src/hb-subset-plan.cc - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2018  Google, Inc.
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
  * Permission is hereby granted, without written agreement and without
  * license or royalty fees, to use, copy, modify, and distribute this
  * software and its documentation for any purpose, provided that the
  * above copyright notice and the following two paragraphs appear in
  * all copies of this software.
  *
  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  *
  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * Google Author(s): Garret Rieger, Roderick Sheeter
  */

 #include "hb-subset-plan.hh"
 #include "hb-map.hh"
 #include "hb-set.hh"

 #include "hb-ot-cmap-table.hh"
 #include "hb-ot-glyf-table.hh"
 #include "hb-ot-cff1-table.hh"

 static inline void
 _add_gid_and_children (const OT::glyf::accelerator_t &glyf,
 		       hb_codepoint_t gid,
 		       hb_set_t *gids_to_retain)
 {
   if (hb_set_has (gids_to_retain, gid))
     // Already visited this gid, ignore.
     return;

   hb_set_add (gids_to_retain, gid);

   OT::glyf::CompositeGlyphHeader::Iterator composite;
   if (glyf.get_composite (gid, &composite))
   {
     do
     {
       _add_gid_and_children (glyf, (hb_codepoint_t) composite.current->glyphIndex, gids_to_retain);
     } while (composite.move_to_next());
   }
 }

 #ifndef HB_NO_SUBSET_CFF
 static inline void
 _add_cff_seac_components (const OT::cff1::accelerator_t &cff,
            hb_codepoint_t gid,
            hb_set_t *gids_to_retain)
 {
   hb_codepoint_t base_gid, accent_gid;
   if (cff.get_seac_components (gid, &base_gid, &accent_gid))
   {
     hb_set_add (gids_to_retain, base_gid);
     hb_set_add (gids_to_retain, accent_gid);
   }
 }
 #endif

 static inline void
 _gsub_closure (hb_face_t *face, hb_set_t *gids_to_retain)
 {
   hb_set_t lookup_indices;
   hb_ot_layout_collect_lookups (face,
 				HB_OT_TAG_GSUB,
 				nullptr,
 				nullptr,
 				nullptr,
 				&lookup_indices);
   hb_ot_layout_lookups_substitute_closure (face,
 					   &lookup_indices,
 					   gids_to_retain);
 }

 static inline void
 _remove_invalid_gids (hb_set_t *glyphs,
 		      unsigned int num_glyphs)
 {
   hb_codepoint_t gid = HB_SET_VALUE_INVALID;
   while (glyphs->next (&gid))
   {
     if (gid >= num_glyphs)
       glyphs->del (gid);
   }
 }

 static hb_set_t *
 _populate_gids_to_retain (hb_face_t *face,
 			  const hb_set_t *unicodes,
                           const hb_set_t *input_glyphs_to_retain,
 			  bool close_over_gsub,
 			  hb_set_t *unicodes_to_retain,
 			  hb_map_t *codepoint_to_glyph)
 {
   OT::cmap::accelerator_t cmap;
   OT::glyf::accelerator_t glyf;
   OT::cff1::accelerator_t cff;
   cmap.init (face);
   glyf.init (face);
   cff.init (face);

   hb_set_t *initial_gids_to_retain = hb_set_create ();
   initial_gids_to_retain->add (0); // Not-def
   hb_set_union (initial_gids_to_retain, input_glyphs_to_retain);

   hb_codepoint_t cp = HB_SET_VALUE_INVALID;
   while (unicodes->next (&cp))
   {
     hb_codepoint_t gid;
     if (!cmap.get_nominal_glyph (cp, &gid))
     {
       DEBUG_MSG(SUBSET, nullptr, "Drop U+%04X; no gid", cp);
       continue;
     }
     unicodes_to_retain->add (cp);
     codepoint_to_glyph->set (cp, gid);
     initial_gids_to_retain->add (gid);
   }

 #ifndef HB_NO_SUBSET_LAYOUT
   if (close_over_gsub)
     // Add all glyphs needed for GSUB substitutions.
     _gsub_closure (face, initial_gids_to_retain);
 #endif

