harfbuzz-open.c

Pango is a library for layout and rendering of text, with an emphasis on internationalization. Pang

  HB_UShort         n, count;

  HB_RangeRecord*  rr;


  if ( ACCESS_Frame( 2L ) )
    return error;

  count = cf2->RangeCount = GET_UShort();

  FORGET_Frame();

  cf2->RangeRecord = NULL;

  if ( ALLOC_ARRAY( cf2->RangeRecord, count, HB_RangeRecord ) )
    return error;

  rr = cf2->RangeRecord;

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

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

    /* sanity check; we are limited to 16bit integers */
    if ( rr[n].Start > rr[n].End ||
	 ( rr[n].End - rr[n].Start + (long)rr[n].StartCoverageIndex ) >=
	   0x10000L )
    {
      error = ERR(HB_Err_Invalid_SubTable);
      goto Fail;
    }
  }

  FORGET_Frame();

  return HB_Err_Ok;

Fail:
  FREE( cf2->RangeRecord );
  return error;
}


static void  Free_Coverage2( HB_CoverageFormat2*  cf2 )
{
  FREE( cf2->RangeRecord );
}


HB_INTERNAL HB_Error
_HB_OPEN_Load_Coverage( HB_Coverage* c,
			HB_Stream    stream )
{
  HB_Error   error;

  if ( ACCESS_Frame( 2L ) )
    return error;

  c->CoverageFormat = GET_UShort();

  FORGET_Frame();

  switch ( c->CoverageFormat )
  {
  case 1:  return Load_Coverage1( &c->cf.cf1, stream );
  case 2:  return Load_Coverage2( &c->cf.cf2, stream );
  default: return ERR(HB_Err_Invalid_SubTable_Format);
  }

  return HB_Err_Ok;               /* never reached */
}


HB_INTERNAL void
_HB_OPEN_Free_Coverage( HB_Coverage* c )
{
  switch ( c->CoverageFormat )
  {
  case 1:  Free_Coverage1( &c->cf.cf1 ); break;
  case 2:  Free_Coverage2( &c->cf.cf2 ); break;
  default:					 break;
  }
}


static HB_Error  Coverage_Index1( HB_CoverageFormat1*  cf1,
				  HB_UShort             glyphID,
				  HB_UShort*            index )
{
  HB_UShort min, max, new_min, new_max, middle;

  HB_UShort*  array = cf1->GlyphArray;


  /* binary search */

  if ( cf1->GlyphCount == 0 )
    return HB_Err_Not_Covered;

  new_min = 0;
  new_max = cf1->GlyphCount - 1;

  do
  {
    min = new_min;
    max = new_max;

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

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

    if ( glyphID == array[middle] )
    {
      *index = middle;
      return HB_Err_Ok;
    }
    else if ( glyphID < array[middle] )
    {
      if ( middle == min )
	break;
      new_max = middle - 1;
    }
    else
    {
      if ( middle == max )
	break;
      new_min = middle + 1;
    }
  } while ( min < max );

  return HB_Err_Not_Covered;
}


static HB_Error  Coverage_Index2( HB_CoverageFormat2*  cf2,
				  HB_UShort             glyphID,
				  HB_UShort*            index )
{
  HB_UShort         min, max, new_min, new_max, middle;

  HB_RangeRecord*  rr = cf2->RangeRecord;


  /* binary search */

  if ( cf2->RangeCount == 0 )
    return HB_Err_Not_Covered;

  new_min = 0;
  new_max = cf2->RangeCount - 1;

  do
  {
    min = new_min;
    max = new_max;

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

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

    if ( glyphID >= rr[middle].Start && glyphID <= rr[middle].End )
    {
      *index = rr[middle].StartCoverageIndex + glyphID - rr[middle].Start;
      return HB_Err_Ok;
    }
    else if ( glyphID < rr[middle].Start )
    {
      if ( middle == min )
	break;
      new_max = middle - 1;
    }
    else
    {
      if ( middle == max )
	break;
      new_min = middle + 1;
    }
  } while ( min < max );

