groff: update vendor branch to v1.20.1

[dragonfly.git] / contrib / groff / src / libs / libgroff / font.cpp

// -*- C++ -*-
/* Copyright (C) 1989, 1990, 1991, 1992, 2000, 2001, 2002, 2003, 2004, 2005,
                 2006, 2008, 2009
   Free Software Foundation, Inc.
     Written by James Clark (jjc@jclark.com)

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 3 of the License, 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 this program. If not, see <http://www.gnu.org/licenses/>. */

#include "lib.h"

#include <ctype.h>
#include <assert.h>
#include <math.h>
#include <stdlib.h>
#include "errarg.h"
#include "error.h"
#include "cset.h"
#include "font.h"
#include "unicode.h"
#include "paper.h"

const char *const WS = " \t\n\r";

struct font_char_metric {
  char type;
  int code;
  int width;
  int height;
  int depth;
  int pre_math_space;
  int italic_correction;
  int subscript_correction;
  char *special_device_coding;
};

struct font_kern_list {
  glyph *glyph1;
  glyph *glyph2;
  int amount;
  font_kern_list *next;

  font_kern_list(glyph *, glyph *, int, font_kern_list * = 0);
};

struct font_widths_cache {
  font_widths_cache *next;
  int point_size;
  int *width;

  font_widths_cache(int, int, font_widths_cache * = 0);
  ~font_widths_cache();
};

/* text_file */

struct text_file {
  FILE *fp;
  char *path;
  int lineno;
  int size;
  int skip_comments;
  int silent;
  char *buf;
  text_file(FILE *fp, char *p);
  ~text_file();
  int next();
  void error(const char *format, 
	     const errarg &arg1 = empty_errarg,
	     const errarg &arg2 = empty_errarg,
	     const errarg &arg3 = empty_errarg);
};

text_file::text_file(FILE *p, char *s) 
: fp(p), path(s), lineno(0), size(0), skip_comments(1), silent(0), buf(0)
{
}

text_file::~text_file()
{
  a_delete buf;
  a_delete path;
  if (fp)
    fclose(fp);
}

int text_file::next()
{
  if (fp == 0)
    return 0;
  if (buf == 0) {
    buf = new char[128];
    size = 128;
  }
  for (;;) {
    int i = 0;
    for (;;) {
      int c = getc(fp);
      if (c == EOF)
	break;
      if (invalid_input_char(c))
	error("invalid input character code `%1'", int(c));
      else {
	if (i + 1 >= size) {
	  char *old_buf = buf;
	  buf = new char[size*2];
	  memcpy(buf, old_buf, size);
	  a_delete old_buf;
	  size *= 2;
	}
	buf[i++] = c;
	if (c == '\n')
	  break;
      }
    }
    if (i == 0)
      break;
    buf[i] = '\0';
    lineno++;
    char *ptr = buf;
    while (csspace(*ptr))
      ptr++;
    if (*ptr != 0 && (!skip_comments || *ptr != '#'))
      return 1;
  }
  return 0;
}

void text_file::error(const char *format, 
		      const errarg &arg1,
		      const errarg &arg2,
		      const errarg &arg3)
{
  if (!silent)
    error_with_file_and_line(path, lineno, format, arg1, arg2, arg3);
}


/* font functions */

font::font(const char *s)
: ligatures(0), kern_hash_table(0), space_width(0), special(0),
  ch_index(0), nindices(0), ch(0), ch_used(0), ch_size(0), widths_cache(0)
{
  name = new char[strlen(s) + 1];
  strcpy(name, s);
  internalname = 0;
  slant = 0.0;
  zoom = 0;
  // load();			// for testing
}

font::~font()
{
  for (int i = 0; i < ch_used; i++)
    if (ch[i].special_device_coding)
      a_delete ch[i].special_device_coding;
  a_delete ch;
  a_delete ch_index;
  if (kern_hash_table) {
    for (int i = 0; i < KERN_HASH_TABLE_SIZE; i++) {
      font_kern_list *kerns = kern_hash_table[i];
      while (kerns) {
	font_kern_list *tem = kerns;
	kerns = kerns->next;
	delete tem;
      }
    }
    a_delete kern_hash_table;
  }
  a_delete name;
  a_delete internalname;
  while (widths_cache) {
    font_widths_cache *tem = widths_cache;
    widths_cache = widths_cache->next;
    delete tem;
  }
}

