diff --git a/native/jni/Android.mk b/native/jni/Android.mk
index f5c00f8..7511f4e 100644
--- a/native/jni/Android.mk
+++ b/native/jni/Android.mk
@@ -99,6 +99,7 @@
         ver4_patricia_trie_writing_helper.cpp) \
     $(addprefix suggest/policyimpl/dictionary/structure/v4/content/, \
         bigram_dict_content.cpp \
+        probability_dict_content.cpp \
         shortcut_dict_content.cpp \
         sparse_table_dict_content.cpp \
         terminal_position_lookup_table.cpp) \
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v3/dynamic_patricia_trie_writing_helper.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v3/dynamic_patricia_trie_writing_helper.h
index 4a6b964..e343bf9 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v3/dynamic_patricia_trie_writing_helper.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v3/dynamic_patricia_trie_writing_helper.h
@@ -17,6 +17,7 @@
 #ifndef LATINIME_DYNAMIC_PATRICIA_TRIE_WRITING_HELPER_H
 #define LATINIME_DYNAMIC_PATRICIA_TRIE_WRITING_HELPER_H
 
+#include <cstddef>
 #include <stdint.h>
 
 #include "defines.h"
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/probability_dict_contect.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/probability_dict_contect.cpp
new file mode 100644
index 0000000..eab344e
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/probability_dict_contect.cpp
@@ -0,0 +1,96 @@
+/*
+ * 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.
+ */
+
+#include "suggest/policyimpl/dictionary/structure/v4/content/probability_dict_content.h"
+
+#include "suggest/policyimpl/dictionary/structure/v4/content/single_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h"
+#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
+#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+
+namespace latinime {
+
+int ProbabilityDictContent::getProbability(const int terminalId) const {
+    if (terminalId < 0 || terminalId >= mSize) {
+        return NOT_A_PROBABILITY;
+    }
+    return Ver4PatriciaTrieReadingUtils::getProbability(getBuffer(), terminalId);
+}
+
+bool ProbabilityDictContent::setProbability(const int terminalId, const int probability) {
+    if (terminalId < 0) {
+        return false;
+    }
+    if (terminalId >= mSize) {
+        // Write new entry.
+        int writingPos = getBuffer()->getTailPosition();
+        while (writingPos <= getEntryPos(terminalId)) {
+            const int dummyFlags = 0;
+            if (!getWritableBuffer()->writeUintAndAdvancePosition(dummyFlags,
+                    Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE, &writingPos)) {
+                return false;
+            }
+            const int dummyProbability = 0;
+            if (!getWritableBuffer()->writeUintAndAdvancePosition(dummyProbability,
+                    Ver4DictConstants::PROBABILITY_SIZE, &writingPos)) {
+                return false;
+            }
+            mSize++;
+        }
+    }
+    const int probabilityWritingPos = getEntryPos(terminalId)
+            + Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE;
+    return getWritableBuffer()->writeUint(probability,
+            Ver4DictConstants::PROBABILITY_SIZE, probabilityWritingPos);
+}
+
+bool ProbabilityDictContent::flushToFile(const char *const dictDirPath) const {
+    if (getEntryPos(mSize) < getBuffer()->getTailPosition()) {
+        ProbabilityDictContent probabilityDictContentToWrite;
+        for (int i = 0; i < mSize; ++i) {
+            if (!probabilityDictContentToWrite.setProbability(i, getProbability(i))) {
+                return false;
+            }
+        }
+        return probabilityDictContentToWrite.flush(dictDirPath,
+                Ver4DictConstants::FREQ_FILE_EXTENSION);
+    } else {
+        return flush(dictDirPath, Ver4DictConstants::FREQ_FILE_EXTENSION);
+    }
+}
+
+bool ProbabilityDictContent::runGC(
+        const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+        const ProbabilityDictContent *const originalProbabilityDictContent) {
+    mSize = 0;
+    for (TerminalPositionLookupTable::TerminalIdMap::const_iterator it = terminalIdMap->begin();
+            it != terminalIdMap->end(); ++it) {
+        if (!setProbability(it->second,
+                originalProbabilityDictContent->getProbability(it->first))) {
+            return false;
+        }
+        mSize++;
+    }
+    return true;
+}
+
+int ProbabilityDictContent::getEntryPos(const int terminalId) const {
+    return terminalId * (Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE
+            + Ver4DictConstants::PROBABILITY_SIZE);
+}
+
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/probability_dict_content.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/probability_dict_content.h
index 0958dd1..0971ee0 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/probability_dict_content.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/probability_dict_content.h
@@ -21,7 +21,6 @@
 #include "suggest/policyimpl/dictionary/structure/v4/content/single_dict_content.h"
 #include "suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h"
 #include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h"
 #include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
@@ -35,76 +34,19 @@
 
