src/hb-old.cc - platform/external/harfbuzz_ng - Git at Google

 /*
  * Copyright © 2012  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
  */

 #include "hb-private.hh"

 #include "hb-old-private.hh"

 #include "hb-font-private.hh"
 #include "hb-buffer-private.hh"

 #include <harfbuzz.h>


 #ifndef HB_DEBUG_OLD
 #define HB_DEBUG_OLD (HB_DEBUG+0)
 #endif


 static HB_Script
 hb_old_script_from_script (hb_script_t script)
 {
   switch ((hb_tag_t) script)
   {
     default:
     case HB_SCRIPT_COMMON:		return HB_Script_Common;
     case HB_SCRIPT_GREEK:		return HB_Script_Greek;
     case HB_SCRIPT_CYRILLIC:		return HB_Script_Cyrillic;
     case HB_SCRIPT_ARMENIAN:		return HB_Script_Armenian;
     case HB_SCRIPT_HEBREW:		return HB_Script_Hebrew;
     case HB_SCRIPT_ARABIC:		return HB_Script_Arabic;
     case HB_SCRIPT_SYRIAC:		return HB_Script_Syriac;
     case HB_SCRIPT_THAANA:		return HB_Script_Thaana;
     case HB_SCRIPT_DEVANAGARI:		return HB_Script_Devanagari;
     case HB_SCRIPT_BENGALI:		return HB_Script_Bengali;
     case HB_SCRIPT_GURMUKHI:		return HB_Script_Gurmukhi;
     case HB_SCRIPT_GUJARATI:		return HB_Script_Gujarati;
     case HB_SCRIPT_ORIYA:		return HB_Script_Oriya;
     case HB_SCRIPT_TAMIL:		return HB_Script_Tamil;
     case HB_SCRIPT_TELUGU:		return HB_Script_Telugu;
     case HB_SCRIPT_KANNADA:		return HB_Script_Kannada;
     case HB_SCRIPT_MALAYALAM:		return HB_Script_Malayalam;
     case HB_SCRIPT_SINHALA:		return HB_Script_Sinhala;
     case HB_SCRIPT_THAI:		return HB_Script_Thai;
     case HB_SCRIPT_LAO:			return HB_Script_Lao;
     case HB_SCRIPT_TIBETAN:		return HB_Script_Tibetan;
     case HB_SCRIPT_MYANMAR:		return HB_Script_Myanmar;
     case HB_SCRIPT_GEORGIAN:		return HB_Script_Georgian;
     case HB_SCRIPT_HANGUL:		return HB_Script_Hangul;
     case HB_SCRIPT_OGHAM:		return HB_Script_Ogham;
     case HB_SCRIPT_RUNIC:		return HB_Script_Runic;
     case HB_SCRIPT_KHMER:		return HB_Script_Khmer;
     case HB_SCRIPT_NKO:			return HB_Script_Nko;
     case HB_SCRIPT_INHERITED:		return HB_Script_Inherited;
   }
 }


 static HB_Bool
 hb_old_convertStringToGlyphIndices (HB_Font old_font,
 				    const HB_UChar16 *string,
 				    hb_uint32 length,
 				    HB_Glyph *glyphs,
 				    hb_uint32 *numGlyphs,
 				    HB_Bool rightToLeft)
 {
   hb_font_t *font = (hb_font_t *) old_font->userData;

   for (unsigned int i = 0; i < length; i++)
   {
     hb_codepoint_t u;

