#ifndef OT_LAYOUT_GSUB_ALTERNATESET_HH

#define OT_LAYOUT_GSUB_ALTERNATESET_HH

#include "Common.hh"

namespace OT {

namespace Layout {

namespace GSUB_impl {

template <typename Types>

struct AlternateSet

{

  protected:

  Array16Of<typename Types::HBGlyphID>

                alternates;             /* Array of alternate GlyphIDs--in

                                         * arbitrary order */

  public:

  DEFINE_SIZE_ARRAY (2, alternates);

  bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    return_trace (alternates.sanitize (c));

  }

  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)

    {

      /* Maybe we can do better than unsafe-to-break all; but since we are

       * changing random state, it would be hard to track that.  Good 'nough. */

      c->buffer->unsafe_to_break (0, c->buffer->len);

      alt_index = c->random_number () % count + 1;

    }

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

    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())

    {

      c->buffer->sync_so_far ();

      c->buffer->message (c->font,

        "replacing glyph at %u (alternate substitution)",

        c->buffer->idx);

    }

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

    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())

    {

      c->buffer->message (c->font,

        "replaced glyph at %u (alternate substitution)",

        c->buffer->idx - 1u);

    }

    return_trace (true);

  }

  unsigned

  get_alternates (unsigned        start_offset,

                  unsigned       *alternate_count  /* IN/OUT.  May be NULL. */,

                  hb_codepoint_t *alternate_glyphs /* OUT.     May be NULL. */) const

  {

    if (alternates.len && alternate_count)

    {

      + alternates.as_array ().sub_array (start_offset, alternate_count)

      | hb_sink (hb_array (alternate_glyphs, *alternate_count))

      ;

    }

    return alternates.len;

  }

  void

  collect_alternates (hb_codepoint_t gid,

          hb_map_t  *alternate_count /* IN/OUT */,

          hb_map_t  *alternate_glyphs /* IN/OUT */) const

  {

    + hb_enumerate (alternates)

    | hb_map ([gid] (hb_pair_t<unsigned, hb_codepoint_t> _) { return hb_pair (gid + (_.first << 24), _.second); })

    | hb_apply ([&] (const hb_pair_t<hb_codepoint_t, hb_codepoint_t> &p) -> void

    { _hb_collect_glyph_alternates_add (p.first, p.second,

                alternate_count, alternate_glyphs); })

    ;

  }

  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));

  }

Unexecuted instantiation: _ZN2OT6Layout9GSUB_impl12AlternateSetINS0_10SmallTypesEE9serializeI10hb_array_tIKNS_11HBGlyphID16EETnPN12hb_enable_ifIXsr15hb_is_source_ofIT_jEE5valueEvE4typeELPv0EEEbP22hb_serialize_context_tSB_

Unexecuted instantiation: hb-ot-face.cc:_ZN2OT6Layout9GSUB_impl12AlternateSetINS0_10SmallTypesEE9serializeI13hb_map_iter_tI16hb_filter_iter_tI10hb_array_tIKNS_11HBGlyphID16EERK8hb_set_tRK4$_19LPv0EERK8hb_map_tL24hb_function_sortedness_t0ELSI_0EETnPN12hb_enable_ifIXsr15hb_is_source_ofIT_jEE5valueEvE4typeELSI_0EEEbP22hb_serialize_context_tSQ_

Unexecuted instantiation: hb-aat-layout.cc:_ZN2OT6Layout9GSUB_impl12AlternateSetINS0_10SmallTypesEE9serializeI13hb_map_iter_tI16hb_filter_iter_tI10hb_array_tIKNS_11HBGlyphID16EERK8hb_set_tRK4$_19LPv0EERK8hb_map_tL24hb_function_sortedness_t0ELSI_0EETnPN12hb_enable_ifIXsr15hb_is_source_ofIT_jEE5valueEvE4typeELSI_0EEEbP22hb_serialize_context_tSQ_

Unexecuted instantiation: hb-ot-layout.cc:_ZN2OT6Layout9GSUB_impl12AlternateSetINS0_10SmallTypesEE9serializeI13hb_map_iter_tI16hb_filter_iter_tI10hb_array_tIKNS_11HBGlyphID16EERK8hb_set_tRK4$_19LPv0EERK8hb_map_tL24hb_function_sortedness_t0ELSI_0EETnPN12hb_enable_ifIXsr15hb_is_source_ofIT_jEE5valueEvE4typeELSI_0EEEbP22hb_serialize_context_tSQ_

Unexecuted instantiation: hb-ot-shaper-arabic.cc:_ZN2OT6Layout9GSUB_impl12AlternateSetINS0_10SmallTypesEE9serializeI13hb_map_iter_tI16hb_filter_iter_tI10hb_array_tIKNS_11HBGlyphID16EERK8hb_set_tRK4$_19LPv0EERK8hb_map_tL24hb_function_sortedness_t0ELSI_0EETnPN12hb_enable_ifIXsr15hb_is_source_ofIT_jEE5valueEvE4typeELSI_0EEEbP22hb_serialize_context_tSQ_

  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_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);

  }

};

}

}

}

#endif /* OT_LAYOUT_GSUB_ALTERNATESET_HH */