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1 /*
2  * Copyright © 2007,2008,2009  Red Hat, Inc.
3  * Copyright © 2012  Google, Inc.
4  *
5  *  This is part of HarfBuzz, a text shaping library.
6  *
7  * Permission is hereby granted, without written agreement and without
8  * license or royalty fees, to use, copy, modify, and distribute this
9  * software and its documentation for any purpose, provided that the
10  * above copyright notice and the following two paragraphs appear in
11  * all copies of this software.
12  *
13  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
14  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
15  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
16  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
17  * DAMAGE.
18  *
19  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
20  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
22  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
23  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
24  *
25  * Red Hat Author(s): Behdad Esfahbod
26  * Google Author(s): Behdad Esfahbod
27  */
28 
29 #ifndef HB_OPEN_FILE_HH
30 #define HB_OPEN_FILE_HH
31 
32 #include "hb-open-type.hh"
33 #include "hb-ot-head-table.hh"
34 
35 
36 namespace OT {
37 
38 /*
39  *
40  * The OpenType Font File
41  *
42  */
43 
44 
45 /*
46  * Organization of an OpenType Font
47  */
48 
49 struct OpenTypeFontFile;
50 struct OpenTypeOffsetTable;
51 struct TTCHeader;
52 
53 
54 typedef struct TableRecord
55 {
cmpOT::TableRecord56   int cmp (Tag t) const { return -t.cmp (tag); }
57 
cmpOT::TableRecord58   HB_INTERNAL static int cmp (const void *pa, const void *pb)
59   {
60     const TableRecord *a = (const TableRecord *) pa;
61     const TableRecord *b = (const TableRecord *) pb;
62     return b->cmp (a->tag);
63   }
64 
sanitizeOT::TableRecord65   bool sanitize (hb_sanitize_context_t *c) const
66   {
67     TRACE_SANITIZE (this);
68     return_trace (c->check_struct (this));
69   }
70 
71   Tag		tag;		/* 4-byte identifier. */
72   CheckSum	checkSum;	/* CheckSum for this table. */
73   Offset32	offset;		/* Offset from beginning of TrueType font
74 				 * file. */
75   HBUINT32	length;		/* Length of this table. */
76   public:
77   DEFINE_SIZE_STATIC (16);
78 } OpenTypeTable;
79 
80 typedef struct OpenTypeOffsetTable
81 {
82   friend struct OpenTypeFontFile;
83 
get_table_countOT::OpenTypeOffsetTable84   unsigned int get_table_count () const { return tables.len; }
get_tableOT::OpenTypeOffsetTable85   const TableRecord& get_table (unsigned int i) const
86   { return tables[i]; }
get_table_tagsOT::OpenTypeOffsetTable87   unsigned int get_table_tags (unsigned int  start_offset,
88 			       unsigned int *table_count, /* IN/OUT */
89 			       hb_tag_t     *table_tags /* OUT */) const
90   {
91     if (table_count)
92     {
93       + tables.as_array ().sub_array (start_offset, table_count)
94       | hb_map (&TableRecord::tag)
95       | hb_sink (hb_array (table_tags, *table_count))
96       ;
97     }
98     return tables.len;
99   }
find_table_indexOT::OpenTypeOffsetTable100   bool find_table_index (hb_tag_t tag, unsigned int *table_index) const
101   {
102     Tag t;
103     t = tag;
104     /* Use lfind for small fonts; there are fonts that have unsorted table entries;
105      * those tend to work in other tools, so tolerate them.
