ref: 8285d49a70e2e6e1bc011416cf07ae3301f75a25
dir: /src/otlayout/otlcommn.c/
/***************************************************************************/
/* */
/* otlcommn.c */
/* */
/* OpenType layout support, common tables (body). */
/* */
/* Copyright 2002, 2004 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 = table;
OTL_UInt format;
OTL_CHECK( 4 );
format = OTL_NEXT_USHORT( p );
switch ( format )
{
case 1:
{
OTL_UInt num_glyphs = OTL_NEXT_USHORT( p );
OTL_CHECK( num_glyphs * 2 );
}
break;
case 2:
{
OTL_UInt n, num_ranges = OTL_NEXT_USHORT( p );
OTL_UInt start, end, start_coverage, total = 0, last = 0;
OTL_CHECK( num_ranges * 6 );
/* scan range records */
for ( n = 0; n < num_ranges; n++ )
{
start = OTL_NEXT_USHORT( p );
end = OTL_NEXT_USHORT( p );
start_coverage = OTL_NEXT_USHORT( p );
if ( start > end || start_coverage != total )
OTL_INVALID_DATA;
if ( n > 0 && start <= last )
OTL_INVALID_DATA;
total += end - start + 1;
last = end;
}
}
break;
default:
OTL_INVALID_FORMAT;
}
/* no need to check glyph indices used as input to coverage tables */
/* since even invalid glyph indices return a meaningful result */
}
OTL_LOCALDEF( OTL_UInt )
otl_coverage_get_first( OTL_Bytes table )
{
OTL_Bytes p = table;
p += 4; /* skip format and count */
return OTL_NEXT_USHORT( p );
}
OTL_LOCALDEF( OTL_UInt )
otl_coverage_get_last( OTL_Bytes table )
{
OTL_Bytes p = table;
OTL_UInt format = OTL_NEXT_USHORT( p );
OTL_UInt count = OTL_NEXT_USHORT( p );
OTL_UInt result;
switch ( format )
{
case 1:
p += ( count - 1 ) * 2;
result = OTL_NEXT_USHORT( p );
break;
case 2:
p += ( count - 1 ) * 6 + 2;
result = OTL_NEXT_USHORT( p );
break;
default:
;
}
return result;
}
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;
}
#if 0
OTL_LOCALDEF( OTL_Long )
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_Long)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;
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_Long)( glyph_index + OTL_NEXT_USHORT( p ) - start );
}
}
break;
default:
;
}
return -1;
}
#endif
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** CLASS DEFINITION TABLE *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_class_definition_validate( OTL_Bytes table,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt format;
OTL_CHECK( 4 );
format = OTL_NEXT_USHORT( p );
switch ( format )
{
case 1:
{
OTL_UInt num_glyphs;
p += 2; /* skip start_glyph */
OTL_CHECK( 2 );
num_glyphs = OTL_NEXT_USHORT( p );
OTL_CHECK( num_glyphs * 2 );
}
break;
case 2:
{
OTL_UInt n, num_ranges = OTL_NEXT_USHORT( p );
OTL_UInt start, end, last = 0;
OTL_CHECK( num_ranges * 6 );
/* scan class range records */
for ( n = 0; n < num_ranges; n++ )
{
start = OTL_NEXT_USHORT( p );
end = OTL_NEXT_USHORT( p );
p += 2; /* ignored */
if ( start > end || ( n > 0 && start <= last ) )
OTL_INVALID_DATA;
last = end;
}
}
break;
default:
OTL_INVALID_FORMAT;
}
/* no need to check glyph indices used as input to class definition */
/* tables since even invalid glyph indices return a meaningful result */
}
#if 0
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, start, end;
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;
}
#endif
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** 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;
OTL_CHECK( 8 );
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 = end - start + 1;
OTL_CHECK( ( 1 << format ) * count / 8 );
