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 /*

  * Copyright © 2007,2008,2009,2010  Red Hat, Inc.

  * Copyright © 2010,2012  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

  * Google Author(s): Behdad Esfahbod

  */

 #ifndef HB_OT_LAYOUT_GSUBGPOS_PRIVATE_HH

 #define HB_OT_LAYOUT_GSUBGPOS_PRIVATE_HH

 #include "hb-buffer-private.hh"

 #include "hb-ot-layout-gdef-table.hh"

 #include "hb-set-private.hh"

 namespace OT {

 #define TRACE_DISPATCH(this) \

 	hb_auto_trace_t<context_t::max_debug_depth, typename context_t::return_t> trace \

 	(&c->debug_depth, c->get_name (), this, HB_FUNC, \

 	 "");

 #ifndef HB_DEBUG_CLOSURE

 #define HB_DEBUG_CLOSURE (HB_DEBUG+0)

 #endif

 #define TRACE_CLOSURE(this) \

 	hb_auto_trace_t<HB_DEBUG_CLOSURE, hb_void_t> trace \

 	(&c->debug_depth, c->get_name (), this, HB_FUNC, \

 	 "");

 struct hb_closure_context_t

 {

   inline const char *get_name (void) { return "CLOSURE"; }

   static const unsigned int max_debug_depth = HB_DEBUG_CLOSURE;

   typedef hb_void_t return_t;

   typedef return_t (*recurse_func_t) (hb_closure_context_t *c, unsigned int lookup_index);

   template <typename T>

   inline return_t dispatch (const T &obj) { obj.closure (this); return HB_VOID; }

   static return_t default_return_value (void) { return HB_VOID; }

   bool stop_sublookup_iteration (return_t r HB_UNUSED) const { return false; }

   return_t recurse (unsigned int lookup_index)

   {

     if (unlikely (nesting_level_left == 0 || !recurse_func))

       return default_return_value ();

     nesting_level_left--;

     recurse_func (this, lookup_index);

     nesting_level_left++;

     return HB_VOID;

   }

   hb_face_t *face;

   hb_set_t *glyphs;

   recurse_func_t recurse_func;

   unsigned int nesting_level_left;

   unsigned int debug_depth;

   hb_closure_context_t (hb_face_t *face_,

 			hb_set_t *glyphs_,

 		        unsigned int nesting_level_left_ = MAX_NESTING_LEVEL) :

 			  face (face_),

 			  glyphs (glyphs_),

 			  recurse_func (NULL),

 			  nesting_level_left (nesting_level_left_),

 			  debug_depth (0) {}

   void set_recurse_func (recurse_func_t func) { recurse_func = func; }

 };

 #ifndef HB_DEBUG_WOULD_APPLY

 #define HB_DEBUG_WOULD_APPLY (HB_DEBUG+0)

 #endif

 #define TRACE_WOULD_APPLY(this) \

 	hb_auto_trace_t<HB_DEBUG_WOULD_APPLY, bool> trace \

 	(&c->debug_depth, c->get_name (), this, HB_FUNC, \

 	 "%d glyphs", c->len);

 struct hb_would_apply_context_t

 {

   inline const char *get_name (void) { return "WOULD_APPLY"; }

   static const unsigned int max_debug_depth = HB_DEBUG_WOULD_APPLY;

   typedef bool return_t;

   template <typename T>

   inline return_t dispatch (const T &obj) { return obj.would_apply (this); }

   static return_t default_return_value (void) { return false; }

   bool stop_sublookup_iteration (return_t r) const { return r; }

   hb_face_t *face;

   const hb_codepoint_t *glyphs;

   unsigned int len;

   bool zero_context;

   unsigned int debug_depth;

   hb_would_apply_context_t (hb_face_t *face_,

 			    const hb_codepoint_t *glyphs_,

 			    unsigned int len_,

 			    bool zero_context_) :

 			      face (face_),

 			      glyphs (glyphs_),

 			      len (len_),

 			      zero_context (zero_context_),

 			      debug_depth (0) {}

 };

 #ifndef HB_DEBUG_COLLECT_GLYPHS

 #define HB_DEBUG_COLLECT_GLYPHS (HB_DEBUG+0)

 #endif

 #define TRACE_COLLECT_GLYPHS(this) \

 	hb_auto_trace_t<HB_DEBUG_COLLECT_GLYPHS, hb_void_t> trace \

 	(&c->debug_depth, c->get_name (), this, HB_FUNC, \

 	 "");

 struct hb_collect_glyphs_context_t

 {

   inline const char *get_name (void) { return "COLLECT_GLYPHS"; }

   static const unsigned int max_debug_depth = HB_DEBUG_COLLECT_GLYPHS;

   typedef hb_void_t return_t;

   typedef return_t (*recurse_func_t) (hb_collect_glyphs_context_t *c, unsigned int lookup_index);

   template <typename T>

   inline return_t dispatch (const T &obj) { obj.collect_glyphs (this); return HB_VOID; }

   static return_t default_return_value (void) { return HB_VOID; }

   bool stop_sublookup_iteration (return_t r HB_UNUSED) const { return false; }

   return_t recurse (unsigned int lookup_index)

   {

     if (unlikely (nesting_level_left == 0 || !recurse_func))

       return default_return_value ();

     /* Note that GPOS sets recurse_func to NULL already, so it doesn't get

      * past the previous check.  For GSUB, we only want to collect the output

      * glyphs in the recursion.  If output is not requested, we can go home now.

      *

      * Note further, that the above is not exactly correct.  A recursed lookup

      * is allowed to match input that is not matched in the context, but that's

      * not how most fonts are built.  It's possible to relax that and recurse

      * with all sets here if it proves to be an issue.

      */

     if (output == hb_set_get_empty ())

       return HB_VOID;

     hb_set_t *old_before = before;

     hb_set_t *old_input  = input;

     hb_set_t *old_after  = after;

     before = input = after = hb_set_get_empty ();

     nesting_level_left--;

     recurse_func (this, lookup_index);

     nesting_level_left++;

     before = old_before;

     input  = old_input;

     after  = old_after;

     return HB_VOID;

   }

   hb_face_t *face;

   hb_set_t *before;

   hb_set_t *input;

   hb_set_t *after;

   hb_set_t *output;

   recurse_func_t recurse_func;

   unsigned int nesting_level_left;

   unsigned int debug_depth;

   hb_collect_glyphs_context_t (hb_face_t *face_,

 			       hb_set_t  *glyphs_before, /* OUT. May be NULL */

 			       hb_set_t  *glyphs_input,  /* OUT. May be NULL */

 			       hb_set_t  *glyphs_after,  /* OUT. May be NULL */

 			       hb_set_t  *glyphs_output, /* OUT. May be NULL */

 			       unsigned int nesting_level_left_ = MAX_NESTING_LEVEL) :

 			      face (face_),

 			      before (glyphs_before ? glyphs_before : hb_set_get_empty ()),

 			      input  (glyphs_input  ? glyphs_input  : hb_set_get_empty ()),

 			      after  (glyphs_after  ? glyphs_after  : hb_set_get_empty ()),

 			      output (glyphs_output ? glyphs_output : hb_set_get_empty ()),

 			      recurse_func (NULL),

 			      nesting_level_left (nesting_level_left_),

 			      debug_depth (0) {}

   void set_recurse_func (recurse_func_t func) { recurse_func = func; }

 };

 struct hb_get_coverage_context_t

 {

   inline const char *get_name (void) { return "GET_COVERAGE"; }

   static const unsigned int max_debug_depth = 0;

   typedef const Coverage &return_t;

   template <typename T>

   inline return_t dispatch (const T &obj) { return obj.get_coverage (); }

   static return_t default_return_value (void) { return Null(Coverage); }

   hb_get_coverage_context_t (void) :

 			    debug_depth (0) {}

   unsigned int debug_depth;

 };

 #ifndef HB_DEBUG_APPLY

 #define HB_DEBUG_APPLY (HB_DEBUG+0)

 #endif

 #define TRACE_APPLY(this) \

 	hb_auto_trace_t<HB_DEBUG_APPLY, bool> trace \

 	(&c->debug_depth, c->get_name (), this, HB_FUNC, \

 	 "idx %d codepoint %u", c->buffer->idx, c->buffer->cur().codepoint);

 struct hb_apply_context_t

 {

   inline const char *get_name (void) { return "APPLY"; }

   static const unsigned int max_debug_depth = HB_DEBUG_APPLY;

   typedef bool return_t;

   typedef return_t (*recurse_func_t) (hb_apply_context_t *c, unsigned int lookup_index);

   template <typename T>

   inline return_t dispatch (const T &obj) { return obj.apply (this); }

   static return_t default_return_value (void) { return false; }

   bool stop_sublookup_iteration (return_t r) const { return r; }

   return_t recurse (unsigned int lookup_index)

   {

     if (unlikely (nesting_level_left == 0 || !recurse_func))

       return default_return_value ();

     nesting_level_left--;

     bool ret = recurse_func (this, lookup_index);

     nesting_level_left++;

     return ret;