106      * https://github.com/harfbuzz/harfbuzz/issues/3065 */
107     if (tables.len < 16)
108       return tables.lfind (t, table_index, HB_NOT_FOUND_STORE, Index::NOT_FOUND_INDEX);
109     else
110       return tables.bfind (t, table_index, HB_NOT_FOUND_STORE, Index::NOT_FOUND_INDEX);
111   }
get_table_by_tagOT::OpenTypeOffsetTable112   const TableRecord& get_table_by_tag (hb_tag_t tag) const
113   {
114     unsigned int table_index;
115     find_table_index (tag, &table_index);
116     return get_table (table_index);
117   }
118 
119   public:
120 
121   template <typename Iterator,
122 	    hb_requires ((hb_is_source_of<Iterator, hb_pair_t<hb_tag_t, hb_blob_t *>>::value))>
serializeOT::OpenTypeOffsetTable123   bool serialize (hb_serialize_context_t *c,
124 		  hb_tag_t sfnt_tag,
125 		  Iterator it)
126   {
127     TRACE_SERIALIZE (this);
128     /* Alloc 12 for the OTHeader. */
129     if (unlikely (!c->extend_min (this))) return_trace (false);
130     /* Write sfntVersion (bytes 0..3). */
131     sfnt_version = sfnt_tag;
132     /* Take space for numTables, searchRange, entrySelector, RangeShift
133      * and the TableRecords themselves.  */
134     unsigned num_items = it.len ();
135     if (unlikely (!tables.serialize (c, num_items))) return_trace (false);
136 
137     const char *dir_end = (const char *) c->head;
138     HBUINT32 *checksum_adjustment = nullptr;
139 
140     /* Write OffsetTables, alloc for and write actual table blobs. */
141     unsigned i = 0;
142     for (hb_pair_t<hb_tag_t, hb_blob_t*> entry : it)
143     {
144       hb_blob_t *blob = entry.second;
145       unsigned len = blob->length;
146 
147       /* Allocate room for the table and copy it. */
148       char *start = (char *) c->allocate_size<void> (len);
149       if (unlikely (!start)) return false;
150 
151       TableRecord &rec = tables.arrayZ[i];
152       rec.tag = entry.first;
153       rec.length = len;
154       rec.offset = 0;
155       if (unlikely (!c->check_assign (rec.offset,
156 				      (unsigned) ((char *) start - (char *) this),
157 				      HB_SERIALIZE_ERROR_OFFSET_OVERFLOW)))
158         return_trace (false);
159 
160       if (likely (len))
161 	hb_memcpy (start, blob->data, len);
162 
163       /* 4-byte alignment. */
164       c->align (4);
165       const char *end = (const char *) c->head;
166 
167       if (entry.first == HB_OT_TAG_head &&
168 	  (unsigned) (end - start) >= head::static_size)
169       {
170 	head *h = (head *) start;
171 	checksum_adjustment = &h->checkSumAdjustment;
172 	*checksum_adjustment = 0;
173       }
174 
175       rec.checkSum.set_for_data (start, end - start);
176       i++;
177     }
178 
179     tables.qsort ();
180 
181     if (checksum_adjustment)
182     {
183       CheckSum checksum;
184 
185       /* The following line is a slower version of the following block. */
186       //checksum.set_for_data (this, (const char *) c->head - (const char *) this);
187       checksum.set_for_data (this, dir_end - (const char *) this);
188       for (unsigned int i = 0; i < num_items; i++)
189       {
190 	TableRecord &rec = tables.arrayZ[i];
191 	checksum = checksum + rec.checkSum;
192       }
193 
194       *checksum_adjustment = 0xB1B0AFBAu - checksum;
195     }
196 
197     return_trace (true);
198   }
199 
sanitizeOT::OpenTypeOffsetTable200   bool sanitize (hb_sanitize_context_t *c) const
201   {
202     TRACE_SANITIZE (this);
203     return_trace (c->check_struct (this) && tables.sanitize (c));
204   }
205 
206   protected:
207   Tag		sfnt_version;	/* '\0\001\0\00' if TrueType / 'OTTO' if CFF */
208   BinSearchArrayOf<TableRecord>
209 		tables;
210   public:
211   DEFINE_SIZE_ARRAY (12, tables);
212 } OpenTypeFontFace;
213 
214 
215 /*
216  * TrueType Collections
217  */
