state (parse-partial-sexp lim (point))
		   lim (point))
	     (while (not (nth 7 state))
	       (search-forward "//")	; Should never fail.
	       (setq state (parse-partial-sexp
			    lim (point) nil nil state)
		     lim (point)))
	     (backward-char 2)
	     (cons (point) (progn (forward-comment 1) (point))))
	    ((nth 4 state)
	     ;; Block comment.  Search backward for the comment starter.
	     (while (nth 4 state)
	       (search-backward "/*")	; Should never fail.
	       (setq state (parse-partial-sexp lim (point))))
	     (cons (point) (progn (forward-comment 1) (point))))
	    ((c-safe (nth 4 (parse-partial-sexp ; Can't use prev state due
			     lim (1+ (point))))) ; to bug in Emacs 19.34.
	     ;; We're standing in a comment starter.
	     (backward-char 2)
	     (cons (point) (progn (forward-comment 1) (point))))
	    (near
	     (goto-char pos)
	     ;; Search forward for a literal.
	     (skip-chars-forward " \t")
	     (cond
	      ((eq (char-syntax (or (char-after) ?\ )) ?\") ; String.
	       (cons (point) (or (c-safe (c-forward-sexp 1) (point))
				 (point-max))))
	      ((looking-at "/[/*]")	; Line or block comment.
	       (cons (point) (progn (forward-comment 1) (point))))
	      (t
	       ;; Search backward.
	       (skip-chars-backward " \t")
	       (let ((end (point)) beg)
		 (cond
		  ((eq (char-syntax (or (char-before) ?\ )) ?\") ; String.
		   (setq beg (c-safe (c-backward-sexp 1) (point))))
		  ((and (c-safe (forward-char -2) t)
			(looking-at "*/"))
		   ;; Block comment.  Due to the nature of line
		   ;; comments, they will always be covered by the
		   ;; normal case above.
		   (goto-char end)
		   (forward-comment -1)
		   ;; If LIM is bogus, beg will be bogus.
		   (setq beg (point))))
		 (if beg (cons beg end))))))
	    ))))

(defun c-literal-limits-fast (&optional lim)
  ;; Like c-literal-limits, but for emacsen whose `parse-partial-sexp'
  ;; returns the pos of the comment start.  FIXME: Add NEAR.
  (save-excursion
    (let ((state (parse-partial-sexp lim (point))))
      (cond ((nth 3 state)		; String.
	     (goto-char (nth 8 state))
	     (cons (point) (or (c-safe (c-forward-sexp 1) (point))
			       (point-max))))
	    ((nth 4 state)		; Comment.
	     (goto-char (nth 8 state))
	     (cons (point) (progn (forward-comment 1) (point))))
	    ((c-safe
	      (nth 4 (parse-partial-sexp ; Works?
		      (point) (1+ (point)) nil nil state)))
	     ;; We're in a comment starter.
	     (backward-char 2)
	     (cons (point) (progn (forward-comment 1) (point))))
	    ))))

(defun c-collect-line-comments (range)
  ;; If the argument is a cons of two buffer positions (such as
  ;; returned by c-literal-limits), and that range contains a C++
  ;; style line comment, then an extended range is returned that
  ;; contains all adjacent line comments (i.e. all comments that
  ;; starts in the same column with no empty lines or non-whitespace
  ;; characters between them).  Otherwise the argument is returned.
  (save-excursion
    (condition-case nil
	(if (and (consp range) (progn
				 (goto-char (car range))
				 (looking-at "//")))
	    (let ((col (current-column))
		  (beg (point))
		  (end (cdr range)))
	      (while (and (not (bobp))
			  (forward-comment -1)
			  (looking-at "//")
			  (= col (current-column)))
		(setq beg (point)))
	      (goto-char end)
	      (while (progn
		       (skip-chars-forward " \t")
		       (and (looking-at "//")
			    (= col (current-column))))
		(forward-comment 1)
		(setq end (point)))
	      (cons beg end))
	  range)
      (error range))))

(defun c-literal-type (range)
  ;; Convenience function that given the result of c-literal-limits,
  ;; returns nil or the type of literal that the range surrounds.
  ;; It's much faster than using c-in-literal and is intended to be
  ;; used when you need both the type of a literal and its limits.
  (if (consp range)
    (save-excursion
      (goto-char (car range))
      (cond ((eq (char-syntax (or (char-after) ?\ )) ?\") 'string)
	    ((looking-at "//") 'c++)
	    (t 'c)))			; Assuming the range is valid.
    range))


