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

 /*
  * Copyright © 2009  Red Hat, Inc.
  * Copyright © 2011  Codethink Limited
  * Copyright © 2010,2011,2012  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.
  *
  * Red Hat Author(s): Behdad Esfahbod
  * Codethink Author(s): Ryan Lortie
  * Google Author(s): Behdad Esfahbod
  */

 #include "hb-private.hh"

 #include "hb-unicode-private.hh"


 /*
  * hb_unicode_funcs_t
  */

 static hb_unicode_combining_class_t
 hb_unicode_combining_class_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
 				hb_codepoint_t      unicode   HB_UNUSED,
 				void               *user_data HB_UNUSED)
 {
   return HB_UNICODE_COMBINING_CLASS_NOT_REORDERED;
 }

 static unsigned int
 hb_unicode_eastasian_width_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
 				hb_codepoint_t      unicode   HB_UNUSED,
 				void               *user_data HB_UNUSED)
 {
   return 1;
 }

 static hb_unicode_general_category_t
 hb_unicode_general_category_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
 				 hb_codepoint_t      unicode   HB_UNUSED,
 				 void               *user_data HB_UNUSED)
 {
   return HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER;
 }

 static hb_codepoint_t
 hb_unicode_mirroring_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
 			  hb_codepoint_t      unicode   HB_UNUSED,
 			  void               *user_data HB_UNUSED)
 {
   return unicode;
 }

 static hb_script_t
 hb_unicode_script_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
 		       hb_codepoint_t      unicode   HB_UNUSED,
 		       void               *user_data HB_UNUSED)
 {
   return HB_SCRIPT_UNKNOWN;
 }

 static hb_bool_t
 hb_unicode_compose_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
 			hb_codepoint_t      a         HB_UNUSED,
 			hb_codepoint_t      b         HB_UNUSED,
 			hb_codepoint_t     *ab        HB_UNUSED,
 			void               *user_data HB_UNUSED)
 {
   return false;
 }

 static hb_bool_t
 hb_unicode_decompose_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
 			  hb_codepoint_t      ab        HB_UNUSED,
 			  hb_codepoint_t     *a         HB_UNUSED,
 			  hb_codepoint_t     *b         HB_UNUSED,
 			  void               *user_data HB_UNUSED)
 {
   return false;
 }


 static unsigned int
 hb_unicode_decompose_compatibility_nil (hb_unicode_funcs_t *ufuncs     HB_UNUSED,
 					hb_codepoint_t      u          HB_UNUSED,
 					hb_codepoint_t     *decomposed HB_UNUSED,
 					void               *user_data  HB_UNUSED)
 {
   return 0;
 }


 #define HB_UNICODE_FUNCS_IMPLEMENT_SET \
   HB_UNICODE_FUNCS_IMPLEMENT (glib) \
   HB_UNICODE_FUNCS_IMPLEMENT (icu) \
   HB_UNICODE_FUNCS_IMPLEMENT (ucdn) \
   HB_UNICODE_FUNCS_IMPLEMENT (nil) \
   /* ^--- Add new callbacks before nil */

 #define hb_nil_get_unicode_funcs hb_unicode_funcs_get_empty

 /* Prototype them all */
 #define HB_UNICODE_FUNCS_IMPLEMENT(set) \
 extern "C" hb_unicode_funcs_t *hb_##set##_get_unicode_funcs (void);
 HB_UNICODE_FUNCS_IMPLEMENT_SET
 #undef HB_UNICODE_FUNCS_IMPLEMENT


 hb_unicode_funcs_t *
 hb_unicode_funcs_get_default (void)
 {
 #define HB_UNICODE_FUNCS_IMPLEMENT(set) \
   return hb_##set##_get_unicode_funcs ();

