kc3-lang/freetype/src/sfnt/ttload.c

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• Hash : 08268691
  Author :
  Date : 2023-04-28T15:32:16
  

  * src/sfnt/ttload.c (tt_face_load_font_dir): Add another guard. Reject 'OTTO' fonts with no valid tables.

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• src/sfnt/ttload.c

• /****************************************************************************
   *
   * ttload.c
   *
   *   Load the basic TrueType tables, i.e., tables that can be either in
   *   TTF or OTF fonts (body).
   *
   * Copyright (C) 1996-2023 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 <freetype/internal/ftdebug.h>
  #include <freetype/internal/ftstream.h>
  #include <freetype/tttags.h>
  #include "ttload.h"
  
  #include "sferrors.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  ttload
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_lookup_table
     *
     * @Description:
     *   Looks for a TrueType table by name.
     *
     * @Input:
     *   face ::
     *     A face object handle.
     *
     *   tag ::
     *     The searched tag.
     *
     * @Return:
     *   A pointer to the table directory entry.  0 if not found.
     */
    FT_LOCAL_DEF( TT_Table  )
    tt_face_lookup_table( TT_Face   face,
                          FT_ULong  tag  )
    {
      TT_Table  entry;
      TT_Table  limit;
  #ifdef FT_DEBUG_LEVEL_TRACE
      FT_Bool   zero_length = FALSE;
  #endif
  
  
      FT_TRACE4(( "tt_face_lookup_table: %p, `%c%c%c%c' -- ",
                  (void *)face,
                  (FT_Char)( tag >> 24 ),
                  (FT_Char)( tag >> 16 ),
                  (FT_Char)( tag >> 8  ),
                  (FT_Char)( tag       ) ));
  
      entry = face->dir_tables;
      limit = entry + face->num_tables;
  
      for ( ; entry < limit; entry++ )
      {
        /* For compatibility with Windows, we consider    */
        /* zero-length tables the same as missing tables. */
        if ( entry->Tag == tag )
        {
          if ( entry->Length != 0 )
          {
            FT_TRACE4(( "found table.\n" ));
            return entry;
          }
  #ifdef FT_DEBUG_LEVEL_TRACE
          zero_length = TRUE;
  #endif
        }
      }
  
  #ifdef FT_DEBUG_LEVEL_TRACE
      if ( zero_length )
        FT_TRACE4(( "ignoring empty table\n" ));
      else
        FT_TRACE4(( "could not find table\n" ));
  #endif
  
      return NULL;
    }
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_goto_table
     *
     * @Description:
     *   Looks for a TrueType table by name, then seek a stream to it.
     *
     * @Input:
     *   face ::
     *     A face object handle.
     *
     *   tag ::
     *     The searched tag.
     *
     *   stream ::
     *     The stream to seek when the table is found.
     *
     * @Output:
     *   length ::
     *     The length of the table if found, undefined otherwise.
     *
     * @Return:
     *   FreeType error code.  0 means success.
     */
    FT_LOCAL_DEF( FT_Error )
    tt_face_goto_table( TT_Face    face,
                        FT_ULong   tag,
                        FT_Stream  stream,
                        FT_ULong*  length )
    {
      TT_Table  table;
      FT_Error  error;
  
  
      table = tt_face_lookup_table( face, tag );
      if ( table )
      {
        if ( length )
          *length = table->Length;
  
        if ( FT_STREAM_SEEK( table->Offset ) )
          goto Exit;
      }
      else
        error = FT_THROW( Table_Missing );
  
    Exit:
      return error;
    }
  
  
    /* Here, we                                                         */
    /*                                                                  */
    /* - check that `num_tables' is valid (and adjust it if necessary); */
    /*   also return the number of valid table entries                  */
    /*                                                                  */
    /* - look for a `head' table, check its size, and parse it to check */
    /*   whether its `magic' field is correctly set                     */
    /*                                                                  */
    /* - errors (except errors returned by stream handling)             */
    /*                                                                  */
    /*     SFNT_Err_Unknown_File_Format:                                */
    /*       no table is defined in directory, it is not sfnt-wrapped   */
    /*       data                                                       */
    /*     SFNT_Err_Table_Missing:                                      */
    /*       table directory is valid, but essential tables             */
    /*       (head/bhed/SING) are missing                               */
    /*                                                                  */
    static FT_Error
    check_table_dir( SFNT_Header  sfnt,
                     FT_Stream    stream,
                     FT_UShort*   valid )
    {
      FT_Error   error;
      FT_UShort  nn, valid_entries = 0;
      FT_UInt    has_head = 0, has_sing = 0, has_meta = 0;
      FT_ULong   offset = sfnt->offset + 12;
  
      static const FT_Frame_Field  table_dir_entry_fields[] =
      {
  #undef  FT_STRUCTURE
  #define FT_STRUCTURE  TT_TableRec
  
        FT_FRAME_START( 16 ),
          FT_FRAME_ULONG( Tag ),
          FT_FRAME_ULONG( CheckSum ),
          FT_FRAME_ULONG( Offset ),
          FT_FRAME_ULONG( Length ),
        FT_FRAME_END
      };
  
  
      if ( FT_STREAM_SEEK( offset ) )
        goto Exit;
  
      for ( nn = 0; nn < sfnt->num_tables; nn++ )
      {
        TT_TableRec  table;
  
  
        if ( FT_STREAM_READ_FIELDS( table_dir_entry_fields, &table ) )
        {
          FT_TRACE2(( "check_table_dir:"
                      " can read only %hu table%s in font (instead of %hu)\n",
                      nn, nn == 1 ? "" : "s", sfnt->num_tables ));
          sfnt->num_tables = nn;
          break;
        }
  
