1 /****************************************************************************
2 *
3 * gxvprop.c
4 *
5 * TrueTypeGX/AAT prop table validation (body).
6 *
7 * Copyright (C) 2004-2023 by
8 * suzuki toshiya, Masatake YAMATO, Red Hat K.K.,
9 * David Turner, Robert Wilhelm, and Werner Lemberg.
10 *
11 * This file is part of the FreeType project, and may only be used,
12 * modified, and distributed under the terms of the FreeType project
13 * license, LICENSE.TXT. By continuing to use, modify, or distribute
14 * this file you indicate that you have read the license and
15 * understand and accept it fully.
16 *
17 */
18
19 /****************************************************************************
20 *
21 * gxvalid is derived from both gxlayout module and otvalid module.
22 * Development of gxlayout is supported by the Information-technology
23 * Promotion Agency(IPA), Japan.
24 *
25 */
26
27
28 #include "gxvalid.h"
29 #include "gxvcommn.h"
30
31
32 /**************************************************************************
33 *
34 * The macro FT_COMPONENT is used in trace mode. It is an implicit
35 * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
36 * messages during execution.
37 */
38 #undef FT_COMPONENT
39 #define FT_COMPONENT gxvprop
40
41
42 /*************************************************************************/
43 /*************************************************************************/
44 /***** *****/
45 /***** Data and Types *****/
46 /***** *****/
47 /*************************************************************************/
48 /*************************************************************************/
49
50 #define GXV_PROP_HEADER_SIZE ( 4 + 2 + 2 )
51 #define GXV_PROP_SIZE_MIN GXV_PROP_HEADER_SIZE
52
53 typedef struct GXV_prop_DataRec_
54 {
55 FT_Fixed version;
56
57 } GXV_prop_DataRec, *GXV_prop_Data;
58
59 #define GXV_PROP_DATA( field ) GXV_TABLE_DATA( prop, field )
60
61 #define GXV_PROP_FLOATER 0x8000U
62 #define GXV_PROP_USE_COMPLEMENTARY_BRACKET 0x1000U
63 #define GXV_PROP_COMPLEMENTARY_BRACKET_OFFSET 0x0F00U
64 #define GXV_PROP_ATTACHING_TO_RIGHT 0x0080U
65 #define GXV_PROP_RESERVED 0x0060U
66 #define GXV_PROP_DIRECTIONALITY_CLASS 0x001FU
67
68
69 /*************************************************************************/
70 /*************************************************************************/
71 /***** *****/
72 /***** UTILITY FUNCTIONS *****/
73 /***** *****/
74 /*************************************************************************/
75 /*************************************************************************/
76
77 static void
78 gxv_prop_zero_advance_validate( FT_UShort gid,
79 GXV_Validator gxvalid )
80 {
81 FT_Face face;
82 FT_Error error;
83 FT_GlyphSlot glyph;
84
85
86 GXV_NAME_ENTER( "zero advance" );
87
88 face = gxvalid->face;
89
90 error = FT_Load_Glyph( face,
91 gid,
92 FT_LOAD_IGNORE_TRANSFORM );
93 if ( error )
94 FT_INVALID_GLYPH_ID;
95
96 glyph = face->glyph;
97
98 if ( glyph->advance.x != (FT_Pos)0 ||
99 glyph->advance.y != (FT_Pos)0 )
100 {
101 GXV_TRACE(( " found non-zero advance in zero-advance glyph\n" ));
102 FT_INVALID_DATA;
103 }
104
105 GXV_EXIT;
106 }
107
108
109 /* Pass 0 as GLYPH to check the default property */
110 static void
111 gxv_prop_property_validate( FT_UShort property,
112 FT_UShort glyph,
113 GXV_Validator gxvalid )
114 {
115 if ( glyph != 0 && ( property & GXV_PROP_FLOATER ) )
116 gxv_prop_zero_advance_validate( glyph, gxvalid );
117
118 if ( property & GXV_PROP_USE_COMPLEMENTARY_BRACKET )
119 {
120 FT_UShort offset;
121 char complement;
122
123
124 offset = (FT_UShort)( property & GXV_PROP_COMPLEMENTARY_BRACKET_OFFSET );
125 if ( offset == 0 )
126 {
127 GXV_TRACE(( " found zero offset to property\n" ));
128 FT_INVALID_OFFSET;
129 }
130
131 complement = (char)( offset >> 8 );
132 if ( complement & 0x08 )
133 {
134 /* Top bit is set: negative */
135
136 /* Calculate the absolute offset */
137 complement = (char)( ( complement & 0x07 ) + 1 );
138
139 /* The gid for complement must be greater than 0 */
140 if ( glyph <= complement )
141 {
142 GXV_TRACE(( " found non-positive glyph complement\n" ));
143 FT_INVALID_DATA;
144 }
145 }
146 else
147 {
148 /* The gid for complement must be the face. */
149 gxv_glyphid_validate( (FT_UShort)( glyph + complement ), gxvalid );
150 }
151 }
152 else
153 {
154 if ( property & GXV_PROP_COMPLEMENTARY_BRACKET_OFFSET )
