div.cc

早期freebsd实现

// -*- C++ -*-
/* Copyright (C) 1989, 1990, 1991, 1992 Free Software Foundation, Inc.
     Written by James Clark ([e-mail])

This file is part of groff.

groff 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 2, or (at your option) any later
version.

groff 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 groff; see the file COPYING.  If not, write to the Free Software
Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */


// diversions

#include "troff.h"
#include "symbol.h"
#include "dictionary.h"
#include "hvunits.h"
#include "env.h"
#include "request.h"
#include "node.h"
#include "token.h"
#include "div.h"
#include "reg.h"

int exit_started = 0;		// the exit process has started
int done_end_macro = 0;		// the end macro (if any) has finished
int seen_last_page_ejector = 0;	// seen the LAST_PAGE_EJECTOR cookie
static int began_page_in_end_macro = 0;	// a new page was begun during the end macro

static int last_post_line_extra_space = 0; // needed for \n(.a
static int nl_reg_contents = -1;
static int dl_reg_contents = 0;
static int dn_reg_contents = 0;
static int vertical_position_traps_flag = 1;
static vunits truncated_space;
static vunits needed_space;

diversion::diversion(symbol s) 
: nm(s), prev(0), vertical_position(V0), marked_place(V0), high_water_mark(V0)
{
}

struct vertical_size {
  vunits pre_extra, post_extra, pre, post;
  vertical_size(vunits vs, int ls);
};

vertical_size::vertical_size(vunits vs, int ls)
: pre_extra(V0), post_extra(V0), pre(vs)
{
  if (ls > 1)
    post = vs*(ls - 1);
  else
    post = V0;
}

void node::set_vertical_size(vertical_size *)
{
}

void extra_size_node::set_vertical_size(vertical_size *v)
{
  if (n < V0) {
    if (-n > v->pre_extra)
      v->pre_extra = -n;
  }
  else if (n > v->post_extra)
    v->post_extra = n;
}

void vertical_size_node::set_vertical_size(vertical_size *v)
{
  if (n < V0)
    v->pre = -n;
  else
    v->post = n;
}

top_level_diversion *topdiv;

diversion *curdiv;

void do_divert(int append)
{
  tok.skip();
  symbol nm = get_name();
  if (nm.is_null()) {
    if (curdiv->prev) {
      diversion *temp = curdiv;
      curdiv = curdiv->prev;
      delete temp;
    }
    else
      warning(WARN_DI, "diversion stack underflow");
  }
  else {
    macro_diversion *md = new macro_diversion(nm, append);
    md->prev = curdiv;
    curdiv = md;
  }
  skip_line();
}

void divert()
{
  do_divert(0);
}

void divert_append()
{
  do_divert(1);
}
  
void diversion::need(vunits n)
{
  vunits d = distance_to_next_trap();
  if (d < n) {
    space(d, 1);
    truncated_space = -d;
    needed_space = n;
  }
}

macro_diversion::macro_diversion(symbol s, int append)
: diversion(s), max_width(H0)
{
#if 0
  if (append) {
    /* We don't allow recursive appends eg:

      .da a
      .a
      .di
      
      This causes an infinite loop in troff anyway.
      This is because the user could do

      .as a foo

      in the diversion, and this would mess things up royally,
      since there would be two things appending to the same
      macro_header.
      To make it work, we would have to copy the _contents_
      of the macro into which we were diverting; this doesn't
      strike me as worthwhile.
      However,

