ftxopen.c

这个是Linux的qt源代码

      }
      else if ( glyphID < middle->Start )
      {
        max = middle - 1;
      }
      else
      {
        min = middle + 1;
      }
    } while ( min <= max );

    return TTO_Err_Not_Covered;
  }


  FT_Error  Coverage_Index( TTO_Coverage*  c,
                            FT_UShort      glyphID,
                            FT_UShort*     index )
  {
    if ( c->CoverageFormat == 1 )
      return Coverage_Index1( &c->cf.cf1, glyphID, index );
    else if ( c->CoverageFormat == 2 )
      return Coverage_Index2( &c->cf.cf2, glyphID, index );
    return TTO_Err_Invalid_SubTable_Format;
  }



  /*************************************
   * Class Definition related functions
   *************************************/


  /* ClassDefFormat1 */

  static FT_Error  Load_ClassDef1( TTO_ClassDefinition*  cd,
                                   FT_UShort             limit,
				   FT_Stream             stream )
  {
    FT_Error   error;
    FT_Memory  memory = stream->memory;

    FT_UShort             n, count;

    FT_UShort*            cva;
    FT_Bool*              d;

    TTO_ClassDefFormat1*  cdf1;


    cdf1 = &cd->cd.cd1;

    if ( ACCESS_Frame( 4L ) )
      return error;

    cdf1->StartGlyph         = GET_UShort();
    count = cdf1->GlyphCount = GET_UShort();

    FORGET_Frame();

    /* sanity check; we are limited to 16bit integers */

    if ( cdf1->StartGlyph + (long)count >= 0x10000L )
      return TTO_Err_Invalid_SubTable;

    cdf1->ClassValueArray = NULL;

    if ( ALLOC_ARRAY( cdf1->ClassValueArray, count, FT_UShort ) )
      return error;

    d   = cd->Defined;
    cva = cdf1->ClassValueArray;

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

    for ( n = 0; n < count; n++ )
    {
      cva[n] = GET_UShort();
      if ( cva[n] >= limit )
      {
        error = TTO_Err_Invalid_SubTable;
        goto Fail;
      }
      d[cva[n]] = TRUE;
    }

    FORGET_Frame();

    return TT_Err_Ok;

  Fail:
    FREE( cva );

    return error;
  }


  static void  Free_ClassDef1( TTO_ClassDefFormat1*  cdf1,
			       FT_Memory             memory )
  {
    FREE( cdf1->ClassValueArray );
  }


  /* ClassDefFormat2 */

  static FT_Error  Load_ClassDef2( TTO_ClassDefinition*  cd,
                                   FT_UShort             limit,
				   FT_Stream             stream )
  {
    FT_Error   error;
    FT_Memory  memory = stream->memory;

    FT_UShort              n, count;

    TTO_ClassRangeRecord*  crr;
    FT_Bool*               d;

    TTO_ClassDefFormat2*   cdf2;


    cdf2 = &cd->cd.cd2;

    if ( ACCESS_Frame( 2L ) )
      return error;

    count = cdf2->ClassRangeCount = GET_UShort();

    FORGET_Frame();

    cdf2->ClassRangeRecord = NULL;

    if ( ALLOC_ARRAY( cdf2->ClassRangeRecord, count, TTO_ClassRangeRecord ) )
      return error;

    d   = cd->Defined;
    crr = cdf2->ClassRangeRecord;

    if ( ACCESS_Frame( count * 6L ) )
      goto Fail;

    for ( n = 0; n < count; n++ )
    {
      crr[n].Start = GET_UShort();
      crr[n].End   = GET_UShort();
      crr[n].Class = GET_UShort();

      /* sanity check */

      if ( crr[n].Start > crr[n].End ||
           crr[n].Class >= limit )
      {
        error = TTO_Err_Invalid_SubTable;
        goto Fail;
      }
      d[crr[n].Class] = TRUE;
    }

    FORGET_Frame();

    return TT_Err_Ok;