   }

   unsigned int table_index; /* GSUB/GPOS */

   hb_font_t *font;

   hb_face_t *face;

   hb_buffer_t *buffer;

   hb_direction_t direction;

   hb_mask_t lookup_mask;

   bool auto_zwj;

   recurse_func_t recurse_func;

   unsigned int nesting_level_left;

   unsigned int lookup_props;

   const GDEF &gdef;

   bool has_glyph_classes;

   unsigned int debug_depth;

   hb_apply_context_t (unsigned int table_index_,

 		      hb_font_t *font_,

 		      hb_buffer_t *buffer_) :

 			table_index (table_index_),

 			font (font_), face (font->face), buffer (buffer_),

 			direction (buffer_->props.direction),

 			lookup_mask (1),

 			auto_zwj (true),

 			recurse_func (NULL),

 			nesting_level_left (MAX_NESTING_LEVEL),

 			lookup_props (0),

 			gdef (*hb_ot_layout_from_face (face)->gdef),

 			has_glyph_classes (gdef.has_glyph_classes ()),

 			debug_depth (0) {}

   inline void set_lookup_mask (hb_mask_t mask) { lookup_mask = mask; }

   inline void set_auto_zwj (bool auto_zwj_) { auto_zwj = auto_zwj_; }

   inline void set_recurse_func (recurse_func_t func) { recurse_func = func; }

   inline void set_lookup_props (unsigned int lookup_props_) { lookup_props = lookup_props_; }

   inline void set_lookup (const Lookup &l) { lookup_props = l.get_props (); }

   struct matcher_t

   {

     inline matcher_t (void) :

 	     lookup_props (0),

 	     ignore_zwnj (false),

 	     ignore_zwj (false),

 	     mask (-1),

 #define arg1(arg) (arg) /* Remove the macro to see why it's needed! */

 	     syllable arg1(0),

 #undef arg1

 	     match_func (NULL),

 	     match_data (NULL) {};

     typedef bool (*match_func_t) (hb_codepoint_t glyph_id, const USHORT &value, const void *data);

     inline void set_ignore_zwnj (bool ignore_zwnj_) { ignore_zwnj = ignore_zwnj_; }

     inline void set_ignore_zwj (bool ignore_zwj_) { ignore_zwj = ignore_zwj_; }

     inline void set_lookup_props (unsigned int lookup_props_) { lookup_props = lookup_props_; }

     inline void set_mask (hb_mask_t mask_) { mask = mask_; }

     inline void set_syllable (uint8_t syllable_)  { syllable = syllable_; }

     inline void set_match_func (match_func_t match_func_,

 				const void *match_data_)

     { match_func = match_func_; match_data = match_data_; }

     enum may_match_t {

       MATCH_NO,

       MATCH_YES,

       MATCH_MAYBE

     };

     inline may_match_t may_match (const hb_glyph_info_t &info,

 				  const USHORT          *glyph_data) const

     {

       if (!(info.mask & mask) ||

 	  (syllable && syllable != info.syllable ()))

 	return MATCH_NO;

       if (match_func)

         return match_func (info.codepoint, *glyph_data, match_data) ? MATCH_YES : MATCH_NO;

       return MATCH_MAYBE;

     }

     enum may_skip_t {

       SKIP_NO,

       SKIP_YES,

       SKIP_MAYBE

     };

     inline may_skip_t

     may_skip (const hb_apply_context_t *c,

 	      const hb_glyph_info_t    &info) const

     {

       unsigned int property;

       property = _hb_glyph_info_get_glyph_props (&info);

       if (!c->match_properties (info.codepoint, property, lookup_props))

 	return SKIP_YES;

       if (unlikely (_hb_glyph_info_is_default_ignorable (&info) &&

 		    (ignore_zwnj || !_hb_glyph_info_is_zwnj (&info)) &&

 		    (ignore_zwj || !_hb_glyph_info_is_zwj (&info)) &&

 		    !_hb_glyph_info_ligated (&info)))

 	return SKIP_MAYBE;

       return SKIP_NO;

     }

     protected:

     unsigned int lookup_props;

     bool ignore_zwnj;

     bool ignore_zwj;

     hb_mask_t mask;

     uint8_t syllable;

     match_func_t match_func;

     const void *match_data;

   };

   struct skipping_forward_iterator_t

   {

     inline skipping_forward_iterator_t (hb_apply_context_t *c_,

 					unsigned int start_index_,

 					unsigned int num_items_,

 					bool context_match = false) :

 					 idx (start_index_),

 					 c (c_),

 					 match_glyph_data (NULL),

 					 num_items (num_items_),

 					 end (c->buffer->len)

     {

       matcher.set_lookup_props (c->lookup_props);

       /* Ignore ZWNJ if we are matching GSUB context, or matching GPOS. */

       matcher.set_ignore_zwnj (context_match || c->table_index == 1);

       /* Ignore ZWJ if we are matching GSUB context, or matching GPOS, or if asked to. */

       matcher.set_ignore_zwj (context_match || c->table_index == 1 || c->auto_zwj);

       if (!context_match)

 	matcher.set_mask (c->lookup_mask);

       matcher.set_syllable (start_index_ == c->buffer->idx ? c->buffer->cur().syllable () : 0);

     }

     inline void set_lookup_props (unsigned int lookup_props) { matcher.set_lookup_props (lookup_props); }

     inline void set_syllable (unsigned int syllable) { matcher.set_syllable (syllable); }

     inline void set_match_func (matcher_t::match_func_t match_func,

 				const void *match_data,

 				const USHORT glyph_data[])

     {

       matcher.set_match_func (match_func, match_data);

       match_glyph_data = glyph_data;

     }

     inline bool has_no_chance (void) const { return unlikely (num_items && idx + num_items >= end); }

     inline void reject (void) { num_items++; match_glyph_data--; }

     inline bool next (void)

     {

       assert (num_items > 0);

       while (!has_no_chance ())

       {

 	idx++;

 	const hb_glyph_info_t &info = c->buffer->info[idx];

 	matcher_t::may_skip_t skip = matcher.may_skip (c, info);

 	if (unlikely (skip == matcher_t::SKIP_YES))

 	  continue;

 	matcher_t::may_match_t match = matcher.may_match (info, match_glyph_data);

 	if (match == matcher_t::MATCH_YES ||

 	    (match == matcher_t::MATCH_MAYBE &&

 	     skip == matcher_t::SKIP_NO))

 	{

 	  num_items--;

 	  match_glyph_data++;

 	  return true;

 	}

 	if (skip == matcher_t::SKIP_NO)

 	  return false;

       }

       return false;

     }

     unsigned int idx;

     protected:

     hb_apply_context_t *c;

     matcher_t matcher;

     const USHORT *match_glyph_data;

     unsigned int num_items;

     unsigned int end;

   };

   struct skipping_backward_iterator_t

   {

     inline skipping_backward_iterator_t (hb_apply_context_t *c_,

 					 unsigned int start_index_,

 					 unsigned int num_items_,

 					 bool context_match = false) :

 					  idx (start_index_),

 					  c (c_),

 					  match_glyph_data (NULL),

 					  num_items (num_items_)

     {

       matcher.set_lookup_props (c->lookup_props);

       /* Ignore ZWNJ if we are matching GSUB context, or matching GPOS. */

       matcher.set_ignore_zwnj (context_match || c->table_index == 1);

       /* Ignore ZWJ if we are matching GSUB context, or matching GPOS, or if asked to. */

       matcher.set_ignore_zwj (context_match || c->table_index == 1 || c->auto_zwj);

       if (!context_match)

 	matcher.set_mask (c->lookup_mask);

       matcher.set_syllable (start_index_ == c->buffer->idx ? c->buffer->cur().syllable () : 0);

     }

     inline void set_lookup_props (unsigned int lookup_props) { matcher.set_lookup_props (lookup_props); }

     inline void set_syllable (unsigned int syllable) { matcher.set_syllable (syllable); }

     inline void set_match_func (matcher_t::match_func_t match_func,

 				const void *match_data,

 				const USHORT glyph_data[])

     {

       matcher.set_match_func (match_func, match_data);

       match_glyph_data = glyph_data;

     }

     inline bool has_no_chance (void) const { return unlikely (idx < num_items); }

     inline void reject (void) { num_items++; }

     inline bool prev (void)

     {

       assert (num_items > 0);

       while (!has_no_chance ())

       {

 	idx--;

 	const hb_glyph_info_t &info = c->buffer->out_info[idx];

 	matcher_t::may_skip_t skip = matcher.may_skip (c, info);

 	if (unlikely (skip == matcher_t::SKIP_YES))

 	  continue;

 	matcher_t::may_match_t match = matcher.may_match (info, match_glyph_data);

 	if (match == matcher_t::MATCH_YES ||

 	    (match == matcher_t::MATCH_MAYBE &&

 	     skip == matcher_t::SKIP_NO))

 	{

 	  num_items--;

 	  match_glyph_data++;

 	  return true;

 	}

 	if (skip == matcher_t::SKIP_NO)

 	  return false;

       }

       return false;

     }

     unsigned int idx;

     protected:

     hb_apply_context_t *c;

     matcher_t matcher;

     const USHORT *match_glyph_data;

     unsigned int num_items;

   };

   inline bool

   match_properties_mark (hb_codepoint_t  glyph,

 			 unsigned int    glyph_props,

 			 unsigned int    lookup_props) const

   {

     /* If using mark filtering sets, the high short of

      * lookup_props has the set index.

      */

     if (lookup_props & LookupFlag::UseMarkFilteringSet)

       return gdef.mark_set_covers (lookup_props >> 16, glyph);

     /* The second byte of lookup_props has the meaning

      * "ignore marks of attachment type different than

      * the attachment type specified."

      */

     if (lookup_props & LookupFlag::MarkAttachmentType)

       return (lookup_props & LookupFlag::MarkAttachmentType) == (glyph_props & LookupFlag::MarkAttachmentType);

     return true;

   }

   inline bool

   match_properties (hb_codepoint_t  glyph,

 		    unsigned int    glyph_props,

 		    unsigned int    lookup_props) const

   {

     /* Not covered, if, for example, glyph class is ligature and

      * lookup_props includes LookupFlags::IgnoreLigatures

      */

     if (glyph_props & lookup_props & LookupFlag::IgnoreFlags)

       return false;

     if (unlikely (glyph_props & HB_OT_LAYOUT_GLYPH_PROPS_MARK))

       return match_properties_mark (glyph, glyph_props, lookup_props);

     return true;

   }

   inline bool

   check_glyph_property (hb_glyph_info_t *info,

 			unsigned int  lookup_props) const

   {

     unsigned int property;

     property = _hb_glyph_info_get_glyph_props (info);

     return match_properties (info->codepoint, property, lookup_props);

   }

   inline void _set_glyph_props (hb_codepoint_t glyph_index,

 			  unsigned int class_guess = 0,

 			  bool ligature = false) const

   {

     unsigned int add_in = _hb_glyph_info_get_glyph_props (&buffer->cur()) &

 			  HB_OT_LAYOUT_GLYPH_PROPS_PRESERVE;

     add_in |= HB_OT_LAYOUT_GLYPH_PROPS_SUBSTITUTED;

     if (ligature)

       add_in |= HB_OT_LAYOUT_GLYPH_PROPS_LIGATED;

     if (likely (has_glyph_classes))

