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[emacs.git] / src / font.c

/* font.c -- "Font" primitives.

Copyright (C) 2006-2018 Free Software Foundation, Inc.
Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011
  National Institute of Advanced Industrial Science and Technology (AIST)
  Registration Number H13PRO009

This file is part of GNU Emacs.

GNU Emacs 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.

GNU Emacs 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 GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>
#include <float.h>
#include <stdio.h>
#include <stdlib.h>

#include <c-ctype.h>

#include "lisp.h"
#include "character.h"
#include "buffer.h"
#include "frame.h"
#include "window.h"
#include "dispextern.h"
#include "charset.h"
#include "composite.h"
#include "fontset.h"
#include "font.h"
#include "termhooks.h"

#ifdef HAVE_WINDOW_SYSTEM
#include TERM_HEADER
#endif /* HAVE_WINDOW_SYSTEM */

#define DEFAULT_ENCODING Qiso8859_1

/* Vector of Vfont_weight_table, Vfont_slant_table, and Vfont_width_table. */
static Lisp_Object font_style_table;

/* Structure used for tables mapping weight, slant, and width numeric
   values and their names.  */

struct table_entry
{
  int numeric;
  /* The first one is a valid name as a face attribute.
     The second one (if any) is a typical name in XLFD field.  */
  const char *names[5];
};

/* Table of weight numeric values and their names.  This table must be
   sorted by numeric values in ascending order.  */

static const struct table_entry weight_table[] =
{
  { 0, { "thin" }},
  { 20, { "ultra-light", "ultralight" }},
  { 40, { "extra-light", "extralight" }},
  { 50, { "light" }},
  { 75, { "semi-light", "semilight", "demilight", "book" }},
  { 100, { "normal", "medium", "regular", "unspecified" }},
  { 180, { "semi-bold", "semibold", "demibold", "demi" }},
  { 200, { "bold" }},
  { 205, { "extra-bold", "extrabold" }},
  { 210, { "ultra-bold", "ultrabold", "black" }}
};

/* Table of slant numeric values and their names.  This table must be
   sorted by numeric values in ascending order.  */

static const struct table_entry slant_table[] =
{
  { 0, { "reverse-oblique", "ro" }},
  { 10, { "reverse-italic", "ri" }},
  { 100, { "normal", "r", "unspecified" }},
  { 200, { "italic" ,"i", "ot" }},
  { 210, { "oblique", "o" }}
};

/* Table of width numeric values and their names.  This table must be
   sorted by numeric values in ascending order.  */

static const struct table_entry width_table[] =
{
  { 50, { "ultra-condensed", "ultracondensed" }},
  { 63, { "extra-condensed", "extracondensed" }},
  { 75, { "condensed", "compressed", "narrow" }},
  { 87, { "semi-condensed", "semicondensed", "demicondensed" }},
  { 100, { "normal", "medium", "regular", "unspecified" }},
  { 113, { "semi-expanded", "semiexpanded", "demiexpanded" }},
  { 125, { "expanded" }},
  { 150, { "extra-expanded", "extraexpanded" }},
  { 200, { "ultra-expanded", "ultraexpanded", "wide" }}
};

/* Alist of font registry symbols and the corresponding charset
   information.  The information is retrieved from
   Vfont_encoding_alist on demand.

   Eash element has the form:
        (REGISTRY . (ENCODING-CHARSET-ID . REPERTORY-CHARSET-ID))
   or
        (REGISTRY . nil)

   In the former form, ENCODING-CHARSET-ID is an ID of a charset that
   encodes a character code to a glyph code of a font, and
   REPERTORY-CHARSET-ID is an ID of a charset that tells if a
   character is supported by a font.

   The latter form means that the information for REGISTRY couldn't be
   retrieved.  */
static Lisp_Object font_charset_alist;

/* List of all font drivers.  Each font-backend (XXXfont.c) calls
   register_font_driver in syms_of_XXXfont to register its font-driver
   here.  */
static struct font_driver_list *font_driver_list;

#ifdef ENABLE_CHECKING

/* Used to catch bogus pointers in font objects.  */

bool
valid_font_driver (struct font_driver const *drv)
{
  Lisp_Object tail, frame;
  struct font_driver_list *fdl;

  for (fdl = font_driver_list; fdl; fdl = fdl->next)
    if (fdl->driver == drv)
      return true;
  FOR_EACH_FRAME (tail, frame)
    for (fdl = XFRAME (frame)->font_driver_list; fdl; fdl = fdl->next)
      if (fdl->driver == drv)
        return true;
  return false;
}

#endif /* ENABLE_CHECKING */

/* Creators of font-related Lisp object.  */

static Lisp_Object
font_make_spec (void)
{
  Lisp_Object font_spec;
  struct font_spec *spec
    = ((struct font_spec *)
       allocate_pseudovector (VECSIZE (struct font_spec),
                              FONT_SPEC_MAX, FONT_SPEC_MAX, PVEC_FONT));
  XSETFONT (font_spec, spec);
  return font_spec;
}

Lisp_Object
font_make_entity (void)
{
  Lisp_Object font_entity;
  struct font_entity *entity
    = ((struct font_entity *)
       allocate_pseudovector (VECSIZE (struct font_entity),
                              FONT_ENTITY_MAX, FONT_ENTITY_MAX, PVEC_FONT));
  XSETFONT (font_entity, entity);
  return font_entity;
}

/* Create a font-object whose structure size is SIZE.  If ENTITY is
   not nil, copy properties from ENTITY to the font-object.  If
   PIXELSIZE is positive, set the `size' property to PIXELSIZE.  */
Lisp_Object
font_make_object (int size, Lisp_Object entity, int pixelsize)
{
  Lisp_Object font_object;
  struct font *font
    = (struct font *) allocate_pseudovector (size, FONT_OBJECT_MAX,
                                             FONT_OBJECT_MAX, PVEC_FONT);
  int i;

  /* GC can happen before the driver is set up,
     so avoid dangling pointer here (Bug#17771).  */
  font->driver = NULL;
  XSETFONT (font_object, font);

  if (! NILP (entity))
    {
      for (i = 1; i < FONT_SPEC_MAX; i++)
        font->props[i] = AREF (entity, i);
      if (! NILP (AREF (entity, FONT_EXTRA_INDEX)))
        font->props[FONT_EXTRA_INDEX]
          = Fcopy_alist (AREF (entity, FONT_EXTRA_INDEX));
    }
  if (size > 0)
    font->props[FONT_SIZE_INDEX] = make_number (pixelsize);
  return font_object;
}

#if defined (HAVE_XFT) || defined (HAVE_FREETYPE) || defined (HAVE_NS)

static int font_unparse_fcname (Lisp_Object, int, char *, int);

/* Like above, but also set `type', `name' and `fullname' properties
   of font-object.  */

Lisp_Object
font_build_object (int vectorsize, Lisp_Object type,
                   Lisp_Object entity, double pixelsize)
{
  int len;
  char name[256];
  Lisp_Object font_object = font_make_object (vectorsize, entity, pixelsize);

  ASET (font_object, FONT_TYPE_INDEX, type);
  len = font_unparse_xlfd (entity, pixelsize, name, sizeof name);
  if (len > 0)
    ASET (font_object, FONT_NAME_INDEX, make_string (name, len));
  len = font_unparse_fcname (entity, pixelsize, name, sizeof name);
  if (len > 0)
    ASET (font_object, FONT_FULLNAME_INDEX, make_string (name, len));
  else
    ASET (font_object, FONT_FULLNAME_INDEX,
          AREF (font_object, FONT_NAME_INDEX));
  return font_object;
}

#endif /* HAVE_XFT || HAVE_FREETYPE || HAVE_NS */

static int font_pixel_size (struct frame *f, Lisp_Object);
static Lisp_Object font_open_entity (struct frame *, Lisp_Object, int);
static Lisp_Object font_matching_entity (struct frame *, Lisp_Object *,
                                         Lisp_Object);
static unsigned font_encode_char (Lisp_Object, int);

/* Number of registered font drivers.  */
static int num_font_drivers;


/* Return a Lispy value of a font property value at STR and LEN bytes.
   If STR is "*", return nil.  If FORCE_SYMBOL, or if STR does not
   consist entirely of one or more digits, return a symbol interned
   from STR.  Otherwise, return an integer.  */

Lisp_Object
font_intern_prop (const char *str, ptrdiff_t len, bool force_symbol)
{
  ptrdiff_t i, nbytes, nchars;
  Lisp_Object tem, name, obarray;

  if (len == 1 && *str == '*')
    return Qnil;
  if (!force_symbol && 0 < len && '0' <= *str && *str <= '9')
    {
      for (i = 1; i < len; i++)
        if (! ('0' <= str[i] && str[i] <= '9'))
          break;
      if (i == len)
        {
          i = 0;
          for (EMACS_INT n = 0;
               (n += str[i++] - '0') <= MOST_POSITIVE_FIXNUM; )
            {
              if (i == len)
                return make_number (n);
              if (INT_MULTIPLY_WRAPV (n, 10, &n))
                break;
            }

          xsignal1 (Qoverflow_error, make_string (str, len));
        }
    }

  /* This code is similar to intern function from lread.c.  */
  obarray = check_obarray (Vobarray);
  parse_str_as_multibyte ((unsigned char *) str, len, &nchars, &nbytes);
  tem = oblookup (obarray, str,
                  (len == nchars || len != nbytes) ? len : nchars, len);
  if (SYMBOLP (tem))
    return tem;
  name = make_specified_string (str, nchars, len,
                                len != nchars && len == nbytes);
  return intern_driver (name, obarray, tem);
}

/* Return a pixel size of font-spec SPEC on frame F.  */

static int
font_pixel_size (struct frame *f, Lisp_Object spec)
{
#ifdef HAVE_WINDOW_SYSTEM
  Lisp_Object size = AREF (spec, FONT_SIZE_INDEX);
  double point_size;
  int dpi, pixel_size;
  Lisp_Object val;

  if (INTEGERP (size))
    return XINT (size);
  if (NILP (size))
    return 0;
  if (FRAME_WINDOW_P (f))
    {
      eassert (FLOATP (size));
      point_size = XFLOAT_DATA (size);
      val = AREF (spec, FONT_DPI_INDEX);
      if (INTEGERP (val))
        dpi = XINT (val);
      else
        dpi = FRAME_RES_Y (f);
      pixel_size = POINT_TO_PIXEL (point_size, dpi);
      return pixel_size;
    }
#endif
  return 1;
}


/* Return a value of PROP's VAL (symbol or integer) to be stored in a
   font vector.  If VAL is not valid (i.e. not registered in
   font_style_table), return -1 if NOERROR is zero, and return a
   proper index if NOERROR is nonzero.  In that case, register VAL in
   font_style_table if VAL is a symbol, and return the closest index if
   VAL is an integer.  */

int
font_style_to_value (enum font_property_index prop, Lisp_Object val,
                     bool noerror)
{
  Lisp_Object table = AREF (font_style_table, prop - FONT_WEIGHT_INDEX);
  int len;

  CHECK_VECTOR (table);
  len = ASIZE (table);

  if (SYMBOLP (val))
    {
      int i, j;
      char *s;
      Lisp_Object elt;

      /* At first try exact match.  */
      for (i = 0; i < len; i++)
        {
          CHECK_VECTOR (AREF (table, i));
          for (j = 1; j < ASIZE (AREF (table, i)); j++)
            if (EQ (val, AREF (AREF (table, i), j)))
              {
                CHECK_NUMBER (AREF (AREF (table, i), 0));
                return ((XINT (AREF (AREF (table, i), 0)) << 8)
                        | (i << 4) | (j - 1));
              }
        }
      /* Try also with case-folding match.  */
      s = SSDATA (SYMBOL_NAME (val));
      for (i = 0; i < len; i++)
        for (j = 1; j < ASIZE (AREF (table, i)); j++)
          {
            elt = AREF (AREF (table, i), j);
            if (xstrcasecmp (s, SSDATA (SYMBOL_NAME (elt))) == 0)
              {
                CHECK_NUMBER (AREF (AREF (table, i), 0));
                return ((XINT (AREF (AREF (table, i), 0)) << 8)
                        | (i << 4) | (j - 1));
              }
          }
      if (! noerror)
        return -1;
      eassert (len < 255);
      elt = Fmake_vector (make_number (2), make_number (100));
      ASET (elt, 1, val);
      ASET (font_style_table, prop - FONT_WEIGHT_INDEX,
            CALLN (Fvconcat, table, Fmake_vector (make_number (1), elt)));
      return (100 << 8) | (i << 4);
    }
  else
    {
      int i, last_n;
      EMACS_INT numeric = XINT (val);

      for (i = 0, last_n = -1; i < len; i++)
        {
          int n;

          CHECK_VECTOR (AREF (table, i));
          CHECK_NUMBER (AREF (AREF (table, i), 0));
          n = XINT (AREF (AREF (table, i), 0));
          if (numeric == n)
            return (n << 8) | (i << 4);
          if (numeric < n)
            {
              if (! noerror)
                return -1;
              return ((i == 0 || n - numeric < numeric - last_n)
                      ? (n << 8) | (i << 4): (last_n << 8 | ((i - 1) << 4)));
            }
          last_n = n;
        }
      if (! noerror)
        return -1;
      return ((last_n << 8) | ((i - 1) << 4));
    }
}

Lisp_Object
font_style_symbolic (Lisp_Object font, enum font_property_index prop,
                     bool for_face)
{
  Lisp_Object val = AREF (font, prop);
  Lisp_Object table, elt;
  int i;

  if (NILP (val))
    return Qnil;
  table = AREF (font_style_table, prop - FONT_WEIGHT_INDEX);
  CHECK_VECTOR (table);
  i = XINT (val) & 0xFF;
  eassert (((i >> 4) & 0xF) < ASIZE (table));
  elt = AREF (table, ((i >> 4) & 0xF));
  CHECK_VECTOR (elt);
  eassert ((i & 0xF) + 1 < ASIZE (elt));
  elt = (for_face ? AREF (elt, 1) : AREF (elt, (i & 0xF) + 1));
  CHECK_SYMBOL (elt);
  return elt;
}

/* Return ENCODING or a cons of ENCODING and REPERTORY of the font
   FONTNAME.  ENCODING is a charset symbol that specifies the encoding
   of the font.  REPERTORY is a charset symbol or nil.  */

Lisp_Object
find_font_encoding (Lisp_Object fontname)
{
  Lisp_Object tail, elt;

  for (tail = Vfont_encoding_alist; CONSP (tail); tail = XCDR (tail))
    {
      elt = XCAR (tail);
      if (CONSP (elt)
          && STRINGP (XCAR (elt))
          && fast_string_match_ignore_case (XCAR (elt), fontname) >= 0
          && (SYMBOLP (XCDR (elt))
              ? CHARSETP (XCDR (elt))
              : CONSP (XCDR (elt)) && CHARSETP (XCAR (XCDR (elt)))))
        return (XCDR (elt));
    }
  return Qnil;
}

/* Return encoding charset and repertory charset for REGISTRY in
   ENCODING and REPERTORY correspondingly.  If correct information for
   REGISTRY is available, return 0.  Otherwise return -1.  */

int
font_registry_charsets (Lisp_Object registry, struct charset **encoding, struct charset **repertory)
{
  Lisp_Object val;
  int encoding_id, repertory_id;

  val = Fassoc_string (registry, font_charset_alist, Qt);
  if (! NILP (val))
    {
      val = XCDR (val);
      if (NILP (val))
        return -1;
      encoding_id = XINT (XCAR (val));
      repertory_id = XINT (XCDR (val));
    }
  else
    {
      val = find_font_encoding (SYMBOL_NAME (registry));
      if (SYMBOLP (val) && CHARSETP (val))
        {
          encoding_id = repertory_id = XINT (CHARSET_SYMBOL_ID (val));
        }
      else if (CONSP (val))
        {
          if (! CHARSETP (XCAR (val)))
            goto invalid_entry;
          encoding_id = XINT (CHARSET_SYMBOL_ID (XCAR (val)));
          if (NILP (XCDR (val)))
            repertory_id = -1;
          else
            {
              if (! CHARSETP (XCDR (val)))
                goto invalid_entry;
              repertory_id = XINT (CHARSET_SYMBOL_ID (XCDR (val)));
            }
        }
      else
        goto invalid_entry;
      val = Fcons (make_number (encoding_id), make_number (repertory_id));
      font_charset_alist
        = nconc2 (font_charset_alist, list1 (Fcons (registry, val)));
    }

  if (encoding)
    *encoding = CHARSET_FROM_ID (encoding_id);
  if (repertory)
    *repertory = repertory_id >= 0 ? CHARSET_FROM_ID (repertory_id) : NULL;
  return 0;

 invalid_entry:
  font_charset_alist
    = nconc2 (font_charset_alist, list1 (Fcons (registry, Qnil)));
  return -1;
}

\f
/* Font property value validators.  See the comment of
   font_property_table for the meaning of the arguments.  */

static Lisp_Object font_prop_validate (int, Lisp_Object, Lisp_Object);
static Lisp_Object font_prop_validate_symbol (Lisp_Object, Lisp_Object);
static Lisp_Object font_prop_validate_style (Lisp_Object, Lisp_Object);
static Lisp_Object font_prop_validate_non_neg (Lisp_Object, Lisp_Object);
static Lisp_Object font_prop_validate_spacing (Lisp_Object, Lisp_Object);
static int get_font_prop_index (Lisp_Object);

static Lisp_Object
font_prop_validate_symbol (Lisp_Object prop, Lisp_Object val)
{
  if (STRINGP (val))
    val = Fintern (val, Qnil);
  if (! SYMBOLP (val))
    val = Qerror;
  else if (EQ (prop, QCregistry))
    val = Fintern (Fdowncase (SYMBOL_NAME (val)), Qnil);
  return val;
}


static Lisp_Object
font_prop_validate_style (Lisp_Object style, Lisp_Object val)
{
  enum font_property_index prop = (EQ (style, QCweight) ? FONT_WEIGHT_INDEX
                                   : EQ (style, QCslant) ? FONT_SLANT_INDEX
                                   : FONT_WIDTH_INDEX);
  if (INTEGERP (val))
    {
      EMACS_INT n = XINT (val);
      CHECK_VECTOR (AREF (font_style_table, prop - FONT_WEIGHT_INDEX));
      if (((n >> 4) & 0xF)
          >= ASIZE (AREF (font_style_table, prop - FONT_WEIGHT_INDEX)))
        val = Qerror;
      else
        {
          Lisp_Object elt = AREF (AREF (font_style_table, prop - FONT_WEIGHT_INDEX), (n >> 4) & 0xF);

          CHECK_VECTOR (elt);
          if ((n & 0xF) + 1 >= ASIZE (elt))
            val = Qerror;
          else
            {
              CHECK_NUMBER (AREF (elt, 0));
              if (XINT (AREF (elt, 0)) != (n >> 8))
                val = Qerror;
            }
        }
    }
  else if (SYMBOLP (val))
    {
      int n = font_style_to_value (prop, val, 0);

      val = n >= 0 ? make_number (n) : Qerror;
    }
  else
    val = Qerror;
  return val;
}

static Lisp_Object
font_prop_validate_non_neg (Lisp_Object prop, Lisp_Object val)
{
  return (NATNUMP (val) || (FLOATP (val) && XFLOAT_DATA (val) >= 0)
          ? val : Qerror);
}

static Lisp_Object
font_prop_validate_spacing (Lisp_Object prop, Lisp_Object val)
{
  if (NILP (val) || (NATNUMP (val) && XINT (val) <= FONT_SPACING_CHARCELL))
    return val;
  if (SYMBOLP (val) && SBYTES (SYMBOL_NAME (val)) == 1)
    {
      char spacing = SDATA (SYMBOL_NAME (val))[0];

      if (spacing == 'c' || spacing == 'C')
        return make_number (FONT_SPACING_CHARCELL);
      if (spacing == 'm' || spacing == 'M')
        return make_number (FONT_SPACING_MONO);
      if (spacing == 'p' || spacing == 'P')
        return make_number (FONT_SPACING_PROPORTIONAL);
      if (spacing == 'd' || spacing == 'D')
        return make_number (FONT_SPACING_DUAL);
    }
  return Qerror;
}

static Lisp_Object
font_prop_validate_otf (Lisp_Object prop, Lisp_Object val)
{
  Lisp_Object tail, tmp;
  int i;

  /* VAL = (SCRIPT [ LANGSYS [ GSUB-FEATURES [ GPOS-FEATURES ]]])
     GSUB-FEATURES = (FEATURE ... [ nil FEATURE ... ]) | nil
     GPOS-FEATURES = (FEATURE ... [ nil FEATURE ... ]) | nil  */
  if (! CONSP (val))
    return Qerror;
  if (! SYMBOLP (XCAR (val)))
    return Qerror;
  tail = XCDR (val);
  if (NILP (tail))
    return val;
  if (! CONSP (tail) || ! SYMBOLP (XCAR (val)))
    return Qerror;
  for (i = 0; i < 2; i++)
    {
      tail = XCDR (tail);
      if (NILP (tail))
        return val;
      if (! CONSP (tail))
        return Qerror;
      for (tmp = XCAR (tail); CONSP (tmp); tmp = XCDR (tmp))
        if (! SYMBOLP (XCAR (tmp)))
          return Qerror;
      if (! NILP (tmp))
        return Qerror;
    }
  return val;
}

/* Structure of known font property keys and validator of the
   values.  */
static const struct
{
  /* Index of the key symbol.  */
  int key;
  /* Function to validate PROP's value VAL, or NULL if any value is
     ok.  The value is VAL or its regularized value if VAL is valid,
     and Qerror if not.  */
  Lisp_Object (*validator) (Lisp_Object prop, Lisp_Object val);
} font_property_table[] =
  { { SYMBOL_INDEX (QCtype), font_prop_validate_symbol },
    { SYMBOL_INDEX (QCfoundry), font_prop_validate_symbol },
    { SYMBOL_INDEX (QCfamily), font_prop_validate_symbol },
    { SYMBOL_INDEX (QCadstyle), font_prop_validate_symbol },
    { SYMBOL_INDEX (QCregistry), font_prop_validate_symbol },
    { SYMBOL_INDEX (QCweight), font_prop_validate_style },
    { SYMBOL_INDEX (QCslant), font_prop_validate_style },
    { SYMBOL_INDEX (QCwidth), font_prop_validate_style },
    { SYMBOL_INDEX (QCsize), font_prop_validate_non_neg },
    { SYMBOL_INDEX (QCdpi), font_prop_validate_non_neg },
    { SYMBOL_INDEX (QCspacing), font_prop_validate_spacing },
    { SYMBOL_INDEX (QCavgwidth), font_prop_validate_non_neg },
    /* The order of the above entries must match with enum
       font_property_index.  */
    { SYMBOL_INDEX (QClang), font_prop_validate_symbol },
    { SYMBOL_INDEX (QCscript), font_prop_validate_symbol },
    { SYMBOL_INDEX (QCotf), font_prop_validate_otf }
  };

/* Return an index number of font property KEY or -1 if KEY is not an
   already known property.  */

static int
get_font_prop_index (Lisp_Object key)
{
  int i;

  for (i = 0; i < ARRAYELTS (font_property_table); i++)
    if (EQ (key, builtin_lisp_symbol (font_property_table[i].key)))
      return i;
  return -1;
}

/* Validate the font property.  The property key is specified by the
   symbol PROP, or the index IDX (if PROP is nil).  If VAL is invalid,
   signal an error.  The value is VAL or the regularized one.  */

static Lisp_Object
font_prop_validate (int idx, Lisp_Object prop, Lisp_Object val)
{
  Lisp_Object validated;

  if (NILP (val))
    return val;
  if (NILP (prop))
    prop = builtin_lisp_symbol (font_property_table[idx].key);
  else
    {
      idx = get_font_prop_index (prop);
      if (idx < 0)
        return val;
    }
  validated = (font_property_table[idx].validator) (prop, val);
  if (EQ (validated, Qerror))
    signal_error ("invalid font property", Fcons (prop, val));
  return validated;
}


/* Store VAL as a value of extra font property PROP in FONT while
   keeping the sorting order.  Don't check the validity of VAL.  */

Lisp_Object
font_put_extra (Lisp_Object font, Lisp_Object prop, Lisp_Object val)
{
  Lisp_Object extra = AREF (font, FONT_EXTRA_INDEX);
  Lisp_Object slot = (NILP (extra) ? Qnil : assq_no_quit (prop, extra));

  if (NILP (slot))
    {
      Lisp_Object prev = Qnil;

      while (CONSP (extra)
             && NILP (Fstring_lessp (prop, XCAR (XCAR (extra)))))
        prev = extra, extra = XCDR (extra);

      if (NILP (prev))
        ASET (font, FONT_EXTRA_INDEX, Fcons (Fcons (prop, val), extra));
      else
        XSETCDR (prev, Fcons (Fcons (prop, val), extra));

      return val;
    }
  XSETCDR (slot, val);
  if (NILP (val))
    ASET (font, FONT_EXTRA_INDEX, Fdelq (slot, extra));
  return val;
}

\f
/* Font name parser and unparser.  */

static int parse_matrix (const char *);
static int font_expand_wildcards (Lisp_Object *, int);
static int font_parse_name (char *, ptrdiff_t, Lisp_Object);

/* An enumerator for each field of an XLFD font name.  */
enum xlfd_field_index
{
  XLFD_FOUNDRY_INDEX,
  XLFD_FAMILY_INDEX,
  XLFD_WEIGHT_INDEX,
  XLFD_SLANT_INDEX,
  XLFD_SWIDTH_INDEX,
  XLFD_ADSTYLE_INDEX,
  XLFD_PIXEL_INDEX,
  XLFD_POINT_INDEX,
  XLFD_RESX_INDEX,
  XLFD_RESY_INDEX,
  XLFD_SPACING_INDEX,
  XLFD_AVGWIDTH_INDEX,
  XLFD_REGISTRY_INDEX,
  XLFD_ENCODING_INDEX,
  XLFD_LAST_INDEX
};

/* An enumerator for mask bit corresponding to each XLFD field.  */
enum xlfd_field_mask
{
  XLFD_FOUNDRY_MASK = 0x0001,
  XLFD_FAMILY_MASK = 0x0002,
  XLFD_WEIGHT_MASK = 0x0004,
  XLFD_SLANT_MASK = 0x0008,
  XLFD_SWIDTH_MASK = 0x0010,
  XLFD_ADSTYLE_MASK = 0x0020,
  XLFD_PIXEL_MASK = 0x0040,
  XLFD_POINT_MASK = 0x0080,
  XLFD_RESX_MASK = 0x0100,
  XLFD_RESY_MASK = 0x0200,
  XLFD_SPACING_MASK = 0x0400,
  XLFD_AVGWIDTH_MASK = 0x0800,
  XLFD_REGISTRY_MASK = 0x1000,
  XLFD_ENCODING_MASK = 0x2000
};


/* Parse P pointing to the pixel/point size field of the form
   `[A B C D]' which specifies a transformation matrix:

        A  B  0
        C  D  0
        0  0  1

   by which all glyphs of the font are transformed.  The spec says
   that scalar value N for the pixel/point size is equivalent to:
   A = N * resx/resy, B = C = 0, D = N.