static int scale_round(int n, int x, int y)
{
  assert(x >= 0 && y > 0);
  int y2 = y/2;
  if (x == 0)
    return 0;
  if (n >= 0) {
    if (n <= (INT_MAX - y2) / x)
      return (n * x + y2) / y;
    return int(n * double(x) / double(y) + .5);
  }
  else {
    if (-(unsigned)n <= (-(unsigned)INT_MIN - y2) / x)
      return (n * x - y2) / y;
    return int(n * double(x) / double(y) - .5);
  }
}

static int scale_round(int n, int x, int y, int z)
{
  assert(x >= 0 && y > 0 && z > 0);
  if (x == 0)
    return 0;
  if (n >= 0)
    return int((n * double(x) / double(y)) * (double(z) / 1000.0) + .5);
  else
    return int((n * double(x) / double(y)) * (double(z) / 1000.0) - .5);
}

inline int font::scale(int w, int sz)
{
  if (zoom)
    return scale_round(w, sz, unitwidth, zoom);
  else
    return sz == unitwidth ? w : scale_round(w, sz, unitwidth);
}

int font::unit_scale(double *value, char unit)
{
  // we scale everything to inch
  double divisor = 0;
  switch (unit) {
  case 'i':
    divisor = 1;
    break;
  case 'p':
    divisor = 72;
    break;
  case 'P':
    divisor = 6;
    break;
  case 'c':
    divisor = 2.54;
    break;
  default:
    assert(0);
    break;
  }
  if (divisor) {
    *value /= divisor;
    return 1;
  }
  return 0;
}

int font::get_skew(glyph *g, int point_size, int sl)
{
  int h = get_height(g, point_size);
  return int(h * tan((slant + sl) * PI / 180.0) + .5);
}

int font::contains(glyph *g)
{
  int idx = glyph_to_index(g);
  assert(idx >= 0);
  // Explicitly enumerated glyph?
  if (idx < nindices && ch_index[idx] >= 0)
    return 1;
  if (is_unicode) {
    // Unicode font
    const char *nm = glyph_to_name(g);
    if (nm != NULL) {
      // ASCII character?
      if (nm[0] == 'c' && nm[1] == 'h' && nm[2] == 'a' && nm[3] == 'r'
          && (nm[4] >= '0' && nm[4] <= '9')) {
	int n = (nm[4] - '0');
	if (nm[5] == '\0')
	  return 1;
	if (n > 0 && (nm[5] >= '0' && nm[5] <= '9')) {
	  n = 10*n + (nm[5] - '0');
	  if (nm[6] == '\0')
	    return 1;
	  if (nm[6] >= '0' && nm[6] <= '9') {
	    n = 10*n + (nm[6] - '0');
	    if (nm[7] == '\0' && n < 128)
	      return 1;
	  }
	}
      }
      // Unicode character?
      if (check_unicode_name(nm))
	return 1;
      // If `nm' is a single letter `x', the glyph name is `\x'.
      char buf[] = { '\\', '\0', '\0' };
      if (nm[1] == '\0') {
	buf[1] = nm[0];
        nm = buf;
      }
      // groff glyph name that maps to Unicode?
      const char *unicode = glyph_name_to_unicode(nm);
      if (unicode != NULL && strchr(unicode, '_') == NULL)
	return 1;
    }
    // Numbered character?
    int n = glyph_to_number(g);
    if (n >= 0)
      return 1;
  }
  return 0;
}

int font::is_special()
{
  return special;
}

font_widths_cache::font_widths_cache(int ps, int ch_size,
				     font_widths_cache *p)
: next(p), point_size(ps)
{
  width = new int[ch_size];
  for (int i = 0; i < ch_size; i++)
    width[i] = -1;
}

font_widths_cache::~font_widths_cache()
{
  a_delete width;
}

int font::get_width(glyph *g, int point_size)
{
  int idx = glyph_to_index(g);
  assert(idx >= 0);
  int real_size;
  if (!zoom)
    real_size = point_size;
  else
  {
    if (point_size <= (INT_MAX - 500) / zoom)
      real_size = (point_size * zoom + 500) / 1000;
    else
      real_size = int(point_size * double(zoom) / 1000.0 + .5);
  }
  if (idx < nindices && ch_index[idx] >= 0) {
    // Explicitly enumerated glyph
    int i = ch_index[idx];
    if (real_size == unitwidth || font::unscaled_charwidths)
      return ch[i].width;

