/* Tags file maker to go with GNUmacs
   Copyright (C) 1984 Richard M. Stallman and Ken Arnold

This program is distributed in the hope that it will be useful,
but without any warranty.  No author or distributor
accepts responsibility to anyone for the consequences of using it
or for whether it serves any particular purpose or works at all,
unless he says so in writing.

   Permission is granted to anyone to distribute verbatim copies
   of this program's source code as received, in any medium, provided that
   the copyright notice, the nonwarraty notice above
   and this permission notice are preserved,
   and that the distributor grants the recipient all rights
   for further redistribution as permitted by this notice,
   and informs him of these rights.

   Permission is granted to distribute modified versions of this
   program's source code, or of portions of it, under the above
   conditions, plus the conditions that all changed files carry
   prominent notices stating who last changed them and that the
   derived material, including anything packaged together with it and
   conceptually functioning as a modification of it rather than an
   application of it, is in its entirety subject to a permission
   notice identical to this one.

   Permission is granted to distribute this program (verbatim or
   as modified) in compiled or executable form, provided verbatim
   redistribution is permitted as stated above for source code, and
    A.  it is accompanied by the corresponding machine-readable
      source code, under the above conditions, or
    B.  it is accompanied by a written offer, with no time limit,
      to distribute the corresponding machine-readable source code,
      under the above conditions, to any one, in return for reimbursement
      of the cost of distribution.   Verbatim redistribution of the
      written offer must be permitted.  Or,
    C.  it is distributed by someone who received only the
      compiled or executable form, and is accompanied by a copy of the
      written offer of source code which he received along with it.

   Permission is granted to distribute this program (verbatim or as modified)
   in executable form as part of a larger system provided that the source
   code for this program, including any modifications used,
   is also distributed or offered as stated in the preceding paragraph.

In other words, you are welcome to use, share and improve this program.
You are forbidden to forbid anyone else to use, share and improve
what you give them.   Help stamp out software-hoarding!  */

#include <stdio.h>
#include <ctype.h>

/* Define the symbol ETAGS to make the program "etags",
 which makes emacs-style tag tables by default.
 Define CTAGS to make the program "ctags" compatible with the usual one.
 Default is ETAGS.  */

#ifndef CTAGS
#define ETAGS 1
#endif

#define	reg	register
#define	logical	char

#define	TRUE	(1)
#define	FALSE	(0)

#define	iswhite(arg)	(_wht[arg])	/* T if char is white		*/
#define	begtoken(arg)	(_btk[arg])	/* T if char can start token	*/
#define	intoken(arg)	(_itk[arg])	/* T if char can be in token	*/
#define	endtoken(arg)	(_etk[arg])	/* T if char ends tokens	*/
#define	isgood(arg)	(_gd[arg])	/* T if char can be after ')'	*/

#define	max(I1,I2)	(I1 > I2 ? I1 : I2)

struct	nd_st {			/* sorting structure			*/
	char	*entry;			/* function or type name	*/
	char	*file;			/* file name			*/
	logical f;			/* use pattern or line no	*/
	int	lno;			/* line number tag is on	*/
	long    cno;			/* character number line starts on */
	char	*pat;			/* search pattern		*/
	logical	been_warned;		/* set if noticed dup		*/
	struct	nd_st	*left,*right;	/* left and right sons		*/
};

long	ftell();
typedef	struct	nd_st	NODE;

int number; /* tokens found so far on line starting with # (including #) */
logical gotone,				/* found a func already on line	*/
					/* boolean "func" (see init)	*/
	_wht[0177],_etk[0177],_itk[0177],_btk[0177],_gd[0177];

	/* typedefs are recognized using a simple finite automata,
	 * tydef is its state variable.
	 */
typedef enum {none, begin, middle, end } TYST;