 #ifdef HAVE_GLIB
   HB_UNICODE_FUNCS_IMPLEMENT(glib)
 #elif defined(HAVE_ICU)
   HB_UNICODE_FUNCS_IMPLEMENT(icu)
 #elif defined(HAVE_UCDN)
   HB_UNICODE_FUNCS_IMPLEMENT(ucdn)
 #else
 #define HB_UNICODE_FUNCS_NIL 1
   HB_UNICODE_FUNCS_IMPLEMENT(nil)
 #endif

 #undef HB_UNICODE_FUNCS_IMPLEMENT
 }

 #if !defined(HB_NO_UNICODE_FUNCS) && defined(HB_UNICODE_FUNCS_NIL)
 #pragma message("Could not find any Unicode functions implementation, you have to provide your own.")
 #pragma message("To suppress this warnings, define HB_NO_UNICODE_FUNCS.")
 #endif

 hb_unicode_funcs_t *
 hb_unicode_funcs_create (hb_unicode_funcs_t *parent)
 {
   hb_unicode_funcs_t *ufuncs;

   if (!(ufuncs = hb_object_create<hb_unicode_funcs_t> ()))
     return hb_unicode_funcs_get_empty ();

   if (!parent)
     parent = hb_unicode_funcs_get_empty ();

   hb_unicode_funcs_make_immutable (parent);
   ufuncs->parent = hb_unicode_funcs_reference (parent);

   ufuncs->func = parent->func;

   /* We can safely copy user_data from parent since we hold a reference
    * onto it and it's immutable.  We should not copy the destroy notifiers
    * though. */
   ufuncs->user_data = parent->user_data;

   return ufuncs;
 }


 const hb_unicode_funcs_t _hb_unicode_funcs_nil = {
   HB_OBJECT_HEADER_STATIC,

   NULL, /* parent */
   true, /* immutable */
   {
 #define HB_UNICODE_FUNC_IMPLEMENT(name) hb_unicode_##name##_nil,
     HB_UNICODE_FUNCS_IMPLEMENT_CALLBACKS
 #undef HB_UNICODE_FUNC_IMPLEMENT
   }
 };

 hb_unicode_funcs_t *
 hb_unicode_funcs_get_empty (void)
 {
   return const_cast<hb_unicode_funcs_t *> (&_hb_unicode_funcs_nil);
 }

 hb_unicode_funcs_t *
 hb_unicode_funcs_reference (hb_unicode_funcs_t *ufuncs)
 {
   return hb_object_reference (ufuncs);
 }

 void
 hb_unicode_funcs_destroy (hb_unicode_funcs_t *ufuncs)
 {
   if (!hb_object_destroy (ufuncs)) return;

 #define HB_UNICODE_FUNC_IMPLEMENT(name) \
   if (ufuncs->destroy.name) ufuncs->destroy.name (ufuncs->user_data.name);
     HB_UNICODE_FUNCS_IMPLEMENT_CALLBACKS
 #undef HB_UNICODE_FUNC_IMPLEMENT

   hb_unicode_funcs_destroy (ufuncs->parent);

   free (ufuncs);
 }

 hb_bool_t
 hb_unicode_funcs_set_user_data (hb_unicode_funcs_t *ufuncs,
 			        hb_user_data_key_t *key,
 			        void *              data,
 			        hb_destroy_func_t   destroy,
 				hb_bool_t           replace)
 {
   return hb_object_set_user_data (ufuncs, key, data, destroy, replace);
 }

 void *
 hb_unicode_funcs_get_user_data (hb_unicode_funcs_t *ufuncs,
 			        hb_user_data_key_t *key)
 {
   return hb_object_get_user_data (ufuncs, key);
 }


 void
 hb_unicode_funcs_make_immutable (hb_unicode_funcs_t *ufuncs)
 {
   if (hb_object_is_inert (ufuncs))
     return;

   ufuncs->immutable = true;
 }

 hb_bool_t
 hb_unicode_funcs_is_immutable (hb_unicode_funcs_t *ufuncs)
 {
   return ufuncs->immutable;
 }

 hb_unicode_funcs_t *
 hb_unicode_funcs_get_parent (hb_unicode_funcs_t *ufuncs)
 {
   return ufuncs->parent ? ufuncs->parent : hb_unicode_funcs_get_empty ();
 }


