ref: 1018d7a7091fd5e0433f501a3474cdc3fec322cc
dir: /libfreetype/otlgsub.c/
#include "otlgsub.h" #include "otlcommn.h" /************************************************************************/ /************************************************************************/ /***** *****/ /***** GSUB LOOKUP TYPE 1 *****/ /***** *****/ /************************************************************************/ /************************************************************************/ /* * 1: Single Substitution - Table format(s) * * This table is used to substiture individual glyph indices * with another one. There are only two sub-formats: * * Name Offset Size Description * ------------------------------------------ * format 0 2 sub-table format (1) * offset 2 2 offset to coverage table * delta 4 2 16-bit delta to apply on all * covered glyph indices * * Name Offset Size Description * ------------------------------------------ * format 0 2 sub-table format (2) * offset 2 2 offset to coverage table * count 4 2 coverage table count * substs[] 6 2*count substituted glyph indices, * */ static void otl_gsub_lookup1_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt format; OTL_CHECK( 2 ); format = OTL_NEXT_USHORT( p ); switch ( format ) { case 1: { OTL_UInt coverage; OTL_CHECK( 4 ); coverage = OTL_NEXT_USHORT( p ); otl_coverage_validate( table + coverage, valid ); } break; case 2: { OTL_UInt coverage, count; OTL_CHECK( 4 ); coverage = OTL_NEXT_USHORT( p ); count = OTL_NEXT_USHORT( p ); otl_coverage_validate( table + coverage, valid ); OTL_CHECK( 2*count ); /* NB: we don't check that there are at most 'count' */ /* elements in the coverage table. This is delayed */ /* to the lookup function... */ } break; default: OTL_INVALID_DATA; } } static OTL_Bool otl_gsub_lookup1_apply( OTL_Bytes table, OTL_Parser parser ) { OTL_Bytes p = table; OTL_Bytes coverage; OTL_UInt format, gindex, property; OTL_Int index; OTL_Bool subst = 0; if ( parser->context_len != 0xFFFF && parser->context_len < 1 ) goto Exit; gindex = otl_parser_get_gindex( parser ); if ( !otl_parser_check_property( parser, gindex, &property ) ) goto Exit; format = OTL_NEXT_USHORT(p); coverage = table + OTL_NEXT_USHORT(p); index = otl_coverage_lookup( coverage, gindex ); if ( index >= 0 ) { switch ( format ) { case 1: { OTL_Int delta = OTL_NEXT_SHORT(p); gindex = ( gindex + delta ) & 0xFFFF; otl_parser_replace_1( parser, gindex ); subst = 1; } break; case 2: { OTL_UInt count = OTL_NEXT_USHORT(p); if ( (OTL_UInt) index < count ) { p += index*2; otl_parser_replace_1( parser, OTL_PEEK_USHORT(p) ); subst = 1; } } break; default: ; } } Exit: return subst; } /************************************************************************/ /************************************************************************/ /***** *****/ /***** GSUB LOOKUP TYPE 2 *****/ /***** *****/ /************************************************************************/ /************************************************************************/ /* * 2: Multiple Substitution - Table format(s) * * Replaces a single glyph with one or more glyphs. * * Name Offset Size Description * ----------------------------------------------------------- * format 0 2 sub-table format (1) * offset 2 2 offset to coverage table * count 4 2 coverage table count * sequencess[] 6 2*count offsets to sequence items * * each sequence item has the following format: * * Name Offset Size Description * ----------------------------------------------------------- * count 0 2 number of replacement glyphs * gindices[] 2 2*count string of glyph indices */ static void otl_seq_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt count; OTL_CHECK( 2 ); count = OTL_NEXT_USHORT( p ); /* XXX: according to the spec, 'count' should be > 0 */ /* we can deal with these cases pretty well however */ OTL_CHECK( 2*count ); /* check glyph indices */ } static void otl_gsub_lookup2_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt format, coverage; OTL_CHECK( 2 ); format = OTL_NEXT_USHORT( p ); switch ( format ) { case 1: { OTL_UInt coverage, seq_count; OTL_CHECK( 4 ); coverage = OTL_NEXT_USHORT( p ); seq_count = OTL_NEXT_USHORT( p ); otl_coverage_validate( table + coverage, valid ); OTL_CHECK( seq_count*2 ); for ( ; seq_count > 0; seq_count-- ) otl_seq_validate( table + OTL_NEXT_USHORT( p ), valid ); } break; default: OTL_INVALID_DATA; } } static OTL_Bool otl_gsub_lookup2_apply( OTL_Bytes table, OTL_Parser parser ) { OTL_Bytes p = table; OTL_Bytes coverage, sequence; OTL_UInt format, gindex, index, property; OTL_Int index; OTL_Bool subst = 0; if ( context_len != 0xFFFF && context_len < 1 ) goto Exit; gindex = otl_parser_get_gindex( parser ); if ( !otl_parser_check_property( parser, gindex, &property ) ) goto Exit; p += 2; /* skip format */ coverage = table + OTL_NEXT_USHORT(p); seq_count = OTL_NEXT_USHORT(p); index = otl_coverage_lookup( coverage, gindex ); if ( (OTL_UInt) index >= seq_count ) goto Exit; p += index*2; sequence = table + OTL_PEEK_USHORT(p); p = sequence; count = OTL_NEXT_USHORT(p); otl_parser_replace_n( parser, count, p ); subst = 1; Exit: return subst; } /************************************************************************/ /************************************************************************/ /***** *****/ /***** GSUB LOOKUP TYPE 3 *****/ /***** *****/ /************************************************************************/ /************************************************************************/ /* * 3: Alternate Substitution - Table format(s) * * Replaces a single glyph by another one taken liberally * in a list of alternatives * * Name Offset Size Description * ----------------------------------------------------------- * format 0 2 sub-table format (1) * offset 2 2 offset to coverage table * count 4 2 coverage table count * alternates[] 6 2*count offsets to alternate items * * each alternate item has the following format: * * Name Offset Size Description * ----------------------------------------------------------- * count 0 2 number of replacement glyphs * gindices[] 2 2*count string of glyph indices, each one * is a valid alternative */ static void otl_alternate_set_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt count; OTL_CHECK( 2 ); count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*count ); /* XXX: check glyph indices */ } static void otl_gsub_lookup3_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt format, coverage; OTL_CHECK( 2 ); format = OTL_NEXT_USHORT( p ); switch ( format ) { case 1: { OTL_UInt coverage, count; OTL_CHECK( 4 ); coverage = OTL_NEXT_USHORT( p ); count = OTL_NEXT_USHORT( p ); otl_coverage_validate( table + coverage, valid ); OTL_CHECK( 2*count ); for ( ; count > 0; count-- ) otl_alternate_set_validate( table + OTL_NEXT_USHORT( p ), valid ); } break; default: OTL_INVALID_DATA; } } static OTL_Bool otl_gsub_lookup3_apply( OTL_Bytes table, OTL_Parser parser ) { OTL_Bytes p = table; OTL_Bytes coverage, alternates; OTL_UInt format, gindex, index, property; OTL_Int index; OTL_Bool subst = 0; OTL_GSUB_Alternate alternate = parser->alternate; if ( context_len != 0xFFFF && context_len < 1 ) goto Exit; if ( alternate == NULL ) goto Exit; gindex = otl_parser_get_gindex( parser ); if ( !otl_parser_check_property( parser, gindex, &property ) ) goto Exit; p += 2; /* skip format */ coverage = table + OTL_NEXT_USHORT(p); seq_count = OTL_NEXT_USHORT(p); index = otl_coverage_lookup( coverage, gindex ); if ( (OTL_UInt) index >= seq_count ) goto Exit; p += index*2; alternates = table + OTL_PEEK_USHORT(p); p = alternates; count = OTL_NEXT_USHORT(p); gindex = alternate->handler_func( gindex, count, p, alternate->handler_data ); otl_parser_replace_1( parser, gindex ); subst = 1; Exit: return subst; } /************************************************************************/ /************************************************************************/ /***** *****/ /***** GSUB LOOKUP TYPE 4 *****/ /***** *****/ /************************************************************************/ /************************************************************************/ static void otl_ligature_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_UInt glyph_id, count; OTL_CHECK( 4 ); glyph_id = OTL_NEXT_USHORT( p ); count = OTL_NEXT_USHORT( p ); if ( count == 0 ) OTL_INVALID_DATA; OTL_CHECK( 2*(count-1) ); /* XXX: check glyph indices */ } static void otl_ligature_set_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt count; OTL_CHECK( 2 ); count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*count ); for ( ; count > 0; count-- ) otl_ligature_validate( table + OTL_NEXT_USHORT( p ), valid ); } static void otl_gsub_lookup4_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt format, coverage; OTL_CHECK( 2 ); format = OTL_NEXT_USHORT( p ); switch ( format ) { case 1: { OTL_UInt coverage, count; OTL_CHECK( 4 ); coverage = OTL_NEXT_USHORT( p ); count = OTL_NEXT_USHORT( p ); otl_coverage_validate( table + coverage, valid ); OTL_CHECK( 2*count ); for ( ; count > 0; count-- ) otl_ligature_set_validate( table + OTL_NEXT_USHORT( p ), valid ); } break; default: OTL_INVALID_DATA; } } /************************************************************************/ /************************************************************************/ /***** *****/ /***** GSUB LOOKUP TYPE 5 *****/ /***** *****/ /************************************************************************/ /************************************************************************/ static void otl_sub_rule_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt glyph_count, subst_count; OTL_CHECK( 4 ); glyph_count = OTL_NEXT_USHORT( p ); subst_count = OTL_NEXT_USHORT( p ); if ( glyph_count == 0 ) OTL_INVALID_DATA; OTL_CHECK( (glyph_count-1)*2 + substcount*4 ); /* XXX: check glyph indices and subst lookups */ } static void otl_sub_rule_set_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt count; OTL_CHECK( 2 ); count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*count ); for ( ; count > 0; count-- ) otl_sub_rule_validate( table + OTL_NEXT_USHORT( p ), valid ); } static void otl_sub_class_rule_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_UInt glyph_count, subst_count; OTL_CHECK( 4 ); glyph_count = OTL_NEXT_USHORT( p ); subst_count = OTL_NEXT_USHORT( p ); if ( glyph_count == 0 ) OTL_INVALID_DATA; OTL_CHECK( (glyph_count-1)*2 + substcount*4 ); /* XXX: check glyph indices and subst lookups */ } static void otl_sub_class_rule_set_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt count; OTL_CHECK( 2 ); count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*count ); for ( ; count > 0; count-- ) otl_sub_class_rule_validate( table + OTL_NEXT_USHORT( p ), valid ); } static void otl_gsub_lookup5_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt format, coverage; OTL_CHECK( 2 ); format = OTL_NEXT_USHORT( p ); switch ( format ) { case 1: { OTL_UInt coverage, count; OTL_CHECK( 4 ); coverage = OTL_NEXT_USHORT( p ); count = OTL_NEXT_USHORT( p ); otl_coverage_validate( table + coverage, valid ); OTL_CHECK( 2*count ); for ( ; count > 0; count-- ) otl_sub_rule_set_validate( table + coverage, valid ); } break; case 2: { OTL_UInt coverage, class_def, count; OTL_CHECK( 6 ); coverage = OTL_NEXT_USHORT( p ); class_def = OTL_NEXT_USHORT( p ); count = OTL_NEXT_USHORT( p ); otl_coverage_validate ( table + coverage, valid ); otl_class_definition_validate( table + class_def, valid ); OTL_CHECK( 2*count ); for ( ; count > 0; count-- ) otl_sub_class_rule_set_validate( table + coveragen valid ); } break; case 3: { OTL_UInt glyph_count, subst_count, count; OTL_CHECK( 4 ); glyph_count = OTL_NEXT_USHORT( p ); subst_count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*glyph_count + 4*subst_count ); for ( count = glyph_count; count > 0; count-- ) otl_coverage_validate( table + OTL_NEXT_USHORT( p ), valid ); } break; default: OTL_INVALID_DATA; } } /************************************************************************/ /************************************************************************/ /***** *****/ /***** GSUB LOOKUP TYPE 6 *****/ /***** *****/ /************************************************************************/ /************************************************************************/ static void otl_chain_sub_rule_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt back_count, input_count, ahead_count, subst_count, count; OTL_CHECK( 2 ); back_count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*back_count+2 ); p += 2*back_count; input_count = OTL_NEXT_USHORT( p ); if ( input_count == 0 ) OTL_INVALID_DATA; OTL_CHECK( 2*input_count ); p += 2*(input_count-1); ahead_count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*ahead_count + 2 ); p += 2*ahead_count; count = OTL_NEXT_USHORT( p ); OTL_CHECK( 4*count ); /* XXX: check glyph indices and subst lookups */ } static void otl_chain_sub_rule_set_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt count; OTL_CHECK( 2 ); count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*count ); for ( ; count > 0; count-- ) otl_chain_sub_rule_validate( table + OTL_NEXT_USHORT( p ), valid ); } static void otl_chain_sub_class_rule_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt back_count, input_count, ahead_count, subst_count, count; OTL_CHECK( 2 ); back_count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*back_count+2 ); p += 2*back_count; input_count = OTL_NEXT_USHORT( p ); if ( input_count == 0 ) OTL_INVALID_DATA; OTL_CHECK( 2*input_count ); p += 2*(input_count-1); ahead_count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*ahead_count + 2 ); p += 2*ahead_count; count = OTL_NEXT_USHORT( p ); OTL_CHECK( 4*count ); /* XXX: check class indices and subst lookups */ } static void otl_chain_sub_class_set_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt count; OTL_CHECK( 2 ); count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*count ); for ( ; count > 0; count-- ) otl_chain_sub_rule_validate( table + OTL_NEXT_USHORT( p ), valid ); } static void otl_gsub_lookup6_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt format, coverage; OTL_CHECK( 2 ); format = OTL_NEXT_USHORT( p ); switch ( format ) { case 1: { OTL_UInt coverage, count; OTL_CHECK( 4 ); coverage = OTL_NEXT_USHORT( p ); count = OTL_NEXT_USHORT( p ); otl_coverage_validate( table + coverage, valid ); OTL_CHECK( 2*count ); for ( ; count > 0; count-- ) otl_chain_sub_rule_set_validate( table + coverage, valid ); } break; case 2: { OTL_UInt coverage, back_class, input_class, ahead_class, count; OTL_CHECK( 10 ); coverage = OTL_NEXT_USHORT( p ); back_class = OTL_NEXT_USHORT( p ); input_class = OTL_NEXT_USHORT( p ); ahead_class = OTL_NEXT_USHORT( p ); count = OTL_NEXT_USHORT( p ); otl_coverage_validate( table + coverage, valid ); otl_class_definition_validate( table + back_class, valid ); otl_class_definition_validate( table + input_class, valid ); otl_class_definition_validate( table + ahead_class, valid ); OTL_CHECK( 2*count ); for ( ; count > 0; count-- ) otl_chain_sub_class_set( table + OTL_NEXT_USHORT( p ), valid ); } break; case 3: { OTL_UInt back_count, input_count, ahead_count, subst_count, count; OTL_CHECK( 2 ); back_count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*back_count+2 ); for ( count = back_count; count > 0; count-- ) otl_coverage_validate( table + OTL_NEXT_USHORT( p ), valid ); input_count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*input_count+2 ); for ( count = input_count; count > 0; count-- ) otl_coverage_validate( table + OTL_NEXT_USHORT( p ), valid ); ahead_count = OTL_NEXT_USHORT( p ); OTL_CHECK( 2*ahead_count+2 ); for ( count = ahead_count; count > 0; count-- ) otl_coverage_validate( table + OTL_NEXT_USHORT( p ), valid ); subst_count = OTL_NEXT_USHORT( p ); OTL_CHECK( subst_count*4 ); } break; default: OTL_INVALID_DATA; } } /************************************************************************/ /************************************************************************/ /***** *****/ /***** GSUB LOOKUP TYPE 6 *****/ /***** *****/ /************************************************************************/ /************************************************************************/ static void otl_gsub_lookup7_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt format, coverage; OTL_CHECK( 2 ); format = OTL_NEXT_USHORT( p ); switch ( format ) { case 1: { OTL_UInt lookup_type, lookup_offset; OTL_ValidateFunc validate; OTL_CHECK( 6 ); lookup_type = OTL_NEXT_USHORT( p ); lookup_offset = OTL_NEXT_ULONG( p ); if ( lookup_type == 0 || lookup_type >= 7 ) OTL_INVALID_DATA; validate = otl_gsub_validate_funcs[ lookup_type-1 ]; validate( table + lookup_offset, valid ); } break; default: OTL_INVALID_DATA; } } static const OTL_ValidateFunc otl_gsub_validate_funcs[ 7 ] = { otl_gsub_lookup1_validate, otl_gsub_lookup2_validate, otl_gsub_lookup3_validate, otl_gsub_lookup4_validate, otl_gsub_lookup5_validate, otl_gsub_lookup6_validate }; /************************************************************************/ /************************************************************************/ /***** *****/ /***** GSUB TABLE *****/ /***** *****/ /************************************************************************/ /************************************************************************/ OTL_LOCALDEF( void ) otl_gsub_validate( OTL_Bytes table, OTL_Validator valid ) { OTL_Bytes p = table; OTL_UInt scripts, features, lookups; OTL_CHECK( 10 ); if ( OTL_NEXT_USHORT( p ) != 0x10000UL ) OTL_INVALID_DATA; scripts = OTL_NEXT_USHORT( p ); features = OTL_NEXT_USHORT( p ); lookups = OTL_NEXT_USHORT( p ); otl_script_list_validate ( table + scripts, valid ); otl_feature_list_validate( table + features, valid ); otl_lookup_list_validate( table + lookups, 7, otl_gsub_validate_funcs, valid ); }