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-open-type.hh"
28 #include "hb-ot-cff2-table.hh"
29 #include "hb-set.h"
30 #include "hb-subset-cff2.hh"
31 #include "hb-subset-plan.hh"
32 #include "hb-subset-cff-common.hh"
33 #include "hb-cff2-interp-cs.hh"
34
35 using namespace CFF;
36
37 struct cff2_sub_table_offsets_t : cff_sub_table_offsets_t
38 {
39 cff2_sub_table_offsets_t ()
40 : cff_sub_table_offsets_t (),
41 varStoreOffset (0)
42 {}
43
44 unsigned int varStoreOffset;
45 };
46
47 struct cff2_top_dict_op_serializer_t : cff_top_dict_op_serializer_t<>
48 {
49 bool serialize (hb_serialize_context_t *c,
50 const op_str_t &opstr,
51 const cff2_sub_table_offsets_t &offsets) const
52 {
53 TRACE_SERIALIZE (this);
54
55 switch (opstr.op)
56 {
57 case OpCode_vstore:
58 return_trace (FontDict::serialize_offset4_op(c, opstr.op, offsets.varStoreOffset));
59
60 default:
61 return_trace (cff_top_dict_op_serializer_t<>::serialize (c, opstr, offsets));
62 }
63 }
64
65 unsigned int calculate_serialized_size (const op_str_t &opstr) const
66 {
67 switch (opstr.op)
68 {
69 case OpCode_vstore:
70 return OpCode_Size (OpCode_longintdict) + 4 + OpCode_Size (opstr.op);
71
72 default:
73 return cff_top_dict_op_serializer_t<>::calculate_serialized_size (opstr);
74 }
75 }
76 };
77
78 struct cff2_cs_opset_flatten_t : cff2_cs_opset_t<cff2_cs_opset_flatten_t, flatten_param_t>
79 {
80 static void flush_args_and_op (op_code_t op, cff2_cs_interp_env_t &env, flatten_param_t& param)
81 {
82 switch (op)
83 {
84 case OpCode_return:
85 case OpCode_endchar:
86 /* dummy opcodes in CFF2. ignore */
87 break;
88
89 case OpCode_hstem:
90 case OpCode_hstemhm:
91 case OpCode_vstem:
92 case OpCode_vstemhm:
93 case OpCode_hintmask:
94 case OpCode_cntrmask:
95 if (param.drop_hints)
96 {
97 env.clear_args ();
98 return;
99 }
100 HB_FALLTHROUGH;
101
102 default:
103 SUPER::flush_args_and_op (op, env, param);
104 break;
105 }
106 }
107
108 static void flush_args (cff2_cs_interp_env_t &env, flatten_param_t& param)
109 {
110 for (unsigned int i = 0; i < env.argStack.get_count ();)
111 {
112 const blend_arg_t &arg = env.argStack[i];
113 if (arg.blending ())
114 {
115 if (unlikely (!((arg.numValues > 0) && (env.argStack.get_count () >= arg.numValues))))
116 {
117 env.set_error ();
118 return;
119 }
120 flatten_blends (arg, i, env, param);
121 i += arg.numValues;
122 }
123 else
124 {
125 str_encoder_t encoder (param.flatStr);
126 encoder.encode_num (arg);
127 i++;
128 }
129 }
130 SUPER::flush_args (env, param);
131 }
132
133 static void flatten_blends (const blend_arg_t &arg, unsigned int i, cff2_cs_interp_env_t &env, flatten_param_t& param)
134 {
135 /* flatten the default values */
136 str_encoder_t encoder (param.flatStr);
137 for (unsigned int j = 0; j < arg.numValues; j++)
138 {
139 const blend_arg_t &arg1 = env.argStack[i + j];
140 if (unlikely (!((arg1.blending () && (arg.numValues == arg1.numValues) && (arg1.valueIndex == j) &&
141 (arg1.deltas.length == env.get_region_count ())))))
142 {
143 env.set_error ();
144 return;
145 }