   Return the scalar value N if the form is valid.  Otherwise return
   -1.  */

static int
parse_matrix (const char *p)
{
  double matrix[4];
  char *end;
  int i;

  for (i = 0, p++; i < 4 && *p && *p != ']'; i++)
    {
      if (*p == '~')
        matrix[i] = - strtod (p + 1, &end);
      else
        matrix[i] = strtod (p, &end);
      p = end;
    }
  return (i == 4 ? (int) matrix[3] : -1);
}

/* Expand a wildcard field in FIELD (the first N fields are filled) to
   multiple fields to fill in all 14 XLFD fields while restricting a
   field position by its contents.  */

static int
font_expand_wildcards (Lisp_Object *field, int n)
{
  /* Copy of FIELD.  */
  Lisp_Object tmp[XLFD_LAST_INDEX];
  /* Array of information about where this element can go.  Nth
     element is for Nth element of FIELD. */
  struct {
    /* Minimum possible field.  */
    int from;
    /* Maximum possible field.  */
    int to;
    /* Bit mask of possible field.  Nth bit corresponds to Nth field.  */
    int mask;
  } range[XLFD_LAST_INDEX];
  int i, j;
  int range_from, range_to;
  unsigned range_mask;

#define XLFD_SYMBOL_MASK (XLFD_FOUNDRY_MASK | XLFD_FAMILY_MASK \
                          | XLFD_ADSTYLE_MASK  | XLFD_REGISTRY_MASK)
#define XLFD_NULL_MASK (XLFD_FOUNDRY_MASK | XLFD_ADSTYLE_MASK)
#define XLFD_LARGENUM_MASK (XLFD_POINT_MASK | XLFD_RESX_MASK | XLFD_RESY_MASK \
                            | XLFD_AVGWIDTH_MASK)
#define XLFD_REGENC_MASK (XLFD_REGISTRY_MASK | XLFD_ENCODING_MASK)

  /* Initialize RANGE_MASK for FIELD[0] which can be 0th to (14 - N)th
     field.  The value is shifted to left one bit by one in the
     following loop.  */
  for (i = 0, range_mask = 0; i <= 14 - n; i++)
    range_mask = (range_mask << 1) | 1;

  /* The triplet RANGE_FROM, RANGE_TO, and RANGE_MASK is a
     position-based restriction for FIELD[I].  */
  for (i = 0, range_from = 0, range_to = 14 - n; i < n;
       i++, range_from++, range_to++, range_mask <<= 1)
    {
      Lisp_Object val = field[i];

      tmp[i] = val;
      if (NILP (val))
        {
          /* Wildcard.  */
          range[i].from = range_from;
          range[i].to = range_to;
          range[i].mask = range_mask;
        }
      else
        {
          /* The triplet FROM, TO, and MASK is a value-based
             restriction for FIELD[I].  */
          int from, to;
          unsigned mask;

          if (INTEGERP (val))
            {
              EMACS_INT numeric = XINT (val);

              if (i + 1 == n)
                from = to = XLFD_ENCODING_INDEX,
                  mask = XLFD_ENCODING_MASK;
              else if (numeric == 0)
                from = XLFD_PIXEL_INDEX, to = XLFD_AVGWIDTH_INDEX,
                  mask = XLFD_PIXEL_MASK | XLFD_LARGENUM_MASK;
              else if (numeric <= 48)
                from = to = XLFD_PIXEL_INDEX,
                  mask = XLFD_PIXEL_MASK;
              else
                from = XLFD_POINT_INDEX, to = XLFD_AVGWIDTH_INDEX,
                  mask = XLFD_LARGENUM_MASK;
            }
          else if (SBYTES (SYMBOL_NAME (val)) == 0)
            from = XLFD_FOUNDRY_INDEX, to = XLFD_ADSTYLE_INDEX,
              mask = XLFD_NULL_MASK;
          else if (i == 0)
            from = to = XLFD_FOUNDRY_INDEX, mask = XLFD_FOUNDRY_MASK;
          else if (i + 1 == n)
            {
              Lisp_Object name = SYMBOL_NAME (val);

              if (SDATA (name)[SBYTES (name) - 1] == '*')
                from = XLFD_REGISTRY_INDEX, to = XLFD_ENCODING_INDEX,
                  mask = XLFD_REGENC_MASK;
              else
                from = to = XLFD_ENCODING_INDEX,
                  mask = XLFD_ENCODING_MASK;
            }
          else if (range_from <= XLFD_WEIGHT_INDEX
                   && range_to >= XLFD_WEIGHT_INDEX
                   && FONT_WEIGHT_NAME_NUMERIC (val) >= 0)
            from = to = XLFD_WEIGHT_INDEX, mask = XLFD_WEIGHT_MASK;
          else if (range_from <= XLFD_SLANT_INDEX
                   && range_to >= XLFD_SLANT_INDEX
                   && FONT_SLANT_NAME_NUMERIC (val) >= 0)
            from = to = XLFD_SLANT_INDEX, mask = XLFD_SLANT_MASK;
          else if (range_from <= XLFD_SWIDTH_INDEX
                   && range_to >= XLFD_SWIDTH_INDEX
                   && FONT_WIDTH_NAME_NUMERIC (val) >= 0)
            from = to = XLFD_SWIDTH_INDEX, mask = XLFD_SWIDTH_MASK;
          else
            {
              if (EQ (val, Qc) || EQ (val, Qm) || EQ (val, Qp) || EQ (val, Qd))
                from = to = XLFD_SPACING_INDEX, mask = XLFD_SPACING_MASK;
              else
                from = XLFD_FOUNDRY_INDEX, to = XLFD_ENCODING_INDEX,
                  mask = XLFD_SYMBOL_MASK;
            }

          /* Merge position-based and value-based restrictions.  */
          mask &= range_mask;
          while (from < range_from)
            mask &= ~(1 << from++);
          while (from < 14 && ! (mask & (1 << from)))
            from++;
          while (to > range_to)
            mask &= ~(1 << to--);
          while (to >= 0 && ! (mask & (1 << to)))
            to--;
          if (from > to)
            return -1;
          range[i].from = from;
          range[i].to = to;
          range[i].mask = mask;

          if (from > range_from || to < range_to)
            {
              /* The range is narrowed by value-based restrictions.
                 Reflect it to the other fields.  */

              /* Following fields should be after FROM.  */
              range_from = from;
              /* Preceding fields should be before TO.  */
              for (j = i - 1, from--, to--; j >= 0; j--, from--, to--)
                {
                  /* Check FROM for non-wildcard field.  */
                  if (! NILP (tmp[j]) && range[j].from < from)
                    {
                      while (range[j].from < from)
                        range[j].mask &= ~(1 << range[j].from++);
                      while (from < 14 && ! (range[j].mask & (1 << from)))
                        from++;
                      range[j].from = from;
                    }
                  else
                    from = range[j].from;
                  if (range[j].to > to)
                    {
                      while (range[j].to > to)
                        range[j].mask &= ~(1 << range[j].to--);
                      while (to >= 0 && ! (range[j].mask & (1 << to)))
                        to--;
                      range[j].to = to;
                    }
                  else
                    to = range[j].to;
                  if (from > to)
                    return -1;
                }
            }
        }
    }

  /* Decide all fields from restrictions in RANGE.  */
  for (i = j = 0; i < n ; i++)
    {
      if (j < range[i].from)
        {
          if (i == 0 || ! NILP (tmp[i - 1]))
            /* None of TMP[X] corresponds to Jth field.  */
            return -1;
          memclear (field + j, (range[i].from - j) * word_size);
          j = range[i].from;
        }
      field[j++] = tmp[i];
    }
  if (! NILP (tmp[n - 1]) && j < XLFD_REGISTRY_INDEX)
    return -1;
  memclear (field + j, (XLFD_LAST_INDEX - j) * word_size);
  if (INTEGERP (field[XLFD_ENCODING_INDEX]))
    field[XLFD_ENCODING_INDEX]
      = Fintern (Fnumber_to_string (field[XLFD_ENCODING_INDEX]), Qnil);
  return 0;
}


/* Parse NAME (null terminated) as XLFD and store information in FONT
   (font-spec or font-entity).  Size property of FONT is set as
   follows:
        specified XLFD fields           FONT property
        ---------------------           -------------
        PIXEL_SIZE                      PIXEL_SIZE (Lisp integer)
        POINT_SIZE and RESY             calculated pixel size (Lisp integer)
        POINT_SIZE                      POINT_SIZE/10 (Lisp float)

   If NAME is successfully parsed, return 0.  Otherwise return -1.

   FONT is usually a font-spec, but when this function is called from
   X font backend driver, it is a font-entity.  In that case, NAME is
   a fully specified XLFD.  */

int
font_parse_xlfd (char *name, ptrdiff_t len, Lisp_Object font)
{
  int i, j, n;
  char *f[XLFD_LAST_INDEX + 1];
  Lisp_Object val;
  char *p;

  if (len > 255 || !len)
    /* Maximum XLFD name length is 255. */
    return -1;
  /* Accept "*-.." as a fully specified XLFD. */
  if (name[0] == '*' && (len == 1 || name[1] == '-'))
    i = 1, f[XLFD_FOUNDRY_INDEX] = name;
  else
    i = 0;
  for (p = name + i; *p; p++)
    if (*p == '-')
      {
        f[i++] = p + 1;
        if (i == XLFD_LAST_INDEX)
          break;
      }
  f[i] = name + len;

#define INTERN_FIELD(N) font_intern_prop (f[N], f[(N) + 1] - 1 - f[N], 0)
#define INTERN_FIELD_SYM(N) font_intern_prop (f[N], f[(N) + 1] - 1 - f[N], 1)

  if (i == XLFD_LAST_INDEX)
    {
      /* Fully specified XLFD.  */
      int pixel_size;

      ASET (font, FONT_FOUNDRY_INDEX, INTERN_FIELD_SYM (XLFD_FOUNDRY_INDEX));
      ASET (font, FONT_FAMILY_INDEX, INTERN_FIELD_SYM (XLFD_FAMILY_INDEX));
      for (i = XLFD_WEIGHT_INDEX, j = FONT_WEIGHT_INDEX;
           i <= XLFD_SWIDTH_INDEX; i++, j++)
        {
          val = INTERN_FIELD_SYM (i);
          if (! NILP (val))
            {
              if ((n = font_style_to_value (j, INTERN_FIELD_SYM (i), 0)) < 0)
                return -1;
              ASET (font, j, make_number (n));
            }
        }
      ASET (font, FONT_ADSTYLE_INDEX, INTERN_FIELD_SYM (XLFD_ADSTYLE_INDEX));
      if (strcmp (f[XLFD_REGISTRY_INDEX], "*-*") == 0)
        ASET (font, FONT_REGISTRY_INDEX, Qnil);
      else
        ASET (font, FONT_REGISTRY_INDEX,
              font_intern_prop (f[XLFD_REGISTRY_INDEX],
                                f[XLFD_LAST_INDEX] - f[XLFD_REGISTRY_INDEX],
                                1));
      p = f[XLFD_PIXEL_INDEX];
      if (*p == '[' && (pixel_size = parse_matrix (p)) >= 0)
        ASET (font, FONT_SIZE_INDEX, make_number (pixel_size));
      else
        {
          val = INTERN_FIELD (XLFD_PIXEL_INDEX);
          if (INTEGERP (val))
            ASET (font, FONT_SIZE_INDEX, val);
          else if (FONT_ENTITY_P (font))
            return -1;
          else
            {
              double point_size = -1;

              eassert (FONT_SPEC_P (font));
              p = f[XLFD_POINT_INDEX];
              if (*p == '[')
                point_size = parse_matrix (p);
              else if (c_isdigit (*p))
                point_size = atoi (p), point_size /= 10;
              if (point_size >= 0)
                ASET (font, FONT_SIZE_INDEX, make_float (point_size));
            }
        }

      val = INTERN_FIELD (XLFD_RESY_INDEX);
      if (! NILP (val) && ! INTEGERP (val))
        return -1;
      ASET (font, FONT_DPI_INDEX, val);
      val = INTERN_FIELD (XLFD_SPACING_INDEX);
      if (! NILP (val))
        {
          val = font_prop_validate_spacing (QCspacing, val);
          if (! INTEGERP (val))
            return -1;
          ASET (font, FONT_SPACING_INDEX, val);
        }
      p = f[XLFD_AVGWIDTH_INDEX];
      if (*p == '~')
        p++;
      val = font_intern_prop (p, f[XLFD_REGISTRY_INDEX] - 1 - p, 0);
      if (! NILP (val) && ! INTEGERP (val))
        return -1;
      ASET (font, FONT_AVGWIDTH_INDEX, val);
    }
  else
    {
      bool wild_card_found = 0;
      Lisp_Object prop[XLFD_LAST_INDEX];

      if (FONT_ENTITY_P (font))
        return -1;
      for (j = 0; j < i; j++)
        {
          if (*f[j] == '*')
            {
              if (f[j][1] && f[j][1] != '-')
                return -1;
              prop[j] = Qnil;
              wild_card_found = 1;
            }
          else if (j + 1 < i)
            prop[j] = INTERN_FIELD (j);
          else
            prop[j] = font_intern_prop (f[j], f[i] - f[j], 0);
        }
      if (! wild_card_found)
        return -1;
      if (font_expand_wildcards (prop, i) < 0)
        return -1;

      ASET (font, FONT_FOUNDRY_INDEX, prop[XLFD_FOUNDRY_INDEX]);
      ASET (font, FONT_FAMILY_INDEX, prop[XLFD_FAMILY_INDEX]);
      for (i = XLFD_WEIGHT_INDEX, j = FONT_WEIGHT_INDEX;
           i <= XLFD_SWIDTH_INDEX; i++, j++)
        if (! NILP (prop[i]))
          {
            if ((n = font_style_to_value (j, prop[i], 1)) < 0)
              return -1;
            ASET (font, j, make_number (n));
          }
      ASET (font, FONT_ADSTYLE_INDEX, prop[XLFD_ADSTYLE_INDEX]);
      val = prop[XLFD_REGISTRY_INDEX];
      if (NILP (val))
        {
          val = prop[XLFD_ENCODING_INDEX];
          if (! NILP (val))
            {
              AUTO_STRING (star_dash, "*-");
              val = concat2 (star_dash, SYMBOL_NAME (val));
            }
        }
      else if (NILP (prop[XLFD_ENCODING_INDEX]))
        {
          AUTO_STRING (dash_star, "-*");
          val = concat2 (SYMBOL_NAME (val), dash_star);
        }
      else
        {
          AUTO_STRING (dash, "-");
          val = concat3 (SYMBOL_NAME (val), dash,
                         SYMBOL_NAME (prop[XLFD_ENCODING_INDEX]));
        }
      if (! NILP (val))
        ASET (font, FONT_REGISTRY_INDEX, Fintern (val, Qnil));

      if (INTEGERP (prop[XLFD_PIXEL_INDEX]))
        ASET (font, FONT_SIZE_INDEX, prop[XLFD_PIXEL_INDEX]);
      else if (INTEGERP (prop[XLFD_POINT_INDEX]))
        {
          double point_size = XINT (prop[XLFD_POINT_INDEX]);

          ASET (font, FONT_SIZE_INDEX, make_float (point_size / 10));
        }

      if (INTEGERP (prop[XLFD_RESX_INDEX]))
        ASET (font, FONT_DPI_INDEX, prop[XLFD_RESY_INDEX]);
      if (! NILP (prop[XLFD_SPACING_INDEX]))
        {
          val = font_prop_validate_spacing (QCspacing,
                                            prop[XLFD_SPACING_INDEX]);
          if (! INTEGERP (val))
            return -1;
          ASET (font, FONT_SPACING_INDEX, val);
        }
      if (INTEGERP (prop[XLFD_AVGWIDTH_INDEX]))
        ASET (font, FONT_AVGWIDTH_INDEX, prop[XLFD_AVGWIDTH_INDEX]);
    }

  return 0;
}

/* Store XLFD name of FONT (font-spec or font-entity) in NAME (NBYTES
   length), and return the name length.  If FONT_SIZE_INDEX of FONT is
   0, use PIXEL_SIZE instead.  */

ptrdiff_t
font_unparse_xlfd (Lisp_Object font, int pixel_size, char *name, int nbytes)
{
  char *p;
  const char *f[XLFD_REGISTRY_INDEX + 1];
  Lisp_Object val;
  int i, j, len;

  eassert (FONTP (font));

  for (i = FONT_FOUNDRY_INDEX, j = XLFD_FOUNDRY_INDEX; i <= FONT_REGISTRY_INDEX;
       i++, j++)
    {
      if (i == FONT_ADSTYLE_INDEX)
        j = XLFD_ADSTYLE_INDEX;
      else if (i == FONT_REGISTRY_INDEX)
        j = XLFD_REGISTRY_INDEX;
      val = AREF (font, i);
      if (NILP (val))
        {
          if (j == XLFD_REGISTRY_INDEX)
            f[j] = "*-*";
          else
            f[j] = "*";
        }
      else
        {
          if (SYMBOLP (val))
            val = SYMBOL_NAME (val);
          if (j == XLFD_REGISTRY_INDEX
              && ! strchr (SSDATA (val), '-'))
            {
              /* Change "jisx0208*" and "jisx0208" to "jisx0208*-*".  */
              ptrdiff_t alloc = SBYTES (val) + 4;
              if (nbytes <= alloc)
                return -1;
              f[j] = p = alloca (alloc);
              sprintf (p, "%s%s-*", SDATA (val),
                       &"*"[SDATA (val)[SBYTES (val) - 1] == '*']);
            }
          else
            f[j] = SSDATA (val);
        }
    }

  for (i = FONT_WEIGHT_INDEX, j = XLFD_WEIGHT_INDEX; i <= FONT_WIDTH_INDEX;
       i++, j++)
    {
      val = font_style_symbolic (font, i, 0);
      if (NILP (val))
        f[j] = "*";
      else
        {
          int c, k, l;
          ptrdiff_t alloc;

          val = SYMBOL_NAME (val);
          alloc = SBYTES (val) + 1;
          if (nbytes <= alloc)
            return -1;
          f[j] = p = alloca (alloc);
          /* Copy the name while excluding '-', '?', ',', and '"'.  */
          for (k = l = 0; k < alloc; k++)
            {
              c = SREF (val, k);
              if (c != '-' && c != '?' && c != ',' && c != '"')
                p[l++] = c;
            }
        }
    }

  val = AREF (font, FONT_SIZE_INDEX);
  eassert (NUMBERP (val) || NILP (val));
  char font_size_index_buf[sizeof "-*"
                           + max (INT_STRLEN_BOUND (EMACS_INT),
                                  1 + DBL_MAX_10_EXP + 1)];
  if (INTEGERP (val))
    {
      EMACS_INT v = XINT (val);
      if (v <= 0)
        v = pixel_size;
      if (v > 0)
        {
          f[XLFD_PIXEL_INDEX] = p = font_size_index_buf;
          sprintf (p, "%"pI"d-*", v);
        }
      else
        f[XLFD_PIXEL_INDEX] = "*-*";
    }
  else if (FLOATP (val))
    {
      double v = XFLOAT_DATA (val) * 10;
      f[XLFD_PIXEL_INDEX] = p = font_size_index_buf;
      sprintf (p, "*-%.0f", v);
    }
  else
    f[XLFD_PIXEL_INDEX] = "*-*";

  char dpi_index_buf[sizeof "-" + 2 * INT_STRLEN_BOUND (EMACS_INT)];
  if (INTEGERP (AREF (font, FONT_DPI_INDEX)))
    {
      EMACS_INT v = XINT (AREF (font, FONT_DPI_INDEX));
      f[XLFD_RESX_INDEX] = p = dpi_index_buf;
      sprintf (p, "%"pI"d-%"pI"d", v, v);
    }
  else
    f[XLFD_RESX_INDEX] = "*-*";

  if (INTEGERP (AREF (font, FONT_SPACING_INDEX)))
    {
      EMACS_INT spacing = XINT (AREF (font, FONT_SPACING_INDEX));

      f[XLFD_SPACING_INDEX] = (spacing <= FONT_SPACING_PROPORTIONAL ? "p"
                               : spacing <= FONT_SPACING_DUAL ? "d"
                               : spacing <= FONT_SPACING_MONO ? "m"
                               : "c");
    }
  else
    f[XLFD_SPACING_INDEX] = "*";

  char avgwidth_index_buf[INT_BUFSIZE_BOUND (EMACS_INT)];
  if (INTEGERP (AREF (font,  FONT_AVGWIDTH_INDEX)))
    {
      f[XLFD_AVGWIDTH_INDEX] = p = avgwidth_index_buf;
      sprintf (p, "%"pI"d", XINT (AREF (font, FONT_AVGWIDTH_INDEX)));
    }
  else
    f[XLFD_AVGWIDTH_INDEX] = "*";

  len = snprintf (name, nbytes, "-%s-%s-%s-%s-%s-%s-%s-%s-%s-%s-%s",
                  f[XLFD_FOUNDRY_INDEX], f[XLFD_FAMILY_INDEX],
                  f[XLFD_WEIGHT_INDEX], f[XLFD_SLANT_INDEX],
                  f[XLFD_SWIDTH_INDEX], f[XLFD_ADSTYLE_INDEX],
                  f[XLFD_PIXEL_INDEX], f[XLFD_RESX_INDEX],
                  f[XLFD_SPACING_INDEX], f[XLFD_AVGWIDTH_INDEX],
                  f[XLFD_REGISTRY_INDEX]);
  return len < nbytes ? len : -1;
}

/* Parse NAME (null terminated) and store information in FONT
   (font-spec or font-entity).  NAME is supplied in either the
   Fontconfig or GTK font name format.  If NAME is successfully
   parsed, return 0.  Otherwise return -1.

