src/OT/Layout/GSUB/ReverseChainSingleSubstFormat1.hh - third_party/harfbuzz - Git at Google

 #ifndef OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH
 #define OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH

 #include "Common.hh"

 namespace OT {
 namespace Layout {
 namespace GSUB_impl {

 struct ReverseChainSingleSubstFormat1
 {
   protected:
   HBUINT16      format;                 /* Format identifier--format = 1 */
   Offset16To<Coverage>
                 coverage;               /* Offset to Coverage table--from
                                          * beginning of table */
   Array16OfOffset16To<Coverage>
                 backtrack;              /* Array of coverage tables
                                          * in backtracking sequence, in glyph
                                          * sequence order */
   Array16OfOffset16To<Coverage>
                 lookaheadX;             /* Array of coverage tables
                                          * in lookahead sequence, in glyph
                                          * sequence order */
   Array16Of<HBGlyphID16>
                 substituteX;            /* Array of substitute
                                          * GlyphIDs--ordered by Coverage Index */
   public:
   DEFINE_SIZE_MIN (10);

   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
     if (!(coverage.sanitize (c, this) && backtrack.sanitize (c, this)))
       return_trace (false);
     hb_barrier ();
     const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
     if (!lookahead.sanitize (c, this))
       return_trace (false);
     hb_barrier ();
     const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);
     return_trace (substitute.sanitize (c));
   }

   bool intersects (const hb_set_t *glyphs) const
   {
     if (!(this+coverage).intersects (glyphs))
       return false;

     const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);

     unsigned int count;

     count = backtrack.len;
     for (unsigned int i = 0; i < count; i++)
       if (!(this+backtrack[i]).intersects (glyphs))
         return false;

     count = lookahead.len;
     for (unsigned int i = 0; i < count; i++)
       if (!(this+lookahead[i]).intersects (glyphs))
         return false;

     return true;
   }

   bool may_have_non_1to1 () const
   { return false; }

   void depend (hb_depend_context_t *c) const {
     // Filter by intersects and parent_active_glyphs like closure does
     if (!intersects (c->glyphs)) return;

     const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
     const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);

     /* Build context set from backtrack and lookahead coverages.
      * ReverseChainSingleSubst has contextual requirements - the substitution
      * only fires when backtrack and lookahead glyphs are present. */
     hb_set_t context_glyphs;

     /* Add glyphs from backtrack coverages */
     unsigned int count = backtrack.len;
     for (unsigned int i = 0; i < count; i++)
     {
       hb_set_t back_glyphs;
       (this+backtrack[i]).intersect_set (*c->glyphs, back_glyphs);
       if (back_glyphs.get_population () == 1)
         context_glyphs.add (back_glyphs.get_min ());
       else if (back_glyphs.get_population () > 1)
       {
         hb_codepoint_t set_idx = c->depend_data->find_or_create_context_set (back_glyphs);
         if (unlikely (set_idx == HB_CODEPOINT_INVALID))
           return;
         context_glyphs.add (HB_DEPEND_CONTEXT_SET_FLAG | set_idx);
       }
     }

     /* Add glyphs from lookahead coverages */
     count = lookahead.len;
     for (unsigned int i = 0; i < count; i++)
     {
       hb_set_t look_glyphs;
       (this+lookahead[i]).intersect_set (*c->glyphs, look_glyphs);
       if (look_glyphs.get_population () == 1)
         context_glyphs.add (look_glyphs.get_min ());
       else if (look_glyphs.get_population () > 1)
       {
         hb_codepoint_t set_idx = c->depend_data->find_or_create_context_set (look_glyphs);
         if (unlikely (set_idx == HB_CODEPOINT_INVALID))
           return;
         context_glyphs.add (HB_DEPEND_CONTEXT_SET_FLAG | set_idx);
       }
     }

     /* Allocate context set and save/restore around edge creation */
     if (unlikely (context_glyphs.in_error ()))
     {
       c->depend_data->fail ();
       return;
     }
     hb_codepoint_t context_set_idx = context_glyphs.is_empty ()
       ? HB_CODEPOINT_INVALID
       : c->depend_data->find_or_create_context_set (context_glyphs);
     if (unlikely (!context_glyphs.is_empty () &&
                   context_set_idx == HB_CODEPOINT_INVALID))
       return;

     hb_codepoint_t saved_context = c->depend_data->current_context_set_index;
     c->depend_data->current_context_set_index = context_set_idx;

