text:
/*
 * Copyright (C) 2011  Google, Inc.
 *
 *  This is part of HarfBuzz, a text shaping 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.
 *
 * Google Author(s): Behdad Esfahbod
 */

#ifndef HB_GOBJECT_H
#define HB_GOBJECT_H
#define HB_GOBJECT_H_IN

#include "hb.h"

#include "hb-gobject-enums.h"
#include "hb-gobject-structs.h"

HB_BEGIN_DECLS
HB_END_DECLS

#undef HB_GOBJECT_H_IN
#endif /* HB_GOBJECT_H */


text:
/*
 * Copyright © 2007,2008,2009,2010  Red Hat, Inc.
 * Copyright © 2010,2012,2013  Google, Inc.
 *
 *  This is part of HarfBuzz, a text shaping 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
 * Google Author(s): Behdad Esfahbod
 */

#ifndef HB_OT_LAYOUT_GSUB_TABLE_HH
#define HB_OT_LAYOUT_GSUB_TABLE_HH

#include "hb-ot-layout-gsubgpos.hh"

namespace OT {

typedef hb_pair_t<hb_codepoint_t, hb_codepoint_t> hb_codepoint_pair_t;

template<typename Iterator>
static void SingleSubst_serialize (hb_serialize_context_t *c,
				   Iterator it);

struct SingleSubstFormat1
{
  bool intersects (const hb_set_t *glyphs) const
  { return (this+coverage).intersects (glyphs); }

  void closure (hb_closure_context_t *c) const
  {
    unsigned d = deltaGlyphID;
    + hb_iter (this+coverage)
    | hb_filter (*c->glyphs)
    | hb_map ([d] (hb_codepoint_t g) { return (g + d) & 0xFFFFu; })
    | hb_sink (c->output)
    ;
  }

  void closure_lookups (hb_closure_lookups_context_t *c) const {}

  void collect_glyphs (hb_collect_glyphs_context_t *c) const
  {
    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
    unsigned d = deltaGlyphID;
    + hb_iter (this+coverage)
    | hb_map ([d] (hb_codepoint_t g) { return (g + d) & 0xFFFFu; })
    | hb_sink (c->output)
    ;
  }

  const Coverage &get_coverage () const { return this+coverage; }

  bool would_apply (hb_would_apply_context_t *c) const
  { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);
    hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
    unsigned int index = (this+coverage).get_coverage (glyph_id);
    if (likely (index == NOT_COVERED)) return_trace (false);

    /* According to the Adobe Annotated OpenType Suite, result is always
     * limited to 16bit. */
    glyph_id = (glyph_id + deltaGlyphID) & 0xFFFFu;
    c->replace_glyph (glyph_id);

    return_trace (true);
  }

  template<typename Iterator,
	   hb_requires (hb_is_sorted_source_of (Iterator, hb_codepoint_t))>
  bool serialize (hb_serialize_context_t *c,
		  Iterator glyphs,
		  unsigned delta)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!c->extend_min (*this))) return_trace (false);
    if (unlikely (!coverage.serialize (c, this).serialize (c, glyphs))) return_trace (false);
    c->check_assign (deltaGlyphID, delta);
    return_trace (true);
  }

  bool subset (hb_subset_context_t *c) const
  {
    TRACE_SUBSET (this);
    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
    const hb_map_t &glyph_map = *c->plan->glyph_map;

    hb_codepoint_t delta = deltaGlyphID;

    auto it =
    + hb_iter (this+coverage)
    | hb_filter (glyphset)
    | hb_map_retains_sorting ([&] (hb_codepoint_t g) {
				return hb_codepoint_pair_t (g,
							    (g + delta) & 0xFFFF); })
    | hb_filter (glyphset, hb_second)
    | hb_map_retains_sorting ([&] (hb_codepoint_pair_t p) -> hb_codepoint_pair_t
			      { return hb_pair (glyph_map[p.first], glyph_map[p.second]); })
    ;

    bool ret = bool (it);
    SingleSubst_serialize (c->serializer, it);
    return_trace (ret);
  }

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (coverage.sanitize (c, this) && deltaGlyphID.sanitize (c));
  }

  protected:
  HBUINT16	format;			/* Format identifier--format = 1 */
  OffsetTo<Coverage>
		coverage;		/* Offset to Coverage table--from
					 * beginning of Substitution table */
  HBUINT16	deltaGlyphID;		/* Add to original GlyphID to get
					 * substitute GlyphID, modulo 0x10000 */
  public:
  DEFINE_SIZE_STATIC (6);
};

struct SingleSubstFormat2
{
  bool intersects (const hb_set_t *glyphs) const
  { return (this+coverage).intersects (glyphs); }

  void closure (hb_closure_context_t *c) const
  {
    + hb_zip (this+coverage, substitute)
    | hb_filter (*c->glyphs, hb_first)
    | hb_map (hb_second)
    | hb_sink (c->output)
    ;
  }

  void closure_lookups (hb_closure_lookups_context_t *c) const {}

  void collect_glyphs (hb_collect_glyphs_context_t *c) const
  {
    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
    + hb_zip (this+coverage, substitute)
    | hb_map (hb_second)
    | hb_sink (c->output)
    ;
  }

  const Coverage &get_coverage () const { return this+coverage; }

  bool would_apply (hb_would_apply_context_t *c) const
  { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);
    unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);
    if (likely (index == NOT_COVERED)) return_trace (false);

    if (unlikely (index >= substitute.len)) return_trace (false);

    c->replace_glyph (substitute[index]);

    return_trace (true);
  }

  template<typename Iterator,
	   hb_requires (hb_is_sorted_source_of (Iterator,
						hb_codepoint_pair_t))>
  bool serialize (hb_serialize_context_t *c,
		  Iterator it)
  {
    TRACE_SERIALIZE (this);
    auto substitutes =
      + it
      | hb_map (hb_second)
      ;
    auto glyphs =
      + it
      | hb_map_retains_sorting (hb_first)
      ;
    if (unlikely (!c->extend_min (*this))) return_trace (false);
    if (unlikely (!substitute.serialize (c, substitutes))) return_trace (false);
    if (unlikely (!coverage.serialize (c, this).serialize (c, glyphs))) return_trace (false);
    return_trace (true);
  }

  bool subset (hb_subset_context_t *c) const
  {
    TRACE_SUBSET (this);
    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
    const hb_map_t &glyph_map = *c->plan->glyph_map;

    auto it =
    + hb_zip (this+coverage, substitute)
    | hb_filter (glyphset, hb_first)
    | hb_filter (glyphset, hb_second)
    | hb_map_retains_sorting ([&] (hb_pair_t<hb_codepoint_t, const HBGlyphID &> p) -> hb_codepoint_pair_t
			      { return hb_pair (glyph_map[p.first], glyph_map[p.second]); })
    ;

    bool ret = bool (it);
    SingleSubst_serialize (c->serializer, it);
    return_trace (ret);
  }

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (coverage.sanitize (c, this) && substitute.sanitize (c));
  }

  protected:
  HBUINT16	format;			/* Format identifier--format = 2 */
  OffsetTo<Coverage>
		coverage;		/* Offset to Coverage table--from
					 * beginning of Substitution table */
  ArrayOf<HBGlyphID>
		substitute;		/* Array of substitute
					 * GlyphIDs--ordered by Coverage Index */
  public:
  DEFINE_SIZE_ARRAY (6, substitute);
};

struct SingleSubst
{

  template<typename Iterator,
	   hb_requires (hb_is_sorted_source_of (Iterator,
						const hb_codepoint_pair_t))>
  bool serialize (hb_serialize_context_t *c,
		  Iterator glyphs)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!c->extend_min (u.format))) return_trace (false);
    unsigned format = 2;
    unsigned delta = 0;
    if (glyphs)
    {
      format = 1;
      auto get_delta = [=] (hb_codepoint_pair_t _)
		       { return (unsigned) (_.second - _.first) & 0xFFFF; };
      delta = get_delta (*glyphs);
      if (!hb_all (++(+glyphs), delta, get_delta)) format = 2;
    }
    u.format = format;
    switch (u.format) {
    case 1: return_trace (u.format1.serialize (c,
					       + glyphs
					       | hb_map_retains_sorting (hb_first),
					       delta));
    case 2: return_trace (u.format2.serialize (c, glyphs));
    default:return_trace (false);
    }
  }

  template <typename context_t, typename ...Ts>
  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
  {
    TRACE_DISPATCH (this, u.format);
    if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
    switch (u.format) {
    case 1: return_trace (c->dispatch (u.format1, hb_forward<Ts> (ds)...));
    case 2: return_trace (c->dispatch (u.format2, hb_forward<Ts> (ds)...));
    default:return_trace (c->default_return_value ());
    }
  }

  protected:
  union {
  HBUINT16		format;		/* Format identifier */
  SingleSubstFormat1	format1;
  SingleSubstFormat2	format2;
  } u;
};

template<typename Iterator>
static void
SingleSubst_serialize (hb_serialize_context_t *c,
		       Iterator it)
{ c->start_embed<SingleSubst> ()->serialize (c, it); }

struct Sequence
{
  bool intersects (const hb_set_t *glyphs) const
  { return hb_all (substitute, glyphs); }

  void closure (hb_closure_context_t *c) const
  { c->output->add_array (substitute.arrayZ, substitute.len); }

  void collect_glyphs (hb_collect_glyphs_context_t *c) const
  { c->output->add_array (substitute.arrayZ, substitute.len); }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);
    unsigned int count = substitute.len;

    /* Special-case to make it in-place and not consider this
     * as a "multiplied" substitution. */
    if (unlikely (count == 1))
    {
      c->replace_glyph (substitute.arrayZ[0]);
      return_trace (true);
    }
    /* Spec disallows this, but Uniscribe allows it.
     * https://github.com/harfbuzz/harfbuzz/issues/253 */
    else if (unlikely (count == 0))
    {
      c->buffer->delete_glyph ();
      return_trace (true);
    }

    unsigned int klass = _hb_glyph_info_is_ligature (&c->buffer->cur()) ?
			 HB_OT_LAYOUT_GLYPH_PROPS_BASE_GLYPH : 0;

    for (unsigned int i = 0; i < count; i++) {
      _hb_glyph_info_set_lig_props_for_component (&c->buffer->cur(), i);
      c->output_glyph_for_component (substitute.arrayZ[i], klass);
    }
    c->buffer->skip_glyph ();

    return_trace (true);
  }

  template <typename Iterator,
	    hb_requires (hb_is_source_of (Iterator, hb_codepoint_t))>
  bool serialize (hb_serialize_context_t *c,
		  Iterator subst)
  {
    TRACE_SERIALIZE (this);
    return_trace (substitute.serialize (c, subst));
  }

  bool subset (hb_subset_context_t *c) const
  {
    TRACE_SUBSET (this);
    const hb_set_t &glyphset = *c->plan->glyphset ();
    const hb_map_t &glyph_map = *c->plan->glyph_map;

    if (!intersects (&glyphset)) return_trace (false);

    auto it =
    + hb_iter (substitute)
    | hb_map (glyph_map)
    ;

    auto *out = c->serializer->start_embed (*this);
    return_trace (out->serialize (c->serializer, it));
  }