        /* we ignore invalid tables */
  
        if ( table.Offset > stream->size )
        {
          FT_TRACE2(( "check_table_dir: table entry %hu invalid\n", nn ));
          continue;
        }
        else if ( table.Length > stream->size - table.Offset )
        {
          /* Some tables have such a simple structure that clipping its     */
          /* contents is harmless.  This also makes FreeType less sensitive */
          /* to invalid table lengths (which programs like Acroread seem to */
          /* ignore in general).                                            */
  
          if ( table.Tag == TTAG_hmtx ||
               table.Tag == TTAG_vmtx )
            valid_entries++;
          else
          {
            FT_TRACE2(( "check_table_dir: table entry %hu invalid\n", nn ));
            continue;
          }
        }
        else
          valid_entries++;
  
        if ( table.Tag == TTAG_head || table.Tag == TTAG_bhed )
        {
          FT_UInt32  magic;
  
  
  #ifndef TT_CONFIG_OPTION_EMBEDDED_BITMAPS
          if ( table.Tag == TTAG_head )
  #endif
            has_head = 1;
  
          /*
           * The table length should be 0x36, but certain font tools make it
           * 0x38, so we will just check that it is greater.
           *
           * Note that according to the specification, the table must be
           * padded to 32-bit lengths, but this doesn't apply to the value of
           * its `Length' field!
           *
           */
          if ( table.Length < 0x36 )
          {
            FT_TRACE2(( "check_table_dir:"
                        " `head' or `bhed' table too small\n" ));
            error = FT_THROW( Table_Missing );
            goto Exit;
          }
  
          if ( FT_STREAM_SEEK( table.Offset + 12 ) ||
               FT_READ_ULONG( magic )              )
            goto Exit;
  
          if ( magic != 0x5F0F3CF5UL )
            FT_TRACE2(( "check_table_dir:"
                        " invalid magic number in `head' or `bhed' table\n"));
  
          if ( FT_STREAM_SEEK( offset + ( nn + 1 ) * 16 ) )
            goto Exit;
        }
        else if ( table.Tag == TTAG_SING )
          has_sing = 1;
        else if ( table.Tag == TTAG_META )
          has_meta = 1;
      }
  
      *valid = valid_entries;
  
      if ( !valid_entries )
      {
        FT_TRACE2(( "check_table_dir: no valid tables found\n" ));
        error = FT_THROW( Unknown_File_Format );
        goto Exit;
      }
  
      /* if `sing' and `meta' tables are present, there is no `head' table */
      if ( has_head || ( has_sing && has_meta ) )
      {
        error = FT_Err_Ok;
        goto Exit;
      }
      else
      {
        FT_TRACE2(( "check_table_dir:" ));
  #ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS
        FT_TRACE2(( " neither `head', `bhed', nor `sing' table found\n" ));
  #else
        FT_TRACE2(( " neither `head' nor `sing' table found\n" ));
  #endif
        error = FT_THROW( Table_Missing );
      }
  
    Exit:
      return error;
    }
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_load_font_dir
     *
     * @Description:
     *   Loads the header of a SFNT font file.
     *
     * @Input:
     *   face ::
     *     A handle to the target face object.
     *
     *   stream ::
     *     The input stream.
     *
     * @Output:
     *   sfnt ::
     *     The SFNT header.
     *
     * @Return:
     *   FreeType error code.  0 means success.
     *
     * @Note:
     *   The stream cursor must be at the beginning of the font directory.
     */
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_font_dir( TT_Face    face,
                           FT_Stream  stream )
    {
      SFNT_HeaderRec  sfnt;
      FT_Error        error;
      FT_Memory       memory = stream->memory;
      FT_UShort       nn, valid_entries = 0;
  
      static const FT_Frame_Field  offset_table_fields[] =
      {
  #undef  FT_STRUCTURE
  #define FT_STRUCTURE  SFNT_HeaderRec
  
        FT_FRAME_START( 8 ),
          FT_FRAME_USHORT( num_tables ),
          FT_FRAME_USHORT( search_range ),
          FT_FRAME_USHORT( entry_selector ),
          FT_FRAME_USHORT( range_shift ),
        FT_FRAME_END
      };
  
  
      FT_TRACE2(( "tt_face_load_font_dir: %p\n", (void *)face ));
  
      /* read the offset table */
  
      sfnt.offset = FT_STREAM_POS();
  
      if ( FT_READ_ULONG( sfnt.format_tag )                    ||
           FT_STREAM_READ_FIELDS( offset_table_fields, &sfnt ) )
        goto Exit;
  
      /* many fonts don't have these fields set correctly */
  #if 0
      if ( sfnt.search_range != 1 << ( sfnt.entry_selector + 4 )        ||
           sfnt.search_range + sfnt.range_shift != sfnt.num_tables << 4 )
        return FT_THROW( Unknown_File_Format );
  #endif
  
      /* load the table directory */
  
      FT_TRACE2(( "-- Number of tables: %10hu\n",   sfnt.num_tables ));
      FT_TRACE2(( "-- Format version:   0x%08lx\n", sfnt.format_tag ));
  
      if ( sfnt.format_tag != TTAG_OTTO )
      {
        /* check first */
        error = check_table_dir( &sfnt, stream, &valid_entries );
        if ( error )
        {
          FT_TRACE2(( "tt_face_load_font_dir:"
                      " invalid table directory for TrueType\n" ));
          goto Exit;
        }
      }
      else
      {
        valid_entries = sfnt.num_tables;
        if ( !valid_entries )
        {
          FT_TRACE2(( "tt_face_load_font_dir: no valid tables found\n" ));
          error = FT_THROW( Unknown_File_Format );
          goto Exit;
        }
      }
  
      face->num_tables = valid_entries;
      face->format_tag = sfnt.format_tag;
  
      if ( FT_QNEW_ARRAY( face->dir_tables, face->num_tables ) )
        goto Exit;
  
      if ( FT_STREAM_SEEK( sfnt.offset + 12 )      ||
           FT_FRAME_ENTER( sfnt.num_tables * 16L ) )
        goto Exit;
  
