/modules/freetype2/src/otvalid/otvgsub.c
C | 585 lines | 313 code | 160 blank | 112 comment | 26 complexity | a3ffb11e5de3447f041dc612a880e83d MD5 | raw file
Possible License(s): GPL-2.0, JSON, 0BSD, LGPL-3.0, AGPL-1.0, MIT, MPL-2.0-no-copyleft-exception, BSD-3-Clause, LGPL-2.1, Apache-2.0
- /***************************************************************************/
- /* */
- /* otvgsub.c */
- /* */
- /* OpenType GSUB table validation (body). */
- /* */
- /* Copyright 2004, 2005, 2007 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. */
- /* */
- /***************************************************************************/
- #include "otvalid.h"
- #include "otvcommn.h"
- /*************************************************************************/
- /* */
- /* The macro FT_COMPONENT is used in trace mode. It is an implicit */
- /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */
- /* messages during execution. */
- /* */
- #undef FT_COMPONENT
- #define FT_COMPONENT trace_otvgsub
- /*************************************************************************/
- /*************************************************************************/
- /***** *****/
- /***** GSUB LOOKUP TYPE 1 *****/
- /***** *****/
- /*************************************************************************/
- /*************************************************************************/
- /* uses valid->glyph_count */
- static void
- otv_SingleSubst_validate( FT_Bytes table,
- OTV_Validator valid )
- {
- FT_Bytes p = table;
- FT_UInt SubstFormat;
- OTV_NAME_ENTER( "SingleSubst" );
- OTV_LIMIT_CHECK( 2 );
- SubstFormat = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (format %d)\n", SubstFormat ));
- switch ( SubstFormat )
- {
- case 1: /* SingleSubstFormat1 */
- {
- FT_Bytes Coverage;
- FT_Int DeltaGlyphID;
- FT_Long idx;
- OTV_LIMIT_CHECK( 4 );
- Coverage = table + FT_NEXT_USHORT( p );
- DeltaGlyphID = FT_NEXT_SHORT( p );
- otv_Coverage_validate( Coverage, valid, -1 );
- idx = otv_Coverage_get_first( Coverage ) + DeltaGlyphID;
- if ( idx < 0 )
- FT_INVALID_DATA;
- idx = otv_Coverage_get_last( Coverage ) + DeltaGlyphID;
- if ( (FT_UInt)idx >= valid->glyph_count )
- FT_INVALID_DATA;
- }
- break;
- case 2: /* SingleSubstFormat2 */
- {
- FT_UInt Coverage, GlyphCount;
- OTV_LIMIT_CHECK( 4 );
- Coverage = FT_NEXT_USHORT( p );
- GlyphCount = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (GlyphCount = %d)\n", GlyphCount ));
- otv_Coverage_validate( table + Coverage, valid, GlyphCount );
- OTV_LIMIT_CHECK( GlyphCount * 2 );
- /* Substitute */
- for ( ; GlyphCount > 0; GlyphCount-- )
- if ( FT_NEXT_USHORT( p ) >= valid->glyph_count )
- FT_INVALID_GLYPH_ID;
- }
- break;
- default:
- FT_INVALID_FORMAT;
- }
- OTV_EXIT;
- }
- /*************************************************************************/
- /*************************************************************************/
- /***** *****/
- /***** GSUB LOOKUP TYPE 2 *****/
- /***** *****/
- /*************************************************************************/
- /*************************************************************************/
- /* sets valid->extra1 (glyph count) */
- static void
- otv_MultipleSubst_validate( FT_Bytes table,
- OTV_Validator valid )
- {
- FT_Bytes p = table;
- FT_UInt SubstFormat;
- OTV_NAME_ENTER( "MultipleSubst" );
- OTV_LIMIT_CHECK( 2 );
- SubstFormat = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (format %d)\n", SubstFormat ));
- switch ( SubstFormat )
- {
- case 1:
