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1 /***************************************************************************/ | |
2 /* */ | |
3 /* ftvalid.h */ | |
4 /* */ | |
5 /* FreeType validation support (specification). */ | |
6 /* */ | |
7 /* Copyright 2004, 2013 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, LICENSE.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 "../config/ftstdlib.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_ volatile* 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 #if defined( _MSC_VER ) /* Visual C++ (and Intel C++) */ | |
80 /* We disable the warning `structure was padded due to */ | |
81 /* __declspec(align())' in order to compile cleanly with */ | |
82 /* the maximum level of warnings. */ | |
83 #pragma warning( push ) | |
84 #pragma warning( disable : 4324 ) | |
85 #endif /* _MSC_VER */ | |
86 | |
87 /* validator structure */ | |
88 typedef struct FT_ValidatorRec_ | |
89 { | |
90 const FT_Byte* base; /* address of table in memory */ | |
91 const FT_Byte* limit; /* `base' + sizeof(table) in memory */ | |
92 FT_ValidationLevel level; /* validation level */ | |
93 FT_Error error; /* error returned. 0 means success */ | |
94 | |
95 ft_jmp_buf jump_buffer; /* used for exception handling */ | |
96 | |
97 } FT_ValidatorRec; | |
98 | |
99 #if defined( _MSC_VER ) | |
100 #pragma warning( pop ) | |
101 #endif | |
102 | |
103 #define FT_VALIDATOR( x ) ( (FT_Validator)( x ) ) | |
104 | |
105 | |
106 FT_BASE( void ) | |
107 ft_validator_init( FT_Validator valid, | |
108 const FT_Byte* base, | |
109 const FT_Byte* limit, | |
110 FT_ValidationLevel level ); | |
111 | |
112 /* Do not use this. It's broken and will cause your validator to crash */ | |
113 /* if you run it on an invalid font. */ | |
114 FT_BASE( FT_Int ) | |
115 ft_validator_run( FT_Validator valid ); | |
116 | |
117 /* Sets the error field in a validator, then calls `longjmp' to return */ | |
118 /* to high-level caller. Using `setjmp/longjmp' avoids many stupid */ | |
119 /* error checks within the validation routines. */ | |
120 /* */ | |
121 FT_BASE( void ) | |
122 ft_validator_error( FT_Validator valid, | |
123 FT_Error error ); | |
124 | |
125 | |
126 /* Calls ft_validate_error. Assumes that the `valid' local variable */ | |
127 /* holds a pointer to the current validator object. */ | |
128 /* */ | |
129 /* Use preprocessor prescan to pass FT_ERR_PREFIX. */ | |
130 /* */ | |
131 #define FT_INVALID( _prefix, _error ) FT_INVALID_( _prefix, _error ) | |
132 #define FT_INVALID_( _prefix, _error ) \ | |
133 ft_validator_error( valid, _prefix ## _error ) | |
134 | |
135 /* called when a broken table is detected */ | |
136 #define FT_INVALID_TOO_SHORT \ | |
137 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) | |
138 | |
139 /* called when an invalid offset is detected */ | |
140 #define FT_INVALID_OFFSET \ | |
141 FT_INVALID( FT_ERR_PREFIX, Invalid_Offset ) | |
142 | |
143 /* called when an invalid format/value is detected */ | |
144 #define FT_INVALID_FORMAT \ | |
145 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) | |
146 | |
147 /* called when an invalid glyph index is detected */ | |
148 #define FT_INVALID_GLYPH_ID \ | |
149 FT_INVALID( FT_ERR_PREFIX, Invalid_Glyph_Index ) | |
150 | |
151 /* called when an invalid field value is detected */ | |
152 #define FT_INVALID_DATA \ | |
153 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) | |
154 | |
155 | |
156 FT_END_HEADER | |
157 | |
158 #endif /* __FTVALID_H__ */ | |
159 | |
160 | |
161 /* END */ | |
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