 #define HB_UNICODE_FUNC_IMPLEMENT(name)						\
 										\
 void										\
 hb_unicode_funcs_set_##name##_func (hb_unicode_funcs_t		   *ufuncs,	\
 				    hb_unicode_##name##_func_t	    func,	\
 				    void			   *user_data,	\
 				    hb_destroy_func_t		    destroy)	\
 {										\
   if (ufuncs->immutable)							\
     return;									\
 										\
   if (ufuncs->destroy.name)							\
     ufuncs->destroy.name (ufuncs->user_data.name);				\
 										\
   if (func) {									\
     ufuncs->func.name = func;							\
     ufuncs->user_data.name = user_data;						\
     ufuncs->destroy.name = destroy;						\
   } else {									\
     ufuncs->func.name = ufuncs->parent->func.name;				\
     ufuncs->user_data.name = ufuncs->parent->user_data.name;			\
     ufuncs->destroy.name = NULL;						\
   }										\
 }

 HB_UNICODE_FUNCS_IMPLEMENT_CALLBACKS
 #undef HB_UNICODE_FUNC_IMPLEMENT


 #define HB_UNICODE_FUNC_IMPLEMENT(return_type, name)				\
 										\
 return_type									\
 hb_unicode_##name (hb_unicode_funcs_t *ufuncs,					\
 		   hb_codepoint_t      unicode)					\
 {										\
   return ufuncs->name (unicode);						\
 }
 HB_UNICODE_FUNCS_IMPLEMENT_CALLBACKS_SIMPLE
 #undef HB_UNICODE_FUNC_IMPLEMENT

 hb_bool_t
 hb_unicode_compose (hb_unicode_funcs_t *ufuncs,
 		    hb_codepoint_t      a,
 		    hb_codepoint_t      b,
 		    hb_codepoint_t     *ab)
 {
   return ufuncs->compose (a, b, ab);
 }

 hb_bool_t
 hb_unicode_decompose (hb_unicode_funcs_t *ufuncs,
 		      hb_codepoint_t      ab,
 		      hb_codepoint_t     *a,
 		      hb_codepoint_t     *b)
 {
   return ufuncs->decompose (ab, a, b);
 }

 unsigned int
 hb_unicode_decompose_compatibility (hb_unicode_funcs_t *ufuncs,
 				    hb_codepoint_t      u,
 				    hb_codepoint_t     *decomposed)
 {
   return ufuncs->decompose_compatibility (u, decomposed);
 }


 /* See hb-unicode-private.hh for details. */
 const uint8_t
 _hb_modified_combining_class[256] =
 {
   0, /* HB_UNICODE_COMBINING_CLASS_NOT_REORDERED */
   1, /* HB_UNICODE_COMBINING_CLASS_OVERLAY */
   2, 3, 4, 5, 6,
   7, /* HB_UNICODE_COMBINING_CLASS_NUKTA */
   8, /* HB_UNICODE_COMBINING_CLASS_KANA_VOICING */
   9, /* HB_UNICODE_COMBINING_CLASS_VIRAMA */

   /* Hebrew */
   HB_MODIFIED_COMBINING_CLASS_CCC10,
   HB_MODIFIED_COMBINING_CLASS_CCC11,
   HB_MODIFIED_COMBINING_CLASS_CCC12,
   HB_MODIFIED_COMBINING_CLASS_CCC13,
   HB_MODIFIED_COMBINING_CLASS_CCC14,
   HB_MODIFIED_COMBINING_CLASS_CCC15,
   HB_MODIFIED_COMBINING_CLASS_CCC16,
   HB_MODIFIED_COMBINING_CLASS_CCC17,
   HB_MODIFIED_COMBINING_CLASS_CCC18,
   HB_MODIFIED_COMBINING_CLASS_CCC19,
   HB_MODIFIED_COMBINING_CLASS_CCC20,
   HB_MODIFIED_COMBINING_CLASS_CCC21,
   HB_MODIFIED_COMBINING_CLASS_CCC22,
   HB_MODIFIED_COMBINING_CLASS_CCC23,
   HB_MODIFIED_COMBINING_CLASS_CCC24,
   HB_MODIFIED_COMBINING_CLASS_CCC25,
   HB_MODIFIED_COMBINING_CLASS_CCC26,