    if (!widths_cache)
      widths_cache = new font_widths_cache(real_size, ch_size);
    else if (widths_cache->point_size != real_size) {
      font_widths_cache **p;
      for (p = &widths_cache; *p; p = &(*p)->next)
	if ((*p)->point_size == real_size)
	  break;
      if (*p) {
	font_widths_cache *tem = *p;
	*p = (*p)->next;
	tem->next = widths_cache;
	widths_cache = tem;
      }
      else
	widths_cache = new font_widths_cache(real_size, ch_size,
					     widths_cache);
    }
    int &w = widths_cache->width[i];
    if (w < 0)
      w = scale(ch[i].width, point_size);
    return w;
  }
  if (is_unicode) {
    // Unicode font
    int width = 24;	// value found in the original font files
			// XXX: this must be eventually moved back to the
			//      font description file!
    if (real_size == unitwidth || font::unscaled_charwidths)
      return width;
    else
      return scale(width, point_size);
  }
  abort();
}

int font::get_height(glyph *g, int point_size)
{
  int idx = glyph_to_index(g);
  assert(idx >= 0);
  if (idx < nindices && ch_index[idx] >= 0) {
    // Explicitly enumerated glyph
    return scale(ch[ch_index[idx]].height, point_size);
  }
  if (is_unicode) {
    // Unicode font
    return 0;	// value found in the original font files
		// XXX: this must be eventually moved back to the
		//      font description file!
  }
  abort();
}

int font::get_depth(glyph *g, int point_size)
{
  int idx = glyph_to_index(g);
  assert(idx >= 0);
  if (idx < nindices && ch_index[idx] >= 0) {
    // Explicitly enumerated glyph
    return scale(ch[ch_index[idx]].depth, point_size);
  }
  if (is_unicode) {
    // Unicode font
    return 0;	// value found in the original font files
		// XXX: this must be eventually moved back to the
		//      font description file!
  }
  abort();
}

int font::get_italic_correction(glyph *g, int point_size)
{
  int idx = glyph_to_index(g);
  assert(idx >= 0);
  if (idx < nindices && ch_index[idx] >= 0) {
    // Explicitly enumerated glyph
    return scale(ch[ch_index[idx]].italic_correction, point_size);
  }
  if (is_unicode) {
    // Unicode font
    return 0;	// value found in the original font files
		// XXX: this must be eventually moved back to the
		//      font description file!
  }
  abort();
}

int font::get_left_italic_correction(glyph *g, int point_size)
{
  int idx = glyph_to_index(g);
  assert(idx >= 0);
  if (idx < nindices && ch_index[idx] >= 0) {
    // Explicitly enumerated glyph
    return scale(ch[ch_index[idx]].pre_math_space, point_size);
  }
  if (is_unicode) {
    // Unicode font
    return 0;	// value found in the original font files
		// XXX: this must be eventually moved back to the
		//      font description file!
  }
  abort();
}

int font::get_subscript_correction(glyph *g, int point_size)
{
  int idx = glyph_to_index(g);
  assert(idx >= 0);
  if (idx < nindices && ch_index[idx] >= 0) {
    // Explicitly enumerated glyph
    return scale(ch[ch_index[idx]].subscript_correction, point_size);
  }
  if (is_unicode) {
    // Unicode font
    return 0;	// value found in the original font files
		// XXX: this must be eventually moved back to the
		//      font description file!
  }
  abort();
}

void font::set_zoom(int factor)
{
  assert(factor >= 0);
  if (factor == 1000)
    zoom = 0;
  else
    zoom = factor;
}

int font::get_zoom()
{
  return zoom;
}

int font::get_space_width(int point_size)
{
  return scale(space_width, point_size);
}

font_kern_list::font_kern_list(glyph *g1, glyph *g2, int n, font_kern_list *p)
: glyph1(g1), glyph2(g2), amount(n), next(p)
{
}

inline int font::hash_kern(glyph *g1, glyph *g2)
{
  int n = ((glyph_to_index(g1) << 10) + glyph_to_index(g2))
	  % KERN_HASH_TABLE_SIZE;
  return n < 0 ? -n : n;
}

void font::add_kern(glyph *g1, glyph *g2, int amount)
{
  if (!kern_hash_table) {
    kern_hash_table = new font_kern_list *[int(KERN_HASH_TABLE_SIZE)];
    for (int i = 0; i < KERN_HASH_TABLE_SIZE; i++)
      kern_hash_table[i] = 0;
  }
  font_kern_list **p = kern_hash_table + hash_kern(g1, g2);
  *p = new font_kern_list(g1, g2, amount, *p);
}