146 encoder.encode_num (arg1);
147 }
148 /* flatten deltas for each value */
149 for (unsigned int j = 0; j < arg.numValues; j++)
150 {
151 const blend_arg_t &arg1 = env.argStack[i + j];
152 for (unsigned int k = 0; k < arg1.deltas.length; k++)
153 encoder.encode_num (arg1.deltas[k]);
154 }
155 /* flatten the number of values followed by blend operator */
156 encoder.encode_int (arg.numValues);
157 encoder.encode_op (OpCode_blendcs);
158 }
159
160 static void flush_op (op_code_t op, cff2_cs_interp_env_t &env, flatten_param_t& param)
161 {
162 switch (op)
163 {
164 case OpCode_return:
165 case OpCode_endchar:
166 return;
167 default:
168 str_encoder_t encoder (param.flatStr);
169 encoder.encode_op (op);
170 }
171 }
172
173 private:
174 typedef cff2_cs_opset_t<cff2_cs_opset_flatten_t, flatten_param_t> SUPER;
175 typedef cs_opset_t<blend_arg_t, cff2_cs_opset_flatten_t, cff2_cs_opset_flatten_t, cff2_cs_interp_env_t, flatten_param_t> CSOPSET;
176 };
177
178 struct cff2_cs_opset_subr_subset_t : cff2_cs_opset_t<cff2_cs_opset_subr_subset_t, subr_subset_param_t>
179 {
180 static void process_op (op_code_t op, cff2_cs_interp_env_t &env, subr_subset_param_t& param)
181 {
182 switch (op) {
183
184 case OpCode_return:
185 param.current_parsed_str->set_parsed ();
186 env.returnFromSubr ();
187 param.set_current_str (env, false);
188 break;
189
190 case OpCode_endchar:
191 param.current_parsed_str->set_parsed ();
192 SUPER::process_op (op, env, param);
193 break;
194
195 case OpCode_callsubr:
196 process_call_subr (op, CSType_LocalSubr, env, param, env.localSubrs, param.local_closure);
197 break;
198
199 case OpCode_callgsubr:
200 process_call_subr (op, CSType_GlobalSubr, env, param, env.globalSubrs, param.global_closure);
201 break;
202
203 default:
204 SUPER::process_op (op, env, param);
205 param.current_parsed_str->add_op (op, env.str_ref);
206 break;
207 }
208 }
209
210 protected:
211 static void process_call_subr (op_code_t op, cs_type_t type,
212 cff2_cs_interp_env_t &env, subr_subset_param_t& param,
213 cff2_biased_subrs_t& subrs, hb_set_t *closure)
214 {
215 byte_str_ref_t str_ref = env.str_ref;
216 env.callSubr (subrs, type);
217 param.current_parsed_str->add_call_op (op, str_ref, env.context.subr_num);
218 hb_set_add (closure, env.context.subr_num);
219 param.set_current_str (env, true);
220 }
221
222 private:
223 typedef cff2_cs_opset_t<cff2_cs_opset_subr_subset_t, subr_subset_param_t> SUPER;
224 };
225
226 struct cff2_subr_subsetter_t : subr_subsetter_t<cff2_subr_subsetter_t, CFF2Subrs, const OT::cff2::accelerator_subset_t, cff2_cs_interp_env_t, cff2_cs_opset_subr_subset_t>
227 {
228 static void finalize_parsed_str (cff2_cs_interp_env_t &env, subr_subset_param_t& param, parsed_cs_str_t &charstring)
229 {
230 /* vsindex is inserted at the beginning of the charstring as necessary */
231 if (env.seen_vsindex ())
232 {
233 number_t ivs;
234 ivs.set_int ((int)env.get_ivs ());
235 charstring.set_prefix (ivs, OpCode_vsindexcs);
236 }
237 }
238 };
239
240 struct cff2_subset_plan {
241 cff2_subset_plan ()
242 : final_size (0),