   /* Arabic */
   HB_MODIFIED_COMBINING_CLASS_CCC27,
   HB_MODIFIED_COMBINING_CLASS_CCC28,
   HB_MODIFIED_COMBINING_CLASS_CCC29,
   HB_MODIFIED_COMBINING_CLASS_CCC30,
   HB_MODIFIED_COMBINING_CLASS_CCC31,
   HB_MODIFIED_COMBINING_CLASS_CCC32,
   HB_MODIFIED_COMBINING_CLASS_CCC33,
   HB_MODIFIED_COMBINING_CLASS_CCC34,
   HB_MODIFIED_COMBINING_CLASS_CCC35,

   /* Syriac */
   HB_MODIFIED_COMBINING_CLASS_CCC36,

   37, 38, 39,
   40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
   60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,
   80, 81, 82, 83,

   /* Telugu */
   HB_MODIFIED_COMBINING_CLASS_CCC84,
   85, 86, 87, 88, 89, 90,
   HB_MODIFIED_COMBINING_CLASS_CCC91,
   92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102,

   /* Thai */
   HB_MODIFIED_COMBINING_CLASS_CCC103,
   104, 105, 106,
   HB_MODIFIED_COMBINING_CLASS_CCC107,
   108, 109, 110, 111, 112, 113, 114, 115, 116, 117,

   /* Lao */
   HB_MODIFIED_COMBINING_CLASS_CCC118,
   119, 120, 121,
   HB_MODIFIED_COMBINING_CLASS_CCC122,
   123, 124, 125, 126, 127, 128,

   /* Tibetan */
   HB_MODIFIED_COMBINING_CLASS_CCC129,
   HB_MODIFIED_COMBINING_CLASS_CCC130,
   131,
   HB_MODIFIED_COMBINING_CLASS_CCC132,
   133, 134, 135, 136, 137, 138, 139,


   140, 141, 142, 143, 144, 145, 146, 147, 148, 149,
   150, 151, 152, 153, 154, 155, 156, 157, 158, 159,
   160, 161, 162, 163, 164, 165, 166, 167, 168, 169,
   170, 171, 172, 173, 174, 175, 176, 177, 178, 179,
   180, 181, 182, 183, 184, 185, 186, 187, 188, 189,
   190, 191, 192, 193, 194, 195, 196, 197, 198, 199,

   200, /* HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT */
   201,
   202, /* HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW */
   203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213,
   214, /* HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE */
   215,
   216, /* HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT */
   217,
   218, /* HB_UNICODE_COMBINING_CLASS_BELOW_LEFT */
   219,
   220, /* HB_UNICODE_COMBINING_CLASS_BELOW */
   221,
   222, /* HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT */
   223,
   224, /* HB_UNICODE_COMBINING_CLASS_LEFT */
   225,
   226, /* HB_UNICODE_COMBINING_CLASS_RIGHT */
   227,
   228, /* HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT */
   229,
   230, /* HB_UNICODE_COMBINING_CLASS_ABOVE */
   231,
   232, /* HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT */
   233, /* HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW */
   234, /* HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE */
   235, 236, 237, 238, 239,
   240, /* HB_UNICODE_COMBINING_CLASS_IOTA_SUBSCRIPT */
   241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254,
   255, /* HB_UNICODE_COMBINING_CLASS_INVALID */
 };
	/*
	* Copyright © 2009 Red Hat, Inc.
	* Copyright © 2011 Codethink Limited
	* Copyright © 2010,2011,2012 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.
	*
	* Red Hat Author(s): Behdad Esfahbod
	* Codethink Author(s): Ryan Lortie
	* Google Author(s): Behdad Esfahbod
	*/

