src/harfbuzz-gpos.c

/*
 * Copyright (C) 1998-2004  David Turner and Werner Lemberg
 * Copyright (C) 2006  Behdad Esfahbod
 * Copyright (C) 2007  Red Hat, Inc.
 *
 * This is part of HarfBuzz, an OpenType Layout engine library.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 *
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 *
 * Red Hat Author(s): Behdad Esfahbod
 */

#include "harfbuzz-impl.h"
#include "harfbuzz-gpos-private.h"
#include "harfbuzz-open-private.h"
#include "harfbuzz-gdef-private.h"

struct  GPOS_Instance_
{
  HB_GPOSHeader*  gpos;
  HB_Font          font;
  HB_Bool          dvi;
  HB_UShort        load_flags;  /* how the glyph should be loaded */
  HB_Bool          r2l;

  HB_UShort        last;        /* the last valid glyph -- used
				   with cursive positioning     */
  HB_Fixed           anchor_x;    /* the coordinates of the anchor point */
  HB_Fixed           anchor_y;    /* of the last valid glyph             */
};

typedef struct GPOS_Instance_  GPOS_Instance;


static HB_Error  GPOS_Do_Glyph_Lookup( GPOS_Instance*    gpi,
				       HB_UShort         lookup_index,
				       HB_Buffer        buffer,
				       HB_UShort         context_length,
				       int               nesting_level );



/* the client application must replace this with something more
   meaningful if multiple master fonts are to be supported.     */

static HB_Error  default_mmfunc( HB_Font      font,
				 HB_UShort    metric_id,
				 HB_Fixed*      metric_value,
				 void*        data )
{
  HB_UNUSED(font);
  HB_UNUSED(metric_id);
  HB_UNUSED(metric_value);
  HB_UNUSED(data);
  return ERR(HB_Err_Not_Covered); /* ERR() call intended */
}



HB_Error  HB_Load_GPOS_Table( HB_Font          font,
			      HB_GPOSHeader** retptr,
			      hb_ot_layout_t    *layout )
{
  HB_UInt         cur_offset, new_offset, base_offset;

  HB_GPOSHeader*  gpos;

  HB_Stream  stream = font->stream;
  HB_Error   error;


  if ( !retptr || !layout )
    return ERR(HB_Err_Invalid_Argument);

  if ( GOTO_Table( TTAG_GPOS ) )
    return error;

  base_offset = FILE_Pos();

  if ( ALLOC ( gpos, sizeof( *gpos ) ) )
    return error;

  gpos->gfunc = (HB_GlyphFunction) FT_Load_Glyph;
  gpos->mmfunc = default_mmfunc;

  /* skip version */

  if ( FILE_Seek( base_offset + 4L ) ||
       ACCESS_Frame( 2L ) )
    goto Fail4;

  new_offset = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_ScriptList( &gpos->ScriptList,
				  stream ) ) != HB_Err_Ok )
    goto Fail4;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 2L ) )
    goto Fail3;

  new_offset = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_FeatureList( &gpos->FeatureList,
				   stream ) ) != HB_Err_Ok )
    goto Fail3;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 2L ) )
    goto Fail2;

  new_offset = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_LookupList( &gpos->LookupList,
				  stream, HB_Type_GPOS ) ) != HB_Err_Ok )
    goto Fail2;

  gpos->layout = layout;      /* can be NULL */

  *retptr = gpos;

  return HB_Err_Ok;

Fail2:
  _HB_OPEN_Free_FeatureList( &gpos->FeatureList );

Fail3:
  _HB_OPEN_Free_ScriptList( &gpos->ScriptList );

Fail4:
  FREE( gpos );

  return error;
}


HB_Error  HB_Done_GPOS_Table( HB_GPOSHeader* gpos )
{
  _HB_OPEN_Free_LookupList( &gpos->LookupList, HB_Type_GPOS );
  _HB_OPEN_Free_FeatureList( &gpos->FeatureList );
  _HB_OPEN_Free_ScriptList( &gpos->ScriptList );

  FREE( gpos );

  return HB_Err_Ok;
}


/*****************************
 * SubTable related functions
 *****************************/

/* shared tables */

/* ValueRecord */

/* There is a subtle difference in the specs between a `table' and a
   `record' -- offsets for device tables in ValueRecords are taken from
   the parent table and not the parent record.                          */

static HB_Error  Load_ValueRecord( HB_ValueRecord*  vr,
				   HB_UShort         format,
				   HB_UInt          base_offset,
				   HB_Stream         stream )
{
  HB_Error  error;

  HB_UInt cur_offset, new_offset;


  if ( format & HB_GPOS_FORMAT_HAVE_X_PLACEMENT )
  {
    if ( ACCESS_Frame( 2L ) )
      return error;

    vr->XPlacement = GET_Short();

    FORGET_Frame();
  }
  else
    vr->XPlacement = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_Y_PLACEMENT )
  {
    if ( ACCESS_Frame( 2L ) )
      return error;

    vr->YPlacement = GET_Short();

    FORGET_Frame();
  }
  else
    vr->YPlacement = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_X_ADVANCE )
  {
    if ( ACCESS_Frame( 2L ) )
      return error;

    vr->XAdvance = GET_Short();

    FORGET_Frame();
  }
  else
    vr->XAdvance = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_Y_ADVANCE )
  {
    if ( ACCESS_Frame( 2L ) )
      return error;

    vr->YAdvance = GET_Short();

    FORGET_Frame();
  }
  else
    vr->YAdvance = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_X_PLACEMENT_DEVICE )
  {
    if ( ACCESS_Frame( 2L ) )
      return error;

    new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = _HB_OPEN_Load_Device( &vr->XPlacementDevice,
				  stream ) ) != HB_Err_Ok )
	return error;
      (void)FILE_Seek( cur_offset );
    }
    else
      goto empty1;
  }
  else
  {
  empty1:
    vr->XPlacementDevice.StartSize  = 0;
    vr->XPlacementDevice.EndSize    = 0;
    vr->XPlacementDevice.DeltaValue = NULL;
  }

  if ( format & HB_GPOS_FORMAT_HAVE_Y_PLACEMENT_DEVICE )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail3;

    new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = _HB_OPEN_Load_Device( &vr->YPlacementDevice,
				  stream ) ) != HB_Err_Ok )
	goto Fail3;
      (void)FILE_Seek( cur_offset );
    }
    else
      goto empty2;
  }
  else
  {
  empty2:
    vr->YPlacementDevice.StartSize  = 0;
    vr->YPlacementDevice.EndSize    = 0;
    vr->YPlacementDevice.DeltaValue = NULL;
  }

  if ( format & HB_GPOS_FORMAT_HAVE_X_ADVANCE_DEVICE )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail2;

    new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = _HB_OPEN_Load_Device( &vr->XAdvanceDevice,
				  stream ) ) != HB_Err_Ok )
	goto Fail2;
      (void)FILE_Seek( cur_offset );
    }
    else
      goto empty3;
  }
  else
  {
  empty3:
    vr->XAdvanceDevice.StartSize  = 0;
    vr->XAdvanceDevice.EndSize    = 0;
    vr->XAdvanceDevice.DeltaValue = NULL;
  }

  if ( format & HB_GPOS_FORMAT_HAVE_Y_ADVANCE_DEVICE )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail1;

    new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = _HB_OPEN_Load_Device( &vr->YAdvanceDevice,
				  stream ) ) != HB_Err_Ok )
	goto Fail1;
      (void)FILE_Seek( cur_offset );
    }
    else
      goto empty4;
  }
  else
  {
  empty4:
    vr->YAdvanceDevice.StartSize  = 0;
    vr->YAdvanceDevice.EndSize    = 0;
    vr->YAdvanceDevice.DeltaValue = NULL;
  }

  if ( format & HB_GPOS_FORMAT_HAVE_X_ID_PLACEMENT )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail1;

    vr->XIdPlacement = GET_UShort();

    FORGET_Frame();
  }
  else
    vr->XIdPlacement = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_Y_ID_PLACEMENT )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail1;

    vr->YIdPlacement = GET_UShort();

    FORGET_Frame();
  }
  else
    vr->YIdPlacement = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_X_ID_ADVANCE )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail1;

    vr->XIdAdvance = GET_UShort();

    FORGET_Frame();
  }
  else
    vr->XIdAdvance = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_Y_ID_ADVANCE )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail1;

    vr->YIdAdvance = GET_UShort();

    FORGET_Frame();
  }
  else
    vr->YIdAdvance = 0;

  return HB_Err_Ok;

Fail1:
  _HB_OPEN_Free_Device( &vr->YAdvanceDevice );

Fail2:
  _HB_OPEN_Free_Device( &vr->XAdvanceDevice );

Fail3:
  _HB_OPEN_Free_Device( &vr->YPlacementDevice );
  return error;
}


static void  Free_ValueRecord( HB_ValueRecord*  vr,
			       HB_UShort         format )
{
  if ( format & HB_GPOS_FORMAT_HAVE_Y_ADVANCE_DEVICE )
    _HB_OPEN_Free_Device( &vr->YAdvanceDevice );
  if ( format & HB_GPOS_FORMAT_HAVE_X_ADVANCE_DEVICE )
    _HB_OPEN_Free_Device( &vr->XAdvanceDevice );
  if ( format & HB_GPOS_FORMAT_HAVE_Y_PLACEMENT_DEVICE )
    _HB_OPEN_Free_Device( &vr->YPlacementDevice );
  if ( format & HB_GPOS_FORMAT_HAVE_X_PLACEMENT_DEVICE )
    _HB_OPEN_Free_Device( &vr->XPlacementDevice );
}


static HB_Error  Get_ValueRecord( GPOS_Instance*    gpi,
				  HB_ValueRecord*  vr,
				  HB_UShort         format,
				  HB_Position      gd )
{
  HB_Fixed           value;
  HB_Short         pixel_value;
  HB_Error         error = HB_Err_Ok;
  HB_GPOSHeader*  gpos = gpi->gpos;

  HB_UShort  x_ppem, y_ppem;
  HB_16Dot16   x_scale, y_scale;


  if ( !format )
    return HB_Err_Ok;

  x_ppem  = gpi->font->size->metrics.x_ppem;
  y_ppem  = gpi->font->size->metrics.y_ppem;
  x_scale = gpi->font->size->metrics.x_scale;
  y_scale = gpi->font->size->metrics.y_scale;

  /* design units -> fractional pixel */

  if ( format & HB_GPOS_FORMAT_HAVE_X_PLACEMENT )
    gd->x_pos += x_scale * vr->XPlacement / 0x10000;
  if ( format & HB_GPOS_FORMAT_HAVE_Y_PLACEMENT )
    gd->y_pos += y_scale * vr->YPlacement / 0x10000;
  if ( format & HB_GPOS_FORMAT_HAVE_X_ADVANCE )
    gd->x_advance += x_scale * vr->XAdvance / 0x10000;
  if ( format & HB_GPOS_FORMAT_HAVE_Y_ADVANCE )
    gd->y_advance += y_scale * vr->YAdvance / 0x10000;

  if ( !gpi->dvi )
  {
    /* pixel -> fractional pixel */

    if ( format & HB_GPOS_FORMAT_HAVE_X_PLACEMENT_DEVICE )
    {
      _HB_OPEN_Get_Device( &vr->XPlacementDevice, x_ppem, &pixel_value );
      gd->x_pos += pixel_value << 6;
    }
    if ( format & HB_GPOS_FORMAT_HAVE_Y_PLACEMENT_DEVICE )
    {
      _HB_OPEN_Get_Device( &vr->YPlacementDevice, y_ppem, &pixel_value );
      gd->y_pos += pixel_value << 6;
    }
    if ( format & HB_GPOS_FORMAT_HAVE_X_ADVANCE_DEVICE )
    {
      _HB_OPEN_Get_Device( &vr->XAdvanceDevice, x_ppem, &pixel_value );
      gd->x_advance += pixel_value << 6;
    }
    if ( format & HB_GPOS_FORMAT_HAVE_Y_ADVANCE_DEVICE )
    {
      _HB_OPEN_Get_Device( &vr->YAdvanceDevice, y_ppem, &pixel_value );
      gd->y_advance += pixel_value << 6;
    }
  }

  /* values returned from mmfunc() are already in fractional pixels */

  if ( format & HB_GPOS_FORMAT_HAVE_X_ID_PLACEMENT )
  {
    error = (gpos->mmfunc)( gpi->font, vr->XIdPlacement,
			    &value, gpos->data );
    if ( error )
      return error;
    gd->x_pos += value;
  }
  if ( format & HB_GPOS_FORMAT_HAVE_Y_ID_PLACEMENT )
  {
    error = (gpos->mmfunc)( gpi->font, vr->YIdPlacement,
			    &value, gpos->data );
    if ( error )
      return error;
    gd->y_pos += value;
  }
  if ( format & HB_GPOS_FORMAT_HAVE_X_ID_ADVANCE )
  {
    error = (gpos->mmfunc)( gpi->font, vr->XIdAdvance,
			    &value, gpos->data );
    if ( error )
      return error;
    gd->x_advance += value;
  }
  if ( format & HB_GPOS_FORMAT_HAVE_Y_ID_ADVANCE )
  {
    error = (gpos->mmfunc)( gpi->font, vr->YIdAdvance,
			    &value, gpos->data );
    if ( error )
      return error;
    gd->y_advance += value;
  }

  return error;
}


/* AnchorFormat1 */
/* AnchorFormat2 */
/* AnchorFormat3 */
/* AnchorFormat4 */

static HB_Error  Load_Anchor( HB_Anchor*  an,
			      HB_Stream    stream )
{
  HB_Error  error;

  HB_UInt cur_offset, new_offset, base_offset;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  an->PosFormat = GET_UShort();

  FORGET_Frame();

  switch ( an->PosFormat )
  {
  case 1:
    if ( ACCESS_Frame( 4L ) )
      return error;

    an->af.af1.XCoordinate = GET_Short();
    an->af.af1.YCoordinate = GET_Short();

    FORGET_Frame();
    break;

  case 2:
    if ( ACCESS_Frame( 6L ) )
      return error;

    an->af.af2.XCoordinate = GET_Short();
    an->af.af2.YCoordinate = GET_Short();
    an->af.af2.AnchorPoint = GET_UShort();

    FORGET_Frame();
    break;

  case 3:
    if ( ACCESS_Frame( 6L ) )
      return error;

    an->af.af3.XCoordinate = GET_Short();
    an->af.af3.YCoordinate = GET_Short();

    new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = _HB_OPEN_Load_Device( &an->af.af3.XDeviceTable,
				  stream ) ) != HB_Err_Ok )
	return error;
      (void)FILE_Seek( cur_offset );
    }
    else
    {
      an->af.af3.XDeviceTable.StartSize  = 0;
      an->af.af3.XDeviceTable.EndSize    = 0;
      an->af.af3.XDeviceTable.DeltaValue = NULL;
    }

    if ( ACCESS_Frame( 2L ) )
      goto Fail;

    new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = _HB_OPEN_Load_Device( &an->af.af3.YDeviceTable,
				  stream ) ) != HB_Err_Ok )
	goto Fail;
      (void)FILE_Seek( cur_offset );
    }
    else
    {
      an->af.af3.YDeviceTable.StartSize  = 0;
      an->af.af3.YDeviceTable.EndSize    = 0;
      an->af.af3.YDeviceTable.DeltaValue = NULL;
    }
    break;

  case 4:
    if ( ACCESS_Frame( 4L ) )
      return error;

    an->af.af4.XIdAnchor = GET_UShort();
    an->af.af4.YIdAnchor = GET_UShort();

    FORGET_Frame();
    break;

  default:
    return ERR(HB_Err_Invalid_SubTable_Format);
  }

  return HB_Err_Ok;

Fail:
  _HB_OPEN_Free_Device( &an->af.af3.XDeviceTable );
  return error;
}


static void  Free_Anchor( HB_Anchor*  an )
{
  if ( an->PosFormat == 3 )
  {
    _HB_OPEN_Free_Device( &an->af.af3.YDeviceTable );
    _HB_OPEN_Free_Device( &an->af.af3.XDeviceTable );
  }
}


static HB_Error  Get_Anchor( GPOS_Instance*   gpi,
			     HB_Anchor*      an,
			     HB_UShort        glyph_index,
			     HB_Fixed*          x_value,
			     HB_Fixed*          y_value )
{
  HB_Error  error = HB_Err_Ok;

  FT_Outline       outline;
  HB_GPOSHeader*  gpos = gpi->gpos;
  HB_UShort        ap;

  HB_Short         pixel_value;
  HB_UShort        load_flags;

  HB_UShort        x_ppem, y_ppem;
  HB_16Dot16         x_scale, y_scale;


  x_ppem  = gpi->font->size->metrics.x_ppem;
  y_ppem  = gpi->font->size->metrics.y_ppem;
  x_scale = gpi->font->size->metrics.x_scale;
  y_scale = gpi->font->size->metrics.y_scale;

  switch ( an->PosFormat )
  {
  case 0:
    /* The special case of an empty AnchorTable */
  default:

    return HB_Err_Not_Covered;

  case 1:
    *x_value = x_scale * an->af.af1.XCoordinate / 0x10000;
    *y_value = y_scale * an->af.af1.YCoordinate / 0x10000;
    break;

  case 2:
    /* glyphs must be scaled */

    load_flags = gpi->load_flags & ~FT_LOAD_NO_SCALE;

    if ( !gpi->dvi )
    {
      error = (gpos->gfunc)( gpi->font, glyph_index, load_flags );
      if ( error )
	return error;

      if ( gpi->font->glyph->format != ft_glyph_format_outline )
	return ERR(HB_Err_Invalid_SubTable);

      ap = an->af.af2.AnchorPoint;

      outline = gpi->font->glyph->outline;

      /* if n_points is set to zero, we use the design coordinate value pair.
       * This can happen e.g. for sbit glyphs. */ 
      if ( !outline.n_points )
	goto no_contour_point;

      if ( ap >= outline.n_points )
	return ERR(HB_Err_Invalid_SubTable);

      *x_value = outline.points[ap].x;
      *y_value = outline.points[ap].y;
    }
    else
    {
    no_contour_point:
      *x_value = x_scale * an->af.af3.XCoordinate / 0x10000;
      *y_value = y_scale * an->af.af3.YCoordinate / 0x10000;
    }
    break;

  case 3:
    if ( !gpi->dvi )
    {
      _HB_OPEN_Get_Device( &an->af.af3.XDeviceTable, x_ppem, &pixel_value );
      *x_value = pixel_value << 6;
      _HB_OPEN_Get_Device( &an->af.af3.YDeviceTable, y_ppem, &pixel_value );
      *y_value = pixel_value << 6;
    }
    else
      *x_value = *y_value = 0;

