[woff2] Check whether known tag is in array bounds.

If table tag is not 0x3f, we expect a value between 0 and 62. If this is
not the case, exit with errors.

* src/sfnt/sfwoff2/c: Check whether table tag makes sense.

* src/sfnt/woff2tags.c: Return 0 if tag is out of bounds.

builds/unix/configure.raw

@@ -543,6 +543,50 @@ if test x"$with_harfbuzz" = xyes -a "$have_harfbuzz" = no; then
 fi
 
 
+# check for system libbrotlidec
+
+AC_ARG_WITH([brotli],
+  [AS_HELP_STRING([--with-brotli=@<:@yes|no|auto@:>@],
+                  [Support decompression of WOFF2 streams @<:@default=auto@:>@])],
+  [], [with_brotli=auto])
+
+have_brotli=no
+if test x"$with_brotli" = xyes -o x"$with_brotli" = xauto; then
+  brotli_pkg="libbrotlidec"
+  have_brotli_pkg=no
+
+  if test x"$BROTLI_CFLAGS" = x -a x"$BROTLI_LIBS" = x; then
+    PKG_CHECK_EXISTS([$brotli_pkg], [have_brotli_pkg=yes])
+  fi
+  PKG_CHECK_MODULES([BROTLI], [$brotli_pkg],
+                    [have_brotli="yes (pkg-config)"], [:])
+
+  if test $have_brotli_pkg = yes; then
+    # we have libbrotlidec.pc
+    brotli_reqpriv="$brotli_pkg"
+    brotli_libspriv=
+    brotli_libsstaticconf=`$PKG_CONFIG --static --libs "$brotli_pkg"`
+  else
+    brotli_reqpriv=
+
+    if test "$have_brotli" != no; then
+      # BROTLI_CFLAGS and BROTLI_LIBS are set by the user
+      brotli_libspriv="$BROTLI_LIBS"
+      brotli_libsstaticconf="$BROTLI_LIBS"
+      have_brotli="yes (BROTLI_CFLAGS and BROTLI_LIBS)"
+    else
+      # since Brotli is quite a new library we don't fall back to a
+      # different test;
+      :
+    fi
+  fi
+fi
+
+if test x"$with_brotli" = xyes -a "$have_brotli" = no; then
+  AC_MSG_ERROR([brotli support requested but library not found])
+fi
+
+
 # check for librt
 #
 # We need `clock_gettime' for the `ftbench' demo program.
@@ -992,7 +1036,8 @@ fi
 REQUIRES_PRIVATE="$zlib_reqpriv,     \
                   $bzip2_reqpriv,    \
                   $libpng_reqpriv,   \
-                  $harfbuzz_reqpriv"
+                  $harfbuzz_reqpriv, \
+                  $brotli_reqpriv"
 # beautify
 REQUIRES_PRIVATE=`echo "$REQUIRES_PRIVATE" \
                   | sed -e 's/^  *//'      \
@@ -1007,6 +1052,7 @@ LIBS_PRIVATE="$zlib_libspriv     \
               $bzip2_libspriv    \
               $libpng_libspriv   \
               $harfbuzz_libspriv \
+              $brotli_libspriv   \
               $ft2_extra_libs"
 # beautify
 LIBS_PRIVATE=`echo "$LIBS_PRIVATE"  \
@@ -1019,6 +1065,7 @@ LIBSSTATIC_CONFIG="-lfreetype               \
                    $bzip2_libsstaticconf    \
                    $libpng_libsstaticconf   \
                    $harfbuzz_libsstaticconf \
+                   $brotli_libsstaticconf   \
                    $ft2_extra_libs"
 # remove -L/usr/lib and -L/usr/lib64 since `freetype-config' adds them later
 # on if necessary; also beautify
@@ -1083,6 +1130,13 @@ if test "$have_harfbuzz" != no; then
 else
   ftoption_unset FT_CONFIG_OPTION_USE_HARFBUZZ
 fi
+if test "$have_brotli" != no; then
+  CFLAGS="$CFLAGS $BROTLI_CFLAGS"
+  LDFLAGS="$LDFLAGS $BROTLI_LIBS"
+  ftoption_set FT_CONFIG_OPTION_USE_BROTLI
+else
+  ftoption_unset FT_CONFIG_OPTION_USE_BROTLI
+fi
 