int font::get_kern(glyph *g1, glyph *g2, int point_size)
{
  if (kern_hash_table) {
    for (font_kern_list *p = kern_hash_table[hash_kern(g1, g2)]; p;
	 p = p->next)
      if (g1 == p->glyph1 && g2 == p->glyph2)
	return scale(p->amount, point_size);
  }
  return 0;
}

int font::has_ligature(int mask)
{
  return mask & ligatures;
}

int font::get_character_type(glyph *g)
{
  int idx = glyph_to_index(g);
  assert(idx >= 0);
  if (idx < nindices && ch_index[idx] >= 0) {
    // Explicitly enumerated glyph
    return ch[ch_index[idx]].type;
  }
  if (is_unicode) {
    // Unicode font
    return 0;	// value found in the original font files
		// XXX: this must be eventually moved back to the
		//      font description file!
  }
  abort();
}

int font::get_code(glyph *g)
{
  int idx = glyph_to_index(g);
  assert(idx >= 0);
  if (idx < nindices && ch_index[idx] >= 0) {
    // Explicitly enumerated glyph
    return ch[ch_index[idx]].code;
  }
  if (is_unicode) {
    // Unicode font
    const char *nm = glyph_to_name(g);
    if (nm != NULL) {
      // ASCII character?
      if (nm[0] == 'c' && nm[1] == 'h' && nm[2] == 'a' && nm[3] == 'r'
          && (nm[4] >= '0' && nm[4] <= '9')) {
	int n = (nm[4] - '0');
	if (nm[5] == '\0')
	  return n;
	if (n > 0 && (nm[5] >= '0' && nm[5] <= '9')) {
	  n = 10*n + (nm[5] - '0');
	  if (nm[6] == '\0')
	    return n;
	  if (nm[6] >= '0' && nm[6] <= '9') {
	    n = 10*n + (nm[6] - '0');
	    if (nm[7] == '\0' && n < 128)
	      return n;
	  }
	}
      }
      // Unicode character?
      if (check_unicode_name(nm)) {
	char *ignore;
	return (int)strtol(nm + 1, &ignore, 16);
      }
      // If `nm' is a single letter `x', the glyph name is `\x'.
      char buf[] = { '\\', '\0', '\0' };
      if (nm[1] == '\0') {
	buf[1] = nm[0];
        nm = buf;
      }
      // groff glyphs that map to Unicode?
      const char *unicode = glyph_name_to_unicode(nm);
      if (unicode != NULL && strchr(unicode, '_') == NULL) {
	char *ignore;
	return (int)strtol(unicode, &ignore, 16);
      }
    }
    // Numbered character?
    int n = glyph_to_number(g);
    if (n >= 0)
      return n;
  }
  // The caller must check `contains(g)' before calling get_code(g).
  abort();
}

const char *font::get_name()
{
  return name;
}

const char *font::get_internal_name()
{
  return internalname;
}

const char *font::get_special_device_encoding(glyph *g)
{
  int idx = glyph_to_index(g);
  assert(idx >= 0);
  if (idx < nindices && ch_index[idx] >= 0) {
    // Explicitly enumerated glyph
    return ch[ch_index[idx]].special_device_coding;
  }
  if (is_unicode) {
    // Unicode font
    return NULL;
  }
  abort();
}

const char *font::get_image_generator()
{
  return image_generator;
}

void font::alloc_ch_index(int idx)
{
  if (nindices == 0) {
    nindices = 128;
    if (idx >= nindices)
      nindices = idx + 10;
    ch_index = new int[nindices];
    for (int i = 0; i < nindices; i++)
      ch_index[i] = -1;
  }
  else {
    int old_nindices = nindices;
    nindices *= 2;
    if (idx >= nindices)
      nindices = idx + 10;
    int *old_ch_index = ch_index;
    ch_index = new int[nindices];
    memcpy(ch_index, old_ch_index, sizeof(int)*old_nindices);
    for (int i = old_nindices; i < nindices; i++)
      ch_index[i] = -1;
    a_delete old_ch_index;
  }
}

void font::extend_ch()
{
  if (ch == 0)
    ch = new font_char_metric[ch_size = 16];
  else {
    int old_ch_size = ch_size;
    ch_size *= 2;
    font_char_metric *old_ch = ch;
    ch = new font_char_metric[ch_size];
    memcpy(ch, old_ch, old_ch_size*sizeof(font_char_metric));
    a_delete old_ch;
  }
}