     + hb_zip (this+coverage, substitute)
     | hb_filter (c->parent_active_glyphs (), hb_first)
     | hb_apply ([&] (const hb_codepoint_pair_t &_) { c->depend_data->add_gsub_lookup (_.first, c->lookup_index, _.second); })
     ;

     c->depend_data->current_context_set_index = saved_context;
   }

   void closure (hb_closure_context_t *c) const
   {
     if (!intersects (c->glyphs)) return;

     const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
     const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);

     + hb_zip (this+coverage, substitute)
     | hb_filter (c->parent_active_glyphs (), hb_first)
     | hb_map (hb_second)
     | hb_sink (c->output)
     ;
   }

   void closure_lookups (hb_closure_lookups_context_t *c) const {}

   void collect_glyphs (hb_collect_glyphs_context_t *c) const
   {
     if (unlikely (!(this+coverage).collect_coverage (c->input))) return;

     unsigned int count;

     count = backtrack.len;
     for (unsigned int i = 0; i < count; i++)
       if (unlikely (!(this+backtrack[i]).collect_coverage (c->before))) return;

     const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
     count = lookahead.len;
     for (unsigned int i = 0; i < count; i++)
       if (unlikely (!(this+lookahead[i]).collect_coverage (c->after))) return;

     const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);
     count = substitute.len;
     c->output->add_array (substitute.arrayZ, substitute.len);
   }

   const Coverage &get_coverage () const { return this+coverage; }

   bool would_apply (hb_would_apply_context_t *c) const
   { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }

   bool apply (hb_ot_apply_context_t *c) const
   {
     TRACE_APPLY (this);
     unsigned int index = (this+coverage).get_coverage (c->buffer->cur ().codepoint);
     if (index == NOT_COVERED) return_trace (false);

     if (unlikely (c->nesting_level_left != HB_MAX_NESTING_LEVEL))
       return_trace (false); /* No chaining to this type */

     const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
     const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);

     if (unlikely (index >= substitute.len)) return_trace (false);

     unsigned int start_index = 0, end_index = 0;
     if (match_backtrack (c,
                          backtrack.len, (HBUINT16 *) backtrack.arrayZ,
                          match_coverage, this,
                          &start_index) &&
         match_lookahead (c,
                          lookahead.len, (HBUINT16 *) lookahead.arrayZ,
                          match_coverage, this,
                          c->buffer->idx + 1, &end_index))
     {
       c->buffer->unsafe_to_break_from_outbuffer (start_index, end_index);

       if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
       {
 	c->buffer->message (c->font,
 			    "replacing glyph at %u (reverse chaining substitution)",
 			    c->buffer->idx);
       }

       c->replace_glyph_inplace (substitute[index]);

       if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
       {
 	c->buffer->message (c->font,
 			    "replaced glyph at %u (reverse chaining substitution)",
 			    c->buffer->idx);
       }

       /* Note: We DON'T decrease buffer->idx.  The main loop does it
        * for us.  This is useful for preventing surprises if someone
        * calls us through a Context lookup. */
       return_trace (true);
     }
     else
     {
       c->buffer->unsafe_to_concat_from_outbuffer (start_index, end_index);
       return_trace (false);
     }
   }

   template<typename Iterator,
            hb_requires (hb_is_iterator (Iterator))>
   bool serialize_coverage_offset_array (hb_subset_context_t *c, Iterator it) const
   {
     TRACE_SERIALIZE (this);
     auto *out = c->serializer->start_embed<Array16OfOffset16To<Coverage>> ();

     if (unlikely (!c->serializer->allocate_size<HBUINT16> (HBUINT16::static_size)))
       return_trace (false);

     for (auto& offset : it) {
       auto *o = out->serialize_append (c->serializer);
       if (unlikely (!o) || !o->serialize_subset (c, offset, this))
         return_trace (false);
     }

