1 files changed, 281 insertions, 0 deletions
diff --git a/thirdparty/harfbuzz/src/OT/Layout/GPOS/CursivePosFormat1.hh b/thirdparty/harfbuzz/src/OT/Layout/GPOS/CursivePosFormat1.hh
new file mode 100644
index 0000000000..e212fab976
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/Layout/GPOS/CursivePosFormat1.hh
@@ -0,0 +1,281 @@
+#ifndef OT_LAYOUT_GPOS_CURSIVEPOSFORMAT1_HH
+#define OT_LAYOUT_GPOS_CURSIVEPOSFORMAT1_HH
+
+#include "Anchor.hh"
+
+namespace OT {
+namespace Layout {
+namespace GPOS_impl {
+
+struct EntryExitRecord
+{
+  friend struct CursivePosFormat1;
+
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (entryAnchor.sanitize (c, base) && exitAnchor.sanitize (c, base));
+  }
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c,
+                                  const void *src_base) const
+  {
+    (src_base+entryAnchor).collect_variation_indices (c);
+    (src_base+exitAnchor).collect_variation_indices (c);
+  }
+
+  EntryExitRecord* subset (hb_subset_context_t *c,
+                           const void *src_base) const
+  {
+    TRACE_SERIALIZE (this);
+    auto *out = c->serializer->embed (this);
+    if (unlikely (!out)) return_trace (nullptr);
+
+    out->entryAnchor.serialize_subset (c, entryAnchor, src_base);
+    out->exitAnchor.serialize_subset (c, exitAnchor, src_base);
+    return_trace (out);
+  }
+
+  protected:
+  Offset16To<Anchor>
+                entryAnchor;            /* Offset to EntryAnchor table--from
+                                         * beginning of CursivePos
+                                         * subtable--may be NULL */
+  Offset16To<Anchor>
+                exitAnchor;             /* Offset to ExitAnchor table--from
+                                         * beginning of CursivePos
+                                         * subtable--may be NULL */
+  public:
+  DEFINE_SIZE_STATIC (4);
+};
+
+static void
+reverse_cursive_minor_offset (hb_glyph_position_t *pos, unsigned int i, hb_direction_t direction, unsigned int new_parent) {
+  int chain = pos[i].attach_chain(), type = pos[i].attach_type();
+  if (likely (!chain || 0 == (type & ATTACH_TYPE_CURSIVE)))
+    return;
+
+  pos[i].attach_chain() = 0;
+
+  unsigned int j = (int) i + chain;
+
+  /* Stop if we see new parent in the chain. */
+  if (j == new_parent)
+    return;
+
+  reverse_cursive_minor_offset (pos, j, direction, new_parent);
+
+  if (HB_DIRECTION_IS_HORIZONTAL (direction))
+    pos[j].y_offset = -pos[i].y_offset;
+  else
+    pos[j].x_offset = -pos[i].x_offset;
+
+  pos[j].attach_chain() = -chain;
+  pos[j].attach_type() = type;
+}
+
+
+struct CursivePosFormat1
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  Offset16To<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of subtable */
+  Array16Of<EntryExitRecord>
+                entryExitRecord;        /* Array of EntryExit records--in
+                                         * Coverage Index order */
+  public:
+  DEFINE_SIZE_ARRAY (6, entryExitRecord);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (coverage.sanitize (c, this) && entryExitRecord.sanitize (c, this));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return (this+coverage).intersects (glyphs); }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
+  {
+    + hb_zip (this+coverage, entryExitRecord)
+    | hb_filter (c->glyph_set, hb_first)
+    | hb_map (hb_second)
+    | hb_apply ([&] (const EntryExitRecord& record) { record.collect_variation_indices (c, this); })
+    ;
+  }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  { if (unlikely (!(this+coverage).collect_coverage (c->input))) return; }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    hb_buffer_t *buffer = c->buffer;
+
+    const EntryExitRecord &this_record = entryExitRecord[(this+coverage).get_coverage  (buffer->cur().codepoint)];
+    if (!this_record.entryAnchor) return_trace (false);
+
+    hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
+    skippy_iter.reset (buffer->idx, 1);
+    unsigned unsafe_from;
+    if (!skippy_iter.prev (&unsafe_from))
+    {
+      buffer->unsafe_to_concat_from_outbuffer (unsafe_from, buffer->idx + 1);
+      return_trace (false);
+    }
+
+    const EntryExitRecord &prev_record = entryExitRecord[(this+coverage).get_coverage  (buffer->info[skippy_iter.idx].codepoint)];
+    if (!prev_record.exitAnchor)
+    {
+      buffer->unsafe_to_concat_from_outbuffer (skippy_iter.idx, buffer->idx + 1);