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (substitute.sanitize (c));
  }

  protected:
  ArrayOf<HBGlyphID>
		substitute;		/* String of GlyphIDs to substitute */
  public:
  DEFINE_SIZE_ARRAY (2, substitute);
};

struct MultipleSubstFormat1
{
  bool intersects (const hb_set_t *glyphs) const
  { return (this+coverage).intersects (glyphs); }

  void closure (hb_closure_context_t *c) const
  {
    + hb_zip (this+coverage, sequence)
    | hb_filter (*c->glyphs, hb_first)
    | hb_map (hb_second)
    | hb_map (hb_add (this))
    | hb_apply ([c] (const Sequence &_) { _.closure (c); })
    ;
  }

  void closure_lookups (hb_closure_lookups_context_t *c) const {}

  void collect_glyphs (hb_collect_glyphs_context_t *c) const
  {
    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
    + hb_zip (this+coverage, sequence)
    | hb_map (hb_second)
    | hb_map (hb_add (this))
    | hb_apply ([c] (const Sequence &_) { _.collect_glyphs (c); })
    ;
  }

  const Coverage &get_coverage () const { return this+coverage; }

  bool would_apply (hb_would_apply_context_t *c) const
  { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);

    unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);
    if (likely (index == NOT_COVERED)) return_trace (false);

    return_trace ((this+sequence[index]).apply (c));
  }

  bool serialize (hb_serialize_context_t *c,
		  hb_sorted_array_t<const HBGlyphID> glyphs,
		  hb_array_t<const unsigned int> substitute_len_list,
		  hb_array_t<const HBGlyphID> substitute_glyphs_list)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!c->extend_min (*this))) return_trace (false);
    if (unlikely (!sequence.serialize (c, glyphs.length))) return_trace (false);
    for (unsigned int i = 0; i < glyphs.length; i++)
    {
      unsigned int substitute_len = substitute_len_list[i];
      if (unlikely (!sequence[i].serialize (c, this)
				.serialize (c, substitute_glyphs_list.sub_array (0, substitute_len))))
	return_trace (false);
      substitute_glyphs_list += substitute_len;
    }
    return_trace (coverage.serialize (c, this).serialize (c, glyphs));
  }

  bool subset (hb_subset_context_t *c) const
  {
    TRACE_SUBSET (this);
    const hb_set_t &glyphset = *c->plan->glyphset ();
    const hb_map_t &glyph_map = *c->plan->glyph_map;

    auto *out = c->serializer->start_embed (*this);
    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
    out->format = format;

    hb_sorted_vector_t<hb_codepoint_t> new_coverage;
    + hb_zip (this+coverage, sequence)
    | hb_filter (glyphset, hb_first)
    | hb_filter (subset_offset_array (c, out->sequence, this), hb_second)
    | hb_map (hb_first)
    | hb_map (glyph_map)
    | hb_sink (new_coverage)
    ;
    out->coverage.serialize (c->serializer, out)
		 .serialize (c->serializer, new_coverage.iter ());
    return_trace (bool (new_coverage));
  }

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (coverage.sanitize (c, this) && sequence.sanitize (c, this));
  }

  protected:
  HBUINT16	format;			/* Format identifier--format = 1 */
  OffsetTo<Coverage>
		coverage;		/* Offset to Coverage table--from
					 * beginning of Substitution table */
  OffsetArrayOf<Sequence>
		sequence;		/* Array of Sequence tables
					 * ordered by Coverage Index */
  public:
  DEFINE_SIZE_ARRAY (6, sequence);
};

struct MultipleSubst
{
  bool serialize (hb_serialize_context_t *c,
		  hb_sorted_array_t<const HBGlyphID> glyphs,
		  hb_array_t<const unsigned int> substitute_len_list,
		  hb_array_t<const HBGlyphID> substitute_glyphs_list)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!c->extend_min (u.format))) return_trace (false);
    unsigned int format = 1;
    u.format = format;
    switch (u.format) {
    case 1: return_trace (u.format1.serialize (c, glyphs, substitute_len_list, substitute_glyphs_list));
    default:return_trace (false);
    }
  }

  template <typename context_t, typename ...Ts>
  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
  {
    TRACE_DISPATCH (this, u.format);
    if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
    switch (u.format) {
    case 1: return_trace (c->dispatch (u.format1, hb_forward<Ts> (ds)...));
    default:return_trace (c->default_return_value ());
    }
  }

  protected:
  union {
  HBUINT16		format;		/* Format identifier */
  MultipleSubstFormat1	format1;
  } u;
};

struct AlternateSet
{
  bool intersects (const hb_set_t *glyphs) const
  { return hb_any (alternates, glyphs); }

  void closure (hb_closure_context_t *c) const
  { c->output->add_array (alternates.arrayZ, alternates.len); }

  void collect_glyphs (hb_collect_glyphs_context_t *c) const
  { c->output->add_array (alternates.arrayZ, alternates.len); }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);
    unsigned int count = alternates.len;

    if (unlikely (!count)) return_trace (false);

    hb_mask_t glyph_mask = c->buffer->cur().mask;
    hb_mask_t lookup_mask = c->lookup_mask;

    /* Note: This breaks badly if two features enabled this lookup together. */
    unsigned int shift = hb_ctz (lookup_mask);
    unsigned int alt_index = ((lookup_mask & glyph_mask) >> shift);

    /* If alt_index is MAX_VALUE, randomize feature if it is the rand feature. */
    if (alt_index == HB_OT_MAP_MAX_VALUE && c->random)
      alt_index = c->random_number () % count + 1;

    if (unlikely (alt_index > count || alt_index == 0)) return_trace (false);

    c->replace_glyph (alternates[alt_index - 1]);

    return_trace (true);
  }

  template <typename Iterator,
	    hb_requires (hb_is_source_of (Iterator, hb_codepoint_t))>
  bool serialize (hb_serialize_context_t *c,
		  Iterator alts)
  {
    TRACE_SERIALIZE (this);
    return_trace (alternates.serialize (c, alts));
  }

  bool subset (hb_subset_context_t *c) const
  {
    TRACE_SUBSET (this);
    const hb_set_t &glyphset = *c->plan->glyphset ();
    const hb_map_t &glyph_map = *c->plan->glyph_map;

    auto it =
      + hb_iter (alternates)
      | hb_filter (glyphset)
      | hb_map (glyph_map)
      ;

    auto *out = c->serializer->start_embed (*this);
    return_trace (out->serialize (c->serializer, it) &&
		  out->alternates);
  }

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (alternates.sanitize (c));
  }

  protected:
  ArrayOf<HBGlyphID>
		alternates;		/* Array of alternate GlyphIDs--in
					 * arbitrary order */
  public:
  DEFINE_SIZE_ARRAY (2, alternates);
};

struct AlternateSubstFormat1
{
  bool intersects (const hb_set_t *glyphs) const
  { return (this+coverage).intersects (glyphs); }

  void closure (hb_closure_context_t *c) const
  {
    + hb_zip (this+coverage, alternateSet)
    | hb_filter (c->glyphs, hb_first)
    | hb_map (hb_second)
    | hb_map (hb_add (this))
    | hb_apply ([c] (const AlternateSet &_) { _.closure (c); })
    ;
  }

  void closure_lookups (hb_closure_lookups_context_t *c) const {}

  void collect_glyphs (hb_collect_glyphs_context_t *c) const
  {
    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
    + hb_zip (this+coverage, alternateSet)
    | hb_map (hb_second)
    | hb_map (hb_add (this))
    | hb_apply ([c] (const AlternateSet &_) { _.collect_glyphs (c); })
    ;
  }

  const Coverage &get_coverage () const { return this+coverage; }

  bool would_apply (hb_would_apply_context_t *c) const
  { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);

    unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);
    if (likely (index == NOT_COVERED)) return_trace (false);

    return_trace ((this+alternateSet[index]).apply (c));
  }

  bool serialize (hb_serialize_context_t *c,
		  hb_sorted_array_t<const HBGlyphID> glyphs,
		  hb_array_t<const unsigned int> alternate_len_list,
		  hb_array_t<const HBGlyphID> alternate_glyphs_list)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!c->extend_min (*this))) return_trace (false);
    if (unlikely (!alternateSet.serialize (c, glyphs.length))) return_trace (false);
    for (unsigned int i = 0; i < glyphs.length; i++)
    {
      unsigned int alternate_len = alternate_len_list[i];
      if (unlikely (!alternateSet[i].serialize (c, this)
				    .serialize (c, alternate_glyphs_list.sub_array (0, alternate_len))))
	return_trace (false);
      alternate_glyphs_list += alternate_len;
    }
    return_trace (coverage.serialize (c, this).serialize (c, glyphs));
  }

  bool subset (hb_subset_context_t *c) const
  {
    TRACE_SUBSET (this);
    const hb_set_t &glyphset = *c->plan->glyphset ();
    const hb_map_t &glyph_map = *c->plan->glyph_map;

    auto *out = c->serializer->start_embed (*this);
    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
    out->format = format;

    hb_sorted_vector_t<hb_codepoint_t> new_coverage;
    + hb_zip (this+coverage, alternateSet)
    | hb_filter (glyphset, hb_first)
    | hb_filter (subset_offset_array (c, out->alternateSet, this), hb_second)
    | hb_map (hb_first)
    | hb_map (glyph_map)
    | hb_sink (new_coverage)
    ;
    out->coverage.serialize (c->serializer, out)
		 .serialize (c->serializer, new_coverage.iter ());
    return_trace (bool (new_coverage));
  }