    *x_value += x_scale * an->af.af3.XCoordinate / 0x10000;
    *y_value += y_scale * an->af.af3.YCoordinate / 0x10000;
    break;

  case 4:
    error = (gpos->mmfunc)( gpi->font, an->af.af4.XIdAnchor,
			    x_value, gpos->data );
    if ( error )
      return error;

    error = (gpos->mmfunc)( gpi->font, an->af.af4.YIdAnchor,
			    y_value, gpos->data );
    if ( error )
      return error;
    break;
  }

  return error;
}


/* MarkArray */

static HB_Error  Load_MarkArray ( HB_MarkArray*  ma,
				  HB_Stream       stream )
{
  HB_Error  error;

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

  HB_MarkRecord*  mr;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = ma->MarkCount = GET_UShort();

  FORGET_Frame();

  ma->MarkRecord = NULL;

  if ( ALLOC_ARRAY( ma->MarkRecord, count, HB_MarkRecord ) )
    return error;

  mr = ma->MarkRecord;

  for ( n = 0; n < count; n++ )
  {
    if ( ACCESS_Frame( 4L ) )
      goto Fail;

    mr[n].Class = GET_UShort();
    new_offset  = GET_UShort() + base_offset;

    FORGET_Frame();

    cur_offset = FILE_Pos();
    if ( FILE_Seek( new_offset ) ||
	 ( error = Load_Anchor( &mr[n].MarkAnchor, stream ) ) != HB_Err_Ok )
      goto Fail;
    (void)FILE_Seek( cur_offset );
  }

  return HB_Err_Ok;

Fail:
  for ( m = 0; m < n; m++ )
    Free_Anchor( &mr[m].MarkAnchor );

  FREE( mr );
  return error;
}


static void  Free_MarkArray( HB_MarkArray*  ma )
{
  HB_UShort        n, count;

  HB_MarkRecord*  mr;


  if ( ma->MarkRecord )
  {
    count = ma->MarkCount;
    mr    = ma->MarkRecord;

    for ( n = 0; n < count; n++ )
      Free_Anchor( &mr[n].MarkAnchor );

    FREE( mr );
  }
}


/* LookupType 1 */

/* SinglePosFormat1 */
/* SinglePosFormat2 */

static HB_Error  Load_SinglePos( HB_GPOS_SubTable* st,
				 HB_Stream       stream )
{
  HB_Error  error;
  HB_SinglePos*   sp = &st->single;

  HB_UShort         n, m, count, format;
  HB_UInt          cur_offset, new_offset, base_offset;

  HB_ValueRecord*  vr;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 6L ) )
    return error;

  sp->PosFormat = GET_UShort();
  new_offset    = GET_UShort() + base_offset;

  format = sp->ValueFormat = GET_UShort();

  FORGET_Frame();

  if ( !format )
    return ERR(HB_Err_Invalid_SubTable);

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

  switch ( sp->PosFormat )
  {
  case 1:
    error = Load_ValueRecord( &sp->spf.spf1.Value, format,
			      base_offset, stream );
    if ( error )
      goto Fail2;
    break;

  case 2:
    if ( ACCESS_Frame( 2L ) )
      goto Fail2;

    count = sp->spf.spf2.ValueCount = GET_UShort();

    FORGET_Frame();

    sp->spf.spf2.Value = NULL;

    if ( ALLOC_ARRAY( sp->spf.spf2.Value, count, HB_ValueRecord ) )
      goto Fail2;

    vr = sp->spf.spf2.Value;

    for ( n = 0; n < count; n++ )
    {
      error = Load_ValueRecord( &vr[n], format, base_offset, stream );
      if ( error )
	goto Fail1;
    }
    break;

  default:
    return ERR(HB_Err_Invalid_SubTable_Format);
  }

  return HB_Err_Ok;

Fail1:
  for ( m = 0; m < n; m++ )
    Free_ValueRecord( &vr[m], format );

  FREE( vr );

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


static void  Free_SinglePos( HB_GPOS_SubTable* st )
{
  HB_UShort         n, count, format;
  HB_SinglePos*   sp = &st->single;

  HB_ValueRecord*  v;


  format = sp->ValueFormat;

  switch ( sp->PosFormat )
  {
  case 1:
    Free_ValueRecord( &sp->spf.spf1.Value, format );
    break;

  case 2:
    if ( sp->spf.spf2.Value )
    {
      count = sp->spf.spf2.ValueCount;
      v     = sp->spf.spf2.Value;

      for ( n = 0; n < count; n++ )
	Free_ValueRecord( &v[n], format );

      FREE( v );
    }
    break;
  default:
    break;
  }

  _HB_OPEN_Free_Coverage( &sp->Coverage );
}

static HB_Error  Lookup_SinglePos( GPOS_Instance*    gpi,
				   HB_GPOS_SubTable* st,
				   HB_Buffer        buffer,
				   HB_UShort         flags,
				   HB_UShort         context_length,
				   int               nesting_level )
{
  HB_UShort        index, property;
  HB_Error         error;
  HB_GPOSHeader*  gpos = gpi->gpos;
  HB_SinglePos*   sp = &st->single;

  HB_UNUSED(nesting_level);

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

  if ( CHECK_Property( gpos->layout, IN_CURITEM(), flags, &property ) )
    return error;

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

  switch ( sp->PosFormat )
  {
  case 1:
    error = Get_ValueRecord( gpi, &sp->spf.spf1.Value,
			     sp->ValueFormat, POSITION( buffer->in_pos ) );
    if ( error )
      return error;
    break;

  case 2:
    if ( index >= sp->spf.spf2.ValueCount )
      return ERR(HB_Err_Invalid_SubTable);
    error = Get_ValueRecord( gpi, &sp->spf.spf2.Value[index],
			     sp->ValueFormat, POSITION( buffer->in_pos ) );
    if ( error )
      return error;
    break;

  default:
    return ERR(HB_Err_Invalid_SubTable);
  }

  (buffer->in_pos)++;

  return HB_Err_Ok;
}


/* LookupType 2 */

/* PairSet */

static HB_Error  Load_PairSet ( HB_PairSet*  ps,
				HB_UShort     format1,
				HB_UShort     format2,
				HB_Stream     stream )
{
  HB_Error  error;

  HB_UShort             n, m, count;
  HB_UInt              base_offset;

  HB_PairValueRecord*  pvr;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = ps->PairValueCount = GET_UShort();

  FORGET_Frame();

  ps->PairValueRecord = NULL;

  if ( ALLOC_ARRAY( ps->PairValueRecord, count, HB_PairValueRecord ) )
    return error;

  pvr = ps->PairValueRecord;

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

    pvr[n].SecondGlyph = GET_UShort();

    FORGET_Frame();

    if ( format1 )
    {
      error = Load_ValueRecord( &pvr[n].Value1, format1,
				base_offset, stream );
      if ( error )
	goto Fail;
    }
    if ( format2 )
    {
      error = Load_ValueRecord( &pvr[n].Value2, format2,
				base_offset, stream );
      if ( error )
      {
	if ( format1 )
	  Free_ValueRecord( &pvr[n].Value1, format1 );
	goto Fail;
      }
    }
  }

  return HB_Err_Ok;

Fail:
  for ( m = 0; m < n; m++ )
  {
    if ( format1 )
      Free_ValueRecord( &pvr[m].Value1, format1 );
    if ( format2 )
      Free_ValueRecord( &pvr[m].Value2, format2 );
  }

  FREE( pvr );
  return error;
}


static void  Free_PairSet( HB_PairSet*  ps,
			   HB_UShort     format1,
			   HB_UShort     format2 )
{
  HB_UShort             n, count;

  HB_PairValueRecord*  pvr;


  if ( ps->PairValueRecord )
  {
    count = ps->PairValueCount;
    pvr   = ps->PairValueRecord;

    for ( n = 0; n < count; n++ )
    {
      if ( format1 )
	Free_ValueRecord( &pvr[n].Value1, format1 );
      if ( format2 )
	Free_ValueRecord( &pvr[n].Value2, format2 );
    }

    FREE( pvr );
  }
}


/* PairPosFormat1 */

static HB_Error  Load_PairPos1( HB_PairPosFormat1*  ppf1,
				HB_UShort            format1,
				HB_UShort            format2,
				HB_Stream            stream )
{
  HB_Error  error;

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

  HB_PairSet*  ps;


  base_offset = FILE_Pos() - 8L;

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = ppf1->PairSetCount = GET_UShort();

  FORGET_Frame();

  ppf1->PairSet = NULL;

  if ( ALLOC_ARRAY( ppf1->PairSet, count, HB_PairSet ) )
    return error;

  ps = ppf1->PairSet;

  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_PairSet( &ps[n], format1,
				 format2, stream ) ) != HB_Err_Ok )
      goto Fail;
    (void)FILE_Seek( cur_offset );
  }

  return HB_Err_Ok;

Fail:
  for ( m = 0; m < n; m++ )
    Free_PairSet( &ps[m], format1, format2 );

  FREE( ps );
  return error;
}


static void  Free_PairPos1( HB_PairPosFormat1*  ppf1,
			    HB_UShort            format1,
			    HB_UShort            format2 )
{
  HB_UShort     n, count;

  HB_PairSet*  ps;


  if ( ppf1->PairSet )
  {
    count = ppf1->PairSetCount;
    ps    = ppf1->PairSet;

    for ( n = 0; n < count; n++ )
      Free_PairSet( &ps[n], format1, format2 );

    FREE( ps );
  }
}


/* PairPosFormat2 */

static HB_Error  Load_PairPos2( HB_PairPosFormat2*  ppf2,
				HB_UShort            format1,
				HB_UShort            format2,
				HB_Stream            stream )
{
  HB_Error  error;

  HB_UShort          m, n, k, count1, count2;
  HB_UInt           cur_offset, new_offset1, new_offset2, base_offset;

  HB_Class1Record*  c1r;
  HB_Class2Record*  c2r;


  base_offset = FILE_Pos() - 8L;

  if ( ACCESS_Frame( 8L ) )
    return error;

  new_offset1 = GET_UShort() + base_offset;
  new_offset2 = GET_UShort() + base_offset;

  /* `Class1Count' and `Class2Count' are the upper limits for class
     values, thus we read it now to make additional safety checks.  */

  count1 = ppf2->Class1Count = GET_UShort();
  count2 = ppf2->Class2Count = GET_UShort();

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset1 ) ||
       ( error = _HB_OPEN_Load_ClassDefinition( &ppf2->ClassDef1, count1,
				       stream ) ) != HB_Err_Ok )
    return error;
  if ( FILE_Seek( new_offset2 ) ||
       ( error = _HB_OPEN_Load_ClassDefinition( &ppf2->ClassDef2, count2,
				       stream ) ) != HB_Err_Ok )
    goto Fail3;
  (void)FILE_Seek( cur_offset );

  ppf2->Class1Record = NULL;

  if ( ALLOC_ARRAY( ppf2->Class1Record, count1, HB_Class1Record ) )
    goto Fail2;

  c1r = ppf2->Class1Record;

  for ( m = 0; m < count1; m++ )
  {
    c1r[m].Class2Record = NULL;

    if ( ALLOC_ARRAY( c1r[m].Class2Record, count2, HB_Class2Record ) )
      goto Fail1;

    c2r = c1r[m].Class2Record;

    for ( n = 0; n < count2; n++ )
    {
      if ( format1 )
      {
	error = Load_ValueRecord( &c2r[n].Value1, format1,
				  base_offset, stream );
	if ( error )
	  goto Fail0;
      }
      if ( format2 )
      {
	error = Load_ValueRecord( &c2r[n].Value2, format2,
				  base_offset, stream );
	if ( error )
	{
	  if ( format1 )
	    Free_ValueRecord( &c2r[n].Value1, format1 );
	  goto Fail0;
	}
      }
    }

    continue;

  Fail0:
    for ( k = 0; k < n; k++ )
    {
      if ( format1 )
	Free_ValueRecord( &c2r[k].Value1, format1 );
      if ( format2 )
	Free_ValueRecord( &c2r[k].Value2, format2 );
    }
    goto Fail1;
  }

  return HB_Err_Ok;

Fail1:
  for ( k = 0; k < m; k++ )
  {
    c2r = c1r[k].Class2Record;

    for ( n = 0; n < count2; n++ )
    {
      if ( format1 )
	Free_ValueRecord( &c2r[n].Value1, format1 );
      if ( format2 )
	Free_ValueRecord( &c2r[n].Value2, format2 );
    }

    FREE( c2r );
  }

  FREE( c1r );
Fail2:

  _HB_OPEN_Free_ClassDefinition( &ppf2->ClassDef2 );

Fail3:
  _HB_OPEN_Free_ClassDefinition( &ppf2->ClassDef1 );
  return error;
}


static void  Free_PairPos2( HB_PairPosFormat2*  ppf2,
			    HB_UShort            format1,
			    HB_UShort            format2 )
{
  HB_UShort          m, n, count1, count2;

  HB_Class1Record*  c1r;
  HB_Class2Record*  c2r;


  if ( ppf2->Class1Record )
  {
    c1r    = ppf2->Class1Record;
    count1 = ppf2->Class1Count;
    count2 = ppf2->Class2Count;

    for ( m = 0; m < count1; m++ )
    {
      c2r = c1r[m].Class2Record;

      for ( n = 0; n < count2; n++ )
      {
	if ( format1 )
	  Free_ValueRecord( &c2r[n].Value1, format1 );
	if ( format2 )
	  Free_ValueRecord( &c2r[n].Value2, format2 );
      }

      FREE( c2r );
    }

    FREE( c1r );

    _HB_OPEN_Free_ClassDefinition( &ppf2->ClassDef2 );
    _HB_OPEN_Free_ClassDefinition( &ppf2->ClassDef1 );
  }
}


static HB_Error  Load_PairPos( HB_GPOS_SubTable* st,
			       HB_Stream     stream )
{
  HB_Error  error;
  HB_PairPos*     pp = &st->pair;

  HB_UShort         format1, format2;
  HB_UInt          cur_offset, new_offset, base_offset;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 8L ) )
    return error;

  pp->PosFormat = GET_UShort();
  new_offset    = GET_UShort() + base_offset;

  format1 = pp->ValueFormat1 = GET_UShort();
  format2 = pp->ValueFormat2 = GET_UShort();

  FORGET_Frame();

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

  switch ( pp->PosFormat )
  {
  case 1:
    error = Load_PairPos1( &pp->ppf.ppf1, format1, format2, stream );
    if ( error )
      goto Fail;
    break;

  case 2:
    error = Load_PairPos2( &pp->ppf.ppf2, format1, format2, stream );
    if ( error )
      goto Fail;
    break;

  default:
    return ERR(HB_Err_Invalid_SubTable_Format);
  }

  return HB_Err_Ok;

Fail:
  _HB_OPEN_Free_Coverage( &pp->Coverage );
  return error;
}


static void  Free_PairPos( HB_GPOS_SubTable* st )
{
  HB_UShort  format1, format2;
  HB_PairPos*     pp = &st->pair;


  format1 = pp->ValueFormat1;
  format2 = pp->ValueFormat2;

  switch ( pp->PosFormat )
  {
  case 1:
    Free_PairPos1( &pp->ppf.ppf1, format1, format2 );
    break;

  case 2:
    Free_PairPos2( &pp->ppf.ppf2, format1, format2 );
    break;

  default:
    break;
  }

  _HB_OPEN_Free_Coverage( &pp->Coverage );
}


static HB_Error  Lookup_PairPos1( GPOS_Instance*       gpi,
				  HB_PairPosFormat1*  ppf1,
				  HB_Buffer           buffer,
				  HB_UInt             first_pos,
				  HB_UShort            index,
				  HB_UShort            format1,
				  HB_UShort            format2 )
{
  HB_Error              error;
  HB_UShort             numpvr, glyph2;

  HB_PairValueRecord*  pvr;


  if ( index >= ppf1->PairSetCount )
     return ERR(HB_Err_Invalid_SubTable);

  pvr = ppf1->PairSet[index].PairValueRecord;
  if ( !pvr )
    return ERR(HB_Err_Invalid_SubTable);

  glyph2 = IN_CURGLYPH();

  for ( numpvr = ppf1->PairSet[index].PairValueCount;
	numpvr;
	numpvr--, pvr++ )
  {
    if ( glyph2 == pvr->SecondGlyph )
    {
      error = Get_ValueRecord( gpi, &pvr->Value1, format1,
			       POSITION( first_pos ) );
      if ( error )
	return error;
      return Get_ValueRecord( gpi, &pvr->Value2, format2,
			      POSITION( buffer->in_pos ) );
    }
  }

  return HB_Err_Not_Covered;
}


static HB_Error  Lookup_PairPos2( GPOS_Instance*       gpi,
				  HB_PairPosFormat2*  ppf2,
				  HB_Buffer           buffer,
				  HB_UInt             first_pos,
				  HB_UShort            format1,
				  HB_UShort            format2 )
{
  HB_Error           error;
  HB_UShort          cl1 = 0, cl2 = 0; /* shut compiler up */

  HB_Class1Record*  c1r;
  HB_Class2Record*  c2r;


  error = _HB_OPEN_Get_Class( &ppf2->ClassDef1, IN_GLYPH( first_pos ),
		     &cl1, NULL );
  if ( error && error != HB_Err_Not_Covered )
    return error;
  error = _HB_OPEN_Get_Class( &ppf2->ClassDef2, IN_CURGLYPH(),
		     &cl2, NULL );
  if ( error && error != HB_Err_Not_Covered )
    return error;

  c1r = &ppf2->Class1Record[cl1];
  if ( !c1r )
    return ERR(HB_Err_Invalid_SubTable);
  c2r = &c1r->Class2Record[cl2];

  error = Get_ValueRecord( gpi, &c2r->Value1, format1, POSITION( first_pos ) );
  if ( error )
    return error;
  return Get_ValueRecord( gpi, &c2r->Value2, format2, POSITION( buffer->in_pos ) );
}


static HB_Error  Lookup_PairPos( GPOS_Instance*    gpi,
				 HB_GPOS_SubTable* st,
				 HB_Buffer        buffer,
				 HB_UShort         flags,
				 HB_UShort         context_length,
				 int               nesting_level )
{
  HB_Error         error;
  HB_UShort        index, property;
  HB_UInt         first_pos;
  HB_GPOSHeader*  gpos = gpi->gpos;
  HB_PairPos*     pp = &st->pair;

