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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_PRIVATE_HH
30 #define HB_OPEN_FILE_PRIVATE_HH
31 
32 #include "hb-open-type-private.hh"
33 
34 
35 namespace OT {
36 
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 OffsetTable;
51 struct TTCHeader;
52 
53 
54 typedef struct TableRecord
55 {
sanitizeOT::TableRecord56   inline bool sanitize (hb_sanitize_context_t *c) const
57   {
58     TRACE_SANITIZE (this);
59     return_trace (c->check_struct (this));
60   }
61 
62   Tag		tag;		/* 4-byte identifier. */
63   CheckSum	checkSum;	/* CheckSum for this table. */
64   ULONG		offset;		/* Offset from beginning of TrueType font
65 				 * file. */
66   ULONG		length;		/* Length of this table. */
67   public:
68   DEFINE_SIZE_STATIC (16);
69 } OpenTypeTable;
70 
71 typedef struct OffsetTable
72 {
73   friend struct OpenTypeFontFile;
74 
get_table_countOT::OffsetTable75   inline unsigned int get_table_count (void) const
76   { return numTables; }
get_tableOT::OffsetTable77   inline const TableRecord& get_table (unsigned int i) const
78   {
79     if (unlikely (i >= numTables)) return Null(TableRecord);
80     return tables[i];
81   }
find_table_indexOT::OffsetTable82   inline bool find_table_index (hb_tag_t tag, unsigned int *table_index) const
83   {
84     Tag t;
85     t.set (tag);
86     unsigned int count = numTables;
87     for (unsigned int i = 0; i < count; i++)
88     {
89       if (t == tables[i].tag)
90       {
91         if (table_index) *table_index = i;
92         return true;
93       }
94     }
95     if (table_index) *table_index = Index::NOT_FOUND_INDEX;
96     return false;
97   }
get_table_by_tagOT::OffsetTable98   inline const TableRecord& get_table_by_tag (hb_tag_t tag) const
99   {
100     unsigned int table_index;
101     find_table_index (tag, &table_index);
102     return get_table (table_index);
103   }
104 
105   public:
sanitizeOT::OffsetTable106   inline bool sanitize (hb_sanitize_context_t *c) const
107   {
108     TRACE_SANITIZE (this);
109     return_trace (c->check_struct (this) && c->check_array (tables, TableRecord::static_size, numTables));
110   }
111 
112   protected:
113   Tag		sfnt_version;	/* '\0\001\0\00' if TrueType / 'OTTO' if CFF */
114   USHORT	numTables;	/* Number of tables. */
115   USHORT	searchRangeZ;	/* (Maximum power of 2 <= numTables) x 16 */
116   USHORT	entrySelectorZ;	/* Log2(maximum power of 2 <= numTables). */
117   USHORT	rangeShiftZ;	/* NumTables x 16-searchRange. */
118   TableRecord	tables[VAR];	/* TableRecord entries. numTables items */
119   public:
120   DEFINE_SIZE_ARRAY (12, tables);
121 } OpenTypeFontFace;
122 
123 
124 /*
125  * TrueType Collections
126  */
127 
128 struct TTCHeaderVersion1
129 {
130   friend struct TTCHeader;
131 
get_face_countOT::TTCHeaderVersion1132   inline unsigned int get_face_count (void) const { return table.len; }
get_faceOT::TTCHeaderVersion1133   inline const OpenTypeFontFace& get_face (unsigned int i) const { return this+table[i]; }
134 
sanitizeOT::TTCHeaderVersion1135   inline bool sanitize (hb_sanitize_context_t *c) const
136   {
137     TRACE_SANITIZE (this);
138     return_trace (table.sanitize (c, this));
139   }
140 
141   protected:
142   Tag		ttcTag;		/* TrueType Collection ID string: 'ttcf' */
143   FixedVersion<>version;	/* Version of the TTC Header (1.0),
144 				 * 0x00010000u */
145   ArrayOf<LOffsetTo<OffsetTable>, ULONG>
146 		table;		/* Array of offsets to the OffsetTable for each font
147 				 * from the beginning of the file */
148   public:
149   DEFINE_SIZE_ARRAY (12, table);
150 };
151 
152 struct TTCHeader
153 {
154   friend struct OpenTypeFontFile;
155 
156   private:
157 
get_face_countOT::TTCHeader158   inline unsigned int get_face_count (void) const
159   {