TYST tydef = none;

char	searchar = '/';			/* use /.../ searches 		*/

int	lineno;			/* line number of current line */
long	charno;			/* current character number */
long	linecharno;		/* character number of start of line */

char    *curfile,		/* current input file name		*/
	*outfile= "tags",	/* output file				*/
	*white	= " \f\t\n",	/* white chars				*/
	*endtk	= " \t\n\"'#()[]{}=-+%*/&|^~!<>;,.:?",
				/* token ending chars			*/
	*begtk	= "ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz",
				/* token starting chars			*/
	*intk	= "ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz0123456789",
				/* valid in-token chars			*/
	*notgd	= ",;";		/* non-valid after-function chars	*/

int	file_num;		/* current file number			*/
int	aflag;			/* -a: append to tags */
int	tflag;			/* -t: create tags for typedefs */
int	uflag;			/* -u: update tags */
int	wflag;			/* -w: suppress warnings */
int	vflag;			/* -v: create vgrind style index output */
int	xflag;			/* -x: create cxref style output */
int	eflag;			/* -e: emacs style output */

FILE	*inf,			/* ioptr for current input file		*/
	*outf;			/* ioptr for tags file			*/

NODE	*head;			/* the head of the sorted binary tree	*/

char	*savestr();
char	*rindex();
char *concat ();
void initbuffer ();
long readline ();

/* A `struct linebuffer' is a structure which holds a line of text.
 `readline' reads a line from a stream into a linebuffer
 and works regardless of the length of the line.  */

struct linebuffer
  {
    long size;
    char *buffer;
  };

struct linebuffer lb, lb1;

main(ac,av)
     int	ac;
     char	*av[];
{
  char cmd[100];
  int i;

#ifdef ETAGS
  eflag = 1;
#endif

  while (ac > 1 && av[1][0] == '-')
    {
      eflag = 0;
      for (i=1; av[1][i]; i++)
	{
	  switch(av[1][i])
	    {
	    case 'B':
	      searchar='?';
	      break;
	    case 'F':
	      searchar='/';
	      break;
	    case 'a':
	      aflag++;
	      break;
	    case 'e':
	      eflag++;
	      break;
	    case 't':
	      tflag++;
	      break;
	    case 'u':
	      uflag++;
	      break;
	    case 'w':
	      wflag++;
	      break;
	    case 'v':
	      vflag++;
	      xflag++;
	      break;
	    case 'x':
	      xflag++;
	      break;
	    default:
	      goto usage;
	    }
	}
      ac--; av++;
    }

  if (ac <= 1)
    {
    usage:
      printf("Usage: ctags [-BFaetuwvx] file ...\n");
      exit(1);
    }

  if (eflag)
    outfile = "TAGS";

  init();			/* set up boolean "functions"		*/

  initbuffer (&lb);
  initbuffer (&lb1);
  /*
   * loop through files finding functions
   */
  if (eflag)
    {
      outf = fopen (outfile, aflag ? "a" : "w");
      if (!outf)
	{
	  perror (outfile);
	  exit (1);
	}
    }

  for (file_num = 1; file_num < ac; file_num++)
    {
      find_entries(av[file_num]);
      if (eflag)
	{
	  fprintf (outf, "\f\n%s,%d\n",
		   av[file_num], total_size_of_entries (head));
	  put_entries (head);
	  free_tree (head);
	  head = NULL;
	}
    }

  if (eflag)
    {
      fclose (outf);
      exit (0);
    }

  if (xflag)
    {
      put_entries(head);
      exit(0);
    }
  if (uflag)
    {
      for (i=1; i<ac; i++)
	{
	  sprintf(cmd,
		  "mv %s OTAGS;fgrep -v '\t%s\t' OTAGS >%s;rm OTAGS",
		  outfile, av[i], outfile);
	  system(cmd);
	}
      aflag++;
    }
  outf = fopen(outfile, aflag ? "a" : "w");
  if (outf == NULL)
    {
      perror(outfile);
      exit(1);
    }
  put_entries(head);
  fclose(outf);
  if (uflag)
    {
      sprintf(cmd, "sort %s -o %s", outfile, outfile);
      system(cmd);
    }
  exit(0);
}