  HB_UNUSED(nesting_level);

  if ( buffer->in_pos >= buffer->in_length - 1 )
    return HB_Err_Not_Covered;           /* Not enough glyphs in stream */

  if ( context_length != 0xFFFF && context_length < 2 )
    return HB_Err_Not_Covered;

  if ( CHECK_Property( gpos->layout, IN_CURITEM(), flags, &property ) )
    return error;

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

  /* second glyph */

  first_pos = buffer->in_pos;
  (buffer->in_pos)++;

  while ( CHECK_Property( gpos->layout, IN_CURITEM(),
			  flags, &property ) )
  {
    if ( error && error != HB_Err_Not_Covered )
      return error;

    if ( buffer->in_pos == buffer->in_length )
      {
	buffer->in_pos = first_pos;
        return HB_Err_Not_Covered;
      }
    (buffer->in_pos)++;

  }

  switch ( pp->PosFormat )
  {
  case 1:
    error = Lookup_PairPos1( gpi, &pp->ppf.ppf1, buffer,
			     first_pos, index,
			     pp->ValueFormat1, pp->ValueFormat2 );
    break;

  case 2:
    error = Lookup_PairPos2( gpi, &pp->ppf.ppf2, buffer, first_pos,
			     pp->ValueFormat1, pp->ValueFormat2 );
    break;

  default:
    return ERR(HB_Err_Invalid_SubTable_Format);
  }

  /* if we don't have coverage for the second glyph don't skip it for
     further lookups but reset in_pos back to the first_glyph and let
     the caller in Do_String_Lookup increment in_pos */
  if ( error == HB_Err_Not_Covered )
      buffer->in_pos = first_pos;

  /* adjusting the `next' glyph */

  if ( pp->ValueFormat2 )
    (buffer->in_pos)++;

  return error;
}


/* LookupType 3 */

/* CursivePosFormat1 */

static HB_Error  Load_CursivePos( HB_GPOS_SubTable* st,
				  HB_Stream        stream )
{
  HB_Error  error;
  HB_CursivePos*  cp = &st->cursive;

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

  HB_EntryExitRecord*  eer;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 4L ) )
    return error;

  cp->PosFormat = GET_UShort();
  new_offset    = GET_UShort() + base_offset;

  FORGET_Frame();

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

  if ( ACCESS_Frame( 2L ) )
    goto Fail2;

  count = cp->EntryExitCount = GET_UShort();

  FORGET_Frame();

  cp->EntryExitRecord = NULL;

  if ( ALLOC_ARRAY( cp->EntryExitRecord, count, HB_EntryExitRecord ) )
    goto Fail2;

  eer = cp->EntryExitRecord;

  for ( n = 0; n < count; n++ )
  {
    HB_UInt entry_offset;

    if ( ACCESS_Frame( 2L ) )
      return error;

    entry_offset = new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = Load_Anchor( &eer[n].EntryAnchor,
				  stream ) ) != HB_Err_Ok )
	goto Fail1;
      (void)FILE_Seek( cur_offset );
    }
    else
      eer[n].EntryAnchor.PosFormat   = 0;

    if ( ACCESS_Frame( 2L ) )
      return error;

    new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = Load_Anchor( &eer[n].ExitAnchor,
				  stream ) ) != HB_Err_Ok )
      {
	if ( entry_offset )
	  Free_Anchor( &eer[n].EntryAnchor );
	goto Fail1;
      }
      (void)FILE_Seek( cur_offset );
    }
    else
      eer[n].ExitAnchor.PosFormat   = 0;
  }

  return HB_Err_Ok;

Fail1:
  for ( m = 0; m < n; m++ )
  {
    Free_Anchor( &eer[m].EntryAnchor );
    Free_Anchor( &eer[m].ExitAnchor );
  }

  FREE( eer );

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


static void  Free_CursivePos( HB_GPOS_SubTable* st )
{
  HB_UShort             n, count;
  HB_CursivePos*  cp = &st->cursive;

  HB_EntryExitRecord*  eer;


  if ( cp->EntryExitRecord )
  {
    count = cp->EntryExitCount;
    eer   = cp->EntryExitRecord;

    for ( n = 0; n < count; n++ )
    {
      Free_Anchor( &eer[n].EntryAnchor );
      Free_Anchor( &eer[n].ExitAnchor );
    }

    FREE( eer );
  }

  _HB_OPEN_Free_Coverage( &cp->Coverage );
}


static HB_Error  Lookup_CursivePos( GPOS_Instance*    gpi,
				    HB_GPOS_SubTable* st,
				    HB_Buffer        buffer,
				    HB_UShort         flags,
				    HB_UShort         context_length,
				    int               nesting_level )
{
  HB_UShort        index, property;
  HB_Error         error;
  HB_GPOSHeader*  gpos = gpi->gpos;
  HB_CursivePos*  cp = &st->cursive;

  HB_EntryExitRecord*  eer;
  HB_Fixed                entry_x, entry_y;
  HB_Fixed                exit_x, exit_y;

  HB_UNUSED(nesting_level);

  if ( context_length != 0xFFFF && context_length < 1 )
  {
    gpi->last = 0xFFFF;
    return HB_Err_Not_Covered;
  }

  /* Glyphs not having the right GDEF property will be ignored, i.e.,
     gpi->last won't be reset (contrary to user defined properties). */

  if ( CHECK_Property( gpos->layout, IN_CURITEM(), flags, &property ) )
    return error;

  /* We don't handle mark glyphs here.  According to Andrei, this isn't
     possible, but who knows...                                         */

  if ( property == HB_OT_LAYOUT_GLYPH_CLASS_MARK )
  {
    gpi->last = 0xFFFF;
    return HB_Err_Not_Covered;
  }

  error = _HB_OPEN_Coverage_Index( &cp->Coverage, IN_CURGLYPH(), &index );
  if ( error )
  {
    gpi->last = 0xFFFF;
    return error;
  }

  if ( index >= cp->EntryExitCount )
    return ERR(HB_Err_Invalid_SubTable);

  eer = &cp->EntryExitRecord[index];

  /* Now comes the messiest part of the whole OpenType
     specification.  At first glance, cursive connections seem easy
     to understand, but there are pitfalls!  The reason is that
     the specs don't mention how to compute the advance values
     resp. glyph offsets.  I was told it would be an omission, to
     be fixed in the next OpenType version...  Again many thanks to
     Andrei Burago <andreib@microsoft.com> for clarifications.

     Consider the following example:

		      |  xadv1    |
		       +---------+
		       |         |
		 +-----+--+ 1    |
		 |     | .|      |
		 |    0+--+------+
		 |   2    |
		 |        |
		0+--------+
		|  xadv2   |

       glyph1: advance width = 12
	       anchor point = (3,1)

       glyph2: advance width = 11
	       anchor point = (9,4)

       LSB is 1 for both glyphs (so the boxes drawn above are glyph
       bboxes).  Writing direction is R2L; `0' denotes the glyph's
       coordinate origin.

     Now the surprising part: The advance width of the *left* glyph
     (resp. of the *bottom* glyph) will be modified, no matter
     whether the writing direction is L2R or R2L (resp. T2B or
     B2T)!  This assymetry is caused by the fact that the glyph's
     coordinate origin is always the lower left corner for all
     writing directions.

     Continuing the above example, we can compute the new
     (horizontal) advance width of glyph2 as

       9 - 3 = 6  ,

     and the new vertical offset of glyph2 as

       1 - 4 = -3  .


     Vertical writing direction is far more complicated:

     a) Assuming that we recompute the advance height of the lower glyph:

				  --
		       +---------+
	      --       |         |
		 +-----+--+ 1    | yadv1
		 |     | .|      |
	   yadv2 |    0+--+------+        -- BSB1  --
		 |   2    |       --      --        y_offset
		 |        |
   BSB2 --      0+--------+                        --
	--    --

       glyph1: advance height = 6
	       anchor point = (3,1)

       glyph2: advance height = 7
	       anchor point = (9,4)

       TSB is 1 for both glyphs; writing direction is T2B.


	 BSB1     = yadv1 - (TSB1 + ymax1)
	 BSB2     = yadv2 - (TSB2 + ymax2)
	 y_offset = y2 - y1

       vertical advance width of glyph2
	 = y_offset + BSB2 - BSB1
	 = (y2 - y1) + (yadv2 - (TSB2 + ymax2)) - (yadv1 - (TSB1 + ymax1))
	 = y2 - y1 + yadv2 - TSB2 - ymax2 - (yadv1 - TSB1 - ymax1)
	 = y2 - y1 + yadv2 - TSB2 - ymax2 - yadv1 + TSB1 + ymax1


     b) Assuming that we recompute the advance height of the upper glyph:

				  --      --
		       +---------+        -- TSB1
	--    --       |         |
   TSB2 --       +-----+--+ 1    | yadv1   ymax1
		 |     | .|      |
	   yadv2 |    0+--+------+        --       --
    ymax2        |   2    |       --                y_offset
		 |        |
	--      0+--------+                        --
	      --

       glyph1: advance height = 6
	       anchor point = (3,1)

       glyph2: advance height = 7
	       anchor point = (9,4)

       TSB is 1 for both glyphs; writing direction is T2B.

       y_offset = y2 - y1

       vertical advance width of glyph2
	 = TSB1 + ymax1 + y_offset - (TSB2 + ymax2)
	 = TSB1 + ymax1 + y2 - y1 - TSB2 - ymax2


     Comparing a) with b) shows that b) is easier to compute.  I'll wait
     for a reply from Andrei to see what should really be implemented...

     Since horizontal advance widths or vertical advance heights
     can be used alone but not together, no ambiguity occurs.        */

  if ( gpi->last == 0xFFFF )
    goto end;

  /* Get_Anchor() returns HB_Err_Not_Covered if there is no anchor
     table.                                                         */

  error = Get_Anchor( gpi, &eer->EntryAnchor, IN_CURGLYPH(),
		      &entry_x, &entry_y );
  if ( error == HB_Err_Not_Covered )
    goto end;
  if ( error )
    return error;

  if ( gpi->r2l )
  {
    POSITION( buffer->in_pos )->x_advance   = entry_x - gpi->anchor_x;
    POSITION( buffer->in_pos )->new_advance = TRUE;
  }
  else
  {
    POSITION( gpi->last )->x_advance   = gpi->anchor_x - entry_x;
    POSITION( gpi->last )->new_advance = TRUE;
  }

  if ( flags & HB_LOOKUP_FLAG_RIGHT_TO_LEFT )
  {
    POSITION( gpi->last )->cursive_chain = gpi->last - buffer->in_pos;
    POSITION( gpi->last )->y_pos = entry_y - gpi->anchor_y;
  }
  else
  {
    POSITION( buffer->in_pos )->cursive_chain = buffer->in_pos - gpi->last;
    POSITION( buffer->in_pos )->y_pos = gpi->anchor_y - entry_y;
  }

end:
  error = Get_Anchor( gpi, &eer->ExitAnchor, IN_CURGLYPH(),
		      &exit_x, &exit_y );
  if ( error == HB_Err_Not_Covered )
    gpi->last = 0xFFFF;
  else
  {
    gpi->last     = buffer->in_pos;
    gpi->anchor_x = exit_x;
    gpi->anchor_y = exit_y;
  }
  if ( error )
    return error;

  (buffer->in_pos)++;

  return HB_Err_Ok;
}


/* LookupType 4 */

/* BaseArray */

static HB_Error  Load_BaseArray( HB_BaseArray*  ba,
				 HB_UShort       num_classes,
				 HB_Stream       stream )
{
  HB_Error  error;

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

  HB_BaseRecord  *br;
  HB_Anchor      *ban, *bans;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = ba->BaseCount = GET_UShort();

  FORGET_Frame();

  ba->BaseRecord = NULL;

  if ( ALLOC_ARRAY( ba->BaseRecord, count, HB_BaseRecord ) )
    return error;

  br = ba->BaseRecord;

  bans = NULL;

  if ( ALLOC_ARRAY( bans, count * num_classes, HB_Anchor ) )
    goto Fail;

  for ( m = 0; m < count; m++ )
  {
    br[m].BaseAnchor = NULL;

    ban = br[m].BaseAnchor = bans + m * num_classes;

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

      new_offset = GET_UShort() + base_offset;

      FORGET_Frame();

      if (new_offset == base_offset) {
	/* XXX
	 * Doulos SIL Regular is buggy and has zero offsets here.
	 * Skip it
	 */
	ban[n].PosFormat = 0;
	continue;
      }

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = Load_Anchor( &ban[n], stream ) ) != HB_Err_Ok )
	goto Fail;
      (void)FILE_Seek( cur_offset );
    }
  }

  return HB_Err_Ok;

Fail:
  FREE( bans );
  FREE( br );
  return error;
}


static void  Free_BaseArray( HB_BaseArray*  ba,
			     HB_UShort       num_classes )
{
  HB_BaseRecord  *br;
  HB_Anchor      *bans;

  HB_UNUSED(num_classes);

  if ( ba->BaseRecord )
  {
    br    = ba->BaseRecord;

    if ( ba->BaseCount )
    {
      bans = br[0].BaseAnchor;
      FREE( bans );
    }

    FREE( br );
  }
}


/* MarkBasePosFormat1 */

static HB_Error  Load_MarkBasePos( HB_GPOS_SubTable* st,
				   HB_Stream         stream )
{
  HB_Error  error;
  HB_MarkBasePos* mbp = &st->markbase;

  HB_UInt  cur_offset, new_offset, base_offset;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 4L ) )
    return error;

  mbp->PosFormat = GET_UShort();
  new_offset     = GET_UShort() + base_offset;

  FORGET_Frame();

  if (mbp->PosFormat != 1)
    return ERR(HB_Err_Invalid_SubTable_Format);

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

  if ( ACCESS_Frame( 2L ) )
    goto Fail3;

  new_offset = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_Coverage( &mbp->BaseCoverage, stream ) ) != HB_Err_Ok )
    goto Fail3;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 4L ) )
    goto Fail2;

  mbp->ClassCount = GET_UShort();
  new_offset      = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = Load_MarkArray( &mbp->MarkArray, stream ) ) != HB_Err_Ok )
    goto Fail2;
  (void)FILE_Seek( cur_offset );

  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_BaseArray( &mbp->BaseArray, mbp->ClassCount,
				 stream ) ) != HB_Err_Ok )
    goto Fail1;

  return HB_Err_Ok;

Fail1:
  Free_MarkArray( &mbp->MarkArray );

Fail2:
  _HB_OPEN_Free_Coverage( &mbp->BaseCoverage );

Fail3:
  _HB_OPEN_Free_Coverage( &mbp->MarkCoverage );
  return error;
}


static void  Free_MarkBasePos( HB_GPOS_SubTable* st )
{
  HB_MarkBasePos* mbp = &st->markbase;

  Free_BaseArray( &mbp->BaseArray, mbp->ClassCount );
  Free_MarkArray( &mbp->MarkArray );
  _HB_OPEN_Free_Coverage( &mbp->BaseCoverage );
  _HB_OPEN_Free_Coverage( &mbp->MarkCoverage );
}


static HB_Error  Lookup_MarkBasePos( GPOS_Instance*    gpi,
				     HB_GPOS_SubTable* st,
				     HB_Buffer        buffer,
				     HB_UShort         flags,
				     HB_UShort         context_length,
				     int               nesting_level )
{
  HB_UShort        i, j, mark_index, base_index, property, class;
  HB_Fixed           x_mark_value, y_mark_value, x_base_value, y_base_value;
  HB_Error         error;
  HB_GPOSHeader*  gpos = gpi->gpos;
  HB_MarkBasePos* mbp = &st->markbase;

  HB_MarkArray*   ma;
  HB_BaseArray*   ba;
  HB_BaseRecord*  br;
  HB_Anchor*      mark_anchor;
  HB_Anchor*      base_anchor;

  HB_Position     o;

  HB_UNUSED(nesting_level);

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

  if ( flags & HB_LOOKUP_FLAG_IGNORE_BASE_GLYPHS )
    return HB_Err_Not_Covered;

  if ( CHECK_Property( gpos->layout, IN_CURITEM(),
		       flags, &property ) )
    return error;

  error = _HB_OPEN_Coverage_Index( &mbp->MarkCoverage, IN_CURGLYPH(),
			  &mark_index );
  if ( error )
    return error;

  /* now we search backwards for a non-mark glyph */

  i = 1;
  j = buffer->in_pos - 1;

  while ( i <= buffer->in_pos )
  {
    property = _hb_ot_layout_get_glyph_property (gpos->layout, IN_GLYPH(j));
    if ( !property )
      return HB_Err_Not_Covered;

    if ( !( property == HB_OT_LAYOUT_GLYPH_CLASS_MARK || property & HB_LOOKUP_FLAG_IGNORE_SPECIAL_MARKS ) )
      break;

    i++;
    j--;
  }

  /* The following assertion is too strong -- at least for mangal.ttf. */
#if 0
  if ( property != HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH )
    return HB_Err_Not_Covered;
#endif

  if ( i > buffer->in_pos )
    return HB_Err_Not_Covered;

  error = _HB_OPEN_Coverage_Index( &mbp->BaseCoverage, IN_GLYPH( j ),
			  &base_index );
  if ( error )
    return error;

  ma = &mbp->MarkArray;

  if ( mark_index >= ma->MarkCount )
    return ERR(HB_Err_Invalid_SubTable);

  class       = ma->MarkRecord[mark_index].Class;
  mark_anchor = &ma->MarkRecord[mark_index].MarkAnchor;

  if ( class >= mbp->ClassCount )
    return ERR(HB_Err_Invalid_SubTable);

  ba = &mbp->BaseArray;

  if ( base_index >= ba->BaseCount )
    return ERR(HB_Err_Invalid_SubTable);

  br          = &ba->BaseRecord[base_index];
  base_anchor = &br->BaseAnchor[class];

  error = Get_Anchor( gpi, mark_anchor, IN_CURGLYPH(),
		      &x_mark_value, &y_mark_value );
  if ( error )
    return error;

  error = Get_Anchor( gpi, base_anchor, IN_GLYPH( j ),
		      &x_base_value, &y_base_value );
  if ( error )
    return error;

  /* anchor points are not cumulative */

  o = POSITION( buffer->in_pos );

  o->x_pos     = x_base_value - x_mark_value;
  o->y_pos     = y_base_value - y_mark_value;
  o->x_advance = 0;
  o->y_advance = 0;
  o->back      = i;

