ref: 606901dc5da9cb09acb5593c5cf74ce1b52ca6e2
dir: /libfreetype/otlcommn.c/
/***************************************************************************/
/* */
/* otlcommn.c */
/* */
/* OpenType layout support, common tables (body). */
/* */
/* Copyright 2002 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 "otlayout.h"
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** COVERAGE TABLE *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_coverage_validate( OTL_Bytes table,
OTL_Validator valid )
{
OTL_Bytes p;
OTL_UInt format;
if ( table + 4 > valid->limit )
OTL_INVALID_TOO_SHORT;
format = OTL_NEXT_USHORT( p );
switch ( format )
{
case 1:
{
OTL_UInt count = OTL_NEXT_USHORT( p );
if ( p + count * 2 >= valid->limit )
OTL_INVALID_TOO_SHORT;
/* XXX: check glyph indices */
}
break;
case 2:
{
OTL_UInt n, num_ranges = OTL_NEXT_USHORT( p );
OTL_UInt start, end, start_cover, total = 0, last = 0;
if ( p + num_ranges * 6 >= valid->limit )
OTL_INVALID_TOO_SHORT;
for ( n = 0; n < num_ranges; n++ )
{
start = OTL_NEXT_USHORT( p );
end = OTL_NEXT_USHORT( p );
start_cover = OTL_NEXT_USHORT( p );
if ( start > end || start_cover != total )
OTL_INVALID_DATA;
if ( n > 0 && start <= last )
OTL_INVALID_DATA;
total += end - start + 1;
last = end;
}
}
break;
default:
OTL_INVALID_FORMAT;
}
}
OTL_LOCALDEF( OTL_UInt )
otl_coverage_get_count( OTL_Bytes table )
{
OTL_Bytes p = table;
OTL_UInt format = OTL_NEXT_USHORT( p );
OTL_UInt count = OTL_NEXT_USHORT( p );
OTL_UInt result = 0;
switch ( format )
{
case 1:
return count;
case 2:
{
OTL_UInt start, end;
for ( ; count > 0; count-- )
{
start = OTL_NEXT_USHORT( p );
end = OTL_NEXT_USHORT( p );
p += 2; /* skip start_index */
result += end - start + 1;
}
}
break;
default:
;
}
return result;
}
OTL_LOCALDEF( OTL_Int )
otl_coverage_get_index( OTL_Bytes table,
OTL_UInt glyph_index )
{
OTL_Bytes p = table;
OTL_UInt format = OTL_NEXT_USHORT( p );
OTL_UInt count = OTL_NEXT_USHORT( p );
switch ( format )
{
case 1:
{
OTL_UInt min = 0, max = count, mid, gindex;
table += 4;
while ( min < max )
{
mid = ( min + max ) >> 1;
p = table + 2 * mid;
gindex = OTL_PEEK_USHORT( p );
if ( glyph_index == gindex )
return (OTL_Int)mid;
if ( glyph_index < gindex )
max = mid;
else
min = mid + 1;
}
}
break;
case 2:
{
OTL_UInt min = 0, max = count, mid;
OTL_UInt start, end, delta, start_cover;
table += 4;
while ( min < max )
{
mid = ( min + max ) >> 1;
p = table + 6 * mid;
start = OTL_NEXT_USHORT( p );
end = OTL_NEXT_USHORT( p );
if ( glyph_index < start )
max = mid;
else if ( glyph_index > end )
min = mid + 1;
else
return (OTL_Int)( glyph_index + OTL_NEXT_USHORT( p ) - start );
}
}
break;
default:
;
}
return -1;
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** CLASS DEFINITION TABLE *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_class_definition_validate( OTL_Bytes table,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt format;
if ( p + 4 > valid->limit )
OTL_INVALID_TOO_SHORT;
format = OTL_NEXT_USHORT( p );
switch ( format )
{
case 1:
{
OTL_UInt count, start = OTL_NEXT_USHORT( p );
if ( p + 2 > valid->limit )
OTL_INVALID_TOO_SHORT;
count = OTL_NEXT_USHORT( p );
if ( p + count * 2 > valid->limit )
OTL_INVALID_TOO_SHORT;
/* XXX: check glyph indices */
}
break;
case 2:
{
OTL_UInt n, num_ranges = OTL_NEXT_USHORT( p );
OTL_UInt start, end, value, last = 0;
if ( p + num_ranges * 6 > valid->limit )
OTL_INVALID_TOO_SHORT;
for ( n = 0; n < num_ranges; n++ )
{
start = OTL_NEXT_USHORT( p );
end = OTL_NEXT_USHORT( p );
value = OTL_NEXT_USHORT( p ); /* ignored */
