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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) {
57     TRACE_SANITIZE (this);
58     return TRACE_RETURN (c->check_struct (this));
59   }
60 
61   Tag		tag;		/* 4-byte identifier. */
62   CheckSum	checkSum;	/* CheckSum for this table. */
63   ULONG		offset;		/* Offset from beginning of TrueType font
64 				 * file. */
65   ULONG		length;		/* Length of this table. */
66   public:
67   DEFINE_SIZE_STATIC (16);
68 } OpenTypeTable;
69 
70 typedef struct OffsetTable
71 {
72   friend struct OpenTypeFontFile;
73 
get_table_countOT::OffsetTable74   inline unsigned int get_table_count (void) const
75   { return numTables; }
get_tableOT::OffsetTable76   inline const TableRecord& get_table (unsigned int i) const
77   {
78     if (unlikely (i >= numTables)) return Null(TableRecord);
79     return tables[i];
80   }
find_table_indexOT::OffsetTable81   inline bool find_table_index (hb_tag_t tag, unsigned int *table_index) const
82   {
83     Tag t;
84     t.set (tag);
85     unsigned int count = numTables;
86     for (unsigned int i = 0; i < count; i++)
87     {
88       if (t == tables[i].tag)
89       {
90         if (table_index) *table_index = i;
91         return true;
92       }
93     }
94     if (table_index) *table_index = Index::NOT_FOUND_INDEX;
95     return false;
96   }
get_table_by_tagOT::OffsetTable97   inline const TableRecord& get_table_by_tag (hb_tag_t tag) const
98   {
99     unsigned int table_index;
100     find_table_index (tag, &table_index);
101     return get_table (table_index);
102   }
103 
104   public:
sanitizeOT::OffsetTable105   inline bool sanitize (hb_sanitize_context_t *c) {
106     TRACE_SANITIZE (this);
107     return TRACE_RETURN (c->check_struct (this) && c->check_array (tables, TableRecord::static_size, numTables));
108   }
109 
110   protected:
111   Tag		sfnt_version;	/* '\0\001\0\00' if TrueType / 'OTTO' if CFF */
112   USHORT	numTables;	/* Number of tables. */
113   USHORT	searchRange;	/* (Maximum power of 2 <= numTables) x 16 */
114   USHORT	entrySelector;	/* Log2(maximum power of 2 <= numTables). */
115   USHORT	rangeShift;	/* NumTables x 16-searchRange. */
116   TableRecord	tables[VAR];	/* TableRecord entries. numTables items */
117   public:
118   DEFINE_SIZE_ARRAY (12, tables);
119 } OpenTypeFontFace;
120 
121 
122 /*
123  * TrueType Collections
124  */
125 
126 struct TTCHeaderVersion1
127 {
128   friend struct TTCHeader;
129 
get_face_countOT::TTCHeaderVersion1130   inline unsigned int get_face_count (void) const { return table.len; }
get_faceOT::TTCHeaderVersion1131   inline const OpenTypeFontFace& get_face (unsigned int i) const { return this+table[i]; }
132 
sanitizeOT::TTCHeaderVersion1133   inline bool sanitize (hb_sanitize_context_t *c) {
134     TRACE_SANITIZE (this);
135     return TRACE_RETURN (table.sanitize (c, this));
136   }
137 
138   protected:
139   Tag		ttcTag;		/* TrueType Collection ID string: 'ttcf' */
140   FixedVersion	version;	/* Version of the TTC Header (1.0),
141 				 * 0x00010000 */
142   LongOffsetLongArrayOf<OffsetTable>
143 		table;		/* Array of offsets to the OffsetTable for each font
144 				 * from the beginning of the file */
145   public:
146   DEFINE_SIZE_ARRAY (12, table);
147 };
148 
149 struct TTCHeader
150 {
151   friend struct OpenTypeFontFile;
152 
153   private:
154 
get_face_countOT::TTCHeader155   inline unsigned int get_face_count (void) const
156   {
157     switch (u.header.version.major) {
158     case 2: /* version 2 is compatible with version 1 */
159     case 1: return u.version1.get_face_count ();
