/*

 * Copyright © 2011,2012,2013  Google, Inc.

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 *

 * Google Author(s): Behdad Esfahbod

 */

#define HB_SHAPER uniscribe

#include "hb-shaper-impl-private.hh"

#include <windows.h>

#include <usp10.h>

#include <rpc.h>

#include "hb-uniscribe.h"

#include "hb-open-file-private.hh"

#include "hb-ot-name-table.hh"

#include "hb-ot-tag.h"

#ifndef HB_DEBUG_UNISCRIBE

#define HB_DEBUG_UNISCRIBE (HB_DEBUG+0)

#endif

static inline uint16_t hb_uint16_swap (const uint16_t v)

{ return (v >> 8) | (v << 8); }

static inline uint32_t hb_uint32_swap (const uint32_t v)

{ return (hb_uint16_swap (v) << 16) | hb_uint16_swap (v >> 16); }

typedef HRESULT (WINAPI *SIOT) /*ScriptItemizeOpenType*/(

  const WCHAR *pwcInChars,

  int cInChars,

  int cMaxItems,

  const SCRIPT_CONTROL *psControl,

  const SCRIPT_STATE *psState,

  SCRIPT_ITEM *pItems,

  OPENTYPE_TAG *pScriptTags,

  int *pcItems

);

typedef HRESULT (WINAPI *SSOT) /*ScriptShapeOpenType*/(

  HDC hdc,

  SCRIPT_CACHE *psc,

  SCRIPT_ANALYSIS *psa,

  OPENTYPE_TAG tagScript,

  OPENTYPE_TAG tagLangSys,

  int *rcRangeChars,

  TEXTRANGE_PROPERTIES **rpRangeProperties,

  int cRanges,

  const WCHAR *pwcChars,

  int cChars,

  int cMaxGlyphs,

  WORD *pwLogClust,

  SCRIPT_CHARPROP *pCharProps,

  WORD *pwOutGlyphs,

  SCRIPT_GLYPHPROP *pOutGlyphProps,

  int *pcGlyphs

);

typedef HRESULT (WINAPI *SPOT) /*ScriptPlaceOpenType*/(

  HDC hdc,

  SCRIPT_CACHE *psc,

  SCRIPT_ANALYSIS *psa,

  OPENTYPE_TAG tagScript,

  OPENTYPE_TAG tagLangSys,

  int *rcRangeChars,

  TEXTRANGE_PROPERTIES **rpRangeProperties,

  int cRanges,

  const WCHAR *pwcChars,

  WORD *pwLogClust,

  SCRIPT_CHARPROP *pCharProps,

  int cChars,

  const WORD *pwGlyphs,

  const SCRIPT_GLYPHPROP *pGlyphProps,

  int cGlyphs,

  int *piAdvance,

  GOFFSET *pGoffset,

  ABC *pABC

);

/* Fallback implementations. */

static HRESULT WINAPI

hb_ScriptItemizeOpenType(

  const WCHAR *pwcInChars,

  int cInChars,

  int cMaxItems,

  const SCRIPT_CONTROL *psControl,

  const SCRIPT_STATE *psState,

  SCRIPT_ITEM *pItems,

  OPENTYPE_TAG *pScriptTags,

  int *pcItems

)

{

{

  return ScriptItemize (pwcInChars,

			cInChars,

			cMaxItems,

			psControl,

			psState,

			pItems,

			pcItems);

}

}

static HRESULT WINAPI

hb_ScriptShapeOpenType(

  HDC hdc,

  SCRIPT_CACHE *psc,

  SCRIPT_ANALYSIS *psa,

  OPENTYPE_TAG tagScript,

  OPENTYPE_TAG tagLangSys,

  int *rcRangeChars,

  TEXTRANGE_PROPERTIES **rpRangeProperties,

  int cRanges,

  const WCHAR *pwcChars,

  int cChars,

  int cMaxGlyphs,

  WORD *pwLogClust,

  SCRIPT_CHARPROP *pCharProps,

  WORD *pwOutGlyphs,

  SCRIPT_GLYPHPROP *pOutGlyphProps,

  int *pcGlyphs

)

{

  SCRIPT_VISATTR *psva = (SCRIPT_VISATTR *) pOutGlyphProps;

  return ScriptShape (hdc,

		      psc,

		      pwcChars,

		      cChars,

		      cMaxGlyphs,

		      psa,

		      pwOutGlyphs,

		      pwLogClust,

		      psva,

		      pcGlyphs);