	#include "hb-private.hh"

	#include "hb-unicode-private.hh"



	/*
	* hb_unicode_funcs_t
	*/

	static hb_unicode_combining_class_t
	hb_unicode_combining_class_nil (hb_unicode_funcs_t *ufuncs HB_UNUSED,
	hb_codepoint_t unicode HB_UNUSED,
	void *user_data HB_UNUSED)
	{
	return HB_UNICODE_COMBINING_CLASS_NOT_REORDERED;
	}

	static unsigned int
	hb_unicode_eastasian_width_nil (hb_unicode_funcs_t *ufuncs HB_UNUSED,
	hb_codepoint_t unicode HB_UNUSED,
	void *user_data HB_UNUSED)
	{
	return 1;
	}

	static hb_unicode_general_category_t
	hb_unicode_general_category_nil (hb_unicode_funcs_t *ufuncs HB_UNUSED,
	hb_codepoint_t unicode HB_UNUSED,
	void *user_data HB_UNUSED)
	{
	return HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER;
	}

	static hb_codepoint_t
	hb_unicode_mirroring_nil (hb_unicode_funcs_t *ufuncs HB_UNUSED,
	hb_codepoint_t unicode HB_UNUSED,
	void *user_data HB_UNUSED)
	{
	return unicode;
	}

	static hb_script_t
	hb_unicode_script_nil (hb_unicode_funcs_t *ufuncs HB_UNUSED,
	hb_codepoint_t unicode HB_UNUSED,
	void *user_data HB_UNUSED)
	{
	return HB_SCRIPT_UNKNOWN;
	}

	static hb_bool_t
	hb_unicode_compose_nil (hb_unicode_funcs_t *ufuncs HB_UNUSED,
	hb_codepoint_t a HB_UNUSED,
	hb_codepoint_t b HB_UNUSED,
	hb_codepoint_t *ab HB_UNUSED,
	void *user_data HB_UNUSED)
	{
	return false;
	}

	static hb_bool_t
	hb_unicode_decompose_nil (hb_unicode_funcs_t *ufuncs HB_UNUSED,
	hb_codepoint_t ab HB_UNUSED,
	hb_codepoint_t *a HB_UNUSED,
	hb_codepoint_t *b HB_UNUSED,
	void *user_data HB_UNUSED)
	{
	return false;
	}


	static unsigned int
	hb_unicode_decompose_compatibility_nil (hb_unicode_funcs_t *ufuncs HB_UNUSED,
	hb_codepoint_t u HB_UNUSED,
	hb_codepoint_t *decomposed HB_UNUSED,
	void *user_data HB_UNUSED)
	{
	return 0;
	}


	#define HB_UNICODE_FUNCS_IMPLEMENT_SET \
	HB_UNICODE_FUNCS_IMPLEMENT (glib) \
	HB_UNICODE_FUNCS_IMPLEMENT (icu) \
	HB_UNICODE_FUNCS_IMPLEMENT (ucdn) \
	HB_UNICODE_FUNCS_IMPLEMENT (nil) \
	/* ^--- Add new callbacks before nil */

	#define hb_nil_get_unicode_funcs hb_unicode_funcs_get_empty

	/* Prototype them all */
	#define HB_UNICODE_FUNCS_IMPLEMENT(set) \
	extern "C" hb_unicode_funcs_t *hb_##set##_get_unicode_funcs (void);
	HB_UNICODE_FUNCS_IMPLEMENT_SET
	#undef HB_UNICODE_FUNCS_IMPLEMENT


	hb_unicode_funcs_t *
	hb_unicode_funcs_get_default (void)
	{
	#define HB_UNICODE_FUNCS_IMPLEMENT(set) \
	return hb_##set##_get_unicode_funcs ();

