/* Work-alike for termcap, plus extra features.
   Copyright (C) 1985 Richard M. Stallman.

This file is part of GNU Emacs.

GNU Emacs 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.  Refer to the GNU Emacs General Public
License for full details.

Everyone is granted permission to copy, modify and redistribute
GNU Emacs, but only under the conditions described in the
GNU Emacs General Public License.   A copy of this license is
supposed to have been given to you along with GNU Emacs so you
can know your rights and responsibilities.  It should be in a
file named COPYING.  Among other things, the copyright notice
and this notice must be preserved on all copies.  */



/* BUFSIZE is the initial size allocated for the buffer
   for reading the termcap file.
   It is not a limit.
   Make it large normally for speed.
   Make it variable when debugging, so can exercise
   increasing the space dynamically.  */

#ifndef BUFSIZE
#ifdef DEBUG
#define BUFSIZE bufsize

int bufsize = 128;
#else
#define BUFSIZE 2048
#endif
#endif

static
memory_out ()
{
  write (2, "Virtual memory exhausted\n", 25);
  exit (1);
}

static int
xmalloc (size)
     int size;
{
  register tem = malloc (size);
  if (!tem)
    memory_out ();
  return tem;
}

static int
xrealloc (ptr, size)
     int ptr;
     int size;
{
  register tem = realloc (ptr, size);
  if (!tem)
    memory_out ();
  return tem;
}

/* Looking up capabilities in the entry already found */

/* The pointer to the data made by tgetent is left here
   for tgetnum, tgetflag and tgetstr to find.  */

static char *term_entry;

static char *tgetst1 ();

/* This is the main subroutine that is used to search
   an entry for a particular capability */

static char *
find_capability (bp, cap)
     register char *bp, *cap;
{
  for (; *bp; bp++)
    if (bp[0] == ':'
	&& bp[1] == cap[0]
	&& bp[2] == cap[1])
      return &bp[4];
  return 0;
}

int
tgetnum (cap)
     char *cap;
{
  register char *ptr = find_capability (term_entry, cap);
  if (!ptr || ptr[-1] != '#')
    return -1;
  return atoi (ptr);
}

int
tgetflag (cap)
     char *cap;
{
  register char *ptr = find_capability (term_entry, cap);
  return 0 != ptr && ptr[-1] == ':';
}

/* Look up a string-valued capability `cap'.
   If `area' is nonzero, it points to a pointer to a block in which
   to store the string.  That pointer is advanced over the space used.
   If `area' is zero, space is allocated with `malloc'.  */

char *
tgetstr (cap, area)
     char *cap;
     char **area;
{
  register char *ptr = find_capability (term_entry, cap);
  if (!ptr || (ptr[-1] != '=' && ptr[-1] != '~'))
    return 0;
  return tgetst1 (ptr, area);
}

/* Table, indexed by a character in range 0100 to 0140 with 0100 subtracted,
   gives meaning of character following \, or a space if no special meaning.
   Eight characters per line within the string.  */

static char esctab[]
  = " \007\010  \033\014 \
      \012 \
  \015 \011 \013 \
        ";

/* Given a pointer to a string value inside a termcap entry (`ptr'),
   copy the value and process \ and ^ abbreviations.
   Copy into block that *area points to,
   or to newly allocated storage if area is 0.  */

static char *
tgetst1 (ptr, area)
     char *ptr;
     char **area;
{
  register char *p, *r;
  register int c;
  register int size;
  char *ret;
  register int c1;

  if (!ptr)
    return 0;

  /* `ret' gets address of where to store the string */
  if (!area)
    {
      /* Compute size of block needed (may overestimate) */
      p = ptr;
      while ((c = *p++) && c != ':');
      ret = (char *) xmalloc (p - ptr + 1);
    }
  else
    ret = *area;

  /* Copy the string value, stopping at null or colon.  */
  /* Also process ^ and \ abbreviations.  */
  p = ptr;
  r = ret;
  while ((c = *p++) && c != ':')
    {
      if (c == '^')
	c = *p++ & 037;
      else if (c == '\\')
	{
	  c = *p++;
	  if (c >= '0' && c <= '7')
	    {
	      c -= '0';
	      size = 0;

	      while (++size < 3 && (c1 = *p) >= '0' && c1 <= '7')
		{
		  c *= 8;
		  c += c1 - '0';
		  p++;
		}
	    }
	  else if (c >= 0100 && c < 0200)
	    {
	      c1 = esctab[(c & ~040) - 0100];
	      if (c1 != ' ')
		c = c1;
	    }
	}
      *r++ = c;
    }
  *r = 0;
  /* Update *area */
  if (area)
    *area = r + 1;
  return ret;
}