\f
;; utilities for moving and querying around syntactic elements
(defvar c-parsing-error nil)

(defun c-parse-state ()
  ;; Finds and records all open parens between some important point
  ;; earlier in the file and point.
  ;;
  ;; if there's a state cache, return it
  (setq c-parsing-error nil)
  (if (boundp 'c-state-cache) c-state-cache
    (let* (at-bob
	   (pos (save-excursion
		  ;; go back 2 bods, but ignore any bogus positions
		  ;; returned by beginning-of-defun (i.e. open paren
		  ;; in column zero)
		  (let ((cnt 2))
		    (while (not (or at-bob (zerop cnt)))
		      (goto-char (c-point 'bod))
		      (if (and
			   (eq (char-after) ?\{)
			   ;; The following catches an obscure special
			   ;; case where the brace is preceded by an
			   ;; open paren.  That can only legally occur
			   ;; with blocks inside expressions and in
			   ;; Pike special brace lists.  Even so, this
			   ;; test is still bogus then, but hopefully
			   ;; good enough.  (We don't want to use
			   ;; up-list here since it might be slow.)
			   (save-excursion
			     (c-backward-syntactic-ws)
			     (not (eq (char-before) ?\())))
			  (setq cnt (1- cnt)))
		      (if (bobp)
			  (setq at-bob t))))
		  (point)))
	   (here (save-excursion
		   ;;(skip-chars-forward " \t}")
		   (point)))
	   (last-bod pos) (last-pos pos)
	   placeholder state sexp-end)
      ;; cache last bod position
      (while (catch 'backup-bod
	       (setq state nil)
	       (while (and pos (< pos here))
		 (setq last-pos pos)
		 (if (and (setq pos (c-safe (scan-lists pos 1 -1)))
			  (<= pos here))
		     (progn
		       (setq sexp-end (c-safe (scan-sexps (1- pos) 1)))
		       (if (and sexp-end
				(<= sexp-end here))
			   ;; we want to record both the start and end
			   ;; of this sexp, but we only want to record
			   ;; the last-most of any of them before here
			   (progn
			     (if (eq (char-after (1- pos)) ?\{)
				 (setq state (cons (cons (1- pos) sexp-end)
						   (if (consp (car state))
						       (cdr state)
						     state))))
			     (setq pos sexp-end))
			 ;; we're contained in this sexp so put pos on
			 ;; front of list
			 (setq state (cons (1- pos) state))))
		   ;; something bad happened. check to see if we
		   ;; crossed an unbalanced close brace. if so, we
		   ;; didn't really find the right `important bufpos'
		   ;; so lets back up and try again
		   (if (and (not pos) (not at-bob)
			    (setq placeholder
				  (c-safe (scan-lists last-pos 1 1)))
			    ;;(char-after (1- placeholder))
			    (<= placeholder here)
			    (eq (char-after (1- placeholder)) ?\}))
		       (while t
			 (setq last-bod (c-safe (scan-lists last-bod -1 1)))
			 (if (not last-bod)
			     (progn
			       ;; bogus, but what can we do here?
			       (setq c-parsing-error (1- placeholder))
			       (throw 'backup-bod nil))
			   (setq at-bob (= last-bod (point-min))
				 pos last-bod)
			   (if (= (char-after last-bod) ?\{)
			       (throw 'backup-bod t)))
			 ))		;end-if
		   ))			;end-while
	       nil))
      state)))

(defun c-whack-state (bufpos state)
  ;; whack off any state information that appears on STATE which lies
  ;; after the bounds of BUFPOS.
  (let (newstate car)
    (while state
      (setq car (car state)
	    state (cdr state))
      (if (consp car)
	  ;; just check the car, because in a balanced brace
	  ;; expression, it must be impossible for the corresponding
	  ;; close brace to be before point, but the open brace to be
	  ;; after.
	  (if (<= bufpos (car car))
	      nil			; whack it off
	    ;; its possible that the open brace is before bufpos, but
	    ;; the close brace is after.  In that case, convert this
	    ;; to a non-cons element.
	    (if (<= bufpos (cdr car))
		(setq newstate (append newstate (list (car car))))
	      ;; we know that both the open and close braces are
	      ;; before bufpos, so we also know that everything else
	      ;; on state is before bufpos, so we can glom up the
	      ;; whole thing and exit.
	      (setq newstate (append newstate (list car) state)
		    state nil)))
	(if (<= bufpos car)
	    nil				; whack it off
	  ;; it's before bufpos, so everything else should too
	  (setq newstate (append newstate (list car) state)
		state nil))))
    newstate))