      .di a
      .a
      .a
      .di

       will work and will make `a' contain two copies of what it contained
       before; in troff, `a' would contain nothing. */
    request_or_macro *rm 
      = (request_or_macro *)request_dictionary.remove(s);
    if (!rm || (mac = rm->to_macro()) == 0)
      mac = new macro;
  }
  else
    mac = new macro;
#endif
  // We can now catch the situation described above by comparing
  // the length of the charlist in the macro_header with the length
  // stored in the macro. When we detect this, we copy the contents.
  mac = new macro;
  if (append) {
    request_or_macro *rm 
      = (request_or_macro *)request_dictionary.lookup(s);
    if (rm) {
      macro *m = rm->to_macro();
      if (m)
	*mac = *m;
    }
  }
}

macro_diversion::~macro_diversion()
{
  request_or_macro *rm = (request_or_macro *)request_dictionary.lookup(nm);
  macro *m = rm ? rm->to_macro() : 0;
  if (m) {
    *m = *mac;
    delete mac;
  }
  else
    request_dictionary.define(nm, mac);
  mac = 0;
  dl_reg_contents = max_width.to_units();
  dn_reg_contents = vertical_position.to_units();
}

vunits macro_diversion::distance_to_next_trap()
{
  if (!diversion_trap.is_null() && diversion_trap_pos > vertical_position)
    return diversion_trap_pos - vertical_position;
  else
    // Substract vresolution so that vunits::vunits does not overflow.
    return vunits(INT_MAX - vresolution);
}

void macro_diversion::transparent_output(unsigned char c)
{
  mac->append(c);
}

void macro_diversion::transparent_output(node *n)
{
  mac->append(n);
}

void macro_diversion::output(node *nd, int retain_size,
			     vunits vs, int ls, hunits width)
{
  vertical_size v(vs, ls);
  while (nd != 0) {
    nd->set_vertical_size(&v);
    node *temp = nd;
    nd = nd->next;
    if (temp->interpret(mac)) {
      delete temp;
    }
    else {
#if 1
      temp->freeze_space();
#endif
      mac->append(temp);
    }
  }
  if (!v.post_extra.is_zero())
    last_post_line_extra_space = v.post_extra.to_units();
  if (!retain_size) {
    v.pre = vs;
    v.post = (ls > 1) ? vs*(ls - 1) : V0;
  }
  if (width > max_width)
    max_width = width;
  vunits x = v.pre + v.pre_extra + v.post + v.post_extra;
  if (vertical_position_traps_flag
      && !diversion_trap.is_null() && diversion_trap_pos > vertical_position
      && diversion_trap_pos <= vertical_position + x) {
    vunits trunc = vertical_position + x - diversion_trap_pos;
    if (trunc > v.post)
      trunc = v.post;
    v.post -= trunc;
    x -= trunc;
    truncated_space = trunc;
    spring_trap(diversion_trap);
  }
  mac->append(new vertical_size_node(-v.pre));
  mac->append(new vertical_size_node(v.post));
  mac->append('\n');
  vertical_position += x;
  if (vertical_position - v.post > high_water_mark)
    high_water_mark = vertical_position - v.post;
}

void macro_diversion::space(vunits n, int)
{
  if (vertical_position_traps_flag
      && !diversion_trap.is_null() && diversion_trap_pos > vertical_position
      && diversion_trap_pos <= vertical_position + n) {
    truncated_space = vertical_position + n - diversion_trap_pos;
    n = diversion_trap_pos - vertical_position;
    spring_trap(diversion_trap);
  }
  else if (n + vertical_position < V0)
    n = -vertical_position;
  mac->append(new diverted_space_node(n));
  vertical_position += n;
}

void macro_diversion::copy_file(const char *filename)
{
  mac->append(new diverted_copy_file_node(filename));
}

top_level_diversion::top_level_diversion()
: page_count(0), have_next_page_number(0), page_length(units_per_inch*11), 
  page_offset(units_per_inch), prev_page_offset(units_per_inch), 
  ejecting_page(0), page_trap_list(0), before_first_page(1), no_space_mode(0),
  page_number(0), last_page_count(-1)
{
}

