lib/core: Added an optimized `to_hex` function to `FlatText`

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

diff --git a/lib/core/text/flat.nit b/lib/core/text/flat.nit
index c3332d0..b2336e6 100644 (file)
--- a/lib/core/text/flat.nit
+++ b/lib/core/text/flat.nit
@@ -278,6 +278,23 @@ redef class FlatText
        end
 
        redef fun [](index) do return _items.char_at(char_to_byte_index(index))
+
+       # If `self` contains only digits and alpha <= 'f', return the corresponding integer.
+       #
+       #     assert "ff".to_hex == 255
+       redef fun to_hex(pos, ln) do
+               var res = 0
+               if pos == null then pos = 0
+               if ln == null then ln = length - pos
+               pos = char_to_byte_index(pos)
+               var its = _items
+               var max = pos + ln
+               for i in [pos .. max[ do
+                       res <<= 4
+                       res += its[i].ascii.from_hex
+               end
+               return res
+       end
 end
 
 # Immutable strings of characters.