243 orig_fdcount (0),
244 subset_fdcount(1),
245 subset_fdselect_format (0),
246 drop_hints (false),
247 desubroutinize (false)
248 {
249 subset_fdselect_ranges.init ();
250 fdmap.init ();
251 subset_charstrings.init ();
252 subset_globalsubrs.init ();
253 subset_localsubrs.init ();
254 privateDictInfos.init ();
255 }
256
257 ~cff2_subset_plan ()
258 {
259 subset_fdselect_ranges.fini ();
260 fdmap.fini ();
261 subset_charstrings.fini_deep ();
262 subset_globalsubrs.fini_deep ();
263 subset_localsubrs.fini_deep ();
264 privateDictInfos.fini ();
265 }
266
267 bool create (const OT::cff2::accelerator_subset_t &acc,
268 hb_subset_plan_t *plan)
269 {
270 final_size = 0;
271 orig_fdcount = acc.fdArray->count;
272
273 drop_hints = plan->drop_hints;
274 desubroutinize = plan->desubroutinize;
275
276 /* CFF2 header */
277 final_size += OT::cff2::static_size;
278
279 /* top dict */
280 {
281 cff2_top_dict_op_serializer_t topSzr;
282 offsets.topDictInfo.size = TopDict::calculate_serialized_size (acc.topDict, topSzr);
283 final_size += offsets.topDictInfo.size;
284 }
285
286 if (desubroutinize)
287 {
288 /* Flatten global & local subrs */
289 subr_flattener_t<const OT::cff2::accelerator_subset_t, cff2_cs_interp_env_t, cff2_cs_opset_flatten_t>
290 flattener(acc, plan->glyphs, plan->drop_hints);
291 if (!flattener.flatten (subset_charstrings))
292 return false;
293
294 /* no global/local subroutines */
295 offsets.globalSubrsInfo.size = CFF2Subrs::calculate_serialized_size (1, 0, 0);
296 }
297 else
298 {
299 /* Subset subrs: collect used subroutines, leaving all unused ones behind */
300 if (!subr_subsetter.subset (acc, plan->glyphs, plan->drop_hints))
301 return false;
302
303 /* encode charstrings, global subrs, local subrs with new subroutine numbers */
304 if (!subr_subsetter.encode_charstrings (acc, plan->glyphs, subset_charstrings))
305 return false;
306
307 if (!subr_subsetter.encode_globalsubrs (subset_globalsubrs))
308 return false;
309
310 /* global subrs */
311 unsigned int dataSize = subset_globalsubrs.total_size ();
312 offsets.globalSubrsInfo.offSize = calcOffSize (dataSize);
313 offsets.globalSubrsInfo.size = CFF2Subrs::calculate_serialized_size (offsets.globalSubrsInfo.offSize, subset_globalsubrs.length, dataSize);
314
315 /* local subrs */
316 if (!offsets.localSubrsInfos.resize (orig_fdcount))
317 return false;
318 if (!subset_localsubrs.resize (orig_fdcount))
319 return false;
320 for (unsigned int fd = 0; fd < orig_fdcount; fd++)
321 {
322 subset_localsubrs[fd].init ();
323 offsets.localSubrsInfos[fd].init ();
324 if (fdmap.includes (fd))
325 {
326 if (!subr_subsetter.encode_localsubrs (fd, subset_localsubrs[fd]))
327 return false;
328
329 unsigned int dataSize = subset_localsubrs[fd].total_size ();
330 if (dataSize > 0)
331 {
332 offsets.localSubrsInfos[fd].offset = final_size;
333 offsets.localSubrsInfos[fd].offSize = calcOffSize (dataSize);
334 offsets.localSubrsInfos[fd].size = CFF2Subrs::calculate_serialized_size (offsets.localSubrsInfos[fd].offSize, subset_localsubrs[fd].length, dataSize);
