ftxgsub.c

这个是Linux的qt源代码

    Free_Coverage( &ls->Coverage, memory );
    return error;
  }


  void  Free_LigatureSubst( TTO_LigatureSubst*  ls,
			    FT_Memory           memory )
  {
    FT_UShort         n, count;

    TTO_LigatureSet*  lset;


    if ( ls->LigatureSet )
    {
      count = ls->LigatureSetCount;
      lset  = ls->LigatureSet;

      for ( n = 0; n < count; n++ )
        Free_LigatureSet( &lset[n], memory );

      FREE( lset );
    }

    Free_Coverage( &ls->Coverage, memory );
  }


  static FT_Error  Lookup_LigatureSubst( TTO_LigatureSubst*  ls,
                                         TTO_GSUB_String*    in,
                                         TTO_GSUB_String*    out,
                                         FT_UShort           flags,
                                         FT_UShort           context_length,
                                         TTO_GDEFHeader*     gdef )
  {
    FT_UShort      index, property;
    FT_Error       error;
    FT_UShort      numlig, i, j, is_mark, first_is_mark = FALSE;
    FT_UShort*     s_in;
    FT_UShort*     c;

    TTO_Ligature*  lig;

    error = Coverage_Index( &ls->Coverage, in->string[in->pos], &index );
    if ( error )
      return error;

    if ( CHECK_Property( gdef, in->string[in->pos], flags, &property ) )
      return error;

    if ( property == TTO_MARK || property & IGNORE_SPECIAL_MARKS )
      first_is_mark = TRUE;

    if ( index >= ls->LigatureSetCount )
       return TTO_Err_Invalid_GSUB_SubTable;

    lig = ls->LigatureSet[index].Ligature;

    for ( numlig = ls->LigatureSet[index].LigatureCount;
          numlig;
          numlig--, lig++ )
    {
      if ( in->pos + lig->ComponentCount > in->length )
        continue;                         /* Not enough glyphs in input */

      s_in = &in->string[in->pos];
      c    = lig->Component;

      is_mark = first_is_mark;

      if ( context_length != 0xFFFF && context_length < lig->ComponentCount )
        break;

      for ( i = 1, j = 1; i < lig->ComponentCount; i++, j++ )
      {
        while ( in->pos + j < in->length
		&& CHECK_Property( gdef, s_in[j], flags, &property ) )
        {
          if ( error && error != TTO_Err_Not_Covered )
            return error;

	  j++;
        }

        if ( !( property == TTO_MARK || property & IGNORE_SPECIAL_MARKS ) )
          is_mark = FALSE;

        if ( in->pos + j >= in->length || s_in[j] != c[i - 1] )
          break;
      }

      if ( i == lig->ComponentCount )
      {
        if ( gdef && gdef->NewGlyphClasses )
        {
          /* this is just a guess ... */

          error = Add_Glyph_Property( gdef, lig->LigGlyph,
                                      is_mark ? TTO_MARK : TTO_LIGATURE );
          if ( error && error != TTO_Err_Not_Covered )
            return error;
        }

        if ( i == j )
        {
	  glyph_copy( in, i, out, lig->LigGlyph,
		      in->glyph_properties[in->pos].component );
        }
        else
        {
	  glyph_copy( in, 1, out, lig->LigGlyph,
		      in->glyph_properties[in->pos].component);

          /* Now we must do a second loop to copy the skipped glyphs to
             `out' and assign component values to it.  We start with the
             glyph after the first component.  Glyphs between component
             i and i+1 belong to component i.  Together with the ligID
             value it is later possible to check whether a specific
             component value really belongs to a given ligature.         */

          for ( i = 0; i < lig->ComponentCount - 1; i++ )
          {
            while ( CHECK_Property( gdef, in->string[in->pos],
                                    flags, &property ) )
		glyph_copy( in, 1, out, in->string[in->pos], i);
            (in->pos)++;
          }
        }

        return TT_Err_Ok;
      }
    }

    return TTO_Err_Not_Covered;
  }


  /* Do the actual substitution for a context substitution (either format
     5 or 6).  This is only called after we've determined that the input
     matches the subrule.                                                 */

  static FT_Error  Do_ContextSubst( TTO_GSUBHeader*         gsub,
                                    FT_UShort               GlyphCount,
                                    FT_UShort               SubstCount,
                                    TTO_SubstLookupRecord*  subst,
                                    TTO_GSUB_String*        in,
                                    TTO_GSUB_String*        out,
                                    int                     nesting_level )
  {
    FT_Error  error;
    FT_UShort i, old_pos;


    i = 0;

    while ( i < GlyphCount )
    {
      if ( SubstCount && i == subst->SequenceIndex )
      {
        old_pos = in->pos;

