1 /****************************************************************************
2 *
3 * ttpload.c
4 *
5 * TrueType-specific tables loader (body).
6 *
7 * Copyright (C) 1996-2020 by
8 * David Turner, Robert Wilhelm, and Werner Lemberg.
9 *
10 * This file is part of the FreeType project, and may only be used,
11 * modified, and distributed under the terms of the FreeType project
12 * license, LICENSE.TXT. By continuing to use, modify, or distribute
13 * this file you indicate that you have read the license and
14 * understand and accept it fully.
15 *
16 */
17
18
19 #include <ft2build.h>
20 #include FT_INTERNAL_DEBUG_H
21 #include FT_INTERNAL_OBJECTS_H
22 #include FT_INTERNAL_STREAM_H
23 #include FT_TRUETYPE_TAGS_H
24
25 #include "ttpload.h"
26
27 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
28 #include "ttgxvar.h"
29 #endif
30
31 #include "tterrors.h"
32
33
34 /**************************************************************************
35 *
36 * The macro FT_COMPONENT is used in trace mode. It is an implicit
37 * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
38 * messages during execution.
39 */
40 #undef FT_COMPONENT
41 #define FT_COMPONENT ttpload
42
43
44 /**************************************************************************
45 *
46 * @Function:
47 * tt_face_load_loca
48 *
49 * @Description:
50 * Load the locations table.
51 *
52 * @InOut:
53 * face ::
54 * A handle to the target face object.
55 *
56 * @Input:
57 * stream ::
58 * The input stream.
59 *
60 * @Return:
61 * FreeType error code. 0 means success.
62 */
63 FT_LOCAL_DEF( FT_Error )
64 tt_face_load_loca( TT_Face face,
65 FT_Stream stream )
66 {
67 FT_Error error;
68 FT_ULong table_len;
69 FT_Int shift;
70
71
72 /* we need the size of the `glyf' table for malformed `loca' tables */
73 error = face->goto_table( face, TTAG_glyf, stream, &face->glyf_len );
74
75 /* it is possible that a font doesn't have a glyf table at all */
76 /* or its size is zero */
77 if ( FT_ERR_EQ( error, Table_Missing ) )
78 {
79 face->glyf_len = 0;
80 face->glyf_offset = 0;
81 }
82 else if ( error )
83 goto Exit;
84 else
85 {
86 #ifdef FT_CONFIG_OPTION_INCREMENTAL
87 if ( face->root.internal->incremental_interface )
88 face->glyf_offset = 0;
89 else
90 #endif
91 face->glyf_offset = FT_STREAM_POS();
92 }
93
94 FT_TRACE2(( "Locations " ));
95 error = face->goto_table( face, TTAG_loca, stream, &table_len );
96 if ( error )
97 {
98 error = FT_THROW( Locations_Missing );
99 goto Exit;
100 }
101
102 if ( face->header.Index_To_Loc_Format != 0 )
103 {
104 shift = 2;
105
106 if ( table_len >= 0x40000L )
107 {
108 FT_TRACE2(( "table too large\n" ));
109 table_len = 0x3FFFFL;
110 }
111 face->num_locations = table_len >> shift;
112 }
113 else
114 {
115 shift = 1;
116
117 if ( table_len >= 0x20000L )
118 {
119 FT_TRACE2(( "table too large\n" ));
120 table_len = 0x1FFFFL;
121 }
122 face->num_locations = table_len >> shift;
123 }
124
125 if ( face->num_locations != (FT_ULong)face->root.num_glyphs + 1 )
126 {
127 FT_TRACE2(( "glyph count mismatch! loca: %d, maxp: %d\n",
128 face->num_locations - 1, face->root.num_glyphs ));
129
130 /* we only handle the case where `maxp' gives a larger value */
131 if ( face->num_locations <= (FT_ULong)face->root.num_glyphs )
132 {
133 FT_ULong new_loca_len =
134 ( (FT_ULong)face->root.num_glyphs + 1 ) << shift;
135
136 TT_Table entry = face->dir_tables;
137 TT_Table limit = entry + face->num_tables;
138
139 FT_Long pos = (FT_Long)FT_STREAM_POS();
140 FT_Long dist = 0x7FFFFFFFL;
141 FT_Bool found = 0;
142
143
144 /* compute the distance to next table in font file */
145 for ( ; entry < limit; entry++ )
146 {
147 FT_Long diff = (FT_Long)entry->Offset - pos;
148
149
150 if ( diff > 0 && diff < dist )
151 {
152 dist = diff;
153 found = 1;
154 }
155 }
156
157 if ( !found )
158 {
159 /* `loca' is the last table */
160 dist = (FT_Long)stream->size - pos;
161 }
162
163 if ( new_loca_len <= (FT_ULong)dist )
164 {
165 face->num_locations = (FT_ULong)face->root.num_glyphs + 1;
166 table_len = new_loca_len;
167
168 FT_TRACE2(( "adjusting num_locations to %d\n",
169 face->num_locations ));
170 }
171 else
172 {
173 face->root.num_glyphs = face->num_locations
174 ? (FT_Long)face->num_locations - 1 : 0;
175
176 FT_TRACE2(( "adjusting num_glyphs to %d\n",
177 face->root.num_glyphs ));
178 }
179 }
180 }
181
182 /*
183 * Extract the frame. We don't need to decompress it since
184 * we are able to parse it directly.