       _hb_glyph_info_set_glyph_props (&buffer->cur(), add_in | gdef.get_glyph_props (glyph_index));

     else if (class_guess)

       _hb_glyph_info_set_glyph_props (&buffer->cur(), add_in | class_guess);

   }

   inline void replace_glyph (hb_codepoint_t glyph_index) const

   {

     _set_glyph_props (glyph_index);

     buffer->replace_glyph (glyph_index);

   }

   inline void replace_glyph_inplace (hb_codepoint_t glyph_index) const

   {

     _set_glyph_props (glyph_index);

     buffer->cur().codepoint = glyph_index;

   }

   inline void replace_glyph_with_ligature (hb_codepoint_t glyph_index,

 					   unsigned int class_guess) const

   {

     _set_glyph_props (glyph_index, class_guess, true);

     buffer->replace_glyph (glyph_index);

   }

   inline void output_glyph (hb_codepoint_t glyph_index,

 			    unsigned int class_guess) const

   {

     _set_glyph_props (glyph_index, class_guess);

     buffer->output_glyph (glyph_index);

   }

 };

 typedef bool (*intersects_func_t) (hb_set_t *glyphs, const USHORT &value, const void *data);

 typedef void (*collect_glyphs_func_t) (hb_set_t *glyphs, const USHORT &value, const void *data);

 typedef bool (*match_func_t) (hb_codepoint_t glyph_id, const USHORT &value, const void *data);

 struct ContextClosureFuncs

 {

   intersects_func_t intersects;

 };

 struct ContextCollectGlyphsFuncs

 {

   collect_glyphs_func_t collect;

 };

 struct ContextApplyFuncs

 {

   match_func_t match;

 };

 static inline bool intersects_glyph (hb_set_t *glyphs, const USHORT &value, const void *data HB_UNUSED)

 {

   return glyphs->has (value);

 }

 static inline bool intersects_class (hb_set_t *glyphs, const USHORT &value, const void *data)

 {

   const ClassDef &class_def = *reinterpret_cast<const ClassDef *>(data);

   return class_def.intersects_class (glyphs, value);

 }

 static inline bool intersects_coverage (hb_set_t *glyphs, const USHORT &value, const void *data)

 {

   const OffsetTo<Coverage> &coverage = (const OffsetTo<Coverage>&)value;

   return (data+coverage).intersects (glyphs);

 }

 static inline bool intersects_array (hb_closure_context_t *c,

 				     unsigned int count,

 				     const USHORT values[],

 				     intersects_func_t intersects_func,

 				     const void *intersects_data)

 {

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

     if (likely (!intersects_func (c->glyphs, values[i], intersects_data)))

       return false;

   return true;

 }

 static inline void collect_glyph (hb_set_t *glyphs, const USHORT &value, const void *data HB_UNUSED)

 {

   glyphs->add (value);

 }

 static inline void collect_class (hb_set_t *glyphs, const USHORT &value, const void *data)

 {

   const ClassDef &class_def = *reinterpret_cast<const ClassDef *>(data);

   class_def.add_class (glyphs, value);

 }

 static inline void collect_coverage (hb_set_t *glyphs, const USHORT &value, const void *data)

 {

   const OffsetTo<Coverage> &coverage = (const OffsetTo<Coverage>&)value;

   (data+coverage).add_coverage (glyphs);

 }

 static inline void collect_array (hb_collect_glyphs_context_t *c HB_UNUSED,

 				  hb_set_t *glyphs,

 				  unsigned int count,

 				  const USHORT values[],

 				  collect_glyphs_func_t collect_func,

 				  const void *collect_data)

 {

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

     collect_func (glyphs, values[i], collect_data);

 }

 static inline bool match_glyph (hb_codepoint_t glyph_id, const USHORT &value, const void *data HB_UNUSED)

 {

   return glyph_id == value;

 }

 static inline bool match_class (hb_codepoint_t glyph_id, const USHORT &value, const void *data)

 {

   const ClassDef &class_def = *reinterpret_cast<const ClassDef *>(data);

   return class_def.get_class (glyph_id) == value;

 }

 static inline bool match_coverage (hb_codepoint_t glyph_id, const USHORT &value, const void *data)

 {

   const OffsetTo<Coverage> &coverage = (const OffsetTo<Coverage>&)value;

   return (data+coverage).get_coverage (glyph_id) != NOT_COVERED;

 }

 static inline bool would_match_input (hb_would_apply_context_t *c,

 				      unsigned int count, /* Including the first glyph (not matched) */

 				      const USHORT input[], /* Array of input values--start with second glyph */

 				      match_func_t match_func,

 				      const void *match_data)

 {

   if (count != c->len)

     return false;

   for (unsigned int i = 1; i < count; i++)

     if (likely (!match_func (c->glyphs[i], input[i - 1], match_data)))

       return false;

   return true;

 }

 static inline bool match_input (hb_apply_context_t *c,

 				unsigned int count, /* Including the first glyph (not matched) */

 				const USHORT input[], /* Array of input values--start with second glyph */

 				match_func_t match_func,

 				const void *match_data,

 				unsigned int *end_offset,

 				unsigned int match_positions[MAX_CONTEXT_LENGTH],

 				bool *p_is_mark_ligature = NULL,

 				unsigned int *p_total_component_count = NULL)

 {

   TRACE_APPLY (NULL);

   if (unlikely (count > MAX_CONTEXT_LENGTH)) TRACE_RETURN (false);

   hb_buffer_t *buffer = c->buffer;

   hb_apply_context_t::skipping_forward_iterator_t skippy_iter (c, buffer->idx, count - 1);

   skippy_iter.set_match_func (match_func, match_data, input);

   if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);

   /*

    * This is perhaps the trickiest part of OpenType...  Remarks:

    *

    * - If all components of the ligature were marks, we call this a mark ligature.

    *

    * - If there is no GDEF, and the ligature is NOT a mark ligature, we categorize

    *   it as a ligature glyph.

    *

    * - Ligatures cannot be formed across glyphs attached to different components

    *   of previous ligatures.  Eg. the sequence is LAM,SHADDA,LAM,FATHA,HEH, and

    *   LAM,LAM,HEH form a ligature, leaving SHADDA,FATHA next to eachother.

    *   However, it would be wrong to ligate that SHADDA,FATHA sequence.o

    *   There is an exception to this: If a ligature tries ligating with marks that

    *   belong to it itself, go ahead, assuming that the font designer knows what

    *   they are doing (otherwise it can break Indic stuff when a matra wants to

    *   ligate with a conjunct...)

    */

   bool is_mark_ligature = _hb_glyph_info_is_mark (&buffer->cur());

   unsigned int total_component_count = 0;

   total_component_count += _hb_glyph_info_get_lig_num_comps (&buffer->cur());

   unsigned int first_lig_id = _hb_glyph_info_get_lig_id (&buffer->cur());

   unsigned int first_lig_comp = _hb_glyph_info_get_lig_comp (&buffer->cur());

   match_positions[0] = buffer->idx;

   for (unsigned int i = 1; i < count; i++)

   {

     if (!skippy_iter.next ()) return TRACE_RETURN (false);

     match_positions[i] = skippy_iter.idx;

     unsigned int this_lig_id = _hb_glyph_info_get_lig_id (&buffer->info[skippy_iter.idx]);

     unsigned int this_lig_comp = _hb_glyph_info_get_lig_comp (&buffer->info[skippy_iter.idx]);

     if (first_lig_id && first_lig_comp) {

       /* If first component was attached to a previous ligature component,

        * all subsequent components should be attached to the same ligature

        * component, otherwise we shouldn't ligate them. */

       if (first_lig_id != this_lig_id || first_lig_comp != this_lig_comp)

 	return TRACE_RETURN (false);

     } else {

       /* If first component was NOT attached to a previous ligature component,

        * all subsequent components should also NOT be attached to any ligature

        * component, unless they are attached to the first component itself! */

       if (this_lig_id && this_lig_comp && (this_lig_id != first_lig_id))

 	return TRACE_RETURN (false);

     }

     is_mark_ligature = is_mark_ligature && _hb_glyph_info_is_mark (&buffer->info[skippy_iter.idx]);

     total_component_count += _hb_glyph_info_get_lig_num_comps (&buffer->info[skippy_iter.idx]);

   }

   *end_offset = skippy_iter.idx - buffer->idx + 1;

   if (p_is_mark_ligature)

     *p_is_mark_ligature = is_mark_ligature;

   if (p_total_component_count)

     *p_total_component_count = total_component_count;

   return TRACE_RETURN (true);

 }

 static inline void ligate_input (hb_apply_context_t *c,

 				 unsigned int count, /* Including the first glyph */

 				 unsigned int match_positions[MAX_CONTEXT_LENGTH], /* Including the first glyph */

 				 unsigned int match_length,

 				 hb_codepoint_t lig_glyph,

 				 bool is_mark_ligature,

 				 unsigned int total_component_count)

 {

   TRACE_APPLY (NULL);

   hb_buffer_t *buffer = c->buffer;

   buffer->merge_clusters (buffer->idx, buffer->idx + match_length);

   /*

    * - If it *is* a mark ligature, we don't allocate a new ligature id, and leave

    *   the ligature to keep its old ligature id.  This will allow it to attach to

    *   a base ligature in GPOS.  Eg. if the sequence is: LAM,LAM,SHADDA,FATHA,HEH,

    *   and LAM,LAM,HEH for a ligature, they will leave SHADDA and FATHA wit a

    *   ligature id and component value of 2.  Then if SHADDA,FATHA form a ligature

    *   later, we don't want them to lose their ligature id/component, otherwise

    *   GPOS will fail to correctly position the mark ligature on top of the

    *   LAM,LAM,HEH ligature.  See:

    *     https://bugzilla.gnome.org/show_bug.cgi?id=676343

    *

    * - If a ligature is formed of components that some of which are also ligatures

    *   themselves, and those ligature components had marks attached to *their*

    *   components, we have to attach the marks to the new ligature component

    *   positions!  Now *that*'s tricky!  And these marks may be following the

    *   last component of the whole sequence, so we should loop forward looking

    *   for them and update them.