  return HB_Err_Not_Covered;
}


HB_INTERNAL HB_Error
_HB_OPEN_Coverage_Index( HB_Coverage* c,
			 HB_UShort    glyphID,
			 HB_UShort*   index )
{
  switch ( c->CoverageFormat )
  {
  case 1:  return Coverage_Index1( &c->cf.cf1, glyphID, index );
  case 2:  return Coverage_Index2( &c->cf.cf2, glyphID, index );
  default: return ERR(HB_Err_Invalid_SubTable_Format);
  }

  return HB_Err_Ok;               /* never reached */
}



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


/* ClassDefFormat1 */

static HB_Error  Load_ClassDef1( HB_ClassDefinition*  cd,
				 HB_UShort             limit,
				 HB_Stream             stream )
{
  HB_Error   error;

  HB_UShort             n, count;

  HB_UShort*            cva;
  HB_Bool*              d;

  HB_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 ERR(HB_Err_Invalid_SubTable);

  cdf1->ClassValueArray = NULL;

  if ( ALLOC_ARRAY( cdf1->ClassValueArray, count, HB_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 = ERR(HB_Err_Invalid_SubTable);
      goto Fail;
    }
    d[cva[n]] = TRUE;
  }

  FORGET_Frame();

  return HB_Err_Ok;

Fail:
  FREE( cva );

  return error;
}


static void  Free_ClassDef1( HB_ClassDefFormat1*  cdf1 )
{
  FREE( cdf1->ClassValueArray );
}


/* ClassDefFormat2 */

static HB_Error  Load_ClassDef2( HB_ClassDefinition*  cd,
				 HB_UShort             limit,
				 HB_Stream             stream )
{
  HB_Error   error;

  HB_UShort              n, count;

  HB_ClassRangeRecord*  crr;
  HB_Bool*               d;

  HB_ClassDefFormat2*   cdf2;


  cdf2 = &cd->cd.cd2;

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = GET_UShort();
  cdf2->ClassRangeCount = 0; /* zero for now.  we fill with the number of good entries later */

  FORGET_Frame();

  cdf2->ClassRangeRecord = NULL;

  if ( ALLOC_ARRAY( cdf2->ClassRangeRecord, count, HB_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 )
    {
      /* XXX
       * Corrupt entry.  Skip it.
       * This is hit by Nafees Nastaliq font for example
       */
       n--;
       count--;
    }
    else
      d[crr[n].Class] = TRUE;
  }

  FORGET_Frame();

  cdf2->ClassRangeCount = count;

  return HB_Err_Ok;

Fail:
  FREE( crr );

  return error;
}


static void  Free_ClassDef2( HB_ClassDefFormat2*  cdf2 )
{
  FREE( cdf2->ClassRangeRecord );
}


/* ClassDefinition */

HB_INTERNAL HB_Error
_HB_OPEN_Load_ClassDefinition( HB_ClassDefinition* cd,
			       HB_UShort           limit,
			       HB_Stream           stream )
{
  HB_Error   error;

  if ( ALLOC_ARRAY( cd->Defined, limit, HB_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 = ERR(HB_Err_Invalid_SubTable_Format);	break;
  }

  if ( error )
    goto Fail;

  cd->loaded = TRUE;

  return HB_Err_Ok;

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


static HB_Error
_HB_OPEN_Load_EmptyClassDefinition( HB_ClassDefinition*  cd )
{
  HB_Error   error;

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

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

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

  return HB_Err_Ok;

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

HB_INTERNAL HB_Error
_HB_OPEN_Load_EmptyOrClassDefinition( HB_ClassDefinition* cd,
				      HB_UShort           limit,
				      HB_UInt            class_offset,
				      HB_UInt            base_offset,
				      HB_Stream           stream )
{
  HB_Error error;
  HB_UInt               cur_offset;

  cur_offset = FILE_Pos();

  if ( class_offset )
    {
      if ( !FILE_Seek( class_offset + base_offset ) )
	error = _HB_OPEN_Load_ClassDefinition( cd, limit, stream );
    }
  else
     error = _HB_OPEN_Load_EmptyClassDefinition ( cd );

  if (error == HB_Err_Ok)
    (void)FILE_Seek( cur_offset ); /* Changes error as a side-effect */

  return error;
}

HB_INTERNAL void
_HB_OPEN_Free_ClassDefinition( HB_ClassDefinition*  cd )
{
  if ( !cd->loaded )
    return;