// find the next trap after pos

trap *top_level_diversion::find_next_trap(vunits *next_trap_pos)
{
  trap *next_trap = 0;
  for (trap *pt = page_trap_list; pt != 0; pt = pt->next)
    if (!pt->nm.is_null()) {
      if (pt->position >= V0) {
	if (pt->position > vertical_position 
	    && pt->position < page_length
	    && (next_trap == 0 || pt->position < *next_trap_pos)) {
	      next_trap = pt;
	      *next_trap_pos = pt->position;
	    }
      }
      else {
	vunits pos = pt->position;
	pos += page_length;
	if (pos > 0 && pos > vertical_position && (next_trap == 0 || pos < *next_trap_pos)) {
	  next_trap = pt;
	  *next_trap_pos = pos;
	}
      }
    }
  return next_trap;
}

vunits top_level_diversion::distance_to_next_trap()
{
  vunits d;
  if (!find_next_trap(&d))
    return page_length - vertical_position;
  else
    return d - vertical_position;
}

void top_level_diversion::output(node *nd, int retain_size,
				 vunits vs, int ls, hunits /*width*/)
{
  no_space_mode = 0;
  vunits next_trap_pos;
  trap *next_trap = find_next_trap(&next_trap_pos);
  if (before_first_page && begin_page()) 
    fatal("sorry, I didn't manage to begin the first page in time: use an explicit .br request");
  vertical_size v(vs, ls);
  for (node *tem = nd; tem != 0; tem = tem->next)
    tem->set_vertical_size(&v);
  if (!v.post_extra.is_zero())
    last_post_line_extra_space = v.post_extra.to_units();
  if (!retain_size) {
    v.pre = vs;
    v.post = (ls > 1) ? vs*(ls - 1) : V0;
  }
  vertical_position += v.pre;
  vertical_position += v.pre_extra;
  the_output->print_line(page_offset, vertical_position, nd,
			 v.pre + v.pre_extra, v.post_extra);
  vertical_position += v.post_extra;
  if (vertical_position > high_water_mark)
    high_water_mark = vertical_position;
  if (vertical_position_traps_flag && vertical_position >= page_length)
    begin_page();
  else if (vertical_position_traps_flag
	   && next_trap != 0 && vertical_position >= next_trap_pos) {
    nl_reg_contents = vertical_position.to_units();
    truncated_space = v.post;
    spring_trap(next_trap->nm);
  }
  else if (v.post > V0) {
    vertical_position += v.post;
    if (vertical_position_traps_flag
	&& next_trap != 0 && vertical_position >= next_trap_pos) {
      truncated_space = vertical_position - next_trap_pos;
      vertical_position = next_trap_pos;
      nl_reg_contents = vertical_position.to_units();
      spring_trap(next_trap->nm);
    }
    else if (vertical_position_traps_flag && vertical_position >= page_length)
      begin_page();
    else
      nl_reg_contents = vertical_position.to_units();
  }
  else
    nl_reg_contents = vertical_position.to_units();
}

void top_level_diversion::transparent_output(unsigned char c)
{
  if (before_first_page && begin_page())
    // This can only happen with the transparent() request.
    fatal("sorry, I didn't manage to begin the first page in time: use an explicit .br request");
  const char *s = asciify(c);
  while (*s)
    the_output->transparent_char(*s++);
}

void top_level_diversion::transparent_output(node * /*n*/)
{
  error("can't transparently output node at top level");
}

void top_level_diversion::copy_file(const char *filename)
{
  if (before_first_page && begin_page())
    fatal("sorry, I didn't manage to begin the first page in time: use an explicit .br request");
  the_output->copy_file(page_offset, vertical_position, filename);
}

void top_level_diversion::space(vunits n, int forced)
{
  if (no_space_mode) {
    if (!forced)
      return;
    else
      no_space_mode = 0;
  }
  if (before_first_page) {
    if (begin_page()) {
      // This happens if there's a top of page trap, and the first-page
      // transition is caused by `'sp'.
      truncated_space = n > V0 ? n : V0;
      return;
    }
  }
  vunits next_trap_pos;
  trap *next_trap = find_next_trap(&next_trap_pos);
  vunits y = vertical_position + n;
  if (vertical_position_traps_flag && next_trap != 0 && y >= next_trap_pos) {
    vertical_position = next_trap_pos;
    nl_reg_contents = vertical_position.to_units();
    truncated_space = y - vertical_position;
    spring_trap(next_trap->nm);
  }
  else if (y < V0) {
    vertical_position = V0;
    nl_reg_contents = vertical_position.to_units();
  }
  else if (vertical_position_traps_flag && y >= page_length && n >= V0)
    begin_page();
  else {
    vertical_position = y;
    nl_reg_contents = vertical_position.to_units();
  }
}