	#ifdef HAVE_GLIB
	HB_UNICODE_FUNCS_IMPLEMENT(glib)
	#elif defined(HAVE_ICU)
	HB_UNICODE_FUNCS_IMPLEMENT(icu)
	#elif defined(HAVE_UCDN)
	HB_UNICODE_FUNCS_IMPLEMENT(ucdn)
	#else
	#define HB_UNICODE_FUNCS_NIL 1
	HB_UNICODE_FUNCS_IMPLEMENT(nil)
	#endif

	#undef HB_UNICODE_FUNCS_IMPLEMENT
	}

	#if !defined(HB_NO_UNICODE_FUNCS) && defined(HB_UNICODE_FUNCS_NIL)
	#pragma message("Could not find any Unicode functions implementation, you have to provide your own.")
	#pragma message("To suppress this warnings, define HB_NO_UNICODE_FUNCS.")
	#endif

	hb_unicode_funcs_t *
	hb_unicode_funcs_create (hb_unicode_funcs_t *parent)
	{
	hb_unicode_funcs_t *ufuncs;

	if (!(ufuncs = hb_object_create<hb_unicode_funcs_t> ()))
	return hb_unicode_funcs_get_empty ();

	if (!parent)
	parent = hb_unicode_funcs_get_empty ();

	hb_unicode_funcs_make_immutable (parent);
	ufuncs->parent = hb_unicode_funcs_reference (parent);

	ufuncs->func = parent->func;

	/* We can safely copy user_data from parent since we hold a reference
	* onto it and it's immutable. We should not copy the destroy notifiers
	* though. */
	ufuncs->user_data = parent->user_data;

	return ufuncs;
	}


	const hb_unicode_funcs_t _hb_unicode_funcs_nil = {
	HB_OBJECT_HEADER_STATIC,

	NULL, /* parent */
	true, /* immutable */
	{
	#define HB_UNICODE_FUNC_IMPLEMENT(name) hb_unicode_##name##_nil,
	HB_UNICODE_FUNCS_IMPLEMENT_CALLBACKS
	#undef HB_UNICODE_FUNC_IMPLEMENT
	}
	};

	hb_unicode_funcs_t *
	hb_unicode_funcs_get_empty (void)
	{
	return const_cast<hb_unicode_funcs_t *> (&_hb_unicode_funcs_nil);
	}

	hb_unicode_funcs_t *
	hb_unicode_funcs_reference (hb_unicode_funcs_t *ufuncs)
	{
	return hb_object_reference (ufuncs);
	}

	void
	hb_unicode_funcs_destroy (hb_unicode_funcs_t *ufuncs)
	{
	if (!hb_object_destroy (ufuncs)) return;

	#define HB_UNICODE_FUNC_IMPLEMENT(name) \
	if (ufuncs->destroy.name) ufuncs->destroy.name (ufuncs->user_data.name);
	HB_UNICODE_FUNCS_IMPLEMENT_CALLBACKS
	#undef HB_UNICODE_FUNC_IMPLEMENT

	hb_unicode_funcs_destroy (ufuncs->parent);

	free (ufuncs);
	}

	hb_bool_t
	hb_unicode_funcs_set_user_data (hb_unicode_funcs_t *ufuncs,
	hb_user_data_key_t *key,
	void * data,
	hb_destroy_func_t destroy,
	hb_bool_t replace)
	{
	return hb_object_set_user_data (ufuncs, key, data, destroy, replace);
	}

	void *
	hb_unicode_funcs_get_user_data (hb_unicode_funcs_t *ufuncs,
	hb_user_data_key_t *key)
	{
	return hb_object_get_user_data (ufuncs, key);
	}


	void
	hb_unicode_funcs_make_immutable (hb_unicode_funcs_t *ufuncs)
	{
	if (hb_object_is_inert (ufuncs))
	return;

	ufuncs->immutable = true;
	}

	hb_bool_t
	hb_unicode_funcs_is_immutable (hb_unicode_funcs_t *ufuncs)
	{
	return ufuncs->immutable;
	}

	hb_unicode_funcs_t *
	hb_unicode_funcs_get_parent (hb_unicode_funcs_t *ufuncs)
	{
	return ufuncs->parent ? ufuncs->parent : hb_unicode_funcs_get_empty ();
	}


