/* Tags file maker to go with GNUmacs
   Copyright (C) 1984, 1987, 1988 Free Software Foundation, Inc. and Ken Arnold

    This program 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 1, or (at your option)
    any later version.

    This program 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 this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

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.
 Define neither one to get behavior that depends
 on the name with which the program is invoked
 (but we don't normally compile it that way).  */

/* On VMS, CTAGS is not useful, so always do ETAGS.  */
#ifdef VMS
#ifndef ETAGS
#define ETAGS
#endif
#endif

/* Exit codes for success and failure.  */

#ifdef VMS
#define	GOOD	(1)
#define BAD	(0)
#else
#define	GOOD	(0)
#define	BAD	(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)

/* cause token checking for typedef, struct, union, enum to distinguish
   keywords from identifier-prefixes (e.g. struct vs struct_tag).  */
#define istoken(s, tok, len) (!strncmp(s,tok,len) && endtoken(*((s)+(len))))

struct	nd_st {			/* sorting structure			*/
	char	*name;			/* 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, tag_ok, middle, end } TYST;

TYST tydef = none;

logical next_token_is_func;

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= 0,		/* output file				*/
	*white	= " \f\t\n",	/* white chars				*/
	*endtk	= " \t\n\"'#()[]{}=-+%*/&|^~!<>;,.:?",
				/* token ending chars			*/
	*begtk	= "ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz$",
				/* token starting chars			*/
	*intk	= "ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz$0123456789",
				/* valid in-token chars			*/
	*notgd	= ",;";		/* non-valid after-function chars	*/

int	file_num = 0;		/* current file number			*/
int	aflag = 0;		/* -a: append to tags */
int	tflag = 0;		/* -t: create tags for typedefs */
int	uflag = 0;		/* -u: update tags */
int	wflag = 0;		/* -w: suppress warnings */
int	vflag = 0;		/* -v: create vgrind style index output */
int	xflag = 0;		/* -x: create cxref style output */
int	eflag = 0;		/* -e: emacs style output */

/* Name this program was invoked with.  */
char *progname;

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

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

char *savestr();
char *savenstr ();
char *rindex();
char *index();
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;

#if 0  /* VMS now provides the `system' function.  */
#ifdef VMS

#include <descrip.h>

void
system (buf)
     char *buf;
{
  struct dsc$descriptor_s command =
    {
      strlen(buf), DSC$K_DTYPE_T, DSC$K_CLASS_S, buf
    };

  LIB$SPAWN(&command);
}
#endif /* VMS */
#endif /* 0 */

main(ac,av)
     int	ac;
     char	*av[];
{
  char cmd[100];
  int i;
  int fflag = 0;
  char *this_file;
#ifdef VMS
  char got_err;

  extern char *gfnames();
  extern char *massage_name();
#endif

  progname = av[0];

#ifdef ETAGS
  eflag = 1;
#else
  eflag = 0;
#endif

  while (ac > 1 && av[1][0] == '-')
    {
      for (i=1; av[1][i]; i++)
	{
	  switch(av[1][i])
	    {
#ifndef VMS  /* These options are useful only with ctags,
		and VMS can't input them, so just omit them.  */
	    case 'B':
	      searchar='?';
	      eflag = 0;
	      break;
	    case 'F':
	      searchar='/';
	      eflag = 0;
	      break;
#endif
	    case 'a':
	      aflag++;
	      break;
	    case 'e':
	      eflag++;
	      break;
	    case 'f':
	      if (fflag > 0)
		{
		  fprintf(stderr,
			  "%s: -f flag may only be given once\n", progname);
		  goto usage;
		}
	      fflag++, ac--; av++;
	      if (ac <= 1 || av[1][0] == '\0')
		{
		  fprintf(stderr,
			  "%s: -f flag must be followed by a filename\n",
			  progname);
		  goto usage;
		}
	      outfile = av[1];
	      goto end_loop;
	    case 't':
	      tflag++;
	      break;
#ifndef VMS
	    case 'u':
	      uflag++;
	      eflag = 0;
	      break;
#endif
	    case 'w':
	      wflag++;
	      break;
	    case 'v':
	      vflag++;
	      xflag++;
	      eflag = 0;
	      break;
	    case 'x':
	      xflag++;
	      eflag = 0;
	      break;
	    default:
	      goto usage;
	    }
	}
    end_loop: ;
      ac--; av++;
    }

  if (ac <= 1)
    {
    usage:
#ifdef VMS
      fprintf (stderr, "Usage: %s [-aetwvx] [-f outfile] file ...\n", progname);
#else
      fprintf (stderr, "Usage: %s [-BFaetuwvx] [-f outfile] file ...\n", progname);
#endif
      exit(BAD);
    }