trap::trap(symbol s, vunits n, trap *p)
     : nm(s), next(p), position(n)
{
}

void top_level_diversion::add_trap(symbol nm, vunits pos)
{
  trap *first_free_slot = 0;
  for (trap **p = &page_trap_list; *p; p = &(*p)->next) {
    if ((*p)->nm.is_null()) {
      if (first_free_slot == 0)
	first_free_slot = *p;
    }
    else if ((*p)->position == pos) {
      (*p)->nm = nm;
      return;
    }
  }
  if (first_free_slot) {
    first_free_slot->nm = nm;
    first_free_slot->position = pos;
  }
  else
    *p = new trap(nm, pos, 0);
}  

void top_level_diversion::remove_trap(symbol nm)
{
  for (trap *p = page_trap_list; p; p = p->next)
    if (p->nm == nm) {
      p->nm = NULL_SYMBOL;
      return;
    }
}

void top_level_diversion::remove_trap_at(vunits pos)
{
  for (trap *p = page_trap_list; p; p = p->next)
    if (p->position == pos) {
      p->nm = NULL_SYMBOL;
      return;
    }
}
      
void top_level_diversion::change_trap(symbol nm, vunits pos)
{
  for (trap *p = page_trap_list; p; p = p->next)
    if (p->nm == nm) {
      p->position = pos;
      return;
    }
}

void top_level_diversion::print_traps()
{
  for (trap *p = page_trap_list; p; p = p->next)
    if (p->nm.is_null())
      fprintf(stderr, "  empty\n");
    else
      fprintf(stderr, "%s\t%d\n", p->nm.contents(), p->position.to_units());
  fflush(stderr);
}

void end_diversions()
{
  while (curdiv != topdiv) {
    error("automatically ending diversion `%1' on exit",
	    curdiv->nm.contents());
    diversion *tem = curdiv;
    curdiv = curdiv->prev;
    delete tem;
  }
}

NO_RETURN void cleanup_and_exit(int exit_code)
{
  if (the_output) {
    the_output->trailer(topdiv->get_page_length());
    delete the_output;
  }
  exit(exit_code);
}

// returns non-zero if it sprung a top of page trap

int top_level_diversion::begin_page()
{
  if (exit_started) {
    if (page_count == last_page_count
	? curenv->is_empty()
	: (done_end_macro && (seen_last_page_ejector || began_page_in_end_macro)))
      cleanup_and_exit(0);
    if (!done_end_macro)
      began_page_in_end_macro = 1;
  }
  if (!the_output)
    init_output();
  ++page_count;
  if (have_next_page_number) {
    page_number = next_page_number;
    have_next_page_number = 0;
  }
  else if (before_first_page == 1)
    page_number = 1;
  else
    page_number++;
  // spring the top of page trap if there is one
  vunits next_trap_pos;
  vertical_position = -vresolution;
  trap *next_trap = find_next_trap(&next_trap_pos);
  vertical_position = V0;
  high_water_mark = V0;
  ejecting_page = 0;
  // If before_first_page was 2, then the top of page transition was undone
  // using eg .nr nl 0-1.  See nl_reg::set_value.
  if (before_first_page != 2)
    the_output->begin_page(page_number, page_length);
  before_first_page = 0;
  nl_reg_contents = vertical_position.to_units();
  if (vertical_position_traps_flag && next_trap != 0 && next_trap_pos == V0) {
    truncated_space = V0;
    spring_trap(next_trap->nm);
    return 1;