   // Populate a full set of glyphs to retain by adding all referenced
   // composite glyphs.
   hb_codepoint_t gid = HB_SET_VALUE_INVALID;
   hb_set_t *all_gids_to_retain = hb_set_create ();
   while (initial_gids_to_retain->next (&gid))
   {
     _add_gid_and_children (glyf, gid, all_gids_to_retain);
 #ifndef HB_NO_SUBSET_CFF
     if (cff.is_valid ())
       _add_cff_seac_components (cff, gid, all_gids_to_retain);
 #endif
   }
   hb_set_destroy (initial_gids_to_retain);

   _remove_invalid_gids (all_gids_to_retain, face->get_num_glyphs ());

   cff.fini ();
   glyf.fini ();
   cmap.fini ();

   return all_gids_to_retain;
 }

 static void
 _create_old_gid_to_new_gid_map (const hb_face_t *face,
                                 bool             retain_gids,
 				const hb_set_t  *all_gids_to_retain,
                                 hb_map_t        *glyph_map, /* OUT */
                                 hb_map_t        *reverse_glyph_map, /* OUT */
                                 unsigned int    *num_glyphs /* OUT */)
 {
   if (!retain_gids)
   {
     + hb_enumerate (hb_iter (all_gids_to_retain), (hb_codepoint_t) 0)
     | hb_sink (reverse_glyph_map)
     ;
     *num_glyphs = reverse_glyph_map->get_population ();
   } else {
     + hb_iter (all_gids_to_retain)
     | hb_map ([=] (hb_codepoint_t _) {
 		return hb_pair_t<hb_codepoint_t, hb_codepoint_t> (_, _);
 	      })
     | hb_sink (reverse_glyph_map)
     ;

     // TODO(grieger): Should we discard glyphs past the max glyph to keep?
     // *num_glyphs = + hb_iter (all_gids_to_retain) | hb_reduce (hb_max, 0);
     *num_glyphs = face->get_num_glyphs ();
   }

   + reverse_glyph_map->iter ()
   | hb_map (&hb_pair_t<hb_codepoint_t, hb_codepoint_t>::reverse)
   | hb_sink (glyph_map)
   ;
 }

 /**
  * hb_subset_plan_create:
  * Computes a plan for subsetting the supplied face according
  * to a provided input. The plan describes
  * which tables and glyphs should be retained.
  *
  * Return value: New subset plan.
  *
  * Since: 1.7.5
  **/
 hb_subset_plan_t *
 hb_subset_plan_create (hb_face_t           *face,
 		       hb_subset_input_t   *input)
 {
   hb_subset_plan_t *plan = hb_object_create<hb_subset_plan_t> ();

   plan->drop_hints = input->drop_hints;
   plan->drop_layout = input->drop_layout;
   plan->desubroutinize = input->desubroutinize;
   plan->retain_gids = input->retain_gids;
   plan->unicodes = hb_set_create ();
   plan->name_ids = hb_set_reference (input->name_ids);
   /* TODO Clean this up... */
   if (hb_set_is_empty (plan->name_ids))
     hb_set_add_range (plan->name_ids, 0, 0x7FFF);
   plan->source = hb_face_reference (face);
   plan->dest = hb_face_builder_create ();
   plan->codepoint_to_glyph = hb_map_create ();
   plan->glyph_map = hb_map_create ();
   plan->reverse_glyph_map = hb_map_create ();
   plan->_glyphset = _populate_gids_to_retain (face,
                                               input->unicodes,
                                               input->glyphs,
                                               !plan->drop_layout,
                                               plan->unicodes,
                                               plan->codepoint_to_glyph);

   _create_old_gid_to_new_gid_map (face,
                                   input->retain_gids,
 				  plan->_glyphset,
 				  plan->glyph_map,
                                   plan->reverse_glyph_map,
                                   &plan->_num_output_glyphs);

   return plan;
 }

 /**
  * hb_subset_plan_destroy:
  *
  * Since: 1.7.5
  **/
 void
 hb_subset_plan_destroy (hb_subset_plan_t *plan)
 {
   if (!hb_object_destroy (plan)) return;

   hb_set_destroy (plan->unicodes);
   hb_set_destroy (plan->name_ids);
   hb_face_destroy (plan->source);
   hb_face_destroy (plan->dest);
   hb_map_destroy (plan->codepoint_to_glyph);
   hb_map_destroy (plan->glyph_map);
   hb_map_destroy (plan->reverse_glyph_map);
   hb_set_destroy (plan->_glyphset);

   free (plan);
 }
	/*
	* Copyright © 2018 Google, Inc.
	*
	* This is part of HarfBuzz, a text shaping library.
	*
	* Permission is hereby granted, without written agreement and without
	* license or royalty fees, to use, copy, modify, and distribute this
	* software and its documentation for any purpose, provided that the
	* above copyright notice and the following two paragraphs appear in
	* all copies of this software.
	*
	* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
	* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
	* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
	* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
	* DAMAGE.
	*
	* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
	* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
	* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
	* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
	* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
	*
	* Google Author(s): Garret Rieger, Roderick Sheeter
	*/