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (coverage.sanitize (c, this) && alternateSet.sanitize (c, this));
  }

  protected:
  HBUINT16	format;			/* Format identifier--format = 1 */
  OffsetTo<Coverage>
		coverage;		/* Offset to Coverage table--from
					 * beginning of Substitution table */
  OffsetArrayOf<AlternateSet>
		alternateSet;		/* Array of AlternateSet tables
					 * ordered by Coverage Index */
  public:
  DEFINE_SIZE_ARRAY (6, alternateSet);
};

struct AlternateSubst
{
  bool serialize (hb_serialize_context_t *c,
		  hb_sorted_array_t<const HBGlyphID> glyphs,
		  hb_array_t<const unsigned int> alternate_len_list,
		  hb_array_t<const HBGlyphID> alternate_glyphs_list)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!c->extend_min (u.format))) return_trace (false);
    unsigned int format = 1;
    u.format = format;
    switch (u.format) {
    case 1: return_trace (u.format1.serialize (c, glyphs, alternate_len_list, alternate_glyphs_list));
    default:return_trace (false);
    }
  }

  template <typename context_t, typename ...Ts>
  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
  {
    TRACE_DISPATCH (this, u.format);
    if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
    switch (u.format) {
    case 1: return_trace (c->dispatch (u.format1, hb_forward<Ts> (ds)...));
    default:return_trace (c->default_return_value ());
    }
  }

  protected:
  union {
  HBUINT16		format;		/* Format identifier */
  AlternateSubstFormat1	format1;
  } u;
};

struct Ligature
{
  bool intersects (const hb_set_t *glyphs) const
  { return hb_all (component, glyphs); }

  void closure (hb_closure_context_t *c) const
  {
    if (!intersects (c->glyphs)) return;
    c->output->add (ligGlyph);
  }

  void collect_glyphs (hb_collect_glyphs_context_t *c) const
  {
    c->input->add_array (component.arrayZ, component.get_length ());
    c->output->add (ligGlyph);
  }

  bool would_apply (hb_would_apply_context_t *c) const
  {
    if (c->len != component.lenP1)
      return false;

    for (unsigned int i = 1; i < c->len; i++)
      if (likely (c->glyphs[i] != component[i]))
	return false;

    return true;
  }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);
    unsigned int count = component.lenP1;

    if (unlikely (!count)) return_trace (false);

    /* Special-case to make it in-place and not consider this
     * as a "ligated" substitution. */
    if (unlikely (count == 1))
    {
      c->replace_glyph (ligGlyph);
      return_trace (true);
    }

    unsigned int total_component_count = 0;

    unsigned int match_length = 0;
    unsigned int match_positions[HB_MAX_CONTEXT_LENGTH];

    if (likely (!match_input (c, count,
			      &component[1],
			      match_glyph,
			      nullptr,
			      &match_length,
			      match_positions,
			      &total_component_count)))
      return_trace (false);

    ligate_input (c,
		  count,
		  match_positions,
		  match_length,
		  ligGlyph,
		  total_component_count);

    return_trace (true);
  }

  template <typename Iterator,
	    hb_requires (hb_is_source_of (Iterator, hb_codepoint_t))>
  bool serialize (hb_serialize_context_t *c,
		  hb_codepoint_t ligature,
		  Iterator components /* Starting from second */)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!c->extend_min (*this))) return_trace (false);
    ligGlyph = ligature;
    if (unlikely (!component.serialize (c, components))) return_trace (false);
    return_trace (true);
  }

  bool subset (hb_subset_context_t *c) const
  {
    TRACE_SUBSET (this);
    const hb_set_t &glyphset = *c->plan->glyphset ();
    const hb_map_t &glyph_map = *c->plan->glyph_map;

    if (!intersects (&glyphset) || !glyphset.has (ligGlyph)) return_trace (false);

    auto it =
      + hb_iter (component)
      | hb_map (glyph_map)
      ;

    auto *out = c->serializer->start_embed (*this);
    return_trace (out->serialize (c->serializer,
				   glyph_map[ligGlyph],
				   it));
  }

  public:
  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (ligGlyph.sanitize (c) && component.sanitize (c));
  }

  protected:
  HBGlyphID	ligGlyph;		/* GlyphID of ligature to substitute */
  HeadlessArrayOf<HBGlyphID>
		component;		/* Array of component GlyphIDs--start
					 * with the second  component--ordered
					 * in writing direction */
  public:
  DEFINE_SIZE_ARRAY (4, component);
};

struct LigatureSet
{
  bool intersects (const hb_set_t *glyphs) const
  {
    return
    + hb_iter (ligature)
    | hb_map (hb_add (this))
    | hb_map ([glyphs] (const Ligature &_) { return _.intersects (glyphs); })
    | hb_any
    ;
  }

  void closure (hb_closure_context_t *c) const
  {
    + hb_iter (ligature)
    | hb_map (hb_add (this))
    | hb_apply ([c] (const Ligature &_) { _.closure (c); })
    ;
  }

  void collect_glyphs (hb_collect_glyphs_context_t *c) const
  {
    + hb_iter (ligature)
    | hb_map (hb_add (this))
    | hb_apply ([c] (const Ligature &_) { _.collect_glyphs (c); })
    ;
  }

  bool would_apply (hb_would_apply_context_t *c) const
  {
    return
    + hb_iter (ligature)
    | hb_map (hb_add (this))
    | hb_map ([c] (const Ligature &_) { return _.would_apply (c); })
    | hb_any
    ;
  }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);
    unsigned int num_ligs = ligature.len;
    for (unsigned int i = 0; i < num_ligs; i++)
    {
      const Ligature &lig = this+ligature[i];
      if (lig.apply (c)) return_trace (true);
    }

    return_trace (false);
  }

  bool serialize (hb_serialize_context_t *c,
		  hb_array_t<const HBGlyphID> ligatures,
		  hb_array_t<const unsigned int> component_count_list,
		  hb_array_t<const HBGlyphID> &component_list /* Starting from second for each ligature */)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!c->extend_min (*this))) return_trace (false);
    if (unlikely (!ligature.serialize (c, ligatures.length))) return_trace (false);
    for (unsigned int i = 0; i < ligatures.length; i++)
    {
      unsigned int component_count = (unsigned) hb_max ((int) component_count_list[i] - 1, 0);
      if (unlikely (!ligature[i].serialize (c, this)
				.serialize (c,
					    ligatures[i],
					    component_list.sub_array (0, component_count))))
	return_trace (false);
      component_list += component_count;
    }
    return_trace (true);
  }

  bool subset (hb_subset_context_t *c) const
  {
    TRACE_SUBSET (this);
    auto *out = c->serializer->start_embed (*this);
    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);

    + hb_iter (ligature)
    | hb_filter (subset_offset_array (c, out->ligature, this))
    | hb_drain
    ;
    return_trace (bool (out->ligature));
  }

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (ligature.sanitize (c, this));
  }

  protected:
  OffsetArrayOf<Ligature>
		ligature;		/* Array LigatureSet tables
					 * ordered by preference */
  public:
  DEFINE_SIZE_ARRAY (2, ligature);
};

struct LigatureSubstFormat1
{
  bool intersects (const hb_set_t *glyphs) const
  {
    return
    + hb_zip (this+coverage, ligatureSet)
    | hb_filter (*glyphs, hb_first)
    | hb_map (hb_second)
    | hb_map ([this, glyphs] (const OffsetTo<LigatureSet> &_)
	      { return (this+_).intersects (glyphs); })
    | hb_any
    ;
  }

  void closure (hb_closure_context_t *c) const
  {
    + hb_zip (this+coverage, ligatureSet)
    | hb_filter (*c->glyphs, hb_first)
    | hb_map (hb_second)
    | hb_map (hb_add (this))
    | hb_apply ([c] (const LigatureSet &_) { _.closure (c); })
    ;
  }

  void closure_lookups (hb_closure_lookups_context_t *c) const {}

  void collect_glyphs (hb_collect_glyphs_context_t *c) const
  {
    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;

    + hb_zip (this+coverage, ligatureSet)
    | hb_map (hb_second)
    | hb_map (hb_add (this))
    | hb_apply ([c] (const LigatureSet &_) { _.collect_glyphs (c); })
    ;
  }

  const Coverage &get_coverage () const { return this+coverage; }

  bool would_apply (hb_would_apply_context_t *c) const
  {
    unsigned int index = (this+coverage).get_coverage (c->glyphs[0]);
    if (likely (index == NOT_COVERED)) return false;

    const LigatureSet &lig_set = this+ligatureSet[index];
    return lig_set.would_apply (c);
  }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);

    unsigned int index = (this+coverage).get_coverage (c->buffer->cur ().codepoint);
    if (likely (index == NOT_COVERED)) return_trace (false);

    const LigatureSet &lig_set = this+ligatureSet[index];
    return_trace (lig_set.apply (c));
  }

  bool serialize (hb_serialize_context_t *c,
		  hb_sorted_array_t<const HBGlyphID> first_glyphs,
		  hb_array_t<const unsigned int> ligature_per_first_glyph_count_list,
		  hb_array_t<const HBGlyphID> ligatures_list,
		  hb_array_t<const unsigned int> component_count_list,
		  hb_array_t<const HBGlyphID> component_list /* Starting from second for each ligature */)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!c->extend_min (*this))) return_trace (false);
    if (unlikely (!ligatureSet.serialize (c, first_glyphs.length))) return_trace (false);
    for (unsigned int i = 0; i < first_glyphs.length; i++)
    {
      unsigned int ligature_count = ligature_per_first_glyph_count_list[i];
      if (unlikely (!ligatureSet[i].serialize (c, this)
				   .serialize (c,
					       ligatures_list.sub_array (0, ligature_count),
					       component_count_list.sub_array (0, ligature_count),
					       component_list))) return_trace (false);
      ligatures_list += ligature_count;
      component_count_list += ligature_count;
    }
    return_trace (coverage.serialize (c, this).serialize (c, first_glyphs));
  }

  bool subset (hb_subset_context_t *c) const
  {
    TRACE_SUBSET (this);
    const hb_set_t &glyphset = *c->plan->glyphset ();
    const hb_map_t &glyph_map = *c->plan->glyph_map;

    auto *out = c->serializer->start_embed (*this);
    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
    out->format = format;

    hb_sorted_vector_t<hb_codepoint_t> new_coverage;
    + hb_zip (this+coverage, ligatureSet)
    | hb_filter (glyphset, hb_first)
    | hb_filter (subset_offset_array (c, out->ligatureSet, this), hb_second)
    | hb_map (hb_first)
    | hb_map (glyph_map)
    | hb_sink (new_coverage)
    ;
    out->coverage.serialize (c->serializer, out)
		 .serialize (c->serializer, new_coverage.iter ());
    return_trace (bool (new_coverage));
  }