/*
 * This routine sets up the boolean psuedo-functions which work
 * by seting boolean flags dependent upon the corresponding character
 * Every char which is NOT in that string is not a white char.  Therefore,
 * all of the array "_wht" is set to FALSE, and then the elements
 * subscripted by the chars in "white" are set to TRUE.  Thus "_wht"
 * of a char is TRUE if it is the string "white", else FALSE.
 */
init()
{

  reg char *sp;
  reg int i;

  for (i = 0; i < 0177; i++)
    {
      _wht[i] = _etk[i] = _itk[i] = _btk[i] = FALSE;
      _gd[i] = TRUE;
    }
  for (sp = white; *sp; sp++)
    _wht[*sp] = TRUE;
  for (sp = endtk; *sp; sp++)
    _etk[*sp] = TRUE;
  for (sp = intk; *sp; sp++)
    _itk[*sp] = TRUE;
  for (sp = begtk; *sp; sp++)
    _btk[*sp] = TRUE;
  for (sp = notgd; *sp; sp++)
    _gd[*sp] = FALSE;
  _wht[0] = _wht['\n'];
  _etk[0] = _etk['\n'];
  _btk[0] = _btk['\n'];
  _itk[0] = _itk['\n'];
  _gd[0] = _gd['\n'];
}

/*
 * This routine opens the specified file and calls the function
 * which finds the function and type definitions.
 */
find_entries (file)
     char *file;
{
  char *cp;

  if ((inf=fopen(file,"r")) == NULL)
    {
      perror(file);
      return;
    }
  curfile = savestr(file);
  cp = rindex(file, '.');
  /* .l or .el or .lisp implies lisp source code */
  if (cp && (!strcmp (cp + 1, "l") || !strcmp (cp + 1, "el")
	     || !strcmp (cp + 1, "lisp")))
    {
      L_funcs(inf);
      fclose(inf);
      return;
    }
  /* if not a .c or .h or .y file, try fortran */
  if (cp && (cp[1] != 'c' && cp[1] != 'h' && cp[1] != 'y')
      && cp[2] == '\0')
    {
      if (PF_funcs(inf) != 0)
	{
	  fclose(inf);
	  return;
	}
      rewind(inf);	/* no fortran tags found, try C */
    }
  C_entries();
  fclose(inf);
}

/* Record a tag on the current line.
  name is the tag name,
  f is nonzero to use a pattern, zero to use line number instead. */

pfnote (name, f, linestart, linelen, lno, cno)
     char *name;
     logical f;			/* f == TRUE when function */
     char *linestart;
     int linelen;
     int lno;
     long cno;
{
  register char *fp;
  register NODE *np;
  char *altname;
  char tem[51];

  if ((np = (NODE *) malloc(sizeof (NODE))) == NULL)
    {
      fprintf(stderr, "ctags: too many entries to sort\n");
      put_entries(head);
      free_tree(head);
      head = NULL;
      np = (NODE *) xmalloc(sizeof (NODE));
    }
  /* Change name "main" to M<thisfilename>. */
  if (!eflag && !xflag && !strcmp(name, "main"))
    {
      fp = rindex(curfile, '/');
      if (fp == 0)
	fp = curfile;
      else
	fp++;
      altname = concat ("M", fp, "");
      fp = rindex(altname, '.');
      if (fp && fp[2] == 0)
	*fp = 0;
      name = altname;
    }
  np->entry = savestr(name);
  np->file = curfile;
  np->f = f;
  np->lno = lno;
  np->cno = cno;
  np->left = np->right = 0;
  if (eflag)
    {
      linestart[linelen] = 0;
    }
  else if (xflag == 0)
    {
      sprintf (tem, strlen (linestart) < 50 ? "%s$" : "%.50s", linestart);
      linestart = tem;
    }
  np->pat = savestr (linestart);
  if (head == NULL)
    head = np;
  else
    add_node(np, head);
}

free_tree(node)
     NODE *node;
{
  while (node)
    {
      free_tree(node->right);
      free(node);
      node = node->left;
    }
}

add_node(node, cur_node)
     NODE *node,*cur_node;
{
  register int dif;

  dif = strcmp(node->entry, cur_node->entry);

