mirror of https://github.com/freetype/freetype
[woff2] Read table and collection directory.
* include/freetype/internal/wofftypes.h (WOFF2_TtcFontRec): New structure. (WOFF2_HeaderRec): Add more fields. * src/sfnt/sfwoff2.c (READ_255USHORT, READ_BASE128, ROUND4): New macros. (Read255UShort, CollectionHeaderSize, compute_first_table_offset): New functions. (ReadBase128): Use `FT_READ_BYTE'. (woff2_open_font): Add functionality to read table directory and collection directory (if present).
This commit is contained in:
Nikhil Ramakrishnan
Werner Lemberg
parent
8c1e3fc339
commit
e496cb2980
16
ChangeLog
16
ChangeLog
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@ -1,3 +1,19 @@
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2019-08-27 Nikhil Ramakrishnan <ramakrishnan.nikhil@gmail.com>
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[woff2] Read table and collection directory.
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* include/freetype/internal/wofftypes.h (WOFF2_TtcFontRec): New
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structure.
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(WOFF2_HeaderRec): Add more fields.
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* src/sfnt/sfwoff2.c (READ_255USHORT, READ_BASE128, ROUND4): New
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macros.
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(Read255UShort, CollectionHeaderSize, compute_first_table_offset):
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New functions.
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(ReadBase128): Use `FT_READ_BYTE'.
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(woff2_open_font): Add functionality to read table directory and
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collection directory (if present).
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2019-08-27 Nikhil Ramakrishnan <ramakrishnan.nikhil@gmail.com>
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[sfnt] Include `woff2tags.c' for building.
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@ -104,6 +104,42 @@ FT_BEGIN_HEADER
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} WOFF_TableRec, *WOFF_Table;
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/**************************************************************************
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*
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* @struct:
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* WOFF2_TtcFontRec
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*
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* @description:
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* Metadata for a TTC font entry in WOFF2.
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*
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* @fields:
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* flavor ::
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* TTC font flavor.
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*
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* num_tables ::
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* Number of tables in TTC, indicating number of elements in
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* `table_indices`.
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*
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* dst_offset ::
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* Uncompressed table offset.
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*
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* header_checksum ::
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* Checksum for font header.
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*
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* table_indices ::
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* Array of table indices for each TTC font.
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*/
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typedef struct WOFF2_TtcFontRec_
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{
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FT_ULong flavor;
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FT_UShort num_tables;
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FT_ULong dst_offset;
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FT_ULong header_checksum;
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FT_UShort* table_indices;
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} WOFF2_TtcFontRec, *WOFF2_TtcFont;
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/**************************************************************************
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*
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* @struct:
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@ -123,7 +159,7 @@ FT_BEGIN_HEADER
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* does not necessarily represent the actual size of the uncompressed
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* SFNT font stream, so that is not included either.
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*/
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typedef struct WOFF2_HeaderRec
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typedef struct WOFF2_HeaderRec_
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{
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FT_ULong signature;
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FT_ULong flavor;
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@ -137,7 +173,11 @@ FT_BEGIN_HEADER
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FT_ULong privLength;
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FT_ULong uncompressed_size;
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FT_UInt64 compressed_offset;
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FT_ULong header_version;
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FT_UShort num_fonts;
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WOFF2_TtcFont ttc_fonts;
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} WOFF2_HeaderRec, *WOFF2_Header;
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@ -17,6 +17,7 @@
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#include <ft2build.h>
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#include "sfwoff2.h"
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#include "woff2tags.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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@ -32,6 +33,57 @@
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#define FT_COMPONENT sfwoff2
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#define READ_255USHORT( var ) Read255UShort( stream, &var )
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#define READ_BASE128( var ) ReadBase128( stream, &var )
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#define ROUND4( var ) ( var + 3 ) & ~3
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static FT_Error
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Read255UShort( FT_Stream stream,
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FT_UShort* value )
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{
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static const FT_Int oneMoreByteCode1 = 255;
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static const FT_Int oneMoreByteCode2 = 254;
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static const FT_Int wordCode = 253;
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static const FT_Int lowestUCode = 253;
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FT_Error error;
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FT_Byte code;
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FT_Byte result_byte = 0;
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FT_UShort result_short = 0;
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if( FT_READ_BYTE( code ) )
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return FT_THROW( Invalid_Table );
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if( code == wordCode )
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{
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/* Read next two bytes and store UInt16 value */
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if( FT_READ_USHORT( result_short ) )
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return FT_THROW( Invalid_Table );
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*value = result_short;
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return FT_Err_Ok;
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}
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else if( code == oneMoreByteCode1 )
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{
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if( FT_READ_BYTE( result_byte ) )
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return FT_THROW( Invalid_Table );
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*value = result_byte + lowestUCode;
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return FT_Err_Ok;
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}
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else if( code == oneMoreByteCode2 )
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{
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if( FT_READ_BYTE( result_byte ) )
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return FT_THROW( Invalid_Table );
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*value = result_byte + lowestUCode * 2;
