harfbuzz-gsub.c

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

  for ( m = 0; m < n; m++ )
    Free_AlternateSet( &aset[m] );

  FREE( aset );

Fail2:
  _HB_OPEN_Free_Coverage( &as->Coverage );
  return error;
}


static void  Free_AlternateSubst( HB_GSUB_SubTable* st )
{
  HB_UShort          n, count;
  HB_AlternateSubst* as = &st->alternate;

  HB_AlternateSet*  aset;


  if ( as->AlternateSet )
  {
    count = as->AlternateSetCount;
    aset  = as->AlternateSet;

    for ( n = 0; n < count; n++ )
      Free_AlternateSet( &aset[n] );

    FREE( aset );
  }

  _HB_OPEN_Free_Coverage( &as->Coverage );
}


static HB_Error  Lookup_AlternateSubst( HB_GSUBHeader*    gsub,
					HB_GSUB_SubTable* st,
					HB_Buffer         buffer,
					HB_UShort          flags,
					HB_UShort          context_length,
					int                nesting_level )
{
  HB_Error          error;
  HB_UShort         index, value, alt_index, property;
  HB_AlternateSubst* as = &st->alternate;
  HB_GDEFHeader*     gdef = gsub->gdef;
  HB_AlternateSet  aset;

  HB_UNUSED(nesting_level);

  if ( context_length != 0xFFFF && context_length < 1 )
    return HB_Err_Not_Covered;

  if ( CHECK_Property( gdef, IN_CURITEM(), flags, &property ) )
    return error;

  error = _HB_OPEN_Coverage_Index( &as->Coverage, IN_CURGLYPH(), &index );
  if ( error )
    return error;

  aset = as->AlternateSet[index];

  /* we use a user-defined callback function to get the alternate index */

  if ( gsub->altfunc )
    alt_index = (gsub->altfunc)( buffer->out_pos, IN_CURGLYPH(),
				 aset.GlyphCount, aset.Alternate,
				 gsub->data );
  else
    alt_index = 0;

  value = aset.Alternate[alt_index];
  if ( REPLACE_Glyph( buffer, value, nesting_level ) )
    return error;

  if ( gdef && gdef->NewGlyphClasses )
  {
    /* we inherit the old glyph class to the substituted glyph */

    error = _HB_GDEF_Add_Glyph_Property( gdef, value, property );
    if ( error && error != HB_Err_Not_Covered )
      return error;
  }

  return HB_Err_Ok;
}


/* LookupType 4 */

/* Ligature */

static HB_Error  Load_Ligature( HB_Ligature*  l,
				HB_Stream      stream )
{
  HB_Error error;

  HB_UShort n, count;
  HB_UShort*  c;


  if ( ACCESS_Frame( 4L ) )
    return error;

  l->LigGlyph       = GET_UShort();
  l->ComponentCount = GET_UShort();

  FORGET_Frame();

  l->Component = NULL;

  count = l->ComponentCount - 1;      /* only ComponentCount - 1 elements */

  if ( ALLOC_ARRAY( l->Component, count, HB_UShort ) )
    return error;

  c = l->Component;

  if ( ACCESS_Frame( count * 2L ) )
  {
    FREE( c );
    return error;
  }

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

  FORGET_Frame();

  return HB_Err_Ok;
}


static void  Free_Ligature( HB_Ligature*  l )
{
  FREE( l->Component );
}


/* LigatureSet */

static HB_Error  Load_LigatureSet( HB_LigatureSet*  ls,
				   HB_Stream         stream )
{
  HB_Error error;

  HB_UShort      n = 0, m, count;
  HB_UInt       cur_offset, new_offset, base_offset;

  HB_Ligature*  l;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = ls->LigatureCount = GET_UShort();

  FORGET_Frame();

  ls->Ligature = NULL;

  if ( ALLOC_ARRAY( ls->Ligature, count, HB_Ligature ) )
    return error;

  l = ls->Ligature;

  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_Ligature( &l[n], stream ) ) != HB_Err_Ok )
      goto Fail;
    (void)FILE_Seek( cur_offset );
  }

  return HB_Err_Ok;

