ref: d4f4b292ca9c8665ef938036340ff32bf5128755
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 );
}