  (buffer->in_pos)++;

  return HB_Err_Ok;
}


/* LookupType 5 */

/* LigatureAttach */

static HB_Error  Load_LigatureAttach( HB_LigatureAttach*  lat,
				      HB_UShort            num_classes,
				      HB_Stream            stream )
{
  HB_Error  error;

  HB_UShort             m, n, k, count;
  HB_UInt              cur_offset, new_offset, base_offset;

  HB_ComponentRecord*  cr;
  HB_Anchor*           lan;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = lat->ComponentCount = GET_UShort();

  FORGET_Frame();

  lat->ComponentRecord = NULL;

  if ( ALLOC_ARRAY( lat->ComponentRecord, count, HB_ComponentRecord ) )
    return error;

  cr = lat->ComponentRecord;

  for ( m = 0; m < count; m++ )
  {
    cr[m].LigatureAnchor = NULL;

    if ( ALLOC_ARRAY( cr[m].LigatureAnchor, num_classes, HB_Anchor ) )
      goto Fail;

    lan = cr[m].LigatureAnchor;

    for ( n = 0; n < num_classes; n++ )
    {
      if ( ACCESS_Frame( 2L ) )
	goto Fail0;

      new_offset = GET_UShort();

      FORGET_Frame();

      if ( new_offset )
      {
	new_offset += base_offset;

	cur_offset = FILE_Pos();
	if ( FILE_Seek( new_offset ) ||
	     ( error = Load_Anchor( &lan[n], stream ) ) != HB_Err_Ok )
	  goto Fail0;
	(void)FILE_Seek( cur_offset );
      }
      else
	lan[n].PosFormat = 0;
    }

    continue;
  Fail0:
    for ( k = 0; k < n; k++ )
      Free_Anchor( &lan[k] );
    goto Fail;
  }

  return HB_Err_Ok;

Fail:
  for ( k = 0; k < m; k++ )
  {
    lan = cr[k].LigatureAnchor;

    for ( n = 0; n < num_classes; n++ )
      Free_Anchor( &lan[n] );

    FREE( lan );
  }

  FREE( cr );
  return error;
}


static void  Free_LigatureAttach( HB_LigatureAttach*  lat,
				  HB_UShort            num_classes )
{
  HB_UShort        m, n, count;

  HB_ComponentRecord*  cr;
  HB_Anchor*           lan;


  if ( lat->ComponentRecord )
  {
    count = lat->ComponentCount;
    cr    = lat->ComponentRecord;

    for ( m = 0; m < count; m++ )
    {
      lan = cr[m].LigatureAnchor;

      for ( n = 0; n < num_classes; n++ )
	Free_Anchor( &lan[n] );

      FREE( lan );
    }

    FREE( cr );
  }
}


/* LigatureArray */

static HB_Error  Load_LigatureArray( HB_LigatureArray*  la,
				     HB_UShort           num_classes,
				     HB_Stream           stream )
{
  HB_Error  error;

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

  HB_LigatureAttach*  lat;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = la->LigatureCount = GET_UShort();

  FORGET_Frame();

  la->LigatureAttach = NULL;

  if ( ALLOC_ARRAY( la->LigatureAttach, count, HB_LigatureAttach ) )
    return error;

  lat = la->LigatureAttach;

  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_LigatureAttach( &lat[n], num_classes,
					stream ) ) != HB_Err_Ok )
      goto Fail;
    (void)FILE_Seek( cur_offset );
  }

  return HB_Err_Ok;

Fail:
  for ( m = 0; m < n; m++ )
    Free_LigatureAttach( &lat[m], num_classes );

  FREE( lat );
  return error;
}


static void  Free_LigatureArray( HB_LigatureArray*  la,
				 HB_UShort          num_classes )
{
  HB_UShort            n, count;

  HB_LigatureAttach*  lat;


  if ( la->LigatureAttach )
  {
    count = la->LigatureCount;
    lat   = la->LigatureAttach;

    for ( n = 0; n < count; n++ )
      Free_LigatureAttach( &lat[n], num_classes );

    FREE( lat );
  }
}


/* MarkLigPosFormat1 */

static HB_Error  Load_MarkLigPos( HB_GPOS_SubTable* st,
				  HB_Stream        stream )
{
  HB_Error  error;
  HB_MarkLigPos*  mlp = &st->marklig;

  HB_UInt  cur_offset, new_offset, base_offset;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 4L ) )
    return error;

  mlp->PosFormat = GET_UShort();
  new_offset     = GET_UShort() + base_offset;

  FORGET_Frame();

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

  if ( ACCESS_Frame( 2L ) )
    goto Fail3;

  new_offset = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_Coverage( &mlp->LigatureCoverage,
				stream ) ) != HB_Err_Ok )
    goto Fail3;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 4L ) )
    goto Fail2;

  mlp->ClassCount = GET_UShort();
  new_offset      = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = Load_MarkArray( &mlp->MarkArray, stream ) ) != HB_Err_Ok )
    goto Fail2;
  (void)FILE_Seek( cur_offset );

  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_LigatureArray( &mlp->LigatureArray, mlp->ClassCount,
				     stream ) ) != HB_Err_Ok )
    goto Fail1;

  return HB_Err_Ok;

Fail1:
  Free_MarkArray( &mlp->MarkArray );

Fail2:
  _HB_OPEN_Free_Coverage( &mlp->LigatureCoverage );

Fail3:
  _HB_OPEN_Free_Coverage( &mlp->MarkCoverage );
  return error;
}


static void  Free_MarkLigPos( HB_GPOS_SubTable* st )
{
  HB_MarkLigPos*  mlp = &st->marklig;

  Free_LigatureArray( &mlp->LigatureArray, mlp->ClassCount );
  Free_MarkArray( &mlp->MarkArray );
  _HB_OPEN_Free_Coverage( &mlp->LigatureCoverage );
  _HB_OPEN_Free_Coverage( &mlp->MarkCoverage );
}


static HB_Error  Lookup_MarkLigPos( GPOS_Instance*    gpi,
				    HB_GPOS_SubTable* st,
				    HB_Buffer        buffer,
				    HB_UShort         flags,
				    HB_UShort         context_length,
				    int               nesting_level )
{
  HB_UShort        i, j, mark_index, lig_index, property, class;
  HB_UShort        mark_glyph;
  HB_Fixed           x_mark_value, y_mark_value, x_lig_value, y_lig_value;
  HB_Error         error;
  HB_GPOSHeader*  gpos = gpi->gpos;
  HB_MarkLigPos*  mlp = &st->marklig;

  HB_MarkArray*        ma;
  HB_LigatureArray*    la;
  HB_LigatureAttach*   lat;
  HB_ComponentRecord*  cr;
  HB_UShort             comp_index;
  HB_Anchor*           mark_anchor;
  HB_Anchor*           lig_anchor;

  HB_Position    o;

  HB_UNUSED(nesting_level);

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

  if ( flags & HB_LOOKUP_FLAG_IGNORE_LIGATURES )
    return HB_Err_Not_Covered;

  mark_glyph = IN_CURGLYPH();

  if ( CHECK_Property( gpos->layout, IN_CURITEM(), flags, &property ) )
    return error;

  error = _HB_OPEN_Coverage_Index( &mlp->MarkCoverage, mark_glyph, &mark_index );
  if ( error )
    return error;

  /* now we search backwards for a non-mark glyph */

  i = 1;
  j = buffer->in_pos - 1;

  while ( i <= buffer->in_pos )
  {
    property = _hb_ot_layout_get_glyph_property (gpos->layout, IN_GLYPH(j));
    if ( !property )
      return HB_Err_Not_Covered;

    if ( !( property == HB_OT_LAYOUT_GLYPH_CLASS_MARK || property & HB_LOOKUP_FLAG_IGNORE_SPECIAL_MARKS ) )
      break;

    i++;
    j--;
  }

  /* Similar to Lookup_MarkBasePos(), I suspect that this assertion is
     too strong, thus it is commented out.                             */
#if 0
  if ( property != HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE )
    return HB_Err_Not_Covered;
#endif

  if ( i > buffer->in_pos )
    return HB_Err_Not_Covered;

  error = _HB_OPEN_Coverage_Index( &mlp->LigatureCoverage, IN_GLYPH( j ),
			  &lig_index );
  if ( error )
    return error;

  ma = &mlp->MarkArray;

  if ( mark_index >= ma->MarkCount )
    return ERR(HB_Err_Invalid_SubTable);

  class       = ma->MarkRecord[mark_index].Class;
  mark_anchor = &ma->MarkRecord[mark_index].MarkAnchor;

  if ( class >= mlp->ClassCount )
    return ERR(HB_Err_Invalid_SubTable);

  la = &mlp->LigatureArray;

  if ( lig_index >= la->LigatureCount )
    return ERR(HB_Err_Invalid_SubTable);

  lat = &la->LigatureAttach[lig_index];

  /* We must now check whether the ligature ID of the current mark glyph
     is identical to the ligature ID of the found ligature.  If yes, we
     can directly use the component index.  If not, we attach the mark
     glyph to the last component of the ligature.                        */

  if ( IN_LIGID( j ) == IN_LIGID( buffer->in_pos) )
  {
    comp_index = IN_COMPONENT( buffer->in_pos );
    if ( comp_index >= lat->ComponentCount )
      return HB_Err_Not_Covered;
  }
  else
    comp_index = lat->ComponentCount - 1;

  cr         = &lat->ComponentRecord[comp_index];
  lig_anchor = &cr->LigatureAnchor[class];

  error = Get_Anchor( gpi, mark_anchor, IN_CURGLYPH(),
		      &x_mark_value, &y_mark_value );
  if ( error )
    return error;
  error = Get_Anchor( gpi, lig_anchor, IN_GLYPH( j ),
		      &x_lig_value, &y_lig_value );
  if ( error )
    return error;

  /* anchor points are not cumulative */

  o = POSITION( buffer->in_pos );

  o->x_pos     = x_lig_value - x_mark_value;
  o->y_pos     = y_lig_value - y_mark_value;
  o->x_advance = 0;
  o->y_advance = 0;
  o->back      = i;

  (buffer->in_pos)++;

  return HB_Err_Ok;
}


/* LookupType 6 */

/* Mark2Array */

static HB_Error  Load_Mark2Array( HB_Mark2Array*  m2a,
				  HB_UShort        num_classes,
				  HB_Stream        stream )
{
  HB_Error  error;

  HB_UShort        k, m, n, count;
  HB_UInt          cur_offset, new_offset, base_offset;

  HB_Mark2Record  *m2r;
  HB_Anchor       *m2an, *m2ans;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = m2a->Mark2Count = GET_UShort();

  FORGET_Frame();

  m2a->Mark2Record = NULL;

  if ( ALLOC_ARRAY( m2a->Mark2Record, count, HB_Mark2Record ) )
    return error;

  m2r = m2a->Mark2Record;

  m2ans = NULL;

  if ( ALLOC_ARRAY( m2ans, count * num_classes, HB_Anchor ) )
    goto Fail;

  for ( m = 0; m < count; m++ )
  {
    m2an = m2r[m].Mark2Anchor = m2ans + m * num_classes;

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

      new_offset = GET_UShort() + base_offset;

      FORGET_Frame();

      if (new_offset == base_offset) {
        /* Anchor table not provided.  Skip loading.
	 * Some versions of FreeSans hit this. */
        m2an[n].PosFormat = 0;
	continue;
      }

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = Load_Anchor( &m2an[n], stream ) ) != HB_Err_Ok )
	goto Fail;
      (void)FILE_Seek( cur_offset );
    }
  }

  return HB_Err_Ok;

Fail:
  FREE( m2ans );
  FREE( m2r );
  return error;
}


static void  Free_Mark2Array( HB_Mark2Array*  m2a,
			      HB_UShort        num_classes )
{
  HB_Mark2Record  *m2r;
  HB_Anchor       *m2ans;

  HB_UNUSED(num_classes);

  if ( m2a->Mark2Record )
  {
    m2r   = m2a->Mark2Record;

    if ( m2a->Mark2Count )
    {
      m2ans = m2r[0].Mark2Anchor;
      FREE( m2ans );
    }

    FREE( m2r );
  }
}


/* MarkMarkPosFormat1 */

static HB_Error  Load_MarkMarkPos( HB_GPOS_SubTable* st,
				   HB_Stream         stream )
{
  HB_Error  error;
  HB_MarkMarkPos* mmp = &st->markmark;

  HB_UInt  cur_offset, new_offset, base_offset;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 4L ) )
    return error;

  mmp->PosFormat = GET_UShort();
  new_offset     = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_Coverage( &mmp->Mark1Coverage,
				stream ) ) != HB_Err_Ok )
    return error;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 2L ) )
    goto Fail3;

  new_offset = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_Coverage( &mmp->Mark2Coverage,
				stream ) ) != HB_Err_Ok )
    goto Fail3;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 4L ) )
    goto Fail2;

  mmp->ClassCount = GET_UShort();
  new_offset      = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = Load_MarkArray( &mmp->Mark1Array, stream ) ) != HB_Err_Ok )
    goto Fail2;
  (void)FILE_Seek( cur_offset );

  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_Mark2Array( &mmp->Mark2Array, mmp->ClassCount,
				  stream ) ) != HB_Err_Ok )
    goto Fail1;

  return HB_Err_Ok;

Fail1:
  Free_MarkArray( &mmp->Mark1Array );

Fail2:
  _HB_OPEN_Free_Coverage( &mmp->Mark2Coverage );

Fail3:
  _HB_OPEN_Free_Coverage( &mmp->Mark1Coverage );
  return error;
}


static void  Free_MarkMarkPos( HB_GPOS_SubTable* st )
{
  HB_MarkMarkPos* mmp = &st->markmark;

  Free_Mark2Array( &mmp->Mark2Array, mmp->ClassCount );
  Free_MarkArray( &mmp->Mark1Array );
  _HB_OPEN_Free_Coverage( &mmp->Mark2Coverage );
  _HB_OPEN_Free_Coverage( &mmp->Mark1Coverage );
}


static HB_Error  Lookup_MarkMarkPos( GPOS_Instance*    gpi,
				     HB_GPOS_SubTable* st,
				     HB_Buffer        buffer,
				     HB_UShort         flags,
				     HB_UShort         context_length,
				     int               nesting_level )
{
  HB_UShort        i, j, mark1_index, mark2_index, property, class;
  HB_Fixed           x_mark1_value, y_mark1_value,
		   x_mark2_value, y_mark2_value;
  HB_Error         error;
  HB_GPOSHeader*  gpos = gpi->gpos;
  HB_MarkMarkPos* mmp = &st->markmark;

  HB_MarkArray*    ma1;
  HB_Mark2Array*   ma2;
  HB_Mark2Record*  m2r;
  HB_Anchor*       mark1_anchor;
  HB_Anchor*       mark2_anchor;

  HB_Position    o;

  HB_UNUSED(nesting_level);

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

  if ( flags & HB_LOOKUP_FLAG_IGNORE_MARKS )
    return HB_Err_Not_Covered;

  if ( CHECK_Property( gpos->layout, IN_CURITEM(),
		       flags, &property ) )
    return error;

  error = _HB_OPEN_Coverage_Index( &mmp->Mark1Coverage, IN_CURGLYPH(),
			  &mark1_index );
  if ( error )
    return error;

  /* now we search backwards for a suitable mark glyph until a non-mark
     glyph                                                */

  if ( buffer->in_pos == 0 )
    return HB_Err_Not_Covered;

  i = 1;
  j = buffer->in_pos - 1;
  while ( i <= buffer->in_pos )
  {
    property = _hb_ot_layout_get_glyph_property (gpos->layout, IN_GLYPH(j));
    if ( !property )
      return HB_Err_Not_Covered;

    if ( !( property == HB_OT_LAYOUT_GLYPH_CLASS_MARK || property & HB_LOOKUP_FLAG_IGNORE_SPECIAL_MARKS ) )
      return HB_Err_Not_Covered;

    if ( flags & HB_LOOKUP_FLAG_IGNORE_SPECIAL_MARKS )
    {
      if ( property == (flags & 0xFF00) )
        break;
    }
    else
      break;

    i++;
    j--;
  }

  error = _HB_OPEN_Coverage_Index( &mmp->Mark2Coverage, IN_GLYPH( j ),
			  &mark2_index );
  if ( error )
    return error;

  ma1 = &mmp->Mark1Array;

  if ( mark1_index >= ma1->MarkCount )
    return ERR(HB_Err_Invalid_SubTable);

  class        = ma1->MarkRecord[mark1_index].Class;
  mark1_anchor = &ma1->MarkRecord[mark1_index].MarkAnchor;

  if ( class >= mmp->ClassCount )
    return ERR(HB_Err_Invalid_SubTable);

  ma2 = &mmp->Mark2Array;

  if ( mark2_index >= ma2->Mark2Count )
    return ERR(HB_Err_Invalid_SubTable);

  m2r          = &ma2->Mark2Record[mark2_index];
  mark2_anchor = &m2r->Mark2Anchor[class];

  error = Get_Anchor( gpi, mark1_anchor, IN_CURGLYPH(),
		      &x_mark1_value, &y_mark1_value );
  if ( error )
    return error;
  error = Get_Anchor( gpi, mark2_anchor, IN_GLYPH( j ),
		      &x_mark2_value, &y_mark2_value );
  if ( error )
    return error;

  /* anchor points are not cumulative */

  o = POSITION( buffer->in_pos );

  o->x_pos     = x_mark2_value - x_mark1_value;
  o->y_pos     = y_mark2_value - y_mark1_value;
  o->x_advance = 0;
  o->y_advance = 0;
  o->back      = 1;

  (buffer->in_pos)++;

  return HB_Err_Ok;
}


/* Do the actual positioning for a context positioning (either format
   7 or 8).  This is only called after we've determined that the stream
   matches the subrule.                                                 */

static HB_Error  Do_ContextPos( GPOS_Instance*        gpi,
				HB_UShort             GlyphCount,
				HB_UShort             PosCount,
				HB_PosLookupRecord*  pos,
				HB_Buffer            buffer,
				int                   nesting_level )
{
  HB_Error  error;
  HB_UInt i, old_pos;


  i = 0;

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

      /* Do a positioning */

      error = GPOS_Do_Glyph_Lookup( gpi, pos->LookupListIndex, buffer,
				    GlyphCount, nesting_level );

      if ( error )
	return error;

      pos++;
      PosCount--;
      i += buffer->in_pos - old_pos;
    }
    else
    {
      i++;
      (buffer->in_pos)++;
    }
  }

  return HB_Err_Ok;
}


/* LookupType 7 */

/* PosRule */

static HB_Error  Load_PosRule( HB_PosRule*  pr,
			       HB_Stream     stream )
{
  HB_Error  error;