  /* If this tag name matches an existing one, then
     unless -e was given, do not add the node, but maybe print a warning */
  if (!eflag && !dif)
    {
      if (node->file == cur_node->file)
	{
	  if (!wflag)
	    {
	      fprintf(stderr,"Duplicate entry in file %s, line %d: %s\n",
		      node->file,lineno,node->entry);
	      fprintf(stderr,"Second entry ignored\n");
	    }
	  return;
	}
      if (!cur_node->been_warned)
	if (!wflag)
	  fprintf(stderr,"Duplicate entry in files %s and %s: %s (Warning only)\n",
		  node->file, cur_node->file, node->entry);
      cur_node->been_warned = TRUE;
      return;
    } 

  /* Actually add the node */
  if (dif < 0) 
    {
      if (cur_node->left != NULL)
	add_node(node,cur_node->left);
      else
	cur_node->left = node;
      return;
    }
  if (cur_node->right != NULL)
    add_node(node,cur_node->right);
  else
    cur_node->right = node;
}

put_entries(node)
     reg NODE *node;
{
  reg char *sp;

  if (node == NULL)
    return;

  /* Output subentries that precede this one */
  put_entries (node->left);

  /* Output this entry */

  if (eflag)
    {
      fprintf (outf, "%s%c%d,%d\n",
	       node->pat, 0177, node->lno, node->cno);
    }
  else if (!xflag)
    {
      fprintf (outf, "%s\t%s\t",
	       node->entry, node->file);

      if (node->f)
	{		/* a function */
	  putc (searchar, outf);
	  putc ('^', outf);

	  for (sp = node->pat; *sp; sp++)
	    {
	      if (*sp == '\\' || *sp == searchar)
		putc ('\\', outf);
	      putc (*sp, outf);
	    }
	  putc (searchar, outf);
	}
      else
	{		/* a typedef; text pattern inadequate */
	  fprintf (outf, "%d", node->lno);
	}
      putc ('\n', outf);
    }
  else if (vflag)
    fprintf (stdout, "%s %s %d\n",
	     node->entry, node->file, (node->lno+63)/64);
  else
    fprintf (stdout, "%-16s%4d %-16s %s\n",
	     node->entry, node->lno, node->file, node->pat);

  /* Output subentries that follow this one */
  put_entries (node->right);
}

/* Return total number of characters that put_entries will output for
 the nodes in the subtree of the specified node.
 Works only if eflag is set, but called only in that case.  */

total_size_of_entries(node)
     reg NODE *node;
{
  reg int total = 0;
  reg long num;

  if (node == NULL)
    return 0;

  /* Count subentries that precede this one */
  total = total_size_of_entries (node->left);

  /* Count subentries that follow this one */
  total += total_size_of_entries (node->right);

  /* Count this entry */

  total += strlen (node->pat) + 3;

  num = node->lno;
  while (num)
    {
      total++;
      num /= 10;
    }

  num = node->cno;
  if (!num) total++;
  while (num)
    {
      total++;
      num /= 10;
    }
  return total;
}

/*
 * This routine finds functions and typedefs in C syntax and adds them
 * to the list.
 */
#define CNL_SAVE_NUMBER \
{ \
  linecharno = charno; lineno++; \
  charno += 1 + readline (&lb, inf); \
  lp = lb.buffer; \
}

#define CNL \
{ \
  CNL_SAVE_NUMBER; \
  number = 0; \
}

C_entries ()
{
  register int c;
  register char *token, *tp, *lp;
  logical incomm, inquote, inchar, midtoken;
  int level;
  char tok[BUFSIZ];

  lineno = 0;
  charno = 0;
  lp = lb.buffer;
  *lp = 0;

  number = 0;
  gotone = midtoken = inquote = inchar = incomm = FALSE;
  level = 0;

