1 /*
2  * Copyright © 2018  Google, Inc.
3  *
4  *  This is part of HarfBuzz, a text shaping library.
5  *
6  * Permission is hereby granted, without written agreement and without
7  * license or royalty fees, to use, copy, modify, and distribute this
8  * software and its documentation for any purpose, provided that the
9  * above copyright notice and the following two paragraphs appear in
10  * all copies of this software.
11  *
12  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16  * DAMAGE.
17  *
18  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
21  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23  *
24  * Google Author(s): Garret Rieger, Roderick Sheeter
25  */
26 
27 #ifndef HB_SUBSET_PLAN_HH
28 #define HB_SUBSET_PLAN_HH
29 
30 #include "hb.hh"
31 
32 #include "hb-subset.h"
33 #include "hb-subset-input.hh"
34 
35 #include "hb-map.hh"
36 #include "hb-set.hh"
37 
38 struct hb_subset_plan_t
39 {
40   hb_object_header_t header;
41 
42   bool successful : 1;
43   bool drop_hints : 1;
44   bool desubroutinize : 1;
45   bool retain_gids : 1;
46   bool name_legacy : 1;
47 
48   // For each cp that we'd like to retain maps to the corresponding gid.
49   hb_set_t *unicodes;
50 
51   // name_ids we would like to retain
52   hb_set_t *name_ids;
53 
54   // name_languages we would like to retain
55   hb_set_t *name_languages;
56 
57   //glyph ids requested to retain
58   hb_set_t *glyphs_requested;
59 
60   // Tables which should be dropped.
61   hb_set_t *drop_tables;
62 
63   // The glyph subset
64   hb_map_t *codepoint_to_glyph;
65 
66   // Old -> New glyph id mapping
67   hb_map_t *glyph_map;
68   hb_map_t *reverse_glyph_map;
69 
70   // Plan is only good for a specific source/dest so keep them with it
71   hb_face_t *source;
72   hb_face_t *dest;
73 
74   unsigned int _num_output_glyphs;
75   hb_set_t *_glyphset;
76   hb_set_t *_glyphset_gsub;
77 
78   //active lookups we'd like to retain
79   hb_map_t *gsub_lookups;
80   hb_map_t *gpos_lookups;
81 
82   //active langsys we'd like to retain
83   hb_hashmap_t<unsigned, hb_set_t *, (unsigned)-1, nullptr> *gsub_langsys;
84   hb_hashmap_t<unsigned, hb_set_t *, (unsigned)-1, nullptr> *gpos_langsys;
85 
86   //active features after removing redundant langsys and prune_features
87   hb_map_t *gsub_features;
88   hb_map_t *gpos_features;
89 
90   //The set of layout item variation store delta set indices to be retained
91   hb_set_t *layout_variation_indices;
92   //Old -> New layout item variation store delta set index mapping
93   hb_map_t *layout_variation_idx_map;
94 
95  public:
96 
in_errorhb_subset_plan_t97   bool in_error () const { return !successful; }
98 
check_successhb_subset_plan_t99   bool check_success(bool success)
100   {
101     successful = (successful && success);
102     return successful;
103   }
104 
105   /*
106    * The set of input glyph ids which will be retained in the subset.
107    * Does NOT include ids kept due to retain_gids. You probably want to use
108    * glyph_map/reverse_glyph_map.
109    */
110   inline const hb_set_t *
glyphsethb_subset_plan_t111   glyphset () const
112   {
113     return _glyphset;
114   }
115 
116   /*
117    * The set of input glyph ids which will be retained in the subset.
118    */
119   inline const hb_set_t *
glyphset_gsubhb_subset_plan_t120   glyphset_gsub () const
121   {
122     return _glyphset_gsub;
123   }
124 
125   /*
126    * The total number of output glyphs in the final subset.
127    */
128   inline unsigned int
num_output_glyphshb_subset_plan_t129   num_output_glyphs () const
130   {
131     return _num_output_glyphs;
132   }
133 
134   /*
135    * Given an output gid , returns true if that glyph id is an empty
136    * glyph (ie. it's a gid that we are dropping all data for).
137    */
is_empty_glyphhb_subset_plan_t138   inline bool is_empty_glyph (hb_codepoint_t gid) const
139   {
140     return !_glyphset->has (gid);
141   }
142 
new_gid_for_codepointhb_subset_plan_t143   inline bool new_gid_for_codepoint (hb_codepoint_t codepoint,
144 				     hb_codepoint_t *new_gid) const
145   {
146     hb_codepoint_t old_gid = codepoint_to_glyph->get (codepoint);
147     if (old_gid == HB_MAP_VALUE_INVALID)
148       return false;
149 
150     return new_gid_for_old_gid (old_gid, new_gid);
151   }
152 
new_gid_for_old_gidhb_subset_plan_t153   inline bool new_gid_for_old_gid (hb_codepoint_t old_gid,
154 				   hb_codepoint_t *new_gid) const
155   {
156     hb_codepoint_t gid = glyph_map->get (old_gid);
157     if (gid == HB_MAP_VALUE_INVALID)
158       return false;
159 
160     *new_gid = gid;
161     return true;
162   }
163 
old_gid_for_new_gidhb_subset_plan_t164   inline bool old_gid_for_new_gid (hb_codepoint_t  new_gid,
165 				   hb_codepoint_t *old_gid) const
166   {
167     hb_codepoint_t gid = reverse_glyph_map->get (new_gid);
168     if (gid == HB_MAP_VALUE_INVALID)
169       return false;
170 
171     *old_gid = gid;
172     return true;
173   }
174 
175   inline bool
add_tablehb_subset_plan_t176   add_table (hb_tag_t tag,
177 	     hb_blob_t *contents)
178   {
179     if (HB_DEBUG_SUBSET)
180     {
181       hb_blob_t *source_blob = source->reference_table (tag);
182       DEBUG_MSG(SUBSET, nullptr, "add table %c%c%c%c, dest %d bytes, source %d bytes",
183 		HB_UNTAG(tag),
184 		hb_blob_get_length (contents),
185 		hb_blob_get_length (source_blob));
186       hb_blob_destroy (source_blob);
187     }
188     return hb_face_builder_add_table (dest, tag, contents);
189   }
190 };
191 
192 typedef struct hb_subset_plan_t hb_subset_plan_t;
193 
194 HB_INTERNAL hb_subset_plan_t *
195 hb_subset_plan_create (hb_face_t           *face,
196 		       hb_subset_input_t   *input);
197 
198 HB_INTERNAL void
199 hb_subset_plan_destroy (hb_subset_plan_t *plan);
200 
201 #endif /* HB_SUBSET_PLAN_HH */
202