  HB_UShort             n, count;
  HB_UShort*            i;

  HB_PosLookupRecord*  plr;


  if ( ACCESS_Frame( 4L ) )
    return error;

  pr->GlyphCount = GET_UShort();
  pr->PosCount   = GET_UShort();

  FORGET_Frame();

  pr->Input = NULL;

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

  if ( ALLOC_ARRAY( pr->Input, count, HB_UShort ) )
    return error;

  i = pr->Input;

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

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

  FORGET_Frame();

  pr->PosLookupRecord = NULL;

  count = pr->PosCount;

  if ( ALLOC_ARRAY( pr->PosLookupRecord, count, HB_PosLookupRecord ) )
    goto Fail2;

  plr = pr->PosLookupRecord;

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

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

  FORGET_Frame();

  return HB_Err_Ok;

Fail1:
  FREE( plr );

Fail2:
  FREE( i );
  return error;
}


static void  Free_PosRule( HB_PosRule*  pr )
{
  FREE( pr->PosLookupRecord );
  FREE( pr->Input );
}


/* PosRuleSet */

static HB_Error  Load_PosRuleSet( HB_PosRuleSet*  prs,
				  HB_Stream        stream )
{
  HB_Error  error;

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

  HB_PosRule*  pr;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = prs->PosRuleCount = GET_UShort();

  FORGET_Frame();

  prs->PosRule = NULL;

  if ( ALLOC_ARRAY( prs->PosRule, count, HB_PosRule ) )
    return error;

  pr = prs->PosRule;

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

  return HB_Err_Ok;

Fail:
  for ( m = 0; m < n; m++ )
    Free_PosRule( &pr[m] );

  FREE( pr );
  return error;
}


static void  Free_PosRuleSet( HB_PosRuleSet*  prs )
{
  HB_UShort     n, count;

  HB_PosRule*  pr;


  if ( prs->PosRule )
  {
    count = prs->PosRuleCount;
    pr    = prs->PosRule;

    for ( n = 0; n < count; n++ )
      Free_PosRule( &pr[n] );

    FREE( pr );
  }
}


/* ContextPosFormat1 */

static HB_Error  Load_ContextPos1( HB_ContextPosFormat1*  cpf1,
				   HB_Stream               stream )
{
  HB_Error  error;

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

  HB_PosRuleSet*  prs;


  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 = _HB_OPEN_Load_Coverage( &cpf1->Coverage, stream ) ) != HB_Err_Ok )
    return error;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 2L ) )
    goto Fail2;

  count = cpf1->PosRuleSetCount = GET_UShort();

  FORGET_Frame();

  cpf1->PosRuleSet = NULL;

  if ( ALLOC_ARRAY( cpf1->PosRuleSet, count, HB_PosRuleSet ) )
    goto Fail2;

  prs = cpf1->PosRuleSet;

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

  return HB_Err_Ok;

Fail1:
  for ( m = 0; m < n; m++ )
    Free_PosRuleSet( &prs[m] );

  FREE( prs );

Fail2:
  _HB_OPEN_Free_Coverage( &cpf1->Coverage );
  return error;
}


static void  Free_ContextPos1( HB_ContextPosFormat1*  cpf1 )
{
  HB_UShort        n, count;

  HB_PosRuleSet*  prs;


  if ( cpf1->PosRuleSet )
  {
    count = cpf1->PosRuleSetCount;
    prs   = cpf1->PosRuleSet;

    for ( n = 0; n < count; n++ )
      Free_PosRuleSet( &prs[n] );

    FREE( prs );
  }

  _HB_OPEN_Free_Coverage( &cpf1->Coverage );
}


/* PosClassRule */

static HB_Error  Load_PosClassRule( HB_ContextPosFormat2*  cpf2,
				    HB_PosClassRule*       pcr,
				    HB_Stream               stream )
{
  HB_Error  error;

  HB_UShort             n, count;

  HB_UShort*            c;
  HB_PosLookupRecord*  plr;


  if ( ACCESS_Frame( 4L ) )
    return error;

  pcr->GlyphCount = GET_UShort();
  pcr->PosCount   = GET_UShort();

  FORGET_Frame();

  if ( pcr->GlyphCount > cpf2->MaxContextLength )
    cpf2->MaxContextLength = pcr->GlyphCount;

  pcr->Class = NULL;

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

  if ( ALLOC_ARRAY( pcr->Class, count, HB_UShort ) )
    return error;

  c = pcr->Class;

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

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

  FORGET_Frame();

  pcr->PosLookupRecord = NULL;

  count = pcr->PosCount;

  if ( ALLOC_ARRAY( pcr->PosLookupRecord, count, HB_PosLookupRecord ) )
    goto Fail2;

  plr = pcr->PosLookupRecord;

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

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

  FORGET_Frame();

  return HB_Err_Ok;

Fail1:
  FREE( plr );

Fail2:
  FREE( c );
  return error;
}


static void  Free_PosClassRule( HB_PosClassRule*  pcr )
{
  FREE( pcr->PosLookupRecord );
  FREE( pcr->Class );
}


/* PosClassSet */

static HB_Error  Load_PosClassSet( HB_ContextPosFormat2*  cpf2,
				   HB_PosClassSet*        pcs,
				   HB_Stream               stream )
{
  HB_Error  error;

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

  HB_PosClassRule*  pcr;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = pcs->PosClassRuleCount = GET_UShort();

  FORGET_Frame();

  pcs->PosClassRule = NULL;

  if ( ALLOC_ARRAY( pcs->PosClassRule, count, HB_PosClassRule ) )
    return error;

  pcr = pcs->PosClassRule;

  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_PosClassRule( cpf2, &pcr[n],
				      stream ) ) != HB_Err_Ok )
      goto Fail;
    (void)FILE_Seek( cur_offset );
  }

  return HB_Err_Ok;

Fail:
  for ( m = 0; m < n; m++ )
    Free_PosClassRule( &pcr[m] );

  FREE( pcr );
  return error;
}


static void  Free_PosClassSet( HB_PosClassSet*  pcs )
{
  HB_UShort          n, count;

  HB_PosClassRule*  pcr;


  if ( pcs->PosClassRule )
  {
    count = pcs->PosClassRuleCount;
    pcr   = pcs->PosClassRule;

    for ( n = 0; n < count; n++ )
      Free_PosClassRule( &pcr[n] );

    FREE( pcr );
  }
}


/* ContextPosFormat2 */

static HB_Error  Load_ContextPos2( HB_ContextPosFormat2*  cpf2,
				   HB_Stream               stream )
{
  HB_Error  error;

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

  HB_PosClassSet*  pcs;


  base_offset = FILE_Pos() - 2;

  if ( ACCESS_Frame( 2L ) )
    return error;

  new_offset = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_Coverage( &cpf2->Coverage, stream ) ) != HB_Err_Ok )
    return error;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 4L ) )
    goto Fail3;

  new_offset = GET_UShort() + base_offset;

  /* `PosClassSetCount' is the upper limit for class values, thus we
     read it now to make an additional safety check.                 */

  count = cpf2->PosClassSetCount = GET_UShort();

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_ClassDefinition( &cpf2->ClassDef, count,
				       stream ) ) != HB_Err_Ok )
    goto Fail3;
  (void)FILE_Seek( cur_offset );

  cpf2->PosClassSet      = NULL;
  cpf2->MaxContextLength = 0;

  if ( ALLOC_ARRAY( cpf2->PosClassSet, count, HB_PosClassSet ) )
    goto Fail2;

  pcs = cpf2->PosClassSet;

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

    new_offset = GET_UShort() + base_offset;

    FORGET_Frame();

    if ( new_offset != base_offset )      /* not a NULL offset */
    {
      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = Load_PosClassSet( cpf2, &pcs[n],
				       stream ) ) != HB_Err_Ok )
	goto Fail1;
      (void)FILE_Seek( cur_offset );
    }
    else
    {
      /* we create a PosClassSet table with no entries */

      cpf2->PosClassSet[n].PosClassRuleCount = 0;
      cpf2->PosClassSet[n].PosClassRule      = NULL;
    }
  }

  return HB_Err_Ok;

Fail1:
  for ( m = 0; m < n; n++ )
    Free_PosClassSet( &pcs[m] );

  FREE( pcs );

Fail2:
  _HB_OPEN_Free_ClassDefinition( &cpf2->ClassDef );

Fail3:
  _HB_OPEN_Free_Coverage( &cpf2->Coverage );
  return error;
}


static void  Free_ContextPos2( HB_ContextPosFormat2*  cpf2 )
{
  HB_UShort         n, count;

  HB_PosClassSet*  pcs;


  if ( cpf2->PosClassSet )
  {
    count = cpf2->PosClassSetCount;
    pcs   = cpf2->PosClassSet;

    for ( n = 0; n < count; n++ )
      Free_PosClassSet( &pcs[n] );

    FREE( pcs );
  }

  _HB_OPEN_Free_ClassDefinition( &cpf2->ClassDef );
  _HB_OPEN_Free_Coverage( &cpf2->Coverage );
}


/* ContextPosFormat3 */

static HB_Error  Load_ContextPos3( HB_ContextPosFormat3*  cpf3,
				   HB_Stream               stream )
{
  HB_Error  error;

  HB_UShort             n, count;
  HB_UInt              cur_offset, new_offset, base_offset;

  HB_Coverage*         c;
  HB_PosLookupRecord*  plr;


  base_offset = FILE_Pos() - 2L;

  if ( ACCESS_Frame( 4L ) )
    return error;

  cpf3->GlyphCount = GET_UShort();
  cpf3->PosCount   = GET_UShort();

  FORGET_Frame();

  cpf3->Coverage = NULL;

  count = cpf3->GlyphCount;

  if ( ALLOC_ARRAY( cpf3->Coverage, count, HB_Coverage ) )
    return error;

  c = cpf3->Coverage;

  for ( n = 0; n < count; n++ )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail2;

    new_offset = GET_UShort() + base_offset;

    FORGET_Frame();

    cur_offset = FILE_Pos();
    if ( FILE_Seek( new_offset ) ||
	 ( error = _HB_OPEN_Load_Coverage( &c[n], stream ) ) != HB_Err_Ok )
      goto Fail2;
    (void)FILE_Seek( cur_offset );
  }

  cpf3->PosLookupRecord = NULL;

  count = cpf3->PosCount;

  if ( ALLOC_ARRAY( cpf3->PosLookupRecord, count, HB_PosLookupRecord ) )
    goto Fail2;

  plr = cpf3->PosLookupRecord;

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

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

  FORGET_Frame();

  return HB_Err_Ok;

Fail1:
  FREE( plr );

Fail2:
  for ( n = 0; n < count; n++ )
    _HB_OPEN_Free_Coverage( &c[n] );

  FREE( c );
  return error;
}


static void  Free_ContextPos3( HB_ContextPosFormat3*  cpf3 )
{
  HB_UShort      n, count;

  HB_Coverage*  c;


  FREE( cpf3->PosLookupRecord );

  if ( cpf3->Coverage )
  {
    count = cpf3->GlyphCount;
    c     = cpf3->Coverage;

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

    FREE( c );
  }
}


/* ContextPos */

static HB_Error  Load_ContextPos( HB_GPOS_SubTable* st,
				  HB_Stream        stream )
{
  HB_Error  error;
  HB_ContextPos*   cp = &st->context;


  if ( ACCESS_Frame( 2L ) )
    return error;

  cp->PosFormat = GET_UShort();

  FORGET_Frame();

  switch ( cp->PosFormat )
  {
  case 1:
    return Load_ContextPos1( &cp->cpf.cpf1, stream );

  case 2:
    return Load_ContextPos2( &cp->cpf.cpf2, stream );

  case 3:
    return Load_ContextPos3( &cp->cpf.cpf3, stream );

  default:
    return ERR(HB_Err_Invalid_SubTable_Format);
  }

  return HB_Err_Ok;               /* never reached */
}


static void  Free_ContextPos( HB_GPOS_SubTable* st )
{
  HB_ContextPos*   cp = &st->context;

  switch ( cp->PosFormat )
  {
  case 1:  Free_ContextPos1( &cp->cpf.cpf1 ); break;
  case 2:  Free_ContextPos2( &cp->cpf.cpf2 ); break;
  case 3:  Free_ContextPos3( &cp->cpf.cpf3 ); break;
  default:					      break;
  }
}


static HB_Error  Lookup_ContextPos1( GPOS_Instance*          gpi,
				     HB_ContextPosFormat1*  cpf1,
				     HB_Buffer              buffer,
				     HB_UShort               flags,
				     HB_UShort               context_length,
				     int                     nesting_level )
{
  HB_UShort        index, property;
  HB_UShort        i, j, k, numpr;
  HB_Error         error;
  HB_GPOSHeader*  gpos = gpi->gpos;

  HB_PosRule*     pr;
  hb_ot_layout_t*  layout;


  layout = gpos->layout;

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

  error = _HB_OPEN_Coverage_Index( &cpf1->Coverage, IN_CURGLYPH(), &index );
  if ( error )
    return error;

  pr    = cpf1->PosRuleSet[index].PosRule;
  numpr = cpf1->PosRuleSet[index].PosRuleCount;

  for ( k = 0; k < numpr; k++ )
  {
    if ( context_length != 0xFFFF && context_length < pr[k].GlyphCount )
      goto next_posrule;

    if ( buffer->in_pos + pr[k].GlyphCount > buffer->in_length )
      goto next_posrule;                       /* context is too long */

    for ( i = 1, j = buffer->in_pos + 1; i < pr[k].GlyphCount; i++, j++ )
    {
      while ( CHECK_Property( layout, IN_ITEM( j ), flags, &property ) )
      {
	if ( error && error != HB_Err_Not_Covered )
	  return error;

	if ( j + pr[k].GlyphCount - i == (HB_Int)buffer->in_length )
	  goto next_posrule;
	j++;
      }

      if ( IN_GLYPH( j ) != pr[k].Input[i - 1] )
	goto next_posrule;
    }

    return Do_ContextPos( gpi, pr[k].GlyphCount,
			  pr[k].PosCount, pr[k].PosLookupRecord,
			  buffer,
			  nesting_level );

    next_posrule:
      ;
  }

  return HB_Err_Not_Covered;
}


static HB_Error  Lookup_ContextPos2( GPOS_Instance*          gpi,
				     HB_ContextPosFormat2*  cpf2,
				     HB_Buffer              buffer,
				     HB_UShort               flags,
				     HB_UShort               context_length,
				     int                     nesting_level )
{
  HB_UShort          index, property;
  HB_Error           error;
  HB_UShort          i, j, k, known_classes;

  HB_UShort*         classes;
  HB_UShort*         cl;
  HB_GPOSHeader*    gpos = gpi->gpos;

  HB_PosClassSet*   pcs;
  HB_PosClassRule*  pr;
  hb_ot_layout_t*    layout;


  layout = gpos->layout;

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

  /* Note: The coverage table in format 2 doesn't give an index into
	   anything.  It just lets us know whether or not we need to
	   do any lookup at all.                                     */

  error = _HB_OPEN_Coverage_Index( &cpf2->Coverage, IN_CURGLYPH(), &index );
  if ( error )
    return error;

  if (cpf2->MaxContextLength < 1)
    return HB_Err_Not_Covered;

  if ( ALLOC_ARRAY( classes, cpf2->MaxContextLength, HB_UShort ) )
    return error;

  error = _HB_OPEN_Get_Class( &cpf2->ClassDef, IN_CURGLYPH(),
		     &classes[0], NULL );
  if ( error && error != HB_Err_Not_Covered )
    goto End;
  known_classes = 0;

  pcs = &cpf2->PosClassSet[classes[0]];
  if ( !pcs )
  {
    error = ERR(HB_Err_Invalid_SubTable);
    goto End;
  }

  for ( k = 0; k < pcs->PosClassRuleCount; k++ )
  {
    pr = &pcs->PosClassRule[k];

    if ( context_length != 0xFFFF && context_length < pr->GlyphCount )
      goto next_posclassrule;

    if ( buffer->in_pos + pr->GlyphCount > buffer->in_length )
      goto next_posclassrule;                /* context is too long */

    cl   = pr->Class;

    /* Start at 1 because [0] is implied */

    for ( i = 1, j = buffer->in_pos + 1; i < pr->GlyphCount; i++, j++ )
    {
      while ( CHECK_Property( layout, IN_ITEM( j ), flags, &property ) )
      {
	if ( error && error != HB_Err_Not_Covered )
	  goto End;

	if ( j + pr->GlyphCount - i == (HB_Int)buffer->in_length )
	  goto next_posclassrule;
	j++;
      }

      if ( i > known_classes )
      {
	/* Keeps us from having to do this for each rule */

	error = _HB_OPEN_Get_Class( &cpf2->ClassDef, IN_GLYPH( j ), &classes[i], NULL );
	if ( error && error != HB_Err_Not_Covered )
	  goto End;
	known_classes = i;
      }

      if ( cl[i - 1] != classes[i] )
	goto next_posclassrule;
    }

    error = Do_ContextPos( gpi, pr->GlyphCount,
			   pr->PosCount, pr->PosLookupRecord,
			   buffer,
			   nesting_level );
    goto End;

  next_posclassrule:
    ;
  }

  error = HB_Err_Not_Covered;

End:
  FREE( classes );
  return error;
}


static HB_Error  Lookup_ContextPos3( GPOS_Instance*          gpi,
				     HB_ContextPosFormat3*  cpf3,
				     HB_Buffer              buffer,
				     HB_UShort               flags,
				     HB_UShort               context_length,
				     int                     nesting_level )
{
  HB_Error         error;
  HB_UShort        index, i, j, property;
  HB_GPOSHeader*  gpos = gpi->gpos;

  HB_Coverage*    c;
  hb_ot_layout_t*  layout;


  layout = gpos->layout;