void font::compact()
{
  int i;
  for (i = nindices - 1; i >= 0; i--)
    if (ch_index[i] >= 0)
      break;
  i++;
  if (i < nindices) {
    int *old_ch_index = ch_index;
    ch_index = new int[i];
    memcpy(ch_index, old_ch_index, i*sizeof(int));
    a_delete old_ch_index;
    nindices = i;
  }
  if (ch_used < ch_size) {
    font_char_metric *old_ch = ch;
    ch = new font_char_metric[ch_used];
    memcpy(ch, old_ch, ch_used*sizeof(font_char_metric));
    a_delete old_ch;
    ch_size = ch_used;
  }
}

void font::add_entry(glyph *g, const font_char_metric &metric)
{
  int idx = glyph_to_index(g);
  assert(idx >= 0);
  if (idx >= nindices)
    alloc_ch_index(idx);
  assert(idx < nindices);
  if (ch_used + 1 >= ch_size)
    extend_ch();
  assert(ch_used + 1 < ch_size);
  ch_index[idx] = ch_used;
  ch[ch_used++] = metric;
}

void font::copy_entry(glyph *new_glyph, glyph *old_glyph)
{
  int new_index = glyph_to_index(new_glyph);
  int old_index = glyph_to_index(old_glyph);
  assert(new_index >= 0 && old_index >= 0 && old_index < nindices);
  if (new_index >= nindices)
    alloc_ch_index(new_index);
  ch_index[new_index] = ch_index[old_index];
}

font *font::load_font(const char *s, int *not_found, int head_only)
{
  font *f = new font(s);
  if (!f->load(not_found, head_only)) {
    delete f;
    return 0;
  }
  return f;
}

static char *trim_arg(char *p)
{
  if (!p)
    return 0;
  while (csspace(*p))
    p++;
  char *q = strchr(p, '\0');
  while (q > p && csspace(q[-1]))
    q--;
  *q = '\0';
  return p;
}

int font::scan_papersize(const char *p,
			 const char **size, double *length, double *width)
{
  double l, w;
  char lu[2], wu[2];
  const char *pp = p;
  int test_file = 1;
  char line[255];
again:
  if (csdigit(*pp)) {
    if (sscanf(pp, "%lf%1[ipPc],%lf%1[ipPc]", &l, lu, &w, wu) == 4
	&& l > 0 && w > 0
	&& unit_scale(&l, lu[0]) && unit_scale(&w, wu[0])) {
      if (length)
	*length = l;
      if (width)
	*width = w;
      if (size)
	*size = "custom";
      return 1;
    }
  }
  else {
    int i;
    for (i = 0; i < NUM_PAPERSIZES; i++)
      if (strcasecmp(papersizes[i].name, pp) == 0) {
	if (length)
	  *length = papersizes[i].length;
	if (width)
	  *width = papersizes[i].width;
	if (size)
	  *size = papersizes[i].name;
	return 1;
      }
    if (test_file) {
      FILE *f = fopen(p, "r");
      if (f) {
	fgets(line, 254, f);
	fclose(f);
	test_file = 0;
	char *linep = strchr(line, '\0');
	// skip final newline, if any
	if (*(--linep) == '\n')
	  *linep = '\0';
	pp = line;
	goto again;
      }
    }
  }
  return 0;
}

// If the font can't be found, then if not_found is non-NULL, it will be set
// to 1 otherwise a message will be printed.