185 */
186 if ( FT_FRAME_EXTRACT( table_len, face->glyph_locations ) )
187 goto Exit;
188
189 FT_TRACE2(( "loaded\n" ));
190
191 Exit:
192 return error;
193 }
194
195
196 FT_LOCAL_DEF( FT_ULong )
197 tt_face_get_location( TT_Face face,
198 FT_UInt gindex,
199 FT_UInt *asize )
200 {
201 FT_ULong pos1, pos2;
202 FT_Byte* p;
203 FT_Byte* p_limit;
204
205
206 pos1 = pos2 = 0;
207
208 if ( gindex < face->num_locations )
209 {
210 if ( face->header.Index_To_Loc_Format != 0 )
211 {
212 p = face->glyph_locations + gindex * 4;
213 p_limit = face->glyph_locations + face->num_locations * 4;
214
215 pos1 = FT_NEXT_ULONG( p );
216 pos2 = pos1;
217
218 if ( p + 4 <= p_limit )
219 pos2 = FT_NEXT_ULONG( p );
220 }
221 else
222 {
223 p = face->glyph_locations + gindex * 2;
224 p_limit = face->glyph_locations + face->num_locations * 2;
225
226 pos1 = FT_NEXT_USHORT( p );
227 pos2 = pos1;
228
229 if ( p + 2 <= p_limit )
230 pos2 = FT_NEXT_USHORT( p );
231
232 pos1 <<= 1;
233 pos2 <<= 1;
234 }
235 }
236
237 /* Check broken location data. */
238 if ( pos1 > face->glyf_len )
239 {
240 FT_TRACE1(( "tt_face_get_location:"
241 " too large offset (0x%08lx) found for glyph index %ld,\n"
242 " "
243 " exceeding the end of `glyf' table (0x%08lx)\n",
244 pos1, gindex, face->glyf_len ));
245 *asize = 0;
246 return 0;
247 }
248
249 if ( pos2 > face->glyf_len )
250 {
251 /* We try to sanitize the last `loca' entry. */
252 if ( gindex == face->num_locations - 2 )
253 {
254 FT_TRACE1(( "tt_face_get_location:"
255 " too large size (%ld bytes) found for glyph index %ld,\n"
256 " "
257 " truncating at the end of `glyf' table to %ld bytes\n",
258 pos2 - pos1, gindex, face->glyf_len - pos1 ));
259 pos2 = face->glyf_len;
260 }
261 else
262 {
263 FT_TRACE1(( "tt_face_get_location:"
264 " too large offset (0x%08lx) found for glyph index %ld,\n"
265 " "
266 " exceeding the end of `glyf' table (0x%08lx)\n",
267 pos2, gindex + 1, face->glyf_len ));
268 *asize = 0;
269 return 0;
270 }
271 }
272
273 /* The `loca' table must be ordered; it refers to the length of */
274 /* an entry as the difference between the current and the next */
275 /* position. However, there do exist (malformed) fonts which */
276 /* don't obey this rule, so we are only able to provide an */
277 /* upper bound for the size. */
278 /* */
279 /* We get (intentionally) a wrong, non-zero result in case the */
280 /* `glyf' table is missing. */
281 if ( pos2 >= pos1 )
282 *asize = (FT_UInt)( pos2 - pos1 );
283 else
284 *asize = (FT_UInt)( face->glyf_len - pos1 );
285
286 return pos1;
287 }
288
289
290 FT_LOCAL_DEF( void )
291 tt_face_done_loca( TT_Face face )
292 {
293 FT_Stream stream = face->root.stream;
294
295
296 FT_FRAME_RELEASE( face->glyph_locations );
297 face->num_locations = 0;
298 }
299
300
301
302 /**************************************************************************
303 *
304 * @Function:
305 * tt_face_load_cvt
306 *
307 * @Description:
308 * Load the control value table into a face object.
309 *
310 * @InOut:
311 * face ::
312 * A handle to the target face object.
313 *
314 * @Input:
315 * stream ::
316 * A handle to the input stream.
