env.cc

早期freebsd实现

  case TAB_NONE:
    return;
  case TAB_LEFT:
    add_node(make_tab_node(d));
    return;
  case TAB_RIGHT:
  case TAB_CENTER:
    tab_width = 0;
    tab_distance = d;
    tab_contents = 0;
    current_tab = t;
    tab_field_spaces = 0;
    return;
  default:
    assert(0);
  }
}

void environment::start_field()
{
  assert(!current_field);
  hunits d;
  if (distance_to_next_tab(&d) != TAB_NONE) {
    pre_field_width = get_text_length();
    field_distance = d;
    current_field = 1;
    field_spaces = 0;
    tab_field_spaces = 0;
    for (node *p = line; p; p = p->next)
      if (p->nspaces()) {
	p->freeze_space();
	space_total--;
      }
    tab_precedes_field = current_tab != TAB_NONE;
  }
  else
    error("zero field width");
}

void environment::wrap_up_field()
{
  if (!current_tab && field_spaces == 0)
    add_padding();
  hunits padding = field_distance - (get_text_length() - pre_field_width);
  if (current_tab && tab_field_spaces != 0) {
    hunits tab_padding = scale(padding, 
			       tab_field_spaces, 
			       field_spaces + tab_field_spaces);
    padding -= tab_padding;
    distribute_space(tab_contents, tab_field_spaces, tab_padding, 1);
    tab_field_spaces = 0;
    tab_width += tab_padding;
  }
  if (field_spaces != 0) {
    distribute_space(line, field_spaces, padding, 1);
    width_total += padding;
    if (current_tab) {
      // the start of the tab has been moved to the right by padding, so
      tab_distance -= padding;
      if (tab_distance <= H0) {
	// use the next tab stop instead
	current_tab = tabs.distance_to_next_tab(get_input_line_position()
						- tab_width,
						&tab_distance);
	if (current_tab == TAB_NONE || current_tab == TAB_LEFT) {
	  width_total += tab_width;
	  if (current_tab == TAB_LEFT) {
	    line = make_tab_node(tab_distance, line);
	    width_total += tab_distance;
	    current_tab = TAB_NONE;
	  }
	  if (tab_contents != 0) {
	    for (node *tem = tab_contents; tem->next != 0; tem = tem->next)
	      ;
	    tem->next = line;
	    line = tab_contents;
	    tab_contents = 0;
	  }
	  tab_width = H0;
	  tab_distance = H0;
	}
      }
    }
  }
  current_field = 0;
}

void environment::add_padding()
{
  if (current_tab) {
    tab_contents = new space_node(H0, tab_contents);
    tab_field_spaces++;
  }
  else {
    if (line == 0)
      start_line();
    line = new space_node(H0, line);
    field_spaces++;
  }
}

typedef int (environment::*INT_FUNCP)();
typedef vunits (environment::*VUNITS_FUNCP)();
typedef hunits (environment::*HUNITS_FUNCP)();
typedef const char *(environment::*STRING_FUNCP)();

class int_env_reg : public reg {
  INT_FUNCP func;
 public:
  int_env_reg(INT_FUNCP);
  const char *get_string();
  int get_value(units *val);
};

class vunits_env_reg : public reg {
  VUNITS_FUNCP func;
 public:
  vunits_env_reg(VUNITS_FUNCP f);
  const char *get_string();
  int get_value(units *val);
};


class hunits_env_reg : public reg {
  HUNITS_FUNCP func;
 public:
  hunits_env_reg(HUNITS_FUNCP f);
  const char *get_string();
  int get_value(units *val);
};

class string_env_reg : public reg {
  STRING_FUNCP func;
public:
  string_env_reg(STRING_FUNCP);
  const char *get_string();
};

int_env_reg::int_env_reg(INT_FUNCP f) : func(f)
{
}

int int_env_reg::get_value(units *val)
{
  *val = (curenv->*func)();
  return 1;
}

const char *int_env_reg::get_string()
{
  return itoa((curenv->*func)());
}
 
vunits_env_reg::vunits_env_reg(VUNITS_FUNCP f) : func(f)
{
}

int vunits_env_reg::get_value(units *val)
{
  *val = (curenv->*func)().to_units();
  return 1;
}