 AC_SUBST([CFLAGS])
 AC_SUBST([LDFLAGS])
@@ -1129,6 +1183,7 @@ Library configuration:
   bzip2:         $have_bzip2
   libpng:        $have_libpng
   harfbuzz:      $have_harfbuzz
+  brotli:        $have_brotli
 ])
 
 # Warn if docwriter is not installed

devel/ftoption.h

@@ -292,6 +292,22 @@ FT_BEGIN_HEADER
 #define FT_CONFIG_OPTION_USE_HARFBUZZ
 
 
+  /**************************************************************************
+   *
+   * Brotli support.
+   *
+   *   FreeType uses the Brotli library to provide support for decompressing
+   *   WOFF2 streams.
+   *
+   *   Define this macro if you want to enable this 'feature'.
+   *
+   *   If you use a build system like cmake or the `configure` script,
+   *   options set by those programs have precedence, overwriting the value
+   *   here with the configured one.
+   */
+#define FT_CONFIG_OPTION_USE_BROTLI
+
+
   /**************************************************************************
    *
    * Glyph Postscript Names handling

include/freetype/config/ftoption.h

@@ -292,6 +292,22 @@ FT_BEGIN_HEADER
 /* #define FT_CONFIG_OPTION_USE_HARFBUZZ */
 
 
+  /**************************************************************************
+   *
+   * Brotli support.
+   *
+   *   FreeType uses the Brotli library to provide support for decompressing
+   *   WOFF2 streams.
+   *
+   *   Define this macro if you want to enable this 'feature'.
+   *
+   *   If you use a build system like cmake or the `configure` script,
+   *   options set by those programs have precedence, overwriting the value
+   *   here with the configured one.
+   */
+#define FT_CONFIG_OPTION_USE_BROTLI
+
+
   /**************************************************************************
    *
    * Glyph Postscript Names handling

include/freetype/internal/fttrace.h

@@ -49,6 +49,7 @@ FT_TRACE_DEF( cache )     /* cache sub-system        (ftcache.c, etc.) */
 FT_TRACE_DEF( sfdriver )  /* SFNT font driver        (sfdriver.c) */
 FT_TRACE_DEF( sfobjs )    /* SFNT object handler     (sfobjs.c)   */
 FT_TRACE_DEF( sfwoff )    /* WOFF format handler     (sfwoff.c)   */
+FT_TRACE_DEF( sfwoff2 )   /* WOFF2 format handler    (sfwoff2.c)  */
 FT_TRACE_DEF( ttbdf )     /* TrueType embedded BDF   (ttbdf.c)    */
 FT_TRACE_DEF( ttcmap )    /* charmap handler         (ttcmap.c)   */
 FT_TRACE_DEF( ttcolr )    /* glyph layer table       (ttcolr.c)   */

include/freetype/internal/wofftypes.h

@@ -104,6 +104,194 @@ FT_BEGIN_HEADER
   } WOFF_TableRec, *WOFF_Table;
 