    *

    *   Eg. the sequence is LAM,LAM,SHADDA,FATHA,HEH, and the font first forms a

    *   'calt' ligature of LAM,HEH, leaving the SHADDA and FATHA with a ligature

    *   id and component == 1.  Now, during 'liga', the LAM and the LAM-HEH ligature

    *   form a LAM-LAM-HEH ligature.  We need to reassign the SHADDA and FATHA to

    *   the new ligature with a component value of 2.

    *

    *   This in fact happened to a font...  See:

    *   https://bugzilla.gnome.org/show_bug.cgi?id=437633

    */

   unsigned int klass = is_mark_ligature ? 0 : HB_OT_LAYOUT_GLYPH_PROPS_LIGATURE;

   unsigned int lig_id = is_mark_ligature ? 0 : _hb_allocate_lig_id (buffer);

   unsigned int last_lig_id = _hb_glyph_info_get_lig_id (&buffer->cur());

   unsigned int last_num_components = _hb_glyph_info_get_lig_num_comps (&buffer->cur());

   unsigned int components_so_far = last_num_components;

   if (!is_mark_ligature)

   {

     _hb_glyph_info_set_lig_props_for_ligature (&buffer->cur(), lig_id, total_component_count);

     if (_hb_glyph_info_get_general_category (&buffer->cur()) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)

     {

       _hb_glyph_info_set_general_category (&buffer->cur(), HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER);

       _hb_glyph_info_set_modified_combining_class (&buffer->cur(), 0);

     }

   }

   c->replace_glyph_with_ligature (lig_glyph, klass);

   for (unsigned int i = 1; i < count; i++)

   {

     while (buffer->idx < match_positions[i])

     {

       if (!is_mark_ligature) {

 	unsigned int new_lig_comp = components_so_far - last_num_components +

 				    MIN (MAX (_hb_glyph_info_get_lig_comp (&buffer->cur()), 1u), last_num_components);

 	_hb_glyph_info_set_lig_props_for_mark (&buffer->cur(), lig_id, new_lig_comp);

       }

       buffer->next_glyph ();

     }

     last_lig_id = _hb_glyph_info_get_lig_id (&buffer->cur());

     last_num_components = _hb_glyph_info_get_lig_num_comps (&buffer->cur());

     components_so_far += last_num_components;

     /* Skip the base glyph */

     buffer->idx++;

   }

   if (!is_mark_ligature && last_lig_id) {

     /* Re-adjust components for any marks following. */

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

       if (last_lig_id == _hb_glyph_info_get_lig_id (&buffer->info[i])) {

 	unsigned int new_lig_comp = components_so_far - last_num_components +

 				    MIN (MAX (_hb_glyph_info_get_lig_comp (&buffer->info[i]), 1u), last_num_components);

 	_hb_glyph_info_set_lig_props_for_mark (&buffer->info[i], lig_id, new_lig_comp);

       } else

 	break;

     }

   }

 }

 static inline bool match_backtrack (hb_apply_context_t *c,

 				    unsigned int count,

 				    const USHORT backtrack[],

 				    match_func_t match_func,

 				    const void *match_data)

 {

   TRACE_APPLY (NULL);

   hb_apply_context_t::skipping_backward_iterator_t skippy_iter (c, c->buffer->backtrack_len (), count, true);

   skippy_iter.set_match_func (match_func, match_data, backtrack);

   if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);

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

     if (!skippy_iter.prev ())

       return TRACE_RETURN (false);

   return TRACE_RETURN (true);

 }

 static inline bool match_lookahead (hb_apply_context_t *c,

 				    unsigned int count,

 				    const USHORT lookahead[],

 				    match_func_t match_func,

 				    const void *match_data,

 				    unsigned int offset)

 {

   TRACE_APPLY (NULL);

   hb_apply_context_t::skipping_forward_iterator_t skippy_iter (c, c->buffer->idx + offset - 1, count, true);

   skippy_iter.set_match_func (match_func, match_data, lookahead);

   if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);

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

     if (!skippy_iter.next ())

       return TRACE_RETURN (false);

   return TRACE_RETURN (true);

 }

 struct LookupRecord

 {

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (c->check_struct (this));

   }

   USHORT	sequenceIndex;		/* Index into current glyph

 					 * sequence--first glyph = 0 */

   USHORT	lookupListIndex;	/* Lookup to apply to that

 					 * position--zero--based */

   public:

   DEFINE_SIZE_STATIC (4);

 };

 template <typename context_t>

 static inline void recurse_lookups (context_t *c,

 				    unsigned int lookupCount,

 				    const LookupRecord lookupRecord[] /* Array of LookupRecords--in design order */)

 {

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

     c->recurse (lookupRecord[i].lookupListIndex);

 }

 static inline bool apply_lookup (hb_apply_context_t *c,

 				 unsigned int count, /* Including the first glyph */

 				 unsigned int match_positions[MAX_CONTEXT_LENGTH], /* Including the first glyph */

 				 unsigned int lookupCount,

 				 const LookupRecord lookupRecord[], /* Array of LookupRecords--in design order */

 				 unsigned int match_length)

 {

   TRACE_APPLY (NULL);

   hb_buffer_t *buffer = c->buffer;

   unsigned int end;

   /* All positions are distance from beginning of *output* buffer.

    * Adjust. */

   {

     unsigned int bl = buffer->backtrack_len ();

     end = bl + match_length;

     int delta = bl - buffer->idx;

     /* Convert positions to new indexing. */

     for (unsigned int j = 0; j < count; j++)

       match_positions[j] += delta;

   }

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

   {

     unsigned int idx = lookupRecord[i].sequenceIndex;

     if (idx >= count)

       continue;

     buffer->move_to (match_positions[idx]);

     unsigned int orig_len = buffer->backtrack_len () + buffer->lookahead_len ();

     if (!c->recurse (lookupRecord[i].lookupListIndex))

       continue;

     unsigned int new_len = buffer->backtrack_len () + buffer->lookahead_len ();

     int delta = new_len - orig_len;

     if (!delta)

         continue;

     /* Recursed lookup changed buffer len.  Adjust. */

     /* end can't go back past the current match position. */

     end = MAX ((int) match_positions[idx] + 1, int (end) + delta);

     unsigned int next = idx + 1; /* next now is the position after the recursed lookup. */

     if (delta > 0)

     {

       if (unlikely (delta + count > MAX_CONTEXT_LENGTH))

 	break;

     }

     else

     {

       /* NOTE: delta is negative. */

       delta = MAX (delta, (int) next - (int) count);

       next -= delta;

     }

     /* Shift! */

     memmove (match_positions + next + delta, match_positions + next,

 	     (count - next) * sizeof (match_positions[0]));

     next += delta;

     count += delta;

     /* Fill in new entries. */

     for (unsigned int j = idx + 1; j < next; j++)

       match_positions[j] = match_positions[j - 1] + 1;

     /* And fixup the rest. */

     for (; next < count; next++)

       match_positions[next] += delta;

   }

   buffer->move_to (end);

   return TRACE_RETURN (true);

 }

 /* Contextual lookups */

 struct ContextClosureLookupContext

 {

   ContextClosureFuncs funcs;

   const void *intersects_data;

 };

 struct ContextCollectGlyphsLookupContext

 {

   ContextCollectGlyphsFuncs funcs;

   const void *collect_data;

 };

 struct ContextApplyLookupContext

 {

   ContextApplyFuncs funcs;

   const void *match_data;

 };

 static inline void context_closure_lookup (hb_closure_context_t *c,

 					   unsigned int inputCount, /* Including the first glyph (not matched) */

 					   const USHORT input[], /* Array of input values--start with second glyph */

 					   unsigned int lookupCount,

 					   const LookupRecord lookupRecord[],

 					   ContextClosureLookupContext &lookup_context)

 {

   if (intersects_array (c,

 			inputCount ? inputCount - 1 : 0, input,

 			lookup_context.funcs.intersects, lookup_context.intersects_data))

     recurse_lookups (c,

 		     lookupCount, lookupRecord);

 }

 static inline void context_collect_glyphs_lookup (hb_collect_glyphs_context_t *c,

 						  unsigned int inputCount, /* Including the first glyph (not matched) */

 						  const USHORT input[], /* Array of input values--start with second glyph */

 						  unsigned int lookupCount,

 						  const LookupRecord lookupRecord[],

 						  ContextCollectGlyphsLookupContext &lookup_context)

 {

   collect_array (c, c->input,

 		 inputCount ? inputCount - 1 : 0, input,

 		 lookup_context.funcs.collect, lookup_context.collect_data);

   recurse_lookups (c,

 		   lookupCount, lookupRecord);

 }

 static inline bool context_would_apply_lookup (hb_would_apply_context_t *c,

 					       unsigned int inputCount, /* Including the first glyph (not matched) */

 					       const USHORT input[], /* Array of input values--start with second glyph */

 					       unsigned int lookupCount HB_UNUSED,

 					       const LookupRecord lookupRecord[] HB_UNUSED,

 					       ContextApplyLookupContext &lookup_context)

 {

   return would_match_input (c,

 			    inputCount, input,

 			    lookup_context.funcs.match, lookup_context.match_data);

 }

 static inline bool context_apply_lookup (hb_apply_context_t *c,

 					 unsigned int inputCount, /* Including the first glyph (not matched) */

 					 const USHORT input[], /* Array of input values--start with second glyph */

 					 unsigned int lookupCount,

 					 const LookupRecord lookupRecord[],

 					 ContextApplyLookupContext &lookup_context)

 {

   unsigned int match_length = 0;

   unsigned int match_positions[MAX_CONTEXT_LENGTH];

   return match_input (c,

 		      inputCount, input,

 		      lookup_context.funcs.match, lookup_context.match_data,

 		      &match_length, match_positions)

       && apply_lookup (c,

 		       inputCount, match_positions,

 		       lookupCount, lookupRecord,

 		       match_length);

 }

 struct Rule

 {

   inline void closure (hb_closure_context_t *c, ContextClosureLookupContext &lookup_context) const

   {

     TRACE_CLOSURE (this);

     const LookupRecord *lookupRecord = &StructAtOffset<LookupRecord> (input, input[0].static_size * (inputCount ? inputCount - 1 : 0));

     context_closure_lookup (c,

 			    inputCount, input,

 			    lookupCount, lookupRecord,

 			    lookup_context);

