1/*
2 * Copyright © 2018 Adobe 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 * Adobe Author(s): Michiharu Ariza
25 */
26
27#include "hb.hh"
28
29#ifndef HB_NO_SUBSET_CFF
30
31#include "hb-ot-cff-common.hh"
32#include "hb-ot-cff2-table.hh"
33#include "hb-subset-cff-common.hh"
34
35/* Disable FDSelect format 0 for compatibility with fonttools which doesn't seem choose it.
36 * Rarely any/much smaller than format 3 anyway. */
37#define CFF_SERIALIZE_FDSELECT_0 0
38
39using namespace CFF;
40
41/**
42 * hb_plan_subset_cff_fdselect
43 * Determine an optimal FDSelect format according to a provided plan.
44 *
45 * Return value: FDSelect format, size, and ranges for the most compact subset FDSelect
46 * along with a font index remapping table
47 **/
48
49bool
50hb_plan_subset_cff_fdselect (const hb_subset_plan_t *plan,
51 unsigned int fdCount,
52 const FDSelect &src, /* IN */
53 unsigned int &subset_fd_count /* OUT */,
54 unsigned int &subset_fdselect_size /* OUT */,
55 unsigned int &subset_fdselect_format /* OUT */,
56 hb_vector_t<code_pair_t> &fdselect_ranges /* OUT */,
57 hb_inc_bimap_t &fdmap /* OUT */)
58{
59 subset_fd_count = 0;
60 subset_fdselect_size = 0;
61 subset_fdselect_format = 0;
62 unsigned int num_ranges = 0;
63
64 unsigned int subset_num_glyphs = plan->num_output_glyphs ();
65 if (subset_num_glyphs == 0)
66 return true;
67
68 {
69 /* use hb_set to determine the subset of font dicts */
70 hb_set_t *set = hb_set_create ();
71 if (unlikely (set == &Null (hb_set_t))) return false;
72 hb_codepoint_t prev_fd = CFF_UNDEF_CODE;
73 for (hb_codepoint_t i = 0; i < subset_num_glyphs; i++)
74 {
75 hb_codepoint_t glyph;
76 hb_codepoint_t fd;
77 if (!plan->old_gid_for_new_gid (i, &glyph))
78 {
79 /* fonttools retains FDSelect & font dicts for missing glyphs. do the same */
80 glyph = i;
81 }
82 fd = src.get_fd (glyph);
83 set->add (fd);
84
85 if (fd != prev_fd)
86 {
87 num_ranges++;
88 prev_fd = fd;
89 code_pair_t pair = { fd, i };
90 fdselect_ranges.push (pair);
91 }
92 }
93
94 subset_fd_count = set->get_population ();
95 if (subset_fd_count == fdCount)
96 {
97 /* all font dicts belong to the subset. no need to subset FDSelect & FDArray */
98 fdmap.identity (fdCount);
99 hb_set_destroy (set);
100 }
101 else
102 {
103 /* create a fdmap */
104 fdmap.reset ();
105
106 hb_codepoint_t fd = CFF_UNDEF_CODE;
107 while (set->next (&fd))
108 fdmap.add (fd);
109 hb_set_destroy (set);
110 if (unlikely (fdmap.get_population () != subset_fd_count))
111 return false;
112 }
113
114 /* update each font dict index stored as "code" in fdselect_ranges */
115 for (unsigned int i = 0; i < fdselect_ranges.length; i++)
116 fdselect_ranges[i].code = fdmap[fdselect_ranges[i].code];
117 }
118
119 /* determine which FDSelect format is most compact */
120 if (subset_fd_count > 0xFF)
121 {
122 if (unlikely (src.format != 4))
123 return false;
124 subset_fdselect_format = 4;
125 subset_fdselect_size = FDSelect::min_size + FDSelect4::min_size + FDSelect4_Range::static_size * num_ranges + HBUINT32::static_size;
126 }
127 else
128 {
129#if CFF_SERIALIZE_FDSELECT_0
130 unsigned int format0_size = FDSelect::min_size + FDSelect0::min_size + HBUINT8::static_size * subset_num_glyphs;
131#endif
132 unsigned int format3_size = FDSelect::min_size + FDSelect3::min_size + FDSelect3_Range::static_size * num_ranges + HBUINT16::static_size;
133
134#if CFF_SERIALIZE_FDSELECT_0
135 if (format0_size <= format3_size)
136 {
137 // subset_fdselect_format = 0;
138 subset_fdselect_size = format0_size;
139 }
140 else
141#endif
142 {
143 subset_fdselect_format = 3;
144 subset_fdselect_size = format3_size;
145 }
146 }
147
148 return true;
149}
150
151template <typename FDSELECT3_4>
152static inline bool
153serialize_fdselect_3_4 (hb_serialize_context_t *c,
154 const unsigned int num_glyphs,
155 const FDSelect &src,
156 unsigned int size,
157 const hb_vector_t<code_pair_t> &fdselect_ranges)
158{
159 TRACE_SERIALIZE (this);
160 FDSELECT3_4 *p = c->allocate_size<FDSELECT3_4> (size);
161 if (unlikely (!p)) return_trace (false);
162 p->nRanges () = fdselect_ranges.length;
163 for (unsigned int i = 0; i < fdselect_ranges.length; i++)
164 {
165 p->ranges[i].first = fdselect_ranges[i].glyph;
166 p->ranges[i].fd = fdselect_ranges[i].code;
167 }
168 p->sentinel () = num_glyphs;
169 return_trace (true);
170}
171
172/**
173 * hb_serialize_cff_fdselect
174 * Serialize a subset FDSelect format planned above.
175 **/
176bool
177hb_serialize_cff_fdselect (hb_serialize_context_t *c,
178 const unsigned int num_glyphs,
179 const FDSelect &src,
180 unsigned int fd_count,
181 unsigned int fdselect_format,
182 unsigned int size,
183 const hb_vector_t<code_pair_t> &fdselect_ranges)
184{
185 TRACE_SERIALIZE (this);
186 FDSelect *p = c->allocate_min<FDSelect> ();
187 if (unlikely (!p)) return_trace (false);
188 p->format = fdselect_format;
189 size -= FDSelect::min_size;
190
191 switch (fdselect_format)
192 {
193#if CFF_SERIALIZE_FDSELECT_0
194 case 0:
195 {
196 FDSelect0 *p = c->allocate_size<FDSelect0> (size);
197 if (unlikely (!p)) return_trace (false);
198 unsigned int range_index = 0;
199 unsigned int fd = fdselect_ranges[range_index++].code;
200 for (unsigned int i = 0; i < num_glyphs; i++)
201 {
202 if ((range_index < fdselect_ranges.len) &&
203 (i >= fdselect_ranges[range_index].glyph))
204 {
205 fd = fdselect_ranges[range_index++].code;
206 }
207 p->fds[i] = fd;
208 }
209 return_trace (true);
210 }
211#endif /* CFF_SERIALIZE_FDSELECT_0 */
212
213 case 3:
214 return serialize_fdselect_3_4<FDSelect3> (c, num_glyphs, src,
215 size, fdselect_ranges);
216
217 case 4:
218 return serialize_fdselect_3_4<FDSelect4> (c, num_glyphs, src,
219 size, fdselect_ranges);
220
221 default:
222 return_trace (false);
223 }
224}
225
226
227#endif
228