ref: b45c7dd5e2719da00a724bbb29fbc2b882060ade
dir: /src/sfnt/sfwoff2.c/
/****************************************************************************
*
* sfwoff2.c
*
* WOFF2 format management (base).
*
* Copyright (C) 2019 by
* Nikhil Ramakrishnan, 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 <ft2build.h>
#include "sfwoff2.h"
#include FT_TRUETYPE_TAGS_H
#include FT_INTERNAL_DEBUG_H
#include FT_INTERNAL_STREAM_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 sfwoff2
static FT_Error
ReadBase128( FT_Stream stream,
FT_ULong* value )
{
FT_ULong result = 0;
FT_Int i;
FT_Byte code;
FT_Byte* p = stream->cursor;
for ( i = 0; i < 5; ++i ) {
code = 0;
code = FT_NEXT_BYTE( p );
/* Leading zeros are invalid. */
if ( i == 0 && code == 0x80 ) {
return FT_THROW( Invalid_Table );
}
/* If any of top seven bits are set then we're about to overflow. */
if ( result & 0xfe000000 ){
return FT_THROW( Invalid_Table );
}
result = ( result << 7 ) | ( code & 0x7f );
/* Spin until most significant bit of data byte is false. */
if ( (code & 0x80) == 0 ) {
*value = result;
return FT_Err_Ok;
}
}
/* Make sure not to exceed the size bound. */
return FT_THROW( Invalid_Table );
}
/* Replace `face->root.stream' with a stream containing the extracted */
/* SFNT of a WOFF2 font. */
FT_LOCAL_DEF( FT_Error )
woff2_open_font( FT_Stream stream,
TT_Face face )
{
FT_Memory memory = stream->memory;
FT_Error error = FT_Err_Ok;
FT_Byte* p = stream->cursor;
FT_Byte* limit = stream->limit;
WOFF2_HeaderRec woff2;
WOFF2_Table tables = NULL;
WOFF2_Table* indices = NULL;
static const FT_Frame_Field woff2_header_fields[] =
{
#undef FT_STRUCTURE
#define FT_STRUCTURE WOFF2_HeaderRec
FT_FRAME_START( 48 ),
FT_FRAME_ULONG ( signature ),
FT_FRAME_ULONG ( flavor ),
FT_FRAME_ULONG ( length ),
FT_FRAME_USHORT( num_tables ),
FT_FRAME_SKIP_BYTES( 2 + 4 ),
FT_FRAME_ULONG ( totalCompressedSize ),
FT_FRAME_SKIP_BYTES( 2 * 2 ),
FT_FRAME_ULONG ( metaOffset ),
FT_FRAME_ULONG ( metaLength ),
FT_FRAME_ULONG ( metaOrigLength ),
FT_FRAME_ULONG ( privOffset ),
FT_FRAME_ULONG ( privLength ),
FT_FRAME_END
};
FT_UNUSED( p );
FT_UNUSED( limit );
FT_UNUSED( tables );
FT_UNUSED( indices );
FT_UNUSED( memory );
/* DEBUG - Remove later */
FT_TRACE2(("woff2_open_font: Received Data.\n"));
FT_ASSERT( stream == face->root.stream );
FT_ASSERT( FT_STREAM_POS() == 0 );
/* Read WOFF2 Header. */
if ( FT_STREAM_READ_FIELDS( woff2_header_fields, &woff2 ) )
return error;
/* DEBUG - Remove later. */
FT_TRACE2(("signature -> 0x%X\n", woff2.signature));
FT_TRACE2(("flavor -> 0x%X\n", woff2.flavor));
FT_TRACE2(("length -> %lu\n", woff2.length));
FT_TRACE2(("num_tables -> %hu\n", woff2.num_tables));
FT_TRACE2(("metaOffset -> %hu\n", woff2.metaOffset));
FT_TRACE2(("metaLength -> %hu\n", woff2.metaLength));
FT_TRACE2(("privOffset -> %hu\n", woff2.privOffset));
FT_TRACE2(("privLength -> %hu\n", woff2.privLength));
/* Make sure we don't recurse back here. */
if ( woff2.flavor == TTAG_wOF2 )
return FT_THROW( Invalid_Table );
/* Miscellaneous checks. */
if ( woff2.length != stream->size ||
woff2.num_tables == 0 ||
48 + woff2.num_tables * 20UL >= woff2.length ||
( woff2.metaOffset == 0 && ( woff2.metaLength != 0 ||
woff2.metaOrigLength != 0 ) ) ||
( woff2.metaLength != 0 && woff2.metaOrigLength == 0 ) ||
( woff2.metaOffset >= woff2.length ) ||
( woff2.length - woff2.metaOffset < woff2.metaLength ) ||
( woff2.privOffset == 0 && woff2.privLength != 0 ) ||
( woff2.privOffset >= woff2.length ) ||
( woff2.length - woff2.privOffset < woff2.privLength ) )
{
FT_ERROR(( "woff_font_open: invalid WOFF2 header\n" ));
return FT_THROW( Invalid_Table );
}
/* DEBUG - Remove later. */
else{
FT_TRACE2(("WOFF2 Header is valid.\n"));
}
/* TODO Read table directory. */
error = FT_THROW( Unimplemented_Feature );
goto Exit;
Exit:
return error;
}
/* END */