     /* TODO Handle UTF-16.  Ugh */
     u = string[i];

     if (rightToLeft)
       u = hb_unicode_mirroring (hb_unicode_funcs_get_default (), u);

     hb_font_get_glyph (font, u, 0, &u); /* TODO Variation selectors */

     glyphs[i] = u;
   }
   *numGlyphs = length; // XXX

   return true;
 }

 static void
 hb_old_getGlyphAdvances (HB_Font old_font,
 			 const HB_Glyph *glyphs,
 			 hb_uint32 numGlyphs,
 			 HB_Fixed *advances,
 			 int flags /*HB_ShaperFlag*/)
 {
   hb_font_t *font = (hb_font_t *) old_font->userData;

   for (unsigned int i = 0; i < numGlyphs; i++)
     advances[i] = hb_font_get_glyph_h_advance (font, glyphs[i]);
 }

 static HB_Bool
 hb_old_canRender (HB_Font old_font,
 		  const HB_UChar16 *string,
 		  hb_uint32 length)
 {
   return true; // TODO
 }

 static HB_Error
 hb_old_getPointInOutline (HB_Font old_font,
 			  HB_Glyph glyph,
 			  int flags /*HB_ShaperFlag*/,
 			  hb_uint32 point,
 			  HB_Fixed *xpos,
 			  HB_Fixed *ypos,
 			  hb_uint32 *nPoints)
 {
   return HB_Err_Ok; // TODO
 }

 static void
 hb_old_getGlyphMetrics (HB_Font old_font,
 			HB_Glyph glyph,
 			HB_GlyphMetrics *metrics)
 {
   // TODO
 }

 static HB_Fixed
 hb_old_getFontMetric (HB_Font old_font,
 		      HB_FontMetric metric)
 {
   return 0; // TODO
 }

 static const HB_FontClass hb_old_font_class = {
   hb_old_convertStringToGlyphIndices,
   hb_old_getGlyphAdvances,
   hb_old_canRender,
   hb_old_getPointInOutline,
   hb_old_getGlyphMetrics,
   hb_old_getFontMetric
 };


 static hb_user_data_key_t hb_old_data_key;

 static HB_Error
 table_func (void *font, HB_Tag tag, HB_Byte *buffer, HB_UInt *length)
 {
   hb_face_t *face = (hb_face_t *) font;
   hb_blob_t *blob = hb_face_reference_table (face, (hb_tag_t) tag);
   unsigned int capacity = *length;
   *length = hb_blob_get_length (blob);
   memcpy (buffer, hb_blob_get_data (blob, NULL), MIN (capacity, *length));
   hb_blob_destroy (blob);
  return HB_Err_Ok;
 }

 static HB_Face
 _hb_old_face_get (hb_face_t *face)
 {
   HB_Face data = (HB_Face) hb_face_get_user_data (face, &hb_old_data_key);
   if (likely (data)) return data;

   data = HB_NewFace (face, table_func);

   if (unlikely (!data)) {
     DEBUG_MSG (OLD, face, "HB_NewFace failed");
     return NULL;
   }

   if (unlikely (!hb_face_set_user_data (face, &hb_old_data_key, data,
                                         (hb_destroy_func_t) HB_FreeFace,
                                         false)))
   {
     HB_FreeFace (data);
     data = (HB_Face) hb_face_get_user_data (face, &hb_old_data_key);
     if (data)
       return data;
     else
       return NULL;
   }

   return data;
 }


 static HB_Font
 _hb_old_font_get (hb_font_t *font)
 {
   HB_Font data = (HB_Font) calloc (1, sizeof (HB_FontRec));
   if (unlikely (!data)) {
     DEBUG_MSG (OLD, font, "malloc()ing HB_Font failed");
     return NULL;
   }

   data->klass = &hb_old_font_class;
   data->x_ppem = font->x_ppem;
   data->y_ppem = font->y_ppem;
   data->x_scale = font->x_scale; // XXX
   data->y_scale = font->y_scale; // XXX
   data->userData = font;

   if (unlikely (!hb_font_set_user_data (font, &hb_old_data_key, data,
                                         (hb_destroy_func_t) free,
                                         false)))
   {
     free (data);
     data = (HB_Font) hb_font_get_user_data (font, &hb_old_data_key);
     if (data)
       return data;
     else
       return NULL;
   }

   return data;
 }

 hb_bool_t
 _hb_old_shape (hb_font_t          *font,
 	       hb_buffer_t        *buffer,
 	       const hb_feature_t *features,
 	       unsigned int        num_features)
 {
   if (unlikely (!buffer->len))
     return true;

   buffer->guess_properties ();