   }

   inline void collect_glyphs (hb_collect_glyphs_context_t *c, ContextCollectGlyphsLookupContext &lookup_context) const

   {

     TRACE_COLLECT_GLYPHS (this);

     const LookupRecord *lookupRecord = &StructAtOffset<LookupRecord> (input, input[0].static_size * (inputCount ? inputCount - 1 : 0));

     context_collect_glyphs_lookup (c,

 				   inputCount, input,

 				   lookupCount, lookupRecord,

 				   lookup_context);

   }

   inline bool would_apply (hb_would_apply_context_t *c, ContextApplyLookupContext &lookup_context) const

   {

     TRACE_WOULD_APPLY (this);

     const LookupRecord *lookupRecord = &StructAtOffset<LookupRecord> (input, input[0].static_size * (inputCount ? inputCount - 1 : 0));

     return TRACE_RETURN (context_would_apply_lookup (c, inputCount, input, lookupCount, lookupRecord, lookup_context));

   }

   inline bool apply (hb_apply_context_t *c, ContextApplyLookupContext &lookup_context) const

   {

     TRACE_APPLY (this);

     const LookupRecord *lookupRecord = &StructAtOffset<LookupRecord> (input, input[0].static_size * (inputCount ? inputCount - 1 : 0));

     return TRACE_RETURN (context_apply_lookup (c, inputCount, input, lookupCount, lookupRecord, lookup_context));

   }

   public:

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return inputCount.sanitize (c)

 	&& lookupCount.sanitize (c)

 	&& c->check_range (input,

 			   input[0].static_size * inputCount

 			   + lookupRecordX[0].static_size * lookupCount);

   }

   protected:

   USHORT	inputCount;		/* Total number of glyphs in input

 					 * glyph sequence--includes the first

 					 * glyph */

   USHORT	lookupCount;		/* Number of LookupRecords */

   USHORT	input[VAR];		/* Array of match inputs--start with

 					 * second glyph */

   LookupRecord	lookupRecordX[VAR];	/* Array of LookupRecords--in

 					 * design order */

   public:

   DEFINE_SIZE_ARRAY2 (4, input, lookupRecordX);

 };

 struct RuleSet

 {

   inline void closure (hb_closure_context_t *c, ContextClosureLookupContext &lookup_context) const

   {

     TRACE_CLOSURE (this);

     unsigned int num_rules = rule.len;

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

       (this+rule[i]).closure (c, lookup_context);

   }

   inline void collect_glyphs (hb_collect_glyphs_context_t *c, ContextCollectGlyphsLookupContext &lookup_context) const

   {

     TRACE_COLLECT_GLYPHS (this);

     unsigned int num_rules = rule.len;

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

       (this+rule[i]).collect_glyphs (c, lookup_context);

   }

   inline bool would_apply (hb_would_apply_context_t *c, ContextApplyLookupContext &lookup_context) const

   {

     TRACE_WOULD_APPLY (this);

     unsigned int num_rules = rule.len;

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

     {

       if ((this+rule[i]).would_apply (c, lookup_context))

         return TRACE_RETURN (true);

     }

     return TRACE_RETURN (false);

   }

   inline bool apply (hb_apply_context_t *c, ContextApplyLookupContext &lookup_context) const

   {

     TRACE_APPLY (this);

     unsigned int num_rules = rule.len;

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

     {

       if ((this+rule[i]).apply (c, lookup_context))

         return TRACE_RETURN (true);

     }

     return TRACE_RETURN (false);

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (rule.sanitize (c, this));

   }

   protected:

   OffsetArrayOf<Rule>

 		rule;			/* Array of Rule tables

 					 * ordered by preference */

   public:

   DEFINE_SIZE_ARRAY (2, rule);

 };

 struct ContextFormat1

 {

   inline void closure (hb_closure_context_t *c) const

   {

     TRACE_CLOSURE (this);

     const Coverage &cov = (this+coverage);

     struct ContextClosureLookupContext lookup_context = {

       {intersects_glyph},

       NULL

     };

     unsigned int count = ruleSet.len;

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

       if (cov.intersects_coverage (c->glyphs, i)) {

 	const RuleSet &rule_set = this+ruleSet[i];

 	rule_set.closure (c, lookup_context);

       }

   }

   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const

   {

     TRACE_COLLECT_GLYPHS (this);

     (this+coverage).add_coverage (c->input);

     struct ContextCollectGlyphsLookupContext lookup_context = {

       {collect_glyph},

       NULL

     };

     unsigned int count = ruleSet.len;

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

       (this+ruleSet[i]).collect_glyphs (c, lookup_context);

   }

   inline bool would_apply (hb_would_apply_context_t *c) const

   {

     TRACE_WOULD_APPLY (this);

     const RuleSet &rule_set = this+ruleSet[(this+coverage).get_coverage (c->glyphs[0])];

     struct ContextApplyLookupContext lookup_context = {

       {match_glyph},

       NULL

     };

     return TRACE_RETURN (rule_set.would_apply (c, lookup_context));

   }

   inline const Coverage &get_coverage (void) const

   {

     return this+coverage;

   }

   inline bool apply (hb_apply_context_t *c) const

   {

     TRACE_APPLY (this);

     unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);

     if (likely (index == NOT_COVERED))

       return TRACE_RETURN (false);

     const RuleSet &rule_set = this+ruleSet[index];

     struct ContextApplyLookupContext lookup_context = {

       {match_glyph},

       NULL

     };

     return TRACE_RETURN (rule_set.apply (c, lookup_context));

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (coverage.sanitize (c, this) && ruleSet.sanitize (c, this));

   }

   protected:

   USHORT	format;			/* Format identifier--format = 1 */

   OffsetTo<Coverage>

 		coverage;		/* Offset to Coverage table--from

 					 * beginning of table */

   OffsetArrayOf<RuleSet>

 		ruleSet;		/* Array of RuleSet tables

 					 * ordered by Coverage Index */

   public:

   DEFINE_SIZE_ARRAY (6, ruleSet);

 };

 struct ContextFormat2

 {

   inline void closure (hb_closure_context_t *c) const

   {

     TRACE_CLOSURE (this);

     if (!(this+coverage).intersects (c->glyphs))

       return;

     const ClassDef &class_def = this+classDef;

     struct ContextClosureLookupContext lookup_context = {

       {intersects_class},

       &class_def

     };

     unsigned int count = ruleSet.len;

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

       if (class_def.intersects_class (c->glyphs, i)) {

 	const RuleSet &rule_set = this+ruleSet[i];

 	rule_set.closure (c, lookup_context);

       }

   }

   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const

   {

     TRACE_COLLECT_GLYPHS (this);

     (this+coverage).add_coverage (c->input);

     const ClassDef &class_def = this+classDef;

     struct ContextCollectGlyphsLookupContext lookup_context = {

       {collect_class},

       &class_def

     };

     unsigned int count = ruleSet.len;

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

       (this+ruleSet[i]).collect_glyphs (c, lookup_context);

   }

   inline bool would_apply (hb_would_apply_context_t *c) const

   {

     TRACE_WOULD_APPLY (this);

     const ClassDef &class_def = this+classDef;

     unsigned int index = class_def.get_class (c->glyphs[0]);

     const RuleSet &rule_set = this+ruleSet[index];

     struct ContextApplyLookupContext lookup_context = {

       {match_class},

       &class_def

     };

     return TRACE_RETURN (rule_set.would_apply (c, lookup_context));

   }

   inline const Coverage &get_coverage (void) const

   {

     return this+coverage;

   }

   inline bool apply (hb_apply_context_t *c) const

   {

     TRACE_APPLY (this);

     unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);

     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);

     const ClassDef &class_def = this+classDef;

     index = class_def.get_class (c->buffer->cur().codepoint);

     const RuleSet &rule_set = this+ruleSet[index];

     struct ContextApplyLookupContext lookup_context = {

       {match_class},

       &class_def

     };

     return TRACE_RETURN (rule_set.apply (c, lookup_context));

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (coverage.sanitize (c, this) && classDef.sanitize (c, this) && ruleSet.sanitize (c, this));

   }

   protected:

   USHORT	format;			/* Format identifier--format = 2 */

   OffsetTo<Coverage>

 		coverage;		/* Offset to Coverage table--from

 					 * beginning of table */

   OffsetTo<ClassDef>

 		classDef;		/* Offset to glyph ClassDef table--from

 					 * beginning of table */

   OffsetArrayOf<RuleSet>

 		ruleSet;		/* Array of RuleSet tables

 					 * ordered by class */

   public:

   DEFINE_SIZE_ARRAY (8, ruleSet);

 };

 struct ContextFormat3

 {

   inline void closure (hb_closure_context_t *c) const

   {

     TRACE_CLOSURE (this);

     if (!(this+coverage[0]).intersects (c->glyphs))

       return;

     const LookupRecord *lookupRecord = &StructAtOffset<LookupRecord> (coverage, coverage[0].static_size * glyphCount);

     struct ContextClosureLookupContext lookup_context = {

       {intersects_coverage},

       this

     };

     context_closure_lookup (c,

 			    glyphCount, (const USHORT *) (coverage + 1),

 			    lookupCount, lookupRecord,

 			    lookup_context);

   }

   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const

   {

     TRACE_COLLECT_GLYPHS (this);

     (this+coverage[0]).add_coverage (c->input);

     const LookupRecord *lookupRecord = &StructAtOffset<LookupRecord> (coverage, coverage[0].static_size * glyphCount);

     struct ContextCollectGlyphsLookupContext lookup_context = {

       {collect_coverage},

       this

     };

     context_collect_glyphs_lookup (c,

 				   glyphCount, (const USHORT *) (coverage + 1),

 				   lookupCount, lookupRecord,

 				   lookup_context);

   }

   inline bool would_apply (hb_would_apply_context_t *c) const

   {

     TRACE_WOULD_APPLY (this);

     const LookupRecord *lookupRecord = &StructAtOffset<LookupRecord> (coverage, coverage[0].static_size * glyphCount);

     struct ContextApplyLookupContext lookup_context = {

       {match_coverage},

       this

     };

     return TRACE_RETURN (context_would_apply_lookup (c, glyphCount, (const USHORT *) (coverage + 1), lookupCount, lookupRecord, lookup_context));