Fail:
  for ( m = 0; m < n; m++ )
    Free_Ligature( &l[m] );

  FREE( l );
  return error;
}


static void  Free_LigatureSet( HB_LigatureSet*  ls )
{
  HB_UShort      n, count;

  HB_Ligature*  l;


  if ( ls->Ligature )
  {
    count = ls->LigatureCount;
    l     = ls->Ligature;

    for ( n = 0; n < count; n++ )
      Free_Ligature( &l[n] );

    FREE( l );
  }
}


/* LigatureSubstFormat1 */

static HB_Error  Load_LigatureSubst( HB_GSUB_SubTable* st,
				     HB_Stream         stream )
{
  HB_Error error;
  HB_LigatureSubst*  ls = &st->ligature;

  HB_UShort         n = 0, m, count;
  HB_UInt          cur_offset, new_offset, base_offset;

  HB_LigatureSet*  lset;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 4L ) )
    return error;

  ls->SubstFormat = GET_UShort();             /* should be 1 */
  new_offset      = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_Coverage( &ls->Coverage, stream ) ) != HB_Err_Ok )
    return error;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 2L ) )
    goto Fail2;

  count = ls->LigatureSetCount = GET_UShort();

  FORGET_Frame();

  ls->LigatureSet = NULL;

  if ( ALLOC_ARRAY( ls->LigatureSet, count, HB_LigatureSet ) )
    goto Fail2;

  lset = ls->LigatureSet;

  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_LigatureSet( &lset[n], stream ) ) != HB_Err_Ok )
      goto Fail1;
    (void)FILE_Seek( cur_offset );
  }

  return HB_Err_Ok;

Fail1:
  for ( m = 0; m < n; m++ )
    Free_LigatureSet( &lset[m] );

  FREE( lset );

Fail2:
  _HB_OPEN_Free_Coverage( &ls->Coverage );
  return error;
}


static void  Free_LigatureSubst( HB_GSUB_SubTable* st )
{
  HB_UShort         n, count;
  HB_LigatureSubst*  ls = &st->ligature;

  HB_LigatureSet*  lset;


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

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

    FREE( lset );
  }

  _HB_OPEN_Free_Coverage( &ls->Coverage );
}


static HB_Error  Lookup_LigatureSubst( HB_GSUBHeader*    gsub,
				       HB_GSUB_SubTable* st,
				       HB_Buffer         buffer,
				       HB_UShort          flags,
				       HB_UShort          context_length,
				       int                nesting_level )
{
  HB_UShort      index, property;
  HB_Error       error;
  HB_UShort      numlig, i, j, is_mark, first_is_mark = FALSE;
  HB_UShort*     c;
  HB_LigatureSubst*  ls = &st->ligature;
  HB_GDEFHeader*     gdef = gsub->gdef;

  HB_Ligature*  lig;

  HB_UNUSED(nesting_level);

  if ( CHECK_Property( gdef, IN_CURITEM(), flags, &property ) )
    return error;

  if ( property == HB_GDEF_MARK || property & HB_LOOKUP_FLAG_IGNORE_SPECIAL_MARKS )
    first_is_mark = TRUE;

  error = _HB_OPEN_Coverage_Index( &ls->Coverage, IN_CURGLYPH(), &index );
  if ( error )
    return error;

  if ( index >= ls->LigatureSetCount )
     return ERR(HB_Err_Invalid_SubTable);

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

  for ( numlig = ls->LigatureSet[index].LigatureCount;
	numlig;
	numlig--, lig++ )
  {
    if ( buffer->in_pos + lig->ComponentCount > buffer->in_length )
      goto next_ligature;               /* Not enough glyphs in input */

    c    = lig->Component;

    is_mark = first_is_mark;

