env.cc

早期freebsd实现

    if (tok.ch() == 0)
      error("bad control character");
    else
      curenv->control_char = tok.ch();
  }
  skip_line();
}

void no_break_control_char()
{
  curenv->no_break_control_char = '\'';
  if (has_arg()) {
    if (tok.ch() == 0)
      error("bad control character");
    else
      curenv->no_break_control_char = tok.ch();
  }
  skip_line();
}

void margin_character()
{
  charinfo *ci = get_optional_char();
  if (ci) {
    node *nd = curenv->make_char_node(ci);
    if (nd) {
      delete curenv->margin_character_node;
      curenv->margin_character_node = nd;
      curenv->margin_character_flags = (MARGIN_CHARACTER_ON
					|MARGIN_CHARACTER_NEXT);
      hunits d;
      if (has_arg() && get_hunits(&d, 'm'))
	curenv->margin_character_distance = d;
    }
  }
  else {
    curenv->margin_character_flags &= ~MARGIN_CHARACTER_ON;
    if (curenv->margin_character_flags == 0) {
      delete curenv->margin_character_node;
      curenv->margin_character_node = 0;
    }
  }
  skip_line();
}

void number_lines()
{
  delete_node_list(curenv->numbering_nodes);
  curenv->numbering_nodes = 0;
  if (has_arg()) {
    node *nd = 0;
    for (int i = '9'; i >= '0'; i--) {
      node *tem = make_node(charset_table[i], curenv);
      if (!tem) {
	skip_line();
	return;
      }
      tem->next = nd;
      nd = tem;
    }
    curenv->numbering_nodes = nd;
    curenv->line_number_digit_width = env_digit_width(curenv);
    int n;
    if (!tok.delimiter()) {
      if (get_integer(&n, next_line_number)) {
	next_line_number = n;
	if (next_line_number < 0) {
	  warning(WARN_RANGE, "negative line number");
	  next_line_number = 0;
	}
      }
    }
    else
      while (!tok.space() && !tok.newline() && !tok.eof())
	tok.next();
    if (has_arg()) {
      if (!tok.delimiter()) {
	if (get_integer(&n)) {
	  if (n <= 0) {
	    warning(WARN_RANGE, "negative or zero line number multiple");
	  }
	  else
	    curenv->line_number_multiple = n;
	}
      }
      else
	while (!tok.space() && !tok.newline() && !tok.eof())
	  tok.next();
      if (has_arg()) {
	if (!tok.delimiter()) {
	  if (get_integer(&n))
	    curenv->number_text_separation = n;
	}
	else
	  while (!tok.space() && !tok.newline() && !tok.eof())
	    tok.next();
	if (has_arg() && !tok.delimiter() && get_integer(&n))
	  curenv->line_number_indent = n;
      }
    }
  }
  skip_line();
}

void no_number()
{
  int n;
  if (has_arg() && get_integer(&n))
    curenv->no_number_count = n > 0 ? n : 0;
  else
    curenv->no_number_count = 1;
  skip_line();
}

void no_hyphenate()
{
  curenv->hyphenation_flags = 0;
  skip_line();
}

void hyphenate_request()
{
  int n;
  if (has_arg() && get_integer(&n))
    curenv->hyphenation_flags = n;
  else
    curenv->hyphenation_flags = 1;
  skip_line();
}

void hyphen_char()
{
  curenv->hyphen_indicator_char = get_optional_char();
  skip_line();
}

void hyphen_line_max_request()
{
  int n;
  if (has_arg() && get_integer(&n))
    curenv->hyphen_line_max = n;
  else
    curenv->hyphen_line_max = -1;
  skip_line();
}

void environment::interrupt()
{
  if (!dummy) {
    add_node(new transparent_dummy_node);
    interrupted = 1;
  }
}