   The fontconfig format is

    FAMILY[-SIZE][:PROP1[=VAL1][:PROP2[=VAL2]...]]

   The GTK format is

    FAMILY [PROPS...] [SIZE]

   This function tries to guess which format it is.  */

static int
font_parse_fcname (char *name, ptrdiff_t len, Lisp_Object font)
{
  char *p, *q;
  char *size_beg = NULL, *size_end = NULL;
  char *props_beg = NULL, *family_end = NULL;

  if (len == 0)
    return -1;

  for (p = name; *p; p++)
    {
      if (*p == '\\' && p[1])
        p++;
      else if (*p == ':')
        {
          props_beg = family_end = p;
          break;
        }
      else if (*p == '-')
        {
          bool decimal = 0, size_found = 1;
          for (q = p + 1; *q && *q != ':'; q++)
            if (! c_isdigit (*q))
              {
                if (*q != '.' || decimal)
                  {
                    size_found = 0;
                    break;
                  }
                decimal = 1;
              }
          if (size_found)
            {
              family_end = p;
              size_beg = p + 1;
              size_end = q;
              break;
            }
        }
    }

  if (family_end)
    {
      Lisp_Object extra_props = Qnil;

      /* A fontconfig name with size and/or property data.  */
      if (family_end > name)
        {
          Lisp_Object family;
          family = font_intern_prop (name, family_end - name, 1);
          ASET (font, FONT_FAMILY_INDEX, family);
        }
      if (size_beg)
        {
          double point_size = strtod (size_beg, &size_end);
          ASET (font, FONT_SIZE_INDEX, make_float (point_size));
          if (*size_end == ':' && size_end[1])
            props_beg = size_end;
        }
      if (props_beg)
        {
          /* Now parse ":KEY=VAL" patterns.  */
          Lisp_Object val;

          for (p = props_beg; *p; p = q)
            {
              for (q = p + 1; *q && *q != '=' && *q != ':'; q++);
              if (*q != '=')
                {
                  /* Must be an enumerated value.  */
                  ptrdiff_t word_len;
                  p = p + 1;
                  word_len = q - p;
                  val = font_intern_prop (p, q - p, 1);

#define PROP_MATCH(STR) (word_len == strlen (STR)               \
                         && memcmp (p, STR, strlen (STR)) == 0)

                  if (PROP_MATCH ("light")
                      || PROP_MATCH ("medium")
                      || PROP_MATCH ("demibold")
                      || PROP_MATCH ("bold")
                      || PROP_MATCH ("black"))
                    FONT_SET_STYLE (font, FONT_WEIGHT_INDEX, val);
                  else if (PROP_MATCH ("roman")
                           || PROP_MATCH ("italic")
                           || PROP_MATCH ("oblique"))
                    FONT_SET_STYLE (font, FONT_SLANT_INDEX, val);
                  else if (PROP_MATCH ("charcell"))
                    ASET (font, FONT_SPACING_INDEX,
                          make_number (FONT_SPACING_CHARCELL));
                  else if (PROP_MATCH ("mono"))
                    ASET (font, FONT_SPACING_INDEX,
                          make_number (FONT_SPACING_MONO));
                  else if (PROP_MATCH ("proportional"))
                    ASET (font, FONT_SPACING_INDEX,
                          make_number (FONT_SPACING_PROPORTIONAL));
#undef PROP_MATCH
                }
              else
                {
                  /* KEY=VAL pairs  */
                  Lisp_Object key;
                  int prop;

                  if (q - p == 10 && memcmp (p + 1, "pixelsize", 9) == 0)
                    prop = FONT_SIZE_INDEX;
                  else
                    {
                      key = font_intern_prop (p, q - p, 1);
                      prop = get_font_prop_index (key);
                    }

                  p = q + 1;
                  for (q = p; *q && *q != ':'; q++);
                  val = font_intern_prop (p, q - p, 0);

                  if (prop >= FONT_FOUNDRY_INDEX
                      && prop < FONT_EXTRA_INDEX)
                    ASET (font, prop, font_prop_validate (prop, Qnil, val));
                  else
                    {
                      extra_props = nconc2 (extra_props,
                                            list1 (Fcons (key, val)));
                    }
                }
              p = q;
            }
        }

      if (! NILP (extra_props))
        {
          struct font_driver_list *driver_list = font_driver_list;
          for ( ; driver_list; driver_list = driver_list->next)
            if (driver_list->driver->filter_properties)
              (*driver_list->driver->filter_properties) (font, extra_props);
        }

    }
  else
    {
      /* Either a fontconfig-style name with no size and property
         data, or a GTK-style name.  */
      Lisp_Object weight = Qnil, slant = Qnil;
      Lisp_Object width  = Qnil, size  = Qnil;
      char *word_start;
      ptrdiff_t word_len;

      /* Scan backwards from the end, looking for a size.  */
      for (p = name + len - 1; p >= name; p--)
        if (!c_isdigit (*p))
          break;

      if ((p < name + len - 1) && ((p + 1 == name) || *p == ' '))
        /* Found a font size.  */
        size = make_float (strtod (p + 1, NULL));
      else
        p = name + len;

      /* Now P points to the termination of the string, sans size.
         Scan backwards, looking for font properties.  */
      for (; p > name; p = q)
        {
          for (q = p - 1; q >= name; q--)
            {
              if (q > name && *(q-1) == '\\')
                --q;   /* Skip quoting backslashes.  */
              else if (*q == ' ')
                break;
            }

          word_start = q + 1;
          word_len = p - word_start;

#define PROP_MATCH(STR)                                         \
          (word_len == strlen (STR)                             \
           && memcmp (word_start, STR, strlen (STR)) == 0)
#define PROP_SAVE(VAR, STR)                                     \
          (VAR = NILP (VAR) ? font_intern_prop (STR, strlen (STR), 1) : VAR)

          if (PROP_MATCH ("Ultra-Light"))
            PROP_SAVE (weight, "ultra-light");
          else if (PROP_MATCH ("Light"))
            PROP_SAVE (weight, "light");
          else if (PROP_MATCH ("Book"))
            PROP_SAVE (weight, "book");
          else if (PROP_MATCH ("Medium"))
            PROP_SAVE (weight, "medium");
          else if (PROP_MATCH ("Semi-Bold"))
            PROP_SAVE (weight, "semi-bold");
          else if (PROP_MATCH ("Bold"))
            PROP_SAVE (weight, "bold");
          else if (PROP_MATCH ("Italic"))
            PROP_SAVE (slant, "italic");
          else if (PROP_MATCH ("Oblique"))
            PROP_SAVE (slant, "oblique");
          else if (PROP_MATCH ("Semi-Condensed"))
            PROP_SAVE (width, "semi-condensed");
          else if (PROP_MATCH ("Condensed"))
            PROP_SAVE (width, "condensed");
          /* An unknown word must be part of the font name.  */
          else
            {
              family_end = p;
              break;
            }
        }
#undef PROP_MATCH
#undef PROP_SAVE

      if (family_end)
        ASET (font, FONT_FAMILY_INDEX,
              font_intern_prop (name, family_end - name, 1));
      if (!NILP (size))
        ASET (font, FONT_SIZE_INDEX, size);
      if (!NILP (weight))
        FONT_SET_STYLE (font, FONT_WEIGHT_INDEX, weight);
      if (!NILP (slant))
        FONT_SET_STYLE (font, FONT_SLANT_INDEX, slant);
      if (!NILP (width))
        FONT_SET_STYLE (font, FONT_WIDTH_INDEX, width);
    }

  return 0;
}

#if defined HAVE_XFT || defined HAVE_FREETYPE || defined HAVE_NS

/* Store fontconfig's font name of FONT (font-spec or font-entity) in
   NAME (NBYTES length), and return the name length.  If
   FONT_SIZE_INDEX of FONT is 0, use PIXEL_SIZE instead.
   Return a negative value on error.  */

static int
font_unparse_fcname (Lisp_Object font, int pixel_size, char *name, int nbytes)
{
  Lisp_Object family, foundry;
  Lisp_Object val;
  int point_size;
  int i;
  char *p;
  char *lim;
  Lisp_Object styles[3];
  const char *style_names[3] = { "weight", "slant", "width" };

  family = AREF (font, FONT_FAMILY_INDEX);
  if (! NILP (family))
    {
      if (SYMBOLP (family))
        family = SYMBOL_NAME (family);
      else
        family = Qnil;
    }

  val = AREF (font, FONT_SIZE_INDEX);
  if (INTEGERP (val))
    {
      if (XINT (val) != 0)
        pixel_size = XINT (val);
      point_size = -1;
    }
  else
    {
      eassert (FLOATP (val));
      pixel_size = -1;
      point_size = (int) XFLOAT_DATA (val);
    }

  foundry = AREF (font, FONT_FOUNDRY_INDEX);
  if (! NILP (foundry))
    {
      if (SYMBOLP (foundry))
        foundry = SYMBOL_NAME (foundry);
      else
        foundry = Qnil;
    }

  for (i = 0; i < 3; i++)
    styles[i] = font_style_symbolic (font, FONT_WEIGHT_INDEX + i, 0);

  p = name;
  lim = name + nbytes;
  if (! NILP (family))
    {
      int len = snprintf (p, lim - p, "%s", SSDATA (family));
      if (! (0 <= len && len < lim - p))
        return -1;
      p += len;
    }
  if (point_size > 0)
    {
      int len = snprintf (p, lim - p, &"-%d"[p == name], point_size);
      if (! (0 <= len && len < lim - p))
        return -1;
      p += len;
    }
  else if (pixel_size > 0)
    {
      int len = snprintf (p, lim - p, ":pixelsize=%d", pixel_size);
      if (! (0 <= len && len < lim - p))
        return -1;
      p += len;
    }
  if (! NILP (AREF (font, FONT_FOUNDRY_INDEX)))
    {
      int len = snprintf (p, lim - p, ":foundry=%s",
                          SSDATA (SYMBOL_NAME (AREF (font,
                                                     FONT_FOUNDRY_INDEX))));
      if (! (0 <= len && len < lim - p))
        return -1;
      p += len;
    }
  for (i = 0; i < 3; i++)
    if (! NILP (styles[i]))
      {
        int len = snprintf (p, lim - p, ":%s=%s", style_names[i],
                            SSDATA (SYMBOL_NAME (styles[i])));
        if (! (0 <= len && len < lim - p))
          return -1;
        p += len;
      }

  if (INTEGERP (AREF (font, FONT_DPI_INDEX)))
    {
      int len = snprintf (p, lim - p, ":dpi=%"pI"d",
                          XINT (AREF (font, FONT_DPI_INDEX)));
      if (! (0 <= len && len < lim - p))
        return -1;
      p += len;
    }

  if (INTEGERP (AREF (font, FONT_SPACING_INDEX)))
    {
      int len = snprintf (p, lim - p, ":spacing=%"pI"d",
                          XINT (AREF (font, FONT_SPACING_INDEX)));
      if (! (0 <= len && len < lim - p))
        return -1;
      p += len;
    }

  if (INTEGERP (AREF (font, FONT_AVGWIDTH_INDEX)))
    {
      int len = snprintf (p, lim - p,
                          (XINT (AREF (font, FONT_AVGWIDTH_INDEX)) == 0
                           ? ":scalable=true"
                           : ":scalable=false"));
      if (! (0 <= len && len < lim - p))
        return -1;
      p += len;
    }

  return (p - name);
}

#endif

/* Parse NAME (null terminated) and store information in FONT
   (font-spec or font-entity).  If NAME is successfully parsed, return
   0.  Otherwise return -1.  */

static int
font_parse_name (char *name, ptrdiff_t namelen, Lisp_Object font)
{
  if (name[0] == '-' || strchr (name, '*') || strchr (name, '?'))
    return font_parse_xlfd (name, namelen, font);
  return font_parse_fcname (name, namelen, font);
}


/* Merge FAMILY and REGISTRY into FONT_SPEC.  FAMILY may have the form
   "FAMILY-FOUNDRY".  REGISTRY may not contain charset-encoding
   part.  */

void
font_parse_family_registry (Lisp_Object family, Lisp_Object registry, Lisp_Object font_spec)
{
  ptrdiff_t len;
  char *p0, *p1;

  if (! NILP (family)
      && NILP (AREF (font_spec, FONT_FAMILY_INDEX)))
    {
      CHECK_STRING (family);
      len = SBYTES (family);
      p0 = SSDATA (family);
      p1 = strchr (p0, '-');
      if (p1)
        {
          if ((*p0 != '*' && p1 - p0 > 0)
              && NILP (AREF (font_spec, FONT_FOUNDRY_INDEX)))
            Ffont_put (font_spec, QCfoundry, font_intern_prop (p0, p1 - p0, 1));
          p1++;
          len -= p1 - p0;
          Ffont_put (font_spec, QCfamily, font_intern_prop (p1, len, 1));
        }
      else
        ASET (font_spec, FONT_FAMILY_INDEX, Fintern (family, Qnil));
    }
  if (! NILP (registry))
    {
      /* Convert "XXX" and "XXX*" to "XXX*-*".  */
      CHECK_STRING (registry);
      len = SBYTES (registry);
      p0 = SSDATA (registry);
      p1 = strchr (p0, '-');
      if (! p1)
        {
          bool asterisk = len && p0[len - 1] == '*';
          AUTO_STRING_WITH_LEN (extra, &"*-*"[asterisk], 3 - asterisk);
          registry = concat2 (registry, extra);
        }
      registry = Fdowncase (registry);
      ASET (font_spec, FONT_REGISTRY_INDEX, Fintern (registry, Qnil));
    }
}

\f
/* This part (through the next ^L) is still experimental and not
   tested much.  We may drastically change codes.  */

/* OTF handler.  */

#if 0

#define LGSTRING_HEADER_SIZE 6
#define LGSTRING_GLYPH_SIZE 8

static int
check_gstring (Lisp_Object gstring)
{
  Lisp_Object val;
  ptrdiff_t i;
  int j;

  CHECK_VECTOR (gstring);
  val = AREF (gstring, 0);
  CHECK_VECTOR (val);
  if (ASIZE (val) < LGSTRING_HEADER_SIZE)
    goto err;
  CHECK_FONT_OBJECT (LGSTRING_FONT (gstring));
  if (!NILP (LGSTRING_SLOT (gstring, LGSTRING_IX_LBEARING)))
    CHECK_NUMBER (LGSTRING_SLOT (gstring, LGSTRING_IX_LBEARING));
  if (!NILP (LGSTRING_SLOT (gstring, LGSTRING_IX_RBEARING)))
    CHECK_NUMBER (LGSTRING_SLOT (gstring, LGSTRING_IX_RBEARING));
  if (!NILP (LGSTRING_SLOT (gstring, LGSTRING_IX_WIDTH)))
    CHECK_NATNUM (LGSTRING_SLOT (gstring, LGSTRING_IX_WIDTH));
  if (!NILP (LGSTRING_SLOT (gstring, LGSTRING_IX_ASCENT)))
    CHECK_NUMBER (LGSTRING_SLOT (gstring, LGSTRING_IX_ASCENT));
  if (!NILP (LGSTRING_SLOT (gstring, LGSTRING_IX_ASCENT)))
    CHECK_NUMBER (LGSTRING_SLOT (gstring, LGSTRING_IX_ASCENT));

  for (i = 0; i < LGSTRING_GLYPH_LEN (gstring); i++)
    {
      val = LGSTRING_GLYPH (gstring, i);
      CHECK_VECTOR (val);
      if (ASIZE (val) < LGSTRING_GLYPH_SIZE)
        goto err;
      if (NILP (AREF (val, LGLYPH_IX_CHAR)))
        break;
      CHECK_NATNUM (AREF (val, LGLYPH_IX_FROM));
      CHECK_NATNUM (AREF (val, LGLYPH_IX_TO));
      CHECK_CHARACTER (AREF (val, LGLYPH_IX_CHAR));
      if (!NILP (AREF (val, LGLYPH_IX_CODE)))
        CHECK_NATNUM (AREF (val, LGLYPH_IX_CODE));
      if (!NILP (AREF (val, LGLYPH_IX_WIDTH)))
        CHECK_NATNUM (AREF (val, LGLYPH_IX_WIDTH));
      if (!NILP (AREF (val, LGLYPH_IX_ADJUSTMENT)))
        {
          val = AREF (val, LGLYPH_IX_ADJUSTMENT);
          CHECK_VECTOR (val);
          if (ASIZE (val) < 3)
            goto err;
          for (j = 0; j < 3; j++)
            CHECK_NUMBER (AREF (val, j));
        }
    }
  return i;
 err:
  error ("Invalid glyph-string format");
  return -1;
}

static void
check_otf_features (Lisp_Object otf_features)
{
  Lisp_Object val;

  CHECK_CONS (otf_features);
  CHECK_SYMBOL (XCAR (otf_features));
  otf_features = XCDR (otf_features);
  CHECK_CONS (otf_features);
  CHECK_SYMBOL (XCAR (otf_features));
  otf_features = XCDR (otf_features);
  for (val = Fcar (otf_features); CONSP (val); val = XCDR (val))
    {
      CHECK_SYMBOL (XCAR (val));
      if (SBYTES (SYMBOL_NAME (XCAR (val))) > 4)
        error ("Invalid OTF GSUB feature: %s",
               SDATA (SYMBOL_NAME (XCAR (val))));
    }
  otf_features = XCDR (otf_features);
  for (val = Fcar (otf_features); CONSP (val); val = XCDR (val))
    {
      CHECK_SYMBOL (XCAR (val));
      if (SBYTES (SYMBOL_NAME (XCAR (val))) > 4)
        error ("Invalid OTF GPOS feature: %s",
               SDATA (SYMBOL_NAME (XCAR (val))));
    }
}

#ifdef HAVE_LIBOTF
#include <otf.h>

Lisp_Object otf_list;

static Lisp_Object
otf_tag_symbol (OTF_Tag tag)
{
  char name[5];

  OTF_tag_name (tag, name);
  return Fintern (make_unibyte_string (name, 4), Qnil);
}

static OTF *
otf_open (Lisp_Object file)
{
  Lisp_Object val = Fassoc (file, otf_list, Qnil);
  OTF *otf;

  if (! NILP (val))
    otf = XSAVE_POINTER (XCDR (val), 0);
  else
    {
      otf = STRINGP (file) ? OTF_open (SSDATA (file)) : NULL;
      val = make_save_ptr (otf);
      otf_list = Fcons (Fcons (file, val), otf_list);
    }
  return otf;
}


/* Return a list describing which scripts/languages FONT supports by
   which GSUB/GPOS features of OpenType tables.  See the comment of
   (struct font_driver).otf_capability.  */

Lisp_Object
font_otf_capability (struct font *font)
{
  OTF *otf;
  Lisp_Object capability = Fcons (Qnil, Qnil);
  int i;

  otf = otf_open (font->props[FONT_FILE_INDEX]);
  if (! otf)
    return Qnil;
  for (i = 0; i < 2; i++)
    {
      OTF_GSUB_GPOS *gsub_gpos;
      Lisp_Object script_list = Qnil;
      int j;

      if (OTF_get_features (otf, i == 0) < 0)
        continue;
      gsub_gpos = i == 0 ? otf->gsub : otf->gpos;
      for (j = gsub_gpos->ScriptList.ScriptCount - 1; j >= 0; j--)
        {
          OTF_Script *script = gsub_gpos->ScriptList.Script + j;
          Lisp_Object langsys_list = Qnil;
          Lisp_Object script_tag = otf_tag_symbol (script->ScriptTag);
          int k;

          for (k = script->LangSysCount; k >= 0; k--)
            {
              OTF_LangSys *langsys;
              Lisp_Object feature_list = Qnil;
              Lisp_Object langsys_tag;
              int l;

              if (k == script->LangSysCount)
                {
                  langsys = &script->DefaultLangSys;
                  langsys_tag = Qnil;
                }
              else
                {
                  langsys = script->LangSys + k;
                  langsys_tag
                    = otf_tag_symbol (script->LangSysRecord[k].LangSysTag);
                }
              for (l = langsys->FeatureCount - 1; l >= 0; l--)
                {
                  OTF_Feature *feature
                    = gsub_gpos->FeatureList.Feature + langsys->FeatureIndex[l];
                  Lisp_Object feature_tag
                    = otf_tag_symbol (feature->FeatureTag);

                  feature_list = Fcons (feature_tag, feature_list);
                }
              langsys_list = Fcons (Fcons (langsys_tag, feature_list),
                                    langsys_list);
            }
          script_list = Fcons (Fcons (script_tag, langsys_list),
                               script_list);
        }

      if (i == 0)
        XSETCAR (capability, script_list);
      else
        XSETCDR (capability, script_list);
    }

  return capability;
}

/* Parse OTF features in SPEC and write a proper features spec string
   in FEATURES for the call of OTF_drive_gsub/gpos (of libotf).  It is
   assured that the sufficient memory has already allocated for
   FEATURES.  */

static void
generate_otf_features (Lisp_Object spec, char *features)
{
  Lisp_Object val;
  char *p;
  bool asterisk;

  p = features;
  *p = '\0';
  for (asterisk = 0; CONSP (spec); spec = XCDR (spec))
    {
      val = XCAR (spec);
      CHECK_SYMBOL (val);
      if (p > features)
        *p++ = ',';
      if (SREF (SYMBOL_NAME (val), 0) == '*')
        {
          asterisk = 1;
          *p++ = '*';
        }
      else if (! asterisk)
        {
          val = SYMBOL_NAME (val);
          p += esprintf (p, "%s", SDATA (val));
        }
      else
        {
          val = SYMBOL_NAME (val);
          p += esprintf (p, "~%s", SDATA (val));
        }
    }
  if (CONSP (spec))
    error ("OTF spec too long");
}

Lisp_Object
font_otf_DeviceTable (OTF_DeviceTable *device_table)
{
  int len = device_table->StartSize - device_table->EndSize + 1;

  return Fcons (make_number (len),
                make_unibyte_string (device_table->DeltaValue, len));
}

Lisp_Object
font_otf_ValueRecord (int value_format, OTF_ValueRecord *value_record)
{
  Lisp_Object val = Fmake_vector (make_number (8), Qnil);

  if (value_format & OTF_XPlacement)
    ASET (val, 0, make_number (value_record->XPlacement));
  if (value_format & OTF_YPlacement)
    ASET (val, 1, make_number (value_record->YPlacement));
  if (value_format & OTF_XAdvance)
    ASET (val, 2, make_number (value_record->XAdvance));
  if (value_format & OTF_YAdvance)
    ASET (val, 3, make_number (value_record->YAdvance));
  if (value_format & OTF_XPlaDevice)
    ASET (val, 4, font_otf_DeviceTable (&value_record->XPlaDevice));
  if (value_format & OTF_YPlaDevice)
    ASET (val, 4, font_otf_DeviceTable (&value_record->YPlaDevice));
  if (value_format & OTF_XAdvDevice)
    ASET (val, 4, font_otf_DeviceTable (&value_record->XAdvDevice));
  if (value_format & OTF_YAdvDevice)
    ASET (val, 4, font_otf_DeviceTable (&value_record->YAdvDevice));
  return val;
}

Lisp_Object
font_otf_Anchor (OTF_Anchor *anchor)
{
  Lisp_Object val;

  val = Fmake_vector (make_number (anchor->AnchorFormat + 1), Qnil);
  ASET (val, 0, make_number (anchor->XCoordinate));
  ASET (val, 1, make_number (anchor->YCoordinate));
  if (anchor->AnchorFormat == 2)
    ASET (val, 2, make_number (anchor->f.f1.AnchorPoint));
  else
    {
      ASET (val, 3, font_otf_DeviceTable (&anchor->f.f2.XDeviceTable));
      ASET (val, 4, font_otf_DeviceTable (&anchor->f.f2.YDeviceTable));
    }
  return val;
}
#endif  /* HAVE_LIBOTF */
#endif  /* 0 */

\f
/* Font sorting.  */

static double
font_rescale_ratio (Lisp_Object font_entity)
{
  Lisp_Object tail, elt;
  Lisp_Object name = Qnil;

  for (tail = Vface_font_rescale_alist; CONSP (tail); tail = XCDR (tail))
    {
      elt = XCAR (tail);
      if (FLOATP (XCDR (elt)))
        {
          if (STRINGP (XCAR (elt)))
            {
              if (NILP (name))
                name = Ffont_xlfd_name (font_entity, Qnil);
              if (fast_string_match_ignore_case (XCAR (elt), name) >= 0)
                return XFLOAT_DATA (XCDR (elt));
            }
          else if (FONT_SPEC_P (XCAR (elt)))
            {
              if (font_match_p (XCAR (elt), font_entity))
                return XFLOAT_DATA (XCDR (elt));
            }
        }
    }
  return 1.0;
}

/* We sort fonts by scoring each of them against a specified
   font-spec.  The score value is 32 bit (`unsigned'), and the smaller
   the value is, the closer the font is to the font-spec.

