lib/lightgbm/booster.rb in lightgbm-0.2.4 vs lib/lightgbm/booster.rb in lightgbm-0.2.5

@@ -74,10 +74,30 @@
       out_result = ::FFI::MemoryPointer.new(:double, num_feature)
       check_result FFI.LGBM_BoosterFeatureImportance(handle_pointer, iteration, importance_type, out_result)
       out_result.read_array_of_double(num_feature).map(&:to_i)
     end
 
+    def feature_name
+      len = self.num_feature
+      out_len = ::FFI::MemoryPointer.new(:size_t)
+      buffer_len = 255
+      out_buffer_len = ::FFI::MemoryPointer.new(:size_t)
+      out_strs = ::FFI::MemoryPointer.new(:pointer, num_feature)
+      str_ptrs = len.times.map { ::FFI::MemoryPointer.new(:char, buffer_len) }
+      out_strs.write_array_of_pointer(str_ptrs)
+      check_result FFI.LGBM_BoosterGetFeatureNames(handle_pointer, len, out_len, buffer_len, out_buffer_len, out_strs)
+
+      actual_len = out_buffer_len.read(:size_t)
+      if actual_len > buffer_len
+        str_ptrs = len.times.map { ::FFI::MemoryPointer.new(:char, actual_len) }
+        out_strs.write_array_of_pointer(str_ptrs)
+        check_result FFI.LGBM_BoosterGetFeatureNames(handle_pointer, len, out_len, actual_len, out_buffer_len, out_strs)
+      end
+
+      str_ptrs[0, out_len.read(:size_t)].map(&:read_string)
+    end
+
     def model_from_string(model_str)
       out_num_iterations = ::FFI::MemoryPointer.new(:int)
       check_result FFI.LGBM_BoosterLoadModelFromString(model_str, out_num_iterations, @handle)
       self
     end
@@ -183,9 +203,17 @@
       out_strs = ::FFI::MemoryPointer.new(:pointer, eval_counts)
       buffer_len = 255
       str_ptrs = eval_counts.times.map { ::FFI::MemoryPointer.new(:char, buffer_len) }
       out_strs.write_array_of_pointer(str_ptrs)
       check_result FFI.LGBM_BoosterGetEvalNames(handle_pointer, eval_counts, out_len, buffer_len, out_buffer_len, out_strs)
+
+      actual_len = out_buffer_len.read(:size_t)
+      if actual_len > buffer_len
+        str_ptrs = eval_counts.times.map { ::FFI::MemoryPointer.new(:char, actual_len) }
+        out_strs.write_array_of_pointer(str_ptrs)
+        check_result FFI.LGBM_BoosterGetEvalNames(handle_pointer, eval_counts, out_len, actual_len, out_buffer_len, out_strs)
+      end
+
       str_ptrs.map(&:read_string)
     end
 
     def inner_eval(name, i)
       eval_names ||= eval_names()