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (coverage.sanitize (c, this) && ligatureSet.sanitize (c, this));
  }

  protected:
  HBUINT16	format;			/* Format identifier--format = 1 */
  OffsetTo<Coverage>
		coverage;		/* Offset to Coverage table--from
					 * beginning of Substitution table */
  OffsetArrayOf<LigatureSet>
		ligatureSet;		/* Array LigatureSet tables
					 * ordered by Coverage Index */
  public:
  DEFINE_SIZE_ARRAY (6, ligatureSet);
};

struct LigatureSubst
{
  bool serialize (hb_serialize_context_t *c,
		  hb_sorted_array_t<const HBGlyphID> first_glyphs,
		  hb_array_t<const unsigned int> ligature_per_first_glyph_count_list,
		  hb_array_t<const HBGlyphID> ligatures_list,
		  hb_array_t<const unsigned int> component_count_list,
		  hb_array_t<const HBGlyphID> component_list /* Starting from second for each ligature */)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!c->extend_min (u.format))) return_trace (false);
    unsigned int format = 1;
    u.format = format;
    switch (u.format) {
    case 1: return_trace (u.format1.serialize (c,
					       first_glyphs,
					       ligature_per_first_glyph_count_list,
					       ligatures_list,
					       component_count_list,
					       component_list));
    default:return_trace (false);
    }
  }

  template <typename context_t, typename ...Ts>
  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
  {
    TRACE_DISPATCH (this, u.format);
    if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
    switch (u.format) {
    case 1: return_trace (c->dispatch (u.format1, hb_forward<Ts> (ds)...));
    default:return_trace (c->default_return_value ());
    }
  }

  protected:
  union {
  HBUINT16		format;		/* Format identifier */
  LigatureSubstFormat1	format1;
  } u;
};

struct ContextSubst : Context {};

struct ChainContextSubst : ChainContext {};

struct ExtensionSubst : Extension<ExtensionSubst>
{
  typedef struct SubstLookupSubTable SubTable;
  bool is_reverse () const;
};

struct ReverseChainSingleSubstFormat1
{
  bool intersects (const hb_set_t *glyphs) const
  {
    if (!(this+coverage).intersects (glyphs))
      return false;

    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage>> (backtrack);

    unsigned int count;

    count = backtrack.len;
    for (unsigned int i = 0; i < count; i++)
      if (!(this+backtrack[i]).intersects (glyphs))
	return false;

    count = lookahead.len;
    for (unsigned int i = 0; i < count; i++)
      if (!(this+lookahead[i]).intersects (glyphs))
	return false;

    return true;
  }

  void closure (hb_closure_context_t *c) const
  {
    if (!intersects (c->glyphs)) return;

    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage>> (backtrack);
    const ArrayOf<HBGlyphID> &substitute = StructAfter<ArrayOf<HBGlyphID>> (lookahead);

    + hb_zip (this+coverage, substitute)
    | hb_filter (*c->glyphs, hb_first)
    | hb_map (hb_second)
    | hb_sink (c->output)
    ;
  }

  void closure_lookups (hb_closure_lookups_context_t *c) const {}

  void collect_glyphs (hb_collect_glyphs_context_t *c) const
  {
    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;

    unsigned int count;

    count = backtrack.len;
    for (unsigned int i = 0; i < count; i++)
      if (unlikely (!(this+backtrack[i]).collect_coverage (c->before))) return;

    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage>> (backtrack);
    count = lookahead.len;
    for (unsigned int i = 0; i < count; i++)
      if (unlikely (!(this+lookahead[i]).collect_coverage (c->after))) return;

    const ArrayOf<HBGlyphID> &substitute = StructAfter<ArrayOf<HBGlyphID>> (lookahead);
    count = substitute.len;
    c->output->add_array (substitute.arrayZ, substitute.len);
  }

  const Coverage &get_coverage () const { return this+coverage; }

  bool would_apply (hb_would_apply_context_t *c) const
  { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);
    if (unlikely (c->nesting_level_left != HB_MAX_NESTING_LEVEL))
      return_trace (false); /* No chaining to this type */

    unsigned int index = (this+coverage).get_coverage (c->buffer->cur ().codepoint);
    if (likely (index == NOT_COVERED)) return_trace (false);

    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage>> (backtrack);
    const ArrayOf<HBGlyphID> &substitute = StructAfter<ArrayOf<HBGlyphID>> (lookahead);

  unsigned int start_index = 0, end_index = 0;
    if (match_backtrack (c,
			 backtrack.len, (HBUINT16 *) backtrack.arrayZ,
			 match_coverage, this,
			 &start_index) &&
	match_lookahead (c,
			 lookahead.len, (HBUINT16 *) lookahead.arrayZ,
			 match_coverage, this,
			 1, &end_index))
    {
      c->buffer->unsafe_to_break_from_outbuffer (start_index, end_index);
      c->replace_glyph_inplace (substitute[index]);
      /* Note: We DON'T decrease buffer->idx.  The main loop does it
       * for us.  This is useful for preventing surprises if someone
       * calls us through a Context lookup. */
      return_trace (true);
    }

    return_trace (false);
  }

  bool subset (hb_subset_context_t *c) const
  {
    TRACE_SUBSET (this);
    // TODO(subset)
    return_trace (false);
  }

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    if (!(coverage.sanitize (c, this) && backtrack.sanitize (c, this)))
      return_trace (false);
    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage>> (backtrack);
    if (!lookahead.sanitize (c, this))
      return_trace (false);
    const ArrayOf<HBGlyphID> &substitute = StructAfter<ArrayOf<HBGlyphID>> (lookahead);
    return_trace (substitute.sanitize (c));
  }

  protected:
  HBUINT16	format;			/* Format identifier--format = 1 */
  OffsetTo<Coverage>
		coverage;		/* Offset to Coverage table--from
					 * beginning of table */
  OffsetArrayOf<Coverage>
		backtrack;		/* Array of coverage tables
					 * in backtracking sequence, in glyph
					 * sequence order */
  OffsetArrayOf<Coverage>
		lookaheadX;		/* Array of coverage tables
					 * in lookahead sequence, in glyph
					 * sequence order */
  ArrayOf<HBGlyphID>
		substituteX;		/* Array of substitute
					 * GlyphIDs--ordered by Coverage Index */
  public:
  DEFINE_SIZE_MIN (10);
};

struct ReverseChainSingleSubst
{
  template <typename context_t, typename ...Ts>
  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
  {
    TRACE_DISPATCH (this, u.format);
    if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
    switch (u.format) {
    case 1: return_trace (c->dispatch (u.format1, hb_forward<Ts> (ds)...));
    default:return_trace (c->default_return_value ());
    }
  }

  protected:
  union {
  HBUINT16				format;		/* Format identifier */
  ReverseChainSingleSubstFormat1	format1;
  } u;
};

/*
 * SubstLookup
 */

struct SubstLookupSubTable
{
  friend struct Lookup;
  friend struct SubstLookup;

  enum Type {
    Single		= 1,
    Multiple		= 2,
    Alternate		= 3,
    Ligature		= 4,
    Context		= 5,
    ChainContext	= 6,
    Extension		= 7,
    ReverseChainSingle	= 8
  };

  template <typename context_t, typename ...Ts>
  typename context_t::return_t dispatch (context_t *c, unsigned int lookup_type, Ts&&... ds) const
  {
    TRACE_DISPATCH (this, lookup_type);
    switch (lookup_type) {
    case Single:		return_trace (u.single.dispatch (c, hb_forward<Ts> (ds)...));
    case Multiple:		return_trace (u.multiple.dispatch (c, hb_forward<Ts> (ds)...));
    case Alternate:		return_trace (u.alternate.dispatch (c, hb_forward<Ts> (ds)...));
    case Ligature:		return_trace (u.ligature.dispatch (c, hb_forward<Ts> (ds)...));
    case Context:		return_trace (u.context.dispatch (c, hb_forward<Ts> (ds)...));
    case ChainContext:		return_trace (u.chainContext.dispatch (c, hb_forward<Ts> (ds)...));
    case Extension:		return_trace (u.extension.dispatch (c, hb_forward<Ts> (ds)...));
    case ReverseChainSingle:	return_trace (u.reverseChainContextSingle.dispatch (c, hb_forward<Ts> (ds)...));
    default:			return_trace (c->default_return_value ());
    }
  }

  bool intersects (const hb_set_t *glyphs, unsigned int lookup_type) const
  {
    hb_intersects_context_t c (glyphs);
    return dispatch (&c, lookup_type);
  }

  protected:
  union {
  SingleSubst			single;
  MultipleSubst			multiple;
  AlternateSubst		alternate;
  LigatureSubst			ligature;
  ContextSubst			context;
  ChainContextSubst		chainContext;
  ExtensionSubst		extension;
  ReverseChainSingleSubst	reverseChainContextSingle;
  } u;
  public:
  DEFINE_SIZE_MIN (0);
};

struct SubstLookup : Lookup
{
  typedef SubstLookupSubTable SubTable;

  const SubTable& get_subtable (unsigned int i) const
  { return Lookup::get_subtable<SubTable> (i); }

  static inline bool lookup_type_is_reverse (unsigned int lookup_type)
  { return lookup_type == SubTable::ReverseChainSingle; }

  bool is_reverse () const
  {
    unsigned int type = get_type ();
    if (unlikely (type == SubTable::Extension))
      return reinterpret_cast<const ExtensionSubst &> (get_subtable (0)).is_reverse ();
    return lookup_type_is_reverse (type);
  }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);
    return_trace (dispatch (c));
  }

  bool intersects (const hb_set_t *glyphs) const
  {
    hb_intersects_context_t c (glyphs);
    return dispatch (&c);
  }

  hb_closure_context_t::return_t closure (hb_closure_context_t *c, unsigned int this_index) const
  {
    if (!c->should_visit_lookup (this_index))
      return hb_closure_context_t::default_return_value ();

    c->set_recurse_func (dispatch_closure_recurse_func);

    hb_closure_context_t::return_t ret = dispatch (c);

    c->flush ();

    return ret;
  }

  hb_closure_lookups_context_t::return_t closure_lookups (hb_closure_lookups_context_t *c, unsigned this_index) const
  {
    if (c->is_lookup_visited (this_index))
      return hb_closure_lookups_context_t::default_return_value ();

    c->set_lookup_visited (this_index);
    if (!intersects (c->glyphs))
    {
      c->set_lookup_inactive (this_index);
      return hb_closure_lookups_context_t::default_return_value ();
    }

    c->set_recurse_func (dispatch_closure_lookups_recurse_func);

    hb_closure_lookups_context_t::return_t ret = dispatch (c);
    return ret;
  }

  hb_collect_glyphs_context_t::return_t collect_glyphs (hb_collect_glyphs_context_t *c) const
  {
    c->set_recurse_func (dispatch_recurse_func<hb_collect_glyphs_context_t>);
    return dispatch (c);
  }

  template <typename set_t>
  void collect_coverage (set_t *glyphs) const
  {
    hb_collect_coverage_context_t<set_t> c (glyphs);
    dispatch (&c);
  }

  bool would_apply (hb_would_apply_context_t *c,
		    const hb_ot_layout_lookup_accelerator_t *accel) const
  {
    if (unlikely (!c->len)) return false;
    if (!accel->may_have (c->glyphs[0])) return false;
      return dispatch (c);
  }

  static inline bool apply_recurse_func (hb_ot_apply_context_t *c, unsigned int lookup_index);