  while (!feof (inf))
    {
      c = *lp++;
      if (c == 0)
	{
	  CNL;
	  gotone = FALSE;
	}
      if (c == '\\')
	{
	  c = *lp++;
	  if (c == 0)
	    CNL_SAVE_NUMBER;
	  c = ' ';
	} 
      else if (incomm)
	{
	  if (c == '*')
	    {
	      while ((c = *lp++) == '*')
		continue;
	      if (c == 0)
		CNL;
	      if (c == '/')
		incomm = FALSE;
	    }
	}
      else if (inquote)
	{
	  /*
	  * Too dumb to know about \" not being magic, but
	  * they usually occur in pairs anyway.
	  */
	  if (c == '"')
	    inquote = FALSE;
	  continue;
	}
      else if (inchar)
	{
	  if (c == '\'')
	    inchar = FALSE;
	  continue;
	}
      else switch (c)
	{
	case '"':
	  inquote = TRUE;
	  continue;
	case '\'':
	  inchar = TRUE;
	  continue;
	case '/':
	  if (*lp == '*')
	    {
	      lp++;
	      incomm = TRUE;
	    }
	  continue;
	case '#':
	  if (lp == lb.buffer + 1)
	    number = 1;
	  continue;
	case '{':
	  if (tydef == begin)
	    {
	      tydef=middle;
	    }
	  level++;
	  continue;
	case '}':
	  if (lp == lb.buffer + 1)
	    level = 0;	/* reset */
	  else
	    level--;
	  if (!level && tydef==middle)
	    {
	      tydef=end;
	    }
	  continue;
	}
      if (!level && !inquote && !incomm && gotone == FALSE)
	{
	  if (midtoken)
	    {
	      if (endtoken(c))
		{
		  int f;
		  char *buf = lb.buffer;
		  int endpos = lp - lb.buffer;
		  char *lp1 = lp;
		  int line = lineno;
		  long linestart = linecharno;
		  int tem = consider_token (&lp1, token, &f);
		  lp = lp1;
		  if (tem)
		    {
		      if (linestart != linecharno)
			{
			  getline (linestart);
			  strncpy (tok, token + (lb1.buffer - buf),
				   tp-token+1);
			  tok[tp-token+1] = 0;
			  pfnote(tok, f, lb1.buffer, endpos, line, linestart);
			}
		      else
			{
			  strncpy (tok, token, tp-token+1);
			  tok[tp-token+1] = 0;
			  pfnote(tok, f, lb.buffer, endpos, line, linestart);
			}
		      gotone = f;	/* function */
		    }
		  midtoken = FALSE;
		  token = lp - 1;
		}
	      else if (intoken(c))
		tp++;
	    }
	  else if (begtoken(c))
	    {
	      token = tp = lp - 1;
	      midtoken = TRUE;
	    }
	}
      if (c == ';'  &&  tydef==end)	/* clean with typedefs */
	tydef=none;
    }
}

/*
 * This routine  checks to see if the current token is
 * at the start of a function, or corresponds to a typedef
 * It updates the input line * so that the '(' will be
 * in it when it returns.
 */
consider_token (lpp, token, f)
     char **lpp, *token;
     int *f;
{
  reg char *lp = *lpp;
  reg char c;
  static logical next_token_is_func;
  logical firsttok;	/* T if have seen first token in ()'s */
  int bad, win;

  *f = 1;			/* a function */
  c = lp[-1];
  bad = FALSE;
  if (!number)
    {		/* space is not allowed in macro defs	*/
      while (iswhite(c))
	{
	  c = *lp++;
	  if (c == 0)
	    {
	      if (feof (inf))
		break;
	      CNL;
	    }
	}
      /* the following tries to make it so that a #define a b(c)	*/
      /* doesn't count as a define of b.				*/
    }
  else
    {
      number++;
      if (number >= 4  || (number==2 && strncmp (token, "define", 6)))
	{
	  gotone = TRUE;
	badone:
	  bad = TRUE;
	  goto ret;
	}
    }
  /* check for the typedef cases		*/
  if (tflag && !strncmp(token, "typedef", 7))
    {
      tydef=begin;
      goto badone;
    }
  if (tydef==begin && (!strncmp(token, "struct", 6) ||
		       !strncmp(token, "union", 5) || !strncmp(token, "enum", 4)))
  {
    goto badone;
  }
  if (tydef==begin)
    {
      tydef=end;
      goto badone;
    }
  if (tydef==end)
    {
      *f = 0;
      win = 1;
      goto ret;
    }
  /* Detect GNUmacs's function-defining macros. */
  if (!number && !strncmp (token, "DEF", 3))
	 