160     default:return 0;
161     }
162   }
get_faceOT::TTCHeader163   inline const OpenTypeFontFace& get_face (unsigned int i) const
164   {
165     switch (u.header.version.major) {
166     case 2: /* version 2 is compatible with version 1 */
167     case 1: return u.version1.get_face (i);
168     default:return Null(OpenTypeFontFace);
169     }
170   }
171 
sanitizeOT::TTCHeader172   inline bool sanitize (hb_sanitize_context_t *c) {
173     TRACE_SANITIZE (this);
174     if (unlikely (!u.header.version.sanitize (c))) return TRACE_RETURN (false);
175     switch (u.header.version.major) {
176     case 2: /* version 2 is compatible with version 1 */
177     case 1: return TRACE_RETURN (u.version1.sanitize (c));
178     default:return TRACE_RETURN (true);
179     }
180   }
181 
182   protected:
183   union {
184   struct {
185   Tag		ttcTag;		/* TrueType Collection ID string: 'ttcf' */
186   FixedVersion	version;	/* Version of the TTC Header (1.0 or 2.0),
187 				 * 0x00010000 or 0x00020000 */
188   }			header;
189   TTCHeaderVersion1	version1;
190   } u;
191 };
192 
193 
194 /*
195  * OpenType Font File
196  */
197 
198 struct OpenTypeFontFile
199 {
200   static const hb_tag_t CFFTag		= HB_TAG ('O','T','T','O'); /* OpenType with Postscript outlines */
201   static const hb_tag_t TrueTypeTag	= HB_TAG ( 0 , 1 , 0 , 0 ); /* OpenType with TrueType outlines */
202   static const hb_tag_t TTCTag		= HB_TAG ('t','t','c','f'); /* TrueType Collection */
203   static const hb_tag_t TrueTag		= HB_TAG ('t','r','u','e'); /* Obsolete Apple TrueType */
204   static const hb_tag_t Typ1Tag		= HB_TAG ('t','y','p','1'); /* Obsolete Apple Type1 font in SFNT container */
205 
get_tagOT::OpenTypeFontFile206   inline hb_tag_t get_tag (void) const { return u.tag; }
207 
get_face_countOT::OpenTypeFontFile208   inline unsigned int get_face_count (void) const
209   {
210     switch (u.tag) {
211     case CFFTag:	/* All the non-collection tags */
212     case TrueTag:
213     case Typ1Tag:
214     case TrueTypeTag:	return 1;
215     case TTCTag:	return u.ttcHeader.get_face_count ();
216     default:		return 0;
217     }
218   }
get_faceOT::OpenTypeFontFile219   inline const OpenTypeFontFace& get_face (unsigned int i) const
220   {
221     switch (u.tag) {
222     /* Note: for non-collection SFNT data we ignore index.  This is because
223      * Apple dfont container is a container of SFNT's.  So each SFNT is a
224      * non-TTC, but the index is more than zero. */
225     case CFFTag:	/* All the non-collection tags */
226     case TrueTag:
227     case Typ1Tag:
228     case TrueTypeTag:	return u.fontFace;
229     case TTCTag:	return u.ttcHeader.get_face (i);
230     default:		return Null(OpenTypeFontFace);
231     }
232   }
233 
sanitizeOT::OpenTypeFontFile234   inline bool sanitize (hb_sanitize_context_t *c) {
235     TRACE_SANITIZE (this);
236     if (unlikely (!u.tag.sanitize (c))) return TRACE_RETURN (false);
237     switch (u.tag) {
238     case CFFTag:	/* All the non-collection tags */
239     case TrueTag:
240     case Typ1Tag:
241     case TrueTypeTag:	return TRACE_RETURN (u.fontFace.sanitize (c));
242     case TTCTag:	return TRACE_RETURN (u.ttcHeader.sanitize (c));
243     default:		return TRACE_RETURN (true);
244     }
245   }
246 
247   protected:
248   union {
249   Tag			tag;		/* 4-byte identifier. */
250   OpenTypeFontFace	fontFace;
251   TTCHeader		ttcHeader;
252   } u;
253   public:
254   DEFINE_SIZE_UNION (4, tag);
255 };
256 
257 
258 } /* namespace OT */
259 
260 
261 #endif /* HB_OPEN_FILE_PRIVATE_HH */
262