harfbuzz/src/hb-subset-plan.hh

/*
 * 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
 */

#ifndef HB_SUBSET_PLAN_HH
#define HB_SUBSET_PLAN_HH

#include "hb.hh"

#include "hb-subset.h"
#include "hb-subset-input.hh"
#include "hb-subset-accelerator.hh"

#include "hb-map.hh"
#include "hb-bimap.hh"
#include "hb-set.hh"

namespace OT {
struct Feature;
}

struct head_maxp_info_t
{
  head_maxp_info_t ()
      :xMin (0x7FFF), xMax (-0x7FFF), yMin (0x7FFF), yMax (-0x7FFF),
      maxPoints (0), maxContours (0),
      maxCompositePoints (0),
      maxCompositeContours (0),
      maxComponentElements (0),
      maxComponentDepth (0),
      allXMinIsLsb (true) {}

  int xMin;
  int xMax;
  int yMin;
  int yMax;
  unsigned maxPoints;
  unsigned maxContours;
  unsigned maxCompositePoints;
  unsigned maxCompositeContours;
  unsigned maxComponentElements;
  unsigned maxComponentDepth;
  bool allXMinIsLsb;
};

typedef struct head_maxp_info_t head_maxp_info_t;

struct hb_subset_plan_t
{
  HB_INTERNAL hb_subset_plan_t (hb_face_t *,
				const hb_subset_input_t *input);

  ~hb_subset_plan_t()
  {
    hb_face_destroy (source);
    hb_face_destroy (dest);

    hb_map_destroy (codepoint_to_glyph);
    hb_map_destroy (glyph_map);
    hb_map_destroy (reverse_glyph_map);

#ifdef HB_EXPERIMENTAL_API
    for (auto _ : name_table_overrides)
      _.second.fini ();
#endif

    if (inprogress_accelerator)
      hb_subset_accelerator_t::destroy ((void*) inprogress_accelerator);
  }

  hb_object_header_t header;

  bool successful;
  unsigned flags;
  bool attach_accelerator_data = false;
  bool force_long_loca = false;

  // For each cp that we'd like to retain maps to the corresponding gid.
  hb_set_t unicodes;
  hb_sorted_vector_t<hb_pair_t<hb_codepoint_t, hb_codepoint_t>> unicode_to_new_gid_list;

  // name_ids we would like to retain
  hb_set_t name_ids;

  // name_languages we would like to retain
  hb_set_t name_languages;

  //layout features which will be preserved
  hb_set_t layout_features;

  // layout scripts which will be preserved.
  hb_set_t layout_scripts;

  //glyph ids requested to retain
  hb_set_t glyphs_requested;

  // Tables which should not be processed, just pass them through.
  hb_set_t no_subset_tables;

  // Tables which should be dropped.
  hb_set_t drop_tables;

  // The glyph subset
  hb_map_t *codepoint_to_glyph; // Needs to be heap-allocated

  // Old -> New glyph id mapping
  hb_map_t *glyph_map; // Needs to be heap-allocated
  hb_map_t *reverse_glyph_map; // Needs to be heap-allocated
  hb_map_t glyph_map_gsub;

  // Plan is only good for a specific source/dest so keep them with it
  hb_face_t *source;
  hb_face_t *dest;

  unsigned int _num_output_glyphs;
  hb_set_t _glyphset;
  hb_set_t _glyphset_gsub;
  hb_set_t _glyphset_mathed;
  hb_set_t _glyphset_colred;

  //active lookups we'd like to retain
  hb_map_t gsub_lookups;
  hb_map_t gpos_lookups;

  //active langsys we'd like to retain
  hb_hashmap_t<unsigned, hb::unique_ptr<hb_set_t>> gsub_langsys;
  hb_hashmap_t<unsigned, hb::unique_ptr<hb_set_t>> gpos_langsys;

  //active features after removing redundant langsys and prune_features
  hb_map_t gsub_features;
  hb_map_t gpos_features;

  //active feature variation records/condition index with variations
  hb_hashmap_t<unsigned, hb::shared_ptr<hb_set_t>> gsub_feature_record_cond_idx_map;
  hb_hashmap_t<unsigned, hb::shared_ptr<hb_set_t>> gpos_feature_record_cond_idx_map;

  //feature index-> address of substituation feature table mapping with
  //variations
  hb_hashmap_t<unsigned, const OT::Feature*> gsub_feature_substitutes_map;
  hb_hashmap_t<unsigned, const OT::Feature*> gpos_feature_substitutes_map;

  //active layers/palettes we'd like to retain
  hb_map_t colrv1_layers;
  hb_map_t colr_palettes;

  //Old layout item variation index -> (New varidx, delta) mapping
  hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> layout_variation_idx_delta_map;

