1 /****************************************************************************
2 *
3 * ttpload.c
4 *
5 * TrueType-specific tables loader (body).
6 *
7 * Copyright (C) 1996-2023 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 <freetype/internal/ftdebug.h>
20 #include <freetype/internal/ftobjs.h>
21 #include <freetype/internal/ftstream.h>
22 #include <freetype/tttags.h>
23
24 #include "ttpload.h"
25
26 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
27 #include "ttgxvar.h"
28 #endif
29
30 #include "tterrors.h"
31
32
33 /**************************************************************************
34 *
35 * The macro FT_COMPONENT is used in trace mode. It is an implicit
36 * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
37 * messages during execution.
38 */
39 #undef FT_COMPONENT
40 #define FT_COMPONENT ttpload
41
42
43 /**************************************************************************
44 *
45 * @Function:
46 * tt_face_load_loca
47 *
48 * @Description:
49 * Load the locations table.
50 *
51 * @InOut:
52 * face ::
53 * A handle to the target face object.
54 *
55 * @Input:
56 * stream ::
57 * The input stream.
58 *
59 * @Return:
60 * FreeType error code. 0 means success.
61 */
62 FT_LOCAL_DEF( FT_Error )
63 tt_face_load_loca( TT_Face face,
64 FT_Stream stream )
65 {
66 FT_Error error;
67 FT_ULong table_len;
68 FT_Int shift;
69
70
71 /* we need the size of the `glyf' table for malformed `loca' tables */
72 error = face->goto_table( face, TTAG_glyf, stream, &face->glyf_len );
73
74 /* it is possible that a font doesn't have a glyf table at all */
75 /* or its size is zero */
76 if ( FT_ERR_EQ( error, Table_Missing ) )
77 {
78 face->glyf_len = 0;
79 face->glyf_offset = 0;
80 }
81 else if ( error )
82 goto Exit;
83 else
84 {
85 #ifdef FT_CONFIG_OPTION_INCREMENTAL
86 if ( face->root.internal->incremental_interface )
87 face->glyf_offset = 0;
88 else
89 #endif
90 face->glyf_offset = FT_STREAM_POS();
91 }
92
93 FT_TRACE2(( "Locations " ));
94 error = face->goto_table( face, TTAG_loca, stream, &table_len );
95 if ( error )
96 {
97 error = FT_THROW( Locations_Missing );
98 goto Exit;
99 }
100
101 shift = face->header.Index_To_Loc_Format != 0 ? 2 : 1;
102
103 if ( table_len > 0x10000UL << shift )
104 {
105 FT_TRACE2(( "table too large\n" ));
106 table_len = 0x10000UL << shift;
107 }
108
109 face->num_locations = table_len >> shift;
110
111 if ( face->num_locations != (FT_ULong)face->root.num_glyphs + 1 )
112 {
113 FT_TRACE2(( "glyph count mismatch! loca: %ld, maxp: %ld\n",
114 face->num_locations - 1, face->root.num_glyphs ));
115
116 /* we only handle the case where `maxp' gives a larger value */
117 if ( face->num_locations < (FT_ULong)face->root.num_glyphs + 1 )
118 {
119 FT_ULong new_loca_len =
120 ( (FT_ULong)face->root.num_glyphs + 1 ) << shift;
121
122 TT_Table entry = face->dir_tables;
123 TT_Table limit = entry + face->num_tables;
124
125 FT_Long pos = (FT_Long)FT_STREAM_POS();
126 FT_Long dist = 0x7FFFFFFFL;
127 FT_Bool found = 0;
128
129
130 /* compute the distance to next table in font file */
131 for ( ; entry < limit; entry++ )
132 {
133 FT_Long diff = (FT_Long)entry->Offset - pos;
134
135
136 if ( diff > 0 && diff < dist )
137 {
138 dist = diff;
139 found = 1;
140 }
141 }
142
143 if ( !found )
144 {
145 /* `loca' is the last table */
146 dist = (FT_Long)stream->size - pos;
147 }
148
149 if ( new_loca_len <= (FT_ULong)dist )
150 {
151 face->num_locations = (FT_ULong)face->root.num_glyphs + 1;
152 table_len = new_loca_len;
153
154 FT_TRACE2(( "adjusting num_locations to %ld\n",
155 face->num_locations ));
156 }
157 else
158 {
159 face->root.num_glyphs = face->num_locations
160 ? (FT_Long)face->num_locations - 1 : 0;
161
162 FT_TRACE2(( "adjusting num_glyphs to %ld\n",
163 face->root.num_glyphs ));
164 }
165 }
166 }
167
168 /*
169 * Extract the frame. We don't need to decompress it since
170 * we are able to parse it directly.