   }

   inline const Coverage &get_coverage (void) const

   {

     return this+coverage[0];

   }

   inline bool apply (hb_apply_context_t *c) const

   {

     TRACE_APPLY (this);

     unsigned int index = (this+coverage[0]).get_coverage (c->buffer->cur().codepoint);

     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);

     const LookupRecord *lookupRecord = &StructAtOffset<LookupRecord> (coverage, coverage[0].static_size * glyphCount);

     struct ContextApplyLookupContext lookup_context = {

       {match_coverage},

       this

     };

     return TRACE_RETURN (context_apply_lookup (c, glyphCount, (const USHORT *) (coverage + 1), lookupCount, lookupRecord, lookup_context));

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     if (!c->check_struct (this)) return TRACE_RETURN (false);

     unsigned int count = glyphCount;

     if (!c->check_array (coverage, coverage[0].static_size, count)) return TRACE_RETURN (false);

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

       if (!coverage[i].sanitize (c, this)) return TRACE_RETURN (false);

     LookupRecord *lookupRecord = &StructAtOffset<LookupRecord> (coverage, coverage[0].static_size * count);

     return TRACE_RETURN (c->check_array (lookupRecord, lookupRecord[0].static_size, lookupCount));

   }

   protected:

   USHORT	format;			/* Format identifier--format = 3 */

   USHORT	glyphCount;		/* Number of glyphs in the input glyph

 					 * sequence */

   USHORT	lookupCount;		/* Number of LookupRecords */

   OffsetTo<Coverage>

 		coverage[VAR];		/* Array of offsets to Coverage

 					 * table in glyph sequence order */

   LookupRecord	lookupRecordX[VAR];	/* Array of LookupRecords--in

 					 * design order */

   public:

   DEFINE_SIZE_ARRAY2 (6, coverage, lookupRecordX);

 };

 struct Context

 {

   template <typename context_t>

   inline typename context_t::return_t dispatch (context_t *c) const

   {

     TRACE_DISPATCH (this);

     switch (u.format) {

     case 1: return TRACE_RETURN (c->dispatch (u.format1));

     case 2: return TRACE_RETURN (c->dispatch (u.format2));

     case 3: return TRACE_RETURN (c->dispatch (u.format3));

     default:return TRACE_RETURN (c->default_return_value ());

     }

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     if (!u.format.sanitize (c)) return TRACE_RETURN (false);

     switch (u.format) {

     case 1: return TRACE_RETURN (u.format1.sanitize (c));

     case 2: return TRACE_RETURN (u.format2.sanitize (c));

     case 3: return TRACE_RETURN (u.format3.sanitize (c));

     default:return TRACE_RETURN (true);

     }

   }

   protected:

   union {

   USHORT		format;		/* Format identifier */

   ContextFormat1	format1;

   ContextFormat2	format2;

   ContextFormat3	format3;

   } u;

 };

 /* Chaining Contextual lookups */

 struct ChainContextClosureLookupContext

 {

   ContextClosureFuncs funcs;

   const void *intersects_data[3];

 };

 struct ChainContextCollectGlyphsLookupContext

 {

   ContextCollectGlyphsFuncs funcs;

   const void *collect_data[3];

 };

 struct ChainContextApplyLookupContext

 {

   ContextApplyFuncs funcs;

   const void *match_data[3];

 };

 static inline void chain_context_closure_lookup (hb_closure_context_t *c,

 						 unsigned int backtrackCount,

 						 const USHORT backtrack[],

 						 unsigned int inputCount, /* Including the first glyph (not matched) */

 						 const USHORT input[], /* Array of input values--start with second glyph */

 						 unsigned int lookaheadCount,

 						 const USHORT lookahead[],

 						 unsigned int lookupCount,

 						 const LookupRecord lookupRecord[],

 						 ChainContextClosureLookupContext &lookup_context)

 {

   if (intersects_array (c,

 			backtrackCount, backtrack,

 			lookup_context.funcs.intersects, lookup_context.intersects_data[0])

    && intersects_array (c,

 			inputCount ? inputCount - 1 : 0, input,

 			lookup_context.funcs.intersects, lookup_context.intersects_data[1])

    && intersects_array (c,

 		       lookaheadCount, lookahead,

 		       lookup_context.funcs.intersects, lookup_context.intersects_data[2]))

     recurse_lookups (c,

 		     lookupCount, lookupRecord);

 }

 static inline void chain_context_collect_glyphs_lookup (hb_collect_glyphs_context_t *c,

 						        unsigned int backtrackCount,

 						        const USHORT backtrack[],

 						        unsigned int inputCount, /* Including the first glyph (not matched) */

 						        const USHORT input[], /* Array of input values--start with second glyph */

 						        unsigned int lookaheadCount,

 						        const USHORT lookahead[],

 						        unsigned int lookupCount,

 						        const LookupRecord lookupRecord[],

 						        ChainContextCollectGlyphsLookupContext &lookup_context)

 {

   collect_array (c, c->before,

 		 backtrackCount, backtrack,

 		 lookup_context.funcs.collect, lookup_context.collect_data[0]);

   collect_array (c, c->input,

 		 inputCount ? inputCount - 1 : 0, input,

 		 lookup_context.funcs.collect, lookup_context.collect_data[1]);

   collect_array (c, c->after,

 		 lookaheadCount, lookahead,

 		 lookup_context.funcs.collect, lookup_context.collect_data[2]);

   recurse_lookups (c,

 		   lookupCount, lookupRecord);

 }

 static inline bool chain_context_would_apply_lookup (hb_would_apply_context_t *c,

 						     unsigned int backtrackCount,

 						     const USHORT backtrack[] HB_UNUSED,

 						     unsigned int inputCount, /* Including the first glyph (not matched) */

 						     const USHORT input[], /* Array of input values--start with second glyph */

 						     unsigned int lookaheadCount,

 						     const USHORT lookahead[] HB_UNUSED,

 						     unsigned int lookupCount HB_UNUSED,

 						     const LookupRecord lookupRecord[] HB_UNUSED,

 						     ChainContextApplyLookupContext &lookup_context)

 {

   return (c->zero_context ? !backtrackCount && !lookaheadCount : true)

       && would_match_input (c,

 			    inputCount, input,

 			    lookup_context.funcs.match, lookup_context.match_data[1]);

 }

 static inline bool chain_context_apply_lookup (hb_apply_context_t *c,

 					       unsigned int backtrackCount,

 					       const USHORT backtrack[],

 					       unsigned int inputCount, /* Including the first glyph (not matched) */

 					       const USHORT input[], /* Array of input values--start with second glyph */

 					       unsigned int lookaheadCount,

 					       const USHORT lookahead[],

 					       unsigned int lookupCount,

 					       const LookupRecord lookupRecord[],

 					       ChainContextApplyLookupContext &lookup_context)

 {

   unsigned int match_length = 0;

   unsigned int match_positions[MAX_CONTEXT_LENGTH];

   return match_input (c,

 		      inputCount, input,

 		      lookup_context.funcs.match, lookup_context.match_data[1],

 		      &match_length, match_positions)

       && match_backtrack (c,

 			  backtrackCount, backtrack,

 			  lookup_context.funcs.match, lookup_context.match_data[0])

       && match_lookahead (c,

 			  lookaheadCount, lookahead,

 			  lookup_context.funcs.match, lookup_context.match_data[2],

 			  match_length)

       && apply_lookup (c,

 		       inputCount, match_positions,

 		       lookupCount, lookupRecord,

 		       match_length);

 }

 struct ChainRule

 {

   inline void closure (hb_closure_context_t *c, ChainContextClosureLookupContext &lookup_context) const

   {

     TRACE_CLOSURE (this);

     const HeadlessArrayOf<USHORT> &input = StructAfter<HeadlessArrayOf<USHORT> > (backtrack);

     const ArrayOf<USHORT> &lookahead = StructAfter<ArrayOf<USHORT> > (input);

     const ArrayOf<LookupRecord> &lookup = StructAfter<ArrayOf<LookupRecord> > (lookahead);

     chain_context_closure_lookup (c,

 				  backtrack.len, backtrack.array,

 				  input.len, input.array,

 				  lookahead.len, lookahead.array,

 				  lookup.len, lookup.array,

 				  lookup_context);

   }

   inline void collect_glyphs (hb_collect_glyphs_context_t *c, ChainContextCollectGlyphsLookupContext &lookup_context) const

   {

     TRACE_COLLECT_GLYPHS (this);

     const HeadlessArrayOf<USHORT> &input = StructAfter<HeadlessArrayOf<USHORT> > (backtrack);

     const ArrayOf<USHORT> &lookahead = StructAfter<ArrayOf<USHORT> > (input);

     const ArrayOf<LookupRecord> &lookup = StructAfter<ArrayOf<LookupRecord> > (lookahead);

     chain_context_collect_glyphs_lookup (c,

 					 backtrack.len, backtrack.array,

 					 input.len, input.array,

 					 lookahead.len, lookahead.array,

 					 lookup.len, lookup.array,

 					 lookup_context);

   }

   inline bool would_apply (hb_would_apply_context_t *c, ChainContextApplyLookupContext &lookup_context) const

   {

     TRACE_WOULD_APPLY (this);

     const HeadlessArrayOf<USHORT> &input = StructAfter<HeadlessArrayOf<USHORT> > (backtrack);

     const ArrayOf<USHORT> &lookahead = StructAfter<ArrayOf<USHORT> > (input);

     const ArrayOf<LookupRecord> &lookup = StructAfter<ArrayOf<LookupRecord> > (lookahead);

     return TRACE_RETURN (chain_context_would_apply_lookup (c,

 							   backtrack.len, backtrack.array,

 							   input.len, input.array,

 							   lookahead.len, lookahead.array, lookup.len,

 							   lookup.array, lookup_context));

   }

   inline bool apply (hb_apply_context_t *c, ChainContextApplyLookupContext &lookup_context) const