      FT_TRACE2(( "\n" ));
      FT_TRACE2(( "  tag    offset    length   checksum\n" ));
      FT_TRACE2(( "  ----------------------------------\n" ));
  
      valid_entries = 0;
      for ( nn = 0; nn < sfnt.num_tables; nn++ )
      {
        TT_TableRec  entry;
        FT_UShort    i;
        FT_Bool      duplicate;
  
  
        entry.Tag      = FT_GET_TAG4();
        entry.CheckSum = FT_GET_ULONG();
        entry.Offset   = FT_GET_ULONG();
        entry.Length   = FT_GET_ULONG();
  
        /* ignore invalid tables that can't be sanitized */
  
        if ( entry.Offset > stream->size )
          continue;
        else if ( entry.Length > stream->size - entry.Offset )
        {
          if ( entry.Tag == TTAG_hmtx ||
               entry.Tag == TTAG_vmtx )
          {
  #ifdef FT_DEBUG_LEVEL_TRACE
            FT_ULong  old_length = entry.Length;
  #endif
  
  
            /* make metrics table length a multiple of 4 */
            entry.Length = ( stream->size - entry.Offset ) & ~3U;
  
            FT_TRACE2(( "  %c%c%c%c  %08lx  %08lx  %08lx"
                        " (sanitized; original length %08lx)",
                        (FT_Char)( entry.Tag >> 24 ),
                        (FT_Char)( entry.Tag >> 16 ),
                        (FT_Char)( entry.Tag >> 8  ),
                        (FT_Char)( entry.Tag       ),
                        entry.Offset,
                        entry.Length,
                        entry.CheckSum,
                        old_length ));
          }
          else
            continue;
        }
  #ifdef FT_DEBUG_LEVEL_TRACE
        else
          FT_TRACE2(( "  %c%c%c%c  %08lx  %08lx  %08lx",
                      (FT_Char)( entry.Tag >> 24 ),
                      (FT_Char)( entry.Tag >> 16 ),
                      (FT_Char)( entry.Tag >> 8  ),
                      (FT_Char)( entry.Tag       ),
                      entry.Offset,
                      entry.Length,
                      entry.CheckSum ));
  #endif
  
        /* ignore duplicate tables – the first one wins */
        duplicate = 0;
        for ( i = 0; i < valid_entries; i++ )
        {
          if ( face->dir_tables[i].Tag == entry.Tag )
          {
            duplicate = 1;
            break;
          }
        }
        if ( duplicate )
        {
          FT_TRACE2(( "  (duplicate, ignored)\n" ));
          continue;
        }
        else
        {
          FT_TRACE2(( "\n" ));
  
          /* we finally have a valid entry */
          face->dir_tables[valid_entries++] = entry;
        }
      }
  
      /* final adjustment to number of tables */
      face->num_tables = valid_entries;
  
      FT_FRAME_EXIT();
  
      if ( !valid_entries )
      {
        FT_TRACE2(( "tt_face_load_font_dir: no valid tables found\n" ));
        error = FT_THROW( Unknown_File_Format );
        goto Exit;
      }
  
      FT_TRACE2(( "table directory loaded\n" ));
      FT_TRACE2(( "\n" ));
  
    Exit:
      return error;
    }
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_load_any
     *
     * @Description:
     *   Loads any font table into client memory.
     *
     * @Input:
     *   face ::
     *     The face object to look for.
     *
     *   tag ::
     *     The tag of table to load.  Use the value 0 if you want
     *     to access the whole font file, else set this parameter
     *     to a valid TrueType table tag that you can forge with
     *     the MAKE_TT_TAG macro.
     *
     *   offset ::
     *     The starting offset in the table (or the file if
     *     tag == 0).
     *
     *   length ::
     *     The address of the decision variable:
     *
     *     If length == NULL:
     *       Loads the whole table.  Returns an error if
     *       `offset' == 0!
     *
     *     If *length == 0:
     *       Exits immediately; returning the length of the given
     *       table or of the font file, depending on the value of
     *       `tag'.
     *
     *     If *length != 0:
     *       Loads the next `length' bytes of table or font,
     *       starting at offset `offset' (in table or font too).
     *
     * @Output:
     *   buffer ::
     *     The address of target buffer.
     *
     * @Return:
     *   FreeType error code.  0 means success.
     */
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_any( TT_Face    face,
                      FT_ULong   tag,
                      FT_Long    offset,
                      FT_Byte*   buffer,
                      FT_ULong*  length )
    {
      FT_Error   error;
      FT_Stream  stream;
      TT_Table   table;
      FT_ULong   size;
  
  
      if ( tag != 0 )
      {
        /* look for tag in font directory */
        table = tt_face_lookup_table( face, tag );
        if ( !table )
        {
          error = FT_THROW( Table_Missing );
          goto Exit;
        }
  
        offset += table->Offset;
        size    = table->Length;
      }
      else
        /* tag == 0 -- the user wants to access the font file directly */
        size = face->root.stream->size;
  
      if ( length && *length == 0 )
      {
        *length = size;
  
        return FT_Err_Ok;
      }
  
      if ( length )
        size = *length;
  
      stream = face->root.stream;
      /* the `if' is syntactic sugar for picky compilers */
      if ( FT_STREAM_READ_AT( offset, buffer, size ) )
        goto Exit;
  