    {
      next_token_is_func = 1;
      goto badone;
    }
  if (next_token_is_func)
    {
      next_token_is_func = 0;
      win = 1;
      goto ret;
    }
  if (c != '(')
    goto badone;
  firsttok = FALSE;
  while ((c = *lp++) != ')')
    {
      if (c == 0)
	{
	  if (feof (inf))
	    break;
	  CNL;
	}
      /*
	* This line used to confuse ctags:
	*	int	(*oldhup)();
	* This fixes it. A nonwhite char before the first
	* token, other than a / (in case of a comment in there)
	* makes this not a declaration.
	*/
      if (begtoken(c) || c=='/') firsttok++;
      else if (!iswhite(c) && !firsttok) goto badone;
    }
  while (iswhite (c = *lp++))
    {
      if (!c)
	CNL;
    }
  win = isgood (c);
ret:
  *lpp = lp - 1;
  return !bad && win;
}

getline (atchar)
     long atchar;
{
  long saveftell = ftell (inf);

  fseek (inf, atchar, 0);
  readline (&lb1, inf);
  fseek (inf, saveftell, 0);
}

/* Fortran parsing */

char	*dbp;
int	pfcnt;

PF_funcs(fi)
     FILE *fi;
{
  lineno = 0;
  charno = 0;
  pfcnt = 0;

  while (!feof (fi))
    {
      lineno++;
      linecharno = charno;
      charno += readline (&lb, fi) + 1;
      dbp = lb.buffer;
      if (*dbp == '%') dbp++ ;	/* Ratfor escape to fortran */
      while (isspace(*dbp))
	dbp++;
      if (*dbp == 0)
	continue;
      switch (*dbp |' ')
	{
	case 'i':
	  if (tail("integer"))
	    takeprec();
	  break;
	case 'r':
	  if (tail("real"))
	    takeprec();
	  break;
	case 'l':
	  if (tail("logical"))
	    takeprec();
	  break;
	case 'c':
	  if (tail("complex") || tail("character"))
	    takeprec();
	  break;
	case 'd':
	  if (tail("double"))
	    {
	      while (isspace(*dbp))
		dbp++;
	      if (*dbp == 0)
		continue;
	      if (tail("precision"))
		break;
	      continue;
	    }
	  break;
	}
      while (isspace(*dbp))
	dbp++;
      if (*dbp == 0)
	continue;
      switch (*dbp|' ')
	{
	case 'f':
	  if (tail("function"))
	    getit();
	  continue;
	case 's':
	  if (tail("subroutine"))
	    getit();
	  continue;
	case 'p':
	  if (tail("program"))
	    {
	      getit();
	      continue;
	    }
	  if (tail("procedure"))
	    getit();
	  continue;
	}
    }
  return (pfcnt);
}

tail(cp)
     char *cp;
{
  register int len = 0;

  while (*cp && (*cp&~' ') == ((*(dbp+len))&~' '))
    cp++, len++;
  if (*cp == 0)
    {
      dbp += len;
      return (1);
    }
  return (0);
}

takeprec()
{
  while (isspace(*dbp))
    dbp++;
  if (*dbp != '*')
    return;
  dbp++;
  while (isspace(*dbp))
    dbp++;
  if (!isdigit(*dbp))
    {
      --dbp;		/* force failure */
      return;
    }
  do
    dbp++;
  while (isdigit(*dbp));
}

getit()
{
  register char *cp;
  char c;
  char nambuf[BUFSIZ];

  while (isspace(*dbp))
    dbp++;
  if (*dbp == 0 || !isalpha(*dbp))
    return;
  for (cp = dbp+1; *cp && (isalpha(*cp) || isdigit(*cp)); cp++)
    continue;
  c = cp[0];
  cp[0] = 0;
  strcpy(nambuf, dbp);
  cp[0] = c;
  pfnote(nambuf, TRUE, lb.buffer, cp - lb.buffer + 1, lineno, linecharno);
  pfcnt++;
}