}

static HRESULT WINAPI

hb_ScriptPlaceOpenType(

  HDC hdc,

  SCRIPT_CACHE *psc,

  SCRIPT_ANALYSIS *psa,

  OPENTYPE_TAG tagScript,

  OPENTYPE_TAG tagLangSys,

  int *rcRangeChars,

  TEXTRANGE_PROPERTIES **rpRangeProperties,

  int cRanges,

  const WCHAR *pwcChars,

  WORD *pwLogClust,

  SCRIPT_CHARPROP *pCharProps,

  int cChars,

  const WORD *pwGlyphs,

  const SCRIPT_GLYPHPROP *pGlyphProps,

  int cGlyphs,

  int *piAdvance,

  GOFFSET *pGoffset,

  ABC *pABC

)

{

  SCRIPT_VISATTR *psva = (SCRIPT_VISATTR *) pGlyphProps;

  return ScriptPlace (hdc,

		      psc,

		      pwGlyphs,

		      cGlyphs,

		      psva,

		      psa,

		      piAdvance,

		      pGoffset,

		      pABC);

}

struct hb_uniscribe_shaper_funcs_t {

  SIOT ScriptItemizeOpenType;

  SSOT ScriptShapeOpenType;

  SPOT ScriptPlaceOpenType;

  inline void init (void)

  {

    HMODULE hinstLib;

    this->ScriptItemizeOpenType = NULL;

    this->ScriptShapeOpenType   = NULL;

    this->ScriptPlaceOpenType   = NULL;

    hinstLib = GetModuleHandle (TEXT ("usp10.dll"));

    if (hinstLib)

    {

      this->ScriptItemizeOpenType = (SIOT) GetProcAddress (hinstLib, "ScriptItemizeOpenType");

      this->ScriptShapeOpenType   = (SSOT) GetProcAddress (hinstLib, "ScriptShapeOpenType");

      this->ScriptPlaceOpenType   = (SPOT) GetProcAddress (hinstLib, "ScriptPlaceOpenType");

    }

    if (!this->ScriptItemizeOpenType ||

	!this->ScriptShapeOpenType   ||

	!this->ScriptPlaceOpenType)

    {

      DEBUG_MSG (UNISCRIBE, NULL, "OpenType versions of functions not found; falling back.");

      this->ScriptItemizeOpenType = hb_ScriptItemizeOpenType;

      this->ScriptShapeOpenType   = hb_ScriptShapeOpenType;

      this->ScriptPlaceOpenType   = hb_ScriptPlaceOpenType;

    }

  }

};

static hb_uniscribe_shaper_funcs_t *uniscribe_funcs;

static inline void

free_uniscribe_funcs (void)

{

  free (uniscribe_funcs);

}

static hb_uniscribe_shaper_funcs_t *

hb_uniscribe_shaper_get_funcs (void)

{

retry:

  hb_uniscribe_shaper_funcs_t *funcs = (hb_uniscribe_shaper_funcs_t *) hb_atomic_ptr_get (&uniscribe_funcs);

  if (unlikely (!funcs))

  {

    funcs = (hb_uniscribe_shaper_funcs_t *) calloc (1, sizeof (hb_uniscribe_shaper_funcs_t));

    if (unlikely (!funcs))

      return NULL;

    funcs->init ();

    if (!hb_atomic_ptr_cmpexch (&uniscribe_funcs, NULL, funcs)) {

      free (funcs);

      goto retry;

    }

#ifdef HB_USE_ATEXIT

    atexit (free_uniscribe_funcs); /* First person registers atexit() callback. */

#endif

  }

  return funcs;

}

struct active_feature_t {

  OPENTYPE_FEATURE_RECORD rec;

  unsigned int order;

  static int cmp (const active_feature_t *a, const active_feature_t *b) {

    return a->rec.tagFeature < b->rec.tagFeature ? -1 : a->rec.tagFeature > b->rec.tagFeature ? 1 :

	   a->order < b->order ? -1 : a->order > b->order ? 1 :

	   a->rec.lParameter < b->rec.lParameter ? -1 : a->rec.lParameter > b->rec.lParameter ? 1 :

	   0;

  }

  bool operator== (const active_feature_t *f) {

    return cmp (this, f) == 0;

