booster.rb in lightgbm-0.1.6

- old
+ new

@@ -38,11 +38,11 @@
       num_iteration ||= best_iteration
       buffer_len = 1 << 20
       out_len = ::FFI::MemoryPointer.new(:int64)
       out_str = ::FFI::MemoryPointer.new(:string, buffer_len)
       check_result FFI.LGBM_BoosterDumpModel(handle_pointer, start_iteration, num_iteration, buffer_len, out_len, out_str)
-      actual_len = out_len.read_int64
+      actual_len = read_int64(out_len)
       if actual_len > buffer_len
         out_str = ::FFI::MemoryPointer.new(:string, actual_len)
         check_result FFI.LGBM_BoosterDumpModel(handle_pointer, start_iteration, num_iteration, actual_len, out_len, out_str)
       end
       out_str.read_string
@@ -85,11 +85,11 @@
       num_iteration ||= best_iteration
       buffer_len = 1 << 20
       out_len = ::FFI::MemoryPointer.new(:int64)
       out_str = ::FFI::MemoryPointer.new(:string, buffer_len)
       check_result FFI.LGBM_BoosterSaveModelToString(handle_pointer, start_iteration, num_iteration, buffer_len, out_len, out_str)
-      actual_len = out_len.read_int64
+      actual_len = read_int64(out_len)
       if actual_len > buffer_len
         out_str = ::FFI::MemoryPointer.new(:string, actual_len)
         check_result FFI.LGBM_BoosterSaveModelToString(handle_pointer, start_iteration, num_iteration, actual_len, out_len, out_str)
       end
       out_str.read_string
@@ -135,11 +135,11 @@
       data.put_array_of_float(0, flat_input)
 
       out_len = ::FFI::MemoryPointer.new(:int64)
       out_result = ::FFI::MemoryPointer.new(:double, num_class * input.count)
       check_result FFI.LGBM_BoosterPredictForMat(handle_pointer, data, 0, input.count, input.first.count, 1, 0, num_iteration, params_str(params), out_len, out_result)
-      out = out_result.read_array_of_double(out_len.read_int64)
+      out = out_result.read_array_of_double(read_int64(out_len))
       out = out.each_slice(num_class).to_a if num_class > 1
 
       singular ? out.first : out
     end
 
@@ -198,9 +198,14 @@
 
     def num_class
       out = ::FFI::MemoryPointer.new(:int)
       check_result FFI::LGBM_BoosterGetNumClasses(handle_pointer, out)
       out.read_int
+    end
+
+    # read_int64 not available on JRuby
+    def read_int64(ptr)
+      ptr.read_array_of_int64(1).first
     end
 
     include Utils
   end
 end