const char *vunits_env_reg::get_string()
{
  return itoa((curenv->*func)().to_units());
}

hunits_env_reg::hunits_env_reg(HUNITS_FUNCP f) : func(f)
{
}

int hunits_env_reg::get_value(units *val)
{
  *val = (curenv->*func)().to_units();
  return 1;
}

const char *hunits_env_reg::get_string()
{
  return itoa((curenv->*func)().to_units());
}

string_env_reg::string_env_reg(STRING_FUNCP f) : func(f)
{
}

const char *string_env_reg::get_string()
{
  return (curenv->*func)();
}

class horizontal_place_reg : public general_reg {
public:
  horizontal_place_reg();
  int get_value(units *);
  void set_value(units);
};

horizontal_place_reg::horizontal_place_reg()
{
}

int horizontal_place_reg::get_value(units *res)
{
  *res = curenv->get_input_line_position().to_units();
  return 1;
}

void horizontal_place_reg::set_value(units n)
{
  curenv->set_input_line_position(hunits(n));
}

const char *environment::get_font_family_string()
{
  return family->nm.contents();
}

const char *environment::get_name_string()
{
  return name.contents();
}

// Convert a quantity in scaled points to ascii decimal fraction.

const char *sptoa(int sp)
{
  assert(sp > 0);
  assert(sizescale > 0);
  if (sizescale == 1)
    return itoa(sp);
  if (sp % sizescale == 0)
    return itoa(sp/sizescale);
  // See if 1/sizescale is exactly representable as a decimal fraction,
  // ie its only prime factors are 2 and 5.
  int n = sizescale;
  int power2 = 0;
  while ((n & 1) == 0) {
    n >>= 1;
    power2++;
  }
  int power5 = 0;
  while ((n % 5) == 0) {
    n /= 5;
    power5++;
  }
  if (n == 1) {
    int decimal_point = power5 > power2 ? power5 : power2;
    if (decimal_point <= 10) {
      int factor = 1;
      int t;
      for (t = decimal_point - power2; --t >= 0;)
	factor *= 2;
      for (t = decimal_point - power5; --t >= 0;)
	factor *= 5;
      if (factor == 1 || sp <= INT_MAX/factor)
	return iftoa(sp*factor, decimal_point);
    }
  }
  double s = double(sp)/double(sizescale);
  double factor = 10.0;
  double val = s;
  int decimal_point = 0;
  do  {
    double v = ceil(s*factor);
    if (v > INT_MAX)
      break;
    val = v;
    factor *= 10.0;
  } while (++decimal_point < 10);
  return iftoa(int(val), decimal_point);
}

const char *environment::get_point_size_string()
{
  return sptoa(curenv->get_point_size());
}

const char *environment::get_requested_point_size_string()
{
  return sptoa(curenv->get_requested_point_size());
}

#define init_int_env_reg(name, func) \
  number_reg_dictionary.define(name, new int_env_reg(&environment::func))

#define init_vunits_env_reg(name, func) \
  number_reg_dictionary.define(name, new vunits_env_reg(&environment::func))

#define init_hunits_env_reg(name, func) \
  number_reg_dictionary.define(name, new hunits_env_reg(&environment::func))

#define init_string_env_reg(name, func) \
  number_reg_dictionary.define(name, new string_env_reg(&environment::func))