- valid->extra1 = valid->glyph_count;
- OTV_NEST2( MultipleSubstFormat1, Sequence );
- OTV_RUN( table, valid );
- break;
- default:
- FT_INVALID_FORMAT;
- }
- OTV_EXIT;
- }
- /*************************************************************************/
- /*************************************************************************/
- /***** *****/
- /***** GSUB LOOKUP TYPE 3 *****/
- /***** *****/
- /*************************************************************************/
- /*************************************************************************/
- /* sets valid->extra1 (glyph count) */
- static void
- otv_AlternateSubst_validate( FT_Bytes table,
- OTV_Validator valid )
- {
- FT_Bytes p = table;
- FT_UInt SubstFormat;
- OTV_NAME_ENTER( "AlternateSubst" );
- OTV_LIMIT_CHECK( 2 );
- SubstFormat = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (format %d)\n", SubstFormat ));
- switch ( SubstFormat )
- {
- case 1:
- valid->extra1 = valid->glyph_count;
- OTV_NEST2( AlternateSubstFormat1, AlternateSet );
- OTV_RUN( table, valid );
- break;
- default:
- FT_INVALID_FORMAT;
- }
- OTV_EXIT;
- }
- /*************************************************************************/
- /*************************************************************************/
- /***** *****/
- /***** GSUB LOOKUP TYPE 4 *****/
- /***** *****/
- /*************************************************************************/
- /*************************************************************************/
- #define LigatureFunc otv_Ligature_validate
- /* uses valid->glyph_count */
- static void
- otv_Ligature_validate( FT_Bytes table,
- OTV_Validator valid )
- {
- FT_Bytes p = table;
- FT_UInt LigatureGlyph, CompCount;
- OTV_ENTER;
- OTV_LIMIT_CHECK( 4 );
- LigatureGlyph = FT_NEXT_USHORT( p );
- if ( LigatureGlyph >= valid->glyph_count )
- FT_INVALID_DATA;
- CompCount = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (CompCount = %d)\n", CompCount ));
- if ( CompCount == 0 )
- FT_INVALID_DATA;
- CompCount--;
- OTV_LIMIT_CHECK( CompCount * 2 ); /* Component */
- /* no need to check the Component glyph indices */
- OTV_EXIT;
- }
- static void
- otv_LigatureSubst_validate( FT_Bytes table,
- OTV_Validator valid )
- {
- FT_Bytes p = table;
- FT_UInt SubstFormat;
- OTV_NAME_ENTER( "LigatureSubst" );
- OTV_LIMIT_CHECK( 2 );
- SubstFormat = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (format %d)\n", SubstFormat ));
- switch ( SubstFormat )
- {
- case 1:
- OTV_NEST3( LigatureSubstFormat1, LigatureSet, Ligature );
- OTV_RUN( table, valid );
- break;
- default:
- FT_INVALID_FORMAT;
- }
- OTV_EXIT;
- }
- /*************************************************************************/
- /*************************************************************************/
- /***** *****/
- /***** GSUB LOOKUP TYPE 5 *****/
- /***** *****/
- /*************************************************************************/
- /*************************************************************************/
- /* sets valid->extra1 (lookup count) */
- static void
- otv_ContextSubst_validate( FT_Bytes table,
- OTV_Validator valid )
- {
- FT_Bytes p = table;
- FT_UInt SubstFormat;
- OTV_NAME_ENTER( "ContextSubst" );
- OTV_LIMIT_CHECK( 2 );
- SubstFormat = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (format %d)\n", SubstFormat ));
- switch ( SubstFormat )
- {
- case 1:
- /* no need to check glyph indices/classes used as input for these */
- /* context rules since even invalid glyph indices/classes return */
- /* meaningful results */