335 }
336 }
337 }
338 }
339
340 /* global subrs */
341 offsets.globalSubrsInfo.offset = final_size;
342 final_size += offsets.globalSubrsInfo.size;
343
344 /* variation store */
345 if (acc.varStore != &Null(CFF2VariationStore))
346 {
347 offsets.varStoreOffset = final_size;
348 final_size += acc.varStore->get_size ();
349 }
350
351 /* FDSelect */
352 if (acc.fdSelect != &Null(CFF2FDSelect))
353 {
354 offsets.FDSelectInfo.offset = final_size;
355 if (unlikely (!hb_plan_subset_cff_fdselect (plan->glyphs,
356 orig_fdcount,
357 *(const FDSelect *)acc.fdSelect,
358 subset_fdcount,
359 offsets.FDSelectInfo.size,
360 subset_fdselect_format,
361 subset_fdselect_ranges,
362 fdmap)))
363 return false;
364
365 final_size += offsets.FDSelectInfo.size;
366 }
367 else
368 fdmap.identity (1);
369
370 /* FDArray (FDIndex) */
371 {
372 offsets.FDArrayInfo.offset = final_size;
373 cff_font_dict_op_serializer_t fontSzr;
374 unsigned int dictsSize = 0;
375 for (unsigned int i = 0; i < acc.fontDicts.length; i++)
376 if (fdmap.includes (i))
377 dictsSize += FontDict::calculate_serialized_size (acc.fontDicts[i], fontSzr);
378
379 offsets.FDArrayInfo.offSize = calcOffSize (dictsSize);
380 final_size += CFF2Index::calculate_serialized_size (offsets.FDArrayInfo.offSize, subset_fdcount, dictsSize);
381 }
382
383 /* CharStrings */
384 {
385 offsets.charStringsInfo.offset = final_size;
386 unsigned int dataSize = subset_charstrings.total_size ();
387 offsets.charStringsInfo.offSize = calcOffSize (dataSize);
388 final_size += CFF2CharStrings::calculate_serialized_size (offsets.charStringsInfo.offSize, plan->glyphs.length, dataSize);
389 }
390
391 /* private dicts & local subrs */
392 offsets.privateDictsOffset = final_size;
393 for (unsigned int i = 0; i < orig_fdcount; i++)
394 {
395 if (fdmap.includes (i))
396 {
397 bool has_localsubrs = offsets.localSubrsInfos[i].size > 0;
398 cff_private_dict_op_serializer_t privSzr (desubroutinize, drop_hints);
399 unsigned int priv_size = PrivateDict::calculate_serialized_size (acc.privateDicts[i], privSzr, has_localsubrs);
400 table_info_t privInfo = { final_size, priv_size, 0 };
401 privateDictInfos.push (privInfo);
402 final_size += privInfo.size;
403
404 if (!plan->desubroutinize && has_localsubrs)
405 {
406 offsets.localSubrsInfos[i].offset = final_size;
407 final_size += offsets.localSubrsInfos[i].size;
408 }
409 }
410 }
411
412 return true;
413 }
414
415 unsigned int get_final_size () const { return final_size; }
416
417 unsigned int final_size;
418 cff2_sub_table_offsets_t offsets;
419
420 unsigned int orig_fdcount;
421 unsigned int subset_fdcount;
422 unsigned int subset_fdselect_format;
423 hb_vector_t<code_pair_t> subset_fdselect_ranges;
424
425 remap_t fdmap;
426
427 str_buff_vec_t subset_charstrings;
428 str_buff_vec_t subset_globalsubrs;
429 hb_vector_t<str_buff_vec_t> subset_localsubrs;
430 hb_vector_t<table_info_t> privateDictInfos;
431
432 bool drop_hints;
433 bool desubroutinize;
434 cff2_subr_subsetter_t subr_subsetter;
435 };
436
437 static inline bool _write_cff2 (const cff2_subset_plan &plan,
