170 lines
5.1 KiB
C
170 lines
5.1 KiB
C
/****************************************************************************
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*
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* sfwoff2.c
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*
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* WOFF2 format management (base).
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*
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* Copyright (C) 2019 by
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* Nikhil Ramakrishnan, David Turner, Robert Wilhelm, and Werner Lemberg.
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*
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* This file is part of the FreeType project, and may only be used,
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* modified, and distributed under the terms of the FreeType project
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* license, LICENSE.TXT. By continuing to use, modify, or distribute
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* this file you indicate that you have read the license and
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* understand and accept it fully.
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*
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*/
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#include <ft2build.h>
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#include "sfwoff2.h"
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#include FT_TRUETYPE_TAGS_H
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#include FT_INTERNAL_DEBUG_H
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#include FT_INTERNAL_STREAM_H
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/**************************************************************************
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*
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* The macro FT_COMPONENT is used in trace mode. It is an implicit
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* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
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* messages during execution.
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*/
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#undef FT_COMPONENT
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#define FT_COMPONENT sfwoff2
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static FT_Error
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ReadBase128( FT_Stream stream,
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FT_ULong* value )
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{
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FT_ULong result = 0;
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FT_Int i;
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FT_Byte code;
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FT_Byte* p = stream->cursor;
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for ( i = 0; i < 5; ++i ) {
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code = 0;
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code = FT_NEXT_BYTE( p );
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/* Leading zeros are invalid. */
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if ( i == 0 && code == 0x80 ) {
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return FT_THROW( Invalid_Table );
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}
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/* If any of top seven bits are set then we're about to overflow. */
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if ( result & 0xfe000000 ){
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return FT_THROW( Invalid_Table );
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}
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result = ( result << 7 ) | ( code & 0x7f );
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/* Spin until most significant bit of data byte is false. */
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if ( (code & 0x80) == 0 ) {
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*value = result;
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return FT_Err_Ok;
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}
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}
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/* Make sure not to exceed the size bound. */
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return FT_THROW( Invalid_Table );
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}
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/* Replace `face->root.stream' with a stream containing the extracted */
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/* SFNT of a WOFF2 font. */
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FT_LOCAL_DEF( FT_Error )
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woff2_open_font( FT_Stream stream,
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TT_Face face )
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{
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FT_Memory memory = stream->memory;
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FT_Error error = FT_Err_Ok;
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FT_Byte* p = stream->cursor;
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FT_Byte* limit = stream->limit;
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WOFF2_HeaderRec woff2;
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WOFF2_Table tables = NULL;
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WOFF2_Table* indices = NULL;
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static const FT_Frame_Field woff2_header_fields[] =
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{
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#undef FT_STRUCTURE
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#define FT_STRUCTURE WOFF2_HeaderRec
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FT_FRAME_START( 48 ),
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FT_FRAME_ULONG ( signature ),
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FT_FRAME_ULONG ( flavor ),
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FT_FRAME_ULONG ( length ),
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FT_FRAME_USHORT( num_tables ),
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FT_FRAME_SKIP_BYTES( 2 + 4 ),
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FT_FRAME_ULONG ( totalCompressedSize ),
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FT_FRAME_SKIP_BYTES( 2 * 2 ),
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FT_FRAME_ULONG ( metaOffset ),
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FT_FRAME_ULONG ( metaLength ),
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FT_FRAME_ULONG ( metaOrigLength ),
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FT_FRAME_ULONG ( privOffset ),
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FT_FRAME_ULONG ( privLength ),
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FT_FRAME_END
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};
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FT_UNUSED( p );
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FT_UNUSED( limit );
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FT_UNUSED( tables );
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FT_UNUSED( indices );
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FT_UNUSED( memory );
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/* DEBUG - Remove later */
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FT_TRACE2(("woff2_open_font: Received Data.\n"));
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FT_ASSERT( stream == face->root.stream );
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FT_ASSERT( FT_STREAM_POS() == 0 );
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/* Read WOFF2 Header. */
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if ( FT_STREAM_READ_FIELDS( woff2_header_fields, &woff2 ) )
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return error;
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/* DEBUG - Remove later. */
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FT_TRACE2(("signature -> 0x%X\n", woff2.signature));
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FT_TRACE2(("flavor -> 0x%X\n", woff2.flavor));
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FT_TRACE2(("length -> %lu\n", woff2.length));
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FT_TRACE2(("num_tables -> %hu\n", woff2.num_tables));
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FT_TRACE2(("metaOffset -> %hu\n", woff2.metaOffset));
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FT_TRACE2(("metaLength -> %hu\n", woff2.metaLength));
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FT_TRACE2(("privOffset -> %hu\n", woff2.privOffset));
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FT_TRACE2(("privLength -> %hu\n", woff2.privLength));
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/* Make sure we don't recurse back here. */
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if ( woff2.flavor == TTAG_wOF2 )
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return FT_THROW( Invalid_Table );
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/* Miscellaneous checks. */
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if ( woff2.length != stream->size ||
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woff2.num_tables == 0 ||
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48 + woff2.num_tables * 20UL >= woff2.length ||
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( woff2.metaOffset == 0 && ( woff2.metaLength != 0 ||
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woff2.metaOrigLength != 0 ) ) ||
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( woff2.metaLength != 0 && woff2.metaOrigLength == 0 ) ||
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( woff2.metaOffset >= woff2.length ) ||
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( woff2.length - woff2.metaOffset < woff2.metaLength ) ||
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( woff2.privOffset == 0 && woff2.privLength != 0 ) ||
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( woff2.privOffset >= woff2.length ) ||
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( woff2.length - woff2.privOffset < woff2.privLength ) )
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{
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FT_ERROR(( "woff_font_open: invalid WOFF2 header\n" ));
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return FT_THROW( Invalid_Table );
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}
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/* DEBUG - Remove later. */
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else{
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FT_TRACE2(("WOFF2 Header is valid.\n"));
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}
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/* TODO Read table directory. */
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error = FT_THROW( Unimplemented_Feature );
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goto Exit;
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Exit:
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return error;
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}
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/* END */
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