     return_trace (true);
   }

   template<typename Iterator, typename BacktrackIterator, typename LookaheadIterator,
            hb_requires (hb_is_sorted_source_of (Iterator, hb_codepoint_pair_t)),
            hb_requires (hb_is_iterator (BacktrackIterator)),
            hb_requires (hb_is_iterator (LookaheadIterator))>
   bool serialize (hb_subset_context_t *c,
                   Iterator coverage_subst_iter,
                   BacktrackIterator backtrack_iter,
                   LookaheadIterator lookahead_iter) const
   {
     TRACE_SERIALIZE (this);

     auto *out = c->serializer->start_embed (this);
     if (unlikely (!c->serializer->embed (this->format))) return_trace (false);
     if (unlikely (!c->serializer->embed (this->coverage))) return_trace (false);

     if (!serialize_coverage_offset_array (c, backtrack_iter)) return_trace (false);
     if (!serialize_coverage_offset_array (c, lookahead_iter)) return_trace (false);

     auto *substitute_out = c->serializer->start_embed<Array16Of<HBGlyphID16>> ();
     auto substitutes =
     + coverage_subst_iter
     | hb_map (hb_second)
     ;

     auto glyphs =
     + coverage_subst_iter
     | hb_map_retains_sorting (hb_first)
     ;
     if (unlikely (! c->serializer->check_success (substitute_out->serialize (c->serializer, substitutes))))
         return_trace (false);

     if (unlikely (!out->coverage.serialize_serialize (c->serializer, glyphs)))
       return_trace (false);
     return_trace (true);
   }

   bool subset (hb_subset_context_t *c) const
   {
     TRACE_SUBSET (this);
     const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
     const hb_map_t &glyph_map = *c->plan->glyph_map;

     const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
     const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);

     auto it =
     + hb_zip (this+coverage, substitute)
     | hb_filter (glyphset, hb_first)
     | hb_filter (glyphset, hb_second)
     | hb_map_retains_sorting ([&] (hb_pair_t<hb_codepoint_t, const HBGlyphID16 &> p) -> hb_codepoint_pair_t
                               { return hb_pair (glyph_map[p.first], glyph_map[p.second]); })
     ;

     return_trace (bool (it) && serialize (c, it, backtrack.iter (), lookahead.iter ()));
   }
 };

 }
 }
 }

 #endif  /* HB_OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH */
	#ifndef OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH
	#define OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH

	#include "Common.hh"

	namespace OT {
	namespace Layout {
	namespace GSUB_impl {

	struct ReverseChainSingleSubstFormat1
	{
	protected:
	HBUINT16 format; /* Format identifier--format = 1 */
	Offset16To<Coverage>
	coverage; /* Offset to Coverage table--from
	* beginning of table */
	Array16OfOffset16To<Coverage>
	backtrack; /* Array of coverage tables
	* in backtracking sequence, in glyph
	* sequence order */
	Array16OfOffset16To<Coverage>
	lookaheadX; /* Array of coverage tables
	* in lookahead sequence, in glyph
	* sequence order */
	Array16Of<HBGlyphID16>
	substituteX; /* Array of substitute
	* GlyphIDs--ordered by Coverage Index */
	public:
	DEFINE_SIZE_MIN (10);

	bool sanitize (hb_sanitize_context_t *c) const
	{
	TRACE_SANITIZE (this);
	if (!(coverage.sanitize (c, this) && backtrack.sanitize (c, this)))
	return_trace (false);
	hb_barrier ();
	const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
	if (!lookahead.sanitize (c, this))
	return_trace (false);
	hb_barrier ();
	const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);
	return_trace (substitute.sanitize (c));
	}

	bool intersects (const hb_set_t *glyphs) const
	{
	if (!(this+coverage).intersects (glyphs))
	return false;

	const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);

	unsigned int count;

	count = backtrack.len;
	for (unsigned int i = 0; i < count; i++)
	if (!(this+backtrack[i]).intersects (glyphs))
	return false;

	count = lookahead.len;
	for (unsigned int i = 0; i < count; i++)
	if (!(this+lookahead[i]).intersects (glyphs))
	return false;

	return true;
	}

	bool may_have_non_1to1 () const
	{ return false; }

	void depend (hb_depend_context_t *c) const {
	// Filter by intersects and parent_active_glyphs like closure does
	if (!intersects (c->glyphs)) return;

	const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
	const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);

