1 /****************************************************************************
2 *
3 * gxvopbd.c
4 *
5 * TrueTypeGX/AAT opbd 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 gxvopbd
40
41
42 /*************************************************************************/
43 /*************************************************************************/
44 /***** *****/
45 /***** Data and Types *****/
46 /***** *****/
47 /*************************************************************************/
48 /*************************************************************************/
49
50 typedef struct GXV_opbd_DataRec_
51 {
52 FT_UShort format;
53 FT_UShort valueOffset_min;
54
55 } GXV_opbd_DataRec, *GXV_opbd_Data;
56
57
58 #define GXV_OPBD_DATA( FIELD ) GXV_TABLE_DATA( opbd, FIELD )
59
60
61 /*************************************************************************/
62 /*************************************************************************/
63 /***** *****/
64 /***** UTILITY FUNCTIONS *****/
65 /***** *****/
66 /*************************************************************************/
67 /*************************************************************************/
68
69 static void
70 gxv_opbd_LookupValue_validate( FT_UShort glyph,
71 GXV_LookupValueCPtr value_p,
72 GXV_Validator gxvalid )
73 {
74 /* offset in LookupTable is measured from the head of opbd table */
75 FT_Bytes p = gxvalid->root->base + value_p->u;
76 FT_Bytes limit = gxvalid->root->limit;
77 FT_Short delta_value;
78 int i;
79
80
81 if ( value_p->u < GXV_OPBD_DATA( valueOffset_min ) )
82 GXV_OPBD_DATA( valueOffset_min ) = value_p->u;
83
84 for ( i = 0; i < 4; i++ )
85 {
86 GXV_LIMIT_CHECK( 2 );
87 delta_value = FT_NEXT_SHORT( p );
88
89 if ( GXV_OPBD_DATA( format ) ) /* format 1, value is ctrl pt. */
90 {
91 if ( delta_value == -1 )
92 continue;
93
94 gxv_ctlPoint_validate( glyph, (FT_UShort)delta_value, gxvalid );
95 }
96 else /* format 0, value is distance */
97 continue;
98 }
99 }
100
101
102 /*
103 opbd ---------------------+
104 |
105 +===============+ |
106 | lookup header | |
107 +===============+ |
108 | BinSrchHeader | |
109 +===============+ |
110 | lastGlyph[0] | |
111 +---------------+ |
112 | firstGlyph[0] | | head of opbd sfnt table
113 +---------------+ | +
114 | offset[0] | -> | offset [byte]
115 +===============+ | +
116 | lastGlyph[1] | | (glyphID - firstGlyph) * 4 * sizeof(FT_Short) [byte]
117 +---------------+ |
118 | firstGlyph[1] | |
119 +---------------+ |
120 | offset[1] | |
121 +===============+ |
122 |
123 .... |
124 |
125 48bit value array |
126 +===============+ |
127 | value | <-------+
128 | |
129 | |
130 | |
131 +---------------+
132 .... */
133
134 static GXV_LookupValueDesc
135 gxv_opbd_LookupFmt4_transit( FT_UShort relative_gindex,
136 GXV_LookupValueCPtr base_value_p,
137 FT_Bytes lookuptbl_limit,
138 GXV_Validator gxvalid )
139 {
140 GXV_LookupValueDesc value;
141
142 FT_UNUSED( lookuptbl_limit );
143 FT_UNUSED( gxvalid );
144
145 /* XXX: check range? */
146 value.u = (FT_UShort)( base_value_p->u +
147 relative_gindex * 4 * sizeof ( FT_Short ) );
148
149 return value;
150 }
151
152
153 /*************************************************************************/
154 /*************************************************************************/
155 /***** *****/
156 /***** opbd TABLE *****/
157 /***** *****/
158 /*************************************************************************/
159 /*************************************************************************/
160
161 FT_LOCAL_DEF( void )
162 gxv_opbd_validate( FT_Bytes table,
163 FT_Face face,
164 FT_Validator ftvalid )
165 {
166 GXV_ValidatorRec gxvalidrec;
167 GXV_Validator gxvalid = &gxvalidrec;
168 GXV_opbd_DataRec opbdrec;
169 GXV_opbd_Data opbd = &opbdrec;
170 FT_Bytes p = table;
171 FT_Bytes limit = 0;
172
173 FT_ULong version;
174
175
176 gxvalid->root = ftvalid;
177 gxvalid->table_data = opbd;
178 gxvalid->face = face;
179
180 FT_TRACE3(( "validating `opbd' table\n" ));
181 GXV_INIT;
182 GXV_OPBD_DATA( valueOffset_min ) = 0xFFFFU;
183
184
185 GXV_LIMIT_CHECK( 4 + 2 );
186 version = FT_NEXT_ULONG( p );
187 GXV_OPBD_DATA( format ) = FT_NEXT_USHORT( p );
188
189
190 /* only 0x00010000 is defined (1996) */
191 GXV_TRACE(( "(version=0x%08lx)\n", version ));
192 if ( 0x00010000UL != version )
193 FT_INVALID_FORMAT;
194
195 /* only values 0 and 1 are defined (1996) */
196 GXV_TRACE(( "(format=0x%04x)\n", GXV_OPBD_DATA( format ) ));
197 if ( 0x0001 < GXV_OPBD_DATA( format ) )
198 FT_INVALID_FORMAT;
199
200 gxvalid->lookupval_sign = GXV_LOOKUPVALUE_UNSIGNED;
201 gxvalid->lookupval_func = gxv_opbd_LookupValue_validate;
202 gxvalid->lookupfmt4_trans = gxv_opbd_LookupFmt4_transit;
203
204 gxv_LookupTable_validate( p, limit, gxvalid );
205 p += gxvalid->subtable_length;
206
207 if ( p > table + GXV_OPBD_DATA( valueOffset_min ) )
208 {
209 GXV_TRACE((
210 "found overlap between LookupTable and opbd_value array\n" ));
211 FT_INVALID_OFFSET;
212 }
213
214 FT_TRACE4(( "\n" ));
215 }
216
217
218 /* END */