void init_env_requests()
{
  init_request("it", input_trap);
  init_request("ad", adjust);
  init_request("na", no_adjust);
  init_request("ev", environment_switch);
  init_request("lt", title_length);
  init_request("ps", point_size);
  init_request("ft", font_change);
  init_request("fam", family_change);
  init_request("ss", space_size);
  init_request("fi", fill);
  init_request("nf", no_fill);
  init_request("ce", center);
  init_request("rj", right_justify);
  init_request("vs", vertical_spacing);
  init_request("ls", line_spacing);
  init_request("ll", line_length);
  init_request("in", indent);
  init_request("ti", temporary_indent);
  init_request("ul", underline);
  init_request("cu", underline);
  init_request("cc", control_char);
  init_request("c2", no_break_control_char);
  init_request("br", break_request);
  init_request("tl", title);
  init_request("ta", set_tabs);
  init_request("fc", field_characters);
  init_request("mc", margin_character);
  init_request("nn", no_number);
  init_request("nm", number_lines);
  init_request("tc", tab_character);
  init_request("lc", leader_character);
  init_request("hy", hyphenate_request);
  init_request("hc", hyphen_char);
  init_request("nh", no_hyphenate);
  init_request("hlm", hyphen_line_max_request);
#ifdef WIDOW_CONTROL
  init_request("wdc", widow_control_request);
#endif /* WIDOW_CONTROL */
#if 0
  init_request("tas", tabs_save);
  init_request("tar", tabs_restore);
#endif  
  init_request("hys", hyphenation_space_request);
  init_request("hym", hyphenation_margin_request);
  init_int_env_reg(".f", get_font);
  init_int_env_reg(".b", get_bold);
  init_hunits_env_reg(".i", get_indent);
  init_hunits_env_reg(".in", get_saved_indent);
  init_int_env_reg(".j", get_adjust_mode);
  init_hunits_env_reg(".k", get_text_length);
  init_hunits_env_reg(".l", get_line_length);
  init_hunits_env_reg(".ll", get_saved_line_length);
  init_int_env_reg(".L", get_line_spacing);
  init_hunits_env_reg(".n", get_prev_text_length);
  init_string_env_reg(".s", get_point_size_string);
  init_string_env_reg(".sr", get_requested_point_size_string);
  init_int_env_reg(".ps", get_point_size);
  init_int_env_reg(".psr", get_requested_point_size);
  init_int_env_reg(".u", get_fill);
  init_vunits_env_reg(".v", get_vertical_spacing);
  init_hunits_env_reg(".w", get_prev_char_width);
  init_int_env_reg(".ss", get_space_size);
  init_int_env_reg(".sss", get_sentence_space_size);
  init_string_env_reg(".fam", get_font_family_string);
  init_string_env_reg(".ev", get_name_string);
  init_int_env_reg(".hy", get_hyphenation_flags);
  init_int_env_reg(".hlm", get_hyphen_line_max);
  init_int_env_reg(".hlc", get_hyphen_line_count);
  init_hunits_env_reg(".lt", get_title_length);
  init_string_env_reg(".tabs", get_tabs);
  init_hunits_env_reg(".csk", get_prev_char_skew);
  init_vunits_env_reg(".cht", get_prev_char_height);
  init_vunits_env_reg(".cdp", get_prev_char_depth);
  init_int_env_reg(".ce", get_center_lines);
  init_int_env_reg(".rj", get_right_justify_lines);
  init_hunits_env_reg(".hys", get_hyphenation_space);
  init_hunits_env_reg(".hym", get_hyphenation_margin);
  number_reg_dictionary.define("ln", new variable_reg(&next_line_number));
  number_reg_dictionary.define("ct", new variable_reg(&ct_reg_contents));
  number_reg_dictionary.define("sb", new variable_reg(&sb_reg_contents));
  number_reg_dictionary.define("st", new variable_reg(&st_reg_contents));
  number_reg_dictionary.define("rsb", new variable_reg(&rsb_reg_contents));
  number_reg_dictionary.define("rst", new variable_reg(&rst_reg_contents));
  number_reg_dictionary.define("ssc", new variable_reg(&ssc_reg_contents));
  number_reg_dictionary.define("skw", new variable_reg(&skw_reg_contents));
  number_reg_dictionary.define("hp", new horizontal_place_reg);
}

// Hyphenation - TeX's hyphenation algorithm with a less fancy implementation.