     ProbabilityDictContent() : mSize(0) {}
 
-    int getProbability(const int terminalId) const {
-        if (terminalId < 0 || terminalId >= mSize) {
-            return NOT_A_PROBABILITY;
-        }
-        return Ver4PatriciaTrieReadingUtils::getProbability(getBuffer(), terminalId);
-    }
+    int getProbability(const int terminalId) const;
 
-    bool setProbability(const int terminalId, const int probability) {
-        if (terminalId < 0) {
-            return false;
-        }
-        if (terminalId >= mSize) {
-            // Write new entry.
-            int writingPos = getBuffer()->getTailPosition();
-            while (writingPos <= getEntryPos(terminalId)) {
-                const int dummyFlags = 0;
-                if (!getWritableBuffer()->writeUintAndAdvancePosition(dummyFlags,
-                        Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE, &writingPos)) {
-                    return false;
-                }
-                const int dummyProbability = 0;
-                if (!getWritableBuffer()->writeUintAndAdvancePosition(dummyProbability,
-                        Ver4DictConstants::PROBABILITY_SIZE, &writingPos)) {
-                    return false;
-                }
-                mSize++;
-            }
-        }
-        const int probabilityWritingPos = getEntryPos(terminalId)
-                + Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE;
-        return getWritableBuffer()->writeUint(probability,
-                Ver4DictConstants::PROBABILITY_SIZE, probabilityWritingPos);
-    }
+    bool setProbability(const int terminalId, const int probability);
 
-    bool flushToFile(const char *const dictDirPath) const {
-        if (getEntryPos(mSize) < getBuffer()->getTailPosition()) {
-            ProbabilityDictContent probabilityDictContentToWrite;
-            for (int i = 0; i < mSize; ++i) {
-                if (!probabilityDictContentToWrite.setProbability(i, getProbability(i))) {
-                    return false;
-                }
-            }
-            return probabilityDictContentToWrite.flush(dictDirPath,
-                    Ver4DictConstants::FREQ_FILE_EXTENSION);
-        } else {
-            return flush(dictDirPath, Ver4DictConstants::FREQ_FILE_EXTENSION);
-        }
-    }
+    bool flushToFile(const char *const dictDirPath) const;
 
     bool runGC(const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
-            const ProbabilityDictContent *const originalProbabilityDictContent) {
-        mSize = 0;
-        for (TerminalPositionLookupTable::TerminalIdMap::const_iterator it = terminalIdMap->begin();
-                it != terminalIdMap->end(); ++it) {
-            if (!setProbability(it->second,
-                    originalProbabilityDictContent->getProbability(it->first))) {
-                return false;
-            }
-            mSize++;
-        }
-        return true;
-    }
+            const ProbabilityDictContent *const originalProbabilityDictContent);
 
  private:
     DISALLOW_COPY_AND_ASSIGN(ProbabilityDictContent);
 
-    int getEntryPos(const int terminalId) const {
-        return terminalId * (Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE
-                + Ver4DictConstants::PROBABILITY_SIZE);
-    }
+    int getEntryPos(const int terminalId) const;
 
     int mSize;
 };
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.cpp
index b18bdc9..e9fba79 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.cpp
@@ -19,6 +19,7 @@
 #include "suggest/policyimpl/dictionary/structure/v2/patricia_trie_reading_utils.h"
 #include "suggest/policyimpl/dictionary/structure/v3/dynamic_patricia_trie_reading_utils.h"
 #include "suggest/policyimpl/dictionary/structure/v4/content/probability_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h"
 #include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {