active selection

src/arr.c

@@ -10,4 +10,17 @@ unsigned int arr_uint_index_of(UintArray array, unsigned int value) {
   }
 
   return ARRAY_NOT_FOUND;
+}
+
+unsigned int arr_uint_remap_index(UintArray offsets, unsigned int *index) {
+  unsigned int i;
+
+  for (i = offsets.length - 1; i > 0; i--) {
+    if (*index >= offsets.values[i]) {
+      *index -= offsets.values[i];
+      return i;
+    }
+  }
+
+  return 0;
 }