(defun c-hack-state (bufpos which state)
  ;; Using BUFPOS buffer position, and WHICH (must be 'open or
  ;; 'close), hack the c-parse-state STATE and return the results.
  (if (eq which 'open)
      (let ((car (car state)))
	(if (or (null car)
		(consp car)
		(/= bufpos car))
	    (cons bufpos state)
	  state))
    (if (not (eq which 'close))
	(error "c-hack-state, bad argument: %s" which))
    ;; 'close brace
    (let ((car (car state))
	  (cdr (cdr state)))
      (if (consp car)
	  (setq car (car cdr)
		cdr (cdr cdr)))
      ;; TBD: is this test relevant???
      (if (consp car)
	  state				;on error, don't change
	;; watch out for balanced expr already on cdr of list
	(cons (cons car bufpos)
	      (if (consp (car cdr))
		  (cdr cdr) cdr))
	))))

(defun c-adjust-state (from to shift state)
  ;; Adjust all points in state that lie in the region FROM..TO by
  ;; SHIFT amount.
  (mapcar
   (function
    (lambda (e)
      (if (consp e)
	  (let ((car (car e))
		(cdr (cdr e)))
	    (if (and (<= from car) (< car to))
		(setcar e (+ shift car)))
	    (if (and (<= from cdr) (< cdr to))
		(setcdr e (+ shift cdr))))
	(if (and (<= from e) (< e to))
	    (setq e (+ shift e))))
      e))
   state))

\f
(defun c-beginning-of-inheritance-list (&optional lim)
  ;; Go to the first non-whitespace after the colon that starts a
  ;; multiple inheritance introduction.  Optional LIM is the farthest
  ;; back we should search.
  (let ((lim (or lim (c-point 'bod)))
	(placeholder (progn
		       (back-to-indentation)
		       (point))))
    (c-backward-syntactic-ws lim)
    (while (and (> (point) lim)
		(memq (char-before) '(?, ?:))
		(progn
		  (beginning-of-line)
		  (setq placeholder (point))
		  (skip-chars-forward " \t")
		  (not (looking-at c-class-key))
		  ))
      (c-backward-syntactic-ws lim))
    (goto-char placeholder)
    (skip-chars-forward "^:" (c-point 'eol))))

(defun c-in-method-def-p ()
  ;; Return nil if we aren't in a method definition, otherwise the
  ;; position of the initial [+-].
  (save-excursion
    (beginning-of-line)
    (and c-method-key
	 (looking-at c-method-key)
	 (point))
    ))

(defun c-at-toplevel-p ()
  "Return a determination as to whether point is at the `top-level'.
Being at the top-level means that point is either outside any
enclosing block (such function definition), or inside a class
definition, but outside any method blocks.

If point is not at the top-level (e.g. it is inside a method
definition), then nil is returned.  Otherwise, if point is at a
top-level not enclosed within a class definition, t is returned.
Otherwise, a 2-vector is returned where the zeroth element is the
buffer position of the start of the class declaration, and the first
element is the buffer position of the enclosing class's opening
brace."
  (let ((state (c-parse-state)))
    (or (not (c-most-enclosing-brace state))
	(c-search-uplist-for-classkey state))))

(defun c-just-after-func-arglist-p (&optional containing)
  ;; Return t if we are between a function's argument list closing
  ;; paren and its opening brace.  Note that the list close brace
  ;; could be followed by a "const" specifier or a member init hanging
  ;; colon.  Optional CONTAINING is position of containing s-exp open
  ;; brace.  If not supplied, point is used as search start.
  (save-excursion
    (c-backward-syntactic-ws)
    (let ((checkpoint (or containing (point))))
      (goto-char checkpoint)
      ;; could be looking at const specifier
      (if (and (eq (char-before) ?t)
	       (forward-word -1)
	       (looking-at "\\<const\\>"))
	  (c-backward-syntactic-ws)
	;; otherwise, we could be looking at a hanging member init
	;; colon
	(goto-char checkpoint)
	(if (and (eq (char-before) ?:)
		 (progn
		   (forward-char -1)
		   (c-backward-syntactic-ws)
		   (looking-at "[ \t\n]*:\\([^:]+\\|$\\)")))
	    nil
	  (goto-char checkpoint))
	)
      (and (eq (char-before) ?\))
	   ;; check if we are looking at a method def
	   (or (not c-method-key)
	       (progn
		 (c-forward-sexp -1)
		 (forward-char -1)
		 (c-backward-syntactic-ws)
		 (not (or (memq (char-before) '(?- ?+))
			  ;; or a class category
			  (progn
			    (c-forward-sexp -2)
			    (looking-at c-class-key))
			  )))))
      )))