317 *
318 * @Return:
319 * FreeType error code. 0 means success.
320 */
321 FT_LOCAL_DEF( FT_Error )
322 tt_face_load_cvt( TT_Face face,
323 FT_Stream stream )
324 {
325 #ifdef TT_USE_BYTECODE_INTERPRETER
326
327 FT_Error error;
328 FT_Memory memory = stream->memory;
329 FT_ULong table_len;
330
331
332 FT_TRACE2(( "CVT " ));
333
334 error = face->goto_table( face, TTAG_cvt, stream, &table_len );
335 if ( error )
336 {
337 FT_TRACE2(( "is missing\n" ));
338
339 face->cvt_size = 0;
340 face->cvt = NULL;
341 error = FT_Err_Ok;
342
343 goto Exit;
344 }
345
346 face->cvt_size = table_len / 2;
347
348 if ( FT_NEW_ARRAY( face->cvt, face->cvt_size ) )
349 goto Exit;
350
351 if ( FT_FRAME_ENTER( face->cvt_size * 2L ) )
352 goto Exit;
353
354 {
355 FT_Int32* cur = face->cvt;
356 FT_Int32* limit = cur + face->cvt_size;
357
358
359 for ( ; cur < limit; cur++ )
360 *cur = FT_GET_SHORT() * 64;
361 }
362
363 FT_FRAME_EXIT();
364 FT_TRACE2(( "loaded\n" ));
365
366 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
367 if ( face->doblend )
368 error = tt_face_vary_cvt( face, stream );
369 #endif
370
371 Exit:
372 return error;
373
374 #else /* !TT_USE_BYTECODE_INTERPRETER */
375
376 FT_UNUSED( face );
377 FT_UNUSED( stream );
378
379 return FT_Err_Ok;
380
381 #endif
382 }
383
384
385 /**************************************************************************
386 *
387 * @Function:
388 * tt_face_load_fpgm
389 *
390 * @Description:
391 * Load the font program.
392 *
393 * @InOut:
394 * face ::
395 * A handle to the target face object.
396 *
397 * @Input:
398 * stream ::
399 * A handle to the input stream.
400 *
401 * @Return:
402 * FreeType error code. 0 means success.
403 */
404 FT_LOCAL_DEF( FT_Error )
405 tt_face_load_fpgm( TT_Face face,
406 FT_Stream stream )
407 {
408 #ifdef TT_USE_BYTECODE_INTERPRETER
409
410 FT_Error error;
411 FT_ULong table_len;
412
413
414 FT_TRACE2(( "Font program " ));
415
416 /* The font program is optional */
417 error = face->goto_table( face, TTAG_fpgm, stream, &table_len );
418 if ( error )
419 {
420 face->font_program = NULL;
421 face->font_program_size = 0;
422 error = FT_Err_Ok;
423
424 FT_TRACE2(( "is missing\n" ));
425 }
426 else
427 {
428 face->font_program_size = table_len;
429 if ( FT_FRAME_EXTRACT( table_len, face->font_program ) )
430 goto Exit;
431
432 FT_TRACE2(( "loaded, %12d bytes\n", face->font_program_size ));
433 }
434
435 Exit:
436 return error;
437
438 #else /* !TT_USE_BYTECODE_INTERPRETER */
439
440 FT_UNUSED( face );
441 FT_UNUSED( stream );
442
443 return FT_Err_Ok;
444
445 #endif
446 }
447
448
449 /**************************************************************************
450 *
451 * @Function:
452 * tt_face_load_prep
453 *
454 * @Description:
455 * Load the cvt program.
456 *
457 * @InOut:
458 * face ::
459 * A handle to the target face object.
460 *
461 * @Input:
462 * stream ::
463 * A handle to the input stream.
464 *
465 * @Return:
466 * FreeType error code. 0 means success.
467 */
468 FT_LOCAL_DEF( FT_Error )
469 tt_face_load_prep( TT_Face face,
470 FT_Stream stream )
471 {
472 #ifdef TT_USE_BYTECODE_INTERPRETER
473
474 FT_Error error;
475 FT_ULong table_len;
476
477
478 FT_TRACE2(( "Prep program " ));
479
480 error = face->goto_table( face, TTAG_prep, stream, &table_len );
481 if ( error )
482 {
483 face->cvt_program = NULL;
484 face->cvt_program_size = 0;
485 error = FT_Err_Ok;
486
487 FT_TRACE2(( "is missing\n" ));
488 }
489 else
490 {
491 face->cvt_program_size = table_len;
492 if ( FT_FRAME_EXTRACT( table_len, face->cvt_program ) )
493 goto Exit;
494
495 FT_TRACE2(( "loaded, %12d bytes\n", face->cvt_program_size ));
496 }
497
498 Exit:
499 return error;
500
501 #else /* !TT_USE_BYTECODE_INTERPRETER */
502
503 FT_UNUSED( face );
504 FT_UNUSED( stream );
505
506 return FT_Err_Ok;
507
508 #endif
509 }
510
511
512 /**************************************************************************
513 *
514 * @Function:
515 * tt_face_load_hdmx
516 *
517 * @Description:
518 * Load the `hdmx' table into the face object.