  Fail:
    FREE( crr );

    return error;
  }


  static void  Free_ClassDef2( TTO_ClassDefFormat2*  cdf2,
			       FT_Memory             memory )
  {
    FREE( cdf2->ClassRangeRecord );
  }


  /* ClassDefinition */

  FT_Error  Load_ClassDefinition( TTO_ClassDefinition*  cd,
                                  FT_UShort             limit,
				  FT_Stream             stream )
  {
    FT_Error   error;
    FT_Memory  memory = stream->memory;


    if ( ALLOC_ARRAY( cd->Defined, limit, FT_Bool ) )
      return error;

    if ( ACCESS_Frame( 2L ) )
      goto Fail;

    cd->ClassFormat = GET_UShort();

    FORGET_Frame();

    switch ( cd->ClassFormat )
    {
    case 1:
      error = Load_ClassDef1( cd, limit, stream );
      break;

    case 2:
      error = Load_ClassDef2( cd, limit, stream );
      break;

    default:
      error = TTO_Err_Invalid_SubTable_Format;
      break;
    }

    if ( error )
      goto Fail;

    cd->loaded = TRUE;

    return TT_Err_Ok;

  Fail:
    FREE( cd->Defined );
    return error;
  }


  FT_Error  Load_EmptyClassDefinition( TTO_ClassDefinition*  cd,
				       FT_Stream             stream )
  {
    FT_Error   error;
    FT_Memory  memory = stream->memory;


    if ( ALLOC_ARRAY( cd->Defined, 1, FT_Bool ) )
      return error;

    cd->ClassFormat = 1; /* Meaningless */
    cd->Defined[0] = FALSE;

    if ( ALLOC_ARRAY( cd->cd.cd1.ClassValueArray, 1, FT_UShort ) )
      goto Fail;

    return TT_Err_Ok;

  Fail:
    FREE( cd->Defined );
    return error;
  }

  void  Free_ClassDefinition( TTO_ClassDefinition*  cd,
			      FT_Memory             memory )
  {
    if ( !cd->loaded )
      return;

    FREE( cd->Defined );

    switch ( cd->ClassFormat )
    {
    case 1:
      Free_ClassDef1( &cd->cd.cd1, memory );
      break;

    case 2:
      Free_ClassDef2( &cd->cd.cd2, memory );
      break;
    }
  }


  static inline FT_Error  Get_Class1( TTO_ClassDefFormat1*  cdf1,
                               FT_UShort             glyphID,
                               FT_UShort*            klass,
                               FT_UShort*            index )
  {
    if (index)
      *index = 0;

    if ( glyphID >= cdf1->StartGlyph &&
         glyphID <= cdf1->StartGlyph + cdf1->GlyphCount )
    {
      *klass = cdf1->ClassValueArray[glyphID - cdf1->StartGlyph];
      return TT_Err_Ok;
    }
    *klass = 0;
    return TTO_Err_Not_Covered;
  }


  /* we need the index value of the last searched class range record
     in case of failure for constructed GDEF tables                  */

  static inline FT_Error  Get_Class2( TTO_ClassDefFormat2*  cdf2,
                               FT_UShort             glyphID,
                               FT_UShort*            klass,
                               FT_UShort*            index )
  {
    FT_Error               error = TTO_Err_Not_Covered;
    int              min, max, middle;

    TTO_ClassRangeRecord*  crr = cdf2->ClassRangeRecord;

    *klass = 0;

    /* binary search */

    min = 0;
    max = cdf2->ClassRangeCount - 1;

    do
    {
      /* we use (min + max) / 2 = max - (max - min) / 2  to avoid
         overflow and rounding errors                             */

      middle = max - ( ( max - min ) >> 1 );

      if ( glyphID >= crr[middle].Start && glyphID <= crr[middle].End )
      {
        *klass = crr[middle].Class;
        return TT_Err_Ok;
      }
      else if ( glyphID < crr[middle].Start )
      {
        max = middle - 1;
      }
      else
      {
        min = middle + 1;
      }
    } while ( min <= max );