;; defuns to look backwards for things
(defun c-backward-to-start-of-do (&optional lim)
  ;; Move to the start of the last "unbalanced" do expression.
  ;; Optional LIM is the farthest back to search.  If none is found,
  ;; nil is returned and point is left unchanged, otherwise t is returned.
  (let ((do-level 1)
	(case-fold-search nil)
	(lim (or lim (c-point 'bod)))
	(here (point))
	foundp)
    (while (not (zerop do-level))
      ;; we protect this call because trying to execute this when the
      ;; while is not associated with a do will throw an error
      (condition-case nil
	  (progn
	    (c-backward-sexp 1)
	    (cond
	     ;; break infloop for illegal C code
	     ((bobp) (setq do-level 0))
	     ((memq (c-in-literal lim) '(c c++)))
	     ((looking-at "while\\b[^_]")
	      (setq do-level (1+ do-level)))
	     ((looking-at "do\\b[^_]")
	      (if (zerop (setq do-level (1- do-level)))
		  (setq foundp t)))
	     ((<= (point) lim)
	      (setq do-level 0)
	      (goto-char lim))))
	(error
	 (goto-char lim)
	 (setq do-level 0))))
    (if (not foundp)
	(goto-char here))
    foundp))

(defun c-backward-to-start-of-if (&optional lim)
  ;; Move to the start of the last "unbalanced" if and return t.  If
  ;; none is found, and we are looking at an if clause, nil is
  ;; returned.  If none is found and we are looking at an else clause,
  ;; an error is thrown.
  (let ((if-level 1)
	(here (c-point 'bol))
	(case-fold-search nil)
	(lim (or (and (>= (point) lim)
		      lim)
		 (c-point 'bod)))
	(at-if (looking-at "if\\b[^_]")))
    (catch 'orphan-if
      (while (and (not (bobp))
		  (not (zerop if-level)))
	(c-backward-syntactic-ws)
	(condition-case nil
	    (c-backward-sexp 1)
	  (error
	   (if at-if
	       (throw 'orphan-if nil)
	     (error "No matching `if' found for `else' on line %d."
		    (1+ (count-lines 1 here))))))
	(cond
	 ((looking-at "else\\b[^_]")
	  (setq if-level (1+ if-level)))
	 ((looking-at "if\\b[^_]")
	  ;; check for else if... skip over
	  (let ((here (point)))
	    (c-safe (c-forward-sexp -1))
	    (if (looking-at "\\<else\\>[ \t]+\\<if\\>")
		nil
	      (setq if-level (1- if-level))
	      (goto-char here))))
	 ((< (point) lim)
	  (setq if-level 0)
	  (goto-char lim))
	 ))
      t)))

(defun c-skip-conditional ()
  ;; skip forward over conditional at point, including any predicate
  ;; statements in parentheses. No error checking is performed.
  (c-forward-sexp (cond
		   ;; else if()
		   ((looking-at "\\<else\\>[ \t]+\\<if\\>") 3)
		   ;; do, else, try, finally
		   ((looking-at "\\<\\(do\\|else\\|try\\|finally\\)\\>") 1)
		   ;; for, if, while, switch, catch, synchronized
		   (t 2))))

(defun c-skip-case-statement-forward (state &optional lim)
  ;; skip forward over case/default bodies, with optional maximal
  ;; limit. if no next case body is found, nil is returned and point
  ;; is not moved
  (let ((lim (or lim (point-max)))
	(here (point))
	donep foundp bufpos
	(safepos (point))
	(balanced (car state)))
    ;; search until we've passed the limit, or we've found our match
    (while (and (< (point) lim)
		(not donep))
      (setq safepos (point))
      ;; see if we can find a case statement, not in a literal
      (if (and (re-search-forward c-switch-label-key lim 'move)
	       (setq bufpos (match-beginning 0))
	       (not (c-in-literal safepos))
	       (/= bufpos here))
	  ;; if we crossed into a balanced sexp, we know the case is
	  ;; not part of our switch statement, so just bound over the
	  ;; sexp and keep looking.
	  (if (and (consp balanced)
		   (> bufpos (car balanced))
		   (< bufpos (cdr balanced)))
	      (goto-char (cdr balanced))
	    (goto-char bufpos)
	    (setq donep t
		  foundp t))))
    (if (not foundp)
	(goto-char here))
    foundp))