int font::load(int *not_found, int head_only)
{
  if (strcmp(name, "DESC") == 0) {
    if (not_found)
      *not_found = 1;
    else
      error("`DESC' is not a valid font file name");
    return 0;
  }
  char *path;
  FILE *fp;
  if ((fp = open_file(name, &path)) == NULL) {
    if (not_found)
      *not_found = 1;
    else
      error("can't find font file `%1'", name);
    return 0;
  }
  text_file t(fp, path);
  t.skip_comments = 1;
  t.silent = head_only;
  char *p;
  for (;;) {
    if (!t.next()) {
      p = 0;
      break;
    }
    p = strtok(t.buf, WS);
    if (strcmp(p, "name") == 0) {
    }
    else if (strcmp(p, "spacewidth") == 0) {
      p = strtok(0, WS);
      int n;
      if (p == 0 || sscanf(p, "%d", &n) != 1 || n <= 0) {
	t.error("bad argument for `spacewidth' command");
	return 0;
      }
      space_width = n;
    }
    else if (strcmp(p, "slant") == 0) {
      p = strtok(0, WS);
      double n;
      if (p == 0 || sscanf(p, "%lf", &n) != 1 || n >= 90.0 || n <= -90.0) {
	t.error("bad argument for `slant' command", p);
	return 0;
      }
      slant = n;
    }
    else if (strcmp(p, "ligatures") == 0) {
      for (;;) {
	p = strtok(0, WS);
	if (p == 0 || strcmp(p, "0") == 0)
	  break;
	if (strcmp(p, "ff") == 0)
	  ligatures |= LIG_ff;
	else if (strcmp(p, "fi") == 0)
	  ligatures |= LIG_fi;
	else if (strcmp(p, "fl") == 0)
	  ligatures |= LIG_fl;
	else if (strcmp(p, "ffi") == 0)
	  ligatures |= LIG_ffi;
	else if (strcmp(p, "ffl") == 0)
	  ligatures |= LIG_ffl;
	else {
	  t.error("unrecognised ligature `%1'", p);
	  return 0;
	}
      }
    }
    else if (strcmp(p, "internalname") == 0) {
      p = strtok(0, WS);
      if (!p) {
	t.error("`internalname' command requires argument");
	return 0;
      }
      internalname = new char[strlen(p) + 1];
      strcpy(internalname, p);
    }
    else if (strcmp(p, "special") == 0) {
      special = 1;
    }
    else if (strcmp(p, "kernpairs") != 0 && strcmp(p, "charset") != 0) {
      char *command = p;
      p = strtok(0, "\n");
      handle_unknown_font_command(command, trim_arg(p), t.path, t.lineno);
    }
    else
      break;
  }
  int had_charset = 0;
  if (p == 0) {
    if (!is_unicode) {
      t.error("missing charset command");
      return 0;
    }
  } else {
    char *command = p;
    t.skip_comments = 0;
    while (command) {
      if (strcmp(command, "kernpairs") == 0) {
	if (head_only)
	  return 1;
	for (;;) {
	  if (!t.next()) {
	    command = 0;
	    break;
	  }
	  char *c1 = strtok(t.buf, WS);
	  if (c1 == 0)
	    continue;
	  char *c2 = strtok(0, WS);
	  if (c2 == 0) {
	    command = c1;
	    break;
	  }
	  p = strtok(0, WS);
	  if (p == 0) {
	    t.error("missing kern amount");
	    return 0;
	  }
	  int n;
	  if (sscanf(p, "%d", &n) != 1) {
	    t.error("bad kern amount `%1'", p);
	    return 0;
	  }
	  glyph *g1 = name_to_glyph(c1);
	  glyph *g2 = name_to_glyph(c2);
	  add_kern(g1, g2, n);
	}
      }