 
+  /**************************************************************************
+   *
+   * @struct:
+   *   WOFF2_TtcFontRec
+   *
+   * @description:
+   *   Metadata for a TTC font entry in WOFF2.
+   *
+   * @fields:
+   *   flavor ::
+   *     TTC font flavor.
+   *
+   *   num_tables ::
+   *     Number of tables in TTC, indicating number of elements in
+   *     `table_indices`.
+   *
+   *   table_indices ::
+   *     Array of table indices for each TTC font.
+   */
+  typedef struct  WOFF2_TtcFontRec_
+  {
+    FT_ULong    flavor;
+    FT_UShort   num_tables;
+    FT_UShort*  table_indices;
+
+  } WOFF2_TtcFontRec, *WOFF2_TtcFont;
+
+
+  /**************************************************************************
+   *
+   * @struct:
+   *   WOFF2_HeaderRec
+   *
+   * @description:
+   *   WOFF2 file format header.
+   *
+   * @fields:
+   *   See
+   *
+   *     https://www.w3.org/TR/WOFF2/#woff20Header
+   *
+   * @note:
+   *   We don't care about the fields `reserved`, `majorVersion` and
+   *   `minorVersion`, so they are not included.  The `totalSfntSize` field
+   *   does not necessarily represent the actual size of the uncompressed
+   *   SFNT font stream, so that is used as a reference value instead.
+   */
+  typedef struct  WOFF2_HeaderRec_
+  {
+    FT_ULong   signature;
+    FT_ULong   flavor;
+    FT_ULong   length;
+    FT_UShort  num_tables;
+    FT_ULong   totalSfntSize;
+    FT_ULong   totalCompressedSize;
+    FT_ULong   metaOffset;
+    FT_ULong   metaLength;
+    FT_ULong   metaOrigLength;
+    FT_ULong   privOffset;
+    FT_ULong   privLength;
+
+    FT_ULong   uncompressed_size;    /* uncompressed brotli stream size */
+    FT_ULong   compressed_offset;    /* compressed stream offset        */
+    FT_ULong   header_version;       /* version of original TTC Header  */
+    FT_UShort  num_fonts;            /* number of fonts in TTC          */
+    FT_ULong   actual_sfnt_size;     /* actual size of sfnt stream      */
+
+    WOFF2_TtcFont  ttc_fonts;        /* metadata for fonts in a TTC     */
+
+  } WOFF2_HeaderRec, *WOFF2_Header;
+
+
+  /**************************************************************************
+   *
+   * @struct:
+   *   WOFF2_InfoRec
+   *
+   * @description:
+   *   Metadata for WOFF2 font that may be required for reconstruction of
+   *   sfnt tables.
+   *
+   * @fields:
+   *   header_checksum ::
+   *     Checksum of SFNT offset table.
+   *
+   *   num_glyphs ::
+   *     Number of glyphs in the font.
+   *
+   *   num_hmetrics ::
+   *     `numberOfHMetrics` field in the 'hhea' table.
+   *
+   *   x_mins ::
+   *     `xMin` values of glyph bounding box.
+   */
+  typedef struct  WOFF2_InfoRec_
+  {
+    FT_ULong   header_checksum;
+    FT_UShort  num_glyphs;
+    FT_UShort  num_hmetrics;
+    FT_Short*  x_mins;
+
+  } WOFF2_InfoRec, *WOFF2_Info;
+
+
+  /**************************************************************************
+   *
+   * @struct:
+   *   WOFF2_TableRec
+   *
+   * @description:
+   *   This structure describes a given table of a WOFF2 font.
+   *
+   * @fields:
+   *   See
+   *
+   *     https://www.w3.org/TR/WOFF2/#table_dir_format
+   */
+  typedef struct  WOFF2_TableRec_
+  {
+    FT_Byte   FlagByte;           /* table type and flags      */
+    FT_ULong  Tag;                /* table file offset         */
+    FT_ULong  dst_length;         /* uncompressed table length */
+    FT_ULong  TransformLength;    /* transformed length        */
+
+    FT_ULong  flags;              /* calculated flags          */
+    FT_ULong  src_offset;         /* compressed table offset   */
+    FT_ULong  src_length;         /* compressed table length   */
+    FT_ULong  dst_offset;         /* uncompressed table offset */
+
+  } WOFF2_TableRec, *WOFF2_Table;
+
+
+  /**************************************************************************
+   *
+   * @struct:
+   *   WOFF2_SubstreamRec
+   *
+   * @description:
+   *   This structure stores information about a substream in the transformed
+   *   'glyf' table in a WOFF2 stream.
+   *
+   * @fields:
+   *   start ::
+   *     Beginning of the substream relative to uncompressed table stream.
+   *
+   *   offset ::
+   *     Offset of the substream relative to uncompressed table stream.
+   *
+   *   size ::
+   *     Size of the substream.
+   */
+  typedef struct  WOFF2_SubstreamRec_
+  {
+    FT_ULong  start;
+    FT_ULong  offset;
+    FT_ULong  size;
+
+  } WOFF2_SubstreamRec, *WOFF2_Substream;
+
+
+  /**************************************************************************
+   *
+   * @struct:
+   *   WOFF2_PointRec
+   *
+   * @description:
+   *   This structure stores information about a point in the transformed
+   *   'glyf' table in a WOFF2 stream.
+   *
+   * @fields:
+   *   x ::
+   *     x-coordinate.
+   *
+   *   y ::
+   *     y-coordinate.
+   *
+   *   on_curve ::
+   *     Whether point is on-curve.
+   */
+  typedef struct  WOFF2_PointRec_
+  {
+    FT_Int   x;
+    FT_Int   y;
+    FT_Bool  on_curve;
+
+  } WOFF2_PointRec, *WOFF2_Point;
+
+
 FT_END_HEADER
 
