Werner Lemberg
21 years ago
parent
1357c19b65
commit
645af08157
11 changed files with 216 additions and 135 deletions
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/***************************************************************************/ |
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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 2004 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_* 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, 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 */ |
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/* be used with FreeType in default mode (the library will simply */ |
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/* return an error later when trying to load the glyph). */ |
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/* */ |
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/* It also check that fields that 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 */ |
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/* level 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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/* validator structure */ |
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typedef struct FT_ValidatorRec_ |
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{ |
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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_jmp_buf jump_buffer; /* used for exception handling */ |
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} FT_ValidatorRec; |
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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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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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/* Use preprocessor prescan to pass FT_ERR_PREFIX. */ |
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/* */ |
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#define FT_INVALID( _prefix, _error ) FT_INVALID_( _prefix, _error ) |
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#define FT_INVALID_( _prefix, _error ) \ |
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ft_validator_error( valid, _prefix ## _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( FT_ERR_PREFIX, 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( FT_ERR_PREFIX, 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( FT_ERR_PREFIX, 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( FT_ERR_PREFIX, 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( FT_ERR_PREFIX, 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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