Merge pull request #2476 from ebraminio/cv-get-chars

[layout] Use dagger in hb_ot_layout_feature_get_characters

src/hb-ot-layout-common.hh

@@ -805,11 +805,16 @@ struct FeatureParamsStylisticSet
 /* https://docs.microsoft.com/en-us/typography/opentype/spec/features_ae#cv01-cv99 */
 struct FeatureParamsCharacterVariants
 {
-  bool sanitize (hb_sanitize_context_t *c) const
+  unsigned
+  get_characters (unsigned start_offset, unsigned *char_count, hb_codepoint_t *chars) const
   {
-    TRACE_SANITIZE (this);
-    return_trace (c->check_struct (this) &&
-		  characters.sanitize (c));
+    if (char_count)
+    {
+      + characters.sub_array (start_offset, char_count)
+      | hb_sink (hb_array (chars, *char_count))
+      ;
+    }
+    return characters.len;
   }
 
   unsigned get_size () const
@@ -821,6 +826,13 @@ struct FeatureParamsCharacterVariants
     return_trace ((bool) c->serializer->embed (*this));
   }
 
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+		  characters.sanitize (c));
+  }
+
   HBUINT16	format;			/* Format number is set to 0. */
   NameID	featUILableNameID;	/* The ‘name’ table name ID that
 					 * specifies a string (or strings,

src/hb-ot-layout.cc

@@ -1710,12 +1710,6 @@ hb_ot_layout_feature_get_name_ids (hb_face_t       *face,
  * Fetches a list of the characters defined as having a variant under the specified
  * "Character Variant" ("cvXX") feature tag.
  *
- * <note>Note: If the char_count output value is equal to its input value, then there
- *       is a chance there were more characters defined under the feature tag than were
- *       returned. This function can be called with incrementally larger start_offset
- *       until the char_count output value is lower than its input value, or the size
- *       of the characters array can be increased.</note>
- *
  * Return value: Number of total sample characters in the cvXX feature.
  *
  * Since: 2.0.0
@@ -1729,24 +1723,10 @@ hb_ot_layout_feature_get_characters (hb_face_t      *face,
 				     hb_codepoint_t *characters  /* OUT.     May be NULL */)
 {
   const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
-
-  hb_tag_t feature_tag = g.get_feature_tag (feature_index);
-  const OT::Feature &f = g.get_feature (feature_index);
-
-  const OT::FeatureParams &feature_params = f.get_feature_params ();
-
-  const OT::FeatureParamsCharacterVariants& cv_params =
-    feature_params.get_character_variants_params(feature_tag);
-
-  unsigned int len = 0;
-  if (char_count && characters && start_offset < cv_params.characters.len)
-  {
-    len = hb_min (cv_params.characters.len - start_offset, *char_count);
-    for (unsigned int i = 0; i < len; ++i)
-      characters[i] = cv_params.characters[start_offset + i];
-  }
-  if (char_count) *char_count = len;
-  return cv_params.characters.len;
+  return g.get_feature (feature_index)
+	  .get_feature_params ()
+	  .get_character_variants_params(g.get_feature_tag (feature_index))
+	  .get_characters (start_offset, char_count, characters);
 }
 #endif
 

test/api/test-ot-name.c

@@ -68,6 +68,15 @@ test_ot_layout_feature_get_name_ids_and_characters (void)
   g_assert_cmpint (char_count, ==, 2);
   g_assert_cmpint (characters[0], ==, 10);
   g_assert_cmpint (characters[1], ==, 24030);
+
+  char_count = 100;
+  characters[1] = 1234;
+  all_chars = hb_ot_layout_feature_get_characters (face, HB_OT_TAG_GSUB, feature_index,
+						   1, &char_count, characters);
+  g_assert_cmpint (all_chars, ==, 2);
+  g_assert_cmpint (char_count, ==, 1);
+  g_assert_cmpint (characters[0], ==, 24030);
+  g_assert_cmpint (characters[1], ==, 1234);
 }
 
 static void