range fixes

ostd/algorithm.hh

@@ -776,7 +776,9 @@ inline auto foldr_f(T &&init, F &&func) {
 
 template<typename T, typename F, typename R>
 struct map_range: input_range<map_range<T, F, R>> {
-    using range_category  = range_category_t<T>;
+    using range_category  = std::common_type_t<
+        range_category_t<T>, finite_random_access_range_tag
+    >;
     using value_type      = R;
     using reference       = R;
     using size_type       = range_size_t<T>;

ostd/range.hh

@@ -1729,6 +1729,10 @@ struct iterator_range: input_range<iterator_range<T>> {
 
     reference operator[](size_type i) const { return p_beg[i]; }
 
+    /* statisfy contiguous_range */
+    value_type *data() { return p_beg; }
+    value_type const *data() const { return p_beg; }
+
     /* satisfy output_range */
     bool put(value_type const &v) {
         if (empty()) {