	#define HB_UNICODE_FUNC_IMPLEMENT(name) \
	\
	void \
	hb_unicode_funcs_set_##name##_func (hb_unicode_funcs_t *ufuncs, \
	hb_unicode_##name##_func_t func, \
	void *user_data, \
	hb_destroy_func_t destroy) \
	{ \
	if (ufuncs->immutable) \
	return; \
	\
	if (ufuncs->destroy.name) \
	ufuncs->destroy.name (ufuncs->user_data.name); \
	\
	if (func) { \
	ufuncs->func.name = func; \
	ufuncs->user_data.name = user_data; \
	ufuncs->destroy.name = destroy; \
	} else { \
	ufuncs->func.name = ufuncs->parent->func.name; \
	ufuncs->user_data.name = ufuncs->parent->user_data.name; \
	ufuncs->destroy.name = NULL; \
	} \
	}

	HB_UNICODE_FUNCS_IMPLEMENT_CALLBACKS
	#undef HB_UNICODE_FUNC_IMPLEMENT


	#define HB_UNICODE_FUNC_IMPLEMENT(return_type, name) \
	\
	return_type \
	hb_unicode_##name (hb_unicode_funcs_t *ufuncs, \
	hb_codepoint_t unicode) \
	{ \
	return ufuncs->name (unicode); \
	}
	HB_UNICODE_FUNCS_IMPLEMENT_CALLBACKS_SIMPLE
	#undef HB_UNICODE_FUNC_IMPLEMENT

	hb_bool_t
	hb_unicode_compose (hb_unicode_funcs_t *ufuncs,
	hb_codepoint_t a,
	hb_codepoint_t b,
	hb_codepoint_t *ab)
	{
	return ufuncs->compose (a, b, ab);
	}

	hb_bool_t
	hb_unicode_decompose (hb_unicode_funcs_t *ufuncs,
	hb_codepoint_t ab,
	hb_codepoint_t *a,
	hb_codepoint_t *b)
	{
	return ufuncs->decompose (ab, a, b);
	}

	unsigned int
	hb_unicode_decompose_compatibility (hb_unicode_funcs_t *ufuncs,
	hb_codepoint_t u,
	hb_codepoint_t *decomposed)
	{
	return ufuncs->decompose_compatibility (u, decomposed);
	}


	/* See hb-unicode-private.hh for details. */
	const uint8_t
	_hb_modified_combining_class[256] =
	{
	0, /* HB_UNICODE_COMBINING_CLASS_NOT_REORDERED */
	1, /* HB_UNICODE_COMBINING_CLASS_OVERLAY */
	2, 3, 4, 5, 6,
	7, /* HB_UNICODE_COMBINING_CLASS_NUKTA */
	8, /* HB_UNICODE_COMBINING_CLASS_KANA_VOICING */
	9, /* HB_UNICODE_COMBINING_CLASS_VIRAMA */

	/* Hebrew */
	HB_MODIFIED_COMBINING_CLASS_CCC10,
	HB_MODIFIED_COMBINING_CLASS_CCC11,
	HB_MODIFIED_COMBINING_CLASS_CCC12,
	HB_MODIFIED_COMBINING_CLASS_CCC13,
	HB_MODIFIED_COMBINING_CLASS_CCC14,
	HB_MODIFIED_COMBINING_CLASS_CCC15,
	HB_MODIFIED_COMBINING_CLASS_CCC16,
	HB_MODIFIED_COMBINING_CLASS_CCC17,
	HB_MODIFIED_COMBINING_CLASS_CCC18,
	HB_MODIFIED_COMBINING_CLASS_CCC19,
	HB_MODIFIED_COMBINING_CLASS_CCC20,
	HB_MODIFIED_COMBINING_CLASS_CCC21,
	HB_MODIFIED_COMBINING_CLASS_CCC22,
	HB_MODIFIED_COMBINING_CLASS_CCC23,
	HB_MODIFIED_COMBINING_CLASS_CCC24,
	HB_MODIFIED_COMBINING_CLASS_CCC25,
	HB_MODIFIED_COMBINING_CLASS_CCC26,

