lib/string_exp/utf8: Substring now works with UTF-8 strings (pre-indexed).

Signed-off-by: Lucas Bajolet <r4pass@hotmail.com>

diff --git a/lib/string_experimentations/utf8.nit b/lib/string_experimentations/utf8.nit
index eb0737d..629793c 100644 (file)
--- a/lib/string_experimentations/utf8.nit
+++ b/lib/string_experimentations/utf8.nit
@@ -159,6 +159,28 @@ redef class FlatString
                self.bytelen = bytelen
        end
 
+       redef fun substring(from, count)
+       do
+               assert count >= 0
+
+               if from < 0 then
+                       count += from
+                       if count < 0 then count = 0
+                       from = 0
+               end
+
+               if count == 0 then return empty
+
+               var real_from = index_from + from
+               var real_to = real_from + count - 1
+
+               if real_to > index_to then real_to = index_to
+
+               var sub_bytelen = (index[real_to].pos - index[from].pos) + index[from].len
+
+               return new FlatString.with_infos_index(items, count, real_from, real_to, index, sub_bytelen)
+       end
+
        redef fun reversed
        do
                var native = calloc_string(self.bytelen + 1)