   The lowest 2 bits of the score are used for driver type.  The font
   available by the most preferred font driver is 0.

   The 4 7-bit fields in the higher 28 bits are used for numeric properties
   WEIGHT, SLANT, WIDTH, and SIZE.  */

/* How many bits to shift to store the difference value of each font
   property in a score.  Note that floats for FONT_TYPE_INDEX and
   FONT_REGISTRY_INDEX are not used.  */
static int sort_shift_bits[FONT_SIZE_INDEX + 1];

/* Score font-entity ENTITY against properties of font-spec SPEC_PROP.
   The return value indicates how different ENTITY is compared with
   SPEC_PROP.  */

static unsigned
font_score (Lisp_Object entity, Lisp_Object *spec_prop)
{
  unsigned score = 0;
  int i;

  /* Score three style numeric fields.  Maximum difference is 127. */
  for (i = FONT_WEIGHT_INDEX; i <= FONT_WIDTH_INDEX; i++)
    if (! NILP (spec_prop[i]) && ! EQ (AREF (entity, i), spec_prop[i]))
      {
        EMACS_INT diff = ((XINT (AREF (entity, i)) >> 8)
                          - (XINT (spec_prop[i]) >> 8));
        score |= min (eabs (diff), 127) << sort_shift_bits[i];
      }

  /* Score the size.  Maximum difference is 127.  */
  if (! NILP (spec_prop[FONT_SIZE_INDEX])
      && XINT (AREF (entity, FONT_SIZE_INDEX)) > 0)
    {
      /* We use the higher 6-bit for the actual size difference.  The
         lowest bit is set if the DPI is different.  */
      EMACS_INT diff;
      EMACS_INT pixel_size = XINT (spec_prop[FONT_SIZE_INDEX]);
      EMACS_INT entity_size = XINT (AREF (entity, FONT_SIZE_INDEX));

      if (CONSP (Vface_font_rescale_alist))
        pixel_size *= font_rescale_ratio (entity);
      if (pixel_size * 2 < entity_size || entity_size * 2 < pixel_size)
        /* This size is wrong by more than a factor 2: reject it!  */
        return 0xFFFFFFFF;
      diff = eabs (pixel_size - entity_size) << 1;
      if (! NILP (spec_prop[FONT_DPI_INDEX])
          && ! EQ (spec_prop[FONT_DPI_INDEX], AREF (entity, FONT_DPI_INDEX)))
        diff |= 1;
      if (! NILP (spec_prop[FONT_AVGWIDTH_INDEX])
          && ! EQ (spec_prop[FONT_AVGWIDTH_INDEX], AREF (entity, FONT_AVGWIDTH_INDEX)))
        diff |= 1;
      score |= min (diff, 127) << sort_shift_bits[FONT_SIZE_INDEX];
    }

  return score;
}


/* Concatenate all elements of LIST into one vector.  LIST is a list
   of font-entity vectors.  */

static Lisp_Object
font_vconcat_entity_vectors (Lisp_Object list)
{
  EMACS_INT nargs = XFASTINT (Flength (list));
  Lisp_Object *args;
  USE_SAFE_ALLOCA;
  SAFE_ALLOCA_LISP (args, nargs);
  ptrdiff_t i;

  for (i = 0; i < nargs; i++, list = XCDR (list))
    args[i] = XCAR (list);
  Lisp_Object result = Fvconcat (nargs, args);
  SAFE_FREE ();
  return result;
}


/* The structure for elements being sorted by qsort.  */
struct font_sort_data
{
  unsigned score;
  int font_driver_preference;
  Lisp_Object entity;
};


/* The comparison function for qsort.  */

static int
font_compare (const void *d1, const void *d2)
{
  const struct font_sort_data *data1 = d1;
  const struct font_sort_data *data2 = d2;

  if (data1->score < data2->score)
    return -1;
  else if (data1->score > data2->score)
    return 1;
  return (data1->font_driver_preference - data2->font_driver_preference);
}


/* Sort each font-entity vector in LIST by closeness to font-spec PREFER.
   If PREFER specifies a point-size, calculate the corresponding
   pixel-size from QCdpi property of PREFER or from the Y-resolution
   of FRAME before sorting.

   If BEST-ONLY is nonzero, return the best matching entity (that
   supports the character BEST-ONLY if BEST-ONLY is positive, or any
   if BEST-ONLY is negative).  Otherwise, return the sorted result as
   a single vector of font-entities.

   This function does no optimization for the case that the total
   number of elements is 1.  The caller should avoid calling this in
   such a case.  */

static Lisp_Object
font_sort_entities (Lisp_Object list, Lisp_Object prefer,
                    struct frame *f, int best_only)
{
  Lisp_Object prefer_prop[FONT_SPEC_MAX];
  int len, maxlen, i;
  struct font_sort_data *data;
  unsigned best_score;
  Lisp_Object best_entity;
  Lisp_Object tail;
  Lisp_Object vec UNINIT;
  USE_SAFE_ALLOCA;

  for (i = FONT_WEIGHT_INDEX; i <= FONT_AVGWIDTH_INDEX; i++)
    prefer_prop[i] = AREF (prefer, i);
  if (FLOATP (prefer_prop[FONT_SIZE_INDEX]))
    prefer_prop[FONT_SIZE_INDEX]
      = make_number (font_pixel_size (f, prefer));

  if (NILP (XCDR (list)))
    {
      /* What we have to take care of is this single vector.  */
      vec = XCAR (list);
      maxlen = ASIZE (vec);
    }
  else if (best_only)
    {
      /* We don't have to perform sort, so there's no need of creating
         a single vector.  But, we must find the length of the longest
         vector.  */
      maxlen = 0;
      for (tail = list; CONSP (tail); tail = XCDR (tail))
        if (maxlen < ASIZE (XCAR (tail)))
          maxlen = ASIZE (XCAR (tail));
    }
  else
    {
      /* We have to create a single vector to sort it.  */
      vec = font_vconcat_entity_vectors (list);
      maxlen = ASIZE (vec);
    }

  data = SAFE_ALLOCA (maxlen * sizeof *data);
  best_score = 0xFFFFFFFF;
  best_entity = Qnil;

  for (tail = list; CONSP (tail); tail = XCDR (tail))
    {
      int font_driver_preference = 0;
      Lisp_Object current_font_driver;

      if (best_only)
        vec = XCAR (tail);
      len = ASIZE (vec);

      /* We are sure that the length of VEC > 0.  */
      current_font_driver = AREF (AREF (vec, 0), FONT_TYPE_INDEX);
      /* Score the elements.  */
      for (i = 0; i < len; i++)
        {
          data[i].entity = AREF (vec, i);
          data[i].score
            = ((best_only <= 0 || font_has_char (f, data[i].entity, best_only)
                > 0)
               ? font_score (data[i].entity, prefer_prop)
               : 0xFFFFFFFF);
          if (best_only && best_score > data[i].score)
            {
              best_score = data[i].score;
              best_entity = data[i].entity;
              if (best_score == 0)
                break;
            }
          if (! EQ (current_font_driver, AREF (AREF (vec, i), FONT_TYPE_INDEX)))
            {
              current_font_driver = AREF (AREF (vec, i), FONT_TYPE_INDEX);
              font_driver_preference++;
            }
          data[i].font_driver_preference = font_driver_preference;
        }

      /* Sort if necessary.  */
      if (! best_only)
        {
          qsort (data, len, sizeof *data, font_compare);
          for (i = 0; i < len; i++)
            ASET (vec, i, data[i].entity);
          break;
        }
      else
        vec = best_entity;
    }

  SAFE_FREE ();

  FONT_ADD_LOG ("sort-by", prefer, vec);
  return vec;
}

\f
/* API of Font Service Layer.  */

/* Reflect ORDER (see the variable font_sort_order in xfaces.c) to
   sort_shift_bits.  Finternal_set_font_selection_order calls this
   function with font_sort_order after setting up it.  */

void
font_update_sort_order (int *order)
{
  int i, shift_bits;

  for (i = 0, shift_bits = 23; i < 4; i++, shift_bits -= 7)
    {
      int xlfd_idx = order[i];

      if (xlfd_idx == XLFD_WEIGHT_INDEX)
        sort_shift_bits[FONT_WEIGHT_INDEX] = shift_bits;
      else if (xlfd_idx == XLFD_SLANT_INDEX)
        sort_shift_bits[FONT_SLANT_INDEX] = shift_bits;
      else if (xlfd_idx == XLFD_SWIDTH_INDEX)
        sort_shift_bits[FONT_WIDTH_INDEX] = shift_bits;
      else
        sort_shift_bits[FONT_SIZE_INDEX] = shift_bits;
    }
}

static bool
font_check_otf_features (Lisp_Object script, Lisp_Object langsys,
                         Lisp_Object features, Lisp_Object table)
{
  Lisp_Object val;
  bool negative;

  table = assq_no_quit (script, table);
  if (NILP (table))
    return 0;
  table = XCDR (table);
  if (! NILP (langsys))
    {
      table = assq_no_quit (langsys, table);
      if (NILP (table))
        return 0;
    }
  else
    {
      val = assq_no_quit (Qnil, table);
      if (NILP (val))
        table = XCAR (table);
      else
        table = val;
    }
  table = XCDR (table);
  for (negative = 0; CONSP (features); features = XCDR (features))
    {
      if (NILP (XCAR (features)))
        {
          negative = 1;
          continue;
        }
      if (NILP (Fmemq (XCAR (features), table)) != negative)
        return 0;
    }
  return 1;
}

/* Check if OTF_CAPABILITY satisfies SPEC (otf-spec).  */

static bool
font_check_otf (Lisp_Object spec, Lisp_Object otf_capability)
{
  Lisp_Object script, langsys = Qnil, gsub = Qnil, gpos = Qnil;

  script = XCAR (spec);
  spec = XCDR (spec);
  if (! NILP (spec))
    {
      langsys = XCAR (spec);
      spec = XCDR (spec);
      if (! NILP (spec))
        {
          gsub = XCAR (spec);
          spec = XCDR (spec);
          if (! NILP (spec))
            gpos = XCAR (spec);
        }
    }

  if (! NILP (gsub) && ! font_check_otf_features (script, langsys, gsub,
                                                  XCAR (otf_capability)))
    return 0;
  if (! NILP (gpos) && ! font_check_otf_features (script, langsys, gpos,
                                                  XCDR (otf_capability)))
    return 0;
  return 1;
}



/* Check if FONT (font-entity or font-object) matches with the font
   specification SPEC.  */

bool
font_match_p (Lisp_Object spec, Lisp_Object font)
{
  Lisp_Object prop[FONT_SPEC_MAX], *props;
  Lisp_Object extra, font_extra;
  int i;

  for (i = FONT_FOUNDRY_INDEX; i <= FONT_REGISTRY_INDEX; i++)
    if (! NILP (AREF (spec, i))
        && ! NILP (AREF (font, i))
        && ! EQ (AREF (spec, i), AREF (font, i)))
      return 0;
  props = XFONT_SPEC (spec)->props;
  if (FLOATP (props[FONT_SIZE_INDEX]))
    {
      for (i = FONT_FOUNDRY_INDEX; i < FONT_SIZE_INDEX; i++)
        prop[i] = AREF (spec, i);
      prop[FONT_SIZE_INDEX]
        = make_number (font_pixel_size (XFRAME (selected_frame), spec));
      props = prop;
    }

  if (font_score (font, props) > 0)
    return 0;
  extra = AREF (spec, FONT_EXTRA_INDEX);
  font_extra = AREF (font, FONT_EXTRA_INDEX);
  for (; CONSP (extra); extra = XCDR (extra))
    {
      Lisp_Object key = XCAR (XCAR (extra));
      Lisp_Object val = XCDR (XCAR (extra)), val2;

      if (EQ (key, QClang))
        {
          val2 = assq_no_quit (key, font_extra);
          if (NILP (val2))
            return 0;
          val2 = XCDR (val2);
          if (CONSP (val))
            {
              if (! CONSP (val2))
                return 0;
              while (CONSP (val))
                if (NILP (Fmemq (val, val2)))
                  return 0;
            }
          else
            if (CONSP (val2)
                ? NILP (Fmemq (val, XCDR (val2)))
                : ! EQ (val, val2))
              return 0;
        }
      else if (EQ (key, QCscript))
        {
          val2 = assq_no_quit (val, Vscript_representative_chars);
          if (CONSP (val2))
            {
              val2 = XCDR (val2);
              if (CONSP (val2))
                {
                  /* All characters in the list must be supported.  */
                  for (; CONSP (val2); val2 = XCDR (val2))
                    {
                      if (! CHARACTERP (XCAR (val2)))
                        continue;
                      if (font_encode_char (font, XFASTINT (XCAR (val2)))
                          == FONT_INVALID_CODE)
                        return 0;
                    }
                }
              else if (VECTORP (val2))
                {
                  /* At most one character in the vector must be supported.  */
                  for (i = 0; i < ASIZE (val2); i++)
                    {
                      if (! CHARACTERP (AREF (val2, i)))
                        continue;
                      if (font_encode_char (font, XFASTINT (AREF (val2, i)))
                          != FONT_INVALID_CODE)
                        break;
                    }
                  if (i == ASIZE (val2))
                    return 0;
                }
            }
        }
      else if (EQ (key, QCotf))
        {
          struct font *fontp;

          if (! FONT_OBJECT_P (font))
            return 0;
          fontp = XFONT_OBJECT (font);
          if (! fontp->driver->otf_capability)
            return 0;
          val2 = fontp->driver->otf_capability (fontp);
          if (NILP (val2) || ! font_check_otf (val, val2))
            return 0;
        }
    }

  return 1;
}
\f

/* Font cache

   Each font backend has the callback function get_cache, and it
   returns a cons cell of which cdr part can be freely used for
   caching fonts.  The cons cell may be shared by multiple frames
   and/or multiple font drivers.  So, we arrange the cdr part as this:

        ((DRIVER-TYPE NUM-FRAMES FONT-CACHE-DATA ...) ...)

   where DRIVER-TYPE is a symbol such as `x', `xft', etc., NUM-FRAMES
   is a number frames sharing this cache, and FONT-CACHE-DATA is a
   cons (FONT-SPEC . [FONT-ENTITY ...]).  */

static void font_clear_cache (struct frame *, Lisp_Object,
                              struct font_driver const *);

static void
font_prepare_cache (struct frame *f, struct font_driver const *driver)
{
  Lisp_Object cache, val;

  cache = driver->get_cache (f);
  val = XCDR (cache);
  while (CONSP (val) && ! EQ (XCAR (XCAR (val)), driver->type))
    val = XCDR (val);
  if (NILP (val))
    {
      val = list2 (driver->type, make_number (1));
      XSETCDR (cache, Fcons (val, XCDR (cache)));
    }
  else
    {
      val = XCDR (XCAR (val));
      XSETCAR (val, make_number (XINT (XCAR (val)) + 1));
    }
}


static void
font_finish_cache (struct frame *f, struct font_driver const *driver)
{
  Lisp_Object cache, val, tmp;


  cache = driver->get_cache (f);
  val = XCDR (cache);
  while (CONSP (val) && ! EQ (XCAR (XCAR (val)), driver->type))
    cache = val, val = XCDR (val);
  eassert (! NILP (val));
  tmp = XCDR (XCAR (val));
  XSETCAR (tmp, make_number (XINT (XCAR (tmp)) - 1));
  if (XINT (XCAR (tmp)) == 0)
    {
      font_clear_cache (f, XCAR (val), driver);
      XSETCDR (cache, XCDR (val));
    }
}


static Lisp_Object
font_get_cache (struct frame *f, struct font_driver const *driver)
{
  Lisp_Object val = driver->get_cache (f);
  Lisp_Object type = driver->type;

  eassert (CONSP (val));
  for (val = XCDR (val); ! EQ (XCAR (XCAR (val)), type); val = XCDR (val));
  eassert (CONSP (val));
  /* VAL = ((DRIVER-TYPE NUM-FRAMES FONT-CACHE-DATA ...) ...) */
  val = XCDR (XCAR (val));
  return val;
}


static void
font_clear_cache (struct frame *f, Lisp_Object cache,
                  struct font_driver const *driver)
{
  Lisp_Object tail, elt;
  Lisp_Object entity;
  ptrdiff_t i;

  /* CACHE = (DRIVER-TYPE NUM-FRAMES FONT-CACHE-DATA ...) */
  for (tail = XCDR (XCDR (cache)); CONSP (tail); tail = XCDR (tail))
    {
      elt = XCAR (tail);
      /* elt should have the form (FONT-SPEC . [FONT-ENTITY ...]) */
      if (CONSP (elt) && FONT_SPEC_P (XCAR (elt)))
        {
          elt = XCDR (elt);
          eassert (VECTORP (elt));
          for (i = 0; i < ASIZE (elt); i++)
            {
              entity = AREF (elt, i);

              if (FONT_ENTITY_P (entity)
                  && EQ (driver->type, AREF (entity, FONT_TYPE_INDEX)))
                {
                  Lisp_Object objlist = AREF (entity, FONT_OBJLIST_INDEX);

                  for (; CONSP (objlist); objlist = XCDR (objlist))
                    {
                      Lisp_Object val = XCAR (objlist);
                      struct font *font = XFONT_OBJECT (val);

                      if (! NILP (AREF (val, FONT_TYPE_INDEX)))
                        {
                          eassert (font && driver == font->driver);
                          driver->close (font);
                        }
                    }
                  if (driver->free_entity)
                    driver->free_entity (entity);
                }
            }
        }
    }
  XSETCDR (cache, Qnil);
}
\f

static Lisp_Object scratch_font_spec, scratch_font_prefer;

/* Check each font-entity in VEC, and return a list of font-entities
   that satisfy these conditions:
     (1) matches with SPEC and SIZE if SPEC is not nil, and
     (2) doesn't match with any regexps in Vface_ignored_fonts (if non-nil).
*/

static Lisp_Object
font_delete_unmatched (Lisp_Object vec, Lisp_Object spec, int size)
{
  Lisp_Object entity, val;
  enum font_property_index prop;
  ptrdiff_t i;

  for (val = Qnil, i = ASIZE (vec) - 1; i >= 0; i--)
    {
      entity = AREF (vec, i);
      if (! NILP (Vface_ignored_fonts))
        {
          char name[256];
          ptrdiff_t namelen;
          Lisp_Object tail, regexp;

          namelen = font_unparse_xlfd (entity, 0, name, 256);
          if (namelen >= 0)
            {
              for (tail = Vface_ignored_fonts; CONSP (tail); tail = XCDR (tail))
                {
                  regexp = XCAR (tail);
                  if (STRINGP (regexp)
                      && fast_c_string_match_ignore_case (regexp, name,
                                                          namelen) >= 0)
                    break;
                }
              if (CONSP (tail))
                continue;
            }
        }
      if (NILP (spec))
        {
          val = Fcons (entity, val);
          continue;
        }
      for (prop = FONT_WEIGHT_INDEX; prop < FONT_SIZE_INDEX; prop++)
        if (INTEGERP (AREF (spec, prop))
            && ((XINT (AREF (spec, prop)) >> 8)
                != (XINT (AREF (entity, prop)) >> 8)))
          prop = FONT_SPEC_MAX;
      if (prop < FONT_SPEC_MAX
          && size
          && XINT (AREF (entity, FONT_SIZE_INDEX)) > 0)
        {
          int diff = XINT (AREF (entity, FONT_SIZE_INDEX)) - size;

          if (eabs (diff) > FONT_PIXEL_SIZE_QUANTUM)
            prop = FONT_SPEC_MAX;
        }
      if (prop < FONT_SPEC_MAX
          && INTEGERP (AREF (spec, FONT_DPI_INDEX))
          && INTEGERP (AREF (entity, FONT_DPI_INDEX))
          && XINT (AREF (entity, FONT_DPI_INDEX)) != 0
          && ! EQ (AREF (spec, FONT_DPI_INDEX), AREF (entity, FONT_DPI_INDEX)))
        prop = FONT_SPEC_MAX;
      if (prop < FONT_SPEC_MAX
          && INTEGERP (AREF (spec, FONT_AVGWIDTH_INDEX))
          && INTEGERP (AREF (entity, FONT_AVGWIDTH_INDEX))
          && XINT (AREF (entity, FONT_AVGWIDTH_INDEX)) != 0
          && ! EQ (AREF (spec, FONT_AVGWIDTH_INDEX),
                   AREF (entity, FONT_AVGWIDTH_INDEX)))
        prop = FONT_SPEC_MAX;
      if (prop < FONT_SPEC_MAX)
        val = Fcons (entity, val);
    }
  return (Fvconcat (1, &val));
}


/* Return a list of vectors of font-entities matching with SPEC on
   FRAME.  Each elements in the list is a vector of entities from the
   same font-driver.  */

Lisp_Object
font_list_entities (struct frame *f, Lisp_Object spec)
{
  struct font_driver_list *driver_list = f->font_driver_list;
  Lisp_Object ftype, val;
  Lisp_Object list = Qnil;
  int size;
  bool need_filtering = 0;
  int i;

  eassert (FONT_SPEC_P (spec));

  if (INTEGERP (AREF (spec, FONT_SIZE_INDEX)))
    size = XINT (AREF (spec, FONT_SIZE_INDEX));
  else if (FLOATP (AREF (spec, FONT_SIZE_INDEX)))
    size = font_pixel_size (f, spec);
  else
    size = 0;

  ftype = AREF (spec, FONT_TYPE_INDEX);
  for (i = FONT_FOUNDRY_INDEX; i <= FONT_REGISTRY_INDEX; i++)
    ASET (scratch_font_spec, i, AREF (spec, i));
  for (i = FONT_WEIGHT_INDEX; i < FONT_EXTRA_INDEX; i++)
    if (i != FONT_SPACING_INDEX)
      {
        ASET (scratch_font_spec, i, Qnil);
        if (! NILP (AREF (spec, i)))
          need_filtering = 1;
      }
  ASET (scratch_font_spec, FONT_SPACING_INDEX, AREF (spec, FONT_SPACING_INDEX));
  ASET (scratch_font_spec, FONT_EXTRA_INDEX, AREF (spec, FONT_EXTRA_INDEX));

  for (; driver_list; driver_list = driver_list->next)
    if (driver_list->on
        && (NILP (ftype) || EQ (driver_list->driver->type, ftype)))
      {
        Lisp_Object cache = font_get_cache (f, driver_list->driver);