171 */
172 if ( FT_FRAME_EXTRACT( table_len, face->glyph_locations ) )
173 goto Exit;
174
175 FT_TRACE2(( "loaded\n" ));
176
177 Exit:
178 return error;
179 }
180
181
182 FT_LOCAL_DEF( FT_ULong )
183 tt_face_get_location( FT_Face face, /* TT_Face */
184 FT_UInt gindex,
185 FT_ULong *asize )
186 {
187 TT_Face ttface = (TT_Face)face;
188 FT_ULong pos1, pos2;
189 FT_Byte* p;
190 FT_Byte* p_limit;
191
192
193 pos1 = pos2 = 0;
194
195 if ( gindex < ttface->num_locations )
196 {
197 if ( ttface->header.Index_To_Loc_Format != 0 )
198 {
199 p = ttface->glyph_locations + gindex * 4;
200 p_limit = ttface->glyph_locations + ttface->num_locations * 4;
201
202 pos1 = FT_NEXT_ULONG( p );
203 pos2 = pos1;
204
205 if ( p + 4 <= p_limit )
206 pos2 = FT_NEXT_ULONG( p );
207 }
208 else
209 {
210 p = ttface->glyph_locations + gindex * 2;
211 p_limit = ttface->glyph_locations + ttface->num_locations * 2;
212
213 pos1 = FT_NEXT_USHORT( p );
214 pos2 = pos1;
215
216 if ( p + 2 <= p_limit )
217 pos2 = FT_NEXT_USHORT( p );
218
219 pos1 <<= 1;
220 pos2 <<= 1;
221 }
222 }
223
224 /* Check broken location data. */
225 if ( pos1 > ttface->glyf_len )
226 {
227 FT_TRACE1(( "tt_face_get_location:"
228 " too large offset (0x%08lx) found for glyph index %d,\n",
229 pos1, gindex ));
230 FT_TRACE1(( " "
231 " exceeding the end of `glyf' table (0x%08lx)\n",
232 ttface->glyf_len ));
233 *asize = 0;
234 return 0;
235 }
236
237 if ( pos2 > ttface->glyf_len )
238 {
239 /* We try to sanitize the last `loca' entry. */
240 if ( gindex == ttface->num_locations - 2 )
241 {
242 FT_TRACE1(( "tt_face_get_location:"
243 " too large size (%ld bytes) found for glyph index %d,\n",
244 pos2 - pos1, gindex ));
245 FT_TRACE1(( " "
246 " truncating at the end of `glyf' table to %ld bytes\n",
247 ttface->glyf_len - pos1 ));
248 pos2 = ttface->glyf_len;
249 }
250 else
251 {
252 FT_TRACE1(( "tt_face_get_location:"
253 " too large offset (0x%08lx) found for glyph index %d,\n",
254 pos2, gindex + 1 ));
255 FT_TRACE1(( " "
256 " exceeding the end of `glyf' table (0x%08lx)\n",
257 ttface->glyf_len ));
258 *asize = 0;
259 return 0;
260 }
261 }
262
263 /* The `loca' table must be ordered; it refers to the length of */
264 /* an entry as the difference between the current and the next */
265 /* position. However, there do exist (malformed) fonts which */
266 /* don't obey this rule, so we are only able to provide an */
267 /* upper bound for the size. */
268 /* */
269 /* We get (intentionally) a wrong, non-zero result in case the */
270 /* `glyf' table is missing. */
271 if ( pos2 >= pos1 )
272 *asize = (FT_ULong)( pos2 - pos1 );
273 else
274 *asize = (FT_ULong)( ttface->glyf_len - pos1 );
275
276 return pos1;
277 }
278
279
280 FT_LOCAL_DEF( void )
281 tt_face_done_loca( TT_Face face )
282 {
283 FT_Stream stream = face->root.stream;
284
285
286 FT_FRAME_RELEASE( face->glyph_locations );
287 face->num_locations = 0;
288 }
289
290
291
292 /**************************************************************************
293 *
294 * @Function:
295 * tt_face_load_cvt
296 *
297 * @Description:
298 * Load the control value table into a face object.
299 *
300 * @InOut:
301 * face ::
302 * A handle to the target face object.
303 *
304 * @Input:
305 * stream ::
306 * A handle to the input stream.
307 *
308 * @Return:
309 * FreeType error code. 0 means success.