218 
219 struct TTCHeaderVersion1
220 {
221   friend struct TTCHeader;
222 
get_face_countOT::TTCHeaderVersion1223   unsigned int get_face_count () const { return table.len; }
get_faceOT::TTCHeaderVersion1224   const OpenTypeFontFace& get_face (unsigned int i) const { return this+table[i]; }
225 
sanitizeOT::TTCHeaderVersion1226   bool sanitize (hb_sanitize_context_t *c) const
227   {
228     TRACE_SANITIZE (this);
229     return_trace (table.sanitize (c, this));
230   }
231 
232   protected:
233   Tag		ttcTag;		/* TrueType Collection ID string: 'ttcf' */
234   FixedVersion<>version;	/* Version of the TTC Header (1.0),
235 				 * 0x00010000u */
236   Array32Of<Offset32To<OpenTypeOffsetTable>>
237 		table;		/* Array of offsets to the OffsetTable for each font
238 				 * from the beginning of the file */
239   public:
240   DEFINE_SIZE_ARRAY (12, table);
241 };
242 
243 struct TTCHeader
244 {
245   friend struct OpenTypeFontFile;
246 
247   private:
248 
get_face_countOT::TTCHeader249   unsigned int get_face_count () const
250   {
251     switch (u.header.version.major) {
252     case 2: /* version 2 is compatible with version 1 */
253     case 1: return u.version1.get_face_count ();
254     default:return 0;
255     }
256   }
get_faceOT::TTCHeader257   const OpenTypeFontFace& get_face (unsigned int i) const
258   {
259     switch (u.header.version.major) {
260     case 2: /* version 2 is compatible with version 1 */
261     case 1: return u.version1.get_face (i);
262     default:return Null (OpenTypeFontFace);
263     }
264   }
265 
sanitizeOT::TTCHeader266   bool sanitize (hb_sanitize_context_t *c) const
267   {
268     TRACE_SANITIZE (this);
269     if (unlikely (!u.header.version.sanitize (c))) return_trace (false);
270     switch (u.header.version.major) {
271     case 2: /* version 2 is compatible with version 1 */
272     case 1: return_trace (u.version1.sanitize (c));
273     default:return_trace (true);
274     }
275   }
276 
277   protected:
278   union {
279   struct {
280   Tag		ttcTag;		/* TrueType Collection ID string: 'ttcf' */
281   FixedVersion<>version;	/* Version of the TTC Header (1.0 or 2.0),
282 				 * 0x00010000u or 0x00020000u */
283   }			header;
284   TTCHeaderVersion1	version1;
285   } u;
286 };
287 
288 /*
289  * Mac Resource Fork
290  *
291  * http://mirror.informatimago.com/next/developer.apple.com/documentation/mac/MoreToolbox/MoreToolbox-99.html
292  */
293 
294 struct ResourceRecord
295 {
get_faceOT::ResourceRecord296   const OpenTypeFontFace & get_face (const void *data_base) const
297   { return * reinterpret_cast<const OpenTypeFontFace *> ((data_base+offset).arrayZ); }
298 
sanitizeOT::ResourceRecord299   bool sanitize (hb_sanitize_context_t *c,
300 		 const void *data_base) const
301   {
302     TRACE_SANITIZE (this);
303     return_trace (c->check_struct (this) &&
304 		  offset.sanitize (c, data_base) &&
305 		  get_face (data_base).sanitize (c));
306   }
307 
308   protected:
309   HBUINT16	id;		/* Resource ID. */
310   HBINT16	nameOffset;	/* Offset from beginning of resource name list
311 				 * to resource name, -1 means there is none. */
312   HBUINT8	attrs;		/* Resource attributes */
313   NNOffset24To<Array32Of<HBUINT8>>
314 		offset;		/* Offset from beginning of data block to
315 				 * data for this resource */
316   HBUINT32	reserved;	/* Reserved for handle to resource */
317   public:
318   DEFINE_SIZE_STATIC (12);
319 };
320 
321 #define HB_TAG_sfnt HB_TAG ('s','f','n','t')
322 
323 struct ResourceTypeRecord
324 {
get_resource_countOT::ResourceTypeRecord325   unsigned int get_resource_count () const
326   { return tag == HB_TAG_sfnt ? resCountM1 + 1 : 0; }
327 
is_sfntOT::ResourceTypeRecord328   bool is_sfnt () const { return tag == HB_TAG_sfnt; }
329 
