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comparison mupdf-source/thirdparty/harfbuzz/src/graph/classdef-graph.hh @ 2:b50eed0cc0ef upstream

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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1:1d09e1dec1d9 2:b50eed0cc0ef
1 /*
2 * Copyright © 2022 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
25 */
26
27 #include "graph.hh"
28 #include "../hb-ot-layout-common.hh"
29
30 #ifndef GRAPH_CLASSDEF_GRAPH_HH
31 #define GRAPH_CLASSDEF_GRAPH_HH
32
33 namespace graph {
34
35 struct ClassDefFormat1 : public OT::ClassDefFormat1_3<SmallTypes>
36 {
37 bool sanitize (graph_t::vertex_t& vertex) const
38 {
39 int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
40 constexpr unsigned min_size = OT::ClassDefFormat1_3<SmallTypes>::min_size;
41 if (vertex_len < min_size) return false;
42 return vertex_len >= min_size + classValue.get_size () - classValue.len.get_size ();
43 }
44 };
45
46 struct ClassDefFormat2 : public OT::ClassDefFormat2_4<SmallTypes>
47 {
48 bool sanitize (graph_t::vertex_t& vertex) const
49 {
50 int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
51 constexpr unsigned min_size = OT::ClassDefFormat2_4<SmallTypes>::min_size;
52 if (vertex_len < min_size) return false;
53 return vertex_len >= min_size + rangeRecord.get_size () - rangeRecord.len.get_size ();
54 }
55 };
56
57 struct ClassDef : public OT::ClassDef
58 {
59 template<typename It>
60 static bool add_class_def (gsubgpos_graph_context_t& c,
61 unsigned parent_id,
62 unsigned link_position,
63 It glyph_and_class,
64 unsigned max_size)
65 {
66 unsigned class_def_prime_id = c.graph.new_node (nullptr, nullptr);
67 auto& class_def_prime_vertex = c.graph.vertices_[class_def_prime_id];
68 if (!make_class_def (c, glyph_and_class, class_def_prime_id, max_size))
69 return false;
70
71 auto* class_def_link = c.graph.vertices_[parent_id].obj.real_links.push ();
72 class_def_link->width = SmallTypes::size;
73 class_def_link->objidx = class_def_prime_id;
74 class_def_link->position = link_position;
75 class_def_prime_vertex.parents.push (parent_id);
76
77 return true;
78 }
79
80 template<typename It>
81 static bool make_class_def (gsubgpos_graph_context_t& c,
82 It glyph_and_class,
83 unsigned dest_obj,
84 unsigned max_size)
85 {
86 char* buffer = (char*) hb_calloc (1, max_size);
87 hb_serialize_context_t serializer (buffer, max_size);
88 OT::ClassDef_serialize (&serializer, glyph_and_class);
89 serializer.end_serialize ();
90 if (serializer.in_error ())
91 {
92 hb_free (buffer);
93 return false;
94 }
95
96 hb_bytes_t class_def_copy = serializer.copy_bytes ();
97 c.add_buffer ((char *) class_def_copy.arrayZ); // Give ownership to the context, it will cleanup the buffer.
98
99 auto& obj = c.graph.vertices_[dest_obj].obj;
100 obj.head = (char *) class_def_copy.arrayZ;
101 obj.tail = obj.head + class_def_copy.length;
102
103 hb_free (buffer);
104 return true;
105 }
106
107 bool sanitize (graph_t::vertex_t& vertex) const
108 {
109 int64_t vertex_len = vertex.obj.tail - vertex.obj.head;
110 if (vertex_len < OT::ClassDef::min_size) return false;
111 switch (u.format)
112 {
113 case 1: return ((ClassDefFormat1*)this)->sanitize (vertex);
114 case 2: return ((ClassDefFormat2*)this)->sanitize (vertex);
115 #ifndef HB_NO_BEYOND_64K
116 // Not currently supported
117 case 3:
118 case 4:
119 #endif
120 default: return false;
121 }
122 }
123 };
124
125
126 struct class_def_size_estimator_t
127 {
128 template<typename It>
129 class_def_size_estimator_t (It glyph_and_class)
130 : gids_consecutive (true), num_ranges_per_class (), glyphs_per_class ()
131 {
132 unsigned last_gid = (unsigned) -1;
133 for (auto p : + glyph_and_class)
134 {
135 unsigned gid = p.first;
136 unsigned klass = p.second;
137
138 if (last_gid != (unsigned) -1 && gid != last_gid + 1)
139 gids_consecutive = false;
140 last_gid = gid;
141
142 hb_set_t* glyphs;
143 if (glyphs_per_class.has (klass, &glyphs) && glyphs) {
144 glyphs->add (gid);
145 continue;
146 }
147
148 hb_set_t new_glyphs;
149 new_glyphs.add (gid);
150 glyphs_per_class.set (klass, std::move (new_glyphs));
151 }
152
153 if (in_error ()) return;
154
155 for (unsigned klass : glyphs_per_class.keys ())
156 {
157 if (!klass) continue; // class 0 doesn't get encoded.
158
159 const hb_set_t& glyphs = glyphs_per_class.get (klass);
160 hb_codepoint_t start = HB_SET_VALUE_INVALID;
161 hb_codepoint_t end = HB_SET_VALUE_INVALID;
162
163 unsigned count = 0;
164 while (glyphs.next_range (&start, &end))
165 count++;
166
167 num_ranges_per_class.set (klass, count);
168 }
169 }
170
171 // Incremental increase in the Coverage and ClassDef table size
172 // (worst case) if all glyphs associated with 'klass' were added.
173 unsigned incremental_coverage_size (unsigned klass) const
174 {
175 // Coverage takes 2 bytes per glyph worst case,
176 return 2 * glyphs_per_class.get (klass).get_population ();
177 }
178
179 // Incremental increase in the Coverage and ClassDef table size
180 // (worst case) if all glyphs associated with 'klass' were added.
181 unsigned incremental_class_def_size (unsigned klass) const
182 {
183 // ClassDef takes 6 bytes per range
184 unsigned class_def_2_size = 6 * num_ranges_per_class.get (klass);
185 if (gids_consecutive)
186 {
187 // ClassDef1 takes 2 bytes per glyph, but only can be used
188 // when gids are consecutive.
189 return hb_min (2 * glyphs_per_class.get (klass).get_population (), class_def_2_size);
190 }
191
192 return class_def_2_size;
193 }
194
195 bool in_error ()
196 {
197 if (num_ranges_per_class.in_error ()) return true;
198 if (glyphs_per_class.in_error ()) return true;
199
200 for (const hb_set_t& s : glyphs_per_class.values ())
201 {
202 if (s.in_error ()) return true;
203 }
204 return false;
205 }
206
207 private:
208 bool gids_consecutive;
209 hb_hashmap_t<unsigned, unsigned> num_ranges_per_class;
210 hb_hashmap_t<unsigned, hb_set_t> glyphs_per_class;
211 };
212
213
214 }
215
216 #endif // GRAPH_CLASSDEF_GRAPH_HH