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diff --git a/native/jni/src/suggest_utils.h b/native/jni/src/suggest_utils.h
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+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_SUGGEST_UTILS_H
+#define LATINIME_SUGGEST_UTILS_H
+
+#include "defines.h"
+#include "proximity_info_state.h"
+
+namespace latinime {
+class SuggestUtils {
+ public:
+    static float getDistanceScalingFactor(const float normalizedSquaredDistance) {
+        if (normalizedSquaredDistance < 0.0f) {
+            return -1.0f;
+        }
+        // Promote or demote the score according to the distance from the sweet spot
+        static const float A = ZERO_DISTANCE_PROMOTION_RATE / 100.0f;
+        static const float B = 1.0f;
+        static const float C = 0.5f;
+        static const float MIN = 0.3f;
+        static const float R1 = NEUTRAL_SCORE_SQUARED_RADIUS;
+        static const float R2 = HALF_SCORE_SQUARED_RADIUS;
+        const float x = normalizedSquaredDistance / static_cast<float>(
+                ProximityInfoState::NORMALIZED_SQUARED_DISTANCE_SCALING_FACTOR);
+        const float factor = max((x < R1)
+                ? (A * (R1 - x) + B * x) / R1
+                : (B * (R2 - x) + C * (x - R1)) / (R2 - R1), MIN);
+        // factor is a piecewise linear function like:
+        // A -_                  .
+        //     ^-_               .
+        // B      \              .
+        //         \_            .
+        // C         ------------.
+        //                       .
+        // 0   R1 R2             .
+        return factor;
+    }
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(SuggestUtils);
+};
+} // namespace latinime
+#endif // LATINIME_SUGGEST_UTILS_H