diff --git a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
index c895a86..86c2394 100644
--- a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
+++ b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
@@ -18,42 +18,24 @@
 
 #include "com_android_inputmethod_latin_BinaryDictionary.h"
 
-#include <cerrno>
 #include <cstring> // for memset()
-#include <fcntl.h>
-#include <sys/mman.h>
-#include <unistd.h>
 
 #include "defines.h"
 #include "jni.h"
 #include "jni_common.h"
-#include "suggest/core/dictionary/binary_dictionary_info.h"
 #include "suggest/core/dictionary/dictionary.h"
 #include "suggest/core/suggest_options.h"
-#include "suggest/policyimpl/dictionary/utils/format_utils.h"
+#include "suggest/policyimpl/dictionary/dictionary_structure_with_buffer_policy_factory.h"
 #include "utils/autocorrection_threshold_utils.h"
 
 namespace latinime {
 
 class ProximityInfo;
 
-// Helper method
-static void releaseDictBuf(const void *dictBuf, const size_t length, const int fd) {
-    int ret = munmap(const_cast<void *>(dictBuf), length);
-    if (ret != 0) {
-        AKLOGE("DICT: Failure in munmap. ret=%d errno=%d", ret, errno);
-    }
-    ret = close(fd);
-    if (ret != 0) {
-        AKLOGE("DICT: Failure in close. ret=%d errno=%d", ret, errno);
-    }
-}
-
 static jlong latinime_BinaryDictionary_open(JNIEnv *env, jclass clazz, jstring sourceDir,
         jlong dictOffset, jlong dictSize, jboolean isUpdatable) {
     PROF_OPEN;
     PROF_START(66);
-    // TODO: Move dictionary buffer handling to policyimpl.
     const jsize sourceDirUtf8Length = env->GetStringUTFLength(sourceDir);
     if (sourceDirUtf8Length <= 0) {
         AKLOGE("DICT: Can't get sourceDir string");
@@ -62,41 +44,16 @@
     char sourceDirChars[sourceDirUtf8Length + 1];
     env->GetStringUTFRegion(sourceDir, 0, env->GetStringLength(sourceDir), sourceDirChars);
     sourceDirChars[sourceDirUtf8Length] = '\0';
-    int fd = 0;
-    void *dictBuf = 0;
-    int offset = 0;
-    const bool updatableMmap = (isUpdatable == JNI_TRUE);
-    const int openMode = updatableMmap ? O_RDWR : O_RDONLY;
-    fd = open(sourceDirChars, openMode);
-    if (fd < 0) {
-        AKLOGE("DICT: Can't open sourceDir. sourceDirChars=%s errno=%d", sourceDirChars, errno);
+    DictionaryStructureWithBufferPolicy *const dictionaryStructureWithBufferPolicy =
+            DictionaryStructureWithBufferPolicyFactory::newDictionaryStructureWithBufferPolicy(
+                    sourceDirChars, static_cast<int>(sourceDirUtf8Length),
+                    static_cast<int>(dictOffset), static_cast<int>(dictSize),
+                    isUpdatable == JNI_TRUE);
+    if (!dictionaryStructureWithBufferPolicy) {
         return 0;
     }
-    int pagesize = getpagesize();
-    offset = static_cast<int>(dictOffset) % pagesize;
-    int adjDictOffset = static_cast<int>(dictOffset) - offset;
-    int adjDictSize = static_cast<int>(dictSize) + offset;
-    const int protMode = updatableMmap ? PROT_READ | PROT_WRITE : PROT_READ;
-    dictBuf = mmap(0, adjDictSize, protMode, MAP_PRIVATE, fd, adjDictOffset);
-    if (dictBuf == MAP_FAILED) {
-        AKLOGE("DICT: Can't mmap dictionary. errno=%d", errno);
-        return 0;
-    }
-    dictBuf = static_cast<char *>(dictBuf) + offset;
-    if (!dictBuf) {
-        AKLOGE("DICT: dictBuf is null");
-        return 0;
-    }
-    Dictionary *dictionary = 0;
-    if (FormatUtils::UNKNOWN_VERSION
-            == FormatUtils::detectFormatVersion(static_cast<uint8_t *>(dictBuf),
-                    static_cast<int>(dictSize))) {
-        AKLOGE("DICT: dictionary format is unknown, bad magic number");
-        releaseDictBuf(static_cast<const char *>(dictBuf) - offset, adjDictSize, fd);
-    } else {
-        dictionary = new Dictionary(env, dictBuf, static_cast<int>(dictSize), fd, offset,
-                updatableMmap);
-    }
+
+    Dictionary *const dictionary = new Dictionary(env, dictionaryStructureWithBufferPolicy);
     PROF_END(66);
     PROF_CLOSE;
     return reinterpret_cast<jlong>(dictionary);
@@ -105,13 +62,6 @@
 static void latinime_BinaryDictionary_close(JNIEnv *env, jclass clazz, jlong dict) {
     Dictionary *dictionary = reinterpret_cast<Dictionary *>(dict);
     if (!dictionary) return;
-    const BinaryDictionaryInfo *const binaryDictionaryInfo = dictionary->getBinaryDictionaryInfo();
-    const int dictBufOffset = binaryDictionaryInfo->getDictBufOffset();
-    const void *dictBuf = binaryDictionaryInfo->getDictBuf();
-    if (!dictBuf) return;
-    releaseDictBuf(static_cast<const char *>(dictBuf) - dictBufOffset,
-            binaryDictionaryInfo->getDictSize() + dictBufOffset,
-            binaryDictionaryInfo->getMmapFd());
     delete dictionary;
 }
 