  if (outfile == 0)
    {
      outfile = eflag ? "TAGS" : "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)
	{
	  fprintf (stderr, "%s: ", progname);
	  perror (outfile);
	  exit (BAD);
	}
    }

  file_num = 1;
#ifdef VMS
  for (ac--, av++;
       (this_file = gfnames (&ac, &av, &got_err)) != NULL; file_num++)
    {
      if (got_err)
	{
	  error("Can't find file %s\n", this_file);
	  ac--, av++;
	}
      else
	{
	  this_file = massage_name (this_file);
#else     
  for (; file_num < ac; file_num++)
    {
      this_file = av[file_num];
      if (1)
	{
#endif
	  find_entries (this_file);
	  if (eflag)
	    {
	      fprintf (outf, "\f\n%s,%d\n",
		       this_file, total_size_of_entries (head));
	      put_entries (head);
	      free_tree (head);
	      head = NULL;
	    }
	}
    }

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

  if (xflag)
    {
      put_entries(head);
      exit(GOOD);
    }
  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)
    {
      fprintf (stderr, "%s: ", outfile);
      perror(outfile);
      exit(BAD);
    }
  put_entries(head);
  fclose(outf);
#ifndef VMS
  if (uflag)
    {
      sprintf(cmd, "sort %s -o %s", outfile, outfile);
      system(cmd);
    }
#endif
  exit(GOOD);
}

/*
 * 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)
    {
      fprintf (stderr, "%s: ", progname);
      perror(file);
      return;
    }
  curfile = savestr(file);
  cp = rindex(file, '.');
  /* .tex, .aux or .bbl implies LaTeX source code */
  if (cp && (!strcmp (cp + 1, "tex") || !strcmp (cp + 1, "aux")
	     || !strcmp (cp + 1, "bbl")))
    {
      TEX_funcs(inf);
      fclose(inf);
      return;
    }
  /* .l or .el or .lisp (or .cl or .clisp or ...) implies lisp source code */
  if (cp && (!strcmp (cp + 1, "l") ||
	     !strcmp (cp + 1, "el") ||
	     !strcmp (cp + 1, "lsp") ||
	     !strcmp (cp + 1, "lisp") ||
	     !strcmp (cp + 1, "cl") ||
	     !strcmp (cp + 1, "clisp")))
    {
      L_funcs(inf);
      fclose(inf);
      return;
    }
  /* .scm or .sm or .scheme implies scheme source code */
  if (cp && (!strcmp (cp + 1, "sm")
	     || !strcmp (cp + 1, "scm")
	     || !strcmp (cp + 1, "scheme")
	     || !strcmp (cp + 1, "t")
	     || !strcmp (cp + 1, "sch")
	     || !strcmp (cp + 1, "SM")
	     || !strcmp (cp + 1, "SCM")
             /* The `SCM' or `scm' prefix with a version number */
             || (cp[-1] == 'm' && cp[-2] == 'c' && cp[-3] == 's'
		 && string_numeric_p (cp + 1))
             || (cp[-1] == 'M' && cp[-2] == 'C' && cp[-3] == 'S'
		 && string_numeric_p (cp + 1))))
    {
      Scheme_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);
}

/* Nonzero if string STR is composed of digits.  */

int
string_numeric_p (str)
     char *str;
{
  while (*str)
    {
      if (*str < '0' || *str > '9')
	return 0;
    }
  return 1;
}

/* 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, "%s: too many entries to sort\n", progname);
      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->name = 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->name, cur_node->name);

  /* 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,"%s: Duplicate entry in file %s, line %d: %s\n",
		      progname, node->file,lineno,node->name);
	      fprintf(stderr,"Second entry ignored\n");
	    }
	  return;
	}
      if (!cur_node->been_warned)
	if (!wflag)
	  fprintf(stderr,"%s: Duplicate entry in files %s and %s: %s (Warning only)\n",
		  progname, node->file, cur_node->file, node->name);
      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->name, 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->name, node->file, (node->lno+63)/64);
  else
    fprintf (stdout, "%-16s%4d %-16s %s\n",
	     node->name, 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.
 */
#ifdef VMS
long vmslinecharno;
#define VMS_SET_LINECHARNO	(vmslinecharno = ftell(inf))
#else
#define VMS_SET_LINECHARNO
#endif