  SubTable& serialize_subtable (hb_serialize_context_t *c,
				unsigned int i)
  { return get_subtables<SubTable> ()[i].serialize (c, this); }

  bool serialize_single (hb_serialize_context_t *c,
			 uint32_t lookup_props,
			 hb_sorted_array_t<const HBGlyphID> glyphs,
			 hb_array_t<const HBGlyphID> substitutes)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!Lookup::serialize (c, SubTable::Single, lookup_props, 1))) return_trace (false);
    return_trace (serialize_subtable (c, 0).u.single.
		  serialize (c, hb_zip (glyphs, substitutes)));
  }

  bool serialize_multiple (hb_serialize_context_t *c,
			   uint32_t lookup_props,
			   hb_sorted_array_t<const HBGlyphID> glyphs,
			   hb_array_t<const unsigned int> substitute_len_list,
			   hb_array_t<const HBGlyphID> substitute_glyphs_list)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!Lookup::serialize (c, SubTable::Multiple, lookup_props, 1))) return_trace (false);
    return_trace (serialize_subtable (c, 0).u.multiple.
		  serialize (c,
			     glyphs,
			     substitute_len_list,
			     substitute_glyphs_list));
  }

  bool serialize_alternate (hb_serialize_context_t *c,
			    uint32_t lookup_props,
			    hb_sorted_array_t<const HBGlyphID> glyphs,
			    hb_array_t<const unsigned int> alternate_len_list,
			    hb_array_t<const HBGlyphID> alternate_glyphs_list)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!Lookup::serialize (c, SubTable::Alternate, lookup_props, 1))) return_trace (false);
    return_trace (serialize_subtable (c, 0).u.alternate.
		  serialize (c,
			     glyphs,
			     alternate_len_list,
			     alternate_glyphs_list));
  }

  bool serialize_ligature (hb_serialize_context_t *c,
			   uint32_t lookup_props,
			   hb_sorted_array_t<const HBGlyphID> first_glyphs,
			   hb_array_t<const unsigned int> ligature_per_first_glyph_count_list,
			   hb_array_t<const HBGlyphID> ligatures_list,
			   hb_array_t<const unsigned int> component_count_list,
			   hb_array_t<const HBGlyphID> component_list /* Starting from second for each ligature */)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!Lookup::serialize (c, SubTable::Ligature, lookup_props, 1))) return_trace (false);
    return_trace (serialize_subtable (c, 0).u.ligature.
		  serialize (c,
			     first_glyphs,
			     ligature_per_first_glyph_count_list,
			     ligatures_list,
			     component_count_list,
			     component_list));
  }

  template <typename context_t>
  static inline typename context_t::return_t dispatch_recurse_func (context_t *c, unsigned int lookup_index);

  static inline hb_closure_context_t::return_t dispatch_closure_recurse_func (hb_closure_context_t *c, unsigned int lookup_index)
  {
    if (!c->should_visit_lookup (lookup_index))
      return hb_empty_t ();

    hb_closure_context_t::return_t ret = dispatch_recurse_func (c, lookup_index);

    /* While in theory we should flush here, it will cause timeouts because a recursive
     * lookup can keep growing the glyph set.  Skip, and outer loop will retry up to
     * HB_CLOSURE_MAX_STAGES time, which should be enough for every realistic font. */
    //c->flush ();

    return ret;
  }

  HB_INTERNAL static hb_closure_lookups_context_t::return_t dispatch_closure_lookups_recurse_func (hb_closure_lookups_context_t *c, unsigned lookup_index);

  template <typename context_t, typename ...Ts>
  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
  { return Lookup::dispatch<SubTable> (c, hb_forward<Ts> (ds)...); }

  bool subset (hb_subset_context_t *c) const
  { return Lookup::subset<SubTable> (c); }

  bool sanitize (hb_sanitize_context_t *c) const
  { return Lookup::sanitize<SubTable> (c); }
};

/*
 * GSUB -- Glyph Substitution
 * https://docs.microsoft.com/en-us/typography/opentype/spec/gsub
 */

struct GSUB : GSUBGPOS
{
  static constexpr hb_tag_t tableTag = HB_OT_TAG_GSUB;

  const SubstLookup& get_lookup (unsigned int i) const
  { return static_cast<const SubstLookup &> (GSUBGPOS::get_lookup (i)); }

  bool subset (hb_subset_context_t *c) const
  {
    hb_subset_layout_context_t l (c, tableTag, c->plan->gsub_lookups, c->plan->gsub_features);
    return GSUBGPOS::subset<SubstLookup> (&l);
  }

  bool sanitize (hb_sanitize_context_t *c) const
  { return GSUBGPOS::sanitize<SubstLookup> (c); }

  HB_INTERNAL bool is_blacklisted (hb_blob_t *blob,
				   hb_face_t *face) const;

  typedef GSUBGPOS::accelerator_t<GSUB> accelerator_t;
};

struct GSUB_accelerator_t : GSUB::accelerator_t {};

/* Out-of-class implementation for methods recursing */

#ifndef HB_NO_OT_LAYOUT
/*static*/ inline bool ExtensionSubst::is_reverse () const
{
  return SubstLookup::lookup_type_is_reverse (get_type ());
}
template <typename context_t>
/*static*/ typename context_t::return_t SubstLookup::dispatch_recurse_func (context_t *c, unsigned int lookup_index)
{
  const SubstLookup &l = c->face->table.GSUB.get_relaxed ()->table->get_lookup (lookup_index);
  return l.dispatch (c);
}

/*static*/ inline hb_closure_lookups_context_t::return_t SubstLookup::dispatch_closure_lookups_recurse_func (hb_closure_lookups_context_t *c, unsigned this_index)
{
  const SubstLookup &l = c->face->table.GSUB.get_relaxed ()->table->get_lookup (this_index);
  return l.closure_lookups (c, this_index);
}

/*static*/ bool SubstLookup::apply_recurse_func (hb_ot_apply_context_t *c, unsigned int lookup_index)
{
  const SubstLookup &l = c->face->table.GSUB.get_relaxed ()->table->get_lookup (lookup_index);
  unsigned int saved_lookup_props = c->lookup_props;
  unsigned int saved_lookup_index = c->lookup_index;
  c->set_lookup_index (lookup_index);
  c->set_lookup_props (l.get_props ());
  bool ret = l.dispatch (c);
  c->set_lookup_index (saved_lookup_index);
  c->set_lookup_props (saved_lookup_props);
  return ret;
}
#endif

} /* namespace OT */

#endif /* HB_OT_LAYOUT_GSUB_TABLE_HH */

repo_language: C

mime_type: text/x-c


text:
/*
 * Copyright © 2007,2008,2009,2010  Red Hat, Inc.
 * Copyright © 2012,2018  Google, Inc.
 *
 *  This is part of HarfBuzz, a text shaping 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
 * Google Author(s): Behdad Esfahbod
 */

#ifndef HB_DISPATCH_HH
#define HB_DISPATCH_HH

#include "hb.hh"

/*
 * Dispatch
 */

template <typename Context, typename Return, unsigned int MaxDebugDepth>
struct hb_dispatch_context_t
{
  private:
  /* https://en.wikipedia.org/wiki/Curiously_recurring_template_pattern */
  const Context* thiz () const { return static_cast<const Context *> (this); }
	Context* thiz ()       { return static_cast<      Context *> (this); }
  public:
  static constexpr unsigned max_debug_depth = MaxDebugDepth;
  typedef Return return_t;
  template <typename T, typename F>
  bool may_dispatch (const T *obj HB_UNUSED, const F *format HB_UNUSED) { return true; }
  template <typename T, typename ...Ts>
  return_t dispatch (const T &obj, Ts&&... ds)
  { return obj.dispatch (thiz (), hb_forward<Ts> (ds)...); }
  static return_t no_dispatch_return_value () { return Context::default_return_value (); }
  static bool stop_sublookup_iteration (const return_t r HB_UNUSED) { return false; }
};

#endif /* HB_DISPATCH_HH */


text:
/*
 * Copyright © 2016  Google, Inc.
 *
 *  This is part of HarfBuzz, a text shaping 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.
 *
 * Google Author(s): Seigo Nonaka, Calder Kitagawa
 */

#ifndef HB_OT_COLOR_CBDT_TABLE_HH
#define HB_OT_COLOR_CBDT_TABLE_HH

#include "hb-open-type.hh"

/*
 * CBLC -- Color Bitmap Location
 * https://docs.microsoft.com/en-us/typography/opentype/spec/cblc
 * https://docs.microsoft.com/en-us/typography/opentype/spec/eblc
 * CBDT -- Color Bitmap Data
 * https://docs.microsoft.com/en-us/typography/opentype/spec/cbdt
 * https://docs.microsoft.com/en-us/typography/opentype/spec/ebdt
 */
#define HB_OT_TAG_CBLC HB_TAG('C','B','L','C')
#define HB_OT_TAG_CBDT HB_TAG('C','B','D','T')

namespace OT {

struct cblc_bitmap_size_subset_context_t
{
  const char *cbdt;
  unsigned int cbdt_length;
  hb_vector_t<char> *cbdt_prime;
  unsigned int size;		/* INOUT
				 *  Input: old size of IndexSubtable
				 *  Output: new size of IndexSubtable
				 */
  unsigned int num_tables;	/* INOUT
				 *  Input: old number of subtables.
				 *  Output: new number of subtables.
				 */
  hb_codepoint_t start_glyph;	/* OUT */
  hb_codepoint_t end_glyph;	/* OUT */
};

static inline bool
_copy_data_to_cbdt (hb_vector_t<char> *cbdt_prime,
		    const void        *data,
		    unsigned           length)
{
  unsigned int new_len = cbdt_prime->length + length;
  if (unlikely (!cbdt_prime->alloc (new_len))) return false;
  memcpy (cbdt_prime->arrayZ + cbdt_prime->length, data, length);
  cbdt_prime->length = new_len;
  return true;
}

struct SmallGlyphMetrics
{
  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this));
  }

  void get_extents (hb_font_t *font, hb_glyph_extents_t *extents) const
  {
    extents->x_bearing = font->em_scale_x (bearingX);
    extents->y_bearing = font->em_scale_y (bearingY);
    extents->width = font->em_scale_x (width);
    extents->height = font->em_scale_y (-static_cast<int>(height));
  }

  HBUINT8	height;
  HBUINT8	width;
  HBINT8	bearingX;
  HBINT8	bearingY;
  HBUINT8	advance;
  public:
  DEFINE_SIZE_STATIC (5);
};

struct BigGlyphMetrics : SmallGlyphMetrics
{
  HBINT8	vertBearingX;
  HBINT8	vertBearingY;
  HBUINT8	vertAdvance;
  public:
  DEFINE_SIZE_STATIC (8);
};

struct SBitLineMetrics
{
  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this));
  }