diff --git a/native/jni/src/suggest/core/dictionary/binary_dictionary_info.h b/native/jni/src/suggest/core/dictionary/binary_dictionary_info.h
deleted file mode 100644
index 7f646e3..0000000
--- a/native/jni/src/suggest/core/dictionary/binary_dictionary_info.h
+++ /dev/null
@@ -1,65 +0,0 @@
-/*
- * 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_BINARY_DICTIONARY_INFO_H
-#define LATINIME_BINARY_DICTIONARY_INFO_H
-
-#include <stdint.h>
-
-#include "defines.h"
-
-namespace latinime {
-
-class BinaryDictionaryInfo {
- public:
-     AK_FORCE_INLINE BinaryDictionaryInfo(const uint8_t *const dictBuf,
-            const int dictSize, const int mmapFd, const int dictBufOffset, const bool isUpdatable)
-            : mDictBuf(dictBuf), mDictSize(dictSize), mMmapFd(mmapFd),
-              mDictBufOffset(dictBufOffset), mIsUpdatable(isUpdatable) {}
-
-    ~BinaryDictionaryInfo() {}
-
-    AK_FORCE_INLINE const uint8_t *getDictBuf() const {
-        return mDictBuf;
-    }
-
-    AK_FORCE_INLINE int getDictSize() const {
-        return mDictSize;
-    }
-
-    AK_FORCE_INLINE int getMmapFd() const {
-        return mMmapFd;
-    }
-
-    AK_FORCE_INLINE int getDictBufOffset() const {
-        return mDictBufOffset;
-    }
-
-    AK_FORCE_INLINE bool isDynamicallyUpdatable() const {
-        return mIsUpdatable;
-    }
-
- private:
-    DISALLOW_COPY_AND_ASSIGN(BinaryDictionaryInfo);
-
-    const uint8_t *const mDictBuf;
-    const int mDictSize;
-    const int mMmapFd;
-    const int mDictBufOffset;
-    const bool mIsUpdatable;
-};
-}
-#endif /* LATINIME_BINARY_DICTIONARY_INFO_H */
diff --git a/native/jni/src/suggest/core/dictionary/dictionary.cpp b/native/jni/src/suggest/core/dictionary/dictionary.cpp
index 2ffd494..8418a60 100644
--- a/native/jni/src/suggest/core/dictionary/dictionary.cpp
+++ b/native/jni/src/suggest/core/dictionary/dictionary.cpp
@@ -23,23 +23,19 @@
 #include "defines.h"
 #include "suggest/core/dictionary/bigram_dictionary.h"
 #include "suggest/core/policy/dictionary_header_structure_policy.h"
+#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
 #include "suggest/core/session/dic_traverse_session.h"
 #include "suggest/core/suggest.h"
 #include "suggest/core/suggest_options.h"
-#include "suggest/policyimpl/dictionary/dictionary_structure_with_buffer_policy_factory.h"
 #include "suggest/policyimpl/gesture/gesture_suggest_policy_factory.h"
 #include "suggest/policyimpl/typing/typing_suggest_policy_factory.h"
 #include "utils/log_utils.h"
 
 namespace latinime {
 
-Dictionary::Dictionary(JNIEnv *env, void *dict, int dictSize, int mmapFd,
-        int dictBufOffset, bool isUpdatable)
-        : mBinaryDictionaryInfo(static_cast<const uint8_t *>(dict), dictSize, mmapFd,
-                dictBufOffset, isUpdatable),
-          mDictionaryStructureWithBufferPolicy(DictionaryStructureWithBufferPolicyFactory
-                  ::newDictionaryStructureWithBufferPolicy(
-                          static_cast<const uint8_t *>(dict), dictSize)),
+Dictionary::Dictionary(JNIEnv *env,
+        DictionaryStructureWithBufferPolicy *const dictionaryStructureWithBufferPolicy)
+        : mDictionaryStructureWithBufferPolicy(dictionaryStructureWithBufferPolicy),
           mBigramDictionary(new BigramDictionary(mDictionaryStructureWithBufferPolicy)),
           mGestureSuggest(new Suggest(GestureSuggestPolicyFactory::getGestureSuggestPolicy())),
           mTypingSuggest(new Suggest(TypingSuggestPolicyFactory::getTypingSuggestPolicy())) {
@@ -102,32 +98,17 @@
 }
 
