00001 /***************************************************************************/ 00002 /* */ 00003 /* ftvalid.h */ 00004 /* */ 00005 /* FreeType validation support (specification). */ 00006 /* */ 00007 /* Copyright 2004 by */ 00008 /* David Turner, Robert Wilhelm, and Werner Lemberg. */ 00009 /* */ 00010 /* This file is part of the FreeType project, and may only be used, */ 00011 /* modified, and distributed under the terms of the FreeType project */ 00012 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ 00013 /* this file you indicate that you have read the license and */ 00014 /* understand and accept it fully. */ 00015 /* */ 00016 /***************************************************************************/ 00017 00018 00019 #ifndef __FTVALID_H__ 00020 #define __FTVALID_H__ 00021 00022 #include <ft2build.h> 00023 #include FT_CONFIG_STANDARD_LIBRARY_H /* for ft_setjmp and ft_longjmp */ 00024 00025 00026 FT_BEGIN_HEADER 00027 00028 00029 /*************************************************************************/ 00030 /*************************************************************************/ 00031 /*************************************************************************/ 00032 /**** ****/ 00033 /**** ****/ 00034 /**** V A L I D A T I O N ****/ 00035 /**** ****/ 00036 /**** ****/ 00037 /*************************************************************************/ 00038 /*************************************************************************/ 00039 /*************************************************************************/ 00040 00041 /* handle to a validation object */ 00042 typedef struct FT_ValidatorRec_ volatile* FT_Validator; 00043 00044 00045 /*************************************************************************/ 00046 /* */ 00047 /* There are three distinct validation levels defined here: */ 00048 /* */ 00049 /* FT_VALIDATE_DEFAULT :: */ 00050 /* A table that passes this validation level can be used reliably by */ 00051 /* FreeType. It generally means that all offsets have been checked to */ 00052 /* prevent out-of-bound reads, that array counts are correct, etc. */ 00053 /* */ 00054 /* FT_VALIDATE_TIGHT :: */ 00055 /* A table that passes this validation level can be used reliably and */ 00056 /* doesn't contain invalid data. For example, a charmap table that */ 00057 /* returns invalid glyph indices will not pass, even though it can */ 00058 /* be used with FreeType in default mode (the library will simply */ 00059 /* return an error later when trying to load the glyph). */ 00060 /* */ 00061 /* It also checks that fields which must be a multiple of 2, 4, or 8, */ 00062 /* don't have incorrect values, etc. */ 00063 /* */ 00064 /* FT_VALIDATE_PARANOID :: */ 00065 /* Only for font debugging. Checks that a table follows the */ 00066 /* specification by 100%. Very few fonts will be able to pass this */ 00067 /* level anyway but it can be useful for certain tools like font */ 00068 /* editors/converters. */ 00069 /* */ 00070 typedef enum FT_ValidationLevel_ 00071 { 00072 FT_VALIDATE_DEFAULT = 0, 00073 FT_VALIDATE_TIGHT, 00074 FT_VALIDATE_PARANOID 00075 00076 } FT_ValidationLevel; 00077 00078 00079 /* validator structure */ 00080 typedef struct FT_ValidatorRec_ 00081 { 00082 const FT_Byte* base; /* address of table in memory */ 00083 const FT_Byte* limit; /* `base' + sizeof(table) in memory */ 00084 FT_ValidationLevel level; /* validation level */ 00085 FT_Error error; /* error returned. 0 means success */ 00086 00087 ft_jmp_buf jump_buffer; /* used for exception handling */ 00088 00089 } FT_ValidatorRec; 00090 00091 00092 #define FT_VALIDATOR( x ) ((FT_Validator)( x )) 00093 00094 00095 FT_BASE( void ) 00096 ft_validator_init( FT_Validator valid, 00097 const FT_Byte* base, 00098 const FT_Byte* limit, 00099 FT_ValidationLevel level ); 00100 00101 /* Do not use this. It's broken and will cause your validator to crash */ 00102 /* if you run it on an invalid font. */ 00103 FT_BASE( FT_Int ) 00104 ft_validator_run( FT_Validator valid ); 00105 00106 /* Sets the error field in a validator, then calls `longjmp' to return */ 00107 /* to high-level caller. Using `setjmp/longjmp' avoids many stupid */ 00108 /* error checks within the validation routines. */ 00109 /* */ 00110 FT_BASE( void ) 00111 ft_validator_error( FT_Validator valid, 00112 FT_Error error ); 00113 00114 00115 /* Calls ft_validate_error. Assumes that the `valid' local variable */ 00116 /* holds a pointer to the current validator object. */ 00117 /* */ 00118 /* Use preprocessor prescan to pass FT_ERR_PREFIX. */ 00119 /* */ 00120 #define FT_INVALID( _prefix, _error ) FT_INVALID_( _prefix, _error ) 00121 #define FT_INVALID_( _prefix, _error ) \ 00122 ft_validator_error( valid, _prefix ## _error ) 00123 00124 /* called when a broken table is detected */ 00125 #define FT_INVALID_TOO_SHORT \ 00126 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) 00127 00128 /* called when an invalid offset is detected */ 00129 #define FT_INVALID_OFFSET \ 00130 FT_INVALID( FT_ERR_PREFIX, Invalid_Offset ) 00131 00132 /* called when an invalid format/value is detected */ 00133 #define FT_INVALID_FORMAT \ 00134 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) 00135 00136 /* called when an invalid glyph index is detected */ 00137 #define FT_INVALID_GLYPH_ID \ 00138 FT_INVALID( FT_ERR_PREFIX, Invalid_Glyph_Index ) 00139 00140 /* called when an invalid field value is detected */ 00141 #define FT_INVALID_DATA \ 00142 FT_INVALID( FT_ERR_PREFIX, Invalid_Table ) 00143 00144 00145 FT_END_HEADER 00146 00147 #endif /* __FTVALID_H__ */ 00148 00149 00150 /* END */
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