Add NativeUtils.powf()

Change-Id: I0339f39d49bc6390d098017f32d92c776974e03e

java/src/com/android/inputmethod/latin/NativeUtils.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+package com.android.inputmethod.latin;
+
+public class NativeUtils {
+    static {
+        JniUtils.loadNativeLibrary();
+    }
+
+    private NativeUtils() {
+        // This utility class is not publicly instantiable.
+    }
+
+    /**
+     * This method just calls up libm's powf() directly.
+     */
+    public static native float powf(float x, float y);
+}

java/src/com/android/inputmethod/latin/UserHistoryForgettingCurveUtils.java

@@ -211,8 +211,8 @@ public class UserHistoryForgettingCurveUtils {
                 }
                 for (int j = 0; j < ELAPSED_TIME_MAX; ++j) {
                     final float elapsedHours = j * ELAPSED_TIME_INTERVAL_HOURS;
-                    final double freq =
-                            initialFreq * Math.pow(initialFreq, elapsedHours / HALF_LIFE_HOURS);
+                    final float freq = initialFreq
+                            * NativeUtils.powf(initialFreq, elapsedHours / HALF_LIFE_HOURS);
                     final int intFreq = Math.min(FC_FREQ_MAX, Math.max(0, (int)freq));
                     SCORE_TABLE[i][j] = intFreq;
                 }

native/jni/Android.mk

@@ -35,6 +35,7 @@ LOCAL_CFLAGS += -Wno-unused-parameter -Wno-unused-function
 LATIN_IME_JNI_SRC_FILES := \
     com_android_inputmethod_keyboard_ProximityInfo.cpp \
     com_android_inputmethod_latin_BinaryDictionary.cpp \
+    com_android_inputmethod_latin_NativeUtils.cpp \
     jni_common.cpp
 
 LATIN_IME_CORE_SRC_FILES := \

native/jni/com_android_inputmethod_latin_NativeUtils.cpp

@@ -0,0 +1,40 @@
+/*
+**
+** Copyright 2012, 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.
+*/
+
+#include "com_android_inputmethod_latin_NativeUtils.h"
+#include "jni.h"
+#include "jni_common.h"
+
+#include <math.h>
+
+namespace latinime {
+
+static float latinime_NativeUtils_powf(float x, float y) {
+    return powf(x, y);
+}
+
+static JNINativeMethod sMethods[] = {
+    {"powf", "(FF)F", (void*)latinime_NativeUtils_powf}
+};
+
+int register_NativeUtils(JNIEnv *env) {
+    const char* const kClassPathName = "com/android/inputmethod/latin/NativeUtils";
+    return registerNativeMethods(env, kClassPathName, sMethods,
+            sizeof(sMethods) / sizeof(sMethods[0]));
+}
+
+} // namespace latinime

native/jni/com_android_inputmethod_latin_NativeUtils.h

@@ -0,0 +1,29 @@
+/*
+**
+** Copyright 2012, 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 _COM_ANDROID_INPUTMETHOD_LATIN_NATIVEUTILS_H
+#define _COM_ANDROID_INPUTMETHOD_LATIN_NATIVEUTILS_H
+
+#include "jni.h"
+
+namespace latinime {
+
+int register_NativeUtils(JNIEnv *env);
+
+}
+
+#endif // _COM_ANDROID_INPUTMETHOD_LATIN_NATIVEUTILS_H

native/jni/jni_common.cpp

@@ -19,6 +19,7 @@
 
 #include "com_android_inputmethod_keyboard_ProximityInfo.h"
 #include "com_android_inputmethod_latin_BinaryDictionary.h"
+#include "com_android_inputmethod_latin_NativeUtils.h"
 #include "defines.h"
 #include "jni.h"
 #include "proximity_info.h"
@@ -52,6 +53,11 @@ jint JNI_OnLoad(JavaVM* vm, void* reserved) {
         goto bail;
     }
 
+    if (!register_NativeUtils(env)) {
+        AKLOGE("ERROR: NativeUtils native registration failed");
+        goto bail;
+    }
+
     /* success -- return valid version number */
     result = JNI_VERSION_1_4;