438 const OT::cff2::accelerator_subset_t &acc,
439 const hb_vector_t<hb_codepoint_t>& glyphs,
440 unsigned int dest_sz,
441 void *dest)
442 {
443 hb_serialize_context_t c (dest, dest_sz);
444
445 OT::cff2 *cff2 = c.start_serialize<OT::cff2> ();
446 if (unlikely (!c.extend_min (*cff2)))
447 return false;
448
449 /* header */
450 cff2->version.major.set (0x02);
451 cff2->version.minor.set (0x00);
452 cff2->topDict.set (OT::cff2::static_size);
453
454 /* top dict */
455 {
456 assert (cff2->topDict == (unsigned) (c.head - c.start));
457 cff2->topDictSize.set (plan.offsets.topDictInfo.size);
458 TopDict &dict = cff2 + cff2->topDict;
459 cff2_top_dict_op_serializer_t topSzr;
460 if (unlikely (!dict.serialize (&c, acc.topDict, topSzr, plan.offsets)))
461 {
462 DEBUG_MSG (SUBSET, nullptr, "failed to serialize CFF2 top dict");
463 return false;
464 }
465 }
466
467 /* global subrs */
468 {
469 assert (cff2->topDict + plan.offsets.topDictInfo.size == (unsigned) (c.head - c.start));
470 CFF2Subrs *dest = c.start_embed <CFF2Subrs> ();
471 if (unlikely (dest == nullptr)) return false;
472 if (unlikely (!dest->serialize (&c, plan.offsets.globalSubrsInfo.offSize, plan.subset_globalsubrs)))
473 {
474 DEBUG_MSG (SUBSET, nullptr, "failed to serialize global subroutines");
475 return false;
476 }
477 }
478
479 /* variation store */
480 if (acc.varStore != &Null(CFF2VariationStore))
481 {
482 assert (plan.offsets.varStoreOffset == (unsigned) (c.head - c.start));
483 CFF2VariationStore *dest = c.start_embed<CFF2VariationStore> ();
484 if (unlikely (!dest->serialize (&c, acc.varStore)))
485 {
486 DEBUG_MSG (SUBSET, nullptr, "failed to serialize CFF2 Variation Store");
487 return false;
488 }
489 }
490
491 /* FDSelect */
492 if (acc.fdSelect != &Null(CFF2FDSelect))
493 {
494 assert (plan.offsets.FDSelectInfo.offset == (unsigned) (c.head - c.start));
495
496 if (unlikely (!hb_serialize_cff_fdselect (&c, glyphs.length, *(const FDSelect *)acc.fdSelect, acc.fdArray->count,
497 plan.subset_fdselect_format, plan.offsets.FDSelectInfo.size,
498 plan.subset_fdselect_ranges)))
499 {
500 DEBUG_MSG (SUBSET, nullptr, "failed to serialize CFF2 subset FDSelect");
501 return false;
502 }
503 }
504
505 /* FDArray (FD Index) */
506 {
507 assert (plan.offsets.FDArrayInfo.offset == (unsigned) (c.head - c.start));
508 CFF2FDArray *fda = c.start_embed<CFF2FDArray> ();
509 if (unlikely (fda == nullptr)) return false;
510 cff_font_dict_op_serializer_t fontSzr;
511 if (unlikely (!fda->serialize (&c, plan.offsets.FDArrayInfo.offSize,
512 acc.fontDicts, plan.subset_fdcount, plan.fdmap,
513 fontSzr, plan.privateDictInfos)))
514 {
515 DEBUG_MSG (SUBSET, nullptr, "failed to serialize CFF2 FDArray");
516 return false;
517 }
518 }
519
520 /* CharStrings */
521 {
522 assert (plan.offsets.charStringsInfo.offset == (unsigned) (c.head - c.start));
523 CFF2CharStrings *cs = c.start_embed<CFF2CharStrings> ();
524 if (unlikely (cs == nullptr)) return false;
525 if (unlikely (!cs->serialize (&c, plan.offsets.charStringsInfo.offSize, plan.subset_charstrings)))