#define CNL_SAVE_NUMBER \
{ \
  VMS_SET_LINECHARNO; \
  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;
  tydef = none;
  next_token_is_func = 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 == tag_ok)
	    {
	      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;
#ifdef VMS
		  long vmslinestart = vmslinecharno;
#endif
		  int tem = consider_token (&lp1, token, &f, level);
		  lp = lp1;
		  if (tem)
		    {
		      if (linestart != linecharno)
			{
#ifdef VMS
			  getline (vmslinestart);
#else
			  getline (linestart);
#endif
			  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, level)
     char **lpp, *token;
     int *f, level;
{
  reg char *lp = *lpp;
  reg char c;
  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 && istoken(token, "typedef", 7))
    {
      tydef=begin;
      goto badone;
    }
  if (tydef==begin && (istoken(token, "struct", 6) ||
		       istoken(token, "union", 5) || istoken(token, "enum", 4)))
  {
    tydef=tag_ok;      
    goto badone;
  }
  if (tydef==tag_ok)
    {
      tydef=middle;
      goto badone;
    }
  if (tydef==begin)		/* e.g. typedef ->int<- */
    {
      tydef=end;
      goto badone;
    }
  if (tydef==middle && level == 0) /* e.g. typedef struct tag ->struct_t<- */
    {
      tydef=end;
    }
  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 == 0)
	{
	  if (feof (inf))
	    break;
	  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)) && (*dbp != '_') && (*dbp != '$'))
    return;
  for (cp = dbp + 1; *cp && (isalpha (*cp) || isdigit (*cp)
			     || (*cp == '_') || (*cp == '$')); 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++;
}

/*
 * 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++;
}

/*
 * Scheme tag functions
 * look for (def... xyzzy
 * look for (def... (xyzzy
 * look for (def ... ((...(xyzzy ....
 * look for (set! xyzzy
 */

static get_scheme ();
Scheme_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++;
          /* Skip over open parens and white space */
          while (*dbp && (isspace(*dbp) || *dbp == '(')) dbp++;
	  get_scheme ();
	}
      if (dbp[0] == '(' && 
	  (dbp[1] == 'S' || dbp[1] == 's') &&
	    (dbp[2] == 'E' || dbp[2] == 'e') &&
	      (dbp[3] == 'T' || dbp[3] == 't') &&
                (dbp[4] == '!' || dbp[4] == '!') &&
                  (isspace(dbp[5])))
	{
	  while (!isspace(*dbp)) dbp++;
          /* Skip over white space */
          while (isspace(*dbp)) dbp++;
	  get_scheme ();
	}
    }
}

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

  if (*dbp == 0) return;
  /* Go till you get to white space or a syntactic break */
  for (cp = dbp+1; *cp && *cp != '(' && *cp != ')' && !isspace(*cp); cp++)
    continue;
  /* Null terminate the string there. */
  c = cp[0];
  cp[0] = 0;
  /* Copy the string */
  strcpy(nambuf, dbp);
  /* Unterminate the string */
  cp[0] = c;
  /* Announce the change */
  pfnote(nambuf, TRUE, lb.buffer, cp - lb.buffer + 1, lineno, linecharno);
  pfcnt++;
}

/* Find tags in TeX and LaTeX input files.  */

/* TEX_toktab is a table of TeX control sequences that define tags.
   Each TEX_tabent records one such control sequence.  */

struct TEX_tabent
{
  char *name;
  int len;
};

struct TEX_tabent *TEX_toktab = NULL; /* Table with tag tokens */

/* Default set of control sequences to put into TEX_toktab.
   The value of environment var TEXTAGS is prepended to this.  */

static char *TEX_defenv =
  ":chapter:section:subsection:subsubsection:eqno:label:ref:cite:bibitem:typeout";

struct TEX_tabent *TEX_decode_env (); 

static char TEX_esc = '\\';
static char TEX_opgrp = '{';
static char TEX_clgrp = '}';

/*
 * TeX/LaTeX scanning loop.
 */

TEX_funcs (fi)
    FILE *fi;
{
  char *lasthit;

  lineno = 0;
  charno = 0;
  pfcnt = 0;

  /* Select either \ or ! as escape character.  */
  TEX_mode (fi);

  /* Initialize token table once from environment. */
  if (!TEX_toktab)
    TEX_toktab = TEX_decode_env ("TEXTAGS", TEX_defenv);

  while (!feof (fi))
    {	/* Scan each line in file */
      lineno++;
      linecharno = charno;
      charno += readline (&lb, fi) + 1;
      dbp = lb.buffer;
      lasthit = dbp;
      while (dbp = index (dbp, TEX_esc)) /* Look at each escape in line */
	{
	  register int i;

	  if (! *(++dbp))
	    break;
	  linecharno += dbp - lasthit;
	  lasthit = dbp;
	  i = TEX_Token (lasthit);
	  if (0 <= i)
	    {
	      TEX_getit (lasthit, TEX_toktab[i].len);
	      break;		/* We only save a line once */
	    }
	}
    }
}

