1/****************************************************************************
2 *
3 * ftvalid.h
4 *
5 * FreeType validation support (specification).
6 *
7 * Copyright (C) 2004-2019 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 FT_CONFIG_STANDARD_LIBRARY_H /* for ft_setjmp and ft_longjmp */
24
25
26FT_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 be
58 * used with FreeType in default mode (the library will simply return an
59 * 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 level
67 * 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 ft_jmp_buf jump_buffer; /* used for exception handling */
91
92 const FT_Byte* base; /* address of table in memory */
93 const FT_Byte* limit; /* `base' + sizeof(table) in memory */
94 FT_ValidationLevel level; /* validation level */
95 FT_Error error; /* error returned. 0 means success */
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#define FT_INVALID( _error ) FT_INVALID_( _error )
130#define FT_INVALID_( _error ) \
131 ft_validator_error( valid, FT_THROW( _error ) )
132
133 /* called when a broken table is detected */
134#define FT_INVALID_TOO_SHORT \
135 FT_INVALID( Invalid_Table )
136
137 /* called when an invalid offset is detected */
138#define FT_INVALID_OFFSET \
139 FT_INVALID( Invalid_Offset )
140
141 /* called when an invalid format/value is detected */
142#define FT_INVALID_FORMAT \
143 FT_INVALID( Invalid_Table )
144
145 /* called when an invalid glyph index is detected */
146#define FT_INVALID_GLYPH_ID \
147 FT_INVALID( Invalid_Glyph_Index )
148
149 /* called when an invalid field value is detected */
150#define FT_INVALID_DATA \
151 FT_INVALID( Invalid_Table )
152
153
154FT_END_HEADER
155
156#endif /* FTVALID_H_ */
157
158
159/* END */
160