 #endif /* WOFFTYPES_H_ */

include/freetype/tttags.h

@@ -107,6 +107,7 @@ FT_BEGIN_HEADER
 #define TTAG_vmtx  FT_MAKE_TAG( 'v', 'm', 't', 'x' )
 #define TTAG_VVAR  FT_MAKE_TAG( 'V', 'V', 'A', 'R' )
 #define TTAG_wOFF  FT_MAKE_TAG( 'w', 'O', 'F', 'F' )
+#define TTAG_wOF2  FT_MAKE_TAG( 'w', 'O', 'F', '2' )
 
 /* used by "Keyboard.dfont" on legacy Mac OS X */
 #define TTAG_0xA5kbd  FT_MAKE_TAG( 0xA5, 'k', 'b', 'd' )

src/sfnt/rules.mk

@@ -32,6 +32,7 @@ SFNT_DRV_SRC := $(SFNT_DIR)/pngshim.c  \
                 $(SFNT_DIR)/sfdriver.c \
                 $(SFNT_DIR)/sfobjs.c   \
                 $(SFNT_DIR)/sfwoff.c   \
+                $(SFNT_DIR)/sfwoff2.c  \
                 $(SFNT_DIR)/ttbdf.c    \
                 $(SFNT_DIR)/ttcmap.c   \
                 $(SFNT_DIR)/ttcolr.c   \
@@ -40,7 +41,8 @@ SFNT_DRV_SRC := $(SFNT_DIR)/pngshim.c  \
                 $(SFNT_DIR)/ttload.c   \
                 $(SFNT_DIR)/ttmtx.c    \
                 $(SFNT_DIR)/ttpost.c   \
-                $(SFNT_DIR)/ttsbit.c
+                $(SFNT_DIR)/ttsbit.c   \
+                $(SFNT_DIR)/woff2tags.c
 
 # SFNT driver headers
 #

src/sfnt/sfnt.c

@@ -23,6 +23,7 @@
 #include "sfdriver.c"
 #include "sfobjs.c"
 #include "sfwoff.c"
+#include "sfwoff2.c"
 #include "ttbdf.c"
 #include "ttcmap.c"
 #include "ttcolr.c"
@@ -33,6 +34,7 @@
 #include "ttmtx.c"
 #include "ttpost.c"
 #include "ttsbit.c"
+#include "woff2tags.c"
 