  }

};

struct feature_event_t {

  unsigned int index;

  bool start;

  active_feature_t feature;

  static int cmp (const feature_event_t *a, const feature_event_t *b) {

    return a->index < b->index ? -1 : a->index > b->index ? 1 :

	   a->start < b->start ? -1 : a->start > b->start ? 1 :

	   active_feature_t::cmp (&a->feature, &b->feature);

  }

};

struct range_record_t {

  TEXTRANGE_PROPERTIES props;

  unsigned int index_first; /* == start */

  unsigned int index_last;  /* == end - 1 */

};

HB_SHAPER_DATA_ENSURE_DEFINE(uniscribe, face)

HB_SHAPER_DATA_ENSURE_DEFINE(uniscribe, font)

/*

 * shaper face data

 */

struct hb_uniscribe_shaper_face_data_t {

  HANDLE fh;

  hb_uniscribe_shaper_funcs_t *funcs;

  wchar_t face_name[LF_FACESIZE];

};

/* face_name should point to a wchar_t[LF_FACESIZE] object. */

static void

_hb_generate_unique_face_name (wchar_t *face_name, unsigned int *plen)

{

  /* We'll create a private name for the font from a UUID using a simple,

   * somewhat base64-like encoding scheme */

  const char *enc = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-";

  UUID id;

  UuidCreate ((UUID*) &id;;

  ASSERT_STATIC (2 + 3 * (16/2) < LF_FACESIZE);

  unsigned int name_str_len = 0;

  face_name[name_str_len++] = 'F';

  face_name[name_str_len++] = '_';

  unsigned char *p = (unsigned char *) &id;

  for (unsigned int i = 0; i < 16; i += 2)

  {

    /* Spread the 16 bits from two bytes of the UUID across three chars of face_name,

     * using the bits in groups of 5,5,6 to select chars from enc.

     * This will generate 24 characters; with the 'F_' prefix we already provided,

     * the name will be 26 chars (plus the NUL terminator), so will always fit within

     * face_name (LF_FACESIZE = 32). */

    face_name[name_str_len++] = enc[p[i] >> 3];

    face_name[name_str_len++] = enc[((p[i] << 2) | (p[i + 1] >> 6)) & 0x1f];

    face_name[name_str_len++] = enc[p[i + 1] & 0x3f];

  }

  face_name[name_str_len] = 0;

  if (plen)

    *plen = name_str_len;

}

/* Destroys blob. */

static hb_blob_t *

_hb_rename_font (hb_blob_t *blob, wchar_t *new_name)

{

  /* Create a copy of the font data, with the 'name' table replaced by a

   * table that names the font with our private F_* name created above.

   * For simplicity, we just append a new 'name' table and update the

   * sfnt directory; the original table is left in place, but unused.

   *

   * The new table will contain just 5 name IDs: family, style, unique,

   * full, PS. All of them point to the same name data with our unique name.

   */

  blob = OT::Sanitizer<OT::OpenTypeFontFile>::sanitize (blob);

  unsigned int length, new_length, name_str_len;

  const char *orig_sfnt_data = hb_blob_get_data (blob, &length);

  _hb_generate_unique_face_name (new_name, &name_str_len);

  static const uint16_t name_IDs[] = { 1, 2, 3, 4, 6 };

  unsigned int name_table_length = OT::name::min_size +

                                   ARRAY_LENGTH (name_IDs) * OT::NameRecord::static_size +

                                   name_str_len * 2; /* for name data in UTF16BE form */

  unsigned int name_table_offset = (length + 3) & ~3;

  new_length = name_table_offset + ((name_table_length + 3) & ~3);

  void *new_sfnt_data = calloc (1, new_length);

  if (!new_sfnt_data)

  {

    hb_blob_destroy (blob);

    return NULL;

  }

  memcpy(new_sfnt_data, orig_sfnt_data, length);

  OT::name &name = OT::StructAtOffset<OT::name> (new_sfnt_data, name_table_offset);

  name.format.set (0);

  name.count.set (ARRAY_LENGTH (name_IDs));

  name.stringOffset.set (name.get_size ());

  for (unsigned int i = 0; i < ARRAY_LENGTH (name_IDs); i++)

  {

    OT::NameRecord &record = name.nameRecord[i];

    record.platformID.set (3);

    record.encodingID.set (1);

    record.languageID.set (0x0409u); /* English */

    record.nameID.set (name_IDs[i]);

    record.length.set (name_str_len * 2);

    record.offset.set (0);