160     switch (u.header.version.major) {
161     case 2: /* version 2 is compatible with version 1 */
162     case 1: return u.version1.get_face_count ();
163     default:return 0;
164     }
165   }
get_faceOT::TTCHeader166   inline const OpenTypeFontFace& get_face (unsigned int i) const
167   {
168     switch (u.header.version.major) {
169     case 2: /* version 2 is compatible with version 1 */
170     case 1: return u.version1.get_face (i);
171     default:return Null(OpenTypeFontFace);
172     }
173   }
174 
sanitizeOT::TTCHeader175   inline bool sanitize (hb_sanitize_context_t *c) const
176   {
177     TRACE_SANITIZE (this);
178     if (unlikely (!u.header.version.sanitize (c))) return_trace (false);
179     switch (u.header.version.major) {
180     case 2: /* version 2 is compatible with version 1 */
181     case 1: return_trace (u.version1.sanitize (c));
182     default:return_trace (true);
183     }
184   }
185 
186   protected:
187   union {
188   struct {
189   Tag		ttcTag;		/* TrueType Collection ID string: 'ttcf' */
190   FixedVersion<>version;	/* Version of the TTC Header (1.0 or 2.0),
191 				 * 0x00010000u or 0x00020000u */
192   }			header;
193   TTCHeaderVersion1	version1;
194   } u;
195 };
196 
197 
198 /*
199  * OpenType Font File
200  */
201 
202 struct OpenTypeFontFile
203 {
204   static const hb_tag_t tableTag	= HB_TAG ('_','_','_','_'); /* Sanitizer needs this. */
205 
206   static const hb_tag_t CFFTag		= HB_TAG ('O','T','T','O'); /* OpenType with Postscript outlines */
207   static const hb_tag_t TrueTypeTag	= HB_TAG ( 0 , 1 , 0 , 0 ); /* OpenType with TrueType outlines */
208   static const hb_tag_t TTCTag		= HB_TAG ('t','t','c','f'); /* TrueType Collection */
209   static const hb_tag_t TrueTag		= HB_TAG ('t','r','u','e'); /* Obsolete Apple TrueType */
210   static const hb_tag_t Typ1Tag		= HB_TAG ('t','y','p','1'); /* Obsolete Apple Type1 font in SFNT container */
211 
get_tagOT::OpenTypeFontFile212   inline hb_tag_t get_tag (void) const { return u.tag; }
213 
get_face_countOT::OpenTypeFontFile214   inline unsigned int get_face_count (void) const
215   {
216     switch (u.tag) {
217     case CFFTag:	/* All the non-collection tags */
218     case TrueTag:
219     case Typ1Tag:
220     case TrueTypeTag:	return 1;
221     case TTCTag:	return u.ttcHeader.get_face_count ();
222     default:		return 0;
223     }
224   }
get_faceOT::OpenTypeFontFile225   inline const OpenTypeFontFace& get_face (unsigned int i) const
226   {
227     switch (u.tag) {
228     /* Note: for non-collection SFNT data we ignore index.  This is because
229      * Apple dfont container is a container of SFNT's.  So each SFNT is a
230      * non-TTC, but the index is more than zero. */
231     case CFFTag:	/* All the non-collection tags */
232     case TrueTag:
233     case Typ1Tag:
234     case TrueTypeTag:	return u.fontFace;
235     case TTCTag:	return u.ttcHeader.get_face (i);
236     default:		return Null(OpenTypeFontFace);
237     }
238   }
239 
sanitizeOT::OpenTypeFontFile240   inline bool sanitize (hb_sanitize_context_t *c) const
241   {
242     TRACE_SANITIZE (this);
243     if (unlikely (!u.tag.sanitize (c))) return_trace (false);
244     switch (u.tag) {
245     case CFFTag:	/* All the non-collection tags */
246     case TrueTag:
247     case Typ1Tag:
248     case TrueTypeTag:	return_trace (u.fontFace.sanitize (c));
249     case TTCTag:	return_trace (u.ttcHeader.sanitize (c));
250     default:		return_trace (true);
251     }
252   }
253 
254   protected:
255   union {
256   Tag			tag;		/* 4-byte identifier. */
257   OpenTypeFontFace	fontFace;
258   TTCHeader		ttcHeader;
259   } u;
260   public:
261   DEFINE_SIZE_UNION (4, tag);
262 };
263 
264 
265 } /* namespace OT */
266 
267 
268 #endif /* HB_OPEN_FILE_PRIVATE_HH */
269