- valid->extra1 = valid->lookup_count;
- OTV_NEST3( ContextSubstFormat1, SubRuleSet, SubRule );
- OTV_RUN( table, valid );
- break;
- case 2:
- /* no need to check glyph indices/classes used as input for these */
- /* context rules since even invalid glyph indices/classes return */
- /* meaningful results */
- OTV_NEST3( ContextSubstFormat2, SubClassSet, SubClassRule );
- OTV_RUN( table, valid );
- break;
- case 3:
- OTV_NEST1( ContextSubstFormat3 );
- OTV_RUN( table, valid );
- break;
- default:
- FT_INVALID_FORMAT;
- }
- OTV_EXIT;
- }
- /*************************************************************************/
- /*************************************************************************/
- /***** *****/
- /***** GSUB LOOKUP TYPE 6 *****/
- /***** *****/
- /*************************************************************************/
- /*************************************************************************/
- /* sets valid->extra1 (lookup count) */
- static void
- otv_ChainContextSubst_validate( FT_Bytes table,
- OTV_Validator valid )
- {
- FT_Bytes p = table;
- FT_UInt SubstFormat;
- OTV_NAME_ENTER( "ChainContextSubst" );
- OTV_LIMIT_CHECK( 2 );
- SubstFormat = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (format %d)\n", SubstFormat ));
- switch ( SubstFormat )
- {
- case 1:
- /* no need to check glyph indices/classes used as input for these */
- /* context rules since even invalid glyph indices/classes return */
- /* meaningful results */
- valid->extra1 = valid->lookup_count;
- OTV_NEST3( ChainContextSubstFormat1,
- ChainSubRuleSet, ChainSubRule );
- OTV_RUN( table, valid );
- break;
- case 2:
- /* no need to check glyph indices/classes used as input for these */
- /* context rules since even invalid glyph indices/classes return */
- /* meaningful results */
- OTV_NEST3( ChainContextSubstFormat2,
- ChainSubClassSet, ChainSubClassRule );
- OTV_RUN( table, valid );
- break;
- case 3:
- OTV_NEST1( ChainContextSubstFormat3 );
- OTV_RUN( table, valid );
- break;
- default:
- FT_INVALID_FORMAT;
- }
- OTV_EXIT;
- }
- /*************************************************************************/
- /*************************************************************************/
- /***** *****/
- /***** GSUB LOOKUP TYPE 7 *****/
- /***** *****/
- /*************************************************************************/
- /*************************************************************************/
- /* uses valid->type_funcs */
- static void
- otv_ExtensionSubst_validate( FT_Bytes table,
- OTV_Validator valid )
- {
- FT_Bytes p = table;
- FT_UInt SubstFormat;
- OTV_NAME_ENTER( "ExtensionSubst" );
- OTV_LIMIT_CHECK( 2 );
- SubstFormat = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (format %d)\n", SubstFormat ));
- switch ( SubstFormat )
- {
- case 1: /* ExtensionSubstFormat1 */
- {
- FT_UInt ExtensionLookupType;
- FT_ULong ExtensionOffset;
- OTV_Validate_Func validate;
- OTV_LIMIT_CHECK( 6 );
- ExtensionLookupType = FT_NEXT_USHORT( p );
- ExtensionOffset = FT_NEXT_ULONG( p );
- if ( ExtensionLookupType == 0 ||
- ExtensionLookupType == 7 ||
- ExtensionLookupType > 8 )
- FT_INVALID_DATA;
- validate = valid->type_funcs[ExtensionLookupType - 1];
- validate( table + ExtensionOffset, valid );
- }
- break;
- default:
- FT_INVALID_FORMAT;
- }
- OTV_EXIT;
- }
- /*************************************************************************/
- /*************************************************************************/
- /***** *****/
- /***** GSUB LOOKUP TYPE 8 *****/