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

  if ( context_length != 0xFFFF && context_length < cpf3->GlyphCount )
    return HB_Err_Not_Covered;

  if ( buffer->in_pos + cpf3->GlyphCount > buffer->in_length )
    return HB_Err_Not_Covered;         /* context is too long */

  c    = cpf3->Coverage;

  for ( i = 1, j = 1; i < cpf3->GlyphCount; i++, j++ )
  {
    while ( CHECK_Property( layout, IN_ITEM( j ), flags, &property ) )
    {
      if ( error && error != HB_Err_Not_Covered )
	return error;

      if ( j + cpf3->GlyphCount - i == (HB_Int)buffer->in_length )
	return HB_Err_Not_Covered;
      j++;
    }

    error = _HB_OPEN_Coverage_Index( &c[i], IN_GLYPH( j ), &index );
    if ( error )
      return error;
  }

  return Do_ContextPos( gpi, cpf3->GlyphCount,
			cpf3->PosCount, cpf3->PosLookupRecord,
			buffer,
			nesting_level );
}


static HB_Error  Lookup_ContextPos( GPOS_Instance*    gpi,
				    HB_GPOS_SubTable* st,
				    HB_Buffer        buffer,
				    HB_UShort         flags,
				    HB_UShort         context_length,
				    int               nesting_level )
{
  HB_ContextPos*   cp = &st->context;

  switch ( cp->PosFormat )
  {
  case 1:
    return Lookup_ContextPos1( gpi, &cp->cpf.cpf1, buffer,
			       flags, context_length, nesting_level );

  case 2:
    return Lookup_ContextPos2( gpi, &cp->cpf.cpf2, buffer,
			       flags, context_length, nesting_level );

  case 3:
    return Lookup_ContextPos3( gpi, &cp->cpf.cpf3, buffer,
			       flags, context_length, nesting_level );

  default:
    return ERR(HB_Err_Invalid_SubTable_Format);
  }

  return HB_Err_Ok;               /* never reached */
}


/* LookupType 8 */

/* ChainPosRule */

static HB_Error  Load_ChainPosRule( HB_ChainPosRule*  cpr,
				    HB_Stream          stream )
{
  HB_Error  error;

  HB_UShort             n, count;
  HB_UShort*            b;
  HB_UShort*            i;
  HB_UShort*            l;

  HB_PosLookupRecord*  plr;


  if ( ACCESS_Frame( 2L ) )
    return error;

  cpr->BacktrackGlyphCount = GET_UShort();

  FORGET_Frame();

  cpr->Backtrack = NULL;

  count = cpr->BacktrackGlyphCount;

  if ( ALLOC_ARRAY( cpr->Backtrack, count, HB_UShort ) )
    return error;

  b = cpr->Backtrack;

  if ( ACCESS_Frame( count * 2L ) )
    goto Fail4;

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

  FORGET_Frame();

  if ( ACCESS_Frame( 2L ) )
    goto Fail4;

  cpr->InputGlyphCount = GET_UShort();

  FORGET_Frame();

  cpr->Input = NULL;

  count = cpr->InputGlyphCount - 1;  /* only InputGlyphCount - 1 elements */

  if ( ALLOC_ARRAY( cpr->Input, count, HB_UShort ) )
    goto Fail4;

  i = cpr->Input;

  if ( ACCESS_Frame( count * 2L ) )
    goto Fail3;

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

  FORGET_Frame();

  if ( ACCESS_Frame( 2L ) )
    goto Fail3;

  cpr->LookaheadGlyphCount = GET_UShort();

  FORGET_Frame();

  cpr->Lookahead = NULL;

  count = cpr->LookaheadGlyphCount;

  if ( ALLOC_ARRAY( cpr->Lookahead, count, HB_UShort ) )
    goto Fail3;

  l = cpr->Lookahead;

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

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

  FORGET_Frame();

  if ( ACCESS_Frame( 2L ) )
    goto Fail2;

  cpr->PosCount = GET_UShort();

  FORGET_Frame();

  cpr->PosLookupRecord = NULL;

  count = cpr->PosCount;

  if ( ALLOC_ARRAY( cpr->PosLookupRecord, count, HB_PosLookupRecord ) )
    goto Fail2;

  plr = cpr->PosLookupRecord;

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

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

  FORGET_Frame();

  return HB_Err_Ok;

Fail1:
  FREE( plr );

Fail2:
  FREE( l );

Fail3:
  FREE( i );

Fail4:
  FREE( b );
  return error;
}


static void  Free_ChainPosRule( HB_ChainPosRule*  cpr )
{
  FREE( cpr->PosLookupRecord );
  FREE( cpr->Lookahead );
  FREE( cpr->Input );
  FREE( cpr->Backtrack );
}


/* ChainPosRuleSet */

static HB_Error  Load_ChainPosRuleSet( HB_ChainPosRuleSet*  cprs,
				       HB_Stream             stream )
{
  HB_Error  error;

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

  HB_ChainPosRule*  cpr;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = cprs->ChainPosRuleCount = GET_UShort();

  FORGET_Frame();

  cprs->ChainPosRule = NULL;

  if ( ALLOC_ARRAY( cprs->ChainPosRule, count, HB_ChainPosRule ) )
    return error;

  cpr = cprs->ChainPosRule;

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

  return HB_Err_Ok;

Fail:
  for ( m = 0; m < n; m++ )
    Free_ChainPosRule( &cpr[m] );

  FREE( cpr );
  return error;
}


static void  Free_ChainPosRuleSet( HB_ChainPosRuleSet*  cprs )
{
  HB_UShort          n, count;

  HB_ChainPosRule*  cpr;


  if ( cprs->ChainPosRule )
  {
    count = cprs->ChainPosRuleCount;
    cpr   = cprs->ChainPosRule;

    for ( n = 0; n < count; n++ )
      Free_ChainPosRule( &cpr[n] );

    FREE( cpr );
  }
}


/* ChainContextPosFormat1 */

static HB_Error  Load_ChainContextPos1( HB_ChainContextPosFormat1*  ccpf1,
					HB_Stream                    stream )
{
  HB_Error  error;

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

  HB_ChainPosRuleSet*  cprs;


  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 = _HB_OPEN_Load_Coverage( &ccpf1->Coverage, stream ) ) != HB_Err_Ok )
    return error;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 2L ) )
    goto Fail2;

  count = ccpf1->ChainPosRuleSetCount = GET_UShort();

  FORGET_Frame();

  ccpf1->ChainPosRuleSet = NULL;

  if ( ALLOC_ARRAY( ccpf1->ChainPosRuleSet, count, HB_ChainPosRuleSet ) )
    goto Fail2;

  cprs = ccpf1->ChainPosRuleSet;

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

  return HB_Err_Ok;

Fail1:
  for ( m = 0; m < n; m++ )
    Free_ChainPosRuleSet( &cprs[m] );

  FREE( cprs );

Fail2:
  _HB_OPEN_Free_Coverage( &ccpf1->Coverage );
  return error;
}


static void  Free_ChainContextPos1( HB_ChainContextPosFormat1*  ccpf1 )
{
  HB_UShort             n, count;

  HB_ChainPosRuleSet*  cprs;


  if ( ccpf1->ChainPosRuleSet )
  {
    count = ccpf1->ChainPosRuleSetCount;
    cprs  = ccpf1->ChainPosRuleSet;

    for ( n = 0; n < count; n++ )
      Free_ChainPosRuleSet( &cprs[n] );

    FREE( cprs );
  }

  _HB_OPEN_Free_Coverage( &ccpf1->Coverage );
}


/* ChainPosClassRule */

static HB_Error  Load_ChainPosClassRule(
		   HB_ChainContextPosFormat2*  ccpf2,
		   HB_ChainPosClassRule*       cpcr,
		   HB_Stream                    stream )
{
  HB_Error  error;

  HB_UShort             n, count;

  HB_UShort*            b;
  HB_UShort*            i;
  HB_UShort*            l;
  HB_PosLookupRecord*  plr;


  if ( ACCESS_Frame( 2L ) )
    return error;

  cpcr->BacktrackGlyphCount = GET_UShort();

  FORGET_Frame();

  if ( cpcr->BacktrackGlyphCount > ccpf2->MaxBacktrackLength )
    ccpf2->MaxBacktrackLength = cpcr->BacktrackGlyphCount;

  cpcr->Backtrack = NULL;

  count = cpcr->BacktrackGlyphCount;

  if ( ALLOC_ARRAY( cpcr->Backtrack, count, HB_UShort ) )
    return error;

  b = cpcr->Backtrack;

  if ( ACCESS_Frame( count * 2L ) )
    goto Fail4;

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

  FORGET_Frame();

  if ( ACCESS_Frame( 2L ) )
    goto Fail4;

  cpcr->InputGlyphCount = GET_UShort();

  if ( cpcr->InputGlyphCount > ccpf2->MaxInputLength )
    ccpf2->MaxInputLength = cpcr->InputGlyphCount;

  FORGET_Frame();

  cpcr->Input = NULL;

  count = cpcr->InputGlyphCount - 1; /* only InputGlyphCount - 1 elements */

  if ( ALLOC_ARRAY( cpcr->Input, count, HB_UShort ) )
    goto Fail4;

  i = cpcr->Input;

  if ( ACCESS_Frame( count * 2L ) )
    goto Fail3;

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

  FORGET_Frame();

  if ( ACCESS_Frame( 2L ) )
    goto Fail3;

  cpcr->LookaheadGlyphCount = GET_UShort();

  FORGET_Frame();

  if ( cpcr->LookaheadGlyphCount > ccpf2->MaxLookaheadLength )
    ccpf2->MaxLookaheadLength = cpcr->LookaheadGlyphCount;

  cpcr->Lookahead = NULL;

  count = cpcr->LookaheadGlyphCount;

  if ( ALLOC_ARRAY( cpcr->Lookahead, count, HB_UShort ) )
    goto Fail3;

  l = cpcr->Lookahead;

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

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

  FORGET_Frame();

  if ( ACCESS_Frame( 2L ) )
    goto Fail2;

  cpcr->PosCount = GET_UShort();

  FORGET_Frame();

  cpcr->PosLookupRecord = NULL;

  count = cpcr->PosCount;

  if ( ALLOC_ARRAY( cpcr->PosLookupRecord, count, HB_PosLookupRecord ) )
    goto Fail2;

  plr = cpcr->PosLookupRecord;

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

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

  FORGET_Frame();

  return HB_Err_Ok;

Fail1:
  FREE( plr );

Fail2:
  FREE( l );

Fail3:
  FREE( i );

Fail4:
  FREE( b );
  return error;
}


static void  Free_ChainPosClassRule( HB_ChainPosClassRule*  cpcr )
{
  FREE( cpcr->PosLookupRecord );
  FREE( cpcr->Lookahead );
  FREE( cpcr->Input );
  FREE( cpcr->Backtrack );
}


/* PosClassSet */

static HB_Error  Load_ChainPosClassSet(
		   HB_ChainContextPosFormat2*  ccpf2,
		   HB_ChainPosClassSet*        cpcs,
		   HB_Stream                    stream )
{
  HB_Error  error;

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

  HB_ChainPosClassRule*  cpcr;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  count = cpcs->ChainPosClassRuleCount = GET_UShort();

  FORGET_Frame();

  cpcs->ChainPosClassRule = NULL;

  if ( ALLOC_ARRAY( cpcs->ChainPosClassRule, count,
		    HB_ChainPosClassRule ) )
    return error;

  cpcr = cpcs->ChainPosClassRule;

  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_ChainPosClassRule( ccpf2, &cpcr[n],
					   stream ) ) != HB_Err_Ok )
      goto Fail;
    (void)FILE_Seek( cur_offset );
  }

  return HB_Err_Ok;

Fail:
  for ( m = 0; m < n; m++ )
    Free_ChainPosClassRule( &cpcr[m] );

  FREE( cpcr );
  return error;
}


static void  Free_ChainPosClassSet( HB_ChainPosClassSet*  cpcs )
{
  HB_UShort               n, count;

  HB_ChainPosClassRule*  cpcr;


  if ( cpcs->ChainPosClassRule )
  {
    count = cpcs->ChainPosClassRuleCount;
    cpcr  = cpcs->ChainPosClassRule;

    for ( n = 0; n < count; n++ )
      Free_ChainPosClassRule( &cpcr[n] );

    FREE( cpcr );
  }
}


/* ChainContextPosFormat2 */

static HB_Error  Load_ChainContextPos2( HB_ChainContextPosFormat2*  ccpf2,
					HB_Stream                    stream )
{
  HB_Error  error;

  HB_UShort              n, m, count;
  HB_UInt               cur_offset, new_offset, base_offset;
  HB_UInt               backtrack_offset, input_offset, lookahead_offset;

  HB_ChainPosClassSet*  cpcs;


  base_offset = FILE_Pos() - 2;

  if ( ACCESS_Frame( 2L ) )
    return error;

  new_offset = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_Coverage( &ccpf2->Coverage, stream ) ) != HB_Err_Ok )
    return error;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 8L ) )
    goto Fail5;

  backtrack_offset = GET_UShort();
  input_offset     = GET_UShort();
  lookahead_offset = GET_UShort();

  /* `ChainPosClassSetCount' is the upper limit for input class values,
     thus we read it now to make an additional safety check. No limit
     is known or needed for the other two class definitions          */

  count = ccpf2->ChainPosClassSetCount = GET_UShort();

  FORGET_Frame();

  if ( ( error = _HB_OPEN_Load_EmptyOrClassDefinition( &ccpf2->BacktrackClassDef, 65535,
						       backtrack_offset, base_offset,
						       stream ) ) != HB_Err_Ok )
    goto Fail5;
  if ( ( error = _HB_OPEN_Load_EmptyOrClassDefinition( &ccpf2->InputClassDef, count,
						       input_offset, base_offset,
						       stream ) ) != HB_Err_Ok )
    goto Fail4;
  if ( ( error = _HB_OPEN_Load_EmptyOrClassDefinition( &ccpf2->LookaheadClassDef, 65535,
						       lookahead_offset, base_offset,
						       stream ) ) != HB_Err_Ok )
    goto Fail3;

  ccpf2->ChainPosClassSet   = NULL;
  ccpf2->MaxBacktrackLength = 0;
  ccpf2->MaxInputLength     = 0;
  ccpf2->MaxLookaheadLength = 0;

  if ( ALLOC_ARRAY( ccpf2->ChainPosClassSet, count, HB_ChainPosClassSet ) )
    goto Fail2;

  cpcs = ccpf2->ChainPosClassSet;

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

    new_offset = GET_UShort() + base_offset;

    FORGET_Frame();

    if ( new_offset != base_offset )      /* not a NULL offset */
    {
      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = Load_ChainPosClassSet( ccpf2, &cpcs[n],
					    stream ) ) != HB_Err_Ok )
	goto Fail1;
      (void)FILE_Seek( cur_offset );
    }
    else
    {
      /* we create a ChainPosClassSet table with no entries */

      ccpf2->ChainPosClassSet[n].ChainPosClassRuleCount = 0;
      ccpf2->ChainPosClassSet[n].ChainPosClassRule      = NULL;
    }
  }

  return HB_Err_Ok;

Fail1:
  for ( m = 0; m < n; m++ )
    Free_ChainPosClassSet( &cpcs[m] );

  FREE( cpcs );

Fail2:
  _HB_OPEN_Free_ClassDefinition( &ccpf2->LookaheadClassDef );

Fail3:
  _HB_OPEN_Free_ClassDefinition( &ccpf2->InputClassDef );

Fail4:
  _HB_OPEN_Free_ClassDefinition( &ccpf2->BacktrackClassDef );

Fail5:
  _HB_OPEN_Free_Coverage( &ccpf2->Coverage );
  return error;
}


static void  Free_ChainContextPos2( HB_ChainContextPosFormat2*  ccpf2 )
{
  HB_UShort              n, count;

  HB_ChainPosClassSet*  cpcs;


  if ( ccpf2->ChainPosClassSet )
  {
    count = ccpf2->ChainPosClassSetCount;
    cpcs  = ccpf2->ChainPosClassSet;

    for ( n = 0; n < count; n++ )
      Free_ChainPosClassSet( &cpcs[n] );

    FREE( cpcs );
  }

  _HB_OPEN_Free_ClassDefinition( &ccpf2->LookaheadClassDef );
  _HB_OPEN_Free_ClassDefinition( &ccpf2->InputClassDef );
  _HB_OPEN_Free_ClassDefinition( &ccpf2->BacktrackClassDef );

  _HB_OPEN_Free_Coverage( &ccpf2->Coverage );
}


/* ChainContextPosFormat3 */

static HB_Error  Load_ChainContextPos3( HB_ChainContextPosFormat3*  ccpf3,
					HB_Stream                    stream )
{
  HB_Error  error;

  HB_UShort             n, nb, ni, nl, m, count;
  HB_UShort             backtrack_count, input_count, lookahead_count;
  HB_UInt              cur_offset, new_offset, base_offset;

  HB_Coverage*         b;
  HB_Coverage*         i;
  HB_Coverage*         l;
  HB_PosLookupRecord*  plr;


  base_offset = FILE_Pos() - 2L;

  if ( ACCESS_Frame( 2L ) )
    return error;

  ccpf3->BacktrackGlyphCount = GET_UShort();

  FORGET_Frame();

  ccpf3->BacktrackCoverage = NULL;

  backtrack_count = ccpf3->BacktrackGlyphCount;

  if ( ALLOC_ARRAY( ccpf3->BacktrackCoverage, backtrack_count,
		    HB_Coverage ) )
    return error;

  b = ccpf3->BacktrackCoverage;

  for ( nb = 0; nb < backtrack_count; nb++ )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail4;

    new_offset = GET_UShort() + base_offset;

    FORGET_Frame();

    cur_offset = FILE_Pos();
    if ( FILE_Seek( new_offset ) ||
	 ( error = _HB_OPEN_Load_Coverage( &b[nb], stream ) ) != HB_Err_Ok )
      goto Fail4;
    (void)FILE_Seek( cur_offset );
  }

  if ( ACCESS_Frame( 2L ) )
    goto Fail4;

  ccpf3->InputGlyphCount = GET_UShort();

  FORGET_Frame();

  ccpf3->InputCoverage = NULL;

  input_count = ccpf3->InputGlyphCount;

  if ( ALLOC_ARRAY( ccpf3->InputCoverage, input_count, HB_Coverage ) )
    goto Fail4;

  i = ccpf3->InputCoverage;

  for ( ni = 0; ni < input_count; ni++ )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail3;

    new_offset = GET_UShort() + base_offset;

    FORGET_Frame();

    cur_offset = FILE_Pos();
    if ( FILE_Seek( new_offset ) ||
	 ( error = _HB_OPEN_Load_Coverage( &i[ni], stream ) ) != HB_Err_Ok )
      goto Fail3;
    (void)FILE_Seek( cur_offset );
  }

  if ( ACCESS_Frame( 2L ) )
    goto Fail3;

  ccpf3->LookaheadGlyphCount = GET_UShort();

  FORGET_Frame();

  ccpf3->LookaheadCoverage = NULL;

  lookahead_count = ccpf3->LookaheadGlyphCount;

  if ( ALLOC_ARRAY( ccpf3->LookaheadCoverage, lookahead_count,
		    HB_Coverage ) )
    goto Fail3;

  l = ccpf3->LookaheadCoverage;

  for ( nl = 0; nl < lookahead_count; nl++ )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail2;

    new_offset = GET_UShort() + base_offset;

