| /***************************************************************************/ |
| /* */ |
| /* otvgsub.c */ |
| /* */ |
| /* OpenType GSUB table validation (body). */ |
| /* */ |
| /* Copyright 2004-2015 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 otvalid->glyph_count */ |
| |
| static void |
| otv_SingleSubst_validate( FT_Bytes table, |
| OTV_Validator otvalid ) |
| { |
| 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, otvalid, -1 ); |
| |
| idx = (FT_Long)otv_Coverage_get_first( Coverage ) + DeltaGlyphID; |
| if ( idx < 0 ) |
| FT_INVALID_DATA; |
| |
| idx = (FT_Long)otv_Coverage_get_last( Coverage ) + DeltaGlyphID; |
| if ( (FT_UInt)idx >= otvalid->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, |
| otvalid, |
| (FT_Int)GlyphCount ); |
| |
| OTV_LIMIT_CHECK( GlyphCount * 2 ); |
| |
| /* Substitute */ |
| for ( ; GlyphCount > 0; GlyphCount-- ) |
| if ( FT_NEXT_USHORT( p ) >= otvalid->glyph_count ) |
| FT_INVALID_GLYPH_ID; |
| } |
| break; |
| |
| default: |
| FT_INVALID_FORMAT; |
| } |
| |
| OTV_EXIT; |
| } |
| |
| |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /***** *****/ |
| /***** GSUB LOOKUP TYPE 2 *****/ |
| /***** *****/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| |
| /* sets otvalid->extra1 (glyph count) */ |
| |
| static void |
| otv_MultipleSubst_validate( FT_Bytes table, |
| OTV_Validator otvalid ) |
| { |
| 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: |
| otvalid->extra1 = otvalid->glyph_count; |
| OTV_NEST2( MultipleSubstFormat1, Sequence ); |
| OTV_RUN( table, otvalid ); |
| break; |
| |
| default: |
| FT_INVALID_FORMAT; |
| } |
| |
| OTV_EXIT; |
| } |
| |
| |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /***** *****/ |
| /***** GSUB LOOKUP TYPE 3 *****/ |
| /***** *****/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| |
| /* sets otvalid->extra1 (glyph count) */ |
| |
| static void |
| otv_AlternateSubst_validate( FT_Bytes table, |
| OTV_Validator otvalid ) |
| { |
| 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: |
| otvalid->extra1 = otvalid->glyph_count; |
| OTV_NEST2( AlternateSubstFormat1, AlternateSet ); |
| OTV_RUN( table, otvalid ); |
| break; |
| |
| default: |
| FT_INVALID_FORMAT; |
| } |
| |
| OTV_EXIT; |
| } |
| |
| |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /***** *****/ |
| /***** GSUB LOOKUP TYPE 4 *****/ |
| /***** *****/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| |
| #define LigatureFunc otv_Ligature_validate |
| |
| /* uses otvalid->glyph_count */ |
| |
| static void |
| otv_Ligature_validate( FT_Bytes table, |
| OTV_Validator otvalid ) |
| { |
| FT_Bytes p = table; |
| FT_UInt LigatureGlyph, CompCount; |
| |
| |
| OTV_ENTER; |
| |
| OTV_LIMIT_CHECK( 4 ); |
| LigatureGlyph = FT_NEXT_USHORT( p ); |
| if ( LigatureGlyph >= otvalid->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 otvalid ) |
| { |
| 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, otvalid ); |
| break; |
| |
| default: |
| FT_INVALID_FORMAT; |
| } |
| |
| OTV_EXIT; |
| } |
| |
| |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /***** *****/ |
| /***** GSUB LOOKUP TYPE 5 *****/ |
| /***** *****/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| |
| /* sets otvalid->extra1 (lookup count) */ |
| |
| static void |
| otv_ContextSubst_validate( FT_Bytes table, |
| OTV_Validator otvalid ) |
| { |
| 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 */ |