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return FT_Err_Ok;
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}
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else
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{
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*value = code;
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return FT_Err_Ok;
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}
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}
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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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@ -39,11 +91,12 @@
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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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FT_Error error;
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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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if( FT_READ_BYTE( code ) )
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return FT_THROW( Invalid_Table );
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/* Leading zeros are invalid. */
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if ( i == 0 && code == 0x80 ) {
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@ -68,6 +121,41 @@
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}
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static FT_Offset
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CollectionHeaderSize( FT_ULong header_version,
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FT_UShort num_fonts )
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{
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FT_Offset size = 0;
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if (header_version == 0x00020000)
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size += 12; /* ulDsig{Tag,Length,Offset} */
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if (header_version == 0x00010000 || header_version == 0x00020000) {
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size += 12 /* TTCTag, Version, numFonts */
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+ ( 4 * num_fonts ); /* OffsetTable[numFonts] */
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}
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return size;
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}
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static FT_Error
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compute_first_table_offset( const WOFF2_Header woff2 )
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{
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FT_Int nn;
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FT_Offset offset = WOFF2_SFNT_HEADER_SIZE +
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( WOFF2_SFNT_ENTRY_SIZE *
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(FT_Offset)( woff2->num_tables ) );
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if(woff2->header_version)
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{
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offset = CollectionHeaderSize( woff2->header_version,
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woff2->num_fonts )
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+ WOFF2_SFNT_HEADER_SIZE * woff2->num_fonts;
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for ( nn = 0; nn< woff2->num_fonts; nn++ ) {
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offset += WOFF2_SFNT_ENTRY_SIZE * woff2->ttc_fonts[nn].num_tables;
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}
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}
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return offset;
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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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@ -77,12 +165,23 @@
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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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WOFF2_Table last_table;
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FT_Int nn;
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FT_ULong j;
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FT_ULong flags;
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FT_UShort xform_version;
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FT_ULong src_offset = 0;
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FT_UShort ttc_num_tables;
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FT_UInt glyf_index;
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FT_UInt loca_index;
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FT_UInt64 first_table_offset;
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FT_UInt64 file_offset;
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static const FT_Frame_Field woff2_header_fields[] =
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{
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@ -105,14 +204,9 @@
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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_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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@ -122,14 +216,14 @@
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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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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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@ -153,12 +247,205 @@
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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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FT_TRACE2(( "WOFF2 Header is valid.\n" ));
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}
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/* TODO Read table directory. */
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/* Read table directory. */
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if ( FT_NEW_ARRAY( tables, woff2.num_tables ) ||
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FT_NEW_ARRAY( indices, woff2.num_tables ) )
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goto Exit;
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FT_TRACE2(( "\n"
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" tag flags transform origLen transformLen\n"
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" --------------------------------------------------\n" ));
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/* TODO check whether there is sufficient input before FT_READ_*. */
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for ( nn = 0; nn < woff2.num_tables; nn++ )
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{
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WOFF2_Table table = tables + nn;
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if( FT_READ_BYTE( table->FlagByte ) )
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goto Exit;
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if ( ( table->FlagByte & 0x3f ) == 0x3f )
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{
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if( FT_READ_ULONG( table->Tag ) )
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goto Exit;
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}
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else
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table->Tag = KnownTags[table->FlagByte & 0x3f];
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flags = 0;
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xform_version = ( table->FlagByte >> 6 ) & 0x03;
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/* 0 means xform for glyph/loca, non-0 for others. */
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if ( table->Tag == TTAG_glyf || table->Tag == TTAG_loca )
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{
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if ( xform_version == 0 )
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flags |= WOFF2_FLAGS_TRANSFORM;
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}
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else if ( xform_version != 0 )
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flags |= WOFF2_FLAGS_TRANSFORM;
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flags |= xform_version;
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if( READ_BASE128( table->OrigLength ) )
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goto Exit;
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table->TransformLength = table->OrigLength;
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if ( ( flags & WOFF2_FLAGS_TRANSFORM ) != 0 )
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{
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if( READ_BASE128( table->TransformLength ) )
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goto Exit;
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if( table->Tag == TTAG_loca && table->TransformLength )
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{
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FT_ERROR(( "woff_font_open: Invalid loca `transformLength'.\n" ));
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return FT_THROW( Invalid_Table );
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}
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}
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if ( src_offset + table->TransformLength < src_offset )