    FORGET_Frame();

    cur_offset = FILE_Pos();
    if ( FILE_Seek( new_offset ) ||
	 ( error = _HB_OPEN_Load_Coverage( &l[nl], stream ) ) != HB_Err_Ok )
      goto Fail2;
    (void)FILE_Seek( cur_offset );
  }

  if ( ACCESS_Frame( 2L ) )
    goto Fail2;

  ccpf3->PosCount = GET_UShort();

  FORGET_Frame();

  ccpf3->PosLookupRecord = NULL;

  count = ccpf3->PosCount;

  if ( ALLOC_ARRAY( ccpf3->PosLookupRecord, count, HB_PosLookupRecord ) )
    goto Fail2;

  plr = ccpf3->PosLookupRecord;

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

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

  FORGET_Frame();

  return HB_Err_Ok;

Fail1:
  FREE( plr );

Fail2:
  for ( m = 0; m < nl; m++ )
    _HB_OPEN_Free_Coverage( &l[m] );

  FREE( l );

Fail3:
  for ( m = 0; m < ni; m++ )
    _HB_OPEN_Free_Coverage( &i[m] );

  FREE( i );

Fail4:
  for ( m = 0; m < nb; m++ )
    _HB_OPEN_Free_Coverage( &b[m] );

  FREE( b );
  return error;
}


static void  Free_ChainContextPos3( HB_ChainContextPosFormat3*  ccpf3 )
{
  HB_UShort      n, count;

  HB_Coverage*  c;


  FREE( ccpf3->PosLookupRecord );

  if ( ccpf3->LookaheadCoverage )
  {
    count = ccpf3->LookaheadGlyphCount;
    c     = ccpf3->LookaheadCoverage;

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

    FREE( c );
  }

  if ( ccpf3->InputCoverage )
  {
    count = ccpf3->InputGlyphCount;
    c     = ccpf3->InputCoverage;

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

    FREE( c );
  }

  if ( ccpf3->BacktrackCoverage )
  {
    count = ccpf3->BacktrackGlyphCount;
    c     = ccpf3->BacktrackCoverage;

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

    FREE( c );
  }
}


/* ChainContextPos */

static HB_Error  Load_ChainContextPos( HB_GPOS_SubTable* st,
				       HB_Stream             stream )
{
  HB_Error  error;
  HB_ChainContextPos*  ccp = &st->chain;


  if ( ACCESS_Frame( 2L ) )
    return error;

  ccp->PosFormat = GET_UShort();

  FORGET_Frame();

  switch ( ccp->PosFormat )
  {
  case 1:
    return Load_ChainContextPos1( &ccp->ccpf.ccpf1, stream );

  case 2:
    return Load_ChainContextPos2( &ccp->ccpf.ccpf2, stream );

  case 3:
    return Load_ChainContextPos3( &ccp->ccpf.ccpf3, stream );

  default:
    return ERR(HB_Err_Invalid_SubTable_Format);
  }

  return HB_Err_Ok;               /* never reached */
}


static void  Free_ChainContextPos( HB_GPOS_SubTable* st )
{
  HB_ChainContextPos*  ccp = &st->chain;

  switch ( ccp->PosFormat )
  {
  case 1:  Free_ChainContextPos1( &ccp->ccpf.ccpf1 ); break;
  case 2:  Free_ChainContextPos2( &ccp->ccpf.ccpf2 ); break;
  case 3:  Free_ChainContextPos3( &ccp->ccpf.ccpf3 ); break;
  default:						      break;
  }
}


static HB_Error  Lookup_ChainContextPos1(
		   GPOS_Instance*               gpi,
		   HB_ChainContextPosFormat1*  ccpf1,
		   HB_Buffer                   buffer,
		   HB_UShort                    flags,
		   HB_UShort                    context_length,
		   int                          nesting_level )
{
  HB_UShort          index, property;
  HB_UShort          i, j, k, num_cpr;
  HB_UShort          bgc, igc, lgc;
  HB_Error           error;
  HB_GPOSHeader*    gpos = gpi->gpos;

  HB_ChainPosRule*  cpr;
  HB_ChainPosRule   curr_cpr;
  hb_ot_layout_t*    layout;


  layout = gpos->layout;

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

  error = _HB_OPEN_Coverage_Index( &ccpf1->Coverage, IN_CURGLYPH(), &index );
  if ( error )
    return error;

  cpr     = ccpf1->ChainPosRuleSet[index].ChainPosRule;
  num_cpr = ccpf1->ChainPosRuleSet[index].ChainPosRuleCount;

  for ( k = 0; k < num_cpr; k++ )
  {
    curr_cpr = cpr[k];
    bgc      = curr_cpr.BacktrackGlyphCount;
    igc      = curr_cpr.InputGlyphCount;
    lgc      = curr_cpr.LookaheadGlyphCount;

    if ( context_length != 0xFFFF && context_length < igc )
      goto next_chainposrule;

    /* check whether context is too long; it is a first guess only */

    if ( bgc > buffer->in_pos || buffer->in_pos + igc + lgc > buffer->in_length )
      goto next_chainposrule;

    if ( bgc )
    {
      /* Since we don't know in advance the number of glyphs to inspect,
	 we search backwards for matches in the backtrack glyph array    */

      for ( i = 0, j = buffer->in_pos - 1; i < bgc; i++, j-- )
      {
	while ( CHECK_Property( layout, IN_ITEM( j ), flags, &property ) )
	{
	  if ( error && error != HB_Err_Not_Covered )
	    return error;

	  if ( j + 1 == bgc - i )
	    goto next_chainposrule;
	  j--;
	}

	/* In OpenType 1.3, it is undefined whether the offsets of
	   backtrack glyphs is in logical order or not.  Version 1.4
	   will clarify this:

	     Logical order -      a  b  c  d  e  f  g  h  i  j
					      i
	     Input offsets -                  0  1
	     Backtrack offsets -  3  2  1  0
	     Lookahead offsets -                    0  1  2  3           */

	if ( IN_GLYPH( j ) != curr_cpr.Backtrack[i] )
	  goto next_chainposrule;
      }
    }

    /* Start at 1 because [0] is implied */

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

	if ( j + igc - i + lgc == (HB_Int)buffer->in_length )
	  goto next_chainposrule;
	j++;
      }

      if ( IN_GLYPH( j ) != curr_cpr.Input[i - 1] )
	goto next_chainposrule;
    }

    /* we are starting to check for lookahead glyphs right after the
       last context glyph                                            */

    for ( i = 0; i < lgc; i++, j++ )
    {
      while ( CHECK_Property( layout, IN_ITEM( j ), flags, &property ) )
      {
	if ( error && error != HB_Err_Not_Covered )
	  return error;

	if ( j + lgc - i == (HB_Int)buffer->in_length )
	  goto next_chainposrule;
	j++;
      }

      if ( IN_GLYPH( j ) != curr_cpr.Lookahead[i] )
	goto next_chainposrule;
    }

    return Do_ContextPos( gpi, igc,
			  curr_cpr.PosCount,
			  curr_cpr.PosLookupRecord,
			  buffer,
			  nesting_level );

  next_chainposrule:
    ;
  }

  return HB_Err_Not_Covered;
}


static HB_Error  Lookup_ChainContextPos2(
		   GPOS_Instance*               gpi,
		   HB_ChainContextPosFormat2*  ccpf2,
		   HB_Buffer                   buffer,
		   HB_UShort                    flags,
		   HB_UShort                    context_length,
		   int                          nesting_level )
{
  HB_UShort              index, property;
  HB_Error               error;
  HB_UShort              i, j, k;
  HB_UShort              bgc, igc, lgc;
  HB_UShort              known_backtrack_classes,
			 known_input_classes,
			 known_lookahead_classes;

  HB_UShort*             backtrack_classes;
  HB_UShort*             input_classes;
  HB_UShort*             lookahead_classes;

  HB_UShort*             bc;
  HB_UShort*             ic;
  HB_UShort*             lc;
  HB_GPOSHeader*        gpos = gpi->gpos;

  HB_ChainPosClassSet*  cpcs;
  HB_ChainPosClassRule  cpcr;
  hb_ot_layout_t*        layout;


  layout = gpos->layout;

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

  /* Note: The coverage table in format 2 doesn't give an index into
	   anything.  It just lets us know whether or not we need to
	   do any lookup at all.                                     */

  error = _HB_OPEN_Coverage_Index( &ccpf2->Coverage, IN_CURGLYPH(), &index );
  if ( error )
    return error;

  if ( ALLOC_ARRAY( backtrack_classes, ccpf2->MaxBacktrackLength, HB_UShort ) )
    return error;
  known_backtrack_classes = 0;

  if (ccpf2->MaxInputLength < 1)
    return HB_Err_Not_Covered;

  if ( ALLOC_ARRAY( input_classes, ccpf2->MaxInputLength, HB_UShort ) )
    goto End3;
  known_input_classes = 1;

  if ( ALLOC_ARRAY( lookahead_classes, ccpf2->MaxLookaheadLength, HB_UShort ) )
    goto End2;
  known_lookahead_classes = 0;

  error = _HB_OPEN_Get_Class( &ccpf2->InputClassDef, IN_CURGLYPH(),
		     &input_classes[0], NULL );
  if ( error && error != HB_Err_Not_Covered )
    goto End1;

  cpcs = &ccpf2->ChainPosClassSet[input_classes[0]];
  if ( !cpcs )
  {
    error = ERR(HB_Err_Invalid_SubTable);
    goto End1;
  }

  for ( k = 0; k < cpcs->ChainPosClassRuleCount; k++ )
  {
    cpcr = cpcs->ChainPosClassRule[k];
    bgc  = cpcr.BacktrackGlyphCount;
    igc  = cpcr.InputGlyphCount;
    lgc  = cpcr.LookaheadGlyphCount;

    if ( context_length != 0xFFFF && context_length < igc )
      goto next_chainposclassrule;

    /* check whether context is too long; it is a first guess only */

    if ( bgc > buffer->in_pos || buffer->in_pos + igc + lgc > buffer->in_length )
      goto next_chainposclassrule;

    if ( bgc )
    {
      /* Since we don't know in advance the number of glyphs to inspect,
	 we search backwards for matches in the backtrack glyph array.
	 Note that `known_backtrack_classes' starts at index 0.         */

      bc       = cpcr.Backtrack;

      for ( i = 0, j = buffer->in_pos - 1; i < bgc; i++, j-- )
      {
	while ( CHECK_Property( layout, IN_ITEM( j ), flags, &property ) )
	{
	  if ( error && error != HB_Err_Not_Covered )
	    goto End1;

	  if ( j + 1 == bgc - i )
	    goto next_chainposclassrule;
	  j++;
	}

	if ( i >= known_backtrack_classes )
	{
	  /* Keeps us from having to do this for each rule */

	  error = _HB_OPEN_Get_Class( &ccpf2->BacktrackClassDef, IN_GLYPH( j ),
			     &backtrack_classes[i], NULL );
	  if ( error && error != HB_Err_Not_Covered )
	    goto End1;
	  known_backtrack_classes = i;
	}

	if ( bc[i] != backtrack_classes[i] )
	  goto next_chainposclassrule;
      }
    }

    ic       = cpcr.Input;

    /* Start at 1 because [0] is implied */

    for ( i = 1, j = buffer->in_pos + 1; i < igc; i++, j++ )
    {
      while ( CHECK_Property( layout, IN_ITEM( j ), flags, &property ) )
      {
	if ( error && error != HB_Err_Not_Covered )
	  goto End1;

	if ( j + igc - i + lgc == (HB_Int)buffer->in_length )
	  goto next_chainposclassrule;
	j++;
      }

      if ( i >= known_input_classes )
      {
	error = _HB_OPEN_Get_Class( &ccpf2->InputClassDef, IN_GLYPH( j ),
			   &input_classes[i], NULL );
	if ( error && error != HB_Err_Not_Covered )
	  goto End1;
	known_input_classes = i;
      }

      if ( ic[i - 1] != input_classes[i] )
	goto next_chainposclassrule;
    }

    /* we are starting to check for lookahead glyphs right after the
       last context glyph                                            */

    lc       = cpcr.Lookahead;

    for ( i = 0; i < lgc; i++, j++ )
    {
      while ( CHECK_Property( layout, IN_ITEM( j ), flags, &property ) )
      {
	if ( error && error != HB_Err_Not_Covered )
	  goto End1;

	if ( j + lgc - i == (HB_Int)buffer->in_length )
	  goto next_chainposclassrule;
	j++;
      }

      if ( i >= known_lookahead_classes )
      {
	error = _HB_OPEN_Get_Class( &ccpf2->LookaheadClassDef, IN_GLYPH( j ),
			   &lookahead_classes[i], NULL );
	if ( error && error != HB_Err_Not_Covered )
	  goto End1;
	known_lookahead_classes = i;
      }

      if ( lc[i] != lookahead_classes[i] )
	goto next_chainposclassrule;
    }

    error = Do_ContextPos( gpi, igc,
			   cpcr.PosCount,
			   cpcr.PosLookupRecord,
			   buffer,
			   nesting_level );
    goto End1;

  next_chainposclassrule:
    ;
  }

  error = HB_Err_Not_Covered;

End1:
  FREE( lookahead_classes );

End2:
  FREE( input_classes );

End3:
  FREE( backtrack_classes );
  return error;
}


static HB_Error  Lookup_ChainContextPos3(
		   GPOS_Instance*               gpi,
		   HB_ChainContextPosFormat3*  ccpf3,
		   HB_Buffer                   buffer,
		   HB_UShort                    flags,
		   HB_UShort                    context_length,
		   int                          nesting_level )
{
  HB_UShort        index, i, j, property;
  HB_UShort        bgc, igc, lgc;
  HB_Error         error;
  HB_GPOSHeader*  gpos = gpi->gpos;

  HB_Coverage*    bc;
  HB_Coverage*    ic;
  HB_Coverage*    lc;
  hb_ot_layout_t*  layout;


  layout = gpos->layout;

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

  bgc = ccpf3->BacktrackGlyphCount;
  igc = ccpf3->InputGlyphCount;
  lgc = ccpf3->LookaheadGlyphCount;

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

  /* check whether context is too long; it is a first guess only */

  if ( bgc > buffer->in_pos || buffer->in_pos + igc + lgc > buffer->in_length )
    return HB_Err_Not_Covered;

  if ( bgc )
  {
    /* Since we don't know in advance the number of glyphs to inspect,
       we search backwards for matches in the backtrack glyph array    */

    bc       = ccpf3->BacktrackCoverage;

    for ( i = 0, j = buffer->in_pos - 1; i < bgc; i++, j-- )
    {
      while ( CHECK_Property( layout, IN_ITEM( j ), flags, &property ) )
      {
	if ( error && error != HB_Err_Not_Covered )
	  return error;

	if ( j + 1 == bgc - i )
	  return HB_Err_Not_Covered;
	j--;
      }

      error = _HB_OPEN_Coverage_Index( &bc[i], IN_GLYPH( j ), &index );
      if ( error )
	return error;
    }
  }

  ic       = ccpf3->InputCoverage;

  for ( i = 0, j = buffer->in_pos; i < igc; i++, j++ )
  {
    /* We already called CHECK_Property for IN_GLYPH ( buffer->in_pos ) */
    while ( j > buffer->in_pos && CHECK_Property( layout, IN_ITEM( j ), flags, &property ) )
    {
      if ( error && error != HB_Err_Not_Covered )
	return error;

      if ( j + igc - i + lgc == (HB_Int)buffer->in_length )
	return HB_Err_Not_Covered;
      j++;
    }

    error = _HB_OPEN_Coverage_Index( &ic[i], IN_GLYPH( j ), &index );
    if ( error )
      return error;
  }

  /* we are starting to check for lookahead glyphs right after the
     last context glyph                                            */

  lc       = ccpf3->LookaheadCoverage;

  for ( i = 0; i < lgc; i++, j++ )
  {
    while ( CHECK_Property( layout, IN_ITEM( j ), flags, &property ) )
    {
      if ( error && error != HB_Err_Not_Covered )
	return error;

      if ( j + lgc - i == (HB_Int)buffer->in_length )
	return HB_Err_Not_Covered;
      j++;
    }

    error = _HB_OPEN_Coverage_Index( &lc[i], IN_GLYPH( j ), &index );
    if ( error )
      return error;
  }

  return Do_ContextPos( gpi, igc,
			ccpf3->PosCount,
			ccpf3->PosLookupRecord,
			buffer,
			nesting_level );
}


static HB_Error  Lookup_ChainContextPos(
		   GPOS_Instance*        gpi,
		   HB_GPOS_SubTable* st,
		   HB_Buffer            buffer,
		   HB_UShort             flags,
		   HB_UShort             context_length,
		   int                   nesting_level )
{
  HB_ChainContextPos*  ccp = &st->chain;

  switch ( ccp->PosFormat )
  {
  case 1:
    return Lookup_ChainContextPos1( gpi, &ccp->ccpf.ccpf1, buffer,
				    flags, context_length,
				    nesting_level );

  case 2:
    return Lookup_ChainContextPos2( gpi, &ccp->ccpf.ccpf2, buffer,
				    flags, context_length,
				    nesting_level );

  case 3:
    return Lookup_ChainContextPos3( gpi, &ccp->ccpf.ccpf3, buffer,
				    flags, context_length,
				    nesting_level );

  default:
    return ERR(HB_Err_Invalid_SubTable_Format);
  }

  return HB_Err_Ok;               /* never reached */
}



/***********
 * GPOS API
 ***********/



HB_Error  HB_GPOS_Select_Script( HB_GPOSHeader*  gpos,
				 HB_UInt         script_tag,
				 HB_UShort*       script_index )
{
  HB_UShort          n;

  HB_ScriptList*    sl;
  HB_ScriptRecord*  sr;


  if ( !gpos || !script_index )
    return ERR(HB_Err_Invalid_Argument);

  sl = &gpos->ScriptList;
  sr = sl->ScriptRecord;

  for ( n = 0; n < sl->ScriptCount; n++ )
    if ( script_tag == sr[n].ScriptTag )
    {
      *script_index = n;

      return HB_Err_Ok;
    }

  return HB_Err_Not_Covered;
}



HB_Error  HB_GPOS_Select_Language( HB_GPOSHeader*  gpos,
				   HB_UInt         language_tag,
				   HB_UShort        script_index,
				   HB_UShort*       language_index,
				   HB_UShort*       req_feature_index )
{
  HB_UShort           n;

