160 lines
5.6 KiB
C
160 lines
5.6 KiB
C
/****************************************************************************
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*
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* ftvalid.h
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*
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* FreeType validation support (specification).
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*
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* Copyright (C) 2004-2020 by
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* David Turner, Robert Wilhelm, and Werner Lemberg.
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*
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* This file is part of the FreeType project, and may only be used,
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* modified, and distributed under the terms of the FreeType project
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* license, LICENSE.TXT. By continuing to use, modify, or distribute
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* this file you indicate that you have read the license and
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* understand and accept it fully.
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*
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*/
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#ifndef FTVALID_H_
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#define FTVALID_H_
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#include <ft2build.h>
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#include FT_CONFIG_STANDARD_LIBRARY_H /* for ft_setjmp and ft_longjmp */
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FT_BEGIN_HEADER
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/**** ****/
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/**** ****/
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/**** V A L I D A T I O N ****/
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/**** ****/
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/**** ****/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/* handle to a validation object */
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typedef struct FT_ValidatorRec_ volatile* FT_Validator;
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/**************************************************************************
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*
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* There are three distinct validation levels defined here:
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*
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* FT_VALIDATE_DEFAULT ::
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* A table that passes this validation level can be used reliably by
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* FreeType. It generally means that all offsets have been checked to
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* prevent out-of-bound reads, that array counts are correct, etc.
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*
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* FT_VALIDATE_TIGHT ::
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* A table that passes this validation level can be used reliably and
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* doesn't contain invalid data. For example, a charmap table that
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* returns invalid glyph indices will not pass, even though it can be
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* used with FreeType in default mode (the library will simply return an
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* error later when trying to load the glyph).
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*
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* It also checks that fields which must be a multiple of 2, 4, or 8,
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* don't have incorrect values, etc.
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*
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* FT_VALIDATE_PARANOID ::
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* Only for font debugging. Checks that a table follows the
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* specification by 100%. Very few fonts will be able to pass this level
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* anyway but it can be useful for certain tools like font
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* editors/converters.
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*/
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typedef enum FT_ValidationLevel_
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{
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FT_VALIDATE_DEFAULT = 0,
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FT_VALIDATE_TIGHT,
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FT_VALIDATE_PARANOID
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} FT_ValidationLevel;
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#if defined( _MSC_VER ) /* Visual C++ (and Intel C++) */
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/* We disable the warning `structure was padded due to */
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/* __declspec(align())' in order to compile cleanly with */
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/* the maximum level of warnings. */
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#pragma warning( push )
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#pragma warning( disable : 4324 )
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#endif /* _MSC_VER */
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/* validator structure */
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typedef struct FT_ValidatorRec_
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{
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ft_jmp_buf jump_buffer; /* used for exception handling */
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const FT_Byte* base; /* address of table in memory */
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const FT_Byte* limit; /* `base' + sizeof(table) in memory */
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FT_ValidationLevel level; /* validation level */
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FT_Error error; /* error returned. 0 means success */
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} FT_ValidatorRec;
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#if defined( _MSC_VER )
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#pragma warning( pop )
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#endif
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#define FT_VALIDATOR( x ) ( (FT_Validator)( x ) )
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FT_BASE( void )
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ft_validator_init( FT_Validator valid,
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const FT_Byte* base,
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const FT_Byte* limit,
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FT_ValidationLevel level );
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/* Do not use this. It's broken and will cause your validator to crash */
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/* if you run it on an invalid font. */
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FT_BASE( FT_Int )
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ft_validator_run( FT_Validator valid );
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/* Sets the error field in a validator, then calls `longjmp' to return */
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/* to high-level caller. Using `setjmp/longjmp' avoids many stupid */
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/* error checks within the validation routines. */
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/* */
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FT_BASE( void )
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ft_validator_error( FT_Validator valid,
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FT_Error error );
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/* Calls ft_validate_error. Assumes that the `valid' local variable */
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/* holds a pointer to the current validator object. */
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/* */
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#define FT_INVALID( _error ) FT_INVALID_( _error )
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#define FT_INVALID_( _error ) \
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ft_validator_error( valid, FT_THROW( _error ) )
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/* called when a broken table is detected */
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#define FT_INVALID_TOO_SHORT \
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FT_INVALID( Invalid_Table )
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/* called when an invalid offset is detected */
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#define FT_INVALID_OFFSET \
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FT_INVALID( Invalid_Offset )
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/* called when an invalid format/value is detected */
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#define FT_INVALID_FORMAT \
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FT_INVALID( Invalid_Table )
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/* called when an invalid glyph index is detected */
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#define FT_INVALID_GLYPH_ID \
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FT_INVALID( Invalid_Glyph_Index )
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/* called when an invalid field value is detected */
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#define FT_INVALID_DATA \
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FT_INVALID( Invalid_Table )
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FT_END_HEADER
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#endif /* FTVALID_H_ */
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/* END */
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