  HBINT8	ascender;
  HBINT8	decender;
  HBUINT8	widthMax;
  HBINT8	caretSlopeNumerator;
  HBINT8	caretSlopeDenominator;
  HBINT8	caretOffset;
  HBINT8	minOriginSB;
  HBINT8	minAdvanceSB;
  HBINT8	maxBeforeBL;
  HBINT8	minAfterBL;
  HBINT8	padding1;
  HBINT8	padding2;
  public:
  DEFINE_SIZE_STATIC (12);
};

/*
 * Index Subtables.
 */

struct IndexSubtableHeader
{
  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this));
  }

  HBUINT16	indexFormat;
  HBUINT16	imageFormat;
  HBUINT32	imageDataOffset;
  public:
  DEFINE_SIZE_STATIC (8);
};

template <typename OffsetType>
struct IndexSubtableFormat1Or3
{
  bool sanitize (hb_sanitize_context_t *c, unsigned int glyph_count) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  offsetArrayZ.sanitize (c, glyph_count + 1));
  }

  bool get_image_data (unsigned int idx,
		       unsigned int *offset,
		       unsigned int *length) const
  {
    if (unlikely (offsetArrayZ[idx + 1] <= offsetArrayZ[idx]))
      return false;

    *offset = header.imageDataOffset + offsetArrayZ[idx];
    *length = offsetArrayZ[idx + 1] - offsetArrayZ[idx];
    return true;
  }

  bool add_offset (hb_serialize_context_t *c,
		   unsigned int offset,
		   unsigned int *size /* OUT (accumulated) */)
  {
    TRACE_SERIALIZE (this);
    Offset<OffsetType> embedded_offset;
    embedded_offset = offset;
    *size += sizeof (OffsetType);
    auto *o = c->embed (embedded_offset);
    return_trace ((bool) o);
  }

  IndexSubtableHeader	header;
  UnsizedArrayOf<Offset<OffsetType>>
			offsetArrayZ;
  public:
  DEFINE_SIZE_ARRAY (8, offsetArrayZ);
};

struct IndexSubtableFormat1 : IndexSubtableFormat1Or3<HBUINT32> {};
struct IndexSubtableFormat3 : IndexSubtableFormat1Or3<HBUINT16> {};

struct IndexSubtable
{
  bool sanitize (hb_sanitize_context_t *c, unsigned int glyph_count) const
  {
    TRACE_SANITIZE (this);
    if (!u.header.sanitize (c)) return_trace (false);
    switch (u.header.indexFormat)
    {
    case 1: return_trace (u.format1.sanitize (c, glyph_count));
    case 3: return_trace (u.format3.sanitize (c, glyph_count));
    default:return_trace (true);
    }
  }

  bool
  finish_subtable (hb_serialize_context_t *c,
		   unsigned int cbdt_prime_len,
		   unsigned int num_glyphs,
		   unsigned int *size /* OUT (accumulated) */)
  {
    TRACE_SERIALIZE (this);

    unsigned int local_offset = cbdt_prime_len - u.header.imageDataOffset;
    switch (u.header.indexFormat)
    {
    case 1: return_trace (u.format1.add_offset (c, local_offset, size));
    case 3: {
      if (!u.format3.add_offset (c, local_offset, size))
	return_trace (false);
      if (!(num_glyphs & 0x01))  // Pad to 32-bit alignment if needed.
	return_trace (u.format3.add_offset (c, 0, size));
      return_trace (true);
    }
    // TODO: implement 2, 4, 5.
    case 2: case 4:  // No-op.
    case 5:  // Pad to 32-bit aligned.
    default: return_trace (false);
    }
  }

  bool
  fill_missing_glyphs (hb_serialize_context_t *c,
		       unsigned int cbdt_prime_len,
		       unsigned int num_missing,
		       unsigned int *size /* OUT (accumulated) */,
		       unsigned int *num_glyphs /* OUT (accumulated) */)
  {
    TRACE_SERIALIZE (this);

    unsigned int local_offset = cbdt_prime_len - u.header.imageDataOffset;
    switch (u.header.indexFormat)
    {
    case 1: {
      for (unsigned int i = 0; i < num_missing; i++)
      {
	if (unlikely (!u.format1.add_offset (c, local_offset, size)))
	  return_trace (false);
	*num_glyphs += 1;
      }
      return_trace (true);
    }
    case 3: {
      for (unsigned int i = 0; i < num_missing; i++)
      {
	if (unlikely (!u.format3.add_offset (c, local_offset, size)))
	  return_trace (false);
	*num_glyphs += 1;
      }
      return_trace (true);
    }
    // TODO: implement 2, 4, 5.
    case 2:  // Add empty space in cbdt_prime?.
    case 4: case 5:  // No-op as sparse is supported.
    default: return_trace (false);
    }
  }

  bool
  copy_glyph_at_idx (hb_serialize_context_t *c, unsigned int idx,
		     const char *cbdt, unsigned int cbdt_length,
		     hb_vector_t<char> *cbdt_prime /* INOUT */,
		     IndexSubtable *subtable_prime /* INOUT */,
		     unsigned int *size /* OUT (accumulated) */) const
  {
    TRACE_SERIALIZE (this);

    unsigned int offset, length, format;
    if (unlikely (!get_image_data (idx, &offset, &length, &format))) return_trace (false);
    if (unlikely (offset > cbdt_length || cbdt_length - offset < length)) return_trace (false);

    auto *header_prime = subtable_prime->get_header ();
    unsigned int new_local_offset = cbdt_prime->length - (unsigned int) header_prime->imageDataOffset;
    if (unlikely (!_copy_data_to_cbdt (cbdt_prime, cbdt + offset, length))) return_trace (false);

    return_trace (subtable_prime->add_offset (c, new_local_offset, size));
  }

  bool
  add_offset (hb_serialize_context_t *c, unsigned int local_offset,
	      unsigned int *size /* OUT (accumulated) */)
  {
    TRACE_SERIALIZE (this);
    switch (u.header.indexFormat)
    {
    case 1: return_trace (u.format1.add_offset (c, local_offset, size));
    case 3: return_trace (u.format3.add_offset (c, local_offset, size));
    // TODO: Implement tables 2, 4, 5
    case 2:  // Should be a no-op.
    case 4: case 5:  // Handle sparse cases.
    default: return_trace (false);
    }
  }

  bool get_extents (hb_glyph_extents_t *extents HB_UNUSED) const
  {
    switch (u.header.indexFormat)
    {
    case 2: case 5: /* TODO */
    case 1: case 3: case 4: /* Variable-metrics formats do not have metrics here. */
    default:return (false);
    }
  }

  bool
  get_image_data (unsigned int idx, unsigned int *offset,
		  unsigned int *length, unsigned int *format) const
  {
    *format = u.header.imageFormat;
    switch (u.header.indexFormat)
    {
    case 1: return u.format1.get_image_data (idx, offset, length);
    case 3: return u.format3.get_image_data (idx, offset, length);
    default: return false;
    }
  }

  const IndexSubtableHeader* get_header () const { return &u.header; }

  void populate_header (unsigned index_format,
			unsigned image_format,
			unsigned int image_data_offset,
			unsigned int *size)
  {
    u.header.indexFormat = index_format;
    u.header.imageFormat = image_format;
    u.header.imageDataOffset = image_data_offset;
    switch (u.header.indexFormat)
    {
    case 1: *size += IndexSubtableFormat1::min_size; break;
    case 3: *size += IndexSubtableFormat3::min_size; break;
    }
  }

  protected:
  union {
  IndexSubtableHeader	header;
  IndexSubtableFormat1	format1;
  IndexSubtableFormat3	format3;
  /* TODO: Format 2, 4, 5. */
  } u;
  public:
  DEFINE_SIZE_UNION (8, header);
};

struct IndexSubtableRecord
{
  bool sanitize (hb_sanitize_context_t *c, const void *base) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  firstGlyphIndex <= lastGlyphIndex &&
		  offsetToSubtable.sanitize (c, base, lastGlyphIndex - firstGlyphIndex + 1));
  }

  const IndexSubtable* get_subtable (const void *base) const
  {
    return &(base+offsetToSubtable);
  }

  bool add_new_subtable (hb_subset_context_t* c,
			 cblc_bitmap_size_subset_context_t *bitmap_size_context,
			 IndexSubtableRecord *record,
			 const hb_vector_t<hb_pair_t<hb_codepoint_t, const IndexSubtableRecord*>> *lookup, /* IN */
			 const void *base,
			 unsigned int *start /* INOUT */) const
  {
    TRACE_SERIALIZE (this);

    auto *subtable = c->serializer->start_embed<IndexSubtable> ();
    if (unlikely (!subtable)) return_trace (false);
    if (unlikely (!c->serializer->extend_min (subtable))) return_trace (false);

    auto *old_subtable = get_subtable (base);
    auto *old_header = old_subtable->get_header ();

    subtable->populate_header (old_header->indexFormat,
			       old_header->imageFormat,
			       bitmap_size_context->cbdt_prime->length,
			       &bitmap_size_context->size);

    unsigned int num_glyphs = 0;
    bool early_exit = false;
    for (unsigned int i = *start; i < lookup->length; i++)
    {
      hb_codepoint_t new_gid = (*lookup)[i].first;
      const IndexSubtableRecord *next_record = (*lookup)[i].second;
      const IndexSubtable *next_subtable = next_record->get_subtable (base);
      auto *next_header = next_subtable->get_header ();
      if (next_header != old_header)
      {
	*start = i;
	early_exit = true;
	break;
      }
      unsigned int num_missing = record->add_glyph_for_subset (new_gid);
      if (unlikely (!subtable->fill_missing_glyphs (c->serializer,
						    bitmap_size_context->cbdt_prime->length,
						    num_missing,
						    &bitmap_size_context->size,
						    &num_glyphs)))
	return_trace (false);

      hb_codepoint_t old_gid = 0;
      c->plan->old_gid_for_new_gid (new_gid, &old_gid);
      if (old_gid < next_record->firstGlyphIndex)
	return_trace (false);

      unsigned int old_idx = (unsigned int) old_gid - next_record->firstGlyphIndex;
      if (unlikely (!next_subtable->copy_glyph_at_idx (c->serializer,
						       old_idx,
						       bitmap_size_context->cbdt,
						       bitmap_size_context->cbdt_length,
						       bitmap_size_context->cbdt_prime,
						       subtable,
						       &bitmap_size_context->size)))
	return_trace (false);
      num_glyphs += 1;
    }
    if (!early_exit)
      *start = lookup->length;
    if (unlikely (!subtable->finish_subtable (c->serializer,
					      bitmap_size_context->cbdt_prime->length,
					      num_glyphs,
					      &bitmap_size_context->size)))
      return_trace (false);
    return_trace (true);
  }

  bool add_new_record (hb_subset_context_t *c,
		       cblc_bitmap_size_subset_context_t *bitmap_size_context,
		       const hb_vector_t<hb_pair_t<hb_codepoint_t, const IndexSubtableRecord*>> *lookup, /* IN */
		       const void *base,
		       unsigned int *start, /* INOUT */
		       hb_vector_t<IndexSubtableRecord>* records /* INOUT */) const
  {
    TRACE_SERIALIZE (this);
    auto snap = c->serializer->snapshot ();
    unsigned int old_size = bitmap_size_context->size;
    unsigned int old_cbdt_prime_length = bitmap_size_context->cbdt_prime->length;