#define TEX_LESC '\\'
#define TEX_SESC '!'
#define TEX_CMT  '%'

/* Figure out whether TeX's escapechar is '\\' or '!' and set grouping */
/* chars accordingly. */

TEX_mode (f)
     FILE *f;
{
  int c, skip_line = 0;

  while ((c = getc (f)) != EOF)
    {
      /* Skip to next line if we hit the TeX comment char. */
      if (c == TEX_CMT)
	skip_line = 1;
      else if (c == '\n')
	skip_line = 0;
      else if (! skip_line)
	if (c == TEX_LESC || c == TEX_SESC)
	  break;
    }

  if (c == TEX_LESC)
    {
      TEX_esc = TEX_LESC;
      TEX_opgrp = '{';
      TEX_clgrp = '}';
    } 
  else
    {
      TEX_esc = TEX_SESC;
      TEX_opgrp = '<';
      TEX_clgrp = '>';
    }
  rewind (f);
}

/* Read environment and prepend it to the default string. */
/* Build token table. */

struct TEX_tabent *
TEX_decode_env (evarname, defenv)
     char *evarname;
     char *defenv;
{
  register char *env, *p;
  extern char *savenstr (), *index ();

  struct TEX_tabent *tab;
  int size, i;

  /* Append deafult string to environment. */
  env = (char *) getenv (evarname);
  if (!env)
    env = defenv;
  else
    env = concat (env, defenv, "");

  /* Allocate a token table */
  for (size = 1, p=env; p;)
    if ((p = index (p, ':')) && *(++p))
      size++;
  tab = (struct TEX_tabent *) xmalloc ((size + 1)
				       * sizeof (struct TEX_tabent));

  /* Unpack environment string into token table. Be careful about */
  /* zero-length strings (leading ':', "::" and trailing ':') */
  for (i = 0; *env;)
    {
      p = index (env, ':');
      if (!p)			/* End of environment string. */
	p = env + strlen (env);
      if (p - env > 0)
	{	/* Only non-zero strings. */
	  tab[i].name = savenstr (env, p - env);
	  tab[i].len = strlen (tab[i].name);
	  i++;
	}
      if (*p)
	env = p + 1;
      else
	{
	  tab[i].name = NULL;	/* Mark end of table. */
	  tab[i].len = 0;
	  break;
	}
    }
  return tab;
}

/* Record a tag defined by a TeX command of length LEN and starting at NAME.
   The name being defined actually starts at (NAME + LEN + 1).
   But we seem to include the TeX command in the tag name.  */

TEX_getit (name, len)
    char *name;
    int len;
{
  char *p = name + len;
  char nambuf[BUFSIZ];

  if (*name == 0) return;

  /* Let tag name extend to next group close (or end of line) */
  while (*p && *p != TEX_clgrp)
    p++;
  strncpy (nambuf, name, p - name);
  nambuf[p - name] = 0;

  pfnote (nambuf, TRUE, lb.buffer, strlen (lb.buffer), lineno, linecharno);
  pfcnt++;
}

/* If the text at CP matches one of the tag-defining TeX command names,
   return the index of that command in TEX_toktab.
   Otherwise return -1.  */

/* Keep the capital `T' in `Token' for dumb truncating compilers
   (this distinguishes it from `TEX_toktab' */
TEX_Token (cp)
    char *cp;
{
  int i;

  for (i = 0; TEX_toktab[i].len > 0; i++)
    if (strncmp (TEX_toktab[i].name, cp, TEX_toktab[i].len) == 0)
      return i;
  return -1;
}

/* 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;

  pend = p + linebuffer->size;

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

  return p - buffer;
}

char *
savestr(cp)
     char *cp;
{
  return savenstr (cp, strlen (cp));
}

char *
savenstr(cp, len)
    char *cp;
    int len;
{
  register char *dp;

  dp = (char *) xmalloc (len + 1);
  strncpy (dp, cp, len);
  dp[len] = '\0';
  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);
}

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

char *
index(sp, c)
     register char *sp, c;
{
  do
    {
      if (*sp == c)
	return (sp);
    } while (*sp++);
  return (NULL);
}

/* Print error message and exit.  */

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

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

error (s1, s2)
     char *s1, *s2;
{
  fprintf (stderr, "%s: ", progname);
  fprintf (stderr, s1, s2);
  fprintf (stderr, "\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;
}