get_resource_recordOT::ResourceTypeRecord330   const ResourceRecord& get_resource_record (unsigned int i,
331 					     const void *type_base) const
332   { return (type_base+resourcesZ).as_array (get_resource_count ())[i]; }
333 
sanitizeOT::ResourceTypeRecord334   bool sanitize (hb_sanitize_context_t *c,
335 		 const void *type_base,
336 		 const void *data_base) const
337   {
338     TRACE_SANITIZE (this);
339     return_trace (c->check_struct (this) &&
340 		  resourcesZ.sanitize (c, type_base,
341 				       get_resource_count (),
342 				       data_base));
343   }
344 
345   protected:
346   Tag		tag;		/* Resource type. */
347   HBUINT16	resCountM1;	/* Number of resources minus 1. */
348   NNOffset16To<UnsizedArrayOf<ResourceRecord>>
349 		resourcesZ;	/* Offset from beginning of resource type list
350 				 * to reference item list for this type. */
351   public:
352   DEFINE_SIZE_STATIC (8);
353 };
354 
355 struct ResourceMap
356 {
get_face_countOT::ResourceMap357   unsigned int get_face_count () const
358   {
359     unsigned int count = get_type_count ();
360     for (unsigned int i = 0; i < count; i++)
361     {
362       const ResourceTypeRecord& type = get_type_record (i);
363       if (type.is_sfnt ())
364 	return type.get_resource_count ();
365     }
366     return 0;
367   }
368 
get_faceOT::ResourceMap369   const OpenTypeFontFace& get_face (unsigned int idx,
370 				    const void *data_base) const
371   {
372     unsigned int count = get_type_count ();
373     for (unsigned int i = 0; i < count; i++)
374     {
375       const ResourceTypeRecord& type = get_type_record (i);
376       /* The check for idx < count is here because ResourceRecord is NOT null-safe.
377        * Because an offset of 0 there does NOT mean null. */
378       if (type.is_sfnt () && idx < type.get_resource_count ())
379 	return type.get_resource_record (idx, &(this+typeList)).get_face (data_base);
380     }
381     return Null (OpenTypeFontFace);
382   }
383 
sanitizeOT::ResourceMap384   bool sanitize (hb_sanitize_context_t *c, const void *data_base) const
385   {
386     TRACE_SANITIZE (this);
387     return_trace (c->check_struct (this) &&
388 		  typeList.sanitize (c, this,
389 				     &(this+typeList),
390 				     data_base));
391   }
392 
393   private:
get_type_countOT::ResourceMap394   unsigned int get_type_count () const { return (this+typeList).lenM1 + 1; }
395 
get_type_recordOT::ResourceMap396   const ResourceTypeRecord& get_type_record (unsigned int i) const
397   { return (this+typeList)[i]; }
398 
399   protected:
400   HBUINT8	reserved0[16];	/* Reserved for copy of resource header */
401   HBUINT32	reserved1;	/* Reserved for handle to next resource map */
402   HBUINT16	resreved2;	/* Reserved for file reference number */
403   HBUINT16	attrs;		/* Resource fork attribute */
404   NNOffset16To<ArrayOfM1<ResourceTypeRecord>>
405 		typeList;	/* Offset from beginning of map to
406 				 * resource type list */
407   Offset16	nameList;	/* Offset from beginning of map to
408 				 * resource name list */
409   public:
410   DEFINE_SIZE_STATIC (28);
411 };
412 
413 struct ResourceForkHeader
414 {
get_face_countOT::ResourceForkHeader415   unsigned int get_face_count () const
416   { return (this+map).get_face_count (); }
417 
get_faceOT::ResourceForkHeader418   const OpenTypeFontFace& get_face (unsigned int idx,
419 				    unsigned int *base_offset = nullptr) const
420   {
421     const OpenTypeFontFace &face = (this+map).get_face (idx, &(this+data));
422     if (base_offset)
423       *base_offset = (const char *) &face - (const char *) this;
424     return face;
425   }
426 
sanitizeOT::ResourceForkHeader427   bool sanitize (hb_sanitize_context_t *c) const
428   {
429     TRACE_SANITIZE (this);
430     return_trace (c->check_struct (this) &&