	#include "hb-subset-plan.hh"
	#include "hb-map.hh"
	#include "hb-set.hh"

	#include "hb-ot-cmap-table.hh"
	#include "hb-ot-glyf-table.hh"
	#include "hb-ot-cff1-table.hh"

	static inline void
	_add_gid_and_children (const OT::glyf::accelerator_t &glyf,
	hb_codepoint_t gid,
	hb_set_t *gids_to_retain)
	{
	if (hb_set_has (gids_to_retain, gid))
	// Already visited this gid, ignore.
	return;

	hb_set_add (gids_to_retain, gid);

	OT::glyf::CompositeGlyphHeader::Iterator composite;
	if (glyf.get_composite (gid, &composite))
	{
	do
	{
	_add_gid_and_children (glyf, (hb_codepoint_t) composite.current->glyphIndex, gids_to_retain);
	} while (composite.move_to_next());
	}
	}

	#ifndef HB_NO_SUBSET_CFF
	static inline void
	_add_cff_seac_components (const OT::cff1::accelerator_t &cff,
	hb_codepoint_t gid,
	hb_set_t *gids_to_retain)
	{
	hb_codepoint_t base_gid, accent_gid;
	if (cff.get_seac_components (gid, &base_gid, &accent_gid))
	{
	hb_set_add (gids_to_retain, base_gid);
	hb_set_add (gids_to_retain, accent_gid);
	}
	}
	#endif

	static inline void
	_gsub_closure (hb_face_t face, hb_set_t gids_to_retain)
	{
	hb_set_t lookup_indices;
	hb_ot_layout_collect_lookups (face,
	HB_OT_TAG_GSUB,
	nullptr,
	nullptr,
	nullptr,
	&lookup_indices);
	hb_ot_layout_lookups_substitute_closure (face,
	&lookup_indices,
	gids_to_retain);
	}

	static inline void
	_remove_invalid_gids (hb_set_t *glyphs,
	unsigned int num_glyphs)
	{
	hb_codepoint_t gid = HB_SET_VALUE_INVALID;
	while (glyphs->next (&gid))
	{
	if (gid >= num_glyphs)
	glyphs->del (gid);
	}
	}

	static hb_set_t *
	_populate_gids_to_retain (hb_face_t *face,
	const hb_set_t *unicodes,
	const hb_set_t *input_glyphs_to_retain,
	bool close_over_gsub,
	hb_set_t *unicodes_to_retain,
	hb_map_t *codepoint_to_glyph)
	{
	OT::cmap::accelerator_t cmap;
	OT::glyf::accelerator_t glyf;
	OT::cff1::accelerator_t cff;
	cmap.init (face);
	glyf.init (face);
	cff.init (face);

	hb_set_t *initial_gids_to_retain = hb_set_create ();
	initial_gids_to_retain->add (0); // Not-def
	hb_set_union (initial_gids_to_retain, input_glyphs_to_retain);

	hb_codepoint_t cp = HB_SET_VALUE_INVALID;
	while (unicodes->next (&cp))
	{
	hb_codepoint_t gid;
	if (!cmap.get_nominal_glyph (cp, &gid))
	{
	DEBUG_MSG(SUBSET, nullptr, "Drop U+%04X; no gid", cp);
	continue;
	}
	unicodes_to_retain->add (cp);
	codepoint_to_glyph->set (cp, gid);
	initial_gids_to_retain->add (gid);
	}

	#ifndef HB_NO_SUBSET_LAYOUT
	if (close_over_gsub)
	// Add all glyphs needed for GSUB substitutions.
	_gsub_closure (face, initial_gids_to_retain);
	#endif