310 */
311 FT_LOCAL_DEF( FT_Error )
312 tt_face_load_cvt( TT_Face face,
313 FT_Stream stream )
314 {
315 #ifdef TT_USE_BYTECODE_INTERPRETER
316
317 FT_Error error;
318 FT_Memory memory = stream->memory;
319 FT_ULong table_len;
320
321
322 FT_TRACE2(( "CVT " ));
323
324 error = face->goto_table( face, TTAG_cvt, stream, &table_len );
325 if ( error )
326 {
327 FT_TRACE2(( "is missing\n" ));
328
329 face->cvt_size = 0;
330 face->cvt = NULL;
331 error = FT_Err_Ok;
332
333 goto Exit;
334 }
335
336 face->cvt_size = table_len / 2;
337
338 if ( FT_QNEW_ARRAY( face->cvt, face->cvt_size ) )
339 goto Exit;
340
341 if ( FT_FRAME_ENTER( face->cvt_size * 2L ) )
342 goto Exit;
343
344 {
345 FT_Int32* cur = face->cvt;
346 FT_Int32* limit = cur + face->cvt_size;
347
348
349 for ( ; cur < limit; cur++ )
350 *cur = FT_GET_SHORT() * 64;
351 }
352
353 FT_FRAME_EXIT();
354 FT_TRACE2(( "loaded\n" ));
355
356 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
357 if ( face->doblend )
358 error = tt_face_vary_cvt( face, stream );
359 #endif
360
361 Exit:
362 return error;
363
364 #else /* !TT_USE_BYTECODE_INTERPRETER */
365
366 FT_UNUSED( face );
367 FT_UNUSED( stream );
368
369 return FT_Err_Ok;
370
371 #endif
372 }
373
374
375 /**************************************************************************
376 *
377 * @Function:
378 * tt_face_load_fpgm
379 *
380 * @Description:
381 * Load the font program.
382 *
383 * @InOut:
384 * face ::
385 * A handle to the target face object.
386 *
387 * @Input:
388 * stream ::
389 * A handle to the input stream.
390 *
391 * @Return:
392 * FreeType error code. 0 means success.
393 */
394 FT_LOCAL_DEF( FT_Error )
395 tt_face_load_fpgm( TT_Face face,
396 FT_Stream stream )
397 {
398 #ifdef TT_USE_BYTECODE_INTERPRETER
399
400 FT_Error error;
401 FT_ULong table_len;
402
403
404 FT_TRACE2(( "Font program " ));
405
406 /* The font program is optional */
407 error = face->goto_table( face, TTAG_fpgm, stream, &table_len );
408 if ( error )
409 {
410 face->font_program = NULL;
411 face->font_program_size = 0;
412 error = FT_Err_Ok;
413
414 FT_TRACE2(( "is missing\n" ));
415 }
416 else
417 {
418 face->font_program_size = table_len;
419 if ( FT_FRAME_EXTRACT( table_len, face->font_program ) )
420 goto Exit;
421
422 FT_TRACE2(( "loaded, %12ld bytes\n", face->font_program_size ));
423 }
424
425 Exit:
426 return error;
427
428 #else /* !TT_USE_BYTECODE_INTERPRETER */
429
430 FT_UNUSED( face );
431 FT_UNUSED( stream );
432
433 return FT_Err_Ok;
434
435 #endif
436 }
437
438
439 /**************************************************************************
440 *
441 * @Function:
442 * tt_face_load_prep
443 *
444 * @Description:
445 * Load the cvt program.
446 *
447 * @InOut:
448 * face ::
449 * A handle to the target face object.
450 *
451 * @Input:
452 * stream ::
453 * A handle to the input stream.
454 *
455 * @Return:
456 * FreeType error code. 0 means success.
457 */
458 FT_LOCAL_DEF( FT_Error )
459 tt_face_load_prep( TT_Face face,
460 FT_Stream stream )
461 {
462 #ifdef TT_USE_BYTECODE_INTERPRETER
463
464 FT_Error error;
465 FT_ULong table_len;
466
467
468 FT_TRACE2(( "Prep program " ));
469
470 error = face->goto_table( face, TTAG_prep, stream, &table_len );
471 if ( error )
472 {
473 face->cvt_program = NULL;
474 face->cvt_program_size = 0;
475 error = FT_Err_Ok;
476
477 FT_TRACE2(( "is missing\n" ));
478 }
479 else
480 {
481 face->cvt_program_size = table_len;
482 if ( FT_FRAME_EXTRACT( table_len, face->cvt_program ) )
483 goto Exit;
484
485 FT_TRACE2(( "loaded, %12ld bytes\n", face->cvt_program_size ));
486 }
487
488 Exit:
489 return error;
490
491 #else /* !TT_USE_BYTECODE_INTERPRETER */
492
493 FT_UNUSED( face );
494 FT_UNUSED( stream );
495
496 return FT_Err_Ok;
497
498 #endif
499 }
500
501
502 FT_COMPARE_DEF( int )
503 compare_ppem( const void* a,
504 const void* b )
505 {
506 return **(FT_Byte**)a - **(FT_Byte**)b;
507 }
508
509
510 /**************************************************************************
511 *
512 * @Function:
513 * tt_face_load_hdmx
514 *
515 * @Description:
516 * Load the `hdmx' table into the face object.