    Exit:
      return error;
    }
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_load_generic_header
     *
     * @Description:
     *   Loads the TrueType table `head' or `bhed'.
     *
     * @Input:
     *   face ::
     *     A handle to the target face object.
     *
     *   stream ::
     *     The input stream.
     *
     * @Return:
     *   FreeType error code.  0 means success.
     */
    static FT_Error
    tt_face_load_generic_header( TT_Face    face,
                                 FT_Stream  stream,
                                 FT_ULong   tag )
    {
      FT_Error    error;
      TT_Header*  header;
  
      static const FT_Frame_Field  header_fields[] =
      {
  #undef  FT_STRUCTURE
  #define FT_STRUCTURE  TT_Header
  
        FT_FRAME_START( 54 ),
          FT_FRAME_ULONG ( Table_Version ),
          FT_FRAME_ULONG ( Font_Revision ),
          FT_FRAME_LONG  ( CheckSum_Adjust ),
          FT_FRAME_LONG  ( Magic_Number ),
          FT_FRAME_USHORT( Flags ),
          FT_FRAME_USHORT( Units_Per_EM ),
          FT_FRAME_ULONG ( Created[0] ),
          FT_FRAME_ULONG ( Created[1] ),
          FT_FRAME_ULONG ( Modified[0] ),
          FT_FRAME_ULONG ( Modified[1] ),
          FT_FRAME_SHORT ( xMin ),
          FT_FRAME_SHORT ( yMin ),
          FT_FRAME_SHORT ( xMax ),
          FT_FRAME_SHORT ( yMax ),
          FT_FRAME_USHORT( Mac_Style ),
          FT_FRAME_USHORT( Lowest_Rec_PPEM ),
          FT_FRAME_SHORT ( Font_Direction ),
          FT_FRAME_SHORT ( Index_To_Loc_Format ),
          FT_FRAME_SHORT ( Glyph_Data_Format ),
        FT_FRAME_END
      };
  
  
      error = face->goto_table( face, tag, stream, 0 );
      if ( error )
        goto Exit;
  
      header = &face->header;
  
      if ( FT_STREAM_READ_FIELDS( header_fields, header ) )
        goto Exit;
  
      FT_TRACE3(( "Units per EM: %4hu\n", header->Units_Per_EM ));
      FT_TRACE3(( "IndexToLoc:   %4hd\n", header->Index_To_Loc_Format ));
  
    Exit:
      return error;
    }
  
  
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_head( TT_Face    face,
                       FT_Stream  stream )
    {
      return tt_face_load_generic_header( face, stream, TTAG_head );
    }
  
  
  #ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS
  
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_bhed( TT_Face    face,
                       FT_Stream  stream )
    {
      return tt_face_load_generic_header( face, stream, TTAG_bhed );
    }
  
  #endif /* TT_CONFIG_OPTION_EMBEDDED_BITMAPS */
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_load_maxp
     *
     * @Description:
     *   Loads the maximum profile into a face object.
     *
     * @Input:
     *   face ::
     *     A handle to the target face object.
     *
     *   stream ::
     *     The input stream.
     *
     * @Return:
     *   FreeType error code.  0 means success.
     */
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_maxp( TT_Face    face,
                       FT_Stream  stream )
    {
      FT_Error        error;
      TT_MaxProfile*  maxProfile = &face->max_profile;
  
      static const FT_Frame_Field  maxp_fields[] =
      {
  #undef  FT_STRUCTURE
  #define FT_STRUCTURE  TT_MaxProfile
  
        FT_FRAME_START( 6 ),
          FT_FRAME_LONG  ( version ),
          FT_FRAME_USHORT( numGlyphs ),
        FT_FRAME_END
      };
  
      static const FT_Frame_Field  maxp_fields_extra[] =
      {
        FT_FRAME_START( 26 ),
          FT_FRAME_USHORT( maxPoints ),
          FT_FRAME_USHORT( maxContours ),
          FT_FRAME_USHORT( maxCompositePoints ),
          FT_FRAME_USHORT( maxCompositeContours ),
          FT_FRAME_USHORT( maxZones ),
          FT_FRAME_USHORT( maxTwilightPoints ),
          FT_FRAME_USHORT( maxStorage ),
          FT_FRAME_USHORT( maxFunctionDefs ),
          FT_FRAME_USHORT( maxInstructionDefs ),
          FT_FRAME_USHORT( maxStackElements ),
          FT_FRAME_USHORT( maxSizeOfInstructions ),
          FT_FRAME_USHORT( maxComponentElements ),
          FT_FRAME_USHORT( maxComponentDepth ),
        FT_FRAME_END
      };
  
  
      error = face->goto_table( face, TTAG_maxp, stream, 0 );
      if ( error )
        goto Exit;
  
      if ( FT_STREAM_READ_FIELDS( maxp_fields, maxProfile ) )
        goto Exit;
  
      maxProfile->maxPoints             = 0;
      maxProfile->maxContours           = 0;
      maxProfile->maxCompositePoints    = 0;
      maxProfile->maxCompositeContours  = 0;
      maxProfile->maxZones              = 0;
      maxProfile->maxTwilightPoints     = 0;
      maxProfile->maxStorage            = 0;
      maxProfile->maxFunctionDefs       = 0;
      maxProfile->maxInstructionDefs    = 0;
      maxProfile->maxStackElements      = 0;
      maxProfile->maxSizeOfInstructions = 0;
      maxProfile->maxComponentElements  = 0;
      maxProfile->maxComponentDepth     = 0;
  
      if ( maxProfile->version >= 0x10000L )
      {
        if ( FT_STREAM_READ_FIELDS( maxp_fields_extra, maxProfile ) )
          goto Exit;
  