    // Set to invalid state to indicate filling glyphs is not yet started.
    records->resize (records->length + 1);
    (*records)[records->length - 1].firstGlyphIndex = 1;
    (*records)[records->length - 1].lastGlyphIndex = 0;
    bitmap_size_context->size += IndexSubtableRecord::min_size;

    c->serializer->push ();

    if (unlikely (!add_new_subtable (c, bitmap_size_context, &((*records)[records->length - 1]), lookup, base, start)))
    {
      c->serializer->pop_discard ();
      c->serializer->revert (snap);
      bitmap_size_context->cbdt_prime->shrink (old_cbdt_prime_length);
      bitmap_size_context->size = old_size;
      records->resize (records->length - 1);
      return_trace (false);
    }

    bitmap_size_context->num_tables += 1;
    return_trace (true);
  }

  unsigned int add_glyph_for_subset (hb_codepoint_t gid)
  {
    if (firstGlyphIndex > lastGlyphIndex)
    {
      firstGlyphIndex = gid;
      lastGlyphIndex = gid;
      return 0;
    }
    // TODO maybe assert? this shouldn't occur.
    if (lastGlyphIndex > gid)
      return 0;
    unsigned int num_missing = (unsigned int) (gid - lastGlyphIndex - 1);
    lastGlyphIndex = gid;
    return num_missing;
  }

  bool get_extents (hb_glyph_extents_t *extents, const void *base) const
  { return (base+offsetToSubtable).get_extents (extents); }

  bool get_image_data (unsigned int  gid,
		       const void   *base,
		       unsigned int *offset,
		       unsigned int *length,
		       unsigned int *format) const
  {
    if (gid < firstGlyphIndex || gid > lastGlyphIndex) return false;
    return (base+offsetToSubtable).get_image_data (gid - firstGlyphIndex,
						   offset, length, format);
  }

  HBGlyphID			firstGlyphIndex;
  HBGlyphID			lastGlyphIndex;
  LOffsetTo<IndexSubtable>	offsetToSubtable;
  public:
  DEFINE_SIZE_STATIC (8);
};

struct IndexSubtableArray
{
  friend struct CBDT;

  bool sanitize (hb_sanitize_context_t *c, unsigned int count) const
  {
    TRACE_SANITIZE (this);
    return_trace (indexSubtablesZ.sanitize (c, count, this));
  }

  void
  build_lookup (hb_subset_context_t *c, cblc_bitmap_size_subset_context_t *bitmap_size_context,
		hb_vector_t<hb_pair_t<hb_codepoint_t,
		const IndexSubtableRecord*>> *lookup /* OUT */) const
  {
    bool start_glyph_is_set = false;
    for (hb_codepoint_t new_gid = 0; new_gid < c->plan->num_output_glyphs (); new_gid++)
    {
      hb_codepoint_t old_gid;
      if (unlikely (!c->plan->old_gid_for_new_gid (new_gid, &old_gid))) continue;

      const IndexSubtableRecord* record = find_table (old_gid, bitmap_size_context->num_tables);
      if (unlikely (!record)) continue;

      // Don't add gaps to the lookup. The best way to determine if a glyph is a
      // gap is that it has no image data.
      unsigned int offset, length, format;
      if (unlikely (!record->get_image_data (old_gid, this, &offset, &length, &format))) continue;

      lookup->push (hb_pair_t<hb_codepoint_t, const IndexSubtableRecord*> (new_gid, record));

      if (!start_glyph_is_set)
      {
	bitmap_size_context->start_glyph = new_gid;
	start_glyph_is_set = true;
      }

      bitmap_size_context->end_glyph = new_gid;
    }
  }

  bool
  subset (hb_subset_context_t *c,
	  cblc_bitmap_size_subset_context_t *bitmap_size_context) const
  {
    TRACE_SUBSET (this);

    auto *dst = c->serializer->start_embed<IndexSubtableArray> ();
    if (unlikely (!dst)) return_trace (false);

    hb_vector_t<hb_pair_t<hb_codepoint_t, const IndexSubtableRecord*>> lookup;
    build_lookup (c, bitmap_size_context, &lookup);

    bitmap_size_context->size = 0;
    bitmap_size_context->num_tables = 0;
    hb_vector_t<IndexSubtableRecord> records;
    for (unsigned int start = 0; start < lookup.length;)
    {
      if (unlikely (!lookup[start].second->add_new_record (c, bitmap_size_context, &lookup, this, &start, &records)))
      {
	// Discard any leftover pushes to the serializer from successful records.
	for (unsigned int i = 0; i < records.length; i++)
	  c->serializer->pop_discard ();
	return_trace (false);
      }
    }

    /* Workaround to ensure offset ordering is from least to greatest when
     * resolving links. */
    hb_vector_t<hb_serialize_context_t::objidx_t> objidxs;
    for (unsigned int i = 0; i < records.length; i++)
      objidxs.push (c->serializer->pop_pack ());
    for (unsigned int i = 0; i < records.length; i++)
    {
      IndexSubtableRecord* record = c->serializer->embed (records[i]);
      if (unlikely (!record)) return_trace (false);
      c->serializer->add_link (record->offsetToSubtable, objidxs[records.length - 1 - i]);
    }
    return_trace (true);
  }

  public:
  const IndexSubtableRecord* find_table (hb_codepoint_t glyph, unsigned int numTables) const
  {
    for (unsigned int i = 0; i < numTables; ++i)
    {
      unsigned int firstGlyphIndex = indexSubtablesZ[i].firstGlyphIndex;
      unsigned int lastGlyphIndex = indexSubtablesZ[i].lastGlyphIndex;
      if (firstGlyphIndex <= glyph && glyph <= lastGlyphIndex)
	return &indexSubtablesZ[i];
    }
    return nullptr;
  }

  protected:
  UnsizedArrayOf<IndexSubtableRecord>	indexSubtablesZ;
};

struct BitmapSizeTable
{
  friend struct CBLC;
  friend struct CBDT;

  bool sanitize (hb_sanitize_context_t *c, const void *base) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  indexSubtableArrayOffset.sanitize (c, base, numberOfIndexSubtables) &&
		  horizontal.sanitize (c) &&
		  vertical.sanitize (c));
  }

  const IndexSubtableRecord *
  find_table (hb_codepoint_t glyph, const void *base, const void **out_base) const
  {
    *out_base = &(base+indexSubtableArrayOffset);
    return (base+indexSubtableArrayOffset).find_table (glyph, numberOfIndexSubtables);
  }

  bool
  subset (hb_subset_context_t *c, const void *base,
	  const char *cbdt, unsigned int cbdt_length,
	  hb_vector_t<char> *cbdt_prime /* INOUT */) const
  {
    TRACE_SUBSET (this);
    auto *out_table = c->serializer->embed (this);
    if (unlikely (!out_table)) return_trace (false);

    cblc_bitmap_size_subset_context_t bitmap_size_context;
    bitmap_size_context.cbdt = cbdt;
    bitmap_size_context.cbdt_length = cbdt_length;
    bitmap_size_context.cbdt_prime = cbdt_prime;
    bitmap_size_context.size = indexTablesSize;
    bitmap_size_context.num_tables = numberOfIndexSubtables;
    bitmap_size_context.start_glyph = 1;
    bitmap_size_context.end_glyph = 0;

    if (!out_table->indexSubtableArrayOffset.serialize_subset (c,
							       indexSubtableArrayOffset,
							       base,
							       &bitmap_size_context))
      return_trace (false);
    if (!bitmap_size_context.size ||
	!bitmap_size_context.num_tables ||
	bitmap_size_context.start_glyph > bitmap_size_context.end_glyph)
      return_trace (false);

    out_table->indexTablesSize = bitmap_size_context.size;
    out_table->numberOfIndexSubtables = bitmap_size_context.num_tables;
    out_table->startGlyphIndex = bitmap_size_context.start_glyph;
    out_table->endGlyphIndex = bitmap_size_context.end_glyph;
    return_trace (true);
  }

  protected:
  LNNOffsetTo<IndexSubtableArray>
			indexSubtableArrayOffset;
  HBUINT32		indexTablesSize;
  HBUINT32		numberOfIndexSubtables;
  HBUINT32		colorRef;
  SBitLineMetrics	horizontal;
  SBitLineMetrics	vertical;
  HBGlyphID		startGlyphIndex;
  HBGlyphID		endGlyphIndex;
  HBUINT8		ppemX;
  HBUINT8		ppemY;
  HBUINT8		bitDepth;
  HBINT8		flags;
  public:
  DEFINE_SIZE_STATIC (48);
};

/*
 * Glyph Bitmap Data Formats.
 */

struct GlyphBitmapDataFormat17
{
  SmallGlyphMetrics	glyphMetrics;
  LArrayOf<HBUINT8>	data;
  public:
  DEFINE_SIZE_ARRAY (9, data);
};

struct GlyphBitmapDataFormat18
{
  BigGlyphMetrics	glyphMetrics;
  LArrayOf<HBUINT8>	data;
  public:
  DEFINE_SIZE_ARRAY (12, data);
};

struct GlyphBitmapDataFormat19
{
  LArrayOf<HBUINT8>	data;
  public:
  DEFINE_SIZE_ARRAY (4, data);
};

struct CBLC
{
  friend struct CBDT;

  static constexpr hb_tag_t tableTag = HB_OT_TAG_CBLC;

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  likely (version.major == 2 || version.major == 3) &&
		  sizeTables.sanitize (c, this));
  }

  static bool
  sink_cbdt (hb_subset_context_t *c, hb_vector_t<char>* cbdt_prime)
  {
    hb_blob_t *cbdt_prime_blob = hb_blob_create (cbdt_prime->arrayZ,
						 cbdt_prime->length,
						 HB_MEMORY_MODE_WRITABLE,
						 cbdt_prime->arrayZ,
						 free);
    cbdt_prime->init ();  // Leak arrayZ to the blob.
    bool ret = c->plan->add_table (HB_OT_TAG_CBDT, cbdt_prime_blob);
    hb_blob_destroy (cbdt_prime_blob);
    return ret;
  }

  bool
  subset_size_table (hb_subset_context_t *c, const BitmapSizeTable& table,
		     const char *cbdt /* IN */, unsigned int cbdt_length,
		     CBLC *cblc_prime /* INOUT */, hb_vector_t<char> *cbdt_prime /* INOUT */) const
  {
    TRACE_SUBSET (this);
    cblc_prime->sizeTables.len++;

    auto snap = c->serializer->snapshot ();
    auto cbdt_prime_len = cbdt_prime->length;

    if (!table.subset (c, this, cbdt, cbdt_length, cbdt_prime))
    {
      cblc_prime->sizeTables.len--;
      c->serializer->revert (snap);
      cbdt_prime->shrink (cbdt_prime_len);
      return_trace (false);
    }
    return_trace (true);
  }