- /***** *****/
- /*************************************************************************/
- /*************************************************************************/
- /* uses valid->glyph_count */
- static void
- otv_ReverseChainSingleSubst_validate( FT_Bytes table,
- OTV_Validator valid )
- {
- FT_Bytes p = table, Coverage;
- FT_UInt SubstFormat;
- FT_UInt BacktrackGlyphCount, LookaheadGlyphCount, GlyphCount;
- OTV_NAME_ENTER( "ReverseChainSingleSubst" );
- OTV_LIMIT_CHECK( 2 );
- SubstFormat = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (format %d)\n", SubstFormat ));
- switch ( SubstFormat )
- {
- case 1: /* ReverseChainSingleSubstFormat1 */
- OTV_LIMIT_CHECK( 4 );
- Coverage = table + FT_NEXT_USHORT( p );
- BacktrackGlyphCount = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (BacktrackGlyphCount = %d)\n", BacktrackGlyphCount ));
- otv_Coverage_validate( Coverage, valid, -1 );
- OTV_LIMIT_CHECK( BacktrackGlyphCount * 2 + 2 );
- for ( ; BacktrackGlyphCount > 0; BacktrackGlyphCount-- )
- otv_Coverage_validate( table + FT_NEXT_USHORT( p ), valid, -1 );
- LookaheadGlyphCount = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (LookaheadGlyphCount = %d)\n", LookaheadGlyphCount ));
- OTV_LIMIT_CHECK( LookaheadGlyphCount * 2 + 2 );
- for ( ; LookaheadGlyphCount > 0; LookaheadGlyphCount-- )
- otv_Coverage_validate( table + FT_NEXT_USHORT( p ), valid, -1 );
- GlyphCount = FT_NEXT_USHORT( p );
- OTV_TRACE(( " (GlyphCount = %d)\n", GlyphCount ));
- if ( GlyphCount != otv_Coverage_get_count( Coverage ) )
- FT_INVALID_DATA;
- OTV_LIMIT_CHECK( GlyphCount * 2 );
- /* Substitute */
- for ( ; GlyphCount > 0; GlyphCount-- )
- if ( FT_NEXT_USHORT( p ) >= valid->glyph_count )
- FT_INVALID_DATA;
- break;
- default:
- FT_INVALID_FORMAT;
- }
- OTV_EXIT;
- }
- static const OTV_Validate_Func otv_gsub_validate_funcs[8] =
- {
- otv_SingleSubst_validate,
- otv_MultipleSubst_validate,
- otv_AlternateSubst_validate,
- otv_LigatureSubst_validate,
- otv_ContextSubst_validate,
- otv_ChainContextSubst_validate,
- otv_ExtensionSubst_validate,
- otv_ReverseChainSingleSubst_validate
- };
- /*************************************************************************/
- /*************************************************************************/
- /***** *****/
- /***** GSUB TABLE *****/
- /***** *****/
- /*************************************************************************/
- /*************************************************************************/
- /* sets valid->type_count */
- /* sets valid->type_funcs */
- /* sets valid->glyph_count */
- FT_LOCAL_DEF( void )
- otv_GSUB_validate( FT_Bytes table,
- FT_UInt glyph_count,
- FT_Validator ftvalid )
- {
- OTV_ValidatorRec validrec;
- OTV_Validator valid = &validrec;
- FT_Bytes p = table;
- FT_UInt ScriptList, FeatureList, LookupList;
- valid->root = ftvalid;
- FT_TRACE3(( "validating GSUB table\n" ));
- OTV_INIT;
- OTV_LIMIT_CHECK( 10 );
- if ( FT_NEXT_ULONG( p ) != 0x10000UL ) /* Version */
- FT_INVALID_FORMAT;
- ScriptList = FT_NEXT_USHORT( p );
- FeatureList = FT_NEXT_USHORT( p );
- LookupList = FT_NEXT_USHORT( p );
- valid->type_count = 8;
- valid->type_funcs = (OTV_Validate_Func*)otv_gsub_validate_funcs;
- valid->glyph_count = glyph_count;
- otv_LookupList_validate( table + LookupList,
- valid );
- otv_FeatureList_validate( table + FeatureList, table + LookupList,
- valid );
- otv_ScriptList_validate( table + ScriptList, table + FeatureList,
- valid );
- FT_TRACE4(( "\n" ));
- }
- /* END */