/*
 * lisp tag functions
 * just look for (def or (DEF
 */

L_funcs (fi)
     FILE *fi;
{
  lineno = 0;
  charno = 0;
  pfcnt = 0;

  while (!feof (fi))
    {
      lineno++;
      linecharno = charno;
      charno += readline (&lb, fi) + 1;
      dbp = lb.buffer;
      if (dbp[0] == '(' && 
	  (dbp[1] == 'D' || dbp[1] == 'd') &&
	    (dbp[2] == 'E' || dbp[2] == 'e') &&
	      (dbp[3] == 'F' || dbp[3] == 'f'))
	{
	  while (!isspace(*dbp)) dbp++;
	  while (isspace(*dbp)) dbp++;
	  L_getit();
	}
    }
}

L_getit()
{
  register char *cp;
  char c;
  char nambuf[BUFSIZ];

  if (*dbp == 0) return;
  for (cp = dbp+1; *cp && *cp != '(' && *cp != ' '; cp++)
    continue;
  c = cp[0];
  cp[0] = 0;
  strcpy(nambuf, dbp);
  cp[0] = c;
  pfnote(nambuf, TRUE, lb.buffer, cp - lb.buffer + 1, lineno, linecharno);
  pfcnt++;
}

/* Initialize a linebuffer for use */

void
initbuffer (linebuffer)
     struct linebuffer *linebuffer;
{
  linebuffer->size = 200;
  linebuffer->buffer = (char *) xmalloc (200);
}

/* Read a line of text from `stream' into `linebuffer'.
 Return the length of the line.  */

long
readline (linebuffer, stream)
     struct linebuffer *linebuffer;
     register FILE *stream;
{
  char *buffer = linebuffer->buffer;
  register char *p = linebuffer->buffer;
  register char *pend = p + linebuffer->size;

  while (1)
    {
      int c = getc (stream);
      if (p == pend)
	{
	  buffer = (char *) xrealloc (buffer, linebuffer->size *= 2);
	  p += buffer - linebuffer->buffer;
	  pend += buffer - linebuffer->buffer;
	  linebuffer->buffer = buffer;
	}
      if (c < 0 || c == '\n')
	{
	  *p = 0;
	  break;
	}
      *p++ = c;
    }

  return p - buffer;
}

char *
savestr(cp)
     char *cp;
{
  register int len;
  register char *dp;

  len = strlen(cp);
  dp = (char *)xmalloc(len+1);
  strcpy(dp, cp);
  return (dp);
}

/*
 * Return the ptr in sp at which the character c last
 * appears; NULL if not found
 *
 * Identical to v7 rindex, included for portability.
 */

char *
rindex(sp, c)
     register char *sp, c;
{
  register char *r;

  r = NULL;
  do
    {
      if (*sp == c)
	r = sp;
    } while (*sp++);
  return(r);
}

/* Print error message and exit.  */

fatal (s1, s2)
     char *s1, *s2;
{
  error (s1, s2);
  exit (1);
}

/* Print error message.  `s1' is printf control string, `s2' is arg for it. */

error (s1, s2)
     char *s1, *s2;
{
#ifdef CTAGS
  printf ("ctags: ");
#else
  printf ("etags: ");
#endif
  printf (s1, s2);
  printf ("\n");
}

/* Return a newly-allocated string whose contents concatenate those of s1, s2, s3.  */

char *
concat (s1, s2, s3)
     char *s1, *s2, *s3;
{
  int len1 = strlen (s1), len2 = strlen (s2), len3 = strlen (s3);
  char *result = (char *) xmalloc (len1 + len2 + len3 + 1);

  strcpy (result, s1);
  strcpy (result + len1, s2);
  strcpy (result + len1 + len2, s3);
  *(result + len1 + len2 + len3) = 0;

  return result;
}

/* Like malloc but get fatal error if memory is exhausted.  */

int
xmalloc (size)
     int size;
{
  int result = malloc (size);
  if (!result)
    fatal ("virtual memory exhausted", 0);
  return result;
}

int
xrealloc (ptr, size)
     char *ptr;
     int size;
{
  int result = realloc (ptr, size);
  if (!result)
    fatal ("virtual memory exhausted");
  return result;
}