 #define FAIL(...) \
   HB_STMT_START { \
     DEBUG_MSG (OLD, NULL, __VA_ARGS__); \
     return false; \
   } HB_STMT_END;

   HB_Face old_face = _hb_old_face_get (font->face);
   if (unlikely (!old_face))
     FAIL ("Couldn't get old face");

   HB_Font old_font = _hb_old_font_get (font);
   if (unlikely (!old_font))
     FAIL ("Couldn't get old font");

 retry:

   unsigned int scratch_size;
   char *scratch = (char *) buffer->get_scratch_buffer (&scratch_size);

 #define utf16_index() var1.u32
   HB_UChar16 *pchars = (HB_UChar16 *) scratch;
   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 < 0x10000))
       pchars[chars_len++] = c;
     else if (unlikely (c >= 0x110000))
       pchars[chars_len++] = 0xFFFD;
     else {
       pchars[chars_len++] = 0xD800 + ((c - 0x10000) >> 10);
       pchars[chars_len++] = 0xDC00 + ((c - 0x10000) & ((1 << 10) - 1));
     }
   }
 #undef utf16_index


 #define ALLOCATE_ARRAY(Type, name, len) \
   name = (Type *) scratch; \
   scratch += len * sizeof (name[0]); \
   scratch_size -= len * sizeof (name[0]);


   HB_ShaperItem item = {0};

   ALLOCATE_ARRAY (const HB_UChar16, item.string, chars_len);
   item.stringLength = chars_len;
   item.item.pos = 0;
   item.item.length = item.stringLength;
   item.item.script = hb_old_script_from_script (buffer->props.script);
   item.item.bidiLevel = HB_DIRECTION_IS_FORWARD (buffer->props.direction) ? 0 : 1;

   item.font = old_font;
   item.face = old_face;
   item.shaperFlags = 0;

   item.glyphIndicesPresent = false;

   /* TODO Alignment. */
   unsigned int num_glyphs = scratch_size / (sizeof (HB_Glyph) +
 					    sizeof (HB_GlyphAttributes) +
 					    sizeof (HB_Fixed) +
 					    sizeof (HB_FixedPoint) +
 					    sizeof (unsigned short));

   item.num_glyphs = num_glyphs;
   ALLOCATE_ARRAY (HB_Glyph, item.glyphs, num_glyphs);
   ALLOCATE_ARRAY (HB_GlyphAttributes, item.attributes, num_glyphs);
   ALLOCATE_ARRAY (HB_Fixed, item.advances, num_glyphs);
   ALLOCATE_ARRAY (HB_FixedPoint, item.offsets, num_glyphs);
   ALLOCATE_ARRAY (unsigned short, item.log_clusters, num_glyphs);

   if (!HB_ShapeItem (&item))
     return false;

   if (unlikely (item.num_glyphs > num_glyphs))
   {
     buffer->ensure (buffer->allocated * 2);
     if (buffer->in_error)
       FAIL ("Buffer resize failed");
     goto retry;
   }
   num_glyphs = item.num_glyphs;

 #undef ALLOCATE_ARRAY

   hb_glyph_info_t *info = buffer->info;
   for (unsigned int i = 0; i < num_glyphs; i++)
   {
     info[i].codepoint = item.glyphs[i];
     info[i].cluster = item.log_clusters[i];

     info[i].mask = item.advances[i];
     info[i].var1.u32 = item.offsets[i].x;
     info[i].var2.u32 = item.offsets[i].y;
   }
   buffer->len = num_glyphs;

   buffer->clear_positions ();

   unsigned int count = buffer->len;
   for (unsigned int i = 0; i < count; ++i) {
     hb_glyph_info_t *info = &buffer->info[i];
     hb_glyph_position_t *pos = &buffer->pos[i];