526 {
527 DEBUG_MSG (SUBSET, nullptr, "failed to serialize CFF2 CharStrings");
528 return false;
529 }
530 }
531
532 /* private dicts & local subrs */
533 assert (plan.offsets.privateDictsOffset == (unsigned) (c.head - c.start));
534 for (unsigned int i = 0; i < acc.privateDicts.length; i++)
535 {
536 if (plan.fdmap.includes (i))
537 {
538 PrivateDict *pd = c.start_embed<PrivateDict> ();
539 if (unlikely (pd == nullptr)) return false;
540 unsigned int priv_size = plan.privateDictInfos[plan.fdmap[i]].size;
541 bool result;
542 cff_private_dict_op_serializer_t privSzr (plan.desubroutinize, plan.drop_hints);
543 /* N.B. local subrs immediately follows its corresponding private dict. i.e., subr offset == private dict size */
544 unsigned int subroffset = (plan.offsets.localSubrsInfos[i].size > 0)? priv_size: 0;
545 result = pd->serialize (&c, acc.privateDicts[i], privSzr, subroffset);
546 if (unlikely (!result))
547 {
548 DEBUG_MSG (SUBSET, nullptr, "failed to serialize CFF Private Dict[%d]", i);
549 return false;
550 }
551 if (plan.offsets.localSubrsInfos[i].size > 0)
552 {
553 CFF2Subrs *dest = c.start_embed <CFF2Subrs> ();
554 if (unlikely (dest == nullptr)) return false;
555 if (unlikely (!dest->serialize (&c, plan.offsets.localSubrsInfos[i].offSize, plan.subset_localsubrs[i])))
556 {
557 DEBUG_MSG (SUBSET, nullptr, "failed to serialize local subroutines");
558 return false;
559 }
560 }
561 }
562 }
563
564 assert (c.head == c.end);
565 c.end_serialize ();
566
567 return true;
568 }
569
570 static bool
571 _hb_subset_cff2 (const OT::cff2::accelerator_subset_t &acc,
572 const char *data,
573 hb_subset_plan_t *plan,
574 hb_blob_t **prime /* OUT */)
575 {
576 cff2_subset_plan cff2_plan;
577
578 if (unlikely (!cff2_plan.create (acc, plan)))
579 {
580 DEBUG_MSG(SUBSET, nullptr, "Failed to generate a cff2 subsetting plan.");
581 return false;
582 }
583
584 unsigned int cff2_prime_size = cff2_plan.get_final_size ();
585 char *cff2_prime_data = (char *) calloc (1, cff2_prime_size);
586
587 if (unlikely (!_write_cff2 (cff2_plan, acc, plan->glyphs,
588 cff2_prime_size, cff2_prime_data))) {
589 DEBUG_MSG(SUBSET, nullptr, "Failed to write a subset cff2.");
590 free (cff2_prime_data);
591 return false;
592 }
593
594 *prime = hb_blob_create (cff2_prime_data,
595 cff2_prime_size,
596 HB_MEMORY_MODE_READONLY,
597 cff2_prime_data,
598 free);
599 return true;
600 }
601
602 /**
603 * hb_subset_cff2:
604 * Subsets the CFF2 table according to a provided plan.
605 *
606 * Return value: subsetted cff2 table.
607 **/
608 bool
609 hb_subset_cff2 (hb_subset_plan_t *plan,
610 hb_blob_t **prime /* OUT */)
611 {
612 hb_blob_t *cff2_blob = hb_sanitize_context_t().reference_table<CFF::cff2> (plan->source);
613 const char *data = hb_blob_get_data(cff2_blob, nullptr);
614
615 OT::cff2::accelerator_subset_t acc;
616 acc.init(plan->source);
617 bool result = likely (acc.is_valid ()) &&
618 _hb_subset_cff2 (acc, data, plan, prime);
619
620 hb_blob_destroy (cff2_blob);
621 acc.fini ();
622
623 return result;
624 }