| |
| otvalid->extra1 = otvalid->lookup_count; |
| OTV_NEST3( ContextSubstFormat1, SubRuleSet, SubRule ); |
| OTV_RUN( table, otvalid ); |
| 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, otvalid ); |
| break; |
| |
| case 3: |
| OTV_NEST1( ContextSubstFormat3 ); |
| OTV_RUN( table, otvalid ); |
| break; |
| |
| default: |
| FT_INVALID_FORMAT; |
| } |
| |
| OTV_EXIT; |
| } |
| |
| |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /***** *****/ |
| /***** GSUB LOOKUP TYPE 6 *****/ |
| /***** *****/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| |
| /* sets otvalid->extra1 (lookup count) */ |
| |
| static void |
| otv_ChainContextSubst_validate( FT_Bytes table, |
| OTV_Validator otvalid ) |
| { |
| 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 */ |
| |
| otvalid->extra1 = otvalid->lookup_count; |
| OTV_NEST3( ChainContextSubstFormat1, |
| ChainSubRuleSet, ChainSubRule ); |
| OTV_RUN( table, otvalid ); |
| 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, otvalid ); |
| break; |
| |
| case 3: |
| OTV_NEST1( ChainContextSubstFormat3 ); |
| OTV_RUN( table, otvalid ); |
| break; |
| |
| default: |
| FT_INVALID_FORMAT; |
| } |
| |
| OTV_EXIT; |
| } |
| |
| |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /***** *****/ |
| /***** GSUB LOOKUP TYPE 7 *****/ |
| /***** *****/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| |
| /* uses otvalid->type_funcs */ |
| |
| static void |
| otv_ExtensionSubst_validate( FT_Bytes table, |
| OTV_Validator otvalid ) |
| { |
| 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 = otvalid->type_funcs[ExtensionLookupType - 1]; |
| validate( table + ExtensionOffset, otvalid ); |
| } |
| break; |
| |
| default: |
| FT_INVALID_FORMAT; |
| } |
| |
| OTV_EXIT; |
| } |
| |
| |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /***** *****/ |
| /***** GSUB LOOKUP TYPE 8 *****/ |
| /***** *****/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| |
| /* uses otvalid->glyph_count */ |
| |
| static void |
| otv_ReverseChainSingleSubst_validate( FT_Bytes table, |
| OTV_Validator otvalid ) |
| { |
| 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, otvalid, -1 ); |
| |
| OTV_LIMIT_CHECK( BacktrackGlyphCount * 2 + 2 ); |
| |
| for ( ; BacktrackGlyphCount > 0; BacktrackGlyphCount-- ) |
| otv_Coverage_validate( table + FT_NEXT_USHORT( p ), otvalid, -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 ), otvalid, -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 ) >= otvalid->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 otvalid->type_count */ |
| /* sets otvalid->type_funcs */ |
| /* sets otvalid->glyph_count */ |
| |
| FT_LOCAL_DEF( void ) |
| otv_GSUB_validate( FT_Bytes table, |
| FT_UInt glyph_count, |
| FT_Validator ftvalid ) |
| { |
| OTV_ValidatorRec otvalidrec; |
| OTV_Validator otvalid = &otvalidrec; |
| FT_Bytes p = table; |
| FT_UInt ScriptList, FeatureList, LookupList; |
| |
| |
| otvalid->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 ); |
| |
| otvalid->type_count = 8; |
| otvalid->type_funcs = (OTV_Validate_Func*)otv_gsub_validate_funcs; |
| otvalid->glyph_count = glyph_count; |
| |
| otv_LookupList_validate( table + LookupList, |
| otvalid ); |
| otv_FeatureList_validate( table + FeatureList, table + LookupList, |
| otvalid ); |
| otv_ScriptList_validate( table + ScriptList, table + FeatureList, |
| otvalid ); |
| |
| FT_TRACE4(( "\n" )); |
| } |
| |
| |
| /* END */ |