if ( start > end || ( n > 0 && start <= last ) )
OTL_INVALID_DATA;
last = end;
}
}
break;
default:
OTL_INVALID_FORMAT;
}
}
OTL_LOCALDEF( OTL_UInt )
otl_class_definition_get_value( OTL_Bytes table,
OTL_UInt glyph_index )
{
OTL_Bytes p = table;
OTL_UInt format = OTL_NEXT_USHORT( p );
switch ( format )
{
case 1:
{
OTL_UInt start = OTL_NEXT_USHORT( p );
OTL_UInt count = OTL_NEXT_USHORT( p );
OTL_UInt idx = (OTL_UInt)( glyph_index - start );
if ( idx < count )
{
p += 2 * idx;
return OTL_PEEK_USHORT( p );
}
}
break;
case 2:
{
OTL_UInt count = OTL_NEXT_USHORT( p );
OTL_UInt min = 0, max = count, mid, gindex;
table += 4;
while ( min < max )
{
mid = ( min + max ) >> 1;
p = table + 6 * mid;
start = OTL_NEXT_USHORT( p );
end = OTL_NEXT_USHORT( p );
if ( glyph_index < start )
max = mid;
else if ( glyph_index > end )
min = mid + 1;
else
return OTL_PEEK_USHORT( p );
}
}
break;
default:
;
}
return 0;
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** DEVICE TABLE *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_device_table_validate( OTL_Bytes table,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt start, end, count, format, count;
if ( p + 8 > valid->limit )
OTL_INVALID_TOO_SHORT;
start = OTL_NEXT_USHORT( p );
end = OTL_NEXT_USHORT( p );
format = OTL_NEXT_USHORT( p );
if ( format < 1 || format > 3 || end < start )
OTL_INVALID_DATA;
count = (OTL_UInt)( end - start + 1 );
if ( p + ( ( 1 << format ) * count ) / 8 > valid->limit )
OTL_INVALID_TOO_SHORT;
}
OTL_LOCALDEF( OTL_UInt )
otl_device_table_get_start( OTL_Bytes table )
{
OTL_Bytes p = table;
return OTL_PEEK_USHORT( p );
}
OTL_LOCALDEF( OTL_UInt )
otl_device_table_get_end( OTL_Bytes table )
{
OTL_Bytes p = table + 2;
return OTL_PEEK_USHORT( p );
}
OTL_LOCALDEF( OTL_Int )
otl_device_table_get_delta( OTL_Bytes table,
OTL_UInt size )
{
OTL_Bytes p = table;
OTL_Int result = 0;
OTL_UInt start, end, format, idx, value;
start = OTL_NEXT_USHORT( p );
end = OTL_NEXT_USHORT( p );
format = OTL_NEXT_USHORT( p );
if ( size >= start && size <= end )
{
/* we could do that with clever bit operations, but a switch is */
/* much simpler to understand and maintain */
/* */
switch ( format )
{
case 1:
idx = (OTL_UInt)( ( size - start ) * 2 );
p += idx / 16;
value = OTL_PEEK_USHORT( p );
shift = idx & 15;
result = (OTL_Short)( value << shift ) >> ( 14 - shift );
break;
case 2:
idx = (OTL_UInt)( ( size - start ) * 4 );
p += idx / 16;
value = OTL_PEEK_USHORT( p );
shift = idx & 15;
result = (OTL_Short)( value << shift ) >> ( 12 - shift );
break;
case 3:
idx = (OTL_UInt)( ( size - start ) * 8 );
p += idx / 16;
value = OTL_PEEK_USHORT( p );
shift = idx & 15;
result = (OTL_Short)( value << shift ) >> ( 8 - shift );
break;
default:
;
}
}
return result;
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** LOOKUP LISTS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_lookup_validate( OTL_Bytes table,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt num_tables;
if ( table + 6 > valid->limit )
OTL_INVALID_TOO_SHORT;
p += 4;
num_tables = OTL_NEXT_USHORT( p );
if ( p + num_tables * 2 > valid->limit )
OTL_INVALID_TOO_SHORT;
for ( ; num_tables > 0; num_tables-- )
{
offset = OTL_NEXT_USHORT( p );
if ( table + offset >= valid->limit )
OTL_INVALID_OFFSET;
}
/* XXX: check sub-tables? */
}
OTL_LOCALDEF( OTL_UInt )
otl_lookup_get_count( OTL_Bytes table )
{
OTL_Bytes p = table + 4;
return OTL_PEEK_USHORT( p );
}
OTL_LOCALDEF( OTL_Bytes )
otl_lookup_get_table( OTL_Bytes table,
OTL_UInt idx )
{
OTL_Bytes p, result = NULL;