      else if (strcmp(command, "charset") == 0) {
	if (head_only)
	  return 1;
	had_charset = 1;
	glyph *last_glyph = NULL;
	for (;;) {
	  if (!t.next()) {
	    command = 0;
	    break;
	  }
	  char *nm = strtok(t.buf, WS);
	  if (nm == 0)
	    continue;			// I dont think this should happen
	  p = strtok(0, WS);
	  if (p == 0) {
	    command = nm;
	    break;
	  }
	  if (p[0] == '"') {
	    if (last_glyph == NULL) {
	      t.error("first charset entry is duplicate");
	      return 0;
	    }
	    if (strcmp(nm, "---") == 0) {
	      t.error("unnamed character cannot be duplicate");
	      return 0;
	    }
	    glyph *g = name_to_glyph(nm);
	    copy_entry(g, last_glyph);
	  }
	  else {
	    font_char_metric metric;
	    metric.height = 0;
	    metric.depth = 0;
	    metric.pre_math_space = 0;
	    metric.italic_correction = 0;
	    metric.subscript_correction = 0;
	    int nparms = sscanf(p, "%d,%d,%d,%d,%d,%d",
				&metric.width, &metric.height, &metric.depth,
				&metric.italic_correction,
				&metric.pre_math_space,
				&metric.subscript_correction);
	    if (nparms < 1) {
	      t.error("bad width for `%1'", nm);
	      return 0;
	    }
	    p = strtok(0, WS);
	    if (p == 0) {
	      t.error("missing character type for `%1'", nm);
	      return 0;
	    }
	    int type;
	    if (sscanf(p, "%d", &type) != 1) {
	      t.error("bad character type for `%1'", nm);
	      return 0;
	    }
	    if (type < 0 || type > 255) {
	      t.error("character type `%1' out of range", type);
	      return 0;
	    }
	    metric.type = type;
	    p = strtok(0, WS);
	    if (p == 0) {
	      t.error("missing code for `%1'", nm);
	      return 0;
	    }
	    char *ptr;
	    metric.code = (int)strtol(p, &ptr, 0);
	    if (metric.code == 0 && ptr == p) {
	      t.error("bad code `%1' for character `%2'", p, nm);
	      return 0;
	    }
	    p = strtok(0, WS);
	    if ((p == NULL) || (strcmp(p, "--") == 0)) {
	      metric.special_device_coding = NULL;
	    }
	    else {
	      char *nam = new char[strlen(p) + 1];
	      strcpy(nam, p);
	      metric.special_device_coding = nam;
	    }
	    if (strcmp(nm, "---") == 0) {
	      last_glyph = number_to_glyph(metric.code);
	      add_entry(last_glyph, metric);
	    }
	    else {
	      last_glyph = name_to_glyph(nm);
	      add_entry(last_glyph, metric);
	      copy_entry(number_to_glyph(metric.code), last_glyph);
	    }
	  }
	}
	if (last_glyph == NULL) {
	  t.error("I didn't seem to find any characters");
	  return 0;
	}
      }
      else {
	t.error("unrecognised command `%1' "
		"after `kernpairs' or `charset' command",
		  command);
	return 0;
      }
    }
    compact();
  }
  if (!is_unicode && !had_charset) {
    t.error("missing `charset' command");
    return 0;
  }
  if (space_width == 0) {
    if (zoom)
      space_width = scale_round(unitwidth, res, 72 * 3 * sizescale, zoom);
    else
      space_width = scale_round(unitwidth, res, 72 * 3 * sizescale);
  }
  return 1;
}