void environment::newline()
{
  if (underline_lines > 0) {
    if (--underline_lines == 0) {
      prev_fontno = fontno;
      fontno = pre_underline_fontno;
    }
  }
  if (current_field)
    wrap_up_field();
  if (current_tab)
    wrap_up_tab();
  // strip trailing spaces
  while (line != 0 && line->discardable()) {
    width_total -= line->width();
    space_total -= line->nspaces();
    node *tem = line;
    line = line->next;
    delete tem;
  }
  node *to_be_output = 0;
  hunits to_be_output_width;
  prev_line_interrupted = 0;
  if (dummy)
    space_newline();
  else if (interrupted) {
    interrupted = 0;
    // see environment::final_break
    prev_line_interrupted = exit_started ? 2 : 1;
  }
  else if (center_lines > 0) {
    --center_lines;
    hunits x = target_text_length - width_total;
    if (x > H0)
      saved_indent += x/2;
    to_be_output = line;
    to_be_output_width = width_total;
    line = 0;
  }
  else if (right_justify_lines > 0) {
    --right_justify_lines;
    hunits x = target_text_length - width_total;
    if (x > H0)
      saved_indent += x;
    to_be_output = line;
    to_be_output_width = width_total;
    line = 0;
  }
  else if (fill)
    space_newline();
  else {
    to_be_output = line;
    to_be_output_width = width_total;
    line = 0;
  }
  input_line_start = line == 0 ? H0 : width_total;
  if (to_be_output) {
    output_line(to_be_output, to_be_output_width);
    hyphen_line_count = 0;
  }
  if (input_trap_count > 0) {
    if (--input_trap_count == 0)
      spring_trap(input_trap);
  }
}

void environment::output_line(node *n, hunits width)
{
  prev_text_length = width;
  if (margin_character_flags) {
    hunits d = line_length + margin_character_distance - saved_indent - width;
    if (d > 0) {
      n = new hmotion_node(d, n);
      width += d;
    }
    margin_character_flags &= ~MARGIN_CHARACTER_NEXT;
    node *tem;
    if (!margin_character_flags) {
      tem = margin_character_node;
      margin_character_node = 0;
    }
    else
      tem = margin_character_node->copy();
    tem->next = n;
    n = tem;
    width += tem->width();
  }
  node *nn = 0;
  while (n != 0) {
    node *tem = n->next;
    n->next = nn;
    nn = n;
    n = tem;
  }
  if (!saved_indent.is_zero())
    nn = new hmotion_node(saved_indent, nn);
  width += saved_indent;
  if (no_number_count > 0)
    --no_number_count;
  else if (numbering_nodes) {
    hunits w = (line_number_digit_width
		*(3+line_number_indent+number_text_separation));
    if (next_line_number % line_number_multiple != 0)
      nn = new hmotion_node(w, nn);
    else {
      hunits x = w;
      nn = new hmotion_node(number_text_separation*line_number_digit_width,
			    nn);
      x -= number_text_separation*line_number_digit_width;
      char buf[30];
      sprintf(buf, "%3d", next_line_number);
      for (char *p = strchr(buf, '\0') - 1; p >= buf && *p != ' '; --p) {
	node *gn = numbering_nodes;
	for (int count = *p - '0'; count > 0; count--)
	  gn = gn->next;
	gn = gn->copy();
	x -= gn->width();
	gn->next = nn;
	nn = gn;
      }
      nn = new hmotion_node(x, nn);
    }
    width += w;
    ++next_line_number;
  }
  output(nn, !fill, vertical_spacing, line_spacing, width);
}

void environment::start_line()
{
  assert(line == 0);
  discarding = 0;
  line = new line_start_node;
  if (have_temporary_indent) {
    saved_indent = temporary_indent;
    have_temporary_indent = 0;
  }
  else
    saved_indent = indent;
  target_text_length = line_length - saved_indent;
  width_total = H0;
  space_total = 0;
}

hunits environment::get_hyphenation_space()
{
  return hyphenation_space;
}

void hyphenation_space_request()
{
  hunits n;
  if (get_hunits(&n, 'm')) {
    if (n < H0) {
      warning(WARN_RANGE, "hyphenation space cannot be negative");
      n = H0;
    }
    curenv->hyphenation_space = n;
  }
  skip_line();
}