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{
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FT_ERROR(( "woff_font_open: invalid WOFF2 table directory.\n" ));
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return FT_THROW( Invalid_Table );
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}
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table->src_offset = src_offset;
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table->src_length = table->TransformLength;
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src_offset += table->TransformLength;
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table->flags = flags;
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FT_TRACE2(( " %c%c%c%c %08d %08d %08ld %08ld\n",
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(FT_Char)( table->Tag >> 24 ),
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(FT_Char)( table->Tag >> 16 ),
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(FT_Char)( table->Tag >> 8 ),
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(FT_Char)( table->Tag ),
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table->FlagByte & 0x3f,
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( table->FlagByte >> 6 ) & 0x03,
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table->OrigLength,
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table->TransformLength,
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table->src_length,
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table->src_offset ));
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indices[nn] = table;
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}
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/* End of last table is uncompressed size. */
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last_table = indices[woff2.num_tables - 1];
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woff2.uncompressed_size = last_table->src_offset
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+ last_table->src_length;
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if( woff2.uncompressed_size < last_table->src_offset )
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return FT_THROW( Invalid_Table );
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/* DEBUG - Remove later. */
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FT_TRACE2(( "Uncompressed size: %ld\n", woff2.uncompressed_size ));
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FT_TRACE2(( "Table directory successfully parsed.\n" ));
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/* Check for and read collection directory. */
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woff2.header_version = 0;
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if( woff2.flavor == TTAG_ttcf ){
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FT_TRACE2(( "Font is a TTC, reading collection directory.\n" ));
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if( FT_READ_ULONG( woff2.header_version ) )
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goto Exit;
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/* DEBUG - Remove later */
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FT_TRACE2(( "Header version: %lx\n", woff2.header_version ));
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if( woff2.header_version != 0x00010000 &&
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woff2.header_version != 0x00020000 )
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return FT_THROW( Invalid_Table );
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if( READ_255USHORT( woff2.num_fonts ) )
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goto Exit;
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/* DEBUG - Remove later */
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FT_TRACE2(( "Number of fonts in TTC: %ld\n", woff2.num_fonts ));
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if( FT_NEW_ARRAY( woff2.ttc_fonts, woff2.num_fonts ) )
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goto Exit;
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for ( nn = 0; nn < woff2.num_fonts; nn++ )
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{
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WOFF2_TtcFont ttc_font = woff2.ttc_fonts + nn;
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if( READ_255USHORT( ttc_num_tables ) )
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goto Exit;
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if( FT_READ_ULONG( ttc_font->flavor ) )
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goto Exit;
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if( FT_NEW_ARRAY( ttc_font->table_indices, ttc_num_tables ) )
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goto Exit;
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/* DEBUG - Change to TRACE4 */
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FT_TRACE2(( "Number of tables in font %d: %ld\n",
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nn, ttc_num_tables ));
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/* DEBUG - Change to TRACE5 */
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FT_TRACE2(( " Indices: " ));
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glyf_index = 0;
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loca_index = 0;
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for ( j = 0; j < ttc_num_tables; j++ )
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{
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FT_UShort table_index;
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WOFF2_Table table;
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if( READ_255USHORT( table_index ) )
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goto Exit;
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/* DEBUG - Change to TRACE5 */
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FT_TRACE2(("%hu ", table_index));
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ttc_font->table_indices[j] = table_index;
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|
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table = indices[table_index];
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if( table->Tag == TTAG_loca )
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loca_index = table_index;
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if( table->Tag == TTAG_glyf )
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glyf_index = table_index;
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}
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/* DEBUG - Change to TRACE5 */
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FT_TRACE2(( "\n" ));
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|
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/* glyf and loca must be consecutive */
|
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if( glyf_index > 0 || loca_index > 0 )
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{
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if(glyf_index > loca_index || loca_index - glyf_index != 1)
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return FT_THROW( Invalid_Table );
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/* DEBUG - Remove later */
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else
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FT_TRACE2(( "Glyf and loca are valid.\n" ));
|
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}
|
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}
|
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/* Collection directory reading complete. */
|
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FT_TRACE2(( "WOFF2 collection dirtectory is valid.\n" ));
|
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|
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}
|
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|
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first_table_offset = compute_first_table_offset( &woff2 );
|
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FT_TRACE2(( "Offset to first table: %ld\n", first_table_offset ));
|
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|
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woff2.compressed_offset = FT_STREAM_POS();
|
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file_offset = ROUND4( woff2.compressed_offset +
|
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woff2.totalCompressedSize );
|
||||
|
||||
/* Few more checks before we start reading the tables */
|
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if( file_offset > woff2.length )
|
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return FT_THROW( Invalid_Table );
|
||||
|
||||
if ( woff2.metaOffset )
|
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{
|
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if ( file_offset != woff2.metaOffset )
|
||||
return FT_THROW( Invalid_Table );
|
||||
file_offset = ROUND4(woff2.metaOffset + woff2.metaLength);
|
||||
}
|
||||
|
||||
if( woff2.privOffset )
|
||||
{
|
||||
if( file_offset != woff2.privOffset )
|
||||
return FT_THROW( Invalid_Table );
|
||||
file_offset = ROUND4(woff2.privOffset + woff2.privLength);
|
||||
}
|
||||
|
||||
if( file_offset != ( ROUND4( woff2.length ) ) )
|
||||
return FT_THROW( Invalid_Table );
|
||||
|
||||
error = FT_THROW( Unimplemented_Feature );
|
||||
FT_TRACE2(( "Reached end without errors.\n" ));
|
||||
goto Exit;
|
||||
|
||||
Exit:
|
||||
|
|
|
|||
Loading…
Reference in New Issue