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, 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 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 /* 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 /* Do not use this. It's broken and will cause your validator to crash */ 102 /* if you run it on an invalid font. */ 103 FT_BASE( FT_Int ) 104 ft_validator_run( FT_Validator valid ); 105 106 /* Sets the error field in a validator, then calls `longjmp' to return */ 107 /* to high-level caller. Using `setjmp/longjmp' avoids many stupid */ 108 /* error checks within the validation routines. */ 109 /* */ 110 FT_BASE( void ) 111 ft_validator_error( FT_Validator valid, 112 FT_Error error ); 113 114 115 /* Calls ft_validate_error. Assumes that the `valid' local variable */ 116 /* holds a pointer to the current validator object. */ 117 /* */ 118 /* Use preprocessor prescan to pass FT_ERR_PREFIX. */ 119 /* */ 120 #define FT_INVALID( _prefix, _error ) FT_INVALID_( _prefix, _error ) 121 #define FT_INVALID_( _prefix, _error ) \ 122 ft_validator_error( valid, _prefix ## _error ) 123 124 /* called when a broken table is detected */ 125 #define FT_INVALID_TOO_SHORT \ 126 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) 127 128 /* called when an invalid offset is detected */ 129 #define FT_INVALID_OFFSET \ 130 FT_INVALID( FT_ERR_PREFIX, Invalid_Offset ) 131 132 /* called when an invalid format/value is detected */ 133 #define FT_INVALID_FORMAT \ 134 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) 135 136 /* called when an invalid glyph index is detected */ 137 #define FT_INVALID_GLYPH_ID \ 138 FT_INVALID( FT_ERR_PREFIX, Invalid_Glyph_Index ) 139 140 /* called when an invalid field value is detected */ 141 #define FT_INVALID_DATA \ 142 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) 143 144 145 FT_END_HEADER 146 147 #endif /* __FTVALID_H__ */ 148 149 150 /* END */ 151