        /* Do a substitution */

        error = GSub_Do_Glyph_Lookup( gsub, subst->LookupListIndex, in, out,
                                 GlyphCount, nesting_level );

        subst++;
        SubstCount--;
        i += in->pos - old_pos;

        if ( error == TTO_Err_Not_Covered )
        {
          /* XXX "can't happen" -- but don't count on it */

	  glyph_copy( in, 1, out, in->string[in->pos],
		      in->glyph_properties[in->pos].component);
          i++;
        }
        else if ( error )
          return error;
      }
      else
      {
        /* No substitution for this index */

	  glyph_copy( in, 1, out, in->string[in->pos],
		      in->glyph_properties[in->pos].component);
          return error;
        i++;
      }
    }

    return TT_Err_Ok;
  }


  /* LookupType 5 */

  /* SubRule */

  static FT_Error  Load_SubRule( TTO_SubRule*  sr,
                                 FT_Stream     stream )
  {
    FT_Error error;
    FT_Memory memory = stream->memory;

    FT_UShort               n, count;
    FT_UShort*              i;

    TTO_SubstLookupRecord*  slr;


    if ( ACCESS_Frame( 4L ) )
      return error;

    sr->GlyphCount = GET_UShort();
    sr->SubstCount = GET_UShort();

    FORGET_Frame();

    sr->Input = NULL;

    count = sr->GlyphCount - 1;         /* only GlyphCount - 1 elements */

    if ( ALLOC_ARRAY( sr->Input, count, FT_UShort ) )
      return error;

    i = sr->Input;

    if ( ACCESS_Frame( count * 2L ) )
      goto Fail2;

    for ( n = 0; n < count; n++ )
      i[n] = GET_UShort();

    FORGET_Frame();

    sr->SubstLookupRecord = NULL;

    count = sr->SubstCount;

    if ( ALLOC_ARRAY( sr->SubstLookupRecord, count, TTO_SubstLookupRecord ) )
      goto Fail2;

    slr = sr->SubstLookupRecord;

    if ( ACCESS_Frame( count * 4L ) )
      goto Fail1;

    for ( n = 0; n < count; n++ )
    {
      slr[n].SequenceIndex   = GET_UShort();
      slr[n].LookupListIndex = GET_UShort();
    }

    FORGET_Frame();

    return TT_Err_Ok;

  Fail1:
    FREE( slr );

  Fail2:
    FREE( i );
    return error;
  }


  static void  Free_SubRule( TTO_SubRule*  sr,
			     FT_Memory     memory )
  {
    FREE( sr->SubstLookupRecord );
    FREE( sr->Input );
  }


  /* SubRuleSet */

  static FT_Error  Load_SubRuleSet( TTO_SubRuleSet*  srs,
                                    FT_Stream        stream )
  {
    FT_Error error;
    FT_Memory memory = stream->memory;

    FT_UShort     n = 0, m, count;
    FT_ULong      cur_offset, new_offset, base_offset;

    TTO_SubRule*  sr;


    base_offset = FILE_Pos();

    if ( ACCESS_Frame( 2L ) )
      return error;

    count = srs->SubRuleCount = GET_UShort();

    FORGET_Frame();

    srs->SubRule = NULL;

    if ( ALLOC_ARRAY( srs->SubRule, count, TTO_SubRule ) )
      return error;

    sr = srs->SubRule;

    for ( n = 0; n < count; n++ )
    {
      if ( ACCESS_Frame( 2L ) )
        goto Fail;

      new_offset = GET_UShort() + base_offset;

      FORGET_Frame();

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
           ( error = Load_SubRule( &sr[n], stream ) ) != TT_Err_Ok )
        goto Fail;
      (void)FILE_Seek( cur_offset );
    }

    return TT_Err_Ok;

  Fail:
    for ( m = 0; m < n; m++ )
      Free_SubRule( &sr[m], memory );

    FREE( sr );
    return error;
  }


  static void  Free_SubRuleSet( TTO_SubRuleSet*  srs,
				FT_Memory        memory )
  {
    FT_UShort     n, count;

    TTO_SubRule*  sr;


    if ( srs->SubRule )
    {
      count = srs->SubRuleCount;
      sr    = srs->SubRule;

      for ( n = 0; n < count; n++ )
        Free_SubRule( &sr[n], memory );

      FREE( sr );
    }
  }


  /* ContextSubstFormat1 */

  static FT_Error  Load_ContextSubst1( TTO_ContextSubstFormat1*  csf1,
                                       FT_Stream                 stream )
  {
    FT_Error error;
    FT_Memory memory = stream->memory;

    FT_UShort        n = 0, m, count;
    FT_ULong         cur_offset, new_offset, base_offset;

    TTO_SubRuleSet*  srs;


    base_offset = FILE_Pos() - 2L;

    if ( ACCESS_Frame( 2L ) )
      return error;

    new_offset = GET_UShort() + base_offset;