  //gdef varstore retained varidx mapping
  hb_vector_t<hb_inc_bimap_t> gdef_varstore_inner_maps;

  hb_hashmap_t<hb_tag_t, hb::unique_ptr<hb_blob_t>> sanitized_table_cache;
  //normalized axes location map
  hb_hashmap_t<hb_tag_t, int> axes_location;
  hb_vector_t<int> normalized_coords;
  //user specified axes location map
  hb_hashmap_t<hb_tag_t, float> user_axes_location;
  //retained old axis index -> new axis index mapping in fvar axis array
  hb_map_t axes_index_map;
  //axis_index->axis_tag mapping in fvar axis array
  hb_map_t axes_old_index_tag_map;
  bool all_axes_pinned;
  bool pinned_at_default;
  bool has_seac;

  //hmtx metrics map: new gid->(advance, lsb)
  mutable hb_hashmap_t<hb_codepoint_t, hb_pair_t<unsigned, int>> hmtx_map;
  //vmtx metrics map: new gid->(advance, lsb)
  mutable hb_hashmap_t<hb_codepoint_t, hb_pair_t<unsigned, int>> vmtx_map;
  //boundsWidth map: new gid->boundsWidth, boundWidth=xMax - xMin
  mutable hb_map_t bounds_width_map;
  //boundsHeight map: new gid->boundsHeight, boundsHeight=yMax - yMin
  mutable hb_map_t bounds_height_map;

  //recalculated head/maxp table info after instancing
  mutable head_maxp_info_t head_maxp_info;

#ifdef HB_EXPERIMENTAL_API
  // name table overrides map: hb_ot_name_record_ids_t-> name string new value or
  // None to indicate should remove
  hb_hashmap_t<hb_ot_name_record_ids_t, hb_bytes_t> name_table_overrides;
#endif

  const hb_subset_accelerator_t* accelerator;
  hb_subset_accelerator_t* inprogress_accelerator;

 public:

  template<typename T>
  hb_blob_ptr_t<T> source_table()
  {
    hb_lock_t lock (accelerator ? &accelerator->sanitized_table_cache_lock : nullptr);

    auto *cache = accelerator ? &accelerator->sanitized_table_cache : &sanitized_table_cache;
    if (cache
        && !cache->in_error ()
        && cache->has (+T::tableTag)) {
      return hb_blob_reference (cache->get (+T::tableTag).get ());
    }

    hb::unique_ptr<hb_blob_t> table_blob {hb_sanitize_context_t ().reference_table<T> (source)};
    hb_blob_t* ret = hb_blob_reference (table_blob.get ());

    if (likely (cache))
      cache->set (+T::tableTag, std::move (table_blob));

    return ret;
  }

  bool in_error () const { return !successful; }

  bool check_success(bool success)
  {
    successful = (successful && success);
    return successful;
  }

  /*
   * The set of input glyph ids which will be retained in the subset.
   * Does NOT include ids kept due to retain_gids. You probably want to use
   * glyph_map/reverse_glyph_map.
   */
  inline const hb_set_t *
  glyphset () const
  {
    return &_glyphset;
  }

  /*
   * The set of input glyph ids which will be retained in the subset.
   */
  inline const hb_set_t *
  glyphset_gsub () const
  {
    return &_glyphset_gsub;
  }

  /*
   * The total number of output glyphs in the final subset.
   */
  inline unsigned int
  num_output_glyphs () const
  {
    return _num_output_glyphs;
  }

  /*
   * Given an output gid , returns true if that glyph id is an empty
   * glyph (ie. it's a gid that we are dropping all data for).
   */
  inline bool is_empty_glyph (hb_codepoint_t gid) const
  {
    return !_glyphset.has (gid);
  }

  inline bool new_gid_for_codepoint (hb_codepoint_t codepoint,
				     hb_codepoint_t *new_gid) const
  {
    hb_codepoint_t old_gid = codepoint_to_glyph->get (codepoint);
    if (old_gid == HB_MAP_VALUE_INVALID)
      return false;

    return new_gid_for_old_gid (old_gid, new_gid);
  }

  inline bool new_gid_for_old_gid (hb_codepoint_t old_gid,
				   hb_codepoint_t *new_gid) const
  {
    hb_codepoint_t gid = glyph_map->get (old_gid);
    if (gid == HB_MAP_VALUE_INVALID)
      return false;

    *new_gid = gid;
    return true;
  }

  inline bool old_gid_for_new_gid (hb_codepoint_t  new_gid,
				   hb_codepoint_t *old_gid) const
  {
    hb_codepoint_t gid = reverse_glyph_map->get (new_gid);
    if (gid == HB_MAP_VALUE_INVALID)
      return false;

    *old_gid = gid;
    return true;
  }

  inline bool
  add_table (hb_tag_t tag,
	     hb_blob_t *contents)
  {
    if (HB_DEBUG_SUBSET)
    {
      hb_blob_t *source_blob = source->reference_table (tag);
      DEBUG_MSG(SUBSET, nullptr, "add table %c%c%c%c, dest %u bytes, source %u bytes",
		HB_UNTAG(tag),
		hb_blob_get_length (contents),
		hb_blob_get_length (source_blob));
      hb_blob_destroy (source_blob);
    }
    return hb_face_builder_add_table (dest, tag, contents);
  }
};

#endif /* HB_SUBSET_PLAN_HH */