  FREE( cd->Defined );

  switch ( cd->ClassFormat )
  {
  case 1:  Free_ClassDef1( &cd->cd.cd1 ); break;
  case 2:  Free_ClassDef2( &cd->cd.cd2 ); break;
  default:				  break;
  }
}


static HB_Error  Get_Class1( HB_ClassDefFormat1*  cdf1,
			     HB_UShort             glyphID,
			     HB_UShort*            klass,
			     HB_UShort*            index )
{
  HB_UShort*  cva = cdf1->ClassValueArray;


  if ( index )
    *index = 0;

  if ( glyphID >= cdf1->StartGlyph &&
       glyphID < cdf1->StartGlyph + cdf1->GlyphCount )
  {
    *klass = cva[glyphID - cdf1->StartGlyph];
    return HB_Err_Ok;
  }
  else
  {
    *klass = 0;
    return HB_Err_Not_Covered;
  }
}


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

static HB_Error  Get_Class2( HB_ClassDefFormat2*  cdf2,
			     HB_UShort             glyphID,
			     HB_UShort*            klass,
			     HB_UShort*            index )
{
  HB_Error               error = HB_Err_Ok;
  HB_UShort              min, max, new_min, new_max, middle;

  HB_ClassRangeRecord*  crr = cdf2->ClassRangeRecord;


  /* binary search */

  if ( cdf2->ClassRangeCount == 0 )
    {
      *klass = 0;
      if ( index )
	*index = 0;
      
      return HB_Err_Not_Covered;
    }

  new_min = 0;
  new_max = cdf2->ClassRangeCount - 1;

  do
  {
    min = new_min;
    max = new_max;

    /* 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;
      error  = HB_Err_Ok;
      break;
    }
    else if ( glyphID < crr[middle].Start )
    {
      if ( middle == min )
      {
	*klass = 0;
	error  = HB_Err_Not_Covered;
	break;
      }
      new_max = middle - 1;
    }
    else
    {
      if ( middle == max )
      {
	*klass = 0;
	error  = HB_Err_Not_Covered;
	break;
      }
      new_min = middle + 1;
    }
  } while ( min < max );

  if ( index )
    *index = middle;

  return error;
}


HB_INTERNAL HB_Error
_HB_OPEN_Get_Class( HB_ClassDefinition* cd,
		    HB_UShort           glyphID,
		    HB_UShort*          klass,
		    HB_UShort*          index )
{
  switch ( cd->ClassFormat )
  {
  case 1:  return Get_Class1( &cd->cd.cd1, glyphID, klass, index );
  case 2:  return Get_Class2( &cd->cd.cd2, glyphID, klass, index );
  default: return ERR(HB_Err_Invalid_SubTable_Format);
  }

  return HB_Err_Ok;               /* never reached */
}



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


HB_INTERNAL HB_Error
_HB_OPEN_Load_Device( HB_Device* d,
		      HB_Stream  stream )
{
  HB_Error   error;

  HB_UShort   n, count;

  HB_UShort*  dv;


  if ( ACCESS_Frame( 6L ) )
    return error;

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

  FORGET_Frame();

  d->DeltaValue = NULL;

  if ( d->StartSize > d->EndSize ||
       d->DeltaFormat == 0 || d->DeltaFormat > 3 )
    {
      /* XXX
       * I've seen fontforge generate DeltaFormat == 0.
       * Just return Ok and let the NULL DeltaValue disable
       * this table.
       */
      return HB_Err_Ok;
    }

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

  if ( ALLOC_ARRAY( d->DeltaValue, count, HB_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 HB_Err_Ok;
}


HB_INTERNAL void
_HB_OPEN_Free_Device( HB_Device* d )
{
  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                                    */

HB_INTERNAL HB_Error
_HB_OPEN_Get_Device( HB_Device* d,
		     HB_UShort  size,
		     HB_Short*  value )
{
  HB_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 = (HB_Short)( bits & mask );

    /* conversion to a signed value */

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

    return HB_Err_Ok;
  }
  else
  {
    *value = 0;
    return HB_Err_Not_Covered;
  }
}


/* END */