517 *
518 * @Input:
519 * face ::
520 * A handle to the target face object.
521 *
522 * stream ::
523 * A handle to the input stream.
524 *
525 * @Return:
526 * FreeType error code. 0 means success.
527 */
528
529 FT_LOCAL_DEF( FT_Error )
530 tt_face_load_hdmx( TT_Face face,
531 FT_Stream stream )
532 {
533 FT_Error error;
534 FT_Memory memory = stream->memory;
535 FT_UInt nn, num_records;
536 FT_ULong table_size, record_size;
537 FT_Byte* p;
538 FT_Byte* limit;
539
540
541 /* this table is optional */
542 error = face->goto_table( face, TTAG_hdmx, stream, &table_size );
543 if ( error || table_size < 8 )
544 return FT_Err_Ok;
545
546 if ( FT_FRAME_EXTRACT( table_size, face->hdmx_table ) )
547 goto Exit;
548
549 p = face->hdmx_table;
550 limit = p + table_size;
551
552 /* Given that `hdmx' tables are losing its importance (for example, */
553 /* variation fonts introduced in OpenType 1.8 must not have this */
554 /* table) we no longer test for a correct `version' field. */
555 p += 2;
556 num_records = FT_NEXT_USHORT( p );
557 record_size = FT_NEXT_ULONG( p );
558
559 /* There are at least two fonts, HANNOM-A and HANNOM-B version */
560 /* 2.0 (2005), which get this wrong: The upper two bytes of */
561 /* the size value are set to 0xFF instead of 0x00. We catch */
562 /* and fix this. */
563
564 if ( record_size >= 0xFFFF0000UL )
565 record_size &= 0xFFFFU;
566
567 FT_TRACE2(( "Hdmx " ));
568
569 /* The limit for `num_records' is a heuristic value. */
570 if ( num_records > 255 || num_records == 0 )
571 {
572 FT_TRACE2(( "with unreasonable %u records rejected\n", num_records ));
573 goto Fail;
574 }
575
576 /* Out-of-spec tables are rejected. The record size must be */
577 /* equal to the number of glyphs + 2 + 32-bit padding. */
578 if ( (FT_Long)record_size != ( ( face->root.num_glyphs + 2 + 3 ) & ~3 ) )
579 {
580 FT_TRACE2(( "with record size off by %ld bytes rejected\n",
581 (FT_Long)record_size -
582 ( ( face->root.num_glyphs + 2 + 3 ) & ~3 ) ));
583 goto Fail;
584 }
585
586 if ( FT_QNEW_ARRAY( face->hdmx_records, num_records ) )
587 goto Fail;
588
589 for ( nn = 0; nn < num_records; nn++ )
590 {
591 if ( p + record_size > limit )
592 break;
593 face->hdmx_records[nn] = p;
594 p += record_size;
595 }
596
597 /* The records must be already sorted by ppem but it does not */
598 /* hurt to make sure so that the binary search works later. */
599 ft_qsort( face->hdmx_records, nn, sizeof ( FT_Byte* ), compare_ppem );
600
601 face->hdmx_record_count = nn;
602 face->hdmx_table_size = table_size;
603 face->hdmx_record_size = record_size;
604
605 FT_TRACE2(( "%ux%lu loaded\n", num_records, record_size ));
606
607 Exit:
608 return error;
609
610 Fail:
611 FT_FRAME_RELEASE( face->hdmx_table );
612 face->hdmx_table_size = 0;
613 goto Exit;
614 }
615
616
617 FT_LOCAL_DEF( void )
618 tt_face_free_hdmx( TT_Face face )
619 {
620 FT_Stream stream = face->root.stream;
621 FT_Memory memory = stream->memory;
622
623
624 FT_FREE( face->hdmx_records );
625 FT_FRAME_RELEASE( face->hdmx_table );
626 }
627
628
629 /**************************************************************************
630 *
631 * Return the advance width table for a given pixel size if it is found
632 * in the font's `hdmx' table (if any). The records must be sorted for
633 * the binary search to work properly.
634 */
635 FT_LOCAL_DEF( FT_Byte* )
636 tt_face_get_device_metrics( TT_Face face,
637 FT_UInt ppem,
638 FT_UInt gindex )
639 {
640 FT_UInt min = 0;
641 FT_UInt max = face->hdmx_record_count;
642 FT_UInt mid;
643 FT_Byte* result = NULL;
644
645
646 while ( min < max )
647 {
648 mid = ( min + max ) >> 1;
649
650 if ( face->hdmx_records[mid][0] > ppem )
651 max = mid;
652 else if ( face->hdmx_records[mid][0] < ppem )
653 min = mid + 1;
654 else
655 {
656 result = face->hdmx_records[mid] + 2 + gindex;
657 break;
658 }
659 }
660
661 return result;
662 }
663
664
665 /* END */