     /* TODO vertical */
     pos->x_advance = info->mask;
     pos->x_offset = info->var1.u32;
     pos->y_offset = info->var2.u32;
   }

   if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
     buffer->reverse ();

   return true;
 }
	/*
	* Copyright © 2012 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
	*/

	#include "hb-private.hh"

	#include "hb-old-private.hh"

	#include "hb-font-private.hh"
	#include "hb-buffer-private.hh"

	#include <harfbuzz.h>


	#ifndef HB_DEBUG_OLD
	#define HB_DEBUG_OLD (HB_DEBUG+0)
	#endif


	static HB_Script
	hb_old_script_from_script (hb_script_t script)
	{
	switch ((hb_tag_t) script)
	{
	default:
	case HB_SCRIPT_COMMON: return HB_Script_Common;
	case HB_SCRIPT_GREEK: return HB_Script_Greek;
	case HB_SCRIPT_CYRILLIC: return HB_Script_Cyrillic;
	case HB_SCRIPT_ARMENIAN: return HB_Script_Armenian;
	case HB_SCRIPT_HEBREW: return HB_Script_Hebrew;
	case HB_SCRIPT_ARABIC: return HB_Script_Arabic;
	case HB_SCRIPT_SYRIAC: return HB_Script_Syriac;
	case HB_SCRIPT_THAANA: return HB_Script_Thaana;
	case HB_SCRIPT_DEVANAGARI: return HB_Script_Devanagari;
	case HB_SCRIPT_BENGALI: return HB_Script_Bengali;
	case HB_SCRIPT_GURMUKHI: return HB_Script_Gurmukhi;
	case HB_SCRIPT_GUJARATI: return HB_Script_Gujarati;
	case HB_SCRIPT_ORIYA: return HB_Script_Oriya;
	case HB_SCRIPT_TAMIL: return HB_Script_Tamil;
	case HB_SCRIPT_TELUGU: return HB_Script_Telugu;
	case HB_SCRIPT_KANNADA: return HB_Script_Kannada;
	case HB_SCRIPT_MALAYALAM: return HB_Script_Malayalam;
	case HB_SCRIPT_SINHALA: return HB_Script_Sinhala;
	case HB_SCRIPT_THAI: return HB_Script_Thai;
	case HB_SCRIPT_LAO: return HB_Script_Lao;
	case HB_SCRIPT_TIBETAN: return HB_Script_Tibetan;
	case HB_SCRIPT_MYANMAR: return HB_Script_Myanmar;
	case HB_SCRIPT_GEORGIAN: return HB_Script_Georgian;
	case HB_SCRIPT_HANGUL: return HB_Script_Hangul;
	case HB_SCRIPT_OGHAM: return HB_Script_Ogham;
	case HB_SCRIPT_RUNIC: return HB_Script_Runic;
	case HB_SCRIPT_KHMER: return HB_Script_Khmer;
	case HB_SCRIPT_NKO: return HB_Script_Nko;
	case HB_SCRIPT_INHERITED: return HB_Script_Inherited;
	}
	}


	static HB_Bool
	hb_old_convertStringToGlyphIndices (HB_Font old_font,
	const HB_UChar16 *string,
	hb_uint32 length,
	HB_Glyph *glyphs,
	hb_uint32 *numGlyphs,
	HB_Bool rightToLeft)
	{
	hb_font_t font = (hb_font_t ) old_font->userData;

	for (unsigned int i = 0; i < length; i++)
	{
	hb_codepoint_t u;