}
#if 0
OTL_LOCALDEF( OTL_UInt )
otl_device_table_get_start( OTL_Bytes table )
{
OTL_Bytes p = table;
return OTL_PEEK_USHORT( p );
}
#endif
#if 0
OTL_LOCALDEF( OTL_UInt )
otl_device_table_get_end( OTL_Bytes table )
{
OTL_Bytes p = table + 2;
return OTL_PEEK_USHORT( p );
}
#endif
#if 0
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, shift;
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_Int16)( 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_Int16)( 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_Int16)( value << shift ) >> ( 8 - shift );
break;
default:
;
}
}
return result;
}
#endif
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** LOOKUPS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_lookup_validate( OTL_Bytes table,
OTL_UInt type_count,
OTL_ValidateFunc* type_funcs,
OTL_UInt lookup_count,
OTL_UInt glyph_count,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt lookup_type, lookup_flag, num_subtables;
OTL_ValidateFunc validate;
OTL_CHECK( 6 );
lookup_type = OTL_NEXT_USHORT( p );
lookup_flag = OTL_NEXT_USHORT( p );
num_subtables = OTL_NEXT_USHORT( p );
if ( lookup_type == 0 || lookup_type >= type_count )
OTL_INVALID_DATA;
validate = type_funcs[lookup_type - 1];
OTL_CHECK( 2 * num_subtables );
/* scan subtables */
for ( ; num_subtables > 0; num_subtables-- )
validate( table + OTL_NEXT_USHORT( p ), lookup_count, glyph_count,
valid );
}
#if 0
OTL_LOCALDEF( OTL_UInt )
otl_lookup_get_count( OTL_Bytes table )
{
OTL_Bytes p = table + 4;
return OTL_PEEK_USHORT( p );
}
#endif
#if 0
OTL_LOCALDEF( OTL_Bytes )
otl_lookup_get_table( OTL_Bytes table,
OTL_UInt idx )
{
OTL_Bytes p, result = 0;
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;
}
#endif
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** LOOKUP LISTS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_lookup_list_validate( OTL_Bytes table,
OTL_UInt type_count,
OTL_ValidateFunc* type_funcs,
OTL_UInt glyph_count,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt num_lookups, count;
OTL_CHECK( 2 );
num_lookups = OTL_NEXT_USHORT( p );
OTL_CHECK( 2 * num_lookups );
/* scan lookup records */
for ( count = num_lookups; count > 0; count-- )
otl_lookup_validate( table + OTL_NEXT_USHORT( p ),
type_count, type_funcs,
num_lookups, glyph_count, valid );
}
OTL_LOCALDEF( OTL_UInt )
otl_lookup_list_get_count( OTL_Bytes table )
{
OTL_Bytes p = table;
return OTL_PEEK_USHORT( p );
}
#if 0
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;
}
#endif
#if 0
OTL_LOCALDEF( OTL_Bytes )
otl_lookup_list_get_table( OTL_Bytes table,
OTL_UInt lookup_index,
OTL_UInt table_index )
{
OTL_Bytes result = 0;
result = otl_lookup_list_get_lookup( table, lookup_index );
if ( result )
result = otl_lookup_get_table( result, table_index );
return result;
}
#endif
#if 0
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 );
}
#endif
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** FEATURES *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_feature_validate( OTL_Bytes table,
OTL_UInt lookup_count,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt num_lookups;
OTL_CHECK( 4 );
p += 2; /* unused */
num_lookups = OTL_NEXT_USHORT( p );
OTL_CHECK( 2 * num_lookups );
for ( ; num_lookups > 0; num_lookups-- )
if ( OTL_NEXT_USHORT( p ) >= lookup_count )
OTL_INVALID_DATA;
}
#if 0
OTL_LOCALDEF( OTL_UInt )
otl_feature_get_count( OTL_Bytes table )
{