   {

     TRACE_APPLY (this);

     const HeadlessArrayOf<USHORT> &input = StructAfter<HeadlessArrayOf<USHORT> > (backtrack);

     const ArrayOf<USHORT> &lookahead = StructAfter<ArrayOf<USHORT> > (input);

     const ArrayOf<LookupRecord> &lookup = StructAfter<ArrayOf<LookupRecord> > (lookahead);

     return TRACE_RETURN (chain_context_apply_lookup (c,

 						     backtrack.len, backtrack.array,

 						     input.len, input.array,

 						     lookahead.len, lookahead.array, lookup.len,

 						     lookup.array, lookup_context));

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     if (!backtrack.sanitize (c)) return TRACE_RETURN (false);

     HeadlessArrayOf<USHORT> &input = StructAfter<HeadlessArrayOf<USHORT> > (backtrack);

     if (!input.sanitize (c)) return TRACE_RETURN (false);

     ArrayOf<USHORT> &lookahead = StructAfter<ArrayOf<USHORT> > (input);

     if (!lookahead.sanitize (c)) return TRACE_RETURN (false);

     ArrayOf<LookupRecord> &lookup = StructAfter<ArrayOf<LookupRecord> > (lookahead);

     return TRACE_RETURN (lookup.sanitize (c));

   }

   protected:

   ArrayOf<USHORT>

 		backtrack;		/* Array of backtracking values

 					 * (to be matched before the input

 					 * sequence) */

   HeadlessArrayOf<USHORT>

 		inputX;			/* Array of input values (start with

 					 * second glyph) */

   ArrayOf<USHORT>

 		lookaheadX;		/* Array of lookahead values's (to be

 					 * matched after the input sequence) */

   ArrayOf<LookupRecord>

 		lookupX;		/* Array of LookupRecords--in

 					 * design order) */

   public:

   DEFINE_SIZE_MIN (8);

 };

 struct ChainRuleSet

 {

   inline void closure (hb_closure_context_t *c, ChainContextClosureLookupContext &lookup_context) const

   {

     TRACE_CLOSURE (this);

     unsigned int num_rules = rule.len;

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

       (this+rule[i]).closure (c, lookup_context);

   }

   inline void collect_glyphs (hb_collect_glyphs_context_t *c, ChainContextCollectGlyphsLookupContext &lookup_context) const

   {

     TRACE_COLLECT_GLYPHS (this);

     unsigned int num_rules = rule.len;

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

       (this+rule[i]).collect_glyphs (c, lookup_context);

   }

   inline bool would_apply (hb_would_apply_context_t *c, ChainContextApplyLookupContext &lookup_context) const

   {

     TRACE_WOULD_APPLY (this);

     unsigned int num_rules = rule.len;

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

       if ((this+rule[i]).would_apply (c, lookup_context))

         return TRACE_RETURN (true);

     return TRACE_RETURN (false);

   }

   inline bool apply (hb_apply_context_t *c, ChainContextApplyLookupContext &lookup_context) const

   {

     TRACE_APPLY (this);

     unsigned int num_rules = rule.len;

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

       if ((this+rule[i]).apply (c, lookup_context))

         return TRACE_RETURN (true);

     return TRACE_RETURN (false);

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (rule.sanitize (c, this));

   }

   protected:

   OffsetArrayOf<ChainRule>

 		rule;			/* Array of ChainRule tables

 					 * ordered by preference */

   public:

   DEFINE_SIZE_ARRAY (2, rule);

 };

 struct ChainContextFormat1

 {

   inline void closure (hb_closure_context_t *c) const

   {

     TRACE_CLOSURE (this);

     const Coverage &cov = (this+coverage);

     struct ChainContextClosureLookupContext lookup_context = {

       {intersects_glyph},

       {NULL, NULL, NULL}

     };

     unsigned int count = ruleSet.len;

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

       if (cov.intersects_coverage (c->glyphs, i)) {

 	const ChainRuleSet &rule_set = this+ruleSet[i];

 	rule_set.closure (c, lookup_context);

       }

   }

   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const

   {

     TRACE_COLLECT_GLYPHS (this);

     (this+coverage).add_coverage (c->input);

     struct ChainContextCollectGlyphsLookupContext lookup_context = {

       {collect_glyph},

       {NULL, NULL, NULL}

     };

     unsigned int count = ruleSet.len;

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

       (this+ruleSet[i]).collect_glyphs (c, lookup_context);

   }

   inline bool would_apply (hb_would_apply_context_t *c) const

   {

     TRACE_WOULD_APPLY (this);

     const ChainRuleSet &rule_set = this+ruleSet[(this+coverage).get_coverage (c->glyphs[0])];

     struct ChainContextApplyLookupContext lookup_context = {

       {match_glyph},

       {NULL, NULL, NULL}

     };

     return TRACE_RETURN (rule_set.would_apply (c, lookup_context));

   }

   inline const Coverage &get_coverage (void) const

   {

     return this+coverage;

   }

   inline bool apply (hb_apply_context_t *c) const

   {

     TRACE_APPLY (this);

     unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);

     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);

     const ChainRuleSet &rule_set = this+ruleSet[index];

     struct ChainContextApplyLookupContext lookup_context = {

       {match_glyph},

       {NULL, NULL, NULL}

     };

     return TRACE_RETURN (rule_set.apply (c, lookup_context));

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (coverage.sanitize (c, this) && ruleSet.sanitize (c, this));

   }

   protected:

   USHORT	format;			/* Format identifier--format = 1 */

   OffsetTo<Coverage>

 		coverage;		/* Offset to Coverage table--from

 					 * beginning of table */

   OffsetArrayOf<ChainRuleSet>

 		ruleSet;		/* Array of ChainRuleSet tables

 					 * ordered by Coverage Index */

   public:

   DEFINE_SIZE_ARRAY (6, ruleSet);

 };

 struct ChainContextFormat2

 {

   inline void closure (hb_closure_context_t *c) const

   {

     TRACE_CLOSURE (this);

     if (!(this+coverage).intersects (c->glyphs))

       return;

     const ClassDef &backtrack_class_def = this+backtrackClassDef;

     const ClassDef &input_class_def = this+inputClassDef;

     const ClassDef &lookahead_class_def = this+lookaheadClassDef;

     struct ChainContextClosureLookupContext lookup_context = {

       {intersects_class},

       {&backtrack_class_def,

        &input_class_def,

        &lookahead_class_def}

     };

     unsigned int count = ruleSet.len;

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

       if (input_class_def.intersects_class (c->glyphs, i)) {

 	const ChainRuleSet &rule_set = this+ruleSet[i];

 	rule_set.closure (c, lookup_context);

       }

   }

   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const

   {

     TRACE_COLLECT_GLYPHS (this);

     (this+coverage).add_coverage (c->input);

     const ClassDef &backtrack_class_def = this+backtrackClassDef;

     const ClassDef &input_class_def = this+inputClassDef;

     const ClassDef &lookahead_class_def = this+lookaheadClassDef;

     struct ChainContextCollectGlyphsLookupContext lookup_context = {

       {collect_class},

       {&backtrack_class_def,

        &input_class_def,

        &lookahead_class_def}

     };

     unsigned int count = ruleSet.len;

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

       (this+ruleSet[i]).collect_glyphs (c, lookup_context);

   }

   inline bool would_apply (hb_would_apply_context_t *c) const

   {

     TRACE_WOULD_APPLY (this);

     const ClassDef &backtrack_class_def = this+backtrackClassDef;

     const ClassDef &input_class_def = this+inputClassDef;

     const ClassDef &lookahead_class_def = this+lookaheadClassDef;

     unsigned int index = input_class_def.get_class (c->glyphs[0]);

     const ChainRuleSet &rule_set = this+ruleSet[index];

     struct ChainContextApplyLookupContext lookup_context = {

       {match_class},

       {&backtrack_class_def,

        &input_class_def,

        &lookahead_class_def}

     };

     return TRACE_RETURN (rule_set.would_apply (c, lookup_context));

   }

   inline const Coverage &get_coverage (void) const

   {

     return this+coverage;

   }

   inline bool apply (hb_apply_context_t *c) const

   {

     TRACE_APPLY (this);

     unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);

     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);

     const ClassDef &backtrack_class_def = this+backtrackClassDef;

     const ClassDef &input_class_def = this+inputClassDef;

     const ClassDef &lookahead_class_def = this+lookaheadClassDef;

     index = input_class_def.get_class (c->buffer->cur().codepoint);

     const ChainRuleSet &rule_set = this+ruleSet[index];

     struct ChainContextApplyLookupContext lookup_context = {

       {match_class},

       {&backtrack_class_def,

        &input_class_def,

        &lookahead_class_def}

     };

     return TRACE_RETURN (rule_set.apply (c, lookup_context));

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (coverage.sanitize (c, this) && backtrackClassDef.sanitize (c, this) &&

 			 inputClassDef.sanitize (c, this) && lookaheadClassDef.sanitize (c, this) &&

 			 ruleSet.sanitize (c, this));

   }

   protected:

   USHORT	format;			/* Format identifier--format = 2 */

   OffsetTo<Coverage>

 		coverage;		/* Offset to Coverage table--from

 					 * beginning of table */

   OffsetTo<ClassDef>

 		backtrackClassDef;	/* Offset to glyph ClassDef table

 					 * containing backtrack sequence

 					 * data--from beginning of table */

   OffsetTo<ClassDef>

 		inputClassDef;		/* Offset to glyph ClassDef

 					 * table containing input sequence

 					 * data--from beginning of table */

   OffsetTo<ClassDef>

 		lookaheadClassDef;	/* Offset to glyph ClassDef table

 					 * containing lookahead sequence

 					 * data--from beginning of table */

   OffsetArrayOf<ChainRuleSet>

 		ruleSet;		/* Array of ChainRuleSet tables

 					 * ordered by class */

   public:

   DEFINE_SIZE_ARRAY (12, ruleSet);

 };

 struct ChainContextFormat3

 {

   inline void closure (hb_closure_context_t *c) const

   {

     TRACE_CLOSURE (this);

     const OffsetArrayOf<Coverage> &input = StructAfter<OffsetArrayOf<Coverage> > (backtrack);

     if (!(this+input[0]).intersects (c->glyphs))

       return;

     const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (input);

     const ArrayOf<LookupRecord> &lookup = StructAfter<ArrayOf<LookupRecord> > (lookahead);

     struct ChainContextClosureLookupContext lookup_context = {

       {intersects_coverage},

       {this, this, this}

     };

     chain_context_closure_lookup (c,

 				  backtrack.len, (const USHORT *) backtrack.array,

 				  input.len, (const USHORT *) input.array + 1,

 				  lookahead.len, (const USHORT *) lookahead.array,

 				  lookup.len, lookup.array,

 				  lookup_context);