hunits environment::get_hyphenation_margin()
{
  return hyphenation_margin;
}

void hyphenation_margin_request()
{
  hunits n;
  if (get_hunits(&n, 'm')) {
    if (n < H0) {
      warning(WARN_RANGE, "hyphenation margin cannot be negative");
      n = H0;
    }
    curenv->hyphenation_margin = n;
  }
  skip_line();
}

breakpoint *environment::choose_breakpoint()
{
  hunits x = width_total;
  int s = space_total;
  node *n = line;
  breakpoint *best_bp = 0;	// the best breakpoint so far
  int best_bp_fits = 0;
  while (n != 0) {
    x -= n->width();
    s -= n->nspaces();
    breakpoint *bp = n->get_breakpoints(x, s);
    while (bp != 0) {
      if (bp->width <= target_text_length) {
	if (!bp->hyphenated) {
	  breakpoint *tem = bp->next;
	  bp->next = 0;
	  while (tem != 0) {
	    breakpoint *tem1 = tem;
	    tem = tem->next;
	    delete tem1;
	  }
	  if (best_bp_fits
	      // Decide whether to use the hyphenated breakpoint.
	      && (hyphen_line_max < 0
		  // Only choose the hyphenated breakpoint if it would not
		  // exceed the maximum number of consecutive hyphenated
		  // lines.
		  || hyphen_line_count + 1 <= hyphen_line_max)
	      && !(adjust_mode == ADJUST_BOTH
		   // Don't choose the hyphenated breakpoint if the line
		   // can be justified by adding no more than
		   // hyphenation_space to any word space.
		   ? (bp->nspaces > 0
		      && (((target_text_length - bp->width
			    + (bp->nspaces - 1)*hresolution)/bp->nspaces)
			  <= hyphenation_space))
		   // Don't choose the hyphenated breakpoint if the line
		   // is no more than hyphenation_margin short.
		   : target_text_length - bp->width <= hyphenation_margin)) {
	    delete bp;
	    return best_bp;
	  }
	  if (best_bp)
	    delete best_bp;
	  return bp;
	}
	else {
	  if ((adjust_mode == ADJUST_BOTH
	       ? hyphenation_space == H0
	       : hyphenation_margin == H0)
	      && (hyphen_line_max < 0
		  || hyphen_line_count + 1 <= hyphen_line_max)) {
	    // No need to consider a non-hyphenated breakpoint.
	    if (best_bp)
	      delete best_bp;
	    return bp;
	  }
	  // It fits but it's hyphenated.
	  if (!best_bp_fits) {
	    if (best_bp)
	      delete best_bp;
	    best_bp = bp;
	    bp = bp->next;
	    best_bp_fits = 1;
	  }
	  else {
	    breakpoint *tem = bp;
	    bp = bp->next;
	    delete tem;
	  }
	}
      }
      else {
	if (best_bp)
	  delete best_bp;
	best_bp = bp;
	bp = bp->next;
      }
    }
    n = n->next;
  }
  if (best_bp) {
    if (!best_bp_fits)
      warning(WARN_BREAK, "can't break line");
    return best_bp;
  }
  return 0;
}