OTL_Bytes p = table + 4;
return OTL_PEEK_USHORT( p );
}
#endif
#if 0
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;
}
#endif
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** FEATURE LIST *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_feature_list_validate( OTL_Bytes table,
OTL_Bytes lookups,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt num_features, lookup_count;
OTL_CHECK( 2 );
num_features = OTL_NEXT_USHORT( p );
OTL_CHECK( 2 * num_features );
lookup_count = otl_lookup_list_get_count( lookups );
/* scan feature records */
for ( ; num_features > 0; num_features-- )
{
p += 4; /* skip tag */
otl_feature_validate( table + OTL_NEXT_USHORT( p ), lookup_count,
valid );
}
}
OTL_LOCALDEF( OTL_UInt )
otl_feature_list_get_count( OTL_Bytes table )
{
OTL_Bytes p = table;
return OTL_PEEK_USHORT( p );
}
#if 0
OTL_LOCALDEF( OTL_Bytes )
otl_feature_list_get_feature( 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;
}
#endif
#if 0
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 );
}
#endif
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** LANGUAGE SYSTEM *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_lang_validate( OTL_Bytes table,
OTL_UInt feature_count,
OTL_Validator valid )
{
OTL_Bytes p = table;
OTL_UInt req_feature;
OTL_UInt num_features;
OTL_CHECK( 6 );
p += 2; /* unused */
req_feature = OTL_NEXT_USHORT( p );
num_features = OTL_NEXT_USHORT( p );
if ( req_feature != 0xFFFFU && req_feature >= feature_count )
OTL_INVALID_DATA;
OTL_CHECK( 2 * num_features );
for ( ; num_features > 0; num_features-- )
if ( OTL_NEXT_USHORT( p ) >= feature_count )
OTL_INVALID_DATA;
}
#if 0
OTL_LOCALDEF( OTL_UInt )
otl_lang_get_count( OTL_Bytes table )
{
OTL_Bytes p = table + 4;
return OTL_PEEK_USHORT( p );
}
#endif
#if 0
OTL_LOCALDEF( OTL_UInt )
otl_lang_get_req_feature( OTL_Bytes table )
{
OTL_Bytes p = table + 2;
return OTL_PEEK_USHORT( p );
}
#endif
#if 0
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;
}
#endif
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** SCRIPTS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( void )
otl_script_validate( OTL_Bytes table,
OTL_UInt feature_count,
OTL_Validator valid )
{
OTL_UInt default_lang, num_langs;
OTL_Bytes p = table;
OTL_CHECK( 4 );
default_lang = OTL_NEXT_USHORT( p );
num_langs = OTL_NEXT_USHORT( p );
if ( default_lang != 0 )
otl_lang_validate( table + default_lang, feature_count, valid );
OTL_CHECK( num_langs * 6 );
/* scan langsys records */
for ( ; num_langs > 0; num_langs-- )
{
p += 4; /* skip tag */
otl_lang_validate( table + OTL_NEXT_USHORT( p ), feature_count, valid );
}
}
OTL_LOCALDEF( void )
otl_script_list_validate( OTL_Bytes table,
OTL_Bytes features,
OTL_Validator valid )
{
OTL_UInt num_scripts, feature_count;
OTL_Bytes p = table;
OTL_CHECK( 2 );
num_scripts = OTL_NEXT_USHORT( p );
OTL_CHECK( num_scripts * 6 );
feature_count = otl_feature_list_get_count( features );
/* scan script records */
for ( ; num_scripts > 0; num_scripts-- )
{
p += 4; /* skip tag */
otl_script_validate( table + OTL_NEXT_USHORT( p ), feature_count,
valid );
}
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** UTILITY FUNCTIONS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
OTL_LOCALDEF( OTL_UInt )
otl_gsubgpos_get_lookup_count( OTL_Bytes table )
{
OTL_Bytes p = table + 8;
return otl_lookup_list_get_count( table + OTL_PEEK_USHORT( p ) );
}
/* END */