        /* XXX: an adjustment that is necessary to load certain */
        /*      broken fonts like `Keystrokes MT' :-(           */
        /*                                                      */
        /*   We allocate 64 function entries by default when    */
        /*   the maxFunctionDefs value is smaller.              */
  
        if ( maxProfile->maxFunctionDefs < 64 )
          maxProfile->maxFunctionDefs = 64;
  
        /* we add 4 phantom points later */
        if ( maxProfile->maxTwilightPoints > ( 0xFFFFU - 4 ) )
        {
          FT_TRACE0(( "tt_face_load_maxp:"
                      " too much twilight points in `maxp' table;\n" ));
          FT_TRACE0(( "                  "
                      " some glyphs might be rendered incorrectly\n" ));
  
          maxProfile->maxTwilightPoints = 0xFFFFU - 4;
        }
      }
  
      FT_TRACE3(( "numGlyphs: %hu\n", maxProfile->numGlyphs ));
  
    Exit:
      return error;
    }
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_load_name
     *
     * @Description:
     *   Loads the name records.
     *
     * @Input:
     *   face ::
     *     A handle to the target face object.
     *
     *   stream ::
     *     The input stream.
     *
     * @Return:
     *   FreeType error code.  0 means success.
     */
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_name( TT_Face    face,
                       FT_Stream  stream )
    {
      FT_Error      error;
      FT_Memory     memory = stream->memory;
      FT_ULong      table_pos, table_len;
      FT_ULong      storage_start, storage_limit;
      TT_NameTable  table;
      TT_Name       names    = NULL;
      TT_LangTag    langTags = NULL;
  
      static const FT_Frame_Field  name_table_fields[] =
      {
  #undef  FT_STRUCTURE
  #define FT_STRUCTURE  TT_NameTableRec
  
        FT_FRAME_START( 6 ),
          FT_FRAME_USHORT( format ),
          FT_FRAME_USHORT( numNameRecords ),
          FT_FRAME_USHORT( storageOffset ),
        FT_FRAME_END
      };
  
      static const FT_Frame_Field  name_record_fields[] =
      {
  #undef  FT_STRUCTURE
  #define FT_STRUCTURE  TT_NameRec
  
        /* no FT_FRAME_START */
          FT_FRAME_USHORT( platformID ),
          FT_FRAME_USHORT( encodingID ),
          FT_FRAME_USHORT( languageID ),
          FT_FRAME_USHORT( nameID ),
          FT_FRAME_USHORT( stringLength ),
          FT_FRAME_USHORT( stringOffset ),
        FT_FRAME_END
      };
  
      static const FT_Frame_Field  langTag_record_fields[] =
      {
  #undef  FT_STRUCTURE
  #define FT_STRUCTURE  TT_LangTagRec
  
        /* no FT_FRAME_START */
          FT_FRAME_USHORT( stringLength ),
          FT_FRAME_USHORT( stringOffset ),
        FT_FRAME_END
      };
  
  
      table         = &face->name_table;
      table->stream = stream;
  
      error = face->goto_table( face, TTAG_name, stream, &table_len );
      if ( error )
        goto Exit;
  
      table_pos = FT_STREAM_POS();
  
      if ( FT_STREAM_READ_FIELDS( name_table_fields, table ) )
        goto Exit;
  
      /* Some popular Asian fonts have an invalid `storageOffset' value (it */
      /* should be at least `6 + 12*numNameRecords').  However, the string  */
      /* offsets, computed as `storageOffset + entry->stringOffset', are    */
      /* valid pointers within the name table...                            */
      /*                                                                    */
      /* We thus can't check `storageOffset' right now.                     */
      /*                                                                    */
      storage_start = table_pos + 6 + 12 * table->numNameRecords;
      storage_limit = table_pos + table_len;
  
      if ( storage_start > storage_limit )
      {
        FT_ERROR(( "tt_face_load_name: invalid `name' table\n" ));
        error = FT_THROW( Name_Table_Missing );
        goto Exit;
      }
  
      /* `name' format 1 contains additional language tag records, */
      /* which we load first                                       */
      if ( table->format == 1 )
      {
        if ( FT_STREAM_SEEK( storage_start )            ||
             FT_READ_USHORT( table->numLangTagRecords ) )
          goto Exit;
  
        storage_start += 2 + 4 * table->numLangTagRecords;
  
        /* allocate language tag records array */
        if ( FT_QNEW_ARRAY( langTags, table->numLangTagRecords ) ||
             FT_FRAME_ENTER( table->numLangTagRecords * 4 )      )
          goto Exit;
  
        /* load language tags */
        {
          TT_LangTag  entry = langTags;
          TT_LangTag  limit = FT_OFFSET( entry, table->numLangTagRecords );
  
  
          for ( ; entry < limit; entry++ )
          {
            (void)FT_STREAM_READ_FIELDS( langTag_record_fields, entry );
  
            /* check that the langTag string is within the table */
            entry->stringOffset += table_pos + table->storageOffset;
            if ( entry->stringOffset                       < storage_start ||
                 entry->stringOffset + entry->stringLength > storage_limit )
            {
              /* invalid entry; ignore it */
              entry->stringLength = 0;
            }
  