OTL_UInt count;
p = table + 4;
count = OTL_NEXT_USHORT( p );
if ( idx < count )
{
p += idx * 2;
result = table + OTL_PEEK_USHORT( p );
}
return result;
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** LOOKUP LISTS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_lookup_list_validate( OTL_Bytes table,
OTL_Validator valid )
{
OTL_Bytes p = table, q;
OTL_UInt num_lookups, offset;
if ( p + 2 > valid->limit )
OTL_INVALID_TOO_SHORT;
num_lookups = OTL_NEXT_USHORT( p );
if ( p + num_lookups * 2 > valid->limit )
OTL_INVALID_TOO_SHORT;
for ( ; num_lookups > 0; num_lookups-- )
{
offset = OTL_NEXT_USHORT( p );
otl_lookup_validate( table + offset, valid );
}
}
OTL_LOCALDEF( OTL_UInt )
otl_lookup_list_get_count( OTL_Bytes table )
{
OTL_Bytes p = table;
return OTL_PEEK_USHORT( p );
}
OTL_LOCALDEF( OTL_Bytes )
otl_lookup_list_get_lookup( OTL_Bytes table,
OTL_UInt idx )
{
OTL_Bytes p, result = 0;
OTL_UInt count;
p = table;
count = OTL_NEXT_USHORT( p );
if ( idx < count )
{
p += idx * 2;
result = table + OTL_PEEK_USHORT( p );
}
return result;
}
OTL_LOCALDEF( OTL_Bytes )
otl_lookup_list_get_table( OTL_Bytes table,
OTL_UInt lookup_index,
OTL_UInt table_index )
{
OTL_Bytes result = NULL;
result = otl_lookup_list_get_lookup( table, lookup_index );
if ( result )
result = otl_lookup_get_table( result, table_index );
return result;
}
OTL_LOCALDEF( void )
otl_lookup_list_foreach( OTL_Bytes table,
OTL_ForeachFunc func,
OTL_Pointer func_data )
{
OTL_Bytes p = table;
OTL_UInt count = OTL_NEXT_USHORT( p );
for ( ; count > 0; count-- )
func( table + OTL_NEXT_USHORT( p ), func_data );
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** FEATURES *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_feature_validate( OTL_Bytes table,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt feat_params, num_lookups;
if ( p + 4 > valid->limit )
OTL_INVALID_TOO_SHORT;
feat_params = OTL_NEXT_USHORT( p ); /* ignored */
num_lookups = OTL_NEXT_USHORT( p );
if ( p + num_lookups * 2 > valid->limit )
OTL_INVALID_TOO_SHORT;
/* XXX: check lookup indices */
}
OTL_LOCALDEF( OTL_UInt )
otl_feature_get_count( OTL_Bytes table )
{
OTL_Bytes p = table + 4;
return OTL_PEEK_USHORT( p );
}
OTL_LOCALDEF( OTL_UInt )
otl_feature_get_lookups( OTL_Bytes table,
OTL_UInt start,
OTL_UInt count,
OTL_UInt *lookups )
{
OTL_Bytes p;
OTL_UInt num_features, result = 0;
p = table + 4;
num_features = OTL_NEXT_USHORT( p );
p += start * 2;
for ( ; count > 0 && start < num_features; count--, start++ )
{
lookups[0] = OTL_NEXT_USHORT(p);
lookups++;
result++;
}
return result;
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** FEATURE LIST *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_feature_list_validate( OTL_Bytes table,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt num_features, offset;
if ( table + 2 > valid->limit )
OTL_INVALID_TOO_SHORT;
num_features = OTL_NEXT_USHORT( p );
if ( p + num_features * 2 > valid->limit )
OTL_INVALID_TOO_SHORT;
for ( ; num_features > 0; num_features-- )
{
p += 4; /* skip tag */
offset = OTL_NEXT_USHORT( p );
otl_feature_table_validate( table + offset, valid );
}
}
OTL_LOCALDEF( OTL_UInt )
otl_feature_list_get_count( OTL_Bytes table )
{
OTL_Bytes p = table;
return OTL_PEEK_USHORT( p );
}
OTL_LOCALDEF( OTL_Bytes )
otl_feature_list_get_feature( OTL_Bytes table,
OTL_UInt idx )
{
OTL_Bytes p, result = NULL;
OTL_UInt count;
p = table;
count = OTL_NEXT_USHORT( p );
if ( idx < count )
{
p += idx * 2;
result = table + OTL_PEEK_USHORT( p );
}
return result;
