#ifndef OT_GLYF_SUBSETGLYPH_HH

#define OT_GLYF_SUBSETGLYPH_HH

#include "../../hb-open-type.hh"

namespace OT {

struct glyf_accelerator_t;

namespace glyf_impl {

struct SubsetGlyph

{

  hb_codepoint_t old_gid;

  Glyph source_glyph;

  hb_bytes_t dest_start;  /* region of source_glyph to copy first */

  hb_bytes_t dest_end;    /* region of source_glyph to copy second */

  bool allocated;

  bool serialize (hb_serialize_context_t *c,

      bool use_short_loca,

      const hb_subset_plan_t *plan) const

  {

    TRACE_SERIALIZE (this);

    hb_bytes_t dest_glyph = dest_start.copy (c);

    hb_bytes_t end_copy = dest_end.copy (c);

    if (!end_copy.arrayZ || !dest_glyph.arrayZ) {

      return false;

    }

    dest_glyph = hb_bytes_t (&dest_glyph, dest_glyph.length + end_copy.length);

    unsigned int pad_length = use_short_loca ? padding () : 0;

    DEBUG_MSG (SUBSET, nullptr, "serialize %u byte glyph, width %u pad %u", dest_glyph.length, dest_glyph.length + pad_length, pad_length);

    HBUINT8 pad;

    pad = 0;

    while (pad_length > 0)

    {

      (void) c->embed (pad);

      pad_length--;

    }

    if (unlikely (!dest_glyph.length)) return_trace (true);

    /* update components gids. */

    for (auto &_ : Glyph (dest_glyph).get_composite_iterator ())

    {

      hb_codepoint_t new_gid;

      if (plan->new_gid_for_old_gid (_.get_gid(), &new_gid))

  const_cast<CompositeGlyphRecord &> (_).set_gid (new_gid);

    }

#ifndef HB_NO_BEYOND_64K

    auto it = Glyph (dest_glyph).get_composite_iterator ();

    if (it)

    {

      /* lower GID24 to GID16 in components if possible. */

      char *p = it ? (char *) &*it : nullptr;

      char *q = p;

      const char *end = dest_glyph.arrayZ + dest_glyph.length;

      while (it)

      {

  auto &rec = const_cast<CompositeGlyphRecord &> (*it);

  ++it;

  q += rec.get_size ();

  rec.lower_gid_24_to_16 ();

  unsigned size = rec.get_size ();

  memmove (p, &rec, size);

  p += size;

      }

      memmove (p, q, end - q);

      p += end - q;

      /* We want to shorten the glyph, but we can't do that without

       * updating the length in the loca table, which is already

       * written out :-(.  So we just fill the rest of the glyph with

       * harmless instructions, since that's what they will be

       * interpreted as.

       *

       * Should move the lowering to _populate_subset_glyphs() to

       * fix this issue. */

      hb_memset (p, 0x7A /* TrueType instruction ROFF; harmless */, end - p);

      p += end - p;

      dest_glyph = hb_bytes_t (dest_glyph.arrayZ, p - (char *) dest_glyph.arrayZ);

      // TODO: Padding; & trim serialized bytes.

      // TODO: Update length in loca. Ugh.

    }

#endif

    if (plan->flags & HB_SUBSET_FLAGS_NO_HINTING)

      Glyph (dest_glyph).drop_hints ();

    if (plan->flags & HB_SUBSET_FLAGS_SET_OVERLAPS_FLAG)

      Glyph (dest_glyph).set_overlaps_flag ();

    return_trace (true);

  }

  bool compile_bytes_with_deltas (const hb_subset_plan_t *plan,

                                  hb_font_t *font,

                                  const glyf_accelerator_t &glyf)

  {

    allocated = source_glyph.compile_bytes_with_deltas (plan, font, glyf, dest_start, dest_end);

    return allocated;

  }

  void free_compiled_bytes ()

  {

    if (likely (allocated)) {

      allocated = false;

      dest_start.fini ();

      dest_end.fini ();

    }

  }

  void drop_hints_bytes ()

  { source_glyph.drop_hints_bytes (dest_start, dest_end); }

  unsigned int      length () const { return dest_start.length + dest_end.length; }

  /* pad to 2 to ensure 2-byte loca will be ok */

  unsigned int     padding () const { return length () % 2; }

  unsigned int padded_size () const { return length () + padding (); }

};

} /* namespace glyf_impl */

} /* namespace OT */

#endif /* OT_GLYF_SUBSETGLYPH_HH */