/* Outputting a string with padding */

short ospeed;
char PC;

/* Actual baud rate if positive;
   - baud rate / 100 if negative.  */

static short speeds[] =
  {
    0, 50, 75, 110, 135, 150, 200, -3, -6, -12,
    -18, -24, -48, -96, -192, -384
  };

tputs (string, nlines, outfun)
     register char *string;
     int nlines;
     register int (*outfun) ();
{
  register int padcount = 0;

  if (string == (char *) 0)
    return;
  while (*string >= '0' && *string <= '9')
    {
      padcount += *string++ - '0';
      padcount *= 10;
    }
  if (*string == '.')
    {
      string++;
      padcount += *string++ - '0';
    }
  if (*string == '*')
    {
      string++;
      padcount *= nlines;
    }
  while (*string)
    (*outfun) (*string++);

  /* padcount is now in units of tenths of msec.  */
  padcount *= speeds[ospeed];
  padcount /= 1000;
  if (speeds[ospeed] < 0)
    padcount = -padcount;
  else
    padcount /= 100;

  while (padcount-- > 0)
    (*outfun) (PC);
}

/* Finding the termcap entry in the termcap data base */

struct buffer
  {
    char *beg;
    int size;
    char *ptr;
    int ateof;
    int full;
  };

/* Forward declarations of static functions */

static int scan_file ();
static char *gobble_line ();
static int compare_contin ();
static int name_match ();

/* Find the termcap entry data for terminal type `name'
   and store it in the block that `bp' points to.
   Record its address for future use.

   If `bp' is zero, space is dynamically allocated.  */

int
tgetent (bp, name)
     char *bp, *name;
{
  register char *tem;
  register int fd;
  struct buffer buf;
  register char *bp1;
  char *bp2;
  char *term;
  int malloc_size = 0;
  register int c;

  tem = (char *) getenv ("TERMCAP");

  /* If tem is non-null and starts with /,
     it is a file name to use instead of /etc/termcap.
     If it is non-null and does not start with /,
     it is the entry itself, but only if it contains
     a name matching NAME.  */

  if (tem && *tem != '/' && name_match (tem, name))
    {
      if (!bp)
	bp = tem;
      else
	strcpy (bp, tem);
      goto ret;
    }

  if (!tem)
    tem = "/etc/termcap";

  /* Here we know we must search a file and tem has its name.  */

  fd = open (tem, 0, 0);
  if (fd < 0)
    return -1;

  buf.size = BUFSIZE;
  buf.beg = (char *) xmalloc (buf.size);
  term = name;

  if (!bp)
    {
      malloc_size = buf.size;
      bp = (char *) xmalloc (malloc_size);
    }
  bp1 = bp;

  while (term)
    {
      /* Scan file, reading it via buf, till find start of main entry */
      if (scan_file (term, fd, &buf) == 0)
	return 0;

      /* Free old `term' if appropriate.  */
      if (term != name)
	free (term);

      /* If `bp' is malloc'd by us, make sure it is big enough.  */
      if (malloc_size)
	{
	  malloc_size = bp1 - bp + buf.size;
	  tem = (char *) xrealloc (bp, malloc_size);
	  bp1 += tem - bp;
	  bp = tem;
	}

      bp2 = bp1;

      /* Copy the line of the entry from buf into bp.  */
      tem = buf.ptr;
      while ((*bp1++ = c = *tem++) && c != '\n')
	/* Drop out any \ newline sequence, and following whitespace */
	if (c == '\\' && *tem == '\n')
	  {
	    bp1--;
	    tem++;
	    while ((c = *tem++) == ' ' || c == '\t');
	    tem--;
	  }
      *bp1 = 0;

      /* Does this entry refer to another terminal type's entry?  */
      /* If something is found, copy it into heap and null-terminate it */
      term = tgetst1 (find_capability (bp2, "tc", '='), 0);
    }

  close (fd);
  free (buf.beg);

  if (malloc_size)
    {
      bp = (char *) xrealloc (bp, bp1 - bp + 1);
    }

 ret:
  term_entry = bp;
  if (malloc_size)
    return (int) bp;
  return 1;
}

/* Given file open on `fd' and buffer `bufp',
   scan the file from the beginning until a line is found
   that starts the entry for terminal type `string'.
   Returns 1 if successful, with that line in `bufp',
   or returns 0 if no entry found in the file.  */

static int
scan_file (string, fd, bufp)
     char *string;
     int fd;
     register struct buffer *bufp;
{
  register char *tem;
  register char *end;

  bufp->ptr = bufp->beg;
  bufp->full = 0;
  bufp->ateof = 0;
  *bufp->ptr = 0;

  lseek (fd, 0L, 0);

  while (!bufp->ateof)
    {
      /* Read a line into the buffer */
      end = 0;
      do
	{
	  /* if it is continued, append another line to it,
	     until a non-continued line ends */
	  end = gobble_line (fd, bufp, end);
	}
      while (!bufp->ateof && end[-2] == '\\');

      if (*bufp->ptr != '#'
	  && name_match (bufp->ptr, string))
	return 1;