 
 /* END */

src/sfnt/sfobjs.c

@@ -22,6 +22,7 @@
 #include "ttcmap.h"
 #include "ttkern.h"
 #include "sfwoff.h"
+#include "sfwoff2.h"
 #include FT_INTERNAL_SFNT_H
 #include FT_INTERNAL_DEBUG_H
 #include FT_TRUETYPE_IDS_H
@@ -341,7 +342,9 @@
   /* synthesized into a TTC with one offset table.              */
   static FT_Error
   sfnt_open_font( FT_Stream  stream,
-                  TT_Face    face )
+                  TT_Face    face,
+                  FT_Int*    face_instance_index,
+                  FT_Long*   woff2_num_faces )
   {
     FT_Memory  memory = stream->memory;
     FT_Error   error;
@@ -385,6 +388,25 @@
       goto retry;
     }
 
+    if ( tag == TTAG_wOF2 )
+    {
+      FT_TRACE2(( "sfnt_open_font: file is a WOFF2; synthesizing SFNT\n" ));
+
+      if ( FT_STREAM_SEEK( offset ) )
+        return error;
+
+      error = woff2_open_font( stream,
+                               face,
+                               face_instance_index,
+                               woff2_num_faces );
+      if ( error )
+        return error;
+
+      /* Swap out stream and retry! */
+      stream = face->root.stream;
+      goto retry;
+    }
+
     if ( tag != 0x00010000UL &&
          tag != TTAG_ttcf    &&
          tag != TTAG_OTTO    &&
@@ -461,9 +483,10 @@
                   FT_Parameter*  params )
   {
     FT_Error      error;
-    FT_Library    library = face->root.driver->root.library;
+    FT_Library    library         = face->root.driver->root.library;
     SFNT_Service  sfnt;
     FT_Int        face_index;
+    FT_Long       woff2_num_faces = 0;
 
 
     /* for now, parameters are unused */
@@ -514,7 +537,10 @@
 
     FT_TRACE2(( "SFNT driver\n" ));
 
-    error = sfnt_open_font( stream, face );
+    error = sfnt_open_font( stream,
+                            face,
+                            &face_instance_index,
+                            &woff2_num_faces );
     if ( error )
       return error;
 
@@ -689,6 +715,10 @@
     face->root.num_faces  = face->ttc_header.count;
     face->root.face_index = face_instance_index;
 
+    /* `num_faces' for a WOFF2 needs to be handled separately. */
+    if ( woff2_num_faces )
+      face->root.num_faces = woff2_num_faces;
+
     return error;
   }
 

src/sfnt/sfwoff2.h

@@ -0,0 +1,76 @@
+/****************************************************************************
+ *
+ * sfwoff2.h
+ *
+ *   WOFFF2 format management (specification).
+ *
+ * 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.
+ *
+ */
+
+
+#ifndef SFWOFF2_H_
+#define SFWOFF2_H_
+
+
+#include <ft2build.h>
+#include FT_INTERNAL_SFNT_H
+#include FT_INTERNAL_OBJECTS_H
+
+
+FT_BEGIN_HEADER
+
+
+  /* Leave the first byte open to store flag_byte. */
+#define WOFF2_FLAGS_TRANSFORM   1 << 8
+
+#define WOFF2_SFNT_HEADER_SIZE  12
+#define WOFF2_SFNT_ENTRY_SIZE   16
+
+  /* Suggested max size for output. */
+#define WOFF2_DEFAULT_MAX_SIZE  30 * 1024 * 1024
+
+  /* 98% of Google Fonts have no glyph above 5k bytes. */
+#define WOFF2_DEFAULT_GLYPH_BUF  5120
+
+  /* Composite glyph flags                                     */
+  /* See CompositeGlyph.java in `sfntly' for full definitions  */
+#define FLAG_ARG_1_AND_2_ARE_WORDS     1 << 0
+#define FLAG_WE_HAVE_A_SCALE           1 << 3
+#define FLAG_MORE_COMPONENTS           1 << 5
+#define FLAG_WE_HAVE_AN_X_AND_Y_SCALE  1 << 6
+#define FLAG_WE_HAVE_A_TWO_BY_TWO      1 << 7
+#define FLAG_WE_HAVE_INSTRUCTIONS      1 << 8
+
+  /* Simple glyph flags */
+#define GLYF_ON_CURVE        1 << 0
+#define GLYF_X_SHORT         1 << 1
+#define GLYF_Y_SHORT         1 << 2
+#define GLYF_REPEAT          1 << 3
+#define GLYF_THIS_X_IS_SAME  1 << 4
+#define GLYF_THIS_Y_IS_SAME  1 << 5
+
+  /* Other constants */
+#define CONTOUR_OFFSET_END_POINT  10
+
+
+  FT_LOCAL( FT_Error )
+  woff2_open_font( FT_Stream  stream,
+                   TT_Face    face,
+                   FT_Int*    face_index,
+                   FT_Long*   num_faces );
+
+
+FT_END_HEADER
+
+#endif /* SFWOFF2_H_ */
+
+
+/* END */