  }

  /* Copy string data from new_name, converting wchar_t to UTF16BE. */

  unsigned char *p = &OT::StructAfter<unsigned char> (name);

  for (unsigned int i = 0; i < name_str_len; i++)

  {

    *p++ = new_name[i] >> 8;

    *p++ = new_name[i] & 0xff;

  }

  /* Adjust name table entry to point to new name table */

  const OT::OpenTypeFontFile &file = * (OT::OpenTypeFontFile *) (new_sfnt_data);

  unsigned int face_count = file.get_face_count ();

  for (unsigned int face_index = 0; face_index < face_count; face_index++)

  {

    /* Note: doing multiple edits (ie. TTC) can be unsafe.  There may be

     * toe-stepping.  But we don't really care. */

    const OT::OpenTypeFontFace &face = file.get_face (face_index);

    unsigned int index;

    if (face.find_table_index (HB_OT_TAG_name, &index))

    {

      OT::TableRecord &record = const_cast<OT::TableRecord &> (face.get_table (index));

      record.checkSum.set_for_data (&name, name_table_length);

      record.offset.set (name_table_offset);

      record.length.set (name_table_length);

    }

    else if (face_index == 0) /* Fail if first face doesn't have 'name' table. */

    {

      free (new_sfnt_data);

      hb_blob_destroy (blob);

      return NULL;

    }

  }

  /* The checkSumAdjustment field in the 'head' table is now wrong,

   * but that doesn't actually seem to cause any problems so we don't

   * bother. */

  hb_blob_destroy (blob);

  return hb_blob_create ((const char *) new_sfnt_data, new_length,

			 HB_MEMORY_MODE_WRITABLE, NULL, free);

}

hb_uniscribe_shaper_face_data_t *

_hb_uniscribe_shaper_face_data_create (hb_face_t *face)

{

  hb_uniscribe_shaper_face_data_t *data = (hb_uniscribe_shaper_face_data_t *) calloc (1, sizeof (hb_uniscribe_shaper_face_data_t));

  if (unlikely (!data))

    return NULL;

  data->funcs = hb_uniscribe_shaper_get_funcs ();

  if (unlikely (!data->funcs))

  {

    free (data);

    return NULL;

  }

  hb_blob_t *blob = hb_face_reference_blob (face);

  if (unlikely (!hb_blob_get_length (blob)))

    DEBUG_MSG (UNISCRIBE, face, "Face has empty blob");

  blob = _hb_rename_font (blob, data->face_name);

  if (unlikely (!blob))

  {

    free (data);

    return NULL;

  }

  DWORD num_fonts_installed;

  data->fh = AddFontMemResourceEx ((void *) hb_blob_get_data (blob, NULL),

				   hb_blob_get_length (blob),

				   0, &num_fonts_installed);

  if (unlikely (!data->fh))

  {

    DEBUG_MSG (UNISCRIBE, face, "Face AddFontMemResourceEx() failed");

    free (data);

    return NULL;

  }

  return data;

}

void

_hb_uniscribe_shaper_face_data_destroy (hb_uniscribe_shaper_face_data_t *data)

{

  RemoveFontMemResourceEx (data->fh);

  free (data);

}

/*

 * shaper font data

 */

struct hb_uniscribe_shaper_font_data_t {

  HDC hdc;

  LOGFONTW log_font;

  HFONT hfont;

  SCRIPT_CACHE script_cache;

  double x_mult, y_mult; /* From LOGFONT space to HB space. */

};

static bool

populate_log_font (LOGFONTW  *lf,

		   hb_font_t *font,

		   unsigned int font_size)

{

  memset (lf, 0, sizeof (*lf));

  lf->lfHeight = -font_size;

  lf->lfCharSet = DEFAULT_CHARSET;

  hb_face_t *face = font->face;

  hb_uniscribe_shaper_face_data_t *face_data = HB_SHAPER_DATA_GET (face);

  memcpy (lf->lfFaceName, face_data->face_name, sizeof (lf->lfFaceName));

  return true;

}

hb_uniscribe_shaper_font_data_t *

_hb_uniscribe_shaper_font_data_create (hb_font_t *font)

