reactos/lib/freetype/include/freetype/internal/ftvalid.h

   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_*  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   FT_BASE( FT_Int )
 102   ft_validator_run( FT_Validator  valid );
 103
 104   /* Sets the error field in a validator, then calls `longjmp' to return */
 105   /* to high-level caller.  Using `setjmp/longjmp' avoids many stupid    */
 106   /* error checks within the validation routines.                        */
 107   /*                                                                     */
 108   FT_BASE( void )
 109   ft_validator_error( FT_Validator  valid,
 110                       FT_Error      error );
 111
 112
 113   /* Calls ft_validate_error.  Assumes that the `valid' local variable */
 114   /* holds a pointer to the current validator object.                  */
 115   /*                                                                   */
 116   /* Use preprocessor prescan to pass FT_ERR_PREFIX.                   */
 117   /*                                                                   */
 118 #define FT_INVALID( _prefix, _error )  FT_INVALID_( _prefix, _error )
 119 #define FT_INVALID_( _prefix, _error ) \
 120           ft_validator_error( valid, _prefix ## _error )
 121
 122   /* called when a broken table is detected */
 123 #define FT_INVALID_TOO_SHORT \
 124           FT_INVALID( FT_ERR_PREFIX, Invalid_Table )
 125
 126   /* called when an invalid offset is detected */
 127 #define FT_INVALID_OFFSET \
 128           FT_INVALID( FT_ERR_PREFIX, Invalid_Offset )
 129
 130   /* called when an invalid format/value is detected */
 131 #define FT_INVALID_FORMAT \
 132           FT_INVALID( FT_ERR_PREFIX, Invalid_Table )
 133
 134   /* called when an invalid glyph index is detected */
 135 #define FT_INVALID_GLYPH_ID \
 136           FT_INVALID( FT_ERR_PREFIX, Invalid_Glyph_Index )
 137
 138   /* called when an invalid field value is detected */
 139 #define FT_INVALID_DATA \
 140           FT_INVALID( FT_ERR_PREFIX, Invalid_Table )
 141
 142
 143 FT_END_HEADER
 144
 145 #endif /* __FTVALID_H__ */
 146
 147
 148 /* END */