struct trie_node;

class trie {
  trie_node *tp;
  virtual void do_match(int len, void *val) = 0;
  virtual void do_delete(void *) = 0;
  void delete_trie_node(trie_node *);
public:
  trie() : tp(0) {}
  virtual ~trie();		// virtual to shut up g++
  void insert(const char *, int, void *);
  // find calls do_match for each match it finds
  void find(const char *pat, int patlen);
  void clear();
};

class hyphen_trie : private trie {
  int *h;
  void do_match(int i, void *v);
  void do_delete(void *v);
  void insert_pattern(const char *pat, int patlen, int *num);
public:
  hyphen_trie() {}
  ~hyphen_trie() {}
  void hyphenate(const char *word, int len, int *hyphens);
  void read_patterns_file(const char *name);
};


struct hyphenation_language {
  symbol name;
  dictionary exceptions;
  hyphen_trie patterns;
  hyphenation_language(symbol nm) : name(nm), exceptions(501) {}
  ~hyphenation_language() { }
};

dictionary language_dictionary(5);
hyphenation_language *current_language = 0;

static void set_hyphenation_language()
{
  symbol nm = get_name(1);
  if (!nm.is_null()) {
    current_language = (hyphenation_language *)language_dictionary.lookup(nm);
    if (!current_language) {
      current_language = new hyphenation_language(nm);
      (void)language_dictionary.lookup(nm, (void *)current_language);
    }
  }
  skip_line();
}

const int WORD_MAX = 1024;

static void hyphen_word()
{
  if (!current_language) {
    error("no current hyphenation language");
    skip_line();
    return;
  }
  char buf[WORD_MAX + 1];
  unsigned char pos[WORD_MAX + 2];
  for (;;) {
    tok.skip();
    if (tok.newline() || tok.eof())
      break;
    int i = 0;
    int npos = 0;
    while (i < WORD_MAX && !tok.space() && !tok.newline() && !tok.eof()) {
      charinfo *ci = tok.get_char(1);
      if (ci == 0) {
	skip_line();
	return;
      }
      tok.next();
      if (ci->get_ascii_code() == '-') {
	if (i > 0 && (npos == 0 || pos[npos - 1] != i))
	  pos[npos++] = i;
      }
      else {
	int c = ci->get_hyphenation_code();
	if (c == 0)
	  break;
	buf[i++] = c;
      }
    }
    if (i > 0) {
      pos[npos] = 0;
      buf[i] = 0;
      unsigned char *tem = new unsigned char[npos + 1];
      memcpy(tem, pos, npos+1);
      tem = (unsigned char *)current_language->exceptions.lookup(symbol(buf),
								 tem);
      if (tem)
	a_delete tem;
    }
  }
  skip_line();
}

struct trie_node {
  char c;
  trie_node *down;
  trie_node *right;
  void *val;
  trie_node(char, trie_node *);
};

trie_node::trie_node(char ch, trie_node *p) 
: c(ch), right(p), down(0), val(0)
{
}

trie::~trie()
{
  clear();
}

void trie::clear()
{
  delete_trie_node(tp);
  tp = 0;
}


void trie::delete_trie_node(trie_node *p)
{
  if (p) {
    delete_trie_node(p->down);
    delete_trie_node(p->right);
    if (p->val)
      do_delete(p->val);
    delete p;
  }
}

void trie::insert(const char *pat, int patlen, void *val)
{
  trie_node **p = &tp;
  assert(patlen > 0 && pat != 0);
  for (;;) {
    while (*p != 0 && (*p)->c < pat[0])
      p = &((*p)->right);
    if (*p == 0 || (*p)->c != pat[0])
      *p = new trie_node(pat[0], *p);
    if (--patlen == 0) {
      (*p)->val = val;
      break;
    }
    ++pat;
    p = &((*p)->down);
  }
}

void trie::find(const char *pat, int patlen)
{
  trie_node *p = tp;
  for (int i = 0; p != 0 && i < patlen; i++) {
    while (p != 0 && p->c < pat[i])
      p = p->right;
    if (p != 0 && p->c == pat[i]) {
      if (p->val != 0)
	do_match(i+1, p->val);
      p = p->down;
    }
    else
      break;
  }
}

struct operation {
  operation *next;
  short distance;
  short num;
  operation(int, int, operation *);
};

operation::operation(int i, int j, operation *op)
: num(i), distance(j), next(op)
{
}

void hyphen_trie::insert_pattern(const char *pat, int patlen, int *num)
{
  operation *op = 0;
  for (int i = 0; i < patlen+1; i++)
    if