            /* mark the string as not yet loaded */
            entry->string = NULL;
          }
  
          table->langTags = langTags;
          langTags        = NULL;
        }
  
        FT_FRAME_EXIT();
  
        (void)FT_STREAM_SEEK( table_pos + 6 );
      }
  
      /* allocate name records array */
      if ( FT_QNEW_ARRAY( names, table->numNameRecords ) ||
           FT_FRAME_ENTER( table->numNameRecords * 12 )  )
        goto Exit;
  
      /* load name records */
      {
        TT_Name  entry = names;
        FT_UInt  count = table->numNameRecords;
        FT_UInt  valid = 0;
  
  
        for ( ; count > 0; count-- )
        {
          if ( FT_STREAM_READ_FIELDS( name_record_fields, entry ) )
            continue;
  
          /* check that the name is not empty */
          if ( entry->stringLength == 0 )
            continue;
  
          /* check that the name string is within the table */
          entry->stringOffset += table_pos + table->storageOffset;
          if ( entry->stringOffset                       < storage_start ||
               entry->stringOffset + entry->stringLength > storage_limit )
          {
            /* invalid entry; ignore it */
            continue;
          }
  
          /* assure that we have a valid language tag ID, and   */
          /* that the corresponding langTag entry is valid, too */
          if ( table->format == 1 && entry->languageID >= 0x8000U )
          {
            if ( entry->languageID - 0x8000U >= table->numLangTagRecords    ||
                 !table->langTags[entry->languageID - 0x8000U].stringLength )
            {
              /* invalid entry; ignore it */
              continue;
            }
          }
  
          /* mark the string as not yet converted */
          entry->string = NULL;
  
          valid++;
          entry++;
        }
  
        /* reduce array size to the actually used elements */
        FT_MEM_QRENEW_ARRAY( names,
                             table->numNameRecords,
                             valid );
        table->names          = names;
        names                 = NULL;
        table->numNameRecords = valid;
      }
  
      FT_FRAME_EXIT();
  
      /* everything went well, update face->num_names */
      face->num_names = (FT_UShort)table->numNameRecords;
  
    Exit:
      FT_FREE( names );
      FT_FREE( langTags );
      return error;
    }
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_free_name
     *
     * @Description:
     *   Frees the name records.
     *
     * @Input:
     *   face ::
     *     A handle to the target face object.
     */
    FT_LOCAL_DEF( void )
    tt_face_free_name( TT_Face  face )
    {
      FT_Memory     memory = face->root.driver->root.memory;
      TT_NameTable  table  = &face->name_table;
  
  
      if ( table->names )
      {
        TT_Name  entry = table->names;
        TT_Name  limit = entry + table->numNameRecords;
  
  
        for ( ; entry < limit; entry++ )
          FT_FREE( entry->string );
  
        FT_FREE( table->names );
      }
  
      if ( table->langTags )
      {
        TT_LangTag  entry = table->langTags;
        TT_LangTag  limit = entry + table->numLangTagRecords;
  
  
        for ( ; entry < limit; entry++ )
          FT_FREE( entry->string );
  
        FT_FREE( table->langTags );
      }
  
      table->numNameRecords    = 0;
      table->numLangTagRecords = 0;
      table->format            = 0;
      table->storageOffset     = 0;
    }
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_load_cmap
     *
     * @Description:
     *   Loads the cmap directory in a face object.  The cmaps themselves
     *   are loaded on demand in the `ttcmap.c' module.
     *
     * @Input:
     *   face ::
     *     A handle to the target face object.
     *
     *   stream ::
     *     A handle to the input stream.
     *
     * @Return:
     *   FreeType error code.  0 means success.
     */
  
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_cmap( TT_Face    face,
                       FT_Stream  stream )
    {
      FT_Error  error;
  
  
      error = face->goto_table( face, TTAG_cmap, stream, &face->cmap_size );
      if ( error )
        goto Exit;
  
      if ( FT_FRAME_EXTRACT( face->cmap_size, face->cmap_table ) )
        face->cmap_size = 0;
  
    Exit:
      return error;
    }
  
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_load_os2
     *
     * @Description:
     *   Loads the OS2 table.
     *
     * @Input:
     *   face ::
     *     A handle to the target face object.
     *
     *   stream ::
     *     A handle to the input stream.
     *
     * @Return:
     *   FreeType error code.  0 means success.
     */
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_os2( TT_Face    face,
                      FT_Stream  stream )
    {
      FT_Error  error;
      TT_OS2*   os2;
  
      static const FT_Frame_Field  os2_fields[] =
      {
  #undef  FT_STRUCTURE
  #define FT_STRUCTURE  TT_OS2
  