static struct {
  const char *command;
  int *ptr;
} table[] = {
  { "res", &font::res },
  { "hor", &font::hor },
  { "vert", &font::vert },
  { "unitwidth", &font::unitwidth },
  { "paperwidth", &font::paperwidth },
  { "paperlength", &font::paperlength },
  { "spare1", &font::biggestfont },
  { "biggestfont", &font::biggestfont },
  { "spare2", &font::spare2 },
  { "sizescale", &font::sizescale },
  };

int font::load_desc()
{
  int nfonts = 0;
  FILE *fp;
  char *path;
  if ((fp = open_file("DESC", &path)) == 0) {
    error("can't find `DESC' file");
    return 0;
  }
  text_file t(fp, path);
  t.skip_comments = 1;
  res = 0;
  while (t.next()) {
    char *p = strtok(t.buf, WS);
    int found = 0;
    unsigned int idx;
    for (idx = 0; !found && idx < sizeof(table)/sizeof(table[0]); idx++)
      if (strcmp(table[idx].command, p) == 0)
	found = 1;
    if (found) {
      char *q = strtok(0, WS);
      if (!q) {
	t.error("missing value for command `%1'", p);
	return 0;
      }
      //int *ptr = &(this->*(table[idx-1].ptr));
      int *ptr = table[idx-1].ptr;
      if (sscanf(q, "%d", ptr) != 1) {
	t.error("bad number `%1'", q);
	return 0;
      }
    }
    else if (strcmp("family", p) == 0) {
      p = strtok(0, WS);
      if (!p) {
	t.error("family command requires an argument");
	return 0;
      }
      char *tem = new char[strlen(p)+1];
      strcpy(tem, p);
      family = tem;
    }
    else if (strcmp("fonts", p) == 0) {
      p = strtok(0, WS);
      if (!p || sscanf(p, "%d", &nfonts) != 1 || nfonts <= 0) {
	t.error("bad number of fonts `%1'", p);
	return 0;
      }
      font_name_table = (const char **)new char *[nfonts+1]; 
      for (int i = 0; i < nfonts; i++) {
	p = strtok(0, WS);
	while (p == 0) {
	  if (!t.next()) {
	    t.error("end of file while reading list of fonts");
	    return 0;
	  }
	  p = strtok(t.buf, WS);
	}
	char *temp = new char[strlen(p)+1];
	strcpy(temp, p);
	font_name_table[i] = temp;
      }
      p = strtok(0, WS);
      if (p != 0) {
	t.error("font count does not match number of fonts");
	return 0;
      }
      font_name_table[nfonts] = 0;
    }
    else if (strcmp("papersize", p) == 0) {
      p = strtok(0, WS);
      if (!p) {
	t.error("papersize command requires an argument");
	return 0;
      }
      int found_paper = 0;
      while (p) {
	double unscaled_paperwidth, unscaled_paperlength;
	if (scan_papersize(p, &papersize, &unscaled_paperlength,
			   &unscaled_paperwidth)) {
	  paperwidth = int(unscaled_paperwidth * res + 0.5);
	  paperlength = int(unscaled_paperlength * res + 0.5);
	  found_paper = 1;
	  break;
	}
	p = strtok(0, WS);
      }
      if (!found_paper) {
	t.error("bad paper size");
	return 0;
      }
    }
    else if (strcmp("unscaled_charwidths", p) == 0)
      unscaled_charwidths = 1;
    else if (strcmp("pass_filenames", p) == 0)
      pass_filenames = 1;
    else if (strcmp("sizes", p) == 0) {
      int n = 16;
      sizes = new int[n];
      int i = 0;
      for (;;) {
	p = strtok(0, WS);
	while (p == 0) {
	  if (!t.next()) {
	    t.error("list of sizes must be terminated by `0'");
	    return 0;
	  }
	  p = strtok(t.buf, WS);
	}
	int lower, upper;
	switch (sscanf(p, "%d-%d", &lower, &upper)) {
	case 1:
	  upper = lower;
	  // fall through
	case 2:
	  if (lower <= upper && lower >= 0)
	    break;
	  // fall through
	default:
	  t.error("bad size range `%1'", p);
	  return 0;
	}
	if (i + 2 > n) {
	  int *old_sizes = sizes;
	  sizes = new int[n*2];
	  memcpy(sizes, old_sizes, n*sizeof(int));
	  n *= 2;
	  a_delete old_sizes;
	}
	sizes[i++] = lower;
	if (lower == 0)
	  break;
	sizes[i++] = upper;
      }
      if (i == 1) {
	t.error("must have some sizes");
	return 0;
      }
    }
    else if (strcmp("styles", p) == 0) {
      int style_table_size = 5;
      style_table = (const char **)new char *[style_table_size];
      int j;
      for (j = 0; j < style_table_size; j++)
	style_table[j] = 0;
      int i = 0;
      for (;;) {
	p = strtok(0, WS);
	if (p == 0)
	  break;
	// leave room for terminating 0
	if (i + 1 >= style_table_size) {
	  const char **old_style_table = style_table;
	  style_table_size *= 2;
	  style_table = (const char **)new char*[style_table_size];
	  for (j = 0; j < i; j++)
	    style_table[j] = old_style_table[j];
	  for (; j < style_table_size; j++)
	    style_table[j] = 0;
	  a_delete old_style_table;
	}
	char *tem = new char[strlen(p) + 1];
	strcpy(tem, p);
	style_table[i++] = tem;
      }
    }
    else if (strcmp("tcommand", p) == 0)
      tcommand = 1;
    else if (strcmp("use_charnames_in_special", p) == 0)
      use_charnames_in_special = 1;
    else if (strcmp("unicode", p) == 0)
      is_unicode = 1;
    else if (strcmp("image_generator", p) == 0) {
      p = strtok(0, WS);
      if (!p) {
	t.error("image_generator command requires an argument");
	return 0;
      }
      image_generator = strsave(p);
    }
    else if (strcmp("charset", p) == 0)
      break;
    else if (unknown_desc_command_handler) {
      char *command = p;
      p = strtok(0, "\n");
      (*unknown_desc_command_handler)(command, trim_arg(p), t.path, t.lineno);
    }
  }
  if (res == 0) {
    t.error("missing `res' command");
    return 0;
  }
  if (unitwidth == 0) {
    t.error("missing `unitwidth' command");
    return 0;
  }
  if (font_name_table == 0) {
    t.error("missing `fonts' command");
    return 0;
  }
  if (sizes == 0) {
    t.error("missing `sizes' command");
    return 0;
  }
  if (sizescale < 1) {
    t.error("bad `sizescale' value");
    return 0;
  }
  if (hor < 1) {
    t.error("bad `hor' value");
    return 0;
  }
  if (vert < 1) {
    t.error("bad `vert' value");
    return 0;
  }
  return 1;
}      

void font::handle_unknown_font_command(const char *, const char *,
				       const char *, int)
{
}

FONT_COMMAND_HANDLER
font::set_unknown_desc_command_handler(FONT_COMMAND_HANDLER func)
{
  FONT_COMMAND_HANDLER prev = unknown_desc_command_handler;
  unknown_desc_command_handler = func;
  return prev;
}