	/* Build context set from backtrack and lookahead coverages.
	* ReverseChainSingleSubst has contextual requirements - the substitution
	* only fires when backtrack and lookahead glyphs are present. */
	hb_set_t context_glyphs;

	/* Add glyphs from backtrack coverages */
	unsigned int count = backtrack.len;
	for (unsigned int i = 0; i < count; i++)
	{
	hb_set_t back_glyphs;
	(this+backtrack[i]).intersect_set (*c->glyphs, back_glyphs);
	if (back_glyphs.get_population () == 1)
	context_glyphs.add (back_glyphs.get_min ());
	else if (back_glyphs.get_population () > 1)
	{
	hb_codepoint_t set_idx = c->depend_data->find_or_create_context_set (back_glyphs);
	if (unlikely (set_idx == HB_CODEPOINT_INVALID))
	return;
	context_glyphs.add (HB_DEPEND_CONTEXT_SET_FLAG \| set_idx);
	}
	}

	/* Add glyphs from lookahead coverages */
	count = lookahead.len;
	for (unsigned int i = 0; i < count; i++)
	{
	hb_set_t look_glyphs;
	(this+lookahead[i]).intersect_set (*c->glyphs, look_glyphs);
	if (look_glyphs.get_population () == 1)
	context_glyphs.add (look_glyphs.get_min ());
	else if (look_glyphs.get_population () > 1)
	{
	hb_codepoint_t set_idx = c->depend_data->find_or_create_context_set (look_glyphs);
	if (unlikely (set_idx == HB_CODEPOINT_INVALID))
	return;
	context_glyphs.add (HB_DEPEND_CONTEXT_SET_FLAG \| set_idx);
	}
	}

	/* Allocate context set and save/restore around edge creation */
	if (unlikely (context_glyphs.in_error ()))
	{
	c->depend_data->fail ();
	return;
	}
	hb_codepoint_t context_set_idx = context_glyphs.is_empty ()
	? HB_CODEPOINT_INVALID
	: c->depend_data->find_or_create_context_set (context_glyphs);
	if (unlikely (!context_glyphs.is_empty () &&
	context_set_idx == HB_CODEPOINT_INVALID))
	return;

	hb_codepoint_t saved_context = c->depend_data->current_context_set_index;
	c->depend_data->current_context_set_index = context_set_idx;

	+ hb_zip (this+coverage, substitute)
	\| hb_filter (c->parent_active_glyphs (), hb_first)
	\| hb_apply ([&] (const hb_codepoint_pair_t &_) { c->depend_data->add_gsub_lookup (_.first, c->lookup_index, _.second); })
	;

	c->depend_data->current_context_set_index = saved_context;
	}

	void closure (hb_closure_context_t *c) const
	{
	if (!intersects (c->glyphs)) return;

	const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
	const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);

	+ hb_zip (this+coverage, substitute)
	\| hb_filter (c->parent_active_glyphs (), hb_first)
	\| hb_map (hb_second)
	\| hb_sink (c->output)
	;
	}

	void closure_lookups (hb_closure_lookups_context_t *c) const {}

	void collect_glyphs (hb_collect_glyphs_context_t *c) const
	{
	if (unlikely (!(this+coverage).collect_coverage (c->input))) return;

	unsigned int count;

	count = backtrack.len;
	for (unsigned int i = 0; i < count; i++)
	if (unlikely (!(this+backtrack[i]).collect_coverage (c->before))) return;

	const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
	count = lookahead.len;
	for (unsigned int i = 0; i < count; i++)
	if (unlikely (!(this+lookahead[i]).collect_coverage (c->after))) return;

	const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);
	count = substitute.len;
	c->output->add_array (substitute.arrayZ, substitute.len);
	}

	const Coverage &get_coverage () const { return this+coverage; }

	bool would_apply (hb_would_apply_context_t *c) const
	{ return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }

	bool apply (hb_ot_apply_context_t *c) const
	{
	TRACE_APPLY (this);
	unsigned int index = (this+coverage).get_coverage (c->buffer->cur ().codepoint);
	if (index == NOT_COVERED) return_trace (false);

	if (unlikely (c->nesting_level_left != HB_MAX_NESTING_LEVEL))
	return_trace (false); /* No chaining to this type */

	const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
	const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);