   }

   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const

   {

     TRACE_COLLECT_GLYPHS (this);

     const OffsetArrayOf<Coverage> &input = StructAfter<OffsetArrayOf<Coverage> > (backtrack);

     (this+input[0]).add_coverage (c->input);

     const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (input);

     const ArrayOf<LookupRecord> &lookup = StructAfter<ArrayOf<LookupRecord> > (lookahead);

     struct ChainContextCollectGlyphsLookupContext lookup_context = {

       {collect_coverage},

       {this, this, this}

     };

     chain_context_collect_glyphs_lookup (c,

 					 backtrack.len, (const USHORT *) backtrack.array,

 					 input.len, (const USHORT *) input.array + 1,

 					 lookahead.len, (const USHORT *) lookahead.array,

 					 lookup.len, lookup.array,

 					 lookup_context);

   }

   inline bool would_apply (hb_would_apply_context_t *c) const

   {

     TRACE_WOULD_APPLY (this);

     const OffsetArrayOf<Coverage> &input = StructAfter<OffsetArrayOf<Coverage> > (backtrack);

     const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (input);

     const ArrayOf<LookupRecord> &lookup = StructAfter<ArrayOf<LookupRecord> > (lookahead);

     struct ChainContextApplyLookupContext lookup_context = {

       {match_coverage},

       {this, this, this}

     };

     return TRACE_RETURN (chain_context_would_apply_lookup (c,

 							   backtrack.len, (const USHORT *) backtrack.array,

 							   input.len, (const USHORT *) input.array + 1,

 							   lookahead.len, (const USHORT *) lookahead.array,

 							   lookup.len, lookup.array, lookup_context));

   }

   inline const Coverage &get_coverage (void) const

   {

     const OffsetArrayOf<Coverage> &input = StructAfter<OffsetArrayOf<Coverage> > (backtrack);

     return this+input[0];

   }

   inline bool apply (hb_apply_context_t *c) const

   {

     TRACE_APPLY (this);

     const OffsetArrayOf<Coverage> &input = StructAfter<OffsetArrayOf<Coverage> > (backtrack);

     unsigned int index = (this+input[0]).get_coverage (c->buffer->cur().codepoint);

     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);

     const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (input);

     const ArrayOf<LookupRecord> &lookup = StructAfter<ArrayOf<LookupRecord> > (lookahead);

     struct ChainContextApplyLookupContext lookup_context = {

       {match_coverage},

       {this, this, this}

     };

     return TRACE_RETURN (chain_context_apply_lookup (c,

 						     backtrack.len, (const USHORT *) backtrack.array,

 						     input.len, (const USHORT *) input.array + 1,

 						     lookahead.len, (const USHORT *) lookahead.array,

 						     lookup.len, lookup.array, lookup_context));

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     if (!backtrack.sanitize (c, this)) return TRACE_RETURN (false);

     OffsetArrayOf<Coverage> &input = StructAfter<OffsetArrayOf<Coverage> > (backtrack);

     if (!input.sanitize (c, this)) return TRACE_RETURN (false);

     OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (input);

     if (!lookahead.sanitize (c, this)) return TRACE_RETURN (false);

     ArrayOf<LookupRecord> &lookup = StructAfter<ArrayOf<LookupRecord> > (lookahead);

     return TRACE_RETURN (lookup.sanitize (c));

   }

   protected:

   USHORT	format;			/* Format identifier--format = 3 */

   OffsetArrayOf<Coverage>

 		backtrack;		/* Array of coverage tables

 					 * in backtracking sequence, in  glyph

 					 * sequence order */

   OffsetArrayOf<Coverage>

 		inputX		;	/* Array of coverage

 					 * tables in input sequence, in glyph

 					 * sequence order */

   OffsetArrayOf<Coverage>

 		lookaheadX;		/* Array of coverage tables

 					 * in lookahead sequence, in glyph

 					 * sequence order */

   ArrayOf<LookupRecord>

 		lookupX;		/* Array of LookupRecords--in

 					 * design order) */

   public:

   DEFINE_SIZE_MIN (10);

 };

 struct ChainContext

 {

   template <typename context_t>

   inline typename context_t::return_t dispatch (context_t *c) const

   {

     TRACE_DISPATCH (this);

     switch (u.format) {

     case 1: return TRACE_RETURN (c->dispatch (u.format1));

     case 2: return TRACE_RETURN (c->dispatch (u.format2));

     case 3: return TRACE_RETURN (c->dispatch (u.format3));

     default:return TRACE_RETURN (c->default_return_value ());

     }

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     if (!u.format.sanitize (c)) return TRACE_RETURN (false);

     switch (u.format) {

     case 1: return TRACE_RETURN (u.format1.sanitize (c));

     case 2: return TRACE_RETURN (u.format2.sanitize (c));

     case 3: return TRACE_RETURN (u.format3.sanitize (c));

     default:return TRACE_RETURN (true);

     }

   }

   protected:

   union {

   USHORT		format;	/* Format identifier */

   ChainContextFormat1	format1;

   ChainContextFormat2	format2;

   ChainContextFormat3	format3;

   } u;

 };

 struct ExtensionFormat1

 {

   inline unsigned int get_type (void) const { return extensionLookupType; }

   inline unsigned int get_offset (void) const { return extensionOffset; }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (c->check_struct (this));

   }

   protected:

   USHORT	format;			/* Format identifier. Set to 1. */

   USHORT	extensionLookupType;	/* Lookup type of subtable referenced

 					 * by ExtensionOffset (i.e. the

 					 * extension subtable). */

   ULONG		extensionOffset;	/* Offset to the extension subtable,

 					 * of lookup type subtable. */

   public:

   DEFINE_SIZE_STATIC (8);

 };

 template <typename T>

 struct Extension

 {

   inline unsigned int get_type (void) const

   {

     switch (u.format) {

     case 1: return u.format1.get_type ();

     default:return 0;

     }

   }

   inline unsigned int get_offset (void) const

   {

     switch (u.format) {

     case 1: return u.format1.get_offset ();

     default:return 0;

     }

   }

   template <typename X>

   inline const X& get_subtable (void) const

   {

     unsigned int offset = get_offset ();

     if (unlikely (!offset)) return Null(typename T::LookupSubTable);

     return StructAtOffset<typename T::LookupSubTable> (this, offset);

   }

   template <typename context_t>

   inline typename context_t::return_t dispatch (context_t *c) const

   {

     return get_subtable<typename T::LookupSubTable> ().dispatch (c, get_type ());

   }

   inline bool sanitize_self (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     if (!u.format.sanitize (c)) return TRACE_RETURN (false);

     switch (u.format) {

     case 1: return TRACE_RETURN (u.format1.sanitize (c));

     default:return TRACE_RETURN (true);

     }

   }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     if (!sanitize_self (c)) return TRACE_RETURN (false);

     unsigned int offset = get_offset ();

     if (unlikely (!offset)) return TRACE_RETURN (true);

     return TRACE_RETURN (StructAtOffset<typename T::LookupSubTable> (this, offset).sanitize (c, get_type ()));

   }

   protected:

   union {

   USHORT		format;		/* Format identifier */

   ExtensionFormat1	format1;

   } u;

 };

 /*

  * GSUB/GPOS Common

  */

 struct GSUBGPOS

 {

   static const hb_tag_t GSUBTag	= HB_OT_TAG_GSUB;

   static const hb_tag_t GPOSTag	= HB_OT_TAG_GPOS;

   inline unsigned int get_script_count (void) const

   { return (this+scriptList).len; }

   inline const Tag& get_script_tag (unsigned int i) const

   { return (this+scriptList).get_tag (i); }

   inline unsigned int get_script_tags (unsigned int start_offset,

 				       unsigned int *script_count /* IN/OUT */,

 				       hb_tag_t     *script_tags /* OUT */) const

   { return (this+scriptList).get_tags (start_offset, script_count, script_tags); }

   inline const Script& get_script (unsigned int i) const

   { return (this+scriptList)[i]; }

   inline bool find_script_index (hb_tag_t tag, unsigned int *index) const

   { return (this+scriptList).find_index (tag, index); }

   inline unsigned int get_feature_count (void) const

   { return (this+featureList).len; }

   inline const Tag& get_feature_tag (unsigned int i) const

   { return (this+featureList).get_tag (i); }

   inline unsigned int get_feature_tags (unsigned int start_offset,

 					unsigned int *feature_count /* IN/OUT */,

 					hb_tag_t     *feature_tags /* OUT */) const

   { return (this+featureList).get_tags (start_offset, feature_count, feature_tags); }

   inline const Feature& get_feature (unsigned int i) const

   { return (this+featureList)[i]; }

   inline bool find_feature_index (hb_tag_t tag, unsigned int *index) const

   { return (this+featureList).find_index (tag, index); }

   inline unsigned int get_lookup_count (void) const

   { return (this+lookupList).len; }

   inline const Lookup& get_lookup (unsigned int i) const

   { return (this+lookupList)[i]; }

   inline bool sanitize (hb_sanitize_context_t *c) {

     TRACE_SANITIZE (this);

     return TRACE_RETURN (version.sanitize (c) && likely (version.major == 1) &&

 			 scriptList.sanitize (c, this) &&

 			 featureList.sanitize (c, this) &&

 			 lookupList.sanitize (c, this));

   }

   protected:

   FixedVersion	version;	/* Version of the GSUB/GPOS table--initially set

 				 * to 0x00010000 */

   OffsetTo<ScriptList>

 		scriptList;  	/* ScriptList table */

   OffsetTo<FeatureList>

 		featureList; 	/* FeatureList table */

   OffsetTo<LookupList>

 		lookupList; 	/* LookupList table */

   public:

   DEFINE_SIZE_STATIC (10);

 };

 } /* namespace OT */

 #endif /* HB_OT_LAYOUT_GSUBGPOS_PRIVATE_HH */