  // Implemented in cc file as it depends on definition of CBDT.
  HB_INTERNAL bool subset (hb_subset_context_t *c) const;

  protected:
  const BitmapSizeTable &choose_strike (hb_font_t *font) const
  {
    unsigned count = sizeTables.len;
    if (unlikely (!count))
      return Null (BitmapSizeTable);

    unsigned int requested_ppem = hb_max (font->x_ppem, font->y_ppem);
    if (!requested_ppem)
      requested_ppem = 1<<30; /* Choose largest strike. */
    unsigned int best_i = 0;
    unsigned int best_ppem = hb_max (sizeTables[0].ppemX, sizeTables[0].ppemY);

    for (unsigned int i = 1; i < count; i++)
    {
      unsigned int ppem = hb_max (sizeTables[i].ppemX, sizeTables[i].ppemY);
      if ((requested_ppem <= ppem && ppem < best_ppem) ||
	  (requested_ppem > best_ppem && ppem > best_ppem))
      {
	best_i = i;
	best_ppem = ppem;
      }
    }

    return sizeTables[best_i];
  }

  protected:
  FixedVersion<>		version;
  LArrayOf<BitmapSizeTable>	sizeTables;
  public:
  DEFINE_SIZE_ARRAY (8, sizeTables);
};

struct CBDT
{
  static constexpr hb_tag_t tableTag = HB_OT_TAG_CBDT;

  struct accelerator_t
  {
    void init (hb_face_t *face)
    {
      cblc = hb_sanitize_context_t ().reference_table<CBLC> (face);
      cbdt = hb_sanitize_context_t ().reference_table<CBDT> (face);

      upem = hb_face_get_upem (face);
    }

    void fini ()
    {
      this->cblc.destroy ();
      this->cbdt.destroy ();
    }

    bool
    get_extents (hb_font_t *font, hb_codepoint_t glyph, hb_glyph_extents_t *extents) const
    {
      const void *base;
      const BitmapSizeTable &strike = this->cblc->choose_strike (font);
      const IndexSubtableRecord *subtable_record = strike.find_table (glyph, cblc, &base);
      if (!subtable_record || !strike.ppemX || !strike.ppemY)
	return false;

      if (subtable_record->get_extents (extents, base))
	return true;

      unsigned int image_offset = 0, image_length = 0, image_format = 0;
      if (!subtable_record->get_image_data (glyph, base, &image_offset, &image_length, &image_format))
	return false;

      unsigned int cbdt_len = cbdt.get_length ();
      if (unlikely (image_offset > cbdt_len || cbdt_len - image_offset < image_length))
	return false;

      switch (image_format)
      {
      case 17: {
	if (unlikely (image_length < GlyphBitmapDataFormat17::min_size))
	  return false;
	auto &glyphFormat17 = StructAtOffset<GlyphBitmapDataFormat17> (this->cbdt, image_offset);
	glyphFormat17.glyphMetrics.get_extents (font, extents);
	break;
      }
      case 18: {
	if (unlikely (image_length < GlyphBitmapDataFormat18::min_size))
	  return false;
	auto &glyphFormat18 = StructAtOffset<GlyphBitmapDataFormat18> (this->cbdt, image_offset);
	glyphFormat18.glyphMetrics.get_extents (font, extents);
	break;
      }
      default: return false; /* TODO: Support other image formats. */
      }

      /* Convert to font units. */
      float x_scale = upem / (float) strike.ppemX;
      float y_scale = upem / (float) strike.ppemY;
      extents->x_bearing = roundf (extents->x_bearing * x_scale);
      extents->y_bearing = roundf (extents->y_bearing * y_scale);
      extents->width = roundf (extents->width * x_scale);
      extents->height = roundf (extents->height * y_scale);

      return true;
    }

    hb_blob_t*
    reference_png (hb_font_t *font, hb_codepoint_t glyph) const
    {
      const void *base;
      const BitmapSizeTable &strike = this->cblc->choose_strike (font);
      const IndexSubtableRecord *subtable_record = strike.find_table (glyph, cblc, &base);
      if (!subtable_record || !strike.ppemX || !strike.ppemY)
	return hb_blob_get_empty ();

      unsigned int image_offset = 0, image_length = 0, image_format = 0;
      if (!subtable_record->get_image_data (glyph, base, &image_offset, &image_length, &image_format))
	return hb_blob_get_empty ();

      unsigned int cbdt_len = cbdt.get_length ();
      if (unlikely (image_offset > cbdt_len || cbdt_len - image_offset < image_length))
	return hb_blob_get_empty ();

      switch (image_format)
      {
      case 17:
      {
	if (unlikely (image_length < GlyphBitmapDataFormat17::min_size))
	  return hb_blob_get_empty ();
	auto &glyphFormat17 = StructAtOffset<GlyphBitmapDataFormat17> (this->cbdt, image_offset);
	return hb_blob_create_sub_blob (cbdt.get_blob (),
					image_offset + GlyphBitmapDataFormat17::min_size,
					glyphFormat17.data.len);
      }
      case 18:
      {
	if (unlikely (image_length < GlyphBitmapDataFormat18::min_size))
	  return hb_blob_get_empty ();
	auto &glyphFormat18 = StructAtOffset<GlyphBitmapDataFormat18> (this->cbdt, image_offset);
	return hb_blob_create_sub_blob (cbdt.get_blob (),
					image_offset + GlyphBitmapDataFormat18::min_size,
					glyphFormat18.data.len);
      }
      case 19:
      {
	if (unlikely (image_length < GlyphBitmapDataFormat19::min_size))
	  return hb_blob_get_empty ();
	auto &glyphFormat19 = StructAtOffset<GlyphBitmapDataFormat19> (this->cbdt, image_offset);
	return hb_blob_create_sub_blob (cbdt.get_blob (),
					image_offset + GlyphBitmapDataFormat19::min_size,
					glyphFormat19.data.len);
      }
      default: return hb_blob_get_empty (); /* TODO: Support other image formats. */
      }
    }

    bool has_data () const { return cbdt.get_length (); }

    private:
    hb_blob_ptr_t<CBLC> cblc;
    hb_blob_ptr_t<CBDT> cbdt;

    unsigned int upem;
  };

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  likely (version.major == 2 || version.major == 3));
  }

  protected:
  FixedVersion<>		version;
  UnsizedArrayOf<HBUINT8>	dataZ;
  public:
  DEFINE_SIZE_ARRAY (4, dataZ);
};

inline bool
CBLC::subset (hb_subset_context_t *c) const
{
  TRACE_SUBSET (this);

  auto *cblc_prime = c->serializer->start_embed<CBLC> ();

  // Use a vector as a secondary buffer as the tables need to be built in parallel.
  hb_vector_t<char> cbdt_prime;

  if (unlikely (!cblc_prime)) return_trace (false);
  if (unlikely (!c->serializer->extend_min (cblc_prime))) return_trace (false);
  cblc_prime->version = version;

  hb_blob_t* cbdt_blob = hb_sanitize_context_t ().reference_table<CBDT> (c->plan->source);
  unsigned int cbdt_length;
  CBDT* cbdt = (CBDT *) hb_blob_get_data (cbdt_blob, &cbdt_length);
  if (unlikely (cbdt_length < CBDT::min_size))
  {
    hb_blob_destroy (cbdt_blob);
    return_trace (false);
  }
  _copy_data_to_cbdt (&cbdt_prime, cbdt, CBDT::min_size);

  for (const BitmapSizeTable& table : + sizeTables.iter ())
    subset_size_table (c, table, (const char *) cbdt, cbdt_length, cblc_prime, &cbdt_prime);

  hb_blob_destroy (cbdt_blob);

  return_trace (CBLC::sink_cbdt (c, &cbdt_prime));
}

struct CBDT_accelerator_t : CBDT::accelerator_t {};

} /* namespace OT */

#endif /* HB_OT_COLOR_CBDT_TABLE_HH */


text:
#!/bin/sh

LC_ALL=C
export LC_ALL

test -z "$srcdir" && srcdir=.
test -z "$builddir" && builddir=.
test -z "$libs" && libs=.libs
stat=0

IGNORED_SYMBOLS='_fini\|_init\|_fdata\|_ftext\|_fbss\|__bss_start\|__bss_start__\|__bss_end__\|_edata\|_end\|_bss_end__\|__end__\|__gcov_.*\|llvm_.*\|flush_fn_list\|writeout_fn_list'

if which nm 2>/dev/null >/dev/null; then
	:
else
	echo "check-symbols.sh: 'nm' not found; skipping test"
	exit 77
fi

tested=false
for soname in harfbuzz harfbuzz-subset harfbuzz-icu harfbuzz-gobject; do
	for suffix in so dylib; do
		so=$libs/lib$soname.$suffix
		if ! test -f "$so"; then continue; fi

		# On macOS, C symbols are prefixed with _
		symprefix=
		if test $suffix = dylib; then symprefix=_; fi

		EXPORTED_SYMBOLS=`nm "$so" | grep ' [BCDGIRST] .' | grep -v " $symprefix\\($IGNORED_SYMBOLS\\>\\)" | cut -d' ' -f3 | c++filt`

		prefix=$symprefix`basename "$so" | sed 's/libharfbuzz/hb/; s/-/_/g; s/[.].*//'`

		echo "Checking that $so does not expose internal symbols"
		if echo "$EXPORTED_SYMBOLS" | grep -v "^${prefix}\(_\|$\)"; then
			echo "Ouch, internal symbols exposed"
			stat=1
		fi

		def=$builddir/$soname.def
		if ! test -f "$def"; then
			echo "'$def' not found; skipping"
		else
			echo "Checking that $so has the same symbol list as $def"
			{
				echo EXPORTS
				echo "$EXPORTED_SYMBOLS" | sed -e "s/^${symprefix}hb/hb/g"
				# cheat: copy the last line from the def file!
				tail -n1 "$def"
			} | c++filt | diff "$def" - >&2 || stat=1

			tested=true
		fi
	done
done
if ! $tested; then
	echo "check-symbols.sh: no shared libraries found; skipping test"
	exit 77
fi

exit $stat