        ASET (scratch_font_spec, FONT_TYPE_INDEX, driver_list->driver->type);
        val = assoc_no_quit (scratch_font_spec, XCDR (cache));
        if (CONSP (val))
          val = XCDR (val);
        else
          {
            Lisp_Object copy;

            val = driver_list->driver->list (f, scratch_font_spec);
            /* We put zero_vector in the font-cache to indicate that
               no fonts matching SPEC were found on the system.
               Failure to have this indication in the font cache can
               cause severe performance degradation in some rare
               cases, see bug#21028.  */
            if (NILP (val))
              val = zero_vector;
            else
              val = Fvconcat (1, &val);
            copy = copy_font_spec (scratch_font_spec);
            ASET (copy, FONT_TYPE_INDEX, driver_list->driver->type);
            XSETCDR (cache, Fcons (Fcons (copy, val), XCDR (cache)));
          }
        if (ASIZE (val) > 0
            && (need_filtering
                || ! NILP (Vface_ignored_fonts)))
          val = font_delete_unmatched (val, need_filtering ? spec : Qnil, size);
        if (ASIZE (val) > 0)
          list = Fcons (val, list);
      }

  list = Fnreverse (list);
  FONT_ADD_LOG ("list", spec, list);
  return list;
}


/* Return a font entity matching with SPEC on FRAME.  ATTRS, if non
   nil, is an array of face's attributes, which specifies preferred
   font-related attributes.  */

static Lisp_Object
font_matching_entity (struct frame *f, Lisp_Object *attrs, Lisp_Object spec)
{
  struct font_driver_list *driver_list = f->font_driver_list;
  Lisp_Object ftype, size, entity;
  Lisp_Object work = copy_font_spec (spec);

  ftype = AREF (spec, FONT_TYPE_INDEX);
  size = AREF (spec, FONT_SIZE_INDEX);

  if (FLOATP (size))
    ASET (work, FONT_SIZE_INDEX, make_number (font_pixel_size (f, spec)));
  FONT_SET_STYLE (work, FONT_WEIGHT_INDEX, attrs[LFACE_WEIGHT_INDEX]);
  FONT_SET_STYLE (work, FONT_SLANT_INDEX, attrs[LFACE_SLANT_INDEX]);
  FONT_SET_STYLE (work, FONT_WIDTH_INDEX, attrs[LFACE_SWIDTH_INDEX]);

  entity = Qnil;
  for (; driver_list; driver_list = driver_list->next)
    if (driver_list->on
        && (NILP (ftype) || EQ (driver_list->driver->type, ftype)))
      {
        Lisp_Object cache = font_get_cache (f, driver_list->driver);

        ASET (work, FONT_TYPE_INDEX, driver_list->driver->type);
        entity = assoc_no_quit (work, XCDR (cache));
        if (CONSP (entity))
          entity = AREF (XCDR (entity), 0);
        else
          {
            entity = driver_list->driver->match (f, work);
            if (!NILP (entity))
              {
                Lisp_Object copy = copy_font_spec (work);
                Lisp_Object match = Fvector (1, &entity);

                ASET (copy, FONT_TYPE_INDEX, driver_list->driver->type);
                XSETCDR (cache, Fcons (Fcons (copy, match), XCDR (cache)));
              }
          }
        if (! NILP (entity))
          break;
      }
  FONT_ADD_LOG ("match", work, entity);
  return entity;
}


/* Open a font of ENTITY and PIXEL_SIZE on frame F, and return the
   opened font object.  */

static Lisp_Object
font_open_entity (struct frame *f, Lisp_Object entity, int pixel_size)
{
  struct font_driver_list *driver_list;
  Lisp_Object objlist, size, val, font_object;
  struct font *font;
  int height, psize;

  eassert (FONT_ENTITY_P (entity));
  size = AREF (entity, FONT_SIZE_INDEX);
  if (XINT (size) != 0)
    pixel_size = XINT (size);

  val = AREF (entity, FONT_TYPE_INDEX);
  for (driver_list = f->font_driver_list;
       driver_list && ! EQ (driver_list->driver->type, val);
       driver_list = driver_list->next);
  if (! driver_list)
    return Qnil;

  for (objlist = AREF (entity, FONT_OBJLIST_INDEX); CONSP (objlist);
       objlist = XCDR (objlist))
    {
      Lisp_Object fn = XCAR (objlist);
      if (! NILP (AREF (fn, FONT_TYPE_INDEX))
          && XFONT_OBJECT (fn)->pixel_size == pixel_size)
        {
          if (driver_list->driver->cached_font_ok == NULL
              || driver_list->driver->cached_font_ok (f, fn, entity))
            return fn;
        }
    }

  /* We always open a font of manageable size; i.e non-zero average
     width and height.  */
  for (psize = pixel_size; ; psize++)
    {
      font_object = driver_list->driver->open (f, entity, psize);
      if (NILP (font_object))
        return Qnil;
      font = XFONT_OBJECT (font_object);
      if (font->average_width > 0 && font->height > 0)
        break;
    }
  ASET (font_object, FONT_SIZE_INDEX, make_number (pixel_size));
  FONT_ADD_LOG ("open", entity, font_object);
  ASET (entity, FONT_OBJLIST_INDEX,
        Fcons (font_object, AREF (entity, FONT_OBJLIST_INDEX)));

  font = XFONT_OBJECT (font_object);
#ifdef HAVE_WINDOW_SYSTEM
  int min_width = (font->min_width ? font->min_width
                   : font->average_width ? font->average_width
                   : font->space_width ? font->space_width
                   : 1);
#endif

  int font_ascent, font_descent;
  get_font_ascent_descent (font, &font_ascent, &font_descent);
  height = font_ascent + font_descent;
  if (height <= 0)
    height = 1;
#ifdef HAVE_WINDOW_SYSTEM
  FRAME_DISPLAY_INFO (f)->n_fonts++;
  if (FRAME_DISPLAY_INFO (f)->n_fonts == 1)
    {
      FRAME_SMALLEST_CHAR_WIDTH (f) = min_width;
      FRAME_SMALLEST_FONT_HEIGHT (f) = height;
      f->fonts_changed = 1;
    }
  else
    {
      if (FRAME_SMALLEST_CHAR_WIDTH (f) > min_width)
        FRAME_SMALLEST_CHAR_WIDTH (f) = min_width, f->fonts_changed = 1;
      if (FRAME_SMALLEST_FONT_HEIGHT (f) > height)
        FRAME_SMALLEST_FONT_HEIGHT (f) = height, f->fonts_changed = 1;
    }
#endif

  return font_object;
}


/* Close FONT_OBJECT that is opened on frame F.  */

static void
font_close_object (struct frame *f, Lisp_Object font_object)
{
  struct font *font = XFONT_OBJECT (font_object);

  if (NILP (AREF (font_object, FONT_TYPE_INDEX)))
    /* Already closed.  */
    return;
  FONT_ADD_LOG ("close", font_object, Qnil);
  font->driver->close (font);
#ifdef HAVE_WINDOW_SYSTEM
  eassert (FRAME_DISPLAY_INFO (f)->n_fonts);
  FRAME_DISPLAY_INFO (f)->n_fonts--;
#endif
}


/* Return 1 if FONT on F has a glyph for character C, 0 if not, -1 if
   FONT is a font-entity and it must be opened to check.  */

int
font_has_char (struct frame *f, Lisp_Object font, int c)
{
  struct font *fontp;

  if (FONT_ENTITY_P (font))
    {
      Lisp_Object type = AREF (font, FONT_TYPE_INDEX);
      struct font_driver_list *driver_list;

      for (driver_list = f->font_driver_list;
           driver_list && ! EQ (driver_list->driver->type, type);
           driver_list = driver_list->next);
      if (! driver_list)
        return 0;
      if (! driver_list->driver->has_char)
        return -1;
      return driver_list->driver->has_char (font, c);
    }

  eassert (FONT_OBJECT_P (font));
  fontp = XFONT_OBJECT (font);
  if (fontp->driver->has_char)
    {
      int result = fontp->driver->has_char (font, c);

      if (result >= 0)
        return result;
    }
  return (fontp->driver->encode_char (fontp, c) != FONT_INVALID_CODE);
}


/* Return the glyph ID of FONT_OBJECT for character C.  */

static unsigned
font_encode_char (Lisp_Object font_object, int c)
{
  struct font *font;

  eassert (FONT_OBJECT_P (font_object));
  font = XFONT_OBJECT (font_object);
  return font->driver->encode_char (font, c);
}


/* Return the name of FONT_OBJECT.  */

Lisp_Object
font_get_name (Lisp_Object font_object)
{
  eassert (FONT_OBJECT_P (font_object));
  return AREF (font_object, FONT_NAME_INDEX);
}


/* Create a new font spec from FONT_NAME, and return it.  If FONT_NAME
   could not be parsed by font_parse_name, return Qnil.  */

Lisp_Object
font_spec_from_name (Lisp_Object font_name)
{
  Lisp_Object spec = Ffont_spec (0, NULL);

  CHECK_STRING (font_name);
  if (font_parse_name (SSDATA (font_name), SBYTES (font_name), spec) == -1)
    return Qnil;
  font_put_extra (spec, QCname, font_name);
  font_put_extra (spec, QCuser_spec, font_name);
  return spec;
}


void
font_clear_prop (Lisp_Object *attrs, enum font_property_index prop)
{
  Lisp_Object font = attrs[LFACE_FONT_INDEX];

  if (! FONTP (font))
    return;

  if (! NILP (Ffont_get (font, QCname)))
    {
      font = copy_font_spec (font);
      font_put_extra (font, QCname, Qnil);
    }

  if (NILP (AREF (font, prop))
      && prop != FONT_FAMILY_INDEX
      && prop != FONT_FOUNDRY_INDEX
      && prop != FONT_WIDTH_INDEX
      && prop != FONT_SIZE_INDEX)
    return;
  if (EQ (font, attrs[LFACE_FONT_INDEX]))
    font = copy_font_spec (font);
  ASET (font, prop, Qnil);
  if (prop == FONT_FAMILY_INDEX || prop == FONT_FOUNDRY_INDEX)
    {
      if (prop == FONT_FAMILY_INDEX)
        {
          ASET (font, FONT_FOUNDRY_INDEX, Qnil);
          /* If we are setting the font family, we must also clear
             FONT_WIDTH_INDEX to avoid rejecting families that lack
             support for some widths.  */
          ASET (font, FONT_WIDTH_INDEX, Qnil);
        }
      ASET (font, FONT_ADSTYLE_INDEX, Qnil);
      ASET (font, FONT_REGISTRY_INDEX, Qnil);
      ASET (font, FONT_SIZE_INDEX, Qnil);
      ASET (font, FONT_DPI_INDEX, Qnil);
      ASET (font, FONT_SPACING_INDEX, Qnil);
      ASET (font, FONT_AVGWIDTH_INDEX, Qnil);
    }
  else if (prop == FONT_SIZE_INDEX)
    {
      ASET (font, FONT_DPI_INDEX, Qnil);
      ASET (font, FONT_SPACING_INDEX, Qnil);
      ASET (font, FONT_AVGWIDTH_INDEX, Qnil);
    }
  else if (prop == FONT_WIDTH_INDEX)
    ASET (font, FONT_AVGWIDTH_INDEX, Qnil);
  attrs[LFACE_FONT_INDEX] = font;
}

/* Select a font from ENTITIES (list of font-entity vectors) that
   supports C and is the best match for ATTRS and PIXEL_SIZE.  */

static Lisp_Object
font_select_entity (struct frame *f, Lisp_Object entities,
                    Lisp_Object *attrs, int pixel_size, int c)
{
  Lisp_Object font_entity;
  Lisp_Object prefer;
  int i;

  if (NILP (XCDR (entities))
      && ASIZE (XCAR (entities)) == 1)
    {
      font_entity = AREF (XCAR (entities), 0);
      if (c < 0 || font_has_char (f, font_entity, c) > 0)
        return font_entity;
      return Qnil;
    }

  /* Sort fonts by properties specified in ATTRS.  */
  prefer = scratch_font_prefer;

  for (i = FONT_WEIGHT_INDEX; i <= FONT_SIZE_INDEX; i++)
    ASET (prefer, i, Qnil);
  if (FONTP (attrs[LFACE_FONT_INDEX]))
    {
      Lisp_Object face_font = attrs[LFACE_FONT_INDEX];

      for (i = FONT_WEIGHT_INDEX; i <= FONT_SIZE_INDEX; i++)
        ASET (prefer, i, AREF (face_font, i));
    }
  if (NILP (AREF (prefer, FONT_WEIGHT_INDEX)))
    FONT_SET_STYLE (prefer, FONT_WEIGHT_INDEX, attrs[LFACE_WEIGHT_INDEX]);
  if (NILP (AREF (prefer, FONT_SLANT_INDEX)))
    FONT_SET_STYLE (prefer, FONT_SLANT_INDEX, attrs[LFACE_SLANT_INDEX]);
  if (NILP (AREF (prefer, FONT_WIDTH_INDEX)))
    FONT_SET_STYLE (prefer, FONT_WIDTH_INDEX, attrs[LFACE_SWIDTH_INDEX]);
  ASET (prefer, FONT_SIZE_INDEX, make_number (pixel_size));

  return font_sort_entities (entities, prefer, f, c);
}

/* Return a font-entity that satisfies SPEC and is the best match for
   face's font related attributes in ATTRS.  C, if not negative, is a
   character that the entity must support.  */

Lisp_Object
font_find_for_lface (struct frame *f, Lisp_Object *attrs, Lisp_Object spec, int c)
{
  Lisp_Object work;
  Lisp_Object entities, val;
  Lisp_Object foundry[3], *family, registry[3], adstyle[3];
  int pixel_size;
  int i, j, k, l;
  USE_SAFE_ALLOCA;

  registry[0] = AREF (spec, FONT_REGISTRY_INDEX);
  if (NILP (registry[0]))
    {
      registry[0] = DEFAULT_ENCODING;
      registry[1] = Qascii_0;
      registry[2] = zero_vector;
    }
  else
    registry[1] = zero_vector;

  if (c >= 0 && ! NILP (AREF (spec, FONT_REGISTRY_INDEX)))
    {
      struct charset *encoding, *repertory;

      if (font_registry_charsets (AREF (spec, FONT_REGISTRY_INDEX),
                                  &encoding, &repertory) < 0)
        return Qnil;
      if (repertory
          && ENCODE_CHAR (repertory, c) == CHARSET_INVALID_CODE (repertory))
        return Qnil;
      else if (c > encoding->max_char)
        return Qnil;
    }

  work = copy_font_spec (spec);
  ASET (work, FONT_TYPE_INDEX, AREF (spec, FONT_TYPE_INDEX));
  pixel_size = font_pixel_size (f, spec);
  if (pixel_size == 0 && INTEGERP (attrs[LFACE_HEIGHT_INDEX]))
    {
      double pt = XINT (attrs[LFACE_HEIGHT_INDEX]);

      pixel_size = POINT_TO_PIXEL (pt / 10, FRAME_RES_Y (f));
      if (pixel_size < 1)
        pixel_size = 1;
    }
  ASET (work, FONT_SIZE_INDEX, Qnil);
  foundry[0] = AREF (work, FONT_FOUNDRY_INDEX);
  if (! NILP (foundry[0]))
    foundry[1] = zero_vector;
  else if (STRINGP (attrs[LFACE_FOUNDRY_INDEX]))
    {
      val = attrs[LFACE_FOUNDRY_INDEX];
      foundry[0] = font_intern_prop (SSDATA (val), SBYTES (val), 1);
      foundry[1] = Qnil;
      foundry[2] = zero_vector;
    }
  else
    foundry[0] = Qnil, foundry[1] = zero_vector;

  adstyle[0] = AREF (work, FONT_ADSTYLE_INDEX);
  if (! NILP (adstyle[0]))
    adstyle[1] = zero_vector;
  else if (FONTP (attrs[LFACE_FONT_INDEX]))
    {
      Lisp_Object face_font = attrs[LFACE_FONT_INDEX];

      if (! NILP (AREF (face_font, FONT_ADSTYLE_INDEX)))
        {
          adstyle[0] = AREF (face_font, FONT_ADSTYLE_INDEX);
          adstyle[1] = Qnil;
          adstyle[2] = zero_vector;
        }
      else
        adstyle[0] = Qnil, adstyle[1] = zero_vector;
    }
  else
    adstyle[0] = Qnil, adstyle[1] = zero_vector;


  val = AREF (work, FONT_FAMILY_INDEX);
  if (NILP (val) && STRINGP (attrs[LFACE_FAMILY_INDEX]))
    {
      val = attrs[LFACE_FAMILY_INDEX];
      val = font_intern_prop (SSDATA (val), SBYTES (val), 1);
    }
  Lisp_Object familybuf[3];
  if (NILP (val))
    {
      family = familybuf;
      family[0] = Qnil;
      family[1] = zero_vector;  /* terminator.  */
    }
  else
    {
      Lisp_Object alters
        = Fassoc_string (val, Vface_alternative_font_family_alist, Qt);

      if (! NILP (alters))
        {
          EMACS_INT alterslen = XFASTINT (Flength (alters));
          SAFE_ALLOCA_LISP (family, alterslen + 2);
          for (i = 0; CONSP (alters); i++, alters = XCDR (alters))
            family[i] = XCAR (alters);
          if (NILP (AREF (spec, FONT_FAMILY_INDEX)))
            family[i++] = Qnil;
          family[i] = zero_vector;
        }
      else
        {
          family = familybuf;
          i = 0;
          family[i++] = val;
          if (NILP (AREF (spec, FONT_FAMILY_INDEX)))
            family[i++] = Qnil;
          family[i] = zero_vector;
        }
    }

  for (i = 0; SYMBOLP (family[i]); i++)
    {
      ASET (work, FONT_FAMILY_INDEX, family[i]);
      for (j = 0; SYMBOLP (foundry[j]); j++)
        {
          ASET (work, FONT_FOUNDRY_INDEX, foundry[j]);
          for (k = 0; SYMBOLP (registry[k]); k++)
            {
              ASET (work, FONT_REGISTRY_INDEX, registry[k]);
              for (l = 0; SYMBOLP (adstyle[l]); l++)
                {
                  ASET (work, FONT_ADSTYLE_INDEX, adstyle[l]);
                  entities = font_list_entities (f, work);
                  if (! NILP (entities))
                    {
                      val = font_select_entity (f, entities,
                                                attrs, pixel_size, c);
                      if (! NILP (val))
                        {
                          SAFE_FREE ();
                          return val;
                        }
                    }
                }
            }
        }
    }

  SAFE_FREE ();
  return Qnil;
}


Lisp_Object
font_open_for_lface (struct frame *f, Lisp_Object entity, Lisp_Object *attrs, Lisp_Object spec)
{
  int size;

  if (INTEGERP (AREF (entity, FONT_SIZE_INDEX))
      && XINT (AREF (entity, FONT_SIZE_INDEX)) > 0)
    size = XINT (AREF (entity, FONT_SIZE_INDEX));
  else
    {
      if (FONT_SPEC_P (spec) && ! NILP (AREF (spec, FONT_SIZE_INDEX)))
        size = font_pixel_size (f, spec);
      else
        {
          double pt;
          if (INTEGERP (attrs[LFACE_HEIGHT_INDEX]))
            pt = XINT (attrs[LFACE_HEIGHT_INDEX]);
          else
            {
              struct face *def = FACE_FROM_ID (f, DEFAULT_FACE_ID);
              Lisp_Object height = def->lface[LFACE_HEIGHT_INDEX];
              eassert (INTEGERP (height));
              pt = XINT (height);
            }

          pt /= 10;
          size = POINT_TO_PIXEL (pt, FRAME_RES_Y (f));
#ifdef HAVE_NS
          if (size == 0)
            {
              Lisp_Object ffsize = get_frame_param (f, Qfontsize);
              size = (NUMBERP (ffsize)
                      ? POINT_TO_PIXEL (XINT (ffsize), FRAME_RES_Y (f)) : 0);
            }
#endif
        }
      size *= font_rescale_ratio (entity);
    }

  return font_open_entity (f, entity, size);
}


/* Find a font that satisfies SPEC and is the best match for
   face's attributes in ATTRS on FRAME, and return the opened
   font-object.  */

Lisp_Object
font_load_for_lface (struct frame *f, Lisp_Object *attrs, Lisp_Object spec)
{
  Lisp_Object entity, name;

  entity = font_find_for_lface (f, attrs, spec, -1);
  if (NILP (entity))
    {
      /* No font is listed for SPEC, but each font-backend may have
         different criteria about "font matching".  So, try it.  */
      entity = font_matching_entity (f, attrs, spec);
      /* Perhaps the user asked for a font "Foobar-123", and we
         interpreted "-123" as the size, whereas it really is part of
         the name.  So we reset the size to nil and the family name to
         the entire "Foobar-123" thing, and try again with that.  */
      if (NILP (entity))
        {
          name = Ffont_get (spec, QCuser_spec);
          if (STRINGP (name))
            {
              char *p = SSDATA (name), *q = strrchr (p, '-');

              if (q != NULL && c_isdigit (q[1]))
                {
                  char *tail;
                  double font_size = strtod (q + 1, &tail);

                  if (font_size > 0 && tail != q + 1)
                    {
                      Lisp_Object lsize = Ffont_get (spec, QCsize);

                      if ((FLOATP (lsize) && XFLOAT_DATA (lsize) == font_size)
                          || (INTEGERP (lsize) && XINT (lsize) == font_size))
                        {
                          ASET (spec, FONT_FAMILY_INDEX,
                                font_intern_prop (p, tail - p, 1));
                          ASET (spec, FONT_SIZE_INDEX, Qnil);
                          entity = font_matching_entity (f, attrs, spec);
                        }
                    }
                }
            }
        }
      if (NILP (entity))
        return Qnil;
    }
  /* Don't lose the original name that was put in initially.  We need
     it to re-apply the font when font parameters (like hinting or dpi) have
     changed.  */
  entity = font_open_for_lface (f, entity, attrs, spec);
  if (!NILP (entity))
    {
      name = Ffont_get (spec, QCuser_spec);
      if (STRINGP (name)) font_put_extra (entity, QCuser_spec, name);
    }
  return entity;
}


/* Make FACE on frame F ready to use the font opened for FACE.  */

void
font_prepare_for_face (struct frame *f, struct face *face)
{
  if (face->font->driver->prepare_face)
    face->font->driver->prepare_face (f, face);
}


/* Make FACE on frame F stop using the font opened for FACE.  */

void
font_done_for_face (struct frame *f, struct face *face)
{
  if (face->font->driver->done_face)
    face->font->driver->done_face (f, face);
}


/* Open a font that is a match for font-spec SPEC on frame F.  If no proper
   font is found, return Qnil.  */

Lisp_Object
font_open_by_spec (struct frame *f, Lisp_Object spec)
{
  Lisp_Object attrs[LFACE_VECTOR_SIZE];

  /* We set up the default font-related attributes of a face to prefer
     a moderate font.  */
  attrs[LFACE_FAMILY_INDEX] = attrs[LFACE_FOUNDRY_INDEX] = Qnil;
  attrs[LFACE_SWIDTH_INDEX] = attrs[LFACE_WEIGHT_INDEX]
    = attrs[LFACE_SLANT_INDEX] = Qnormal;
#ifndef HAVE_NS
  attrs[LFACE_HEIGHT_INDEX] = make_number (120);
#else
  attrs[LFACE_HEIGHT_INDEX] = make_number (0);
#endif
  attrs[LFACE_FONT_INDEX] = Qnil;

  return font_load_for_lface (f, attrs, spec);
}


/* Open a font that matches NAME on frame F.  If no proper font is
   found, return Qnil.  */

Lisp_Object
font_open_by_name (struct frame *f, Lisp_Object name)
{
  Lisp_Object spec = CALLN (Ffont_spec, QCname, name);
  Lisp_Object ret = font_open_by_spec (f, spec);
  /* Do not lose name originally put in.  */
  if (!NILP (ret))
    font_put_extra (ret, QCuser_spec, name);

  return ret;
}


/* Register font-driver DRIVER.  This function is used in two ways.

   The first is with frame F non-NULL.  In this case, make DRIVER
   available (but not yet activated) on F.  All frame creators
   (e.g. Fx_create_frame) must call this function at least once with
   an available font-driver.