	/* TODO Handle UTF-16. Ugh */
	u = string[i];

	if (rightToLeft)
	u = hb_unicode_mirroring (hb_unicode_funcs_get_default (), u);

	hb_font_get_glyph (font, u, 0, &u); /* TODO Variation selectors */

	glyphs[i] = u;
	}
	*numGlyphs = length; // XXX

	return true;
	}

	static void
	hb_old_getGlyphAdvances (HB_Font old_font,
	const HB_Glyph *glyphs,
	hb_uint32 numGlyphs,
	HB_Fixed *advances,
	int flags /HB_ShaperFlag/)
	{
	hb_font_t font = (hb_font_t ) old_font->userData;

	for (unsigned int i = 0; i < numGlyphs; i++)
	advances[i] = hb_font_get_glyph_h_advance (font, glyphs[i]);
	}

	static HB_Bool
	hb_old_canRender (HB_Font old_font,
	const HB_UChar16 *string,
	hb_uint32 length)
	{
	return true; // TODO
	}

	static HB_Error
	hb_old_getPointInOutline (HB_Font old_font,
	HB_Glyph glyph,
	int flags /HB_ShaperFlag/,
	hb_uint32 point,
	HB_Fixed *xpos,
	HB_Fixed *ypos,
	hb_uint32 *nPoints)
	{
	return HB_Err_Ok; // TODO
	}

	static void
	hb_old_getGlyphMetrics (HB_Font old_font,
	HB_Glyph glyph,
	HB_GlyphMetrics *metrics)
	{
	// TODO
	}

	static HB_Fixed
	hb_old_getFontMetric (HB_Font old_font,
	HB_FontMetric metric)
	{
	return 0; // TODO
	}

	static const HB_FontClass hb_old_font_class = {
	hb_old_convertStringToGlyphIndices,
	hb_old_getGlyphAdvances,
	hb_old_canRender,
	hb_old_getPointInOutline,
	hb_old_getGlyphMetrics,
	hb_old_getFontMetric
	};



	static hb_user_data_key_t hb_old_data_key;

	static HB_Error
	table_func (void font, HB_Tag tag, HB_Byte buffer, HB_UInt *length)
	{
	hb_face_t face = (hb_face_t ) font;
	hb_blob_t *blob = hb_face_reference_table (face, (hb_tag_t) tag);
	unsigned int capacity = *length;
	*length = hb_blob_get_length (blob);
	memcpy (buffer, hb_blob_get_data (blob, NULL), MIN (capacity, *length));
	hb_blob_destroy (blob);
	return HB_Err_Ok;
	}

	static HB_Face
	_hb_old_face_get (hb_face_t *face)
	{
	HB_Face data = (HB_Face) hb_face_get_user_data (face, &hb_old_data_key);
	if (likely (data)) return data;

	data = HB_NewFace (face, table_func);

	if (unlikely (!data)) {
	DEBUG_MSG (OLD, face, "HB_NewFace failed");
	return NULL;
	}

	if (unlikely (!hb_face_set_user_data (face, &hb_old_data_key, data,
	(hb_destroy_func_t) HB_FreeFace,
	false)))
	{
	HB_FreeFace (data);
	data = (HB_Face) hb_face_get_user_data (face, &hb_old_data_key);
	if (data)
	return data;
	else
	return NULL;
	}

	return data;
	}


	static HB_Font
	_hb_old_font_get (hb_font_t *font)
	{
	HB_Font data = (HB_Font) calloc (1, sizeof (HB_FontRec));
	if (unlikely (!data)) {
	DEBUG_MSG (OLD, font, "malloc()ing HB_Font failed");
	return NULL;
	}

	data->klass = &hb_old_font_class;
	data->x_ppem = font->x_ppem;
	data->y_ppem = font->y_ppem;
	data->x_scale = font->x_scale; // XXX
	data->y_scale = font->y_scale; // XXX
	data->userData = font;

	if (unlikely (!hb_font_set_user_data (font, &hb_old_data_key, data,
	(hb_destroy_func_t) free,
	false)))
	{
	free (data);
	data = (HB_Font) hb_font_get_user_data (font, &hb_old_data_key);
	if (data)
	return data;
	else
	return NULL;
	}

	return data;
	}

	hb_bool_t
	_hb_old_shape (hb_font_t *font,
	hb_buffer_t *buffer,
	const hb_feature_t *features,
	unsigned int num_features)
	{
	if (unlikely (!buffer->len))
	return true;

	buffer->guess_properties ();