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

    for ( i = 1, j = buffer->in_pos + 1; i < lig->ComponentCount; i++, j++ )
    {
      while ( CHECK_Property( gdef, IN_ITEM( j ), flags, &property ) )
      {
	if ( error && error != HB_Err_Not_Covered )
	  return error;

	if ( j + lig->ComponentCount - i == (HB_Int)buffer->in_length )
	  goto next_ligature;
	j++;
      }

      if ( !( property == HB_GDEF_MARK || property & HB_LOOKUP_FLAG_IGNORE_SPECIAL_MARKS ) )
	is_mark = FALSE;

      if ( IN_GLYPH( j ) != c[i - 1] )
	goto next_ligature;
    }

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

      error = _HB_GDEF_Add_Glyph_Property( gdef, lig->LigGlyph,
				  is_mark ? HB_GDEF_MARK : HB_GDEF_LIGATURE );
      if ( error && error != HB_Err_Not_Covered )
	return error;
    }

    if ( j == buffer->in_pos + i ) /* No input glyphs skipped */
    {
      /* We don't use a new ligature ID if there are no skipped
	 glyphs and the ligature already has an ID.             */

      if ( IN_LIGID( buffer->in_pos ) )
      {
	if ( ADD_String( buffer, i, 1, &lig->LigGlyph,
			0xFFFF, 0xFFFF ) )
	  return error;
      }
      else
      {
	HB_UShort ligID = _hb_buffer_allocate_ligid( buffer );
	if ( ADD_String( buffer, i, 1, &lig->LigGlyph,
			0xFFFF, ligID ) )
	  return error;
      }
    }
    else
    {
      HB_UShort ligID = _hb_buffer_allocate_ligid( buffer );
      if ( ADD_Glyph( buffer, lig->LigGlyph, 0xFFFF, ligID ) )
	return error;

      /* 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_CURITEM(),
				flags, &property ) )
	  if ( ADD_Glyph( buffer, IN_CURGLYPH(), i, ligID ) )
	    return error;

	(buffer->in_pos)++;
      }
    }

    return HB_Err_Ok;

  next_ligature:
    ;
  }

  return HB_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 HB_Error  Do_ContextSubst( HB_GSUBHeader*        gsub,
				  HB_UShort              GlyphCount,
				  HB_UShort              SubstCount,
				  HB_SubstLookupRecord* subst,
				  HB_Buffer             buffer,
				  int                    nesting_level )
{
  HB_Error  error;
  HB_UInt i, old_pos;


  i = 0;

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

      /* Do a substitution */

      error = GSUB_Do_Glyph_Lookup( gsub, subst->LookupListIndex, buffer,
				    GlyphCount, nesting_level );

      subst++;
      SubstCount--;
      i += buffer->in_pos - old_pos;

      if ( error == HB_Err_Not_Covered )
      {
	if ( COPY_Glyph( buffer ) )
	  return error;
	i++;
      }
      else if ( error )
	return error;
    }
    else
    {
      /* No substitution for this index */

      if ( COPY_Glyph( buffer ) )
	return error;
      i++;
    }
  }

  return HB_Err_Ok;
}


/* LookupType 5 */

/* SubRule */

static HB_Error  Load_SubRule( HB_SubRule*  sr,
			       HB_Stream     stream )
{
  HB_Error error;

  HB_UShort               n, count;
  HB_UShort*              i;

  HB_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, HB_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, HB_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 HB_Err_Ok;

Fail1:
  FREE( slr );

Fail2:
  FREE( i );
  return error;
}


static void  Free_SubRule( HB_SubRule*  sr )
{
  FREE( sr->SubstLookupRecord );
  FREE( sr->Input );
}


/* SubRuleSet */

static HB_Error  Load_SubRuleSet( HB_SubRuleSet*  srs,
				  HB_Stream        stream )
{
  HB_Error error;

  HB_UShort     n = 0, m, count;
  HB_UInt      cur_offset, new_offset, base_offset;

  HB_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, HB_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 ) ) != HB_Err_Ok )
      goto Fail;
    (void)FILE_Seek( cur_offset );
  }

  return HB_Err_Ok;

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

  FREE( sr );
  return error;
}


static void  Free_SubRuleSet( HB_SubRuleSet*  srs )
{
  HB_UShort     n, count;