   The second is with frame F NULL.  In this case, DRIVER is globally
   registered in the variable `font_driver_list'.  All font-driver
   implementations must call this function in its syms_of_XXXX
   (e.g. syms_of_xfont).  */

void
register_font_driver (struct font_driver const *driver, struct frame *f)
{
  struct font_driver_list *root = f ? f->font_driver_list : font_driver_list;
  struct font_driver_list *prev, *list;

#ifdef HAVE_WINDOW_SYSTEM
  if (f && ! driver->draw)
    error ("Unusable font driver for a frame: %s",
           SDATA (SYMBOL_NAME (driver->type)));
#endif /* HAVE_WINDOW_SYSTEM */

  for (prev = NULL, list = root; list; prev = list, list = list->next)
    if (EQ (list->driver->type, driver->type))
      error ("Duplicated font driver: %s", SDATA (SYMBOL_NAME (driver->type)));

  list = xmalloc (sizeof *list);
  list->on = 0;
  list->driver = driver;
  list->next = NULL;
  if (prev)
    prev->next = list;
  else if (f)
    f->font_driver_list = list;
  else
    font_driver_list = list;
  if (! f)
    num_font_drivers++;
}

void
free_font_driver_list (struct frame *f)
{
  struct font_driver_list *list, *next;

  for (list = f->font_driver_list; list; list = next)
    {
      next = list->next;
      xfree (list);
    }
  f->font_driver_list = NULL;
}


/* Make the frame F use font backends listed in NEW_DRIVERS (list of
   symbols, e.g. xft, x).  If NEW_DRIVERS is t, make F use all
   available font drivers.  If NEW_DRIVERS is nil, finalize all drivers.

   A caller must free all realized faces if any in advance.  The
   return value is a list of font backends actually made used on
   F.  */

Lisp_Object
font_update_drivers (struct frame *f, Lisp_Object new_drivers)
{
  Lisp_Object active_drivers = Qnil;
  struct font_driver_list *list;

  /* At first, turn off non-requested drivers, and turn on requested
     drivers.  */
  for (list = f->font_driver_list; list; list = list->next)
    {
      struct font_driver const *driver = list->driver;
      if ((EQ (new_drivers, Qt) || ! NILP (Fmemq (driver->type, new_drivers)))
          != list->on)
        {
          if (list->on)
            {
              if (driver->end_for_frame)
                driver->end_for_frame (f);
              font_finish_cache (f, driver);
              list->on = 0;
            }
          else
            {
              if (! driver->start_for_frame
                  || driver->start_for_frame (f) == 0)
                {
                  font_prepare_cache (f, driver);
                  list->on = 1;
                }
            }
        }
    }

  if (NILP (new_drivers))
    return Qnil;

  if (! EQ (new_drivers, Qt))
    {
      /* Re-order the driver list according to new_drivers.  */
      struct font_driver_list **list_table, **next;
      Lisp_Object tail;
      int i;
      USE_SAFE_ALLOCA;

      SAFE_NALLOCA (list_table, 1, num_font_drivers + 1);
      for (i = 0, tail = new_drivers; ! NILP (tail); tail = XCDR (tail))
        {
          for (list = f->font_driver_list; list; list = list->next)
            if (list->on && EQ (list->driver->type, XCAR (tail)))
              break;
          if (list)
            list_table[i++] = list;
        }
      for (list = f->font_driver_list; list; list = list->next)
        if (! list->on)
          list_table[i++] = list;
      list_table[i] = NULL;

      next = &f->font_driver_list;
      for (i = 0; list_table[i]; i++)
        {
          *next = list_table[i];
          next = &(*next)->next;
        }
      *next = NULL;
      SAFE_FREE ();

      if (! f->font_driver_list->on)
        { /* None of the drivers is enabled: enable them all.
             Happens if you set the list of drivers to (xft x) in your .emacs
             and then use it under w32 or ns.  */
          for (list = f->font_driver_list; list; list = list->next)
            {
              struct font_driver const *driver = list->driver;
              eassert (! list->on);
              if (! driver->start_for_frame
                  || driver->start_for_frame (f) == 0)
                {
                  font_prepare_cache (f, driver);
                  list->on = 1;
                }
            }
        }
    }

  for (list = f->font_driver_list; list; list = list->next)
    if (list->on)
      active_drivers = nconc2 (active_drivers, list1 (list->driver->type));
  return active_drivers;
}

#if defined (HAVE_XFT) || defined (HAVE_FREETYPE)

static void
fset_font_data (struct frame *f, Lisp_Object val)
{
  f->font_data = val;
}

void
font_put_frame_data (struct frame *f, Lisp_Object driver, void *data)
{
  Lisp_Object val = assq_no_quit (driver, f->font_data);

  if (!data)
    fset_font_data (f, Fdelq (val, f->font_data));
  else
    {
      if (NILP (val))
        fset_font_data (f, Fcons (Fcons (driver, make_save_ptr (data)),
                                  f->font_data));
      else
        XSETCDR (val, make_save_ptr (data));
    }
}

void *
font_get_frame_data (struct frame *f, Lisp_Object driver)
{
  Lisp_Object val = assq_no_quit (driver, f->font_data);

  return NILP (val) ? NULL : XSAVE_POINTER (XCDR (val), 0);
}

#endif /* HAVE_XFT || HAVE_FREETYPE */

/* Sets attributes on a font.  Any properties that appear in ALIST and
   BOOLEAN_PROPERTIES or NON_BOOLEAN_PROPERTIES are set on the font.
   BOOLEAN_PROPERTIES and NON_BOOLEAN_PROPERTIES are NULL-terminated
   arrays of strings.  This function is intended for use by the font
   drivers to implement their specific font_filter_properties.  */
void
font_filter_properties (Lisp_Object font,
                        Lisp_Object alist,
                        const char *const boolean_properties[],
                        const char *const non_boolean_properties[])
{
  Lisp_Object it;
  int i;

  /* Set boolean values to Qt or Qnil.  */
  for (i = 0; boolean_properties[i] != NULL; ++i)
    for (it = alist; ! NILP (it); it = XCDR (it))
      {
        Lisp_Object key = XCAR (XCAR (it));
        Lisp_Object val = XCDR (XCAR (it));
        char *keystr = SSDATA (SYMBOL_NAME (key));

        if (strcmp (boolean_properties[i], keystr) == 0)
          {
            const char *str = INTEGERP (val) ? (XINT (val) ? "true" : "false")
              : SYMBOLP (val) ? SSDATA (SYMBOL_NAME (val))
              : "true";

            if (strcmp ("false", str) == 0 || strcmp ("False", str) == 0
                || strcmp ("FALSE", str) == 0 || strcmp ("FcFalse", str) == 0
                || strcmp ("off", str) == 0 || strcmp ("OFF", str) == 0
                || strcmp ("Off", str) == 0)
              val = Qnil;
            else
              val = Qt;

            Ffont_put (font, key, val);
          }
      }

  for (i = 0; non_boolean_properties[i] != NULL; ++i)
    for (it = alist; ! NILP (it); it = XCDR (it))
      {
        Lisp_Object key = XCAR (XCAR (it));
        Lisp_Object val = XCDR (XCAR (it));
        char *keystr = SSDATA (SYMBOL_NAME (key));
        if (strcmp (non_boolean_properties[i], keystr) == 0)
          Ffont_put (font, key, val);
      }
}


/* Return the font used to draw character C by FACE at buffer position
   POS in window W.  If STRING is non-nil, it is a string containing C
   at index POS.  If C is negative, get C from the current buffer or
   STRING.  */

static Lisp_Object
font_at (int c, ptrdiff_t pos, struct face *face, struct window *w,
         Lisp_Object string)
{
  struct frame *f;
  bool multibyte;
  Lisp_Object font_object;

  multibyte = (NILP (string)
               ? ! NILP (BVAR (current_buffer, enable_multibyte_characters))
               : STRING_MULTIBYTE (string));
  if (c < 0)
    {
      if (NILP (string))
        {
          if (multibyte)
            {
              ptrdiff_t pos_byte = CHAR_TO_BYTE (pos);

              c = FETCH_CHAR (pos_byte);
            }
          else
            c = FETCH_BYTE (pos);
        }
      else
        {
          unsigned char *str;

          multibyte = STRING_MULTIBYTE (string);
          if (multibyte)
            {
              ptrdiff_t pos_byte = string_char_to_byte (string, pos);

              str = SDATA (string) + pos_byte;
              c = STRING_CHAR (str);
            }
          else
            c = SDATA (string)[pos];
        }
    }

  f = XFRAME (w->frame);
  if (! FRAME_WINDOW_P (f))
    return Qnil;
  if (! face)
    {
      int face_id;
      ptrdiff_t endptr;

      if (STRINGP (string))
        face_id = face_at_string_position (w, string, pos, 0, &endptr,
                                           DEFAULT_FACE_ID, false);
      else
        face_id = face_at_buffer_position (w, pos, &endptr,
                                           pos + 100, false, -1);
      face = FACE_FROM_ID (f, face_id);
    }
  if (multibyte)
    {
      int face_id = FACE_FOR_CHAR (f, face, c, pos, string);
      face = FACE_FROM_ID (f, face_id);
    }
  if (! face->font)
    return Qnil;

  XSETFONT (font_object, face->font);
  return font_object;
}


#ifdef HAVE_WINDOW_SYSTEM

/* Check how many characters after character/byte position POS/POS_BYTE
   (at most to *LIMIT) can be displayed by the same font in the window W.
   FACE, if non-NULL, is the face selected for the character at POS.
   If STRING is not nil, it is the string to check instead of the current
   buffer.  In that case, FACE must be not NULL.

   The return value is the font-object for the character at POS.
   *LIMIT is set to the position where that font can't be used.

   It is assured that the current buffer (or STRING) is multibyte.  */

Lisp_Object
font_range (ptrdiff_t pos, ptrdiff_t pos_byte, ptrdiff_t *limit,
            struct window *w, struct face *face, Lisp_Object string)
{
  ptrdiff_t ignore;
  int c;
  Lisp_Object font_object = Qnil;

  if (!face)
    {
      struct frame *f = XFRAME (w->frame);
      int face_id;

      if (NILP (string))
          face_id = face_at_buffer_position (w, pos, &ignore, *limit,
                                             false, -1);
      else
        {
          face_id =
            NILP (Vface_remapping_alist)
            ? DEFAULT_FACE_ID
            : lookup_basic_face (f, DEFAULT_FACE_ID);

          face_id = face_at_string_position (w, string, pos, 0, &ignore,
                                             face_id, false);
        }
      face = FACE_FROM_ID (f, face_id);
    }

  while (pos < *limit)
    {
      Lisp_Object category;

      if (NILP (string))
        FETCH_CHAR_ADVANCE_NO_CHECK (c, pos, pos_byte);
      else
        FETCH_STRING_CHAR_ADVANCE_NO_CHECK (c, string, pos, pos_byte);
      category = CHAR_TABLE_REF (Vunicode_category_table, c);
      if (INTEGERP (category)
          && (XINT (category) == UNICODE_CATEGORY_Cf
              || CHAR_VARIATION_SELECTOR_P (c)))
        continue;
      if (NILP (font_object))
        {
          font_object = font_for_char (face, c, pos - 1, string);
          if (NILP (font_object))
            return Qnil;
          continue;
        }
      if (font_encode_char (font_object, c) == FONT_INVALID_CODE)
        *limit = pos - 1;
    }
  return font_object;
}
#endif

\f
/* Lisp API.  */

DEFUN ("fontp", Ffontp, Sfontp, 1, 2, 0,
       doc: /* Return t if OBJECT is a font-spec, font-entity, or font-object.
Return nil otherwise.
Optional 2nd argument EXTRA-TYPE, if non-nil, specifies to check
which kind of font it is.  It must be one of `font-spec', `font-entity',
`font-object'.  */)
  (Lisp_Object object, Lisp_Object extra_type)
{
  if (NILP (extra_type))
    return (FONTP (object) ? Qt : Qnil);
  if (EQ (extra_type, Qfont_spec))
    return (FONT_SPEC_P (object) ? Qt : Qnil);
  if (EQ (extra_type, Qfont_entity))
    return (FONT_ENTITY_P (object) ? Qt : Qnil);
  if (EQ (extra_type, Qfont_object))
    return (FONT_OBJECT_P (object) ? Qt : Qnil);
  wrong_type_argument (intern ("font-extra-type"), extra_type);
}

DEFUN ("font-spec", Ffont_spec, Sfont_spec, 0, MANY, 0,
       doc: /* Return a newly created font-spec with arguments as properties.

ARGS must come in pairs KEY VALUE of font properties.  KEY must be a
valid font property name listed below:

`:family', `:weight', `:slant', `:width'

They are the same as face attributes of the same name.  See
`set-face-attribute'.

`:foundry'

VALUE must be a string or a symbol specifying the font foundry, e.g. `misc'.

`:adstyle'

VALUE must be a string or a symbol specifying the additional
typographic style information of a font, e.g. `sans'.

`:registry'

VALUE must be a string or a symbol specifying the charset registry and
encoding of a font, e.g. `iso8859-1'.

`:size'

VALUE must be a non-negative integer or a floating point number
specifying the font size.  It specifies the font size in pixels (if
VALUE is an integer), or in points (if VALUE is a float).

`:name'

VALUE must be a string of XLFD-style or fontconfig-style font name.

`:script'

VALUE must be a symbol representing a script that the font must
support.  It may be a symbol representing a subgroup of a script
listed in the variable `script-representative-chars'.

`:lang'

VALUE must be a symbol whose name is a two-letter ISO-639 language
name, e.g. `ja'.  The value is matched against the "Additional Style"
field of the XLFD spec of a font, if it's non-empty, on X, and
against the codepages supported by the font on w32.

`:otf'

VALUE must be a list (SCRIPT-TAG LANGSYS-TAG GSUB [ GPOS ]) to specify
required OpenType features.

  SCRIPT-TAG: OpenType script tag symbol (e.g. `deva').
  LANGSYS-TAG: OpenType language system tag symbol,
     or nil for the default language system.
  GSUB: List of OpenType GSUB feature tag symbols, or nil if none required.
  GPOS: List of OpenType GPOS feature tag symbols, or nil if none required.

GSUB and GPOS may contain nil elements.  In such a case, the font
must not have any of the remaining elements.

For instance, if the VALUE is `(thai nil nil (mark))', the font must
be an OpenType font whose GPOS table of `thai' script's default
language system must contain `mark' feature.

usage: (font-spec ARGS...)  */)
  (ptrdiff_t nargs, Lisp_Object *args)
{
  Lisp_Object spec = font_make_spec ();
  ptrdiff_t i;

  for (i = 0; i < nargs; i += 2)
    {
      Lisp_Object key = args[i], val;

      CHECK_SYMBOL (key);
      if (i + 1 >= nargs)
        error ("No value for key `%s'", SDATA (SYMBOL_NAME (key)));
      val = args[i + 1];

      if (EQ (key, QCname))
        {
          CHECK_STRING (val);
          if (font_parse_name (SSDATA (val), SBYTES (val), spec) < 0)
            error ("Invalid font name: %s", SSDATA (val));
          font_put_extra (spec, key, val);
        }
      else
        {
          int idx = get_font_prop_index (key);

          if (idx >= 0)
            {
              val = font_prop_validate (idx, Qnil, val);
              if (idx < FONT_EXTRA_INDEX)
                ASET (spec, idx, val);
              else
                font_put_extra (spec, key, val);
            }
          else
            font_put_extra (spec, key, font_prop_validate (0, key, val));
        }
    }
  return spec;
}

/* Return a copy of FONT as a font-spec.  For the sake of speed, this code
   relies on an internal stuff exposed from alloc.c and should be handled
   with care. */

Lisp_Object
copy_font_spec (Lisp_Object font)
{
  enum { font_spec_size = VECSIZE (struct font_spec) };
  Lisp_Object new_spec, tail, *pcdr;
  struct font_spec *spec;

  CHECK_FONT (font);

  /* Make an uninitialized font-spec object.  */
  spec = (struct font_spec *) allocate_vector (font_spec_size);
  XSETPVECTYPESIZE (spec, PVEC_FONT, FONT_SPEC_MAX,
                    font_spec_size - FONT_SPEC_MAX);

  spec->props[FONT_TYPE_INDEX] = spec->props[FONT_EXTRA_INDEX] = Qnil;

  /* Copy basic properties FONT_FOUNDRY_INDEX..FONT_AVGWIDTH_INDEX.  */
  memcpy (spec->props + 1, XVECTOR (font)->contents + 1,
          (FONT_EXTRA_INDEX - 1) * word_size);

  /* Copy an alist of extra information but discard :font-entity property.  */
  pcdr = spec->props + FONT_EXTRA_INDEX;
  for (tail = AREF (font, FONT_EXTRA_INDEX); CONSP (tail); tail = XCDR (tail))
    if (!EQ (XCAR (XCAR (tail)), QCfont_entity))
      {
        *pcdr = Fcons (Fcons (XCAR (XCAR (tail)), CDR (XCAR (tail))), Qnil);
        pcdr = xcdr_addr (*pcdr);
      }

  XSETFONT (new_spec, spec);
  return new_spec;
}

/* Merge font-specs FROM and TO, and return a new font-spec.
   Every specified property in FROM overrides the corresponding
   property in TO.  */
Lisp_Object
merge_font_spec (Lisp_Object from, Lisp_Object to)
{
  Lisp_Object extra, tail;
  int i;

  CHECK_FONT (from);
  CHECK_FONT (to);
  to = copy_font_spec (to);
  for (i = 0; i < FONT_EXTRA_INDEX; i++)
    ASET (to, i, AREF (from, i));
  extra = AREF (to, FONT_EXTRA_INDEX);
  for (tail = AREF (from, FONT_EXTRA_INDEX); CONSP (tail); tail = XCDR (tail))
    if (! EQ (XCAR (XCAR (tail)), Qfont_entity))
      {
        Lisp_Object slot = assq_no_quit (XCAR (XCAR (tail)), extra);

        if (! NILP (slot))
          XSETCDR (slot, XCDR (XCAR (tail)));
        else
          extra = Fcons (Fcons (XCAR (XCAR (tail)), XCDR (XCAR (tail))), extra);
      }
  ASET (to, FONT_EXTRA_INDEX, extra);
  return to;
}

DEFUN ("font-get", Ffont_get, Sfont_get, 2, 2, 0,
       doc: /* Return the value of FONT's property KEY.
FONT is a font-spec, a font-entity, or a font-object.
KEY is any symbol, but these are reserved for specific meanings:
  :family, :weight, :slant, :width, :foundry, :adstyle, :registry,
  :size, :name, :script, :otf
See the documentation of `font-spec' for their meanings.
In addition, if FONT is a font-entity or a font-object, values of
:script and :otf are different from those of a font-spec as below:

The value of :script may be a list of scripts that are supported by the font.

The value of :otf is a cons (GSUB . GPOS) where GSUB and GPOS are lists
representing the OpenType features supported by the font by this form:
  ((SCRIPT (LANGSYS FEATURE ...) ...) ...)
SCRIPT, LANGSYS, and FEATURE are all symbols representing OpenType
Layout tags.

In addition to the keys listed abobe, the following keys are reserved
for the specific meanings as below:

The value of :combining-capability is non-nil if the font-backend of
FONT supports rendering of combining characters for non-OTF fonts.  */)
  (Lisp_Object font, Lisp_Object key)
{
  int idx;
  Lisp_Object val;

  CHECK_FONT (font);
  CHECK_SYMBOL (key);

  idx = get_font_prop_index (key);
  if (idx >= FONT_WEIGHT_INDEX && idx <= FONT_WIDTH_INDEX)
    return font_style_symbolic (font, idx, 0);
  if (idx >= 0 && idx < FONT_EXTRA_INDEX)
    return AREF (font, idx);
  val = Fassq (key, AREF (font, FONT_EXTRA_INDEX));
  if (NILP (val) && FONT_OBJECT_P (font))
    {
      struct font *fontp = XFONT_OBJECT (font);

      if (EQ (key, QCotf))
        {
          if (fontp->driver->otf_capability)
            val = fontp->driver->otf_capability (fontp);
          else
            val = Fcons (Qnil, Qnil);
        }
      else if (EQ (key, QCcombining_capability))
        {
          if (fontp->driver->combining_capability)
            val = fontp->driver->combining_capability (fontp);
        }
    }
  else
    val = Fcdr (val);
  return val;
}

#ifdef HAVE_WINDOW_SYSTEM

DEFUN ("font-face-attributes", Ffont_face_attributes, Sfont_face_attributes, 1, 2, 0,
       doc: /* Return a plist of face attributes generated by FONT.
FONT is a font name, a font-spec, a font-entity, or a font-object.
The return value is a list of the form

\(:family FAMILY :height HEIGHT :weight WEIGHT :slant SLANT :width WIDTH)

where FAMILY, HEIGHT, WEIGHT, SLANT, and WIDTH are face attribute values
compatible with `set-face-attribute'.  Some of these key-attribute pairs
may be omitted from the list if they are not specified by FONT.

The optional argument FRAME specifies the frame that the face attributes
are to be displayed on.  If omitted, the selected frame is used.  */)
  (Lisp_Object font, Lisp_Object frame)
{
  struct frame *f = decode_live_frame (frame);
  Lisp_Object plist[10];
  Lisp_Object val;
  int n = 0;

  if (STRINGP (font))
    {
      int fontset = fs_query_fontset (font, 0);
      Lisp_Object name = font;
      if (fontset >= 0)
        font = fontset_ascii (fontset);
      font = font_spec_from_name (name);
      if (! FONTP (font))
        signal_error ("Invalid font name", name);
    }
  else if (! FONTP (font))
    signal_error ("Invalid font object", font);

  val = AREF (font, FONT_FAMILY_INDEX);
  if (! NILP (val))
    {
      plist[n++] = QCfamily;
      plist[n++] = SYMBOL_NAME (val);
    }

  val = AREF (font, FONT_SIZE_INDEX);
  if (INTEGERP (val))
    {
      Lisp_Object font_dpi = AREF (font, FONT_DPI_INDEX);
      int dpi = INTEGERP (font_dpi) ? XINT (font_dpi) : FRAME_RES_Y (f);
      plist[n++] = QCheight;
      plist[n++] = make_number (PIXEL_TO_POINT (XINT (val) * 10, dpi));
    }
  else if (FLOATP (val))
    {
      plist[n++] = QCheight;
      plist[n++] = make_number (10 * (int) XFLOAT_DATA (val));
    }

  val = FONT_WEIGHT_FOR_FACE (font);
  if (! NILP (val))
    {
      plist[n++] = QCweight;
      plist[n++] = val;
    }

  val = FONT_SLANT_FOR_FACE (font);
  if (! NILP (val))
    {
      plist[n++] = QCslant;
      plist[n++] = val;
    }

  val = FONT_WIDTH_FOR_FACE (font);
  if (! NILP (val))
    {
      plist[n++] = QCwidth;
      plist[n++] = val;
    }

  return Flist (n, plist);
}

#endif

DEFUN ("font-put", Ffont_put, Sfont_put, 3, 3, 0,
       doc: /* Set one property of FONT: give property KEY value VAL.
FONT is a font-spec, a font-entity, or a font-object.

If FONT is a font-spec, KEY can be any symbol.  But if KEY is the one
accepted by the function `font-spec' (which see), VAL must be what
allowed in `font-spec'.