src/sfnt/woff2tags.c

@@ -0,0 +1,101 @@
+/****************************************************************************
+ *
+ * woff2tags.c
+ *
+ *   WOFF2 Font table tags (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 "sfwoff.h"
+#include FT_TRUETYPE_TAGS_H
+
+  /* Return tag from index in the order given in WOFF2 specification. */
+  FT_LOCAL_DEF( FT_ULong )
+  woff2_known_tags( FT_Byte  index )
+  {
+    const FT_ULong  known_tags[63] =
+    {
+      FT_MAKE_TAG('c', 'm', 'a', 'p'),  /*  0  */
+      FT_MAKE_TAG('h', 'e', 'a', 'd'),  /*  1  */
+      FT_MAKE_TAG('h', 'h', 'e', 'a'),  /*  2  */
+      FT_MAKE_TAG('h', 'm', 't', 'x'),  /*  3  */
+      FT_MAKE_TAG('m', 'a', 'x', 'p'),  /*  4  */
+      FT_MAKE_TAG('n', 'a', 'm', 'e'),  /*  5  */
+      FT_MAKE_TAG('O', 'S', '/', '2'),  /*  6  */
+      FT_MAKE_TAG('p', 'o', 's', 't'),  /*  7  */
+      FT_MAKE_TAG('c', 'v', 't', ' '),  /*  8  */
+      FT_MAKE_TAG('f', 'p', 'g', 'm'),  /*  9  */
+      FT_MAKE_TAG('g', 'l', 'y', 'f'),  /*  10 */
+      FT_MAKE_TAG('l', 'o', 'c', 'a'),  /*  11 */
+      FT_MAKE_TAG('p', 'r', 'e', 'p'),  /*  12 */
+      FT_MAKE_TAG('C', 'F', 'F', ' '),  /*  13 */
+      FT_MAKE_TAG('V', 'O', 'R', 'G'),  /*  14 */
+      FT_MAKE_TAG('E', 'B', 'D', 'T'),  /*  15 */
+      FT_MAKE_TAG('E', 'B', 'L', 'C'),  /*  16 */
+      FT_MAKE_TAG('g', 'a', 's', 'p'),  /*  17 */
+      FT_MAKE_TAG('h', 'd', 'm', 'x'),  /*  18 */
+      FT_MAKE_TAG('k', 'e', 'r', 'n'),  /*  19 */
+      FT_MAKE_TAG('L', 'T', 'S', 'H'),  /*  20 */
+      FT_MAKE_TAG('P', 'C', 'L', 'T'),  /*  21 */
+      FT_MAKE_TAG('V', 'D', 'M', 'X'),  /*  22 */
+      FT_MAKE_TAG('v', 'h', 'e', 'a'),  /*  23 */
+      FT_MAKE_TAG('v', 'm', 't', 'x'),  /*  24 */
+      FT_MAKE_TAG('B', 'A', 'S', 'E'),  /*  25 */
+      FT_MAKE_TAG('G', 'D', 'E', 'F'),  /*  26 */
+      FT_MAKE_TAG('G', 'P', 'O', 'S'),  /*  27 */
+      FT_MAKE_TAG('G', 'S', 'U', 'B'),  /*  28 */
+      FT_MAKE_TAG('E', 'B', 'S', 'C'),  /*  29 */
+      FT_MAKE_TAG('J', 'S', 'T', 'F'),  /*  30 */
+      FT_MAKE_TAG('M', 'A', 'T', 'H'),  /*  31 */
+      FT_MAKE_TAG('C', 'B', 'D', 'T'),  /*  32 */