  HB_ScriptList*     sl;
  HB_ScriptRecord*   sr;
  HB_ScriptTable*         s;
  HB_LangSysRecord*  lsr;


  if ( !gpos || !language_index || !req_feature_index )
    return ERR(HB_Err_Invalid_Argument);

  sl = &gpos->ScriptList;
  sr = sl->ScriptRecord;

  if ( script_index >= sl->ScriptCount )
    return ERR(HB_Err_Invalid_Argument);

  s   = &sr[script_index].Script;
  lsr = s->LangSysRecord;

  for ( n = 0; n < s->LangSysCount; n++ )
    if ( language_tag == lsr[n].LangSysTag )
    {
      *language_index = n;
      *req_feature_index = lsr[n].LangSys.ReqFeatureIndex;

      return HB_Err_Ok;
    }

  return HB_Err_Not_Covered;
}


/* selecting 0xFFFF for language_index asks for the values of the
   default language (DefaultLangSys)                              */


HB_Error  HB_GPOS_Select_Feature( HB_GPOSHeader*  gpos,
				  HB_UInt         feature_tag,
				  HB_UShort        script_index,
				  HB_UShort        language_index,
				  HB_UShort*       feature_index )
{
  HB_UShort           n;

  HB_ScriptList*     sl;
  HB_ScriptRecord*   sr;
  HB_ScriptTable*         s;
  HB_LangSysRecord*  lsr;
  HB_LangSys*        ls;
  HB_UShort*          fi;

  HB_FeatureList*    fl;
  HB_FeatureRecord*  fr;


  if ( !gpos || !feature_index )
    return ERR(HB_Err_Invalid_Argument);

  sl = &gpos->ScriptList;
  sr = sl->ScriptRecord;

  fl = &gpos->FeatureList;
  fr = fl->FeatureRecord;

  if ( script_index >= sl->ScriptCount )
    return ERR(HB_Err_Invalid_Argument);

  s   = &sr[script_index].Script;
  lsr = s->LangSysRecord;

  if ( language_index == 0xFFFF )
    ls = &s->DefaultLangSys;
  else
  {
    if ( language_index >= s->LangSysCount )
      return ERR(HB_Err_Invalid_Argument);

    ls = &lsr[language_index].LangSys;
  }

  fi = ls->FeatureIndex;

  for ( n = 0; n < ls->FeatureCount; n++ )
  {
    if ( fi[n] >= fl->FeatureCount )
      return ERR(HB_Err_Invalid_SubTable_Format);

    if ( feature_tag == fr[fi[n]].FeatureTag )
    {
      *feature_index = fi[n];

      return HB_Err_Ok;
    }
  }

  return HB_Err_Not_Covered;
}


/* The next three functions return a null-terminated list */


HB_Error  HB_GPOS_Query_Scripts( HB_GPOSHeader*  gpos,
				 HB_UInt**       script_tag_list )
{
  HB_Error           error;
  HB_UShort          n;
  HB_UInt*          stl;

  HB_ScriptList*    sl;
  HB_ScriptRecord*  sr;


  if ( !gpos || !script_tag_list )
    return ERR(HB_Err_Invalid_Argument);

  sl = &gpos->ScriptList;
  sr = sl->ScriptRecord;

  if ( ALLOC_ARRAY( stl, sl->ScriptCount + 1, HB_UInt ) )
    return error;

  for ( n = 0; n < sl->ScriptCount; n++ )
    stl[n] = sr[n].ScriptTag;
  stl[n] = 0;

  *script_tag_list = stl;

  return HB_Err_Ok;
}



HB_Error  HB_GPOS_Query_Languages( HB_GPOSHeader*  gpos,
				   HB_UShort        script_index,
				   HB_UInt**       language_tag_list )
{
  HB_Error            error;
  HB_UShort           n;
  HB_UInt*           ltl;

  HB_ScriptList*     sl;
  HB_ScriptRecord*   sr;
  HB_ScriptTable*         s;
  HB_LangSysRecord*  lsr;


  if ( !gpos || !language_tag_list )
    return ERR(HB_Err_Invalid_Argument);

  sl = &gpos->ScriptList;
  sr = sl->ScriptRecord;

  if ( script_index >= sl->ScriptCount )
    return ERR(HB_Err_Invalid_Argument);

  s   = &sr[script_index].Script;
  lsr = s->LangSysRecord;

  if ( ALLOC_ARRAY( ltl, s->LangSysCount + 1, HB_UInt ) )
    return error;

  for ( n = 0; n < s->LangSysCount; n++ )
    ltl[n] = lsr[n].LangSysTag;
  ltl[n] = 0;

  *language_tag_list = ltl;

  return HB_Err_Ok;
}


/* selecting 0xFFFF for language_index asks for the values of the
   default language (DefaultLangSys)                              */


HB_Error  HB_GPOS_Query_Features( HB_GPOSHeader*  gpos,
				  HB_UShort        script_index,
				  HB_UShort        language_index,
				  HB_UInt**       feature_tag_list )
{
  HB_UShort           n;
  HB_Error            error;
  HB_UInt*           ftl;

  HB_ScriptList*     sl;
  HB_ScriptRecord*   sr;
  HB_ScriptTable*         s;
  HB_LangSysRecord*  lsr;
  HB_LangSys*        ls;
  HB_UShort*          fi;

  HB_FeatureList*    fl;
  HB_FeatureRecord*  fr;


  if ( !gpos || !feature_tag_list )
    return ERR(HB_Err_Invalid_Argument);

  sl = &gpos->ScriptList;
  sr = sl->ScriptRecord;

  fl = &gpos->FeatureList;
  fr = fl->FeatureRecord;

  if ( script_index >= sl->ScriptCount )
    return ERR(HB_Err_Invalid_Argument);

  s   = &sr[script_index].Script;
  lsr = s->LangSysRecord;

  if ( language_index == 0xFFFF )
    ls = &s->DefaultLangSys;
  else
  {
    if ( language_index >= s->LangSysCount )
      return ERR(HB_Err_Invalid_Argument);

    ls = &lsr[language_index].LangSys;
  }

  fi = ls->FeatureIndex;

  if ( ALLOC_ARRAY( ftl, ls->FeatureCount + 1, HB_UInt ) )
    return error;

  for ( n = 0; n < ls->FeatureCount; n++ )
  {
    if ( fi[n] >= fl->FeatureCount )
    {
      FREE( ftl );
      return ERR(HB_Err_Invalid_SubTable_Format);
    }
    ftl[n] = fr[fi[n]].FeatureTag;
  }
  ftl[n] = 0;

  *feature_tag_list = ftl;

  return HB_Err_Ok;
}


/* Do an individual subtable lookup.  Returns HB_Err_Ok if positioning
   has been done, or HB_Err_Not_Covered if not.                        */
static HB_Error  GPOS_Do_Glyph_Lookup( GPOS_Instance*    gpi,
				       HB_UShort         lookup_index,
				       HB_Buffer        buffer,
				       HB_UShort         context_length,
				       int               nesting_level )
{
  HB_Error             error = HB_Err_Not_Covered;
  HB_UShort            i, flags, lookup_count;
  HB_GPOSHeader*       gpos = gpi->gpos;
  HB_Lookup*           lo;
  int		       lookup_type;


  nesting_level++;

  if ( nesting_level > HB_MAX_NESTING_LEVEL )
    return ERR(HB_Err_Not_Covered); /* ERR() call intended */

  lookup_count = gpos->LookupList.LookupCount;
  if (lookup_index >= lookup_count)
    return error;

  lo    = &gpos->LookupList.Lookup[lookup_index];
  flags = lo->LookupFlag;
  lookup_type = lo->LookupType;

  for ( i = 0; i < lo->SubTableCount; i++ )
  {
    HB_GPOS_SubTable *st = &lo->SubTable[i].st.gpos;

    switch (lookup_type) {
      case HB_GPOS_LOOKUP_SINGLE:
        error = Lookup_SinglePos	( gpi, st, buffer, flags, context_length, nesting_level ); break;
      case HB_GPOS_LOOKUP_PAIR:
	error = Lookup_PairPos		( gpi, st, buffer, flags, context_length, nesting_level ); break;
      case HB_GPOS_LOOKUP_CURSIVE:
	error = Lookup_CursivePos	( gpi, st, buffer, flags, context_length, nesting_level ); break;
      case HB_GPOS_LOOKUP_MARKBASE:
	error = Lookup_MarkBasePos	( gpi, st, buffer, flags, context_length, nesting_level ); break;
      case HB_GPOS_LOOKUP_MARKLIG:
	error = Lookup_MarkLigPos	( gpi, st, buffer, flags, context_length, nesting_level ); break;
      case HB_GPOS_LOOKUP_MARKMARK:
	error = Lookup_MarkMarkPos	( gpi, st, buffer, flags, context_length, nesting_level ); break;
      case HB_GPOS_LOOKUP_CONTEXT:
	error = Lookup_ContextPos	( gpi, st, buffer, flags, context_length, nesting_level ); break;
      case HB_GPOS_LOOKUP_CHAIN:
	error = Lookup_ChainContextPos	( gpi, st, buffer, flags, context_length, nesting_level ); break;
    /*case HB_GPOS_LOOKUP_EXTENSION:
	error = Lookup_ExtensionPos	( gpi, st, buffer, flags, context_length, nesting_level ); break;*/
      default:
	error = HB_Err_Not_Covered;
    }

    /* Check whether we have a successful positioning or an error other
       than HB_Err_Not_Covered                                         */
    if ( error != HB_Err_Not_Covered )
      return error;
  }

  return HB_Err_Not_Covered;
}


HB_INTERNAL HB_Error
_HB_GPOS_Load_SubTable( HB_GPOS_SubTable* st,
			HB_Stream         stream,
			HB_UShort         lookup_type )
{
  switch ( lookup_type ) {
    case HB_GPOS_LOOKUP_SINGLE:		return Load_SinglePos		( st, stream );
    case HB_GPOS_LOOKUP_PAIR:		return Load_PairPos		( st, stream );
    case HB_GPOS_LOOKUP_CURSIVE:	return Load_CursivePos		( st, stream );
    case HB_GPOS_LOOKUP_MARKBASE:	return Load_MarkBasePos		( st, stream );
    case HB_GPOS_LOOKUP_MARKLIG:	return Load_MarkLigPos		( st, stream );
    case HB_GPOS_LOOKUP_MARKMARK:	return Load_MarkMarkPos		( st, stream );
    case HB_GPOS_LOOKUP_CONTEXT:	return Load_ContextPos		( st, stream );
    case HB_GPOS_LOOKUP_CHAIN:		return Load_ChainContextPos	( st, stream );
  /*case HB_GPOS_LOOKUP_EXTENSION:	return Load_ExtensionPos	( st, stream );*/
    default:				return ERR(HB_Err_Invalid_SubTable_Format);
  }
}


HB_INTERNAL void
_HB_GPOS_Free_SubTable( HB_GPOS_SubTable* st,
			HB_UShort         lookup_type )
{
  switch ( lookup_type ) {
    case HB_GPOS_LOOKUP_SINGLE:		Free_SinglePos		( st ); return;
    case HB_GPOS_LOOKUP_PAIR:		Free_PairPos		( st ); return;
    case HB_GPOS_LOOKUP_CURSIVE:	Free_CursivePos		( st ); return;
    case HB_GPOS_LOOKUP_MARKBASE:	Free_MarkBasePos	( st ); return;
    case HB_GPOS_LOOKUP_MARKLIG:	Free_MarkLigPos		( st ); return;
    case HB_GPOS_LOOKUP_MARKMARK:	Free_MarkMarkPos	( st ); return;
    case HB_GPOS_LOOKUP_CONTEXT:	Free_ContextPos		( st ); return;
    case HB_GPOS_LOOKUP_CHAIN:		Free_ChainContextPos	( st ); return;
  /*case HB_GPOS_LOOKUP_EXTENSION:	Free_ExtensionPos	( st ); return;*/
    default:									return;
  }
}


/* apply one lookup to the input string object */

static HB_Error  GPOS_Do_String_Lookup( GPOS_Instance*    gpi,
				   HB_UShort         lookup_index,
				   HB_Buffer        buffer )
{
  HB_Error         error, retError = HB_Err_Not_Covered;
  HB_GPOSHeader*  gpos = gpi->gpos;

  HB_UInt*  properties = gpos->LookupList.Properties;

  const int       nesting_level = 0;
  /* 0xFFFF indicates that we don't have a context length yet */
  const HB_UShort context_length = 0xFFFF;


  gpi->last  = 0xFFFF;     /* no last valid glyph for cursive pos. */

  buffer->in_pos = 0;
  while ( buffer->in_pos < buffer->in_length )
  {
    if ( ~IN_PROPERTIES( buffer->in_pos ) & properties[lookup_index] )
    {
      /* Note that the connection between mark and base glyphs hold
	 exactly one (string) lookup.  For example, it would be possible
	 that in the first lookup, mark glyph X is attached to base
	 glyph A, and in the next lookup it is attached to base glyph B.
	 It is up to the font designer to provide meaningful lookups and
	 lookup order.                                                   */

      error = GPOS_Do_Glyph_Lookup( gpi, lookup_index, buffer, context_length, nesting_level );
      if ( error && error != HB_Err_Not_Covered )
	return error;
    }
    else
    {
      /* Contrary to properties defined in GDEF, user-defined properties
	 will always stop a possible cursive positioning.                */
      gpi->last = 0xFFFF;

      error = HB_Err_Not_Covered;
    }

    if ( error == HB_Err_Not_Covered )
      (buffer->in_pos)++;
    else
      retError = error;
  }

  return retError;
}


static HB_Error  Position_CursiveChain ( HB_Buffer     buffer )
{
  HB_UInt   i, j;
  HB_Position positions = buffer->positions;

  /* First handle all left-to-right connections */
  for (j = 0; j < buffer->in_length; j++)
  {
    if (positions[j].cursive_chain > 0)
      positions[j].y_pos += positions[j - positions[j].cursive_chain].y_pos;
  }

  /* Then handle all right-to-left connections */
  for (i = buffer->in_length; i > 0; i--)
  {
    j = i - 1;

    if (positions[j].cursive_chain < 0)
      positions[j].y_pos += positions[j - positions[j].cursive_chain].y_pos;
  }

  return HB_Err_Ok;
}


HB_Error  HB_GPOS_Add_Feature( HB_GPOSHeader*  gpos,
			       HB_UShort        feature_index,
			       HB_UInt          property )
{
  HB_UShort    i;

  HB_Feature  feature;
  HB_UInt*     properties;
  HB_UShort*   index;
  HB_UShort    lookup_count;

  /* Each feature can only be added once */

  if ( !gpos ||
       feature_index >= gpos->FeatureList.FeatureCount ||
       gpos->FeatureList.ApplyCount == gpos->FeatureList.FeatureCount )
    return ERR(HB_Err_Invalid_Argument);

  gpos->FeatureList.ApplyOrder[gpos->FeatureList.ApplyCount++] = feature_index;

  properties = gpos->LookupList.Properties;

  feature = gpos->FeatureList.FeatureRecord[feature_index].Feature;
  index   = feature.LookupListIndex;
  lookup_count = gpos->LookupList.LookupCount;

  for ( i = 0; i < feature.LookupListCount; i++ )
  {
    HB_UShort lookup_index = index[i];
    if (lookup_index < lookup_count)
      properties[lookup_index] |= property;
  }

  return HB_Err_Ok;
}



HB_Error  HB_GPOS_Clear_Features( HB_GPOSHeader*  gpos )
{
  HB_UShort i;

  HB_UInt*  properties;


  if ( !gpos )
    return ERR(HB_Err_Invalid_Argument);

  gpos->FeatureList.ApplyCount = 0;

  properties = gpos->LookupList.Properties;

  for ( i = 0; i < gpos->LookupList.LookupCount; i++ )
    properties[i] = 0;

  return HB_Err_Ok;
}



HB_Error  HB_GPOS_Register_Glyph_Function( HB_GPOSHeader*    gpos,
					   HB_GlyphFunction  gfunc )
{
  if ( !gpos )
    return ERR(HB_Err_Invalid_Argument);

  gpos->gfunc = gfunc;

  return HB_Err_Ok;
}



HB_Error  HB_GPOS_Register_MM_Function( HB_GPOSHeader*  gpos,
					HB_MMFunction   mmfunc,
					void*            data )
{
  if ( !gpos )
    return ERR(HB_Err_Invalid_Argument);

  gpos->mmfunc = mmfunc;
  gpos->data   = data;

  return HB_Err_Ok;
}

/* If `dvi' is TRUE, glyph contour points for anchor points and device
   tables are ignored -- you will get device independent values.         */


HB_Error  HB_GPOS_Apply_String( HB_Font           font,
				HB_GPOSHeader*    gpos,
				HB_UShort         load_flags,
				HB_Buffer         buffer,
				HB_Bool           dvi,
				HB_Bool           r2l )
{
  HB_Error       error, retError = HB_Err_Not_Covered;
  GPOS_Instance  gpi;
  int            i, j, lookup_count, num_features;

  if ( !font || !gpos || !buffer )
    return ERR(HB_Err_Invalid_Argument);

  if ( buffer->in_length == 0 )
    return HB_Err_Not_Covered;

  gpi.font       = font;
  gpi.gpos       = gpos;
  gpi.load_flags = load_flags;
  gpi.r2l        = r2l;
  gpi.dvi        = dvi;

  lookup_count = gpos->LookupList.LookupCount;
  num_features = gpos->FeatureList.ApplyCount;

  if ( num_features )
    {
      error = _hb_buffer_clear_positions( buffer );
      if ( error )
	return error;
    }

  for ( i = 0; i < num_features; i++ )
  {
    HB_UShort  feature_index = gpos->FeatureList.ApplyOrder[i];
    HB_Feature feature = gpos->FeatureList.FeatureRecord[feature_index].Feature;

    for ( j = 0; j < feature.LookupListCount; j++ )
    {
      HB_UShort lookup_index = feature.LookupListIndex[j];

      /* Skip nonexistant lookups */
      if (lookup_index >= lookup_count)
       continue;

      error = GPOS_Do_String_Lookup( &gpi, lookup_index, buffer );
      if ( error )
      {
	if ( error != HB_Err_Not_Covered )
	  return error;
      }
      else
	retError = error;
    }
  }

  if ( num_features )
    {
      error = Position_CursiveChain ( buffer );
      if ( error )
	return error;
    }

  return retError;
}

/* END */