{

  if (unlikely (!hb_uniscribe_shaper_face_data_ensure (font->face))) return NULL;

  hb_uniscribe_shaper_font_data_t *data = (hb_uniscribe_shaper_font_data_t *) calloc (1, sizeof (hb_uniscribe_shaper_font_data_t));

  if (unlikely (!data))

    return NULL;

  int font_size = font->face->get_upem (); /* Default... */

  /* No idea if the following is even a good idea. */

  if (font->y_ppem)

    font_size = font->y_ppem;

  if (font_size < 0)

    font_size = -font_size;

  data->x_mult = (double) font->x_scale / font_size;

  data->y_mult = (double) font->y_scale / font_size;

  data->hdc = GetDC (NULL);

  if (unlikely (!populate_log_font (&data->log_font, font, font_size))) {

    DEBUG_MSG (UNISCRIBE, font, "Font populate_log_font() failed");

    _hb_uniscribe_shaper_font_data_destroy (data);

    return NULL;

  }

  data->hfont = CreateFontIndirectW (&data->log_font);

  if (unlikely (!data->hfont)) {

    DEBUG_MSG (UNISCRIBE, font, "Font CreateFontIndirectW() failed");

    _hb_uniscribe_shaper_font_data_destroy (data);

     return NULL;

  }

  if (!SelectObject (data->hdc, data->hfont)) {

    DEBUG_MSG (UNISCRIBE, font, "Font SelectObject() failed");

    _hb_uniscribe_shaper_font_data_destroy (data);

     return NULL;

  }

  return data;

}

void

_hb_uniscribe_shaper_font_data_destroy (hb_uniscribe_shaper_font_data_t *data)

{

  if (data->hdc)

    ReleaseDC (NULL, data->hdc);

  if (data->hfont)

    DeleteObject (data->hfont);

  if (data->script_cache)

    ScriptFreeCache (&data->script_cache);

  free (data);

}

LOGFONTW *

hb_uniscribe_font_get_logfontw (hb_font_t *font)

{

  if (unlikely (!hb_uniscribe_shaper_font_data_ensure (font))) return NULL;

  hb_uniscribe_shaper_font_data_t *font_data =  HB_SHAPER_DATA_GET (font);

  return &font_data->log_font;

}

HFONT

hb_uniscribe_font_get_hfont (hb_font_t *font)

{

  if (unlikely (!hb_uniscribe_shaper_font_data_ensure (font))) return NULL;

  hb_uniscribe_shaper_font_data_t *font_data =  HB_SHAPER_DATA_GET (font);

  return font_data->hfont;

}

/*

 * shaper shape_plan data

 */

struct hb_uniscribe_shaper_shape_plan_data_t {};

hb_uniscribe_shaper_shape_plan_data_t *

_hb_uniscribe_shaper_shape_plan_data_create (hb_shape_plan_t    *shape_plan HB_UNUSED,

					     const hb_feature_t *user_features HB_UNUSED,

					     unsigned int        num_user_features HB_UNUSED,

					     const int          *coords HB_UNUSED,

					     unsigned int        num_coords HB_UNUSED)

{

  return (hb_uniscribe_shaper_shape_plan_data_t *) HB_SHAPER_DATA_SUCCEEDED;

}

void

_hb_uniscribe_shaper_shape_plan_data_destroy (hb_uniscribe_shaper_shape_plan_data_t *data HB_UNUSED)

{

}

/*

 * shaper

 */

hb_bool_t

_hb_uniscribe_shape (hb_shape_plan_t    *shape_plan,

		     hb_font_t          *font,

		     hb_buffer_t        *buffer,

		     const hb_feature_t *features,

		     unsigned int        num_features)

{

  hb_face_t *face = font->face;

  hb_uniscribe_shaper_face_data_t *face_data = HB_SHAPER_DATA_GET (face);

  hb_uniscribe_shaper_font_data_t *font_data = HB_SHAPER_DATA_GET (font);

  hb_uniscribe_shaper_funcs_t *funcs = face_data->funcs;

  /*

   * Set up features.

