|
1 /***************************************************************************/ |
|
2 /* */ |
|
3 /* ftvalid.h */ |
|
4 /* */ |
|
5 /* FreeType validation support (specification). */ |
|
6 /* */ |
|
7 /* Copyright 2004 by */ |
|
8 /* David Turner, Robert Wilhelm, and Werner Lemberg. */ |
|
9 /* */ |
|
10 /* This file is part of the FreeType project, and may only be used, */ |
|
11 /* modified, and distributed under the terms of the FreeType project */ |
|
12 /* license, FTL.TXT. By continuing to use, modify, or distribute */ |
|
13 /* this file you indicate that you have read the license and */ |
|
14 /* understand and accept it fully. */ |
|
15 /* */ |
|
16 /***************************************************************************/ |
|
17 |
|
18 |
|
19 #ifndef __FTVALID_H__ |
|
20 #define __FTVALID_H__ |
|
21 |
|
22 #include <ft2build.h> |
|
23 #include FT_CONFIG_STANDARD_LIBRARY_H /* for ft_setjmp and ft_longjmp */ |
|
24 |
|
25 |
|
26 FT_BEGIN_HEADER |
|
27 |
|
28 |
|
29 /*************************************************************************/ |
|
30 /*************************************************************************/ |
|
31 /*************************************************************************/ |
|
32 /**** ****/ |
|
33 /**** ****/ |
|
34 /**** V A L I D A T I O N ****/ |
|
35 /**** ****/ |
|
36 /**** ****/ |
|
37 /*************************************************************************/ |
|
38 /*************************************************************************/ |
|
39 /*************************************************************************/ |
|
40 |
|
41 /* handle to a validation object */ |
|
42 typedef struct FT_ValidatorRec_* FT_Validator; |
|
43 |
|
44 |
|
45 /*************************************************************************/ |
|
46 /* */ |
|
47 /* There are three distinct validation levels defined here: */ |
|
48 /* */ |
|
49 /* FT_VALIDATE_DEFAULT :: */ |
|
50 /* A table that passes this validation level can be used reliably by */ |
|
51 /* FreeType. It generally means that all offsets have been checked to */ |
|
52 /* prevent out-of-bound reads, that array counts are correct, etc. */ |
|
53 /* */ |
|
54 /* FT_VALIDATE_TIGHT :: */ |
|
55 /* A table that passes this validation level can be used reliably and */ |
|
56 /* doesn't contain invalid data. For example, a charmap table that */ |
|
57 /* returns invalid glyph indices will not pass, even though it can */ |
|
58 /* be used with FreeType in default mode (the library will simply */ |
|
59 /* return an error later when trying to load the glyph). */ |
|
60 /* */ |
|
61 /* It also checks that fields which must be a multiple of 2, 4, or 8, */ |
|
62 /* don't have incorrect values, etc. */ |
|
63 /* */ |
|
64 /* FT_VALIDATE_PARANOID :: */ |
|
65 /* Only for font debugging. Checks that a table follows the */ |
|
66 /* specification by 100%. Very few fonts will be able to pass this */ |
|
67 /* level anyway but it can be useful for certain tools like font */ |
|
68 /* editors/converters. */ |
|
69 /* */ |
|
70 typedef enum FT_ValidationLevel_ |
|
71 { |
|
72 FT_VALIDATE_DEFAULT = 0, |
|
73 FT_VALIDATE_TIGHT, |
|
74 FT_VALIDATE_PARANOID |
|
75 |
|
76 } FT_ValidationLevel; |
|
77 |
|
78 |
|
79 /* validator structure */ |
|
80 typedef struct FT_ValidatorRec_ |
|
81 { |
|
82 const FT_Byte* base; /* address of table in memory */ |
|
83 const FT_Byte* limit; /* `base' + sizeof(table) in memory */ |
|
84 FT_ValidationLevel level; /* validation level */ |
|
85 FT_Error error; /* error returned. 0 means success */ |
|
86 |
|
87 ft_jmp_buf jump_buffer; /* used for exception handling */ |
|
88 |
|
89 } FT_ValidatorRec; |
|
90 |
|
91 |
|
92 #define FT_VALIDATOR( x ) ((FT_Validator)( x )) |
|
93 |
|
94 |
|
95 FT_BASE( void ) |
|
96 ft_validator_init( FT_Validator valid, |
|
97 const FT_Byte* base, |
|
98 const FT_Byte* limit, |
|
99 FT_ValidationLevel level ); |
|
100 |
|
101 FT_BASE( FT_Int ) |
|
102 ft_validator_run( FT_Validator valid ); |
|
103 |
|
104 /* Sets the error field in a validator, then calls `longjmp' to return */ |
|
105 /* to high-level caller. Using `setjmp/longjmp' avoids many stupid */ |
|
106 /* error checks within the validation routines. */ |
|
107 /* */ |
|
108 FT_BASE( void ) |
|
109 ft_validator_error( FT_Validator valid, |
|
110 FT_Error error ); |
|
111 |
|
112 |
|
113 /* Calls ft_validate_error. Assumes that the `valid' local variable */ |
|
114 /* holds a pointer to the current validator object. */ |
|
115 /* */ |
|
116 /* Use preprocessor prescan to pass FT_ERR_PREFIX. */ |
|
117 /* */ |
|
118 #define FT_INVALID( _prefix, _error ) FT_INVALID_( _prefix, _error ) |
|
119 #define FT_INVALID_( _prefix, _error ) \ |
|
120 ft_validator_error( valid, _prefix ## _error ) |
|
121 |
|
122 /* called when a broken table is detected */ |
|
123 #define FT_INVALID_TOO_SHORT \ |
|
124 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) |
|
125 |
|
126 /* called when an invalid offset is detected */ |
|
127 #define FT_INVALID_OFFSET \ |
|
128 FT_INVALID( FT_ERR_PREFIX, Invalid_Offset ) |
|
129 |
|
130 /* called when an invalid format/value is detected */ |
|
131 #define FT_INVALID_FORMAT \ |
|
132 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) |
|
133 |
|
134 /* called when an invalid glyph index is detected */ |
|
135 #define FT_INVALID_GLYPH_ID \ |
|
136 FT_INVALID( FT_ERR_PREFIX, Invalid_Glyph_Index ) |
|
137 |
|
138 /* called when an invalid field value is detected */ |
|
139 #define FT_INVALID_DATA \ |
|
140 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) |
|
141 |
|
142 |
|
143 FT_END_HEADER |
|
144 |
|
145 #endif /* __FTVALID_H__ */ |
|
146 |
|
147 |
|
148 /* END */ |