431 		  data.sanitize (c, this, dataLen) &&
432 		  map.sanitize (c, this, &(this+data)));
433   }
434 
435   protected:
436   NNOffset32To<UnsizedArrayOf<HBUINT8>>
437 		data;		/* Offset from beginning of resource fork
438 				 * to resource data */
439   NNOffset32To<ResourceMap >
440 		map;		/* Offset from beginning of resource fork
441 				 * to resource map */
442   HBUINT32	dataLen;	/* Length of resource data */
443   HBUINT32	mapLen;		/* Length of resource map */
444   public:
445   DEFINE_SIZE_STATIC (16);
446 };
447 
448 /*
449  * OpenType Font File
450  */
451 
452 struct OpenTypeFontFile
453 {
454   enum {
455     CFFTag		= HB_TAG ('O','T','T','O'), /* OpenType with Postscript outlines */
456     TrueTypeTag		= HB_TAG ( 0 , 1 , 0 , 0 ), /* OpenType with TrueType outlines */
457     TTCTag		= HB_TAG ('t','t','c','f'), /* TrueType Collection */
458     DFontTag		= HB_TAG ( 0 , 0 , 1 , 0 ), /* DFont Mac Resource Fork */
459     TrueTag		= HB_TAG ('t','r','u','e'), /* Obsolete Apple TrueType */
460     Typ1Tag		= HB_TAG ('t','y','p','1')  /* Obsolete Apple Type1 font in SFNT container */
461   };
462 
get_tagOT::OpenTypeFontFile463   hb_tag_t get_tag () const { return u.tag; }
464 
get_face_countOT::OpenTypeFontFile465   unsigned int get_face_count () const
466   {
467     switch (u.tag) {
468     case CFFTag:	/* All the non-collection tags */
469     case TrueTag:
470     case Typ1Tag:
471     case TrueTypeTag:	return 1;
472     case TTCTag:	return u.ttcHeader.get_face_count ();
473     case DFontTag:	return u.rfHeader.get_face_count ();
474     default:		return 0;
475     }
476   }
get_faceOT::OpenTypeFontFile477   const OpenTypeFontFace& get_face (unsigned int i, unsigned int *base_offset = nullptr) const
478   {
479     if (base_offset)
480       *base_offset = 0;
481     switch (u.tag) {
482     /* Note: for non-collection SFNT data we ignore index.  This is because
483      * Apple dfont container is a container of SFNT's.  So each SFNT is a
484      * non-TTC, but the index is more than zero. */
485     case CFFTag:	/* All the non-collection tags */
486     case TrueTag:
487     case Typ1Tag:
488     case TrueTypeTag:	return u.fontFace;
489     case TTCTag:	return u.ttcHeader.get_face (i);
490     case DFontTag:	return u.rfHeader.get_face (i, base_offset);
491     default:		return Null (OpenTypeFontFace);
492     }
493   }
494 
495   template <typename Iterator,
496 	    hb_requires ((hb_is_source_of<Iterator, hb_pair_t<hb_tag_t, hb_blob_t *>>::value))>
serialize_singleOT::OpenTypeFontFile497   bool serialize_single (hb_serialize_context_t *c,
498 			 hb_tag_t sfnt_tag,
499 			 Iterator items)
500   {
501     TRACE_SERIALIZE (this);
502     assert (sfnt_tag != TTCTag);
503     if (unlikely (!c->extend_min (this))) return_trace (false);
504     return_trace (u.fontFace.serialize (c, sfnt_tag, items));
505   }
506 
sanitizeOT::OpenTypeFontFile507   bool sanitize (hb_sanitize_context_t *c) const
508   {
509     TRACE_SANITIZE (this);
510     if (unlikely (!u.tag.sanitize (c))) return_trace (false);
511     switch (u.tag) {
512     case CFFTag:	/* All the non-collection tags */
513     case TrueTag:
514     case Typ1Tag:
515     case TrueTypeTag:	return_trace (u.fontFace.sanitize (c));
516     case TTCTag:	return_trace (u.ttcHeader.sanitize (c));
517     case DFontTag:	return_trace (u.rfHeader.sanitize (c));
518     default:		return_trace (true);
519     }
520   }
521 
522   protected:
523   union {
524   Tag			tag;		/* 4-byte identifier. */
525   OpenTypeFontFace	fontFace;
526   TTCHeader		ttcHeader;
527   ResourceForkHeader	rfHeader;
528   } u;
529   public:
530   DEFINE_SIZE_UNION (4, tag);
531 };
532 
533 
534 } /* namespace OT */
535 
536 
537 #endif /* HB_OPEN_FILE_HH */
538