void environment::hyphenate_line()
{
  if (line == 0)
    return;
  hyphenation_type prev_type = line->get_hyphenation_type();
  for (node **startp = &line->next; *startp != 0; startp = &(*startp)->next) {
    hyphenation_type this_type = (*startp)->get_hyphenation_type();
    if (prev_type == HYPHEN_BOUNDARY && this_type == HYPHEN_MIDDLE)
      break;
    prev_type = this_type;
  }
  if (*startp == 0)
    return;
  node *tem = *startp;
  int i = 0;
  do {
    ++i;
    tem = tem->next;
  } while (tem != 0 && tem->get_hyphenation_type() == HYPHEN_MIDDLE);
  int inhibit = (tem != 0 && tem->get_hyphenation_type() == HYPHEN_INHIBIT);
  node *end = tem;
  hyphen_list *sl = 0;
  tem = *startp;
  node *forward = 0;
  while (tem != end) {
    sl = tem->get_hyphen_list(sl);
    node *tem1 = tem;
    tem = tem->next;
    tem1->next = forward;
    forward = tem1;
  }
  if (!inhibit) {
    // this is for characters like hyphen and emdash
    int prev_code = 0;
    for (hyphen_list *h = sl; h; h = h->next) {
      h->breakable = (prev_code != 0
		      && h->next != 0
		      && h->next->hyphenation_code != 0);
      prev_code = h->hyphenation_code;
    }
  }
  if (hyphenation_flags != 0
      && !inhibit
      // this may not be right if we have extra space on this line
      && !((hyphenation_flags & HYPHEN_LAST_LINE)
	   && curdiv->distance_to_next_trap() <= line_spacing*vertical_spacing)
      && i >= 4)
    hyphenate(sl, hyphenation_flags);
  while (forward != 0) {
    node *tem1 = forward;
    forward = forward->next;
    tem1->next = 0;
    tem = tem1->add_self(tem, &sl);
  }
  *startp = tem;
}

static node *node_list_reverse(node *n)
{
  node *res = 0;
  while (n) {
    node *tem = n;
    n = n->next;
    tem->next = res;
    res = tem;
  }
  return res;
}

static void distribute_space(node *n, int nspaces, hunits desired_space,
			     int force_reverse = 0)
{
  static int reverse = 0;
  if (force_reverse || reverse)
    n = node_list_reverse(n);
  for (node *tem = n; tem; tem = tem->next)
    tem->spread_space(&nspaces, &desired_space);
  if (force_reverse || reverse)
    (void)node_list_reverse(n);
  if (!force_reverse)
    reverse = !reverse;
  assert(desired_space.is_zero() && nspaces == 0);
}

void environment::possibly_break_line(int forced)
{
  if (!fill || current_tab || current_field || dummy)
    return;
  while (line != 0 && (forced || width_total > target_text_length)) {
    hyphenate_line();
    breakpoint *bp = choose_breakpoint();
    if (bp == 0)
      // we'll find one eventually
      return;
    node *pre, *post;
    node **ndp = &line;
    while (*ndp != bp->nd)
      ndp = &(*ndp)->next;
    bp->nd->split(bp->index, &pre, &post);
    *ndp = post;
    hunits extra_space_width = H0;
    switch(adjust_mode) {
    case ADJUST_BOTH:
      if (bp->nspaces != 0)
	extra_space_width = target_text_length - bp->width;
      break;
    case ADJUST_CENTER:
      saved_indent += (target_text_length - bp->width)/2;
      break;
    case ADJUST_RIGHT:
      saved_indent += target_text_length - bp->width;
      break;
    }
    distribute_space(pre, bp->nspaces, extra_space_width);
    hunits output_width = bp->width + extra_space_width;
    input_line_start -= output_width;
    if (bp->hyphenated)
      hyphen_line_count++;
    else
      hyphen_line_count = 0;
    delete bp;
    space_total = 0;
    width_total = 0;
    node *first_non_discardable = 0;
    for (node *tem = line; tem != 0; tem = tem->next)
      if (!tem->discardable())
	first_non_discardable = tem;
    node *to_be_discarded;
    if (first_non_discardable) {
      to_be_discarded = first_non_discardable->next;
      first_non_discardable->next = 0;
      for (tem = line; tem != 0; tem = tem->next) {
	width_total += tem->width();
	space_total += tem->nspaces();
      }
      discarding = 0;
    }
    else {
      discarding = 1;
      to_be_discarded = line;
      line = 0;
    }
    // Do output_line() here so that line will be 0 iff the
    // the environment will be empty.
    output_line(pre, output_width);
    while (to_be_discarded != 0) {
      tem = to_be_discarded;
      to_be_discarded = to_be_discarded->next;
      input_line_start -= tem->width();
      delete tem;
    }
    if (line != 0) {
      if (have_temporary_indent) {
	saved_indent = temporary_indent;
	have_temporary_indent = 0;
      }
      else