        FT_FRAME_START( 78 ),
          FT_FRAME_USHORT( version ),
          FT_FRAME_SHORT ( xAvgCharWidth ),
          FT_FRAME_USHORT( usWeightClass ),
          FT_FRAME_USHORT( usWidthClass ),
          FT_FRAME_SHORT ( fsType ),
          FT_FRAME_SHORT ( ySubscriptXSize ),
          FT_FRAME_SHORT ( ySubscriptYSize ),
          FT_FRAME_SHORT ( ySubscriptXOffset ),
          FT_FRAME_SHORT ( ySubscriptYOffset ),
          FT_FRAME_SHORT ( ySuperscriptXSize ),
          FT_FRAME_SHORT ( ySuperscriptYSize ),
          FT_FRAME_SHORT ( ySuperscriptXOffset ),
          FT_FRAME_SHORT ( ySuperscriptYOffset ),
          FT_FRAME_SHORT ( yStrikeoutSize ),
          FT_FRAME_SHORT ( yStrikeoutPosition ),
          FT_FRAME_SHORT ( sFamilyClass ),
          FT_FRAME_BYTE  ( panose[0] ),
          FT_FRAME_BYTE  ( panose[1] ),
          FT_FRAME_BYTE  ( panose[2] ),
          FT_FRAME_BYTE  ( panose[3] ),
          FT_FRAME_BYTE  ( panose[4] ),
          FT_FRAME_BYTE  ( panose[5] ),
          FT_FRAME_BYTE  ( panose[6] ),
          FT_FRAME_BYTE  ( panose[7] ),
          FT_FRAME_BYTE  ( panose[8] ),
          FT_FRAME_BYTE  ( panose[9] ),
          FT_FRAME_ULONG ( ulUnicodeRange1 ),
          FT_FRAME_ULONG ( ulUnicodeRange2 ),
          FT_FRAME_ULONG ( ulUnicodeRange3 ),
          FT_FRAME_ULONG ( ulUnicodeRange4 ),
          FT_FRAME_BYTE  ( achVendID[0] ),
          FT_FRAME_BYTE  ( achVendID[1] ),
          FT_FRAME_BYTE  ( achVendID[2] ),
          FT_FRAME_BYTE  ( achVendID[3] ),
  
          FT_FRAME_USHORT( fsSelection ),
          FT_FRAME_USHORT( usFirstCharIndex ),
          FT_FRAME_USHORT( usLastCharIndex ),
          FT_FRAME_SHORT ( sTypoAscender ),
          FT_FRAME_SHORT ( sTypoDescender ),
          FT_FRAME_SHORT ( sTypoLineGap ),
          FT_FRAME_USHORT( usWinAscent ),
          FT_FRAME_USHORT( usWinDescent ),
        FT_FRAME_END
      };
  
      /* `OS/2' version 1 and newer */
      static const FT_Frame_Field  os2_fields_extra1[] =
      {
        FT_FRAME_START( 8 ),
          FT_FRAME_ULONG( ulCodePageRange1 ),
          FT_FRAME_ULONG( ulCodePageRange2 ),
        FT_FRAME_END
      };
  
      /* `OS/2' version 2 and newer */
      static const FT_Frame_Field  os2_fields_extra2[] =
      {
        FT_FRAME_START( 10 ),
          FT_FRAME_SHORT ( sxHeight ),
          FT_FRAME_SHORT ( sCapHeight ),
          FT_FRAME_USHORT( usDefaultChar ),
          FT_FRAME_USHORT( usBreakChar ),
          FT_FRAME_USHORT( usMaxContext ),
        FT_FRAME_END
      };
  
      /* `OS/2' version 5 and newer */
      static const FT_Frame_Field  os2_fields_extra5[] =
      {
        FT_FRAME_START( 4 ),
          FT_FRAME_USHORT( usLowerOpticalPointSize ),
          FT_FRAME_USHORT( usUpperOpticalPointSize ),
        FT_FRAME_END
      };
  
  
      /* We now support old Mac fonts where the OS/2 table doesn't  */
      /* exist.  Simply put, we set the `version' field to 0xFFFF   */
      /* and test this value each time we need to access the table. */
      error = face->goto_table( face, TTAG_OS2, stream, 0 );
      if ( error )
        goto Exit;
  
      os2 = &face->os2;
  
      if ( FT_STREAM_READ_FIELDS( os2_fields, os2 ) )
        goto Exit;
  
      os2->ulCodePageRange1        = 0;
      os2->ulCodePageRange2        = 0;
      os2->sxHeight                = 0;
      os2->sCapHeight              = 0;
      os2->usDefaultChar           = 0;
      os2->usBreakChar             = 0;
      os2->usMaxContext            = 0;
      os2->usLowerOpticalPointSize = 0;
      os2->usUpperOpticalPointSize = 0xFFFF;
  
      if ( os2->version >= 0x0001 )
      {
        /* only version 1 tables */
        if ( FT_STREAM_READ_FIELDS( os2_fields_extra1, os2 ) )
          goto Exit;
  
        if ( os2->version >= 0x0002 )
        {
          /* only version 2 tables */
          if ( FT_STREAM_READ_FIELDS( os2_fields_extra2, os2 ) )
            goto Exit;
  
          if ( os2->version >= 0x0005 )
          {
            /* only version 5 tables */
            if ( FT_STREAM_READ_FIELDS( os2_fields_extra5, os2 ) )
              goto Exit;
          }
        }
      }
  
      FT_TRACE3(( "sTypoAscender:  %4hd\n",   os2->sTypoAscender ));
      FT_TRACE3(( "sTypoDescender: %4hd\n",   os2->sTypoDescender ));
      FT_TRACE3(( "usWinAscent:    %4hu\n",   os2->usWinAscent ));
      FT_TRACE3(( "usWinDescent:   %4hu\n",   os2->usWinDescent ));
      FT_TRACE3(( "fsSelection:    0x%2hx\n", os2->fsSelection ));
  
    Exit:
      return error;
    }
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_load_postscript
     *
     * @Description:
     *   Loads the Postscript table.
     *
     * @Input:
     *   face ::
     *     A handle to the target face object.
     *
     *   stream ::
     *     A handle to the input stream.
     *
     * @Return:
     *   FreeType error code.  0 means success.
     */
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_post( TT_Face    face,
                       FT_Stream  stream )
    {
      FT_Error        error;
      TT_Postscript*  post = &face->postscript;
  
      static const FT_Frame_Field  post_fields[] =
      {
  #undef  FT_STRUCTURE
  #define FT_STRUCTURE  TT_Postscript
  