    *klass = 0;
    if ( index )
      *index = middle;

    return error;
  }


  inline FT_Error  Get_Class( TTO_ClassDefinition*  cd,
                       FT_UShort             glyphID,
                       FT_UShort*            klass,
                       FT_UShort*            index )
  {
    if ( cd->ClassFormat == 1 )
      return Get_Class1( &cd->cd.cd1, glyphID, klass, index );
    else if ( cd->ClassFormat == 2 )
      return Get_Class2( &cd->cd.cd2, glyphID, klass, index );
    return TTO_Err_Invalid_SubTable_Format;
  }



  /***************************
   * Device related functions
   ***************************/


  FT_Error  Load_Device( TTO_Device*  d,
			 FT_Stream    stream )
  {
    FT_Error   error;
    FT_Memory  memory = stream->memory;

    FT_UShort   n, count;

    FT_UShort*  dv;


    if ( ACCESS_Frame( 6L ) )
      return error;

    d->StartSize   = GET_UShort();
    d->EndSize     = GET_UShort();
    d->DeltaFormat = GET_UShort();

    FORGET_Frame();

    if ( d->StartSize > d->EndSize ||
         d->DeltaFormat == 0 || d->DeltaFormat > 3 )
      return TTO_Err_Invalid_SubTable;

    d->DeltaValue = NULL;

    count = ( ( d->EndSize - d->StartSize + 1 ) >>
                ( 4 - d->DeltaFormat ) ) + 1;

    if ( ALLOC_ARRAY( d->DeltaValue, count, FT_UShort ) )
      return error;

    if ( ACCESS_Frame( count * 2L ) )
    {
      FREE( d->DeltaValue );
      return error;
    }

    dv = d->DeltaValue;

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

    FORGET_Frame();

    return TT_Err_Ok;
  }


  void  Free_Device( TTO_Device*  d,
		     FT_Memory    memory )
  {
    FREE( d->DeltaValue );
  }


  /* Since we have the delta values stored in compressed form, we must
     uncompress it now.  To simplify the interface, the function always
     returns a meaningful value in `value'; the error is just for
     information.
                                 |                |
     format = 1: 0011223344556677|8899101112131415|...
                                 |                |
                      byte 1           byte 2

       00: (byte >> 14) & mask
       11: (byte >> 12) & mask
       ...

       mask = 0x0003
                                 |                |
     format = 2: 0000111122223333|4444555566667777|...
                                 |                |
                      byte 1           byte 2

       0000: (byte >> 12) & mask
       1111: (byte >>  8) & mask
       ...

       mask = 0x000F
                                 |                |
     format = 3: 0000000011111111|2222222233333333|...
                                 |                |
                      byte 1           byte 2

       00000000: (byte >> 8) & mask
       11111111: (byte >> 0) & mask
       ....

       mask = 0x00FF                                    */

  FT_Error  Get_Device( TTO_Device*  d,
                        FT_UShort    size,
                        FT_Short*    value )
  {
    FT_UShort  byte, bits, mask, f, s;


    f = d->DeltaFormat;

    if ( d->DeltaValue && size >= d->StartSize && size <= d->EndSize )
    {
      s    = size - d->StartSize;
      byte = d->DeltaValue[s >> ( 4 - f )];
      bits = byte >> ( 16 - ( ( s % ( 1 << ( 4 - f ) ) + 1 ) << f ) );
      mask = 0xFFFF >> ( 16 - ( 1 << f ) );

      *value = (FT_Short)( bits & mask );

      /* conversion to a signed value */

      if ( *value >= ( ( mask + 1 ) >> 1 ) )
        *value -= mask + 1;

      return TT_Err_Ok;
    }
    else
    {
      *value = 0;
      return TTO_Err_Not_Covered;
    }
  }


/* END */