	// Populate a full set of glyphs to retain by adding all referenced
	// composite glyphs.
	hb_codepoint_t gid = HB_SET_VALUE_INVALID;
	hb_set_t *all_gids_to_retain = hb_set_create ();
	while (initial_gids_to_retain->next (&gid))
	{
	_add_gid_and_children (glyf, gid, all_gids_to_retain);
	#ifndef HB_NO_SUBSET_CFF
	if (cff.is_valid ())
	_add_cff_seac_components (cff, gid, all_gids_to_retain);
	#endif
	}
	hb_set_destroy (initial_gids_to_retain);

	_remove_invalid_gids (all_gids_to_retain, face->get_num_glyphs ());

	cff.fini ();
	glyf.fini ();
	cmap.fini ();

	return all_gids_to_retain;
	}

	static void
	_create_old_gid_to_new_gid_map (const hb_face_t *face,
	bool retain_gids,
	const hb_set_t *all_gids_to_retain,
	hb_map_t glyph_map, / OUT */
	hb_map_t reverse_glyph_map, / OUT */
	unsigned int num_glyphs / OUT */)
	{
	if (!retain_gids)
	{
	+ hb_enumerate (hb_iter (all_gids_to_retain), (hb_codepoint_t) 0)
	\| hb_sink (reverse_glyph_map)
	;
	*num_glyphs = reverse_glyph_map->get_population ();
	} else {
	+ hb_iter (all_gids_to_retain)
	\| hb_map ([=] (hb_codepoint_t _) {
	return hb_pair_t<hb_codepoint_t, hb_codepoint_t> (_, _);
	})
	\| hb_sink (reverse_glyph_map)
	;

	// TODO(grieger): Should we discard glyphs past the max glyph to keep?
	// *num_glyphs = + hb_iter (all_gids_to_retain) \| hb_reduce (hb_max, 0);
	*num_glyphs = face->get_num_glyphs ();
	}

	+ reverse_glyph_map->iter ()
	\| hb_map (&hb_pair_t<hb_codepoint_t, hb_codepoint_t>::reverse)
	\| hb_sink (glyph_map)
	;
	}

	/**
	* hb_subset_plan_create:
	* Computes a plan for subsetting the supplied face according
	* to a provided input. The plan describes
	* which tables and glyphs should be retained.
	*
	* Return value: New subset plan.
	*
	* Since: 1.7.5
	**/
	hb_subset_plan_t *
	hb_subset_plan_create (hb_face_t *face,
	hb_subset_input_t *input)
	{
	hb_subset_plan_t *plan = hb_object_create<hb_subset_plan_t> ();

	plan->drop_hints = input->drop_hints;
	plan->drop_layout = input->drop_layout;
	plan->desubroutinize = input->desubroutinize;
	plan->retain_gids = input->retain_gids;
	plan->unicodes = hb_set_create ();
	plan->name_ids = hb_set_reference (input->name_ids);
	/* TODO Clean this up... */
	if (hb_set_is_empty (plan->name_ids))
	hb_set_add_range (plan->name_ids, 0, 0x7FFF);
	plan->source = hb_face_reference (face);
	plan->dest = hb_face_builder_create ();
	plan->codepoint_to_glyph = hb_map_create ();
	plan->glyph_map = hb_map_create ();
	plan->reverse_glyph_map = hb_map_create ();
	plan->_glyphset = _populate_gids_to_retain (face,
	input->unicodes,
	input->glyphs,
	!plan->drop_layout,
	plan->unicodes,
	plan->codepoint_to_glyph);

	_create_old_gid_to_new_gid_map (face,
	input->retain_gids,
	plan->_glyphset,
	plan->glyph_map,
	plan->reverse_glyph_map,
	&plan->_num_output_glyphs);

	return plan;
	}

	/**
	* hb_subset_plan_destroy:
	*
	* Since: 1.7.5
	**/
	void
	hb_subset_plan_destroy (hb_subset_plan_t *plan)
	{
	if (!hb_object_destroy (plan)) return;

	hb_set_destroy (plan->unicodes);
	hb_set_destroy (plan->name_ids);
	hb_face_destroy (plan->source);
	hb_face_destroy (plan->dest);
	hb_map_destroy (plan->codepoint_to_glyph);
	hb_map_destroy (plan->glyph_map);
	hb_map_destroy (plan->reverse_glyph_map);
	hb_set_destroy (plan->_glyphset);

	free (plan);
	}