519 *
520 * @Input:
521 * face ::
522 * A handle to the target face object.
523 *
524 * stream ::
525 * A handle to the input stream.
526 *
527 * @Return:
528 * FreeType error code. 0 means success.
529 */
530
531 FT_LOCAL_DEF( FT_Error )
532 tt_face_load_hdmx( TT_Face face,
533 FT_Stream stream )
534 {
535 FT_Error error;
536 FT_Memory memory = stream->memory;
537 FT_UInt nn, num_records;
538 FT_ULong table_size, record_size;
539 FT_Byte* p;
540 FT_Byte* limit;
541
542
543 /* this table is optional */
544 error = face->goto_table( face, TTAG_hdmx, stream, &table_size );
545 if ( error || table_size < 8 )
546 return FT_Err_Ok;
547
548 if ( FT_FRAME_EXTRACT( table_size, face->hdmx_table ) )
549 goto Exit;
550
551 p = face->hdmx_table;
552 limit = p + table_size;
553
554 /* Given that `hdmx' tables are losing its importance (for example, */
555 /* variation fonts introduced in OpenType 1.8 must not have this */
556 /* table) we no longer test for a correct `version' field. */
557 p += 2;
558 num_records = FT_NEXT_USHORT( p );
559 record_size = FT_NEXT_ULONG( p );
560
561 /* The maximum number of bytes in an hdmx device record is the */
562 /* maximum number of glyphs + 2; this is 0xFFFF + 2, thus */
563 /* explaining why `record_size' is a long (which we read as */
564 /* unsigned long for convenience). In practice, two bytes are */
565 /* sufficient to hold the size value. */
566 /* */
567 /* There are at least two fonts, HANNOM-A and HANNOM-B version */
568 /* 2.0 (2005), which get this wrong: The upper two bytes of */
569 /* the size value are set to 0xFF instead of 0x00. We catch */
570 /* and fix this. */
571
572 if ( record_size >= 0xFFFF0000UL )
573 record_size &= 0xFFFFU;
574
575 /* The limit for `num_records' is a heuristic value. */
576 if ( num_records > 255 ||
577 ( num_records > 0 &&
578 ( record_size > 0x10001L ||
579 record_size < 4 ) ) )
580 {
581 error = FT_THROW( Invalid_File_Format );
582 goto Fail;
583 }
584
585 if ( FT_NEW_ARRAY( face->hdmx_record_sizes, num_records ) )
586 goto Fail;
587
588 for ( nn = 0; nn < num_records; nn++ )
589 {
590 if ( p + record_size > limit )
591 break;
592
593 face->hdmx_record_sizes[nn] = p[0];
594 p += record_size;
595 }
596
597 face->hdmx_record_count = nn;
598 face->hdmx_table_size = table_size;
599 face->hdmx_record_size = record_size;
600
601 Exit:
602 return error;
603
604 Fail:
605 FT_FRAME_RELEASE( face->hdmx_table );
606 face->hdmx_table_size = 0;
607 goto Exit;
608 }
609
610
611 FT_LOCAL_DEF( void )
612 tt_face_free_hdmx( TT_Face face )
613 {
614 FT_Stream stream = face->root.stream;
615 FT_Memory memory = stream->memory;
616
617
618 FT_FREE( face->hdmx_record_sizes );
619 FT_FRAME_RELEASE( face->hdmx_table );
620 }
621
622
623 /**************************************************************************
624 *
625 * Return the advance width table for a given pixel size if it is found
626 * in the font's `hdmx' table (if any).
627 */
628 FT_LOCAL_DEF( FT_Byte* )
629 tt_face_get_device_metrics( TT_Face face,
630 FT_UInt ppem,
631 FT_UInt gindex )
632 {
633 FT_UInt nn;
634 FT_Byte* result = NULL;
635 FT_ULong record_size = face->hdmx_record_size;
636 FT_Byte* record = FT_OFFSET( face->hdmx_table, 8 );
637
638
639 for ( nn = 0; nn < face->hdmx_record_count; nn++ )
640 if ( face->hdmx_record_sizes[nn] == ppem )
641 {
642 gindex += 2;
643 if ( gindex < record_size )
644 result = record + nn * record_size + gindex;
645 break;
646 }
647
648 return result;
649 }
650
651
652 /* END */