   */

  hb_auto_array_t<OPENTYPE_FEATURE_RECORD> feature_records;

  hb_auto_array_t<range_record_t> range_records;

  if (num_features)

  {

    /* Sort features by start/end events. */

    hb_auto_array_t<feature_event_t> feature_events;

    for (unsigned int i = 0; i < num_features; i++)

    {

      active_feature_t feature;

      feature.rec.tagFeature = hb_uint32_swap (features[i].tag);

      feature.rec.lParameter = features[i].value;

      feature.order = i;

      feature_event_t *event;

      event = feature_events.push ();

      if (unlikely (!event))

	goto fail_features;

      event->index = features[i].start;

      event->start = true;

      event->feature = feature;

      event = feature_events.push ();

      if (unlikely (!event))

	goto fail_features;

      event->index = features[i].end;

      event->start = false;

      event->feature = feature;

    }

    feature_events.qsort ();

    /* Add a strategic final event. */

    {

      active_feature_t feature;

      feature.rec.tagFeature = 0;

      feature.rec.lParameter = 0;

      feature.order = num_features + 1;

      feature_event_t *event = feature_events.push ();

      if (unlikely (!event))

	goto fail_features;

      event->index = 0; /* This value does magic. */

      event->start = false;

      event->feature = feature;

    }

    /* Scan events and save features for each range. */

    hb_auto_array_t<active_feature_t> active_features;

    unsigned int last_index = 0;

    for (unsigned int i = 0; i < feature_events.len; i++)

    {

      feature_event_t *event = &feature_events[i];

      if (event->index != last_index)

      {

        /* Save a snapshot of active features and the range. */

	range_record_t *range = range_records.push ();

	if (unlikely (!range))

	  goto fail_features;

	unsigned int offset = feature_records.len;

	active_features.qsort ();

	for (unsigned int j = 0; j < active_features.len; j++)

	{

	  if (!j || active_features[j].rec.tagFeature != feature_records[feature_records.len - 1].tagFeature)

	  {

	    OPENTYPE_FEATURE_RECORD *feature = feature_records.push ();

	    if (unlikely (!feature))

	      goto fail_features;

	    *feature = active_features[j].rec;

	  }

	  else

	  {

	    /* Overrides value for existing feature. */

	    feature_records[feature_records.len - 1].lParameter = active_features[j].rec.lParameter;

	  }

	}

	/* Will convert to pointer after all is ready, since feature_records.array

	 * may move as we grow it. */

	range->props.potfRecords = reinterpret_cast<OPENTYPE_FEATURE_RECORD *> (offset);

	range->props.cotfRecords = feature_records.len - offset;

	range->index_first = last_index;

	range->index_last  = event->index - 1;

	last_index = event->index;

      }

      if (event->start) {

        active_feature_t *feature = active_features.push ();

	if (unlikely (!feature))

	  goto fail_features;

	*feature = event->feature;

      } else {

        active_feature_t *feature = active_features.find (&event->feature);

	if (feature)

	  active_features.remove (feature - active_features.array);

      }

    }

    if (!range_records.len) /* No active feature found. */

      goto fail_features;

    /* Fixup the pointers. */

    for (unsigned int i = 0; i < range_records.len; i++)

    {

      range_record_t *range = &range_records[i];

      range->props.potfRecords = feature_records.array + reinterpret_cast<uintptr_t> (range->props.potfRecords);

    }

  }

  else

  {

  fail_features:

    num_features = 0;

  }

#define FAIL(...) \

  HB_STMT_START { \

    DEBUG_MSG (UNISCRIBE, NULL, __VA_ARGS__); \

    return false; \

  } HB_STMT_END;

  HRESULT hr;

retry:

  unsigned int scratch_size;

  hb_buffer_t::scratch_buffer_t *scratch = buffer->get_scratch_buffer (&scratch_size);

#define ALLOCATE_ARRAY(Type, name, len) \

  Type *name = (Type *) scratch; \

  { \

    unsigned int _consumed = DIV_CEIL ((len) * sizeof (Type), sizeof (*scratch)); \

    assert (_consumed <= scratch_size); \

    scratch += _consumed; \

    scratch_size -= _consumed; \

  }

#define utf16_index() var1.u32

  ALLOCATE_ARRAY (WCHAR, pchars, buffer->len * 2);

  unsigned int chars_len = 0;

  for (unsigned int i = 0; i < buffer->len; i++)

  {

    hb_codepoint_t c = buffer->info[i].codepoint;

    buffer->info[i].utf16_index() = chars_len;

    if (likely (c <= 0xFFFFu))

      pchars[chars_len++] = c;

    else if (unlikely (c > 0x10FFFFu))

      pchars[chars_len++] = 0xFFFDu;

    else {

      pchars[chars_len++] = 0xD800u + ((c - 0x10000u) >> 10);

      pchars[chars_len++] = 0xDC00u + ((c - 0x10000u) & ((1u << 10) - 1));

