src/hb-ot-layout-gdef-private.h

/*
 * Copyright (C) 2007,2008,2009  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
 */

#ifndef HB_OT_LAYOUT_GDEF_PRIVATE_H
#define HB_OT_LAYOUT_GDEF_PRIVATE_H

#include "hb-ot-layout-common-private.h"


#define DEFINE_INDIRECT_GLYPH_ARRAY_LOOKUP(Type, array, name) \
  inline const Type& name (hb_codepoint_t glyph) { \
    return this+array[(this+coverage)(glyph)]; \
  }


struct GlyphClassDef : ClassDef {
  static const unsigned int BaseGlyph		= 0x0001u;
  static const unsigned int LigatureGlyph	= 0x0002u;
  static const unsigned int MarkGlyph		= 0x0003u;
  static const unsigned int ComponentGlyph	= 0x0004u;
};

/*
 * Attachment List Table
 */

struct AttachPoint {
  ArrayOf<USHORT>
		pointIndex;		/* Array of contour point indices--in
					 * increasing numerical order */
};
ASSERT_SIZE (AttachPoint, 2);

struct AttachList {

  /* const AttachPoint& get_attach_points (hb_codepoint_t glyph); */
  DEFINE_INDIRECT_GLYPH_ARRAY_LOOKUP (AttachPoint, attachPoint, get_attach_points);

 private:
  OffsetTo<Coverage>
		coverage;		/* Offset to Coverage table -- from
					 * beginning of AttachList table */
  OffsetArrayOf<AttachPoint>
		attachPoint;		/* Array of AttachPoint tables
					 * in Coverage Index order */
};
ASSERT_SIZE (AttachList, 4);

/*
 * Ligature Caret Table
 */

struct CaretValueFormat1 {

  friend struct CaretValue;

  private:
  inline int get_caret_value (int ppem) const {
    return /* TODO garbage */ coordinate / ppem;
  }

  private:
  USHORT	caretValueFormat;	/* Format identifier--format = 1 */
  SHORT		coordinate;		/* X or Y value, in design units */
};
ASSERT_SIZE (CaretValueFormat1, 4);

struct CaretValueFormat2 {

  friend struct CaretValue;

  private:
  inline int get_caret_value (int ppem) const {
    return /* TODO garbage */ 0 / ppem;
  }

  private:
  USHORT	caretValueFormat;	/* Format identifier--format = 2 */
  USHORT	caretValuePoint;	/* Contour point index on glyph */
};
ASSERT_SIZE (CaretValueFormat2, 4);

struct CaretValueFormat3 {

  friend struct CaretValue;

  private:
  inline const Device& get_device (void) const {
    if (HB_UNLIKELY (!deviceTable)) return Null(Device);
    return *(const Device*)((const char*)this + deviceTable);
  }

  inline int get_caret_value (int ppem) const {
    return /* TODO garbage */ (coordinate + get_device().get_delta (ppem)) / ppem;
  }

  private:
  USHORT	caretValueFormat;	/* Format identifier--format = 3 */
  SHORT		coordinate;		/* X or Y value, in design units */
  Offset	deviceTable;		/* Offset to Device table for X or Y
					 * value--from beginning of CaretValue
					 * table */
};
ASSERT_SIZE (CaretValueFormat3, 6);

struct CaretValue {
  /* XXX  we need access to a load-contour-point vfunc here */
  int get_caret_value (int ppem) const {
    switch (u.format) {
    case 1: return u.format1->get_caret_value(ppem);
    case 2: return u.format2->get_caret_value(ppem);
    case 3: return u.format3->get_caret_value(ppem);
    default:return 0;
    }
  }

  private:
  union {
  USHORT		format;		/* Format identifier */
  CaretValueFormat1	format1[];
  CaretValueFormat2	format2[];
  CaretValueFormat3	format3[];
  } u;
};
ASSERT_SIZE (CaretValue, 2);

struct LigGlyph {

  friend struct LigCaretList;

  OffsetArrayOf<CaretValue>
		caret;			/* Array of CaretValue tables
					 * in increasing coordinate order */
};
ASSERT_SIZE (LigGlyph, 2);

struct LigCaretList {

  friend struct GDEF;

  private:
  /* const LigGlyph& get_lig_glyph (hb_codepoint_t glyph); */
  DEFINE_INDIRECT_GLYPH_ARRAY_LOOKUP (LigGlyph, ligGlyph, get_lig_glyph);

  private:
  OffsetTo<Coverage>
		coverage;		/* Offset to Coverage table--from
					 * beginning of LigCaretList table */
  OffsetArrayOf<LigGlyph>
		ligGlyph;		/* Array of LigGlyph tables
					 * in Coverage Index order */
};
ASSERT_SIZE (LigCaretList, 4);

/*
 * GDEF
 */

struct GDEF {
  static const hb_tag_t Tag		= HB_TAG ('G','D','E','F');

  static const hb_ot_layout_class_t UnclassifiedGlyph	= 0;
  static const hb_ot_layout_class_t BaseGlyph		= 1;
  static const hb_ot_layout_class_t LigatureGlyph	= 2;
  static const hb_ot_layout_class_t MarkGlyph		= 3;
  static const hb_ot_layout_class_t ComponentGlyph	= 4;

  STATIC_DEFINE_GET_FOR_DATA (GDEF);
  /* XXX check version here? */

  inline bool has_glyph_classes () const { return glyphClassDef != 0; }
  inline hb_ot_layout_class_t get_glyph_class (hb_codepoint_t glyph) const {
    return glyphClassDef(this).get_class (glyph);
  }

  inline bool has_mark_attachment_types () const { return markAttachClassDef != 0; }
  inline hb_ot_layout_class_t get_mark_attachment_type (hb_codepoint_t glyph) const {
    return markAttachClassDef(this).get_class (glyph);
  }

  /* TODO get_attach and get_lig_caret */
  inline bool has_attach_list () const { return attachList != 0; }
  inline bool has_lig_caret_list () const { return ligCaretList != 0; }

  private:
  Fixed		version;		/* Version of the GDEF table--initially
					 * 0x00010000 */
  OffsetTo<ClassDef>
		glyphClassDef;		/* Offset to class definition table
					 * for glyph type--from beginning of
					 * GDEF header (may be Null) */
  OffsetTo<AttachList>
		attachList;		/* Offset to list of glyphs with
					 * attachment points--from beginning
					 * of GDEF header (may be Null) */
  OffsetTo<LigCaretList>
		ligCaretList;		/* Offset to list of positioning points
					 * for ligature carets--from beginning
					 * of GDEF header (may be Null) */
  OffsetTo<ClassDef>
		markAttachClassDef;	/* Offset to class definition table for
					 * mark attachment type--from beginning
					 * of GDEF header (may be Null) */
};
ASSERT_SIZE (GDEF, 12);


#endif /* HB_OT_LAYOUT_GDEF_PRIVATE_H */