155 GXV_TRACE(( "glyph %d cannot have complementary bracketing\n",
156 glyph ));
157 }
158
159 /* this is introduced in version 2.0 */
160 if ( property & GXV_PROP_ATTACHING_TO_RIGHT )
161 {
162 if ( GXV_PROP_DATA( version ) == 0x00010000UL )
163 {
164 GXV_TRACE(( " found older version (1.0) in new version table\n" ));
165 FT_INVALID_DATA;
166 }
167 }
168
169 if ( property & GXV_PROP_RESERVED )
170 {
171 GXV_TRACE(( " found non-zero bits in reserved bits\n" ));
172 FT_INVALID_DATA;
173 }
174
175 if ( ( property & GXV_PROP_DIRECTIONALITY_CLASS ) > 11 )
176 {
177 /* TODO: Too restricted. Use the validation level. */
178 if ( GXV_PROP_DATA( version ) == 0x00010000UL ||
179 GXV_PROP_DATA( version ) == 0x00020000UL )
180 {
181 GXV_TRACE(( " found too old version in directionality class\n" ));
182 FT_INVALID_DATA;
183 }
184 }
185 }
186
187
188 static void
189 gxv_prop_LookupValue_validate( FT_UShort glyph,
190 GXV_LookupValueCPtr value_p,
191 GXV_Validator gxvalid )
192 {
193 gxv_prop_property_validate( value_p->u, glyph, gxvalid );
194 }
195
196
197 /*
198 +===============+ --------+
199 | lookup header | |
200 +===============+ |
201 | BinSrchHeader | |
202 +===============+ |
203 | lastGlyph[0] | |
204 +---------------+ |
205 | firstGlyph[0] | | head of lookup table
206 +---------------+ | +
207 | offset[0] | -> | offset [byte]
208 +===============+ | +
209 | lastGlyph[1] | | (glyphID - firstGlyph) * 2 [byte]
210 +---------------+ |
211 | firstGlyph[1] | |
212 +---------------+ |
213 | offset[1] | |
214 +===============+ |
215 |
216 ... |
217 |
218 16bit value array |
219 +===============+ |
220 | value | <-------+
221 ...
222 */
223
224 static GXV_LookupValueDesc
225 gxv_prop_LookupFmt4_transit( FT_UShort relative_gindex,
226 GXV_LookupValueCPtr base_value_p,
227 FT_Bytes lookuptbl_limit,
228 GXV_Validator gxvalid )
229 {
230 FT_Bytes p;
231 FT_Bytes limit;
232 FT_UShort offset;
233 GXV_LookupValueDesc value;
234
235 /* XXX: check range? */
236 offset = (FT_UShort)( base_value_p->u +
237 relative_gindex * sizeof ( FT_UShort ) );
238 p = gxvalid->lookuptbl_head + offset;
239 limit = lookuptbl_limit;
240
241 GXV_LIMIT_CHECK ( 2 );
242 value.u = FT_NEXT_USHORT( p );
243
244 return value;
245 }
246
247
248 /*************************************************************************/
249 /*************************************************************************/
250 /***** *****/
251 /***** prop TABLE *****/
252 /***** *****/
253 /*************************************************************************/
254 /*************************************************************************/
255
256 FT_LOCAL_DEF( void )
257 gxv_prop_validate( FT_Bytes table,
258 FT_Face face,
259 FT_Validator ftvalid )
260 {
261 FT_Bytes p = table;
262 FT_Bytes limit = 0;
263 GXV_ValidatorRec gxvalidrec;
264 GXV_Validator gxvalid = &gxvalidrec;
265
266 GXV_prop_DataRec proprec;
267 GXV_prop_Data prop = &proprec;
268
269 FT_Fixed version;
270 FT_UShort format;
271 FT_UShort defaultProp;
272
273
274 gxvalid->root = ftvalid;
275 gxvalid->table_data = prop;
276 gxvalid->face = face;
277
278 FT_TRACE3(( "validating `prop' table\n" ));
279 GXV_INIT;
280
281 GXV_LIMIT_CHECK( 4 + 2 + 2 );
282 version = FT_NEXT_LONG( p );
283 format = FT_NEXT_USHORT( p );
284 defaultProp = FT_NEXT_USHORT( p );
285
286 GXV_TRACE(( " version 0x%08lx\n", version ));
287 GXV_TRACE(( " format 0x%04x\n", format ));
288 GXV_TRACE(( " defaultProp 0x%04x\n", defaultProp ));
289
290 /* only versions 1.0, 2.0, 3.0 are defined (1996) */
291 if ( version != 0x00010000UL &&
292 version != 0x00020000UL &&
293 version != 0x00030000UL )
294 {
295 GXV_TRACE(( " found unknown version\n" ));
296 FT_INVALID_FORMAT;
297 }
298
299
300 /* only formats 0x0000, 0x0001 are defined (1996) */
301 if ( format > 1 )
302 {
303 GXV_TRACE(( " found unknown format\n" ));
304 FT_INVALID_FORMAT;
305 }
306
307 gxv_prop_property_validate( defaultProp, 0, gxvalid );
308
309 if ( format == 0 )
310 {
311 FT_TRACE3(( "(format 0, no per-glyph properties, "
312 "remaining %ld bytes are skipped)", limit - p ));
313 goto Exit;
314 }
315
316 /* format == 1 */
317 GXV_PROP_DATA( version ) = version;
318
319 gxvalid->lookupval_sign = GXV_LOOKUPVALUE_UNSIGNED;
320 gxvalid->lookupval_func = gxv_prop_LookupValue_validate;
321 gxvalid->lookupfmt4_trans = gxv_prop_LookupFmt4_transit;
322
323 gxv_LookupTable_validate( p, limit, gxvalid );
324
325 Exit:
326 FT_TRACE4(( "\n" ));
327 }
328
329
330 /* END */