	/* Arabic */
	HB_MODIFIED_COMBINING_CLASS_CCC27,
	HB_MODIFIED_COMBINING_CLASS_CCC28,
	HB_MODIFIED_COMBINING_CLASS_CCC29,
	HB_MODIFIED_COMBINING_CLASS_CCC30,
	HB_MODIFIED_COMBINING_CLASS_CCC31,
	HB_MODIFIED_COMBINING_CLASS_CCC32,
	HB_MODIFIED_COMBINING_CLASS_CCC33,
	HB_MODIFIED_COMBINING_CLASS_CCC34,
	HB_MODIFIED_COMBINING_CLASS_CCC35,

	/* Syriac */
	HB_MODIFIED_COMBINING_CLASS_CCC36,

	37, 38, 39,
	40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
	60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,
	80, 81, 82, 83,

	/* Telugu */
	HB_MODIFIED_COMBINING_CLASS_CCC84,
	85, 86, 87, 88, 89, 90,
	HB_MODIFIED_COMBINING_CLASS_CCC91,
	92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102,

	/* Thai */
	HB_MODIFIED_COMBINING_CLASS_CCC103,
	104, 105, 106,
	HB_MODIFIED_COMBINING_CLASS_CCC107,
	108, 109, 110, 111, 112, 113, 114, 115, 116, 117,

	/* Lao */
	HB_MODIFIED_COMBINING_CLASS_CCC118,
	119, 120, 121,
	HB_MODIFIED_COMBINING_CLASS_CCC122,
	123, 124, 125, 126, 127, 128,

	/* Tibetan */
	HB_MODIFIED_COMBINING_CLASS_CCC129,
	HB_MODIFIED_COMBINING_CLASS_CCC130,
	131,
	HB_MODIFIED_COMBINING_CLASS_CCC132,
	133, 134, 135, 136, 137, 138, 139,


	140, 141, 142, 143, 144, 145, 146, 147, 148, 149,
	150, 151, 152, 153, 154, 155, 156, 157, 158, 159,
	160, 161, 162, 163, 164, 165, 166, 167, 168, 169,
	170, 171, 172, 173, 174, 175, 176, 177, 178, 179,
	180, 181, 182, 183, 184, 185, 186, 187, 188, 189,
	190, 191, 192, 193, 194, 195, 196, 197, 198, 199,

	200, /* HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT */
	201,
	202, /* HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW */
	203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213,
	214, /* HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE */
	215,
	216, /* HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT */
	217,
	218, /* HB_UNICODE_COMBINING_CLASS_BELOW_LEFT */
	219,
	220, /* HB_UNICODE_COMBINING_CLASS_BELOW */
	221,
	222, /* HB_UNICODE_COMBINING_CLASS_BELOW_RIGHT */
	223,
	224, /* HB_UNICODE_COMBINING_CLASS_LEFT */
	225,
	226, /* HB_UNICODE_COMBINING_CLASS_RIGHT */
	227,
	228, /* HB_UNICODE_COMBINING_CLASS_ABOVE_LEFT */
	229,
	230, /* HB_UNICODE_COMBINING_CLASS_ABOVE */
	231,
	232, /* HB_UNICODE_COMBINING_CLASS_ABOVE_RIGHT */
	233, /* HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW */
	234, /* HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE */
	235, 236, 237, 238, 239,
	240, /* HB_UNICODE_COMBINING_CLASS_IOTA_SUBSCRIPT */
	241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254,
	255, /* HB_UNICODE_COMBINING_CLASS_INVALID */
	};