      /* Discard the line just processed */
      bufp->ptr = end;
    }
  return 0;
}

/* Return nonzero if NAME is one of the names specified
   by termcap entry LINE.  */

static int
name_match (line, name)
     char *line, *name;
{
  register char *tem;

  if (!compare_contin (line, name))
    return 1;
  /* This line starts an entry.  Is it the right one?  */
  for (tem = line; *tem && *tem != '\n' && *tem != ':'; tem++)
    if (*tem == '|' && !compare_contin (tem + 1, name))
      return 1;

  return 0;
}

static int
compare_contin (str1, str2)
     register char *str1, *str2;
{
  register int c1, c2;
  while (1)
    {
      c1 = *str1++;
      c2 = *str2++;
      while (c1 == '\\' && *str1 == '\n')
	{
	  str1++;
	  while ((c1 = *str1++) == ' ' || c1 == '\t');
	}
      if (c2 == '\0')		/* end of type being looked up */
	{
	  if (c1 == '|' || c1 == ':') /* If end of name in data base, */
	    return 0;		/* we win. */
	  else
	    return 1;
        }
      else if (c1 != c2)
	return 1;
    }
}

/* Make sure that the buffer <- `bufp' contains a full line
   of the file open on `fd', starting at the place `bufp->ptr'
   points to.  Can read more of the file, discard stuff before
   `bufp->ptr', or make the buffer bigger.

   Returns the pointer to after the newline ending the line,
   or to the end of the file, if there is no newline to end it.

   Can also merge on continuation lines.  If `append_end' is
   nonzero, it points past the newline of a line that is
   continued; we add another line onto it and regard the whole
   thing as one line.  The caller decides when a line is continued.  */

static char *
gobble_line (fd, bufp, append_end)
     int fd;
     register struct buffer *bufp;
     char *append_end;
{
  register char *end;
  register int nread;
  register char *buf = bufp->beg;
  register char *tem;

  if (append_end == 0)
    append_end = bufp->ptr;

  while (1)
    {
      end = append_end;
      while (*end && *end != '\n') end++;
      if (*end)
        break;
      if (bufp->ateof)
	return buf + bufp->full;
      if (bufp->ptr == buf)
	{
	  if (bufp->full == bufp->size)
	    {
	      bufp->size *= 2;
	      tem = (char *) xrealloc (buf, bufp->size);
	      bufp->ptr += tem - buf;
	      append_end += tem - buf;
	      bufp->beg = buf = tem;
	    }
	}
      else
	{
	  append_end -= bufp->ptr - buf;
	  bcopy (bufp->ptr, buf, bufp->full -= bufp->ptr - buf);
	  bufp->ptr = buf;
	}
      if (!(nread = read (fd, buf + bufp->full, bufp->size - bufp->full)))
	bufp->ateof = 1;
      bufp->full += nread;
      if (bufp->full != bufp->size)
	buf[bufp->full] = 0;
    }
  return end + 1;
}

#ifdef DEBUG

#include <stdio.h>

main (argc, argv)
     int argc;
     char **argv;
{
  char *term;
  char *buf;

  if (!strcmp (argv[1], "-f"))
    {
      argv++;
      bufsize = 2048;
    }
  term = argv[1];
  printf ("TERM: %s\n", term);

  buf = (char *) tgetent (0, term);
  if ((int) buf <= 0)
    {
      printf ("No entry.\n");
      return 0;
    }

  printf ("Entry: %s\n", buf);

  tprint ("cm");
  tprint ("AL");

  printf ("co: %d\n", tgetnum ("co"));
  printf ("am: %d\n", tgetflag ("am"));
}

tprint (cap)
     char *cap;
{
  char *x = tgetstr (cap, 0);
  register char *y;

  printf ("%s: ", cap);
  if (x)
    {
      for (y = x; *y; y++)
	if (*y <= ' ' || *y == 0177)
	  printf ("\\%0o", *y);
	else
	  putchar (*y);
      free (x);
    }
  else
    printf ("none");
  putchar ('\n');
}

#endif /* DEBUG */