If FONT is a font-entity or a font-object, KEY must not be the one
accepted by `font-spec'.  */)
  (Lisp_Object font, Lisp_Object prop, Lisp_Object val)
{
  int idx;

  idx = get_font_prop_index (prop);
  if (idx >= 0 && idx < FONT_EXTRA_INDEX)
    {
      CHECK_FONT_SPEC (font);
      ASET (font, idx, font_prop_validate (idx, Qnil, val));
    }
  else
    {
      if (EQ (prop, QCname)
          || EQ (prop, QCscript)
          || EQ (prop, QClang)
          || EQ (prop, QCotf))
        CHECK_FONT_SPEC (font);
      else
        CHECK_FONT (font);
      font_put_extra (font, prop, font_prop_validate (0, prop, val));
    }
  return val;
}

DEFUN ("list-fonts", Flist_fonts, Slist_fonts, 1, 4, 0,
       doc: /* List available fonts matching FONT-SPEC on the current frame.
Optional 2nd argument FRAME specifies the target frame.
Optional 3rd argument NUM, if non-nil, limits the number of returned fonts.
Optional 4th argument PREFER, if non-nil, is a font-spec to
control the order of the returned list.  Fonts are sorted by
how close they are to PREFER.  */)
  (Lisp_Object font_spec, Lisp_Object frame, Lisp_Object num, Lisp_Object prefer)
{
  struct frame *f = decode_live_frame (frame);
  Lisp_Object vec, list;
  EMACS_INT n = 0;

  CHECK_FONT_SPEC (font_spec);
  if (! NILP (num))
    {
      CHECK_NUMBER (num);
      n = XINT (num);
      if (n <= 0)
        return Qnil;
    }
  if (! NILP (prefer))
    CHECK_FONT_SPEC (prefer);

  list = font_list_entities (f, font_spec);
  if (NILP (list))
    return Qnil;
  if (NILP (XCDR (list))
      && ASIZE (XCAR (list)) == 1)
    return list1 (AREF (XCAR (list), 0));

  if (! NILP (prefer))
    vec = font_sort_entities (list, prefer, f, 0);
  else
    vec = font_vconcat_entity_vectors (list);
  if (n == 0 || n >= ASIZE (vec))
    list = CALLN (Fappend, vec, Qnil);
  else
    {
      for (list = Qnil, n--; n >= 0; n--)
        list = Fcons (AREF (vec, n), list);
    }
  return list;
}

DEFUN ("font-family-list", Ffont_family_list, Sfont_family_list, 0, 1, 0,
       doc: /* List available font families on the current frame.
If FRAME is omitted or nil, the selected frame is used.  */)
  (Lisp_Object frame)
{
  struct frame *f = decode_live_frame (frame);
  struct font_driver_list *driver_list;
  Lisp_Object list = Qnil;

  for (driver_list = f->font_driver_list; driver_list;
       driver_list = driver_list->next)
    if (driver_list->driver->list_family)
      {
        Lisp_Object val = driver_list->driver->list_family (f);
        Lisp_Object tail = list;

        for (; CONSP (val); val = XCDR (val))
          if (NILP (Fmemq (XCAR (val), tail))
              && SYMBOLP (XCAR (val)))
            list = Fcons (SYMBOL_NAME (XCAR (val)), list);
      }
  return list;
}

DEFUN ("find-font", Ffind_font, Sfind_font, 1, 2, 0,
       doc: /* Return a font-entity matching with FONT-SPEC on the current frame.
Optional 2nd argument FRAME, if non-nil, specifies the target frame.  */)
  (Lisp_Object font_spec, Lisp_Object frame)
{
  Lisp_Object val = Flist_fonts (font_spec, frame, make_number (1), Qnil);

  if (CONSP (val))
    val = XCAR (val);
  return val;
}

DEFUN ("font-xlfd-name", Ffont_xlfd_name, Sfont_xlfd_name, 1, 2, 0,
       doc: /*  Return XLFD name of FONT.
FONT is a font-spec, font-entity, or font-object.
If the name is too long for XLFD (maximum 255 chars), return nil.
If the 2nd optional arg FOLD-WILDCARDS is non-nil,
the consecutive wildcards are folded into one.  */)
  (Lisp_Object font, Lisp_Object fold_wildcards)
{
  char name[256];
  int namelen, pixel_size = 0;

  CHECK_FONT (font);

  if (FONT_OBJECT_P (font))
    {
      Lisp_Object font_name = AREF (font, FONT_NAME_INDEX);

      if (STRINGP (font_name)
          && SDATA (font_name)[0] == '-')
        {
          if (NILP (fold_wildcards))
            return font_name;
          lispstpcpy (name, font_name);
          namelen = SBYTES (font_name);
          goto done;
        }
      pixel_size = XFONT_OBJECT (font)->pixel_size;
    }
  namelen = font_unparse_xlfd (font, pixel_size, name, 256);
  if (namelen < 0)
    return Qnil;
 done:
  if (! NILP (fold_wildcards))
    {
      char *p0 = name, *p1;

      while ((p1 = strstr (p0, "-*-*")))
        {
          strcpy (p1, p1 + 2);
          namelen -= 2;
          p0 = p1;
        }
    }

  return make_string (name, namelen);
}

void
clear_font_cache (struct frame *f)
{
  struct font_driver_list *driver_list = f->font_driver_list;

  for (; driver_list; driver_list = driver_list->next)
    if (driver_list->on)
      {
        Lisp_Object val, tmp, cache = driver_list->driver->get_cache (f);

        val = XCDR (cache);
        while (! NILP (val)
               && ! EQ (XCAR (XCAR (val)), driver_list->driver->type))
          val = XCDR (val);
        eassert (! NILP (val));
        tmp = XCDR (XCAR (val));
        if (XINT (XCAR (tmp)) == 0)
          {
            font_clear_cache (f, XCAR (val), driver_list->driver);
            XSETCDR (cache, XCDR (val));
          }
      }
}

DEFUN ("clear-font-cache", Fclear_font_cache, Sclear_font_cache, 0, 0, 0,
       doc: /* Clear font cache of each frame.  */)
  (void)
{
  Lisp_Object list, frame;

  FOR_EACH_FRAME (list, frame)
    clear_font_cache (XFRAME (frame));

  return Qnil;
}

\f
void
font_fill_lglyph_metrics (Lisp_Object glyph, Lisp_Object font_object)
{
  struct font *font = XFONT_OBJECT (font_object);
  unsigned code = font->driver->encode_char (font, LGLYPH_CHAR (glyph));
  struct font_metrics metrics;

  LGLYPH_SET_CODE (glyph, code);
  font->driver->text_extents (font, &code, 1, &metrics);
  LGLYPH_SET_LBEARING (glyph, metrics.lbearing);
  LGLYPH_SET_RBEARING (glyph, metrics.rbearing);
  LGLYPH_SET_WIDTH (glyph, metrics.width);
  LGLYPH_SET_ASCENT (glyph, metrics.ascent);
  LGLYPH_SET_DESCENT (glyph, metrics.descent);
}


DEFUN ("font-shape-gstring", Ffont_shape_gstring, Sfont_shape_gstring, 1, 1, 0,
       doc: /* Shape the glyph-string GSTRING.
Shaping means substituting glyphs and/or adjusting positions of glyphs
to get the correct visual image of character sequences set in the
header of the glyph-string.

If the shaping was successful, the value is GSTRING itself or a newly
created glyph-string.  Otherwise, the value is nil.

See the documentation of `composition-get-gstring' for the format of
GSTRING.  */)
  (Lisp_Object gstring)
{
  struct font *font;
  Lisp_Object font_object, n, glyph;
  ptrdiff_t i, from, to;

  if (! composition_gstring_p (gstring))
    signal_error ("Invalid glyph-string: ", gstring);
  if (! NILP (LGSTRING_ID (gstring)))
    return gstring;
  font_object = LGSTRING_FONT (gstring);
  CHECK_FONT_OBJECT (font_object);
  font = XFONT_OBJECT (font_object);
  if (! font->driver->shape)
    return Qnil;

  /* Try at most three times with larger gstring each time.  */
  for (i = 0; i < 3; i++)
    {
      n = font->driver->shape (gstring);
      if (INTEGERP (n))
        break;
      gstring = larger_vector (gstring,
                               LGSTRING_GLYPH_LEN (gstring), -1);
    }
  if (i == 3 || XINT (n) == 0)
    return Qnil;
  if (XINT (n) < LGSTRING_GLYPH_LEN (gstring))
    LGSTRING_SET_GLYPH (gstring, XINT (n), Qnil);

  /* Check FROM_IDX and TO_IDX of each GLYPH in GSTRING to assure that
     GLYPHS covers all characters (except for the last few ones) in
     GSTRING.  More formally, provided that NCHARS is the number of
     characters in GSTRING and GLYPHS[i] is the ith glyph, FROM_IDX
     and TO_IDX of each glyph must satisfy these conditions:

       GLYPHS[0].FROM_IDX == 0
       GLYPHS[i].FROM_IDX <= GLYPHS[i].TO_IDX
       if (GLYPHS[i].FROM_IDX == GLYPHS[i-1].FROM_IDX)
         ;; GLYPHS[i] and GLYPHS[i-1] belongs to the same grapheme cluster
         GLYPHS[i].TO_IDX == GLYPHS[i-1].TO_IDX
       else
         ;; Be sure to cover all characters.
         GLYPHS[i].FROM_IDX == GLYPHS[i-1].TO_IDX + 1 */
  glyph = LGSTRING_GLYPH (gstring, 0);
  from = LGLYPH_FROM (glyph);
  to = LGLYPH_TO (glyph);
  if (from != 0 || to < from)
    goto shaper_error;
  for (i = 1; i < LGSTRING_GLYPH_LEN (gstring); i++)
    {
      glyph = LGSTRING_GLYPH (gstring, i);
      if (NILP (glyph))
        break;
      if (! (LGLYPH_FROM (glyph) <= LGLYPH_TO (glyph)
             && (LGLYPH_FROM (glyph) == from
                 ? LGLYPH_TO (glyph) == to
                 : LGLYPH_FROM (glyph) == to + 1)))
        goto shaper_error;
      from = LGLYPH_FROM (glyph);
      to = LGLYPH_TO (glyph);
    }
  return composition_gstring_put_cache (gstring, XINT (n));

 shaper_error:
  return Qnil;
}

DEFUN ("font-variation-glyphs", Ffont_variation_glyphs, Sfont_variation_glyphs,
       2, 2, 0,
       doc: /* Return a list of variation glyphs for CHAR in FONT-OBJECT.
Each element of the value is a cons (VARIATION-SELECTOR . GLYPH-ID),
where
  VARIATION-SELECTOR is a character code of variation selection
    (#xFE00..#xFE0F or #xE0100..#xE01EF)
  GLYPH-ID is a glyph code of the corresponding variation glyph.  */)
  (Lisp_Object font_object, Lisp_Object character)
{
  unsigned variations[256];
  struct font *font;
  int i, n;
  Lisp_Object val;

  CHECK_FONT_OBJECT (font_object);
  CHECK_CHARACTER (character);
  font = XFONT_OBJECT (font_object);
  if (! font->driver->get_variation_glyphs)
    return Qnil;
  n = font->driver->get_variation_glyphs (font, XINT (character), variations);
  if (! n)
    return Qnil;
  val = Qnil;
  for (i = 0; i < 255; i++)
    if (variations[i])
      {
        int vs = (i < 16 ? 0xFE00 + i : 0xE0100 + (i - 16));
        Lisp_Object code = INTEGER_TO_CONS (variations[i]);
        val = Fcons (Fcons (make_number (vs), code), val);
      }
  return val;
}

/* Return a description of the font at POSITION in the current buffer.
   If the 2nd optional arg CH is non-nil, it is a character to check
   the font instead of the character at POSITION.

   For a graphical display, return a cons (FONT-OBJECT . GLYPH-CODE).
   FONT-OBJECT is the font for the character at POSITION in the current
   buffer.  This is computed from all the text properties and overlays
   that apply to POSITION.  POSITION may be nil, in which case,
   FONT-SPEC is the font for displaying the character CH with the
   default face.  GLYPH-CODE is the glyph code in the font to use for
   the character.

   For a text terminal, return a nonnegative integer glyph code for
   the character, or a negative integer if the character is not
   displayable.  Terminal glyph codes are system-dependent integers
   that represent displayable characters: for example, on a Linux x86
   console they represent VGA code points.

   It returns nil in the following cases:

   (1) The window system doesn't have a font for the character (thus
   it is displayed by an empty box).

   (2) The character code is invalid.

   (3) If POSITION is not nil, and the current buffer is not displayed
   in any window.

   (4) For a text terminal, the terminal does not report glyph codes.

   In addition, the returned font name may not take into account of
   such redisplay engine hooks as what used in jit-lock-mode if
   POSITION is currently not visible.  */


DEFUN ("internal-char-font", Finternal_char_font, Sinternal_char_font, 1, 2, 0,
       doc: /* For internal use only.  */)
  (Lisp_Object position, Lisp_Object ch)
{
  ptrdiff_t pos, pos_byte, dummy;
  int face_id;
  int c;
  struct frame *f;

  if (NILP (position))
    {
      CHECK_CHARACTER (ch);
      c = XINT (ch);
      f = XFRAME (selected_frame);
      face_id = lookup_basic_face (f, DEFAULT_FACE_ID);
      pos = -1;
    }
  else
    {
      Lisp_Object window;
      struct window *w;

      CHECK_NUMBER_COERCE_MARKER (position);
      if (! (BEGV <= XINT (position) && XINT (position) < ZV))
        args_out_of_range_3 (position, make_number (BEGV), make_number (ZV));
      pos = XINT (position);
      pos_byte = CHAR_TO_BYTE (pos);
      if (NILP (ch))
        c = FETCH_CHAR (pos_byte);
      else
        {
          CHECK_NATNUM (ch);
          c = XINT (ch);
        }
      window = Fget_buffer_window (Fcurrent_buffer (), Qnil);
      if (NILP (window))
        return Qnil;
      w = XWINDOW (window);
      f = XFRAME (w->frame);
      face_id = face_at_buffer_position (w, pos, &dummy,
                                         pos + 100, false, -1);
    }
  if (! CHAR_VALID_P (c))
    return Qnil;

  if (! FRAME_WINDOW_P (f))
    return terminal_glyph_code (FRAME_TERMINAL (f), c);

  /* We need the basic faces to be valid below, so recompute them if
     some code just happened to clear the face cache.  */
  if (FRAME_FACE_CACHE (f)->used == 0)
    recompute_basic_faces (f);

  face_id = FACE_FOR_CHAR (f, FACE_FROM_ID (f, face_id), c, pos, Qnil);
  struct face *face = FACE_FROM_ID (f, face_id);
  if (! face->font)
    return Qnil;
  unsigned code = face->font->driver->encode_char (face->font, c);
  if (code == FONT_INVALID_CODE)
    return Qnil;
  Lisp_Object font_object;
  XSETFONT (font_object, face->font);
  return Fcons (font_object, INTEGER_TO_CONS (code));
}

#if 0

DEFUN ("font-drive-otf", Ffont_drive_otf, Sfont_drive_otf, 6, 6, 0,
       doc: /* Apply OpenType features on glyph-string GSTRING-IN.
OTF-FEATURES specifies which features to apply in this format:
  (SCRIPT LANGSYS GSUB GPOS)
where
  SCRIPT is a symbol specifying a script tag of OpenType,
  LANGSYS is a symbol specifying a langsys tag of OpenType,
  GSUB and GPOS, if non-nil, are lists of symbols specifying feature tags.

If LANGSYS is nil, the default langsys is selected.

The features are applied in the order they appear in the list.  The
symbol `*' means to apply all available features not present in this
list, and the remaining features are ignored.  For instance, (vatu
pstf * haln) is to apply vatu and pstf in this order, then to apply
all available features other than vatu, pstf, and haln.

The features are applied to the glyphs in the range FROM and TO of
the glyph-string GSTRING-IN.

If some feature is actually applicable, the resulting glyphs are
produced in the glyph-string GSTRING-OUT from the index INDEX.  In
this case, the value is the number of produced glyphs.

If no feature is applicable, no glyph is produced in GSTRING-OUT, and
the value is 0.

If GSTRING-OUT is too short to hold produced glyphs, no glyphs are
produced in GSTRING-OUT, and the value is nil.

See the documentation of `composition-get-gstring' for the format of
glyph-string.  */)
  (Lisp_Object otf_features, Lisp_Object gstring_in, Lisp_Object from, Lisp_Object to, Lisp_Object gstring_out, Lisp_Object index)
{
  Lisp_Object font_object = LGSTRING_FONT (gstring_in);
  Lisp_Object val;
  struct font *font;
  int len, num;

  check_otf_features (otf_features);
  CHECK_FONT_OBJECT (font_object);
  font = XFONT_OBJECT (font_object);
  if (! font->driver->otf_drive)
    error ("Font backend %s can't drive OpenType GSUB table",
           SDATA (SYMBOL_NAME (font->driver->type)));
  CHECK_CONS (otf_features);
  CHECK_SYMBOL (XCAR (otf_features));
  val = XCDR (otf_features);
  CHECK_SYMBOL (XCAR (val));
  val = XCDR (otf_features);
  if (! NILP (val))
    CHECK_CONS (val);
  len = check_gstring (gstring_in);
  CHECK_VECTOR (gstring_out);
  CHECK_NATNUM (from);
  CHECK_NATNUM (to);
  CHECK_NATNUM (index);

  if (XINT (from) >= XINT (to) || XINT (to) > len)
    args_out_of_range_3 (from, to, make_number (len));
  if (XINT (index) >= ASIZE (gstring_out))
    args_out_of_range (index, make_number (ASIZE (gstring_out)));
  num = font->driver->otf_drive (font, otf_features,
                                 gstring_in, XINT (from), XINT (to),
                                 gstring_out, XINT (index), 0);
  if (num < 0)
    return Qnil;
  return make_number (num);
}

DEFUN ("font-otf-alternates", Ffont_otf_alternates, Sfont_otf_alternates,
       3, 3, 0,
       doc: /* Return a list of alternate glyphs of CHARACTER in FONT-OBJECT.
OTF-FEATURES specifies which features of the font FONT-OBJECT to apply
in this format:
  (SCRIPT LANGSYS FEATURE ...)
See the documentation of `font-drive-otf' for more detail.

The value is a list of cons cells of the format (GLYPH-ID . CHARACTER),
where GLYPH-ID is a glyph index of the font, and CHARACTER is a
character code corresponding to the glyph or nil if there's no
corresponding character.  */)
  (Lisp_Object font_object, Lisp_Object character, Lisp_Object otf_features)
{
  struct font *font = CHECK_FONT_GET_OBJECT (font_object);
  Lisp_Object gstring_in, gstring_out, g;
  Lisp_Object alternates;
  int i, num;

  if (! font->driver->otf_drive)
    error ("Font backend %s can't drive OpenType GSUB table",
           SDATA (SYMBOL_NAME (font->driver->type)));
  CHECK_CHARACTER (character);
  CHECK_CONS (otf_features);

  gstring_in = Ffont_make_gstring (font_object, make_number (1));
  g = LGSTRING_GLYPH (gstring_in, 0);
  LGLYPH_SET_CHAR (g, XINT (character));
  gstring_out = Ffont_make_gstring (font_object, make_number (10));
  while ((num = font->driver->otf_drive (font, otf_features, gstring_in, 0, 1,
                                         gstring_out, 0, 1)) < 0)
    gstring_out = Ffont_make_gstring (font_object,
                                      make_number (ASIZE (gstring_out) * 2));
  alternates = Qnil;
  for (i = 0; i < num; i++)
    {
      Lisp_Object g = LGSTRING_GLYPH (gstring_out, i);
      int c = LGLYPH_CHAR (g);
      unsigned code = LGLYPH_CODE (g);

      alternates = Fcons (Fcons (make_number (code),
                                 c > 0 ? make_number (c) : Qnil),
                          alternates);
    }
  return Fnreverse (alternates);
}
#endif  /* 0 */

#ifdef FONT_DEBUG

DEFUN ("open-font", Fopen_font, Sopen_font, 1, 3, 0,
       doc: /* Open FONT-ENTITY.  */)
  (Lisp_Object font_entity, Lisp_Object size, Lisp_Object frame)
{
  EMACS_INT isize;
  struct frame *f = decode_live_frame (frame);

  CHECK_FONT_ENTITY (font_entity);

  if (NILP (size))
    isize = XINT (AREF (font_entity, FONT_SIZE_INDEX));
  else
    {
      CHECK_NUMBER_OR_FLOAT (size);
      if (FLOATP (size))
        isize = POINT_TO_PIXEL (XFLOAT_DATA (size), FRAME_RES_Y (f));
      else
        isize = XINT (size);
      if (! (INT_MIN <= isize && isize <= INT_MAX))
        args_out_of_range (font_entity, size);
      if (isize == 0)
        isize = 120;
    }
  return font_open_entity (f, font_entity, isize);
}

DEFUN ("close-font", Fclose_font, Sclose_font, 1, 2, 0,
       doc: /* Close FONT-OBJECT.  */)
  (Lisp_Object font_object, Lisp_Object frame)
{
  CHECK_FONT_OBJECT (font_object);
  font_close_object (decode_live_frame (frame), font_object);
  return Qnil;
}

DEFUN ("query-font", Fquery_font, Squery_font, 1, 1, 0,
       doc: /* Return information about FONT-OBJECT.
The value is a vector:
  [ NAME FILENAME PIXEL-SIZE SIZE ASCENT DESCENT SPACE-WIDTH AVERAGE-WIDTH
    CAPABILITY ]

NAME is the font name, a string (or nil if the font backend doesn't
provide a name).

FILENAME is the font file name, a string (or nil if the font backend
doesn't provide a file name).

PIXEL-SIZE is a pixel size by which the font is opened.

SIZE is a maximum advance width of the font in pixels.

ASCENT, DESCENT, SPACE-WIDTH, AVERAGE-WIDTH are metrics of the font in
pixels.

CAPABILITY is a list whose first element is a symbol representing the
font format (x, opentype, truetype, type1, pcf, or bdf) and the
remaining elements describe the details of the font capability.

If the font is OpenType font, the form of the list is
  (opentype GSUB GPOS)
where GSUB shows which "GSUB" features the font supports, and GPOS
shows which "GPOS" features the font supports.  Both GSUB and GPOS are
lists of the format:
  ((SCRIPT (LANGSYS FEATURE ...) ...) ...)

If the font is not OpenType font, currently the length of the form is
one.

SCRIPT is a symbol representing OpenType script tag.

LANGSYS is a symbol representing OpenType langsys tag, or nil
representing the default langsys.

FEATURE is a symbol representing OpenType feature tag.

If the font is not OpenType font, CAPABILITY is nil.  */)
  (Lisp_Object font_object)
{
  struct font *font = CHECK_FONT_GET_OBJECT (font_object);
  Lisp_Object val = make_uninit_vector (9);

  ASET (val, 0, AREF (font_object, FONT_NAME_INDEX));
  ASET (val, 1, AREF (font_object, FONT_FILE_INDEX));
  ASET (val, 2, make_number (font->pixel_size));
  ASET (val, 3, make_number (font->max_width));
  ASET (val, 4, make_number (font->ascent));
  ASET (val, 5, make_number (font->descent));
  ASET (val, 6, make_number (font->space_width));
  ASET (val, 7, make_number (font->average_width));
  if (font->driver->otf_capability)
    ASET (val, 8, Fcons (Qopentype, font->driver->otf_capability (font)));
  else
    ASET (val, 8, Qnil);
  return val;
}

DEFUN ("font-get-glyphs", Ffont_get_glyphs, Sfont_get_glyphs, 3, 4, 0,
       doc:
       /* Return a vector of FONT-OBJECT's glyphs for the specified characters.
FROM and TO are positions (integers or markers) specifying a region
of the current buffer, and can be in either order.  If the optional
fourth arg OBJECT is not nil, it is a string or a vector containing
the target characters between indices FROM and TO, which are treated
as in `substring'.