	#define FAIL(...) \
	HB_STMT_START { \
	DEBUG_MSG (OLD, NULL, __VA_ARGS__); \
	return false; \
	} HB_STMT_END;

	HB_Face old_face = _hb_old_face_get (font->face);
	if (unlikely (!old_face))
	FAIL ("Couldn't get old face");

	HB_Font old_font = _hb_old_font_get (font);
	if (unlikely (!old_font))
	FAIL ("Couldn't get old font");

	retry:

	unsigned int scratch_size;
	char scratch = (char ) buffer->get_scratch_buffer (&scratch_size);

	#define utf16_index() var1.u32
	HB_UChar16 pchars = (HB_UChar16 ) scratch;
	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 < 0x10000))
	pchars[chars_len++] = c;
	else if (unlikely (c >= 0x110000))
	pchars[chars_len++] = 0xFFFD;
	else {
	pchars[chars_len++] = 0xD800 + ((c - 0x10000) >> 10);
	pchars[chars_len++] = 0xDC00 + ((c - 0x10000) & ((1 << 10) - 1));
	}
	}
	#undef utf16_index


	#define ALLOCATE_ARRAY(Type, name, len) \
	name = (Type *) scratch; \
	scratch += len * sizeof (name[0]); \
	scratch_size -= len * sizeof (name[0]);


	HB_ShaperItem item = {0};

	ALLOCATE_ARRAY (const HB_UChar16, item.string, chars_len);
	item.stringLength = chars_len;
	item.item.pos = 0;
	item.item.length = item.stringLength;
	item.item.script = hb_old_script_from_script (buffer->props.script);
	item.item.bidiLevel = HB_DIRECTION_IS_FORWARD (buffer->props.direction) ? 0 : 1;

	item.font = old_font;
	item.face = old_face;
	item.shaperFlags = 0;

	item.glyphIndicesPresent = false;

	/* TODO Alignment. */
	unsigned int num_glyphs = scratch_size / (sizeof (HB_Glyph) +
	sizeof (HB_GlyphAttributes) +
	sizeof (HB_Fixed) +
	sizeof (HB_FixedPoint) +
	sizeof (unsigned short));

	item.num_glyphs = num_glyphs;
	ALLOCATE_ARRAY (HB_Glyph, item.glyphs, num_glyphs);
	ALLOCATE_ARRAY (HB_GlyphAttributes, item.attributes, num_glyphs);
	ALLOCATE_ARRAY (HB_Fixed, item.advances, num_glyphs);
	ALLOCATE_ARRAY (HB_FixedPoint, item.offsets, num_glyphs);
	ALLOCATE_ARRAY (unsigned short, item.log_clusters, num_glyphs);

	if (!HB_ShapeItem (&item))
	return false;

	if (unlikely (item.num_glyphs > num_glyphs))
	{
	buffer->ensure (buffer->allocated * 2);
	if (buffer->in_error)
	FAIL ("Buffer resize failed");
	goto retry;
	}
	num_glyphs = item.num_glyphs;

	#undef ALLOCATE_ARRAY

	hb_glyph_info_t *info = buffer->info;
	for (unsigned int i = 0; i < num_glyphs; i++)
	{
	info[i].codepoint = item.glyphs[i];
	info[i].cluster = item.log_clusters[i];

	info[i].mask = item.advances[i];
	info[i].var1.u32 = item.offsets[i].x;
	info[i].var2.u32 = item.offsets[i].y;
	}
	buffer->len = num_glyphs;

	buffer->clear_positions ();

	unsigned int count = buffer->len;
	for (unsigned int i = 0; i < count; ++i) {
	hb_glyph_info_t *info = &buffer->info[i];
	hb_glyph_position_t *pos = &buffer->pos[i];

	/* TODO vertical */
	pos->x_advance = info->mask;
	pos->x_offset = info->var1.u32;
	pos->y_offset = info->var2.u32;
	}

	if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
	buffer->reverse ();

	return true;
	}