}
OTL_LOCALDEF( void )
otl_feature_list_foreach( OTL_Bytes table,
OTL_ForeachFunc func,
OTL_Pointer func_data )
{
OTL_Bytes p;
OTL_UInt count;
p = table;
count = OTL_NEXT_USHORT( p );
for ( ; count > 0; count-- )
func( table + OTL_NEXT_USHORT( p ), func_data );
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** LANGUAGE SYSTEM *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_lang_validate( OTL_Bytes table,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt lookup_order;
OTL_UInt req_feature;
OTL_UInt num_features;
if ( table + 6 >= valid->limit )
OTL_INVALID_TOO_SHORT;
lookup_order = OTL_NEXT_USHORT( p );
req_feature = OTL_NEXT_USHORT( p );
num_features = OTL_NEXT_USHORT( p );
/* XXX: check req_feature if not 0xFFFFU */
if ( p + 2 * num_features >= valid->limit )
OTL_INVALID_TOO_SHORT;
/* XXX: check features indices! */
}
OTL_LOCALDEF( OTL_UInt )
otl_lang_get_count( OTL_Bytes table )
{
OTL_Bytes p = table + 4;
return OTL_PEEK_USHORT( p );
}
OTL_LOCALDEF( OTL_UInt )
otl_lang_get_req_feature( OTL_Bytes table )
{
OTL_Bytes p = table + 2;
return OTL_PEEK_USHORT( p );
}
OTL_LOCALDEF( OTL_UInt )
otl_lang_get_features( OTL_Bytes table,
OTL_UInt start,
OTL_UInt count,
OTL_UInt *features )
{
OTL_Bytes p = table + 4;
OTL_UInt num_features = OTL_NEXT_USHORT( p );
OTL_UInt result = 0;
p += start * 2;
for ( ; count > 0 && start < num_features; start++, count-- )
{
features[0] = OTL_NEXT_USHORT( p );
features++;
result++;
}
return result;
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** SCRIPTS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_script_validate( OTL_Bytes table,
OTL_Validator valid )
{
OTL_UInt default_lang;
OTL_Bytes p = table;
if ( table + 4 > valid->limit )
OTL_INVALID_TOO_SHORT;
default_lang = OTL_NEXT_USHORT( p );
num_langs = OTL_NEXT_USHORT( p );
if ( default_lang != 0 )
{
if ( table + default_lang >= valid->limit )
OTL_INVALID_OFFSET;
}
if ( p + num_langs * 6 >= valid->limit )
OTL_INVALID_OFFSET;
for ( ; num_langs > 0; num_langs-- )
{
OTL_UInt offset;
p += 4; /* skip tag */
offset = OTL_NEXT_USHORT( p );
otl_lang_validate( table + offset, valid );
}
}
OTL_LOCALDEF( void )
otl_script_list_validate( OTL_Bytes list,
OTL_Validator valid )
{
OTL_UInt num_scripts;
OTL_Bytes p = list;
if ( list + 2 > valid->limit )
OTL_INVALID_TOO_SHORT;
num_scripts = OTL_NEXT_USHORT( p );
if ( p + num_scripts * 6 > valid->limit )
OTL_INVALID_TOO_SHORT;
for ( ; num_scripts > 0; num_scripts-- )
{
OTL_UInt offset;
p += 4; /* skip tag */
offset = OTL_NEXT_USHORT( p );
otl_script_table_validate( list + offset, valid );
}
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** LOOKUP LISTS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
static void
otl_lookup_table_validate( OTL_Bytes table,
OTL_UInt type_count,
OTL_ValidateFunc* type_funcs,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt lookup_type, lookup_flag, count;
OTL_ValidateFunc validate;
OTL_CHECK( 6 );
lookup_type = OTL_NEXT_USHORT( p );
lookup_flag = OTL_NEXT_USHORT( p );
count = OTL_NEXT_USHORT( p );
if ( lookup_type == 0 || lookup_type >= type_count )
OTL_INVALID_DATA;
validate = type_funcs[ lookup_type - 1 ];
OTL_CHECK( 2*count );
for ( ; count > 0; count-- )
validate( table + OTL_NEXT_USHORT( p ), valid );
}
OTL_LOCALDEF( void )
otl_lookup_list_validate( OTL_Bytes table,
OTL_UInt type_count,
OTL_ValidateFunc* type_funcs,
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_lookup_table_validate( table + OTL_NEXT_USHORT( p ),
type_count, type_funcs, valid );
}
/* END */