[Coverage] Add get_population ()

src/OT/Layout/Common/Coverage.hh

@@ -95,6 +95,19 @@ struct Coverage
     }
   }
 
+  unsigned get_population () const
+  {
+    switch (u.format) {
+    case 1: return u.format1.get_population ();
+    case 2: return u.format2.get_population ();
+#ifndef HB_NO_BORING_EXPANSION
+    case 3: return u.format3.get_population ();
+    case 4: return u.format4.get_population ();
+#endif
+    default:return NOT_COVERED;
+    }
+  }
+
   template <typename Iterator,
       hb_requires (hb_is_sorted_source_of (Iterator, hb_codepoint_t))>
   bool serialize (hb_serialize_context_t *c, Iterator glyphs)

src/OT/Layout/Common/CoverageFormat1.hh

@@ -62,6 +62,11 @@ struct CoverageFormat1_3
     return i;
   }
 
+  unsigned get_population () const
+  {
+    return glyphArray.len;
+  }
+
   template <typename Iterator,
       hb_requires (hb_is_sorted_source_of (Iterator, hb_codepoint_t))>
   bool serialize (hb_serialize_context_t *c, Iterator glyphs)

src/OT/Layout/Common/CoverageFormat2.hh

@@ -65,6 +65,14 @@ struct CoverageFormat2_4
          : NOT_COVERED;
   }
 
+  unsigned get_population () const
+  {
+    unsigned ret = 0;
+    for (const auto &r : rangeRecord)
+      ret += r.get_population (); // TODO Overflow
+    return ret;
+  }
+
   template <typename Iterator,
       hb_requires (hb_is_sorted_source_of (Iterator, hb_codepoint_t))>
   bool serialize (hb_serialize_context_t *c, Iterator glyphs)

src/OT/Layout/Common/RangeRecord.hh

@@ -51,6 +51,12 @@ struct RangeRecord
   int cmp (hb_codepoint_t g) const
   { return g < first ? -1 : g <= last ? 0 : +1; }
 
+  unsigned get_population () const
+  {
+    if (unlikely (last < first)) return 0;
+    return (last - first + 1);
+  }
+
   bool intersects (const hb_set_t *glyphs) const
   { return glyphs->intersects (first, last); }