+      FT_MAKE_TAG('C', 'B', 'L', 'C'),  /*  33 */
+      FT_MAKE_TAG('C', 'O', 'L', 'R'),  /*  34 */
+      FT_MAKE_TAG('C', 'P', 'A', 'L'),  /*  35 */
+      FT_MAKE_TAG('S', 'V', 'G', ' '),  /*  36 */
+      FT_MAKE_TAG('s', 'b', 'i', 'x'),  /*  37 */
+      FT_MAKE_TAG('a', 'c', 'n', 't'),  /*  38 */
+      FT_MAKE_TAG('a', 'v', 'a', 'r'),  /*  39 */
+      FT_MAKE_TAG('b', 'd', 'a', 't'),  /*  40 */
+      FT_MAKE_TAG('b', 'l', 'o', 'c'),  /*  41 */
+      FT_MAKE_TAG('b', 's', 'l', 'n'),  /*  42 */
+      FT_MAKE_TAG('c', 'v', 'a', 'r'),  /*  43 */
+      FT_MAKE_TAG('f', 'd', 's', 'c'),  /*  44 */
+      FT_MAKE_TAG('f', 'e', 'a', 't'),  /*  45 */
+      FT_MAKE_TAG('f', 'm', 't', 'x'),  /*  46 */
+      FT_MAKE_TAG('f', 'v', 'a', 'r'),  /*  47 */
+      FT_MAKE_TAG('g', 'v', 'a', 'r'),  /*  48 */
+      FT_MAKE_TAG('h', 's', 't', 'y'),  /*  49 */
+      FT_MAKE_TAG('j', 'u', 's', 't'),  /*  50 */
+      FT_MAKE_TAG('l', 'c', 'a', 'r'),  /*  51 */
+      FT_MAKE_TAG('m', 'o', 'r', 't'),  /*  52 */
+      FT_MAKE_TAG('m', 'o', 'r', 'x'),  /*  53 */
+      FT_MAKE_TAG('o', 'p', 'b', 'd'),  /*  54 */
+      FT_MAKE_TAG('p', 'r', 'o', 'p'),  /*  55 */
+      FT_MAKE_TAG('t', 'r', 'a', 'k'),  /*  56 */
+      FT_MAKE_TAG('Z', 'a', 'p', 'f'),  /*  57 */
+      FT_MAKE_TAG('S', 'i', 'l', 'f'),  /*  58 */
+      FT_MAKE_TAG('G', 'l', 'a', 't'),  /*  59 */
+      FT_MAKE_TAG('G', 'l', 'o', 'c'),  /*  60 */
+      FT_MAKE_TAG('F', 'e', 'a', 't'),  /*  61 */
+      FT_MAKE_TAG('S', 'i', 'l', 'l'),  /*  62 */
+    };
+
+
+    if ( index < 0 || index > 62 )
+      return 0;
+
+    return known_tags[index];
+  }
+
+
+/* END */

src/sfnt/woff2tags.h

@@ -0,0 +1,39 @@
+/****************************************************************************
+ *
+ * woff2tags.h
+ *
+ *   WOFFF2 Font table tags (specification).
+ *
+ * Copyright (C) 1996-2019 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.
+ *
+ */
+
+
+#ifndef WOFF2TAGS_H
+#define WOFF2TAGS_H
+
+
+#include <ft2build.h>
+#include FT_INTERNAL_OBJECTS_H
+
+
+FT_BEGIN_HEADER
+
+
+  FT_LOCAL( FT_ULong )
+  woff2_known_tags( FT_Byte  index );
+
+
+FT_END_HEADER
+
+#endif /* WOFF2TAGS_H */
+
+
+/* END */