Each element is a vector containing information of a glyph in this format:
  [FROM-IDX TO-IDX C CODE WIDTH LBEARING RBEARING ASCENT DESCENT ADJUSTMENT]
where
  FROM is an index numbers of a character the glyph corresponds to.
  TO is the same as FROM.
  C is the character of the glyph.
  CODE is the glyph-code of C in FONT-OBJECT.
  WIDTH thru DESCENT are the metrics (in pixels) of the glyph.
  ADJUSTMENT is always nil.
If FONT-OBJECT doesn't have a glyph for a character,
the corresponding element is nil.  */)
  (Lisp_Object font_object, Lisp_Object from, Lisp_Object to,
   Lisp_Object object)
{
  struct font *font = CHECK_FONT_GET_OBJECT (font_object);
  ptrdiff_t i, len;
  Lisp_Object *chars, vec;
  USE_SAFE_ALLOCA;

  if (NILP (object))
    {
      ptrdiff_t charpos, bytepos;

      validate_region (&from, &to);
      if (EQ (from, to))
        return Qnil;
      len = XFASTINT (to) - XFASTINT (from);
      SAFE_ALLOCA_LISP (chars, len);
      charpos = XFASTINT (from);
      bytepos = CHAR_TO_BYTE (charpos);
      for (i = 0; charpos < XFASTINT (to); i++)
        {
          int c;
          FETCH_CHAR_ADVANCE (c, charpos, bytepos);
          chars[i] = make_number (c);
        }
    }
  else if (STRINGP (object))
    {
      const unsigned char *p;
      ptrdiff_t ifrom, ito;

      validate_subarray (object, from, to, SCHARS (object), &ifrom, &ito);
      if (ifrom == ito)
        return Qnil;
      len = ito - ifrom;
      SAFE_ALLOCA_LISP (chars, len);
      p = SDATA (object);
      if (STRING_MULTIBYTE (object))
        {
          int c;

          /* Skip IFROM characters from the beginning.  */
          for (i = 0; i < ifrom; i++)
            c = STRING_CHAR_ADVANCE (p);

          /* Now fetch an interesting characters.  */
          for (i = 0; i < len; i++)
          {
            c = STRING_CHAR_ADVANCE (p);
            chars[i] = make_number (c);
          }
        }
      else
        for (i = 0; i < len; i++)
          chars[i] = make_number (p[ifrom + i]);
    }
  else if (VECTORP (object))
    {
      ptrdiff_t ifrom, ito;

      validate_subarray (object, from, to, ASIZE (object), &ifrom, &ito);
      if (ifrom == ito)
        return Qnil;
      len = ito - ifrom;
      for (i = 0; i < len; i++)
        {
          Lisp_Object elt = AREF (object, ifrom + i);
          CHECK_CHARACTER (elt);
        }
      chars = aref_addr (object, ifrom);
    }
  else
    wrong_type_argument (Qarrayp, object);

  vec = make_uninit_vector (len);
  for (i = 0; i < len; i++)
    {
      Lisp_Object g;
      int c = XFASTINT (chars[i]);
      unsigned code;
      struct font_metrics metrics;

      code = font->driver->encode_char (font, c);
      if (code == FONT_INVALID_CODE)
        {
          ASET (vec, i, Qnil);
          continue;
        }
      g = LGLYPH_NEW ();
      LGLYPH_SET_FROM (g, i);
      LGLYPH_SET_TO (g, i);
      LGLYPH_SET_CHAR (g, c);
      LGLYPH_SET_CODE (g, code);
      font->driver->text_extents (font, &code, 1, &metrics);
      LGLYPH_SET_WIDTH (g, metrics.width);
      LGLYPH_SET_LBEARING (g, metrics.lbearing);
      LGLYPH_SET_RBEARING (g, metrics.rbearing);
      LGLYPH_SET_ASCENT (g, metrics.ascent);
      LGLYPH_SET_DESCENT (g, metrics.descent);
      ASET (vec, i, g);
    }
  if (! VECTORP (object))
    SAFE_FREE ();
  return vec;
}

DEFUN ("font-match-p", Ffont_match_p, Sfont_match_p, 2, 2, 0,
       doc: /* Return t if and only if font-spec SPEC matches with FONT.
FONT is a font-spec, font-entity, or font-object. */)
  (Lisp_Object spec, Lisp_Object font)
{
  CHECK_FONT_SPEC (spec);
  CHECK_FONT (font);

  return (font_match_p (spec, font) ? Qt : Qnil);
}

DEFUN ("font-at", Ffont_at, Sfont_at, 1, 3, 0,
       doc: /* Return a font-object for displaying a character at POSITION.
Optional second arg WINDOW, if non-nil, is a window displaying
the current buffer.  It defaults to the currently selected window.
Optional third arg STRING, if non-nil, is a string containing the target
character at index specified by POSITION.  */)
  (Lisp_Object position, Lisp_Object window, Lisp_Object string)
{
  struct window *w = decode_live_window (window);

  if (NILP (string))
    {
      if (XBUFFER (w->contents) != current_buffer)
        error ("Specified window is not displaying the current buffer");
      CHECK_NUMBER_COERCE_MARKER (position);
      if (! (BEGV <= XINT (position) && XINT (position) < ZV))
        args_out_of_range_3 (position, make_number (BEGV), make_number (ZV));
    }
  else
    {
      CHECK_NUMBER (position);
      CHECK_STRING (string);
      if (! (0 <= XINT (position) && XINT (position) < SCHARS (string)))
        args_out_of_range (string, position);
    }

  return font_at (-1, XINT (position), NULL, w, string);
}

#if 0
DEFUN ("draw-string", Fdraw_string, Sdraw_string, 2, 2, 0,
       doc: /*  Draw STRING by FONT-OBJECT on the top left corner of the current frame.
The value is a number of glyphs drawn.
Type C-l to recover what previously shown.  */)
  (Lisp_Object font_object, Lisp_Object string)
{
  Lisp_Object frame = selected_frame;
  struct frame *f = XFRAME (frame);
  struct font *font;
  struct face *face;
  int i, len, width;
  unsigned *code;

  CHECK_FONT_GET_OBJECT (font_object, font);
  CHECK_STRING (string);
  len = SCHARS (string);
  code = alloca (sizeof (unsigned) * len);
  for (i = 0; i < len; i++)
    {
      Lisp_Object ch = Faref (string, make_number (i));
      Lisp_Object val;
      int c = XINT (ch);

      code[i] = font->driver->encode_char (font, c);
      if (code[i] == FONT_INVALID_CODE)
        break;
    }
  face = FACE_FROM_ID (f, DEFAULT_FACE_ID);
  face->fontp = font;
  if (font->driver->prepare_face)
    font->driver->prepare_face (f, face);
  width = font->driver->text_extents (font, code, i, NULL);
  len = font->driver->draw_text (f, face, 0, font->ascent, code, i, width);
  if (font->driver->done_face)
    font->driver->done_face (f, face);
  face->fontp = NULL;
  return make_number (len);
}
#endif

DEFUN ("frame-font-cache", Fframe_font_cache, Sframe_font_cache, 0, 1, 0,
       doc: /* Return FRAME's font cache.  Mainly used for debugging.
If FRAME is omitted or nil, use the selected frame.  */)
  (Lisp_Object frame)
{
#ifdef HAVE_WINDOW_SYSTEM
  struct frame *f = decode_live_frame (frame);

  if (FRAME_WINDOW_P (f))
    return FRAME_DISPLAY_INFO (f)->name_list_element;
  else
#endif
    return Qnil;
}

#endif  /* FONT_DEBUG */

#ifdef HAVE_WINDOW_SYSTEM

DEFUN ("font-info", Ffont_info, Sfont_info, 1, 2, 0,
       doc: /* Return information about a font named NAME on frame FRAME.
If FRAME is omitted or nil, use the selected frame.

The returned value is a vector of 14 elements:
  [ OPENED-NAME FULL-NAME SIZE HEIGHT BASELINE-OFFSET RELATIVE-COMPOSE
    DEFAULT-ASCENT MAX-WIDTH ASCENT DESCENT SPACE-WIDTH AVERAGE-WIDTH
    FILENAME CAPABILITY ]
where
  OPENED-NAME is the name used for opening the font,
  FULL-NAME is the full name of the font,
  SIZE is the pixelsize of the font,
  HEIGHT is the pixel-height of the font (i.e., ascent + descent),
  BASELINE-OFFSET is the upward offset pixels from ASCII baseline,
  RELATIVE-COMPOSE and DEFAULT-ASCENT are the numbers controlling
    how to compose characters,
  MAX-WIDTH is the maximum advance width of the font,
  ASCENT, DESCENT, SPACE-WIDTH, and AVERAGE-WIDTH are metrics of
    the font in pixels,
  FILENAME is the font file name, a string (or nil if the font backend
    doesn't provide a file name).
  CAPABILITY is a list whose first element is a symbol representing the
    font format, one of `x', `opentype', `truetype', `type1', `pcf', or `bdf'.
    The remaining elements describe the details of the font capabilities,
    as follows:

      If the font is OpenType font, the form of the list is
        (opentype GSUB GPOS)
      where GSUB shows which "GSUB" features the font supports, and GPOS
      shows which "GPOS" features the font supports.  Both GSUB and GPOS are
      lists of the form:
        ((SCRIPT (LANGSYS FEATURE ...) ...) ...)

      where
        SCRIPT is a symbol representing OpenType script tag.
        LANGSYS is a symbol representing OpenType langsys tag, or nil
         representing the default langsys.
        FEATURE is a symbol representing OpenType feature tag.

      If the font is not an OpenType font, there are no elements
      in CAPABILITY except the font format symbol.

If the named font is not yet loaded, return nil.  */)
  (Lisp_Object name, Lisp_Object frame)
{
  struct frame *f;
  struct font *font;
  Lisp_Object info;
  Lisp_Object font_object;

  if (! FONTP (name))
    CHECK_STRING (name);
  f = decode_window_system_frame (frame);

  if (STRINGP (name))
    {
      int fontset = fs_query_fontset (name, 0);

      if (fontset >= 0)
        name = fontset_ascii (fontset);
      font_object = font_open_by_name (f, name);
    }
  else if (FONT_OBJECT_P (name))
    font_object = name;
  else if (FONT_ENTITY_P (name))
    font_object = font_open_entity (f, name, 0);
  else
    {
      struct face *face = FACE_FROM_ID (f, DEFAULT_FACE_ID);
      Lisp_Object entity = font_matching_entity (f, face->lface, name);

      font_object = ! NILP (entity) ? font_open_entity (f, entity, 0) : Qnil;
    }
  if (NILP (font_object))
    return Qnil;
  font = XFONT_OBJECT (font_object);

  info = make_uninit_vector (14);
  ASET (info, 0, AREF (font_object, FONT_NAME_INDEX));
  ASET (info, 1, AREF (font_object, FONT_FULLNAME_INDEX));
  ASET (info, 2, make_number (font->pixel_size));
  ASET (info, 3, make_number (font->height));
  ASET (info, 4, make_number (font->baseline_offset));
  ASET (info, 5, make_number (font->relative_compose));
  ASET (info, 6, make_number (font->default_ascent));
  ASET (info, 7, make_number (font->max_width));
  ASET (info, 8, make_number (font->ascent));
  ASET (info, 9, make_number (font->descent));
  ASET (info, 10, make_number (font->space_width));
  ASET (info, 11, make_number (font->average_width));
  ASET (info, 12, AREF (font_object, FONT_FILE_INDEX));
  if (font->driver->otf_capability)
    ASET (info, 13, Fcons (Qopentype, font->driver->otf_capability (font)));
  else
    ASET (info, 13, Qnil);

#if 0
  /* As font_object is still in FONT_OBJLIST of the entity, we can't
     close it now.  Perhaps, we should manage font-objects
     by `reference-count'.  */
  font_close_object (f, font_object);
#endif
  return info;
}
#endif

\f
#define BUILD_STYLE_TABLE(TBL) build_style_table (TBL, ARRAYELTS (TBL))

static Lisp_Object
build_style_table (const struct table_entry *entry, int nelement)
{
  int i, j;
  Lisp_Object table, elt;

  table = make_uninit_vector (nelement);
  for (i = 0; i < nelement; i++)
    {
      for (j = 0; entry[i].names[j]; j++);
      elt = Fmake_vector (make_number (j + 1), Qnil);
      ASET (elt, 0, make_number (entry[i].numeric));
      for (j = 0; entry[i].names[j]; j++)
        ASET (elt, j + 1, intern_c_string (entry[i].names[j]));
      ASET (table, i, elt);
    }
  return table;
}

/* The deferred font-log data of the form [ACTION ARG RESULT].
   If ACTION is not nil, that is added to the log when font_add_log is
   called next time.  At that time, ACTION is set back to nil.  */
static Lisp_Object Vfont_log_deferred;

/* Prepend the font-related logging data in Vfont_log if it is not
   t.  ACTION describes a kind of font-related action (e.g. listing,
   opening), ARG is the argument for the action, and RESULT is the
   result of the action.  */
void
font_add_log (const char *action, Lisp_Object arg, Lisp_Object result)
{
  Lisp_Object val;
  int i;

  if (EQ (Vfont_log, Qt))
    return;
  if (STRINGP (AREF (Vfont_log_deferred, 0)))
    {
      char *str = SSDATA (AREF (Vfont_log_deferred, 0));

      ASET (Vfont_log_deferred, 0, Qnil);
      font_add_log (str, AREF (Vfont_log_deferred, 1),
                    AREF (Vfont_log_deferred, 2));
    }

  if (FONTP (arg))
    {
      Lisp_Object tail, elt;
      AUTO_STRING (equal, "=");

      val = Ffont_xlfd_name (arg, Qt);
      for (tail = AREF (arg, FONT_EXTRA_INDEX); CONSP (tail);
           tail = XCDR (tail))
        {
          elt = XCAR (tail);
          if (EQ (XCAR (elt), QCscript)
              && SYMBOLP (XCDR (elt)))
            val = concat3 (val, SYMBOL_NAME (QCscript),
                           concat2 (equal, SYMBOL_NAME (XCDR (elt))));
          else if (EQ (XCAR (elt), QClang)
                   && SYMBOLP (XCDR (elt)))
            val = concat3 (val, SYMBOL_NAME (QClang),
                           concat2 (equal, SYMBOL_NAME (XCDR (elt))));
          else if (EQ (XCAR (elt), QCotf)
                   && CONSP (XCDR (elt)) && SYMBOLP (XCAR (XCDR (elt))))
            val = concat3 (val, SYMBOL_NAME (QCotf),
                           concat2 (equal, SYMBOL_NAME (XCAR (XCDR (elt)))));
        }
      arg = val;
    }

  if (CONSP (result)
      && VECTORP (XCAR (result))
      && ASIZE (XCAR (result)) > 0
      && FONTP (AREF (XCAR (result), 0)))
    result = font_vconcat_entity_vectors (result);
  if (FONTP (result))
    {
      val = Ffont_xlfd_name (result, Qt);
      if (! FONT_SPEC_P (result))
        {
          AUTO_STRING (colon, ":");
          val = concat3 (SYMBOL_NAME (AREF (result, FONT_TYPE_INDEX)),
                         colon, val);
        }
      result = val;
    }
  else if (CONSP (result))
    {
      Lisp_Object tail;
      result = Fcopy_sequence (result);
      for (tail = result; CONSP (tail); tail = XCDR (tail))
        {
          val = XCAR (tail);
          if (FONTP (val))
            val = Ffont_xlfd_name (val, Qt);
          XSETCAR (tail, val);
        }
    }
  else if (VECTORP (result))
    {
      result = Fcopy_sequence (result);
      for (i = 0; i < ASIZE (result); i++)
        {
          val = AREF (result, i);
          if (FONTP (val))
            val = Ffont_xlfd_name (val, Qt);
          ASET (result, i, val);
        }
    }
  Vfont_log = Fcons (list3 (intern (action), arg, result), Vfont_log);
}

/* Record a font-related logging data to be added to Vfont_log when
   font_add_log is called next time.  ACTION, ARG, RESULT are the same
   as font_add_log.  */

void
font_deferred_log (const char *action, Lisp_Object arg, Lisp_Object result)
{
  if (EQ (Vfont_log, Qt))
    return;
  ASET (Vfont_log_deferred, 0, build_string (action));
  ASET (Vfont_log_deferred, 1, arg);
  ASET (Vfont_log_deferred, 2, result);
}

void
font_drop_xrender_surfaces (struct frame *f)
{
  struct font_driver_list *list;

  for (list = f->font_driver_list; list; list = list->next)
    if (list->on && list->driver->drop_xrender_surfaces)
      list->driver->drop_xrender_surfaces (f);
}

void
syms_of_font (void)
{
  sort_shift_bits[FONT_TYPE_INDEX] = 0;
  sort_shift_bits[FONT_SLANT_INDEX] = 2;
  sort_shift_bits[FONT_WEIGHT_INDEX] = 9;
  sort_shift_bits[FONT_SIZE_INDEX] = 16;
  sort_shift_bits[FONT_WIDTH_INDEX] = 23;
  /* Note that the other elements in sort_shift_bits are not used.  */

  staticpro (&font_charset_alist);
  font_charset_alist = Qnil;

  DEFSYM (Qopentype, "opentype");

  /* Important character set symbols.  */
  DEFSYM (Qascii_0, "ascii-0");
  DEFSYM (Qiso8859_1, "iso8859-1");
  DEFSYM (Qiso10646_1, "iso10646-1");
  DEFSYM (Qunicode_bmp, "unicode-bmp");

  /* Symbols representing keys of font extra info.  */
  DEFSYM (QCotf, ":otf");
  DEFSYM (QClang, ":lang");
  DEFSYM (QCscript, ":script");
  DEFSYM (QCantialias, ":antialias");
  DEFSYM (QCfoundry, ":foundry");
  DEFSYM (QCadstyle, ":adstyle");
  DEFSYM (QCregistry, ":registry");
  DEFSYM (QCspacing, ":spacing");
  DEFSYM (QCdpi, ":dpi");
  DEFSYM (QCscalable, ":scalable");
  DEFSYM (QCavgwidth, ":avgwidth");
  DEFSYM (QCfont_entity, ":font-entity");
  DEFSYM (QCcombining_capability, ":combining-capability");

  /* Symbols representing values of font spacing property.  */
  DEFSYM (Qc, "c");
  DEFSYM (Qm, "m");
  DEFSYM (Qp, "p");
  DEFSYM (Qd, "d");

  /* Special ADSTYLE properties to avoid fonts used for Latin
     characters; used in xfont.c and ftfont.c.  */
  DEFSYM (Qja, "ja");
  DEFSYM (Qko, "ko");

  DEFSYM (QCuser_spec, ":user-spec");

  staticpro (&scratch_font_spec);
  scratch_font_spec = Ffont_spec (0, NULL);
  staticpro (&scratch_font_prefer);
  scratch_font_prefer = Ffont_spec (0, NULL);

  staticpro (&Vfont_log_deferred);
  Vfont_log_deferred = Fmake_vector (make_number (3), Qnil);

#if 0
#ifdef HAVE_LIBOTF
  staticpro (&otf_list);
  otf_list = Qnil;
#endif  /* HAVE_LIBOTF */
#endif  /* 0 */

  defsubr (&Sfontp);
  defsubr (&Sfont_spec);
  defsubr (&Sfont_get);
#ifdef HAVE_WINDOW_SYSTEM
  defsubr (&Sfont_face_attributes);
#endif
  defsubr (&Sfont_put);
  defsubr (&Slist_fonts);
  defsubr (&Sfont_family_list);
  defsubr (&Sfind_font);
  defsubr (&Sfont_xlfd_name);
  defsubr (&Sclear_font_cache);
  defsubr (&Sfont_shape_gstring);
  defsubr (&Sfont_variation_glyphs);
  defsubr (&Sinternal_char_font);
#if 0
  defsubr (&Sfont_drive_otf);
  defsubr (&Sfont_otf_alternates);
#endif  /* 0 */

#ifdef FONT_DEBUG
  defsubr (&Sopen_font);
  defsubr (&Sclose_font);
  defsubr (&Squery_font);
  defsubr (&Sfont_get_glyphs);
  defsubr (&Sfont_match_p);
  defsubr (&Sfont_at);
#if 0
  defsubr (&Sdraw_string);
#endif
  defsubr (&Sframe_font_cache);
#endif  /* FONT_DEBUG */
#ifdef HAVE_WINDOW_SYSTEM
  defsubr (&Sfont_info);
#endif

  DEFVAR_LISP ("font-encoding-alist", Vfont_encoding_alist,
               doc: /*
Alist of fontname patterns vs the corresponding encoding and repertory info.
Each element looks like (REGEXP . (ENCODING . REPERTORY)),
where ENCODING is a charset or a char-table,
and REPERTORY is a charset, a char-table, or nil.

If ENCODING and REPERTORY are the same, the element can have the form
\(REGEXP . ENCODING).

ENCODING is for converting a character to a glyph code of the font.
If ENCODING is a charset, encoding a character by the charset gives
the corresponding glyph code.  If ENCODING is a char-table, looking up
the table by a character gives the corresponding glyph code.

REPERTORY specifies a repertory of characters supported by the font.
If REPERTORY is a charset, all characters belonging to the charset are
supported.  If REPERTORY is a char-table, all characters who have a
non-nil value in the table are supported.  If REPERTORY is nil, Emacs
gets the repertory information by an opened font and ENCODING.  */);
  Vfont_encoding_alist = Qnil;

  /* FIXME: These 3 vars are not quite what they appear: setq on them
     won't have any effect other than disconnect them from the style
     table used by the font display code.  So we make them read-only,
     to avoid this confusing situation.  */

  DEFVAR_LISP_NOPRO ("font-weight-table", Vfont_weight_table,
               doc: /*  Vector of valid font weight values.
Each element has the form:
    [NUMERIC-VALUE SYMBOLIC-NAME ALIAS-NAME ...]
NUMERIC-VALUE is an integer, and SYMBOLIC-NAME and ALIAS-NAME are symbols.
This variable cannot be set; trying to do so will signal an error.  */);
  Vfont_weight_table = BUILD_STYLE_TABLE (weight_table);
  make_symbol_constant (intern_c_string ("font-weight-table"));

  DEFVAR_LISP_NOPRO ("font-slant-table", Vfont_slant_table,
               doc: /*  Vector of font slant symbols vs the corresponding numeric values.
See `font-weight-table' for the format of the vector.
This variable cannot be set; trying to do so will signal an error.  */);
  Vfont_slant_table = BUILD_STYLE_TABLE (slant_table);
  make_symbol_constant (intern_c_string ("font-slant-table"));

  DEFVAR_LISP_NOPRO ("font-width-table", Vfont_width_table,
               doc: /*  Alist of font width symbols vs the corresponding numeric values.
See `font-weight-table' for the format of the vector.
This variable cannot be set; trying to do so will signal an error.  */);
  Vfont_width_table = BUILD_STYLE_TABLE (width_table);
  make_symbol_constant (intern_c_string ("font-width-table"));

  staticpro (&font_style_table);
  font_style_table = make_uninit_vector (3);
  ASET (font_style_table, 0, Vfont_weight_table);
  ASET (font_style_table, 1, Vfont_slant_table);
  ASET (font_style_table, 2, Vfont_width_table);

  DEFVAR_LISP ("font-log", Vfont_log, doc: /*
A list that logs font-related actions and results, for debugging.
The default value is t, which means to suppress logging.
Set it to nil to enable logging.  If the environment variable
EMACS_FONT_LOG is set at startup, it defaults to nil.  */);
  Vfont_log = Qnil;

  DEFVAR_BOOL ("inhibit-compacting-font-caches", inhibit_compacting_font_caches,
               doc: /*
If non-nil, don't compact font caches during GC.
Some large fonts cause lots of consing and trigger GC.  If they
are removed from the font caches, they will need to be opened
again during redisplay, which slows down redisplay.  If you
see font-related delays in displaying some special characters,
and cannot switch to a smaller font for those characters, set
this variable non-nil.
Disabling compaction of font caches might enlarge the Emacs memory
footprint in sessions that use lots of different fonts.  */);
  inhibit_compacting_font_caches = 0;

#ifdef HAVE_WINDOW_SYSTEM
#ifdef HAVE_FREETYPE
  syms_of_ftfont ();
#ifdef HAVE_X_WINDOWS
#ifdef USE_CAIRO
  syms_of_ftcrfont ();
#else
  syms_of_xfont ();
  syms_of_ftxfont ();
#ifdef HAVE_XFT
  syms_of_xftfont ();
#endif  /* HAVE_XFT */
#endif  /* not USE_CAIRO */
#endif  /* HAVE_X_WINDOWS */
#else   /* not HAVE_FREETYPE */
#ifdef HAVE_X_WINDOWS
  syms_of_xfont ();
#endif  /* HAVE_X_WINDOWS */
#endif  /* not HAVE_FREETYPE */
#ifdef HAVE_BDFFONT
  syms_of_bdffont ();
#endif  /* HAVE_BDFFONT */
#ifdef HAVE_NTGUI
  syms_of_w32font ();
#endif  /* HAVE_NTGUI */
#endif  /* HAVE_WINDOW_SYSTEM */
}

void
init_font (void)
{
  Vfont_log = egetenv ("EMACS_FONT_LOG") ? Qnil : Qt;
}