ftvalid.h
上传用户:yisoukefu
上传日期:2020-08-09
资源大小:39506k
文件大小:7k
- /***************************************************************************/
- /* */
- /* ftvalid.h */
- /* */
- /* FreeType validation support (specification). */
- /* */
- /* Copyright 2004 by */
- /* David Turner, Robert Wilhelm, and Werner Lemberg. */
- /* */
- /* This file is part of the FreeType project, and may only be used, */
- /* modified, and distributed under the terms of the FreeType project */
- /* license, LICENSE.TXT. By continuing to use, modify, or distribute */
- /* this file you indicate that you have read the license and */
- /* understand and accept it fully. */
- /* */
- /***************************************************************************/
- #ifndef __FTVALID_H__
- #define __FTVALID_H__
- #include <ft2build.h>
- #include FT_CONFIG_STANDARD_LIBRARY_H /* for ft_setjmp and ft_longjmp */
- FT_BEGIN_HEADER
- /*************************************************************************/
- /*************************************************************************/
- /*************************************************************************/
- /**** ****/
- /**** ****/
- /**** V A L I D A T I O N ****/
- /**** ****/
- /**** ****/
- /*************************************************************************/
- /*************************************************************************/
- /*************************************************************************/
- /* handle to a validation object */
- typedef struct FT_ValidatorRec_ volatile* FT_Validator;
- /*************************************************************************/
- /* */
- /* There are three distinct validation levels defined here: */
- /* */
- /* FT_VALIDATE_DEFAULT :: */
- /* A table that passes this validation level can be used reliably by */
- /* FreeType. It generally means that all offsets have been checked to */
- /* prevent out-of-bound reads, that array counts are correct, etc. */
- /* */
- /* FT_VALIDATE_TIGHT :: */
- /* A table that passes this validation level can be used reliably and */
- /* doesn't contain invalid data. For example, a charmap table that */
- /* returns invalid glyph indices will not pass, even though it can */
- /* be used with FreeType in default mode (the library will simply */
- /* return an error later when trying to load the glyph). */
- /* */
- /* It also checks that fields which must be a multiple of 2, 4, or 8, */
- /* don't have incorrect values, etc. */
- /* */
- /* FT_VALIDATE_PARANOID :: */
- /* Only for font debugging. Checks that a table follows the */
- /* specification by 100%. Very few fonts will be able to pass this */
- /* level anyway but it can be useful for certain tools like font */
- /* editors/converters. */
- /* */
- typedef enum FT_ValidationLevel_
- {
- FT_VALIDATE_DEFAULT = 0,
- FT_VALIDATE_TIGHT,
- FT_VALIDATE_PARANOID
- } FT_ValidationLevel;
- /* validator structure */
- typedef struct FT_ValidatorRec_
- {
- const FT_Byte* base; /* address of table in memory */
- const FT_Byte* limit; /* `base' + sizeof(table) in memory */
- FT_ValidationLevel level; /* validation level */
- FT_Error error; /* error returned. 0 means success */
- ft_jmp_buf jump_buffer; /* used for exception handling */
- } FT_ValidatorRec;
- #define FT_VALIDATOR( x ) ((FT_Validator)( x ))
- FT_BASE( void )
- ft_validator_init( FT_Validator valid,
- const FT_Byte* base,
- const FT_Byte* limit,
- FT_ValidationLevel level );
- /* Do not use this. It's broken and will cause your validator to crash */
- /* if you run it on an invalid font. */
- FT_BASE( FT_Int )
- ft_validator_run( FT_Validator valid );
- /* Sets the error field in a validator, then calls `longjmp' to return */
- /* to high-level caller. Using `setjmp/longjmp' avoids many stupid */
- /* error checks within the validation routines. */
- /* */
- FT_BASE( void )
- ft_validator_error( FT_Validator valid,
- FT_Error error );
- /* Calls ft_validate_error. Assumes that the `valid' local variable */
- /* holds a pointer to the current validator object. */
- /* */
- /* Use preprocessor prescan to pass FT_ERR_PREFIX. */
- /* */
- #define FT_INVALID( _prefix, _error ) FT_INVALID_( _prefix, _error )
- #define FT_INVALID_( _prefix, _error )
- ft_validator_error( valid, _prefix ## _error )
- /* called when a broken table is detected */
- #define FT_INVALID_TOO_SHORT
- FT_INVALID( FT_ERR_PREFIX, Invalid_Table )
- /* called when an invalid offset is detected */
- #define FT_INVALID_OFFSET
- FT_INVALID( FT_ERR_PREFIX, Invalid_Offset )
- /* called when an invalid format/value is detected */
- #define FT_INVALID_FORMAT
- FT_INVALID( FT_ERR_PREFIX, Invalid_Table )
- /* called when an invalid glyph index is detected */
- #define FT_INVALID_GLYPH_ID
- FT_INVALID( FT_ERR_PREFIX, Invalid_Glyph_Index )
- /* called when an invalid field value is detected */
- #define FT_INVALID_DATA
- FT_INVALID( FT_ERR_PREFIX, Invalid_Table )
- FT_END_HEADER
- #endif /* __FTVALID_H__ */
- /* END */