 void Dictionary::addUnigramWord(const int *const word, const int length, const int probability) {
-    if (!mBinaryDictionaryInfo.isDynamicallyUpdatable()) {
-        // This method should not be called for non-updatable dictionary.
-        AKLOGI("Warning: Dictionary::addUnigramWord() is called for non-updatable dictionary.");
-        return;
-    }
     mDictionaryStructureWithBufferPolicy->addUnigramWord(word, length, probability);
 }
 
 void Dictionary::addBigramWords(const int *const word0, const int length0, const int *const word1,
         const int length1, const int probability) {
-    if (!mBinaryDictionaryInfo.isDynamicallyUpdatable()) {
-        // This method should not be called for non-updatable dictionary.
-        AKLOGI("Warning: Dictionary::addBigramWords() is called for non-updatable dictionary.");
-        return;
-    }
     mDictionaryStructureWithBufferPolicy->addBigramWords(word0, length0, word1, length1,
             probability);
 }
 
 void Dictionary::removeBigramWords(const int *const word0, const int length0,
         const int *const word1, const int length1) {
-    if (!mBinaryDictionaryInfo.isDynamicallyUpdatable()) {
-        // This method should not be called for non-updatable dictionary.
-        AKLOGI("Warning: Dictionary::removeBigramWords() is called for non-updatable dictionary.");
-        return;
-    }
     mDictionaryStructureWithBufferPolicy->removeBigramWords(word0, length0, word1, length1);
 }
 
@@ -155,9 +136,8 @@
             dateStringCharBuffer, BUFFER_SIZE);
 
     LogUtils::logToJava(env,
-            "Dictionary info: dictionary = %s ; version = %s ; date = %s ; filesize = %i",
-            dictionaryIdCharBuffer, versionStringCharBuffer, dateStringCharBuffer,
-            mBinaryDictionaryInfo.getDictSize());
+            "Dictionary info: dictionary = %s ; version = %s ; date = %s",
+            dictionaryIdCharBuffer, versionStringCharBuffer, dateStringCharBuffer);
 }
 
 } // namespace latinime
diff --git a/native/jni/src/suggest/core/dictionary/dictionary.h b/native/jni/src/suggest/core/dictionary/dictionary.h
index a54b62f..0afe5a5 100644
--- a/native/jni/src/suggest/core/dictionary/dictionary.h
+++ b/native/jni/src/suggest/core/dictionary/dictionary.h
@@ -21,7 +21,6 @@
 
 #include "defines.h"
 #include "jni.h"
-#include "suggest/core/dictionary/binary_dictionary_info.h"
 
 namespace latinime {
 
@@ -54,8 +53,8 @@
     static const int KIND_FLAG_POSSIBLY_OFFENSIVE = 0x80000000;
     static const int KIND_FLAG_EXACT_MATCH = 0x40000000;
 
-    Dictionary(JNIEnv *env, void *dict, int dictSize, int mmapFd, int dictBufOffset,
-            bool isUpdatable);
+    Dictionary(JNIEnv *env,
+            DictionaryStructureWithBufferPolicy *const dictionaryStructureWithBufferPoilcy);
 
     int getSuggestions(ProximityInfo *proximityInfo, DicTraverseSession *traverseSession,
             int *xcoordinates, int *ycoordinates, int *times, int *pointerIds, int *inputCodePoints,
@@ -78,11 +77,6 @@
     void removeBigramWords(const int *const word0, const int length0, const int *const word1,
             const int length1);
 
-    // TODO: Remove.
-    const BinaryDictionaryInfo *getBinaryDictionaryInfo() const {
-        return &mBinaryDictionaryInfo;
-    }
-
     const DictionaryStructureWithBufferPolicy *getDictionaryStructurePolicy() const {
         return mDictionaryStructureWithBufferPolicy;
     }
@@ -92,7 +86,6 @@
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(Dictionary);
 
-    const BinaryDictionaryInfo mBinaryDictionaryInfo;
     DictionaryStructureWithBufferPolicy *const mDictionaryStructureWithBufferPolicy;
     const BigramDictionary *const mBigramDictionary;
     const SuggestInterface *const mGestureSuggest;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dictionary_structure_with_buffer_policy_factory.cpp b/native/