        FT_FRAME_START( 32 ),
          FT_FRAME_LONG ( FormatType ),
          FT_FRAME_LONG ( italicAngle ),
          FT_FRAME_SHORT( underlinePosition ),
          FT_FRAME_SHORT( underlineThickness ),
          FT_FRAME_ULONG( isFixedPitch ),
          FT_FRAME_ULONG( minMemType42 ),
          FT_FRAME_ULONG( maxMemType42 ),
          FT_FRAME_ULONG( minMemType1 ),
          FT_FRAME_ULONG( maxMemType1 ),
        FT_FRAME_END
      };
  
  
      error = face->goto_table( face, TTAG_post, stream, 0 );
      if ( error )
        return error;
  
      if ( FT_STREAM_READ_FIELDS( post_fields, post ) )
        return error;
  
      if ( post->FormatType != 0x00030000L &&
           post->FormatType != 0x00025000L &&
           post->FormatType != 0x00020000L &&
           post->FormatType != 0x00010000L )
        return FT_THROW( Invalid_Post_Table_Format );
  
      /* we don't load the glyph names, we do that in another */
      /* module (ttpost).                                     */
  
      FT_TRACE3(( "FormatType:   0x%lx\n", post->FormatType ));
      FT_TRACE3(( "isFixedPitch:   %s\n", post->isFixedPitch
                                          ? "  yes" : "   no" ));
  
      return FT_Err_Ok;
    }
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_load_pclt
     *
     * @Description:
     *   Loads the PCL 5 Table.
     *
     * @Input:
     *   face ::
     *     A handle to the target face object.
     *
     *   stream ::
     *     A handle to the input stream.
     *
     * @Return:
     *   FreeType error code.  0 means success.
     */
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_pclt( TT_Face    face,
                       FT_Stream  stream )
    {
      static const FT_Frame_Field  pclt_fields[] =
      {
  #undef  FT_STRUCTURE
  #define FT_STRUCTURE  TT_PCLT
  
        FT_FRAME_START( 54 ),
          FT_FRAME_ULONG ( Version ),
          FT_FRAME_ULONG ( FontNumber ),
          FT_FRAME_USHORT( Pitch ),
          FT_FRAME_USHORT( xHeight ),
          FT_FRAME_USHORT( Style ),
          FT_FRAME_USHORT( TypeFamily ),
          FT_FRAME_USHORT( CapHeight ),
          FT_FRAME_USHORT( SymbolSet ),
          FT_FRAME_BYTES ( TypeFace, 16 ),
          FT_FRAME_BYTES ( CharacterComplement, 8 ),
          FT_FRAME_BYTES ( FileName, 6 ),
          FT_FRAME_CHAR  ( StrokeWeight ),
          FT_FRAME_CHAR  ( WidthType ),
          FT_FRAME_BYTE  ( SerifStyle ),
          FT_FRAME_BYTE  ( Reserved ),
        FT_FRAME_END
      };
  
      FT_Error  error;
      TT_PCLT*  pclt = &face->pclt;
  
  
      /* optional table */
      error = face->goto_table( face, TTAG_PCLT, stream, 0 );
      if ( error )
        goto Exit;
  
      if ( FT_STREAM_READ_FIELDS( pclt_fields, pclt ) )
        goto Exit;
  
    Exit:
      return error;
    }
  
  
    /**************************************************************************
     *
     * @Function:
     *   tt_face_load_gasp
     *
     * @Description:
     *   Loads the `gasp' table into a face object.
     *
     * @Input:
     *   face ::
     *     A handle to the target face object.
     *
     *   stream ::
     *     The input stream.
     *
     * @Return:
     *   FreeType error code.  0 means success.
     */
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_gasp( TT_Face    face,
                       FT_Stream  stream )
    {
      FT_Error   error;
      FT_Memory  memory = stream->memory;
  
      FT_UShort      j, num_ranges;
      TT_GaspRange   gasp_ranges = NULL;
  
  
      /* the gasp table is optional */
      error = face->goto_table( face, TTAG_gasp, stream, 0 );
      if ( error )
        goto Exit;
  
      if ( FT_FRAME_ENTER( 4L ) )
        goto Exit;
  
      face->gasp.version = FT_GET_USHORT();
      num_ranges         = FT_GET_USHORT();
  
      FT_FRAME_EXIT();
  
      /* only support versions 0 and 1 of the table */
      if ( face->gasp.version >= 2 )
      {
        face->gasp.numRanges = 0;
        error = FT_THROW( Invalid_Table );
        goto Exit;
      }
  
      FT_TRACE3(( "numRanges: %hu\n", num_ranges ));
  
      if ( FT_QNEW_ARRAY( gasp_ranges, num_ranges ) ||
           FT_FRAME_ENTER( num_ranges * 4L )        )
        goto Exit;
  
      for ( j = 0; j < num_ranges; j++ )
      {
        gasp_ranges[j].maxPPEM  = FT_GET_USHORT();
        gasp_ranges[j].gaspFlag = FT_GET_USHORT();
  
        FT_TRACE3(( "gaspRange %hu: rangeMaxPPEM %5hu, rangeGaspBehavior 0x%hx\n",
                    j,
                    gasp_ranges[j].maxPPEM,
                    gasp_ranges[j].gaspFlag ));
      }
  
      face->gasp.gaspRanges = gasp_ranges;
      gasp_ranges           = NULL;
      face->gasp.numRanges  = num_ranges;
  
      FT_FRAME_EXIT();
  
    Exit:
      FT_FREE( gasp_ranges );
      return error;
    }
  
  
  /* END */
  

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