(defun c-search-uplist-for-classkey (brace-state)
  ;; search for the containing class, returning a 2 element vector if
  ;; found. aref 0 contains the bufpos of the boi of the class key
  ;; line, and aref 1 contains the bufpos of the open brace.
  (if (null brace-state)
      ;; no brace-state means we cannot be inside a class
      nil
    (let ((carcache (car brace-state))
	  search-start search-end)
      (if (consp carcache)
	  ;; a cons cell in the first element means that there is some
	  ;; balanced sexp before the current bufpos. this we can
	  ;; ignore. the nth 1 and nth 2 elements define for us the
	  ;; search boundaries
	  (setq search-start (nth 2 brace-state)
		search-end (nth 1 brace-state))
	;; if the car was not a cons cell then nth 0 and nth 1 define
	;; for us the search boundaries
	(setq search-start (nth 1 brace-state)
	      search-end (nth 0 brace-state)))
      ;; search-end cannot be a cons cell
      (and (consp search-end)
	   (error "consp search-end: %s" search-end))
      ;; if search-end is nil, or if the search-end character isn't an
      ;; open brace, we are definitely not in a class
      (if (or (not search-end)
	      (< search-end (point-min))
	      (not (eq (char-after search-end) ?{)))
	  nil
	;; now, we need to look more closely at search-start.  if
	;; search-start is nil, then our start boundary is really
	;; point-min.
	(if (not search-start)
	    (setq search-start (point-min))
	  ;; if search-start is a cons cell, then we can start
	  ;; searching from the end of the balanced sexp just ahead of
	  ;; us
	  (if (consp search-start)
	      (setq search-start (cdr search-start))))
	;; now we can do a quick regexp search from search-start to
	;; search-end and see if we can find a class key.  watch for
	;; class like strings in literals
	(save-excursion
	  (save-restriction
	    (goto-char search-start)
	    (let ((search-key (concat c-class-key "\\|" c-extra-toplevel-key))
		  foundp class match-end)
	      (if c-inexpr-class-key
		  (setq search-key (concat search-key "\\|"
					   c-inexpr-class-key)))
	      (while (and (not foundp)
			  (progn
			    (c-forward-syntactic-ws)
			    (> search-end (point)))
			  (re-search-forward search-key search-end t))
		(setq class (match-beginning 0)
		      match-end (match-end 0))
		(if (c-in-literal search-start)
		    nil			; its in a comment or string, ignore
		  (goto-char class)
		  (skip-chars-forward " \t\n")
		  (setq foundp (vector (c-point 'boi) search-end))
		  (cond
		   ;; check for embedded keywords
		   ((let ((char (char-after (1- class))))
		      (and char
			   (memq (char-syntax char) '(?w ?_))))
		    (goto-char match-end)
		    (setq foundp nil))
		   ;; make sure we're really looking at the start of a
		   ;; class definition, and not a forward decl, return
		   ;; arg, template arg list, or an ObjC or Java method.
		   ((and c-method-key
			 (re-search-forward c-method-key search-end t)
			 (not (c-in-literal class)))
		    (setq foundp nil))
		   ;; Check if this is an anonymous inner class.
		   ((and c-inexpr-class-key
			 (looking-at c-inexpr-class-key))
		    (while (and (= (c-forward-token-1 1 t) 0)
				(looking-at "(\\|\\w\\|\\s_\\|\\.")))
		    (if (eq (point) search-end)
			;; We're done.  Just trap this case in the cond.
			nil
		      ;; False alarm; all conditions aren't satisfied.
		      (setq foundp nil)))
		   ;; Its impossible to define a regexp for this, and
		   ;; nearly so to do it programmatically.
		   ;;
		   ;; ; picks up forward decls
		   ;; = picks up init lists
		   ;; ) picks up return types
		   ;; > picks up templates, but remember that we can
		   ;;   inherit from templates!
		   ((let ((skipchars "^;=)"))
		      ;; try to see if we found the `class' keyword
		      ;; inside a template arg list
		      (save-excursion
			(skip-chars-backward "^<>" search-start)
			(if (eq (char-before) ?<)
			    (setq skipchars (concat skipchars ">"))))
		      (while (progn
			       (skip-chars-forward skipchars search-end)
			       (c-in-literal class))
			(forward-char))
		      (/= (point) search-end))
		    (setq foundp nil))
		   )))
	      foundp))
	  )))))

