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4680 | right-hear | 1 | /***************************************************************************/ |
2 | /* */ |
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3 | /* ftvalid.h */ |
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4 | /* */ |
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5 | /* FreeType validation support (specification). */ |
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6 | /* */ |
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7 | /* Copyright 2004 by */ |
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8 | /* David Turner, Robert Wilhelm, and Werner Lemberg. */ |
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9 | /* */ |
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10 | /* This file is part of the FreeType project, and may only be used, */ |
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11 | /* modified, and distributed under the terms of the FreeType project */ |
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12 | /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ |
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13 | /* this file you indicate that you have read the license and */ |
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14 | /* understand and accept it fully. */ |
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15 | /* */ |
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16 | /***************************************************************************/ |
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17 | |||
18 | |||
19 | #ifndef __FTVALID_H__ |
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20 | #define __FTVALID_H__ |
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21 | |||
22 | #include |
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23 | #include FT_CONFIG_STANDARD_LIBRARY_H /* for ft_setjmp and ft_longjmp */ |
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24 | |||
25 | |||
26 | FT_BEGIN_HEADER |
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27 | |||
28 | |||
29 | /*************************************************************************/ |
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30 | /*************************************************************************/ |
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31 | /*************************************************************************/ |
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32 | /**** ****/ |
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33 | /**** ****/ |
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34 | /**** V A L I D A T I O N ****/ |
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35 | /**** ****/ |
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36 | /**** ****/ |
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37 | /*************************************************************************/ |
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38 | /*************************************************************************/ |
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39 | /*************************************************************************/ |
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40 | |||
41 | /* handle to a validation object */ |
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42 | typedef struct FT_ValidatorRec_ volatile* FT_Validator; |
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43 | |||
44 | |||
45 | /*************************************************************************/ |
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46 | /* */ |
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47 | /* There are three distinct validation levels defined here: */ |
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48 | /* */ |
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49 | /* FT_VALIDATE_DEFAULT :: */ |
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50 | /* A table that passes this validation level can be used reliably by */ |
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51 | /* FreeType. It generally means that all offsets have been checked to */ |
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52 | /* prevent out-of-bound reads, that array counts are correct, etc. */ |
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53 | /* */ |
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54 | /* FT_VALIDATE_TIGHT :: */ |
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55 | /* A table that passes this validation level can be used reliably and */ |
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56 | /* doesn't contain invalid data. For example, a charmap table that */ |
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57 | /* returns invalid glyph indices will not pass, even though it can */ |
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58 | /* be used with FreeType in default mode (the library will simply */ |
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59 | /* return an error later when trying to load the glyph). */ |
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60 | /* */ |
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61 | /* It also checks that fields which must be a multiple of 2, 4, or 8, */ |
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62 | /* don't have incorrect values, etc. */ |
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63 | /* */ |
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64 | /* FT_VALIDATE_PARANOID :: */ |
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65 | /* Only for font debugging. Checks that a table follows the */ |
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66 | /* specification by 100%. Very few fonts will be able to pass this */ |
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67 | /* level anyway but it can be useful for certain tools like font */ |
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68 | /* editors/converters. */ |
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69 | /* */ |
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70 | typedef enum FT_ValidationLevel_ |
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71 | { |
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72 | FT_VALIDATE_DEFAULT = 0, |
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73 | FT_VALIDATE_TIGHT, |
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74 | FT_VALIDATE_PARANOID |
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75 | |||
76 | } FT_ValidationLevel; |
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77 | |||
78 | |||
79 | /* validator structure */ |
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80 | typedef struct FT_ValidatorRec_ |
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81 | { |
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82 | const FT_Byte* base; /* address of table in memory */ |
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83 | const FT_Byte* limit; /* `base' + sizeof(table) in memory */ |
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84 | FT_ValidationLevel level; /* validation level */ |
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85 | FT_Error error; /* error returned. 0 means success */ |
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86 | |||
87 | ft_jmp_buf jump_buffer; /* used for exception handling */ |
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88 | |||
89 | } FT_ValidatorRec; |
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90 | |||
91 | |||
92 | #define FT_VALIDATOR( x ) ((FT_Validator)( x )) |
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93 | |||
94 | |||
95 | FT_BASE( void ) |
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96 | ft_validator_init( FT_Validator valid, |
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97 | const FT_Byte* base, |
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98 | const FT_Byte* limit, |
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99 | FT_ValidationLevel level ); |
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100 | |||
101 | /* Do not use this. It's broken and will cause your validator to crash */ |
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102 | /* if you run it on an invalid font. */ |
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103 | FT_BASE( FT_Int ) |
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104 | ft_validator_run( FT_Validator valid ); |
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105 | |||
106 | /* Sets the error field in a validator, then calls `longjmp' to return */ |
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107 | /* to high-level caller. Using `setjmp/longjmp' avoids many stupid */ |
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108 | /* error checks within the validation routines. */ |
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109 | /* */ |
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110 | FT_BASE( void ) |
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111 | ft_validator_error( FT_Validator valid, |
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112 | FT_Error error ); |
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113 | |||
114 | |||
115 | /* Calls ft_validate_error. Assumes that the `valid' local variable */ |
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116 | /* holds a pointer to the current validator object. */ |
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117 | /* */ |
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118 | /* Use preprocessor prescan to pass FT_ERR_PREFIX. */ |
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119 | /* */ |
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120 | #define FT_INVALID( _prefix, _error ) FT_INVALID_( _prefix, _error ) |
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121 | #define FT_INVALID_( _prefix, _error ) \ |
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122 | ft_validator_error( valid, _prefix ## _error ) |
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123 | |||
124 | /* called when a broken table is detected */ |
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125 | #define FT_INVALID_TOO_SHORT \ |
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126 | FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) |
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127 | |||
128 | /* called when an invalid offset is detected */ |
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129 | #define FT_INVALID_OFFSET \ |
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130 | FT_INVALID( FT_ERR_PREFIX, Invalid_Offset ) |
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131 | |||
132 | /* called when an invalid format/value is detected */ |
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133 | #define FT_INVALID_FORMAT \ |
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134 | FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) |
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135 | |||
136 | /* called when an invalid glyph index is detected */ |
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137 | #define FT_INVALID_GLYPH_ID \ |
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138 | FT_INVALID( FT_ERR_PREFIX, Invalid_Glyph_Index ) |
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139 | |||
140 | /* called when an invalid field value is detected */ |
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141 | #define FT_INVALID_DATA \ |
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142 | FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) |
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143 | |||
144 | |||
145 | FT_END_HEADER |
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146 | |||
147 | #endif /* __FTVALID_H__ */ |
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148 | |||
149 | |||
150 | /* END */ |