    }

  }

  ALLOCATE_ARRAY (WORD, log_clusters, chars_len);

  ALLOCATE_ARRAY (SCRIPT_CHARPROP, char_props, chars_len);

  if (num_features)

  {

    /* Need log_clusters to assign features. */

    chars_len = 0;

    for (unsigned int i = 0; i < buffer->len; i++)

    {

      hb_codepoint_t c = buffer->info[i].codepoint;

      unsigned int cluster = buffer->info[i].cluster;

      log_clusters[chars_len++] = cluster;

      if (hb_in_range (c, 0x10000u, 0x10FFFFu))

	log_clusters[chars_len++] = cluster; /* Surrogates. */

    }

  }

  /* The -2 in the following is to compensate for possible

   * alignment needed after the WORD array.  sizeof(WORD) == 2. */

  unsigned int glyphs_size = (scratch_size * sizeof (int) - 2)

			   / (sizeof (WORD) +

			      sizeof (SCRIPT_GLYPHPROP) +

			      sizeof (int) +

			      sizeof (GOFFSET) +

			      sizeof (uint32_t));

  ALLOCATE_ARRAY (WORD, glyphs, glyphs_size);

  ALLOCATE_ARRAY (SCRIPT_GLYPHPROP, glyph_props, glyphs_size);

  ALLOCATE_ARRAY (int, advances, glyphs_size);

  ALLOCATE_ARRAY (GOFFSET, offsets, glyphs_size);

  ALLOCATE_ARRAY (uint32_t, vis_clusters, glyphs_size);

  /* Note:

   * We can't touch the contents of glyph_props.  Our fallback

   * implementations of Shape and Place functions use that buffer

   * by casting it to a different type.  It works because they

   * both agree about it, but if we want to access it here we

   * need address that issue first.

   */

#undef ALLOCATE_ARRAY

#define MAX_ITEMS 256

  SCRIPT_ITEM items[MAX_ITEMS + 1];

  SCRIPT_CONTROL bidi_control = {0};

  SCRIPT_STATE bidi_state = {0};

  ULONG script_tags[MAX_ITEMS];

  int item_count;

  /* MinGW32 doesn't define fMergeNeutralItems, so we bruteforce */

  //bidi_control.fMergeNeutralItems = true;

  *(uint32_t*)&bidi_control |= 1u<<24;

  bidi_state.uBidiLevel = HB_DIRECTION_IS_FORWARD (buffer->props.direction) ? 0 : 1;

  bidi_state.fOverrideDirection = 1;

  hr = funcs->ScriptItemizeOpenType (pchars,

				     chars_len,

				     MAX_ITEMS,

				     &bidi_control,

				     &bidi_state,

				     items,

				     script_tags,

				     &item_count);

  if (unlikely (FAILED (hr)))

    FAIL ("ScriptItemizeOpenType() failed: 0x%08xL", hr);

#undef MAX_ITEMS

  OPENTYPE_TAG language_tag = hb_uint32_swap (hb_ot_tag_from_language (buffer->props.language));

  hb_auto_array_t<TEXTRANGE_PROPERTIES*> range_properties;

  hb_auto_array_t<int> range_char_counts;

  unsigned int glyphs_offset = 0;

  unsigned int glyphs_len;

  bool backward = HB_DIRECTION_IS_BACKWARD (buffer->props.direction);

  for (unsigned int i = 0; i < item_count; i++)

  {

    unsigned int chars_offset = items[i].iCharPos;

    unsigned int item_chars_len = items[i + 1].iCharPos - chars_offset;

    if (num_features)

    {

      range_properties.shrink (0);

      range_char_counts.shrink (0);

      range_record_t *last_range = &range_records[0];

      for (unsigned int k = chars_offset; k < chars_offset + item_chars_len; k++)

      {

	range_record_t *range = last_range;

	while (log_clusters[k] < range->index_first)

	  range--;

	while (log_clusters[k] > range->index_last)

	  range++;

	if (!range_properties.len ||

	    &range->props != range_properties[range_properties.len - 1])

	{

	  TEXTRANGE_PROPERTIES **props = range_properties.push ();

	  int *c = range_char_counts.push ();