Improved code

Author: ankane

lib/xgboost/utils.rb

@@ -23,11 +23,9 @@ def string_pointer(value)
     end
 
     def from_cstr_to_rbstr(data, length)
-      res = []
-      length.read_uint64.times do |i|
-        res << data.read_pointer.get_pointer(i * ::FFI::Pointer.size).read_string.force_encoding(Encoding::UTF_8)
+      data.read_pointer.read_array_of_pointer(length.read_uint64).map do |ptr|
+        ptr.read_string.force_encoding(Encoding::UTF_8)
       end
-      res
     end
   end
 end