    FORGET_Frame();

    cur_offset = FILE_Pos();
    if ( FILE_Seek( new_offset ) ||
         ( error = Load_Coverage( &csf1->Coverage, stream ) ) != TT_Err_Ok )
      return error;
    (void)FILE_Seek( cur_offset );

    if ( ACCESS_Frame( 2L ) )
      goto Fail2;

    count = csf1->SubRuleSetCount = GET_UShort();

    FORGET_Frame();

    csf1->SubRuleSet = NULL;

    if ( ALLOC_ARRAY( csf1->SubRuleSet, count, TTO_SubRuleSet ) )
      goto Fail2;

    srs = csf1->SubRuleSet;

    for ( n = 0; n < count; n++ )
    {
      if ( ACCESS_Frame( 2L ) )
        goto Fail1;

      new_offset = GET_UShort() + base_offset;

      FORGET_Frame();

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
           ( error = Load_SubRuleSet( &srs[n], stream ) ) != TT_Err_Ok )
        goto Fail1;
      (void)FILE_Seek( cur_offset );
    }

    return TT_Err_Ok;

  Fail1:
    for ( m = 0; m < n; m++ )
      Free_SubRuleSet( &srs[m], memory );

    FREE( srs );

  Fail2:
    Free_Coverage( &csf1->Coverage, memory );
    return error;
  }


  static void  GSub_Free_Context1( TTO_ContextSubstFormat1* csf1,
			      FT_Memory                memory )
  {
    FT_UShort        n, count;

    TTO_SubRuleSet*  srs;


    if ( csf1->SubRuleSet )
    {
      count = csf1->SubRuleSetCount;
      srs   = csf1->SubRuleSet;

      for ( n = 0; n < count; n++ )
        Free_SubRuleSet( &srs[n], memory );

      FREE( srs );
    }

    Free_Coverage( &csf1->Coverage, memory );
  }


  /* SubClassRule */

  static FT_Error  Load_SubClassRule( TTO_ContextSubstFormat2*  csf2,
                                      TTO_SubClassRule*         scr,
                                      FT_Stream                 stream )
  {
    FT_Error error;
    FT_Memory memory = stream->memory;

    FT_UShort               n, count;

    FT_UShort*              c;
    TTO_SubstLookupRecord*  slr;
    FT_Bool*                d;


    if ( ACCESS_Frame( 4L ) )
      return error;

    scr->GlyphCount = GET_UShort();
    scr->SubstCount = GET_UShort();

    if ( scr->GlyphCount > csf2->MaxContextLength )
      csf2->MaxContextLength = scr->GlyphCount;

    FORGET_Frame();

    scr->Class = NULL;

    count = scr->GlyphCount - 1;        /* only GlyphCount - 1 elements */

    if ( ALLOC_ARRAY( scr->Class, count, FT_UShort ) )
      return error;

    c = scr->Class;
    d = csf2->ClassDef.Defined;

    if ( ACCESS_Frame( count * 2L ) )
      goto Fail2;

    for ( n = 0; n < count; n++ )
    {
      c[n] = GET_UShort();

      /* ### see comment in Load_ChainSubClassRule */
      /* We check whether the specific class is used at all.  If not,
         class 0 is used instead.                                     */
      /*
	if ( !d[c[n]] )
	    c[n] = 0;
      */
    }

    FORGET_Frame();

    scr->SubstLookupRecord = NULL;

    count = scr->SubstCount;

    if ( ALLOC_ARRAY( scr->SubstLookupRecord, count, TTO_SubstLookupRecord ) )
      goto Fail2;

    slr = scr->SubstLookupRecord;

    if ( ACCESS_Frame( count * 4L ) )
      goto Fail1;

    for ( n = 0; n < count; n++ )
    {
      slr[n].SequenceIndex   = GET_UShort();
      slr[n].LookupListIndex = GET_UShort();
    }

    FORGET_Frame();

    return TT_Err_Ok;

  Fail1:
    FREE( slr );

  Fail2:
    FREE( c );
    return error;
  }


  static void  Free_SubClassRule( TTO_SubClassRule*  scr,
				  FT_Memory          memory )
  {
    FREE( scr->SubstLookupRecord );
    FREE( scr->Class );
  }


  /* SubClassSet */

  static FT_Error  Load_SubClassSet( TTO_ContextSubstFormat2*  csf2,
                                     TTO_SubClassSet*          scs,
                                     FT_Stream                 stream )
  {
    FT_Error error;
    FT_Memory memory = stream->memory;

    FT_UShort          n = 0, m, count;
    FT_ULong           cur_offset, new_offset, base_offset;

    TTO_SubClassRule*  scr;


    base_offset = FILE_Pos();

    if ( ACCESS_Frame( 2L ) )
      return error;

    count = scs->SubClassRuleCount = GET_UShort();

    FORGET_Frame();