	if (unlikely (index >= substitute.len)) return_trace (false);

	unsigned int start_index = 0, end_index = 0;
	if (match_backtrack (c,
	backtrack.len, (HBUINT16 *) backtrack.arrayZ,
	match_coverage, this,
	&start_index) &&
	match_lookahead (c,
	lookahead.len, (HBUINT16 *) lookahead.arrayZ,
	match_coverage, this,
	c->buffer->idx + 1, &end_index))
	{
	c->buffer->unsafe_to_break_from_outbuffer (start_index, end_index);

	if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
	{
	c->buffer->message (c->font,
	"replacing glyph at %u (reverse chaining substitution)",
	c->buffer->idx);
	}

	c->replace_glyph_inplace (substitute[index]);

	if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
	{
	c->buffer->message (c->font,
	"replaced glyph at %u (reverse chaining substitution)",
	c->buffer->idx);
	}

	/* Note: We DON'T decrease buffer->idx. The main loop does it
	* for us. This is useful for preventing surprises if someone
	* calls us through a Context lookup. */
	return_trace (true);
	}
	else
	{
	c->buffer->unsafe_to_concat_from_outbuffer (start_index, end_index);
	return_trace (false);
	}
	}

	template<typename Iterator,
	hb_requires (hb_is_iterator (Iterator))>
	bool serialize_coverage_offset_array (hb_subset_context_t *c, Iterator it) const
	{
	TRACE_SERIALIZE (this);
	auto *out = c->serializer->start_embed<Array16OfOffset16To<Coverage>> ();

	if (unlikely (!c->serializer->allocate_size<HBUINT16> (HBUINT16::static_size)))
	return_trace (false);

	for (auto& offset : it) {
	auto *o = out->serialize_append (c->serializer);
	if (unlikely (!o) \|\| !o->serialize_subset (c, offset, this))
	return_trace (false);
	}

	return_trace (true);
	}

	template<typename Iterator, typename BacktrackIterator, typename LookaheadIterator,
	hb_requires (hb_is_sorted_source_of (Iterator, hb_codepoint_pair_t)),
	hb_requires (hb_is_iterator (BacktrackIterator)),
	hb_requires (hb_is_iterator (LookaheadIterator))>
	bool serialize (hb_subset_context_t *c,
	Iterator coverage_subst_iter,
	BacktrackIterator backtrack_iter,
	LookaheadIterator lookahead_iter) const
	{
	TRACE_SERIALIZE (this);

	auto *out = c->serializer->start_embed (this);
	if (unlikely (!c->serializer->embed (this->format))) return_trace (false);
	if (unlikely (!c->serializer->embed (this->coverage))) return_trace (false);

	if (!serialize_coverage_offset_array (c, backtrack_iter)) return_trace (false);
	if (!serialize_coverage_offset_array (c, lookahead_iter)) return_trace (false);

	auto *substitute_out = c->serializer->start_embed<Array16Of<HBGlyphID16>> ();
	auto substitutes =
	+ coverage_subst_iter
	\| hb_map (hb_second)
	;

	auto glyphs =
	+ coverage_subst_iter
	\| hb_map_retains_sorting (hb_first)
	;
	if (unlikely (! c->serializer->check_success (substitute_out->serialize (c->serializer, substitutes))))
	return_trace (false);

	if (unlikely (!out->coverage.serialize_serialize (c->serializer, glyphs)))
	return_trace (false);
	return_trace (true);
	}

	bool subset (hb_subset_context_t *c) const
	{
	TRACE_SUBSET (this);
	const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
	const hb_map_t &glyph_map = *c->plan->glyph_map;

	const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
	const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);

	auto it =
	+ hb_zip (this+coverage, substitute)
	\| hb_filter (glyphset, hb_first)
	\| hb_filter (glyphset, hb_second)
	\| hb_map_retains_sorting ([&] (hb_pair_t<hb_codepoint_t, const HBGlyphID16 &> p) -> hb_codepoint_pair_t
	{ return hb_pair (glyph_map[p.first], glyph_map[p.second]); })
	;

	return_trace (bool (it) && serialize (c, it, backtrack.iter (), lookahead.iter ()));
	}
	};

	}
	}
	}

	#endif /* HB_OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH */