mined1.c

操作系统源代码

  	}
  	count += (long) length_of(line->text);
  }

  if (count > 0L && flush_buffer(fd) == ERRORS)
  	count = -1L;

  (void) close(fd);

  if (count == -1L)
  	return ERRORS;

  modified = FALSE;
  rpipe = FALSE;		/* File name is now assigned */

/* Display how many chars (and lines) were written */
  fstatus("Wrote", count);
  return FINE;
}

/* Call WT and discard value returned. */
void XWT()
{
  (void) WT();
}



/*
 * Call an interactive shell.
 */
void SH()
{
  register int w;
  int pid, status;
  char *shell;

  if ((shell = getenv("SHELL")) == NIL_PTR) shell = "/bin/sh";

  switch (pid = fork()) {
  	case -1:			/* Error */
  		error("Cannot fork.", NIL_PTR);
  		return;
  	case 0:				/* This is the child */
  		set_cursor(0, ymax);
  		putchar('\n');
  		flush();
  		raw_mode(OFF);
		if (rpipe) {			/* Fix stdin */
			close (0);
			if (open("/dev/tty", 0) < 0)
				exit (126);
		}
  		execl(shell, shell, (char *) 0);
  		exit(127);			/* Exit with 127 */
  	default :				/* This is the parent */
  		signal(SIGINT, SIG_IGN);
  		signal(SIGQUIT, SIG_IGN);
  		do {
  			w = wait(&status);
  		} while (w != -1 && w != pid);
  }

  raw_mode(ON);
  RD();

  if ((status >> 8) == 127)		/* Child died with 127 */
  	error("Cannot exec ", shell);
  else if ((status >> 8) == 126)
  	error("Cannot open /dev/tty as fd #0", NIL_PTR);
}

/*
 * Proceed returns the count'th line after `line'. When count is negative
 * it returns the count'th line before `line'. When the next (previous)
 * line is the tail (header) indicating EOF (tof) it stops.
 */
LINE *proceed(line, count)
register LINE *line;
register int count;
{
  if (count < 0)
  	while (count++ < 0 && line != header)
  		line = line->prev;
  else
  	while (count-- > 0 && line != tail)
  		line = line->next;
  return line;
}

/*
 * Show concatenation of s1 and s2 on the status line (bottom of screen)
 * If revfl is TRUE, turn on reverse video on both strings. Set stat_visible
 * only if bottom_line is visible.
 */
int bottom_line(revfl, s1, s2, inbuf, statfl)
FLAG revfl;
char *s1, *s2;
char *inbuf;
FLAG statfl;
{
  int ret = FINE;
  char buf[LINE_LEN];
  register char *p = buf;

  *p++ = ' ';
  if (s1 != NIL_PTR)
	while (*p = *s1++)
		p++;
  if (s2 != NIL_PTR)
	while (*p = *s2++)
		p++;
  *p++ = ' ';
  *p++ = 0;

  if (revfl == ON && stat_visible == TRUE)
	clear_status ();
  set_cursor(0, ymax);
  if (revfl == ON) {		/* Print rev. start sequence */
#ifdef UNIX
  	tputs(SO, 0, _putchar);
#else
  	string_print(rev_video);
#endif /* UNIX */
  	stat_visible = TRUE;
  }
  else				/* Used as clear_status() */
  	stat_visible = FALSE;

  string_print(buf);
  
  if (inbuf != NIL_PTR)
  	ret = input(inbuf, statfl);

  /* Print normal video */
#ifdef UNIX
  tputs(SE, 0, _putchar);
  tputs(CE, 0, _putchar);
#else
  string_print(normal_video);
  string_print(blank_line);	/* Clear the rest of the line */
#endif /* UNIX */
  if (inbuf != NIL_PTR)
  	set_cursor(0, ymax);
  else
  	set_cursor(x, y);	/* Set cursor back to old position */
  flush();			/* Perform the actual write */
  if (ret != FINE)
  	clear_status();
  return ret;
}

/*
 * Count_chars() count the number of chars that the line would occupy on the
 * screen. Counting starts at the real x-coordinate of the line.
 */
int count_chars(line)
LINE *line;
{
  register int cnt = get_shift(line->shift_count) * -SHIFT_SIZE;
  register char *textp = line->text;

/* Find begin of line on screen */
  while (cnt < 0) {
  	if (is_tab(*textp++))
  		cnt = tab(cnt);
  	else
  		cnt++;
  }

/* Count number of chars left */
  cnt = 0;
  while (*textp != '\n') {
  	if (is_tab(*textp++))
  		 cnt = tab(cnt);
  	else
  		cnt++;
  }
  return cnt;
}

/*
 * Move to coordinates nx, ny at screen.  The caller must check that scrolling
 * is not needed.
 * If new_x is lower than 0 or higher than XBREAK, move_to() will check if
 * the line can be shifted. If it can it sets(or resets) the shift_count field
 * of the current line accordingly.
 * Move also sets cur_text to the right char.
 * If we're moving to the same x coordinate, try to move the the x-coordinate
 * used on the other previous call.
 */
void move(new_x, new_address, new_y)
register int new_x;
int new_y;
char *new_address;
{
  register LINE *line = cur_line;	/* For building new cur_line */
  int shift = 0;			/* How many shifts to make */
  static int rel_x = 0;		/* Remember relative x position */
  int tx = x;

/* Check for illegal values */
  if (new_y < 0 || new_y > last_y)
  	return;

/* Adjust y-coordinate and cur_line */
  if (new_y < y)
  	while (y != new_y) {
  		y--;
  		line = line->prev;
  	}
  else
  	while (y != new_y) {
  		y++;
  		line = line->next;
  	}

/* Set or unset relative x-coordinate */
  if (new_address == NIL_PTR) {
  	new_address = find_address(line, (new_x == x) ? rel_x : new_x , &tx);
	if (new_x != x)
		rel_x = tx;
  	new_x = tx;
  }
  else
  	rel_x = new_x = find_x(line, new_address);

/* Adjust shift_count if new_x lower than 0 or higher than XBREAK */
  if (new_x < 0 || new_x >= XBREAK) {
  	if (new_x > XBREAK || (new_x == XBREAK && *new_address != '\n'))
  		shift = (new_x - XBREAK) / SHIFT_SIZE + 1;
  	else {
  		shift = new_x / SHIFT_SIZE;
		if (new_x % SHIFT_SIZE)
			shift--;
  	}

  	if (shift != 0) {
  		line->shift_count += shift;
  		new_x = find_x(line, new_address);
  		set_cursor(0, y);
  		line_print(line);
  		rel_x = new_x;
  	}
  }

/* Assign and position cursor */
  x = new_x;
  cur_text = new_address;
  cur_line = line;
  set_cursor(x, y);
}

/*
 * Find_x() returns the x coordinate belonging to address.
 * (Tabs are expanded).
 */
int find_x(line, address)
LINE *line;
char *address;
{
  register char *textp = line->text;
  register int nx = get_shift(line->shift_count) * -SHIFT_SIZE;

  while (textp != address && *textp != '\0') {
  	if (is_tab(*textp++)) 	/* Expand tabs */
  		nx = tab(nx);
  	else
  		nx++;
  }
  return nx;
}

/*
 * Find_address() returns the pointer in the line with offset x_coord.
 * (Tabs are expanded).
 */
char *find_address(line, x_coord, old_x)
LINE *line;
int x_coord;
int *old_x;
{
  register char *textp = line->text;
  register int tx = get_shift(line->shift_count) * -SHIFT_SIZE;

  while (tx < x_coord && *textp != '\n') {
  	if (is_tab(*textp)) {
  		if (*old_x - x_coord == 1 && tab(tx) > x_coord)
  			break;		/* Moving left over tab */
  		else
  			tx = tab(tx);
  	}
  	else
  		tx++;
  	textp++;
  }
  
  *old_x = tx;
  return textp;
}

/*
 * Length_of() returns the number of characters int the string `string'
 * excluding the '\0'.
 */
int length_of(string)
register char *string;
{
  register int count = 0;

  if (string != NIL_PTR) {
  	while (*string++ != '\0')
  		count++;
  }
  return count;
}

/*
 * Copy_string() copies the string `from' into the string `to'. `To' must be
 * long enough to hold `from'.
 */
void copy_string(to, from)
register char *to;
register char *from;
{
  while (*to++ = *from++)
  	;
}

/*
 * Reset assigns bot_line, top_line and cur_line according to `head_line'
 * which must be the first line of the screen, and an y-coordinate,
 * which will be the current y-coordinate (if it isn't larger than last_y)
 */
void reset(head_line, screen_y)
LINE *head_line;
int screen_y;
{
  register LINE *line;

  top_line = line = head_line;

/* Search for bot_line (might be last line in file) */
  for (last_y = 0; last_y < nlines - 1 && last_y < screenmax
						&& line->next != tail; last_y++)
  	line = line->next;

  bot_line = line;
  y = (screen_y > last_y) ? last_y : screen_y;

/* Set cur_line according to the new y value */
  cur_line = proceed(top_line, y);
}

/*
 * Set cursor at coordinates x, y.
 */
void set_cursor(nx, ny)
int nx, ny;
{
#ifdef UNIX
  extern char *tgoto();

  tputs(tgoto(CM, nx, ny), 0, _putchar);
#else
  char text_buffer[10];

  build_string(text_buffer, pos_string, ny+1, nx+1);
  string_print(text_buffer);
#endif /* UNIX */
}

/*
 * Routine to open terminal when mined is used in a pipeline.
 */
void open_device()
{
  if ((input_fd = open("/dev/tty", 0)) < 0)
	panic("Cannot open /dev/tty for read");
}

/*
 * Getchar() reads one character from the terminal. The character must be
 * masked with 0377 to avoid sign extension.
 */
int getchar()
{
#ifdef UNIX
  return (_getchar() & 0377);
#else
  char c;

  if (read(input_fd, &c, 1) != 1 && quit == FALSE)
  	panic("Can't read one char from fd #0");

  return c & 0377;
#endif /* UNIX */
}

/*
 * Display() shows count lines on the terminal starting at the given
 * coordinates. When the tail of the list is encountered it will fill the
 * rest of the screen with blank_line's.
 * When count is negative, a backwards print from `line' will be done.
 */
void display(x_coord, y_coord, line, count)
int x_coord, y_coord;
register LINE *line;
register int count;
{
  set_cursor(x_coord, y_coord);

/* Find new startline if count is negative */
  if (count < 0) {
  	line = proceed(line, count);
  	count = -count;
  }

/* Print the lines */
  while (line != tail && count-- >= 0) {
  	line_print(line);
  	line = line->next;
  }

/* Print the blank lines (if any) */
  if (loading == FALSE) {
	while (count-- >= 0) {
#ifdef UNIX
		tputs(CE, 0, _putchar);
#else
		string_print(blank_line);
#endif /* UNIX */
		putchar('\n');
	}
  }
}

/*
 * Write_char does a buffered output. 
 */
int write_char(fd, c)
int fd;
char c;
{
  screen [out_count++] = c;
  if (out_count == SCREEN_SIZE)		/* Flush on SCREEN_SIZE chars */
  	return flush_buffer(fd);
  return FINE;
}

/*
 * Writeline writes the given string on the given filedescriptor.
 */
int writeline(fd, text)
register int fd;
register char *text;
{
  while(*text)
  	 if (write_char(fd, *text++) == ERRORS)
  		return ERRORS;
  return FINE;
}

/*
 * Put_line print the given line on the standard output. If offset is not zero
 * printing will start at that x-coordinate. If the FLAG clear_line is TRUE,
 * then (screen) line will be cleared when the end of the line has been
 * reached.
 */
void put_line(line, offset, clear_line)
LINE *line;				/* Line to print */
int offset;				/* Offset to start */
FLAG clear_line;			/* Clear to eoln if TRUE */
{
  register char *textp = line->text;
  register int count = get_shift(line->shift_count) * -SHIFT_SIZE;
  int tab_count;			/* Used in tab expansion */

/* Skip all chars as indicated by the offset and the shift_count field */
  while (count < offset) {
  	if (is_tab(*textp++))
  		count = tab(count);
  	else
  		count++;
  }

  while (*textp != '\n' && count < XBREAK) {
  	if (is_tab(*textp)) {		/* Expand tabs to spaces */
  		tab_count = tab(count);
  		while (count < XBREAK && count < tab_count) {
  			count++;
  			putchar(' ');
  		}
  		textp++;
  	}
  	else {
		if (*textp >= '\01' && *textp <= '\037') {