+      return_trace (false);
+    }
+
+    unsigned int i = skippy_iter.idx;
+    unsigned int j = buffer->idx;
+
+    buffer->unsafe_to_break (i, j);
+    float entry_x, entry_y, exit_x, exit_y;
+    (this+prev_record.exitAnchor).get_anchor (c, buffer->info[i].codepoint, &exit_x, &exit_y);
+    (this+this_record.entryAnchor).get_anchor (c, buffer->info[j].codepoint, &entry_x, &entry_y);
+
+    hb_glyph_position_t *pos = buffer->pos;
+
+    hb_position_t d;
+    /* Main-direction adjustment */
+    switch (c->direction) {
+      case HB_DIRECTION_LTR:
+        pos[i].x_advance  = roundf (exit_x) + pos[i].x_offset;
+
+        d = roundf (entry_x) + pos[j].x_offset;
+        pos[j].x_advance -= d;
+        pos[j].x_offset  -= d;
+        break;
+      case HB_DIRECTION_RTL:
+        d = roundf (exit_x) + pos[i].x_offset;
+        pos[i].x_advance -= d;
+        pos[i].x_offset  -= d;
+
+        pos[j].x_advance  = roundf (entry_x) + pos[j].x_offset;
+        break;
+      case HB_DIRECTION_TTB:
+        pos[i].y_advance  = roundf (exit_y) + pos[i].y_offset;
+
+        d = roundf (entry_y) + pos[j].y_offset;
+        pos[j].y_advance -= d;
+        pos[j].y_offset  -= d;
+        break;
+      case HB_DIRECTION_BTT:
+        d = roundf (exit_y) + pos[i].y_offset;
+        pos[i].y_advance -= d;
+        pos[i].y_offset  -= d;
+
+        pos[j].y_advance  = roundf (entry_y);
+        break;
+      case HB_DIRECTION_INVALID:
+      default:
+        break;
+    }
+
+    /* Cross-direction adjustment */
+
+    /* We attach child to parent (think graph theory and rooted trees whereas
+     * the root stays on baseline and each node aligns itself against its
+     * parent.
+     *
+     * Optimize things for the case of RightToLeft, as that's most common in
+     * Arabic. */
+    unsigned int child  = i;
+    unsigned int parent = j;
+    hb_position_t x_offset = entry_x - exit_x;
+    hb_position_t y_offset = entry_y - exit_y;
+    if  (!(c->lookup_props & LookupFlag::RightToLeft))
+    {
+      unsigned int k = child;
+      child = parent;
+      parent = k;
+      x_offset = -x_offset;
+      y_offset = -y_offset;
+    }
+
+    /* If child was already connected to someone else, walk through its old
+     * chain and reverse the link direction, such that the whole tree of its
+     * previous connection now attaches to new parent.  Watch out for case
+     * where new parent is on the path from old chain...
+     */
+    reverse_cursive_minor_offset (pos, child, c->direction, parent);
+
+    pos[child].attach_type() = ATTACH_TYPE_CURSIVE;
+    pos[child].attach_chain() = (int) parent - (int) child;
+    buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
+    if (likely (HB_DIRECTION_IS_HORIZONTAL (c->direction)))
+      pos[child].y_offset = y_offset;
+    else
+      pos[child].x_offset = x_offset;
+
+    /* If parent was attached to child, separate them.
+     * https://github.com/harfbuzz/harfbuzz/issues/2469
+     */
+    if (unlikely (pos[parent].attach_chain() == -pos[child].attach_chain()))
+      pos[parent].attach_chain() = 0;
+
+    buffer->idx++;
+    return_trace (true);
+  }
+
+  template <typename Iterator,
+            hb_requires (hb_is_iterator (Iterator))>
+  void serialize (hb_subset_context_t *c,
+                  Iterator it,
+                  const void *src_base)
+  {
+    if (unlikely (!c->serializer->extend_min ((*this)))) return;
+    this->format = 1;
+    this->entryExitRecord.len = it.len ();
+
+    for (const EntryExitRecord& entry_record : + it
+                                               | hb_map (hb_second))
+      entry_record.subset (c, src_base);
+
+    auto glyphs =
+    + it
+    | hb_map_retains_sorting (hb_first)
+    ;
+
+    coverage.serialize_serialize (c->serializer, glyphs);
+  }
+
+  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 *out = c->serializer->start_embed (*this);
+    if (unlikely (!out)) return_trace (false);
+
+    auto it =
+    + hb_zip (this+coverage, entryExitRecord)
+    | hb_filter (glyphset, hb_first)
+    | hb_map_retains_sorting ([&] (hb_pair_t<hb_codepoint_t, const EntryExitRecord&> p) -> hb_pair_t<hb_codepoint_t, const EntryExitRecord&>
+                              { return hb_pair (glyph_map[p.first], p.second);})
+    ;
+
+    bool ret = bool (it);
+    out->serialize (c, it, this);
+    return_trace (ret);
+  }
+};
+
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GPOS_CURSIVEPOSFORMAT1_HH */