(defun c-inside-bracelist-p (containing-sexp brace-state)
  ;; return the buffer position of the beginning of the brace list
  ;; statement if we're inside a brace list, otherwise return nil.
  ;; CONTAINING-SEXP is the buffer pos of the innermost containing
  ;; paren. BRACE-STATE is the remainder of the state of enclosing braces
  ;;
  ;; N.B.: This algorithm can potentially get confused by cpp macros
  ;; places in inconvenient locations.  Its a trade-off we make for
  ;; speed.
  (or
   ;; this will pick up enum lists
   (c-safe
    (save-excursion
      (goto-char containing-sexp)
      (c-forward-sexp -1)
      (let (bracepos)
	(if (and (or (looking-at "enum[\t\n ]+")
		     (progn (c-forward-sexp -1)
			    (looking-at "enum[\t\n ]+")))
		 (setq bracepos (c-safe (scan-lists (point) 1 -1)))
		 (not (c-crosses-statement-barrier-p (point)
						     (- bracepos 2))))
	    (point)))))
   ;; this will pick up array/aggregate init lists, even if they are nested.
   (save-excursion
     (let ((class-key
	    ;; Pike can have class definitions anywhere, so we must
	    ;; check for the class key here.
	    (and (c-major-mode-is 'pike-mode)
		 (concat c-class-key "\\|" c-extra-toplevel-key)))
	   bufpos lim braceassignp)
       (while (and (not bufpos)
		   containing-sexp)
	 (if (consp containing-sexp)
	     (setq containing-sexp (car brace-state)
		   brace-state (cdr brace-state))
	   (goto-char containing-sexp)
	   (if (c-looking-at-inexpr-block)
	       ;; We're in an in-expression block of some kind.  Do
	       ;; not check nesting.
	       (setq containing-sexp nil)
	     ;; see if the open brace is preceded by = or [...] in
	     ;; this statement, but watch out for operator=
	     (setq lim (if (consp (car brace-state))
			   (cdr (car brace-state))
			 (car brace-state))
		   braceassignp 'dontknow)
	     (while (and (eq braceassignp 'dontknow)
			 (zerop (c-backward-token-1 1 t lim)))
	       (cond ((eq (char-after) ?\;)
		      (setq braceassignp nil))
		     ((and class-key
			   (looking-at class-key))
		      (setq braceassignp nil))
		     ((eq (char-after) ?=)
		      ;; We've seen a =, but must check earlier tokens so
		      ;; that it isn't something that should be ignored.
		      (setq braceassignp 'maybe)
		      (while (and (eq braceassignp 'maybe)
				  (zerop (c-backward-token-1 1 t lim)))
			(setq braceassignp
			      (cond
			       ;; Check for operator =
			       ((looking-at "operator\\>") nil)
			       ;; Check for `<opchar>= (Pike)
			       ((eq (char-after) ?`) nil)
			       ((looking-at "\\s.") 'maybe)
			       ;; make sure we're not in a C++ template
			       ;; argument assignment
			       ((save-excursion
				  (let ((here (point))
					(pos< (progn
						(skip-chars-backward "^<")
						(point))))
				    (and (c-major-mode-is 'c++-mode)
					 (eq (char-before) ?<)
					 (not (c-crosses-statement-barrier-p
					       here pos<))
					 (not (c-in-literal))
					 )))
				nil)
			       (t t)))))
		     ((eq (char-after) ?\[)
		      ;; In Java, an initialization brace list may
		      ;; follow "new Foo[]", so check for [].  Got to
		      ;; watch out for the C++ "operator[]" defun,
		      ;; though.
		      (setq braceassignp
			    (save-excursion
			      (c-backward-token-1)
			      (not (looking-at "operator\\>")))))
		     ))
	     (if (memq braceassignp '(nil dontknow))
		 (if (eq (char-after) ?\;)
		     ;; Brace lists can't contain a semicolon, so we're done.
		     (setq containing-sexp nil)
		   ;; lets see if we're nested. find the most nested
		   ;; containing brace
		   (setq containing-sexp (car brace-state)
			 brace-state (cdr brace-state)))
	       ;; we've hit the beginning of the aggregate list
	       (c-beginning-of-statement-1
		(c-most-enclosing-brace brace-state))
	       (setq bufpos (point))))
	   ))
       bufpos))
   ))

(defun c-looking-at-special-brace-list (&optional lim)