text: /*
   * 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 ();
  	  if (unlikely (!props || !c))
  	  {
  	    range_properties.shrink (0);
  	    range_char_counts.shrink (0);
  	    break;
  	  }
  	  *props = &range->props;
  	  *c = 1;
  	}
  	else
  	{
  	  range_char_counts[range_char_counts.len - 1]++;
  	}
  
  	last_range = range;
        }
      }
  
      /* Asking for glyphs in logical order circumvents at least
       * one bug in Uniscribe. */
      items[i].a.fLogicalOrder = true;
  
    retry_shape:
      hr = funcs->ScriptShapeOpenType (font_data->hdc,
  				     &font_data->script_cache,
  				     &items[i].a,
  				     script_tags[i],
  				     language_tag,
  				     range_char_counts.array,
  				     range_properties.array,
  				     range_properties.len,
  				     pchars + chars_offset,
  				     item_chars_len,
  				     glyphs_size - glyphs_offset,
  				     /* out */
  				     log_clusters + chars_offset,
  				     char_props + chars_offset,
  				     glyphs + glyphs_offset,
  				     glyph_props + glyphs_offset,
  				     (int *) &glyphs_len);
  
      if (unlikely (items[i].a.fNoGlyphIndex))
        FAIL ("ScriptShapeOpenType() set fNoGlyphIndex");
      if (unlikely (hr == E_OUTOFMEMORY || hr == E_NOT_SUFFICIENT_BUFFER))
      {
        if (unlikely (!buffer->ensure (buffer->allocated * 2)))
  	FAIL ("Buffer resize failed");
        goto retry;
      }
      if (unlikely (hr == USP_E_SCRIPT_NOT_IN_FONT))
      {
        if (items[i].a.eScript == SCRIPT_UNDEFINED)
  	FAIL ("ScriptShapeOpenType() failed: Font doesn't support script");
        items[i].a.eScript = SCRIPT_UNDEFINED;
        goto retry_shape;
      }
      if (unlikely (FAILED (hr)))
      {
        FAIL ("ScriptShapeOpenType() failed: 0x%08xL", hr);
      }
  
      for (unsigned int j = chars_offset; j < chars_offset + item_chars_len; j++)
        log_clusters[j] += glyphs_offset;
  
      hr = funcs->ScriptPlaceOpenType (font_data->hdc,
  				     &font_data->script_cache,
  				     &items[i].a,
  				     script_tags[i],
  				     language_tag,
  				     range_char_counts.array,
  				     range_properties.array,
  				     range_properties.len,
  				     pchars + chars_offset,
  				     log_clusters + chars_offset,
  				     char_props + chars_offset,
  				     item_chars_len,
  				     glyphs + glyphs_offset,
  				     glyph_props + glyphs_offset,
  				     glyphs_len,
  				     /* out */
  				     advances + glyphs_offset,
  				     offsets + glyphs_offset,
  				     NULL);
      if (unlikely (FAILED (hr)))
        FAIL ("ScriptPlaceOpenType() failed: 0x%08xL", hr);
  
      if (DEBUG_ENABLED (UNISCRIBE))
        fprintf (stderr, "Item %d RTL %d LayoutRTL %d LogicalOrder %d ScriptTag %c%c%c%c\n",
  	       i,
  	       items[i].a.fRTL,
  	       items[i].a.fLayoutRTL,
  	       items[i].a.fLogicalOrder,
  	       HB_UNTAG (hb_uint32_swap (script_tags[i])));
  
      glyphs_offset += glyphs_len;
    }
    glyphs_len = glyphs_offset;
  
    /* Ok, we've got everything we need, now compose output buffer,
     * very, *very*, carefully! */
  
    /* Calculate visual-clusters.  That's what we ship. */
    for (unsigned int i = 0; i < glyphs_len; i++)
      vis_clusters[i] = -1;
    for (unsigned int i = 0; i < buffer->len; i++) {
      uint32_t *p = &vis_clusters[log_clusters[buffer->info[i].utf16_index()]];
      *p = MIN (*p, buffer->info[i].cluster);
    }
    for (unsigned int i = 1; i < glyphs_len; i++)
      if (vis_clusters[i] == -1)
        vis_clusters[i] = vis_clusters[i - 1];
  
  #undef utf16_index
  
    if (unlikely (!buffer->ensure (glyphs_len)))
      FAIL ("Buffer in error");
  
  #undef FAIL
  
    /* Set glyph infos */
    buffer->len = 0;
    for (unsigned int i = 0; i < glyphs_len; i++)
    {
      hb_glyph_info_t *info = &buffer->info[buffer->len++];
  
      info->codepoint = glyphs[i];
      info->cluster = vis_clusters[i];
  
      /* The rest is crap.  Let's store position info there for now. */
      info->mask = advances[i];
      info->var1.i32 = offsets[i].du;
      info->var2.i32 = offsets[i].dv;
    }
  
    /* Set glyph positions */
    buffer->clear_positions ();
    double x_mult = font_data->x_mult, y_mult = font_data->y_mult;
    for (unsigned int i = 0; i < glyphs_len; i++)
    {
      hb_glyph_info_t *info = &buffer->info[i];
      hb_glyph_position_t *pos = &buffer->pos[i];
  
      /* TODO vertical */
      pos->x_advance = x_mult * (int32_t) info->mask;
      pos->x_offset = x_mult * (backward ? -info->var1.i32 : info->var1.i32);
      pos->y_offset = y_mult * info->var2.i32;
  
      info->mask = HB_GLYPH_FLAG_UNSAFE_TO_BREAK;
    }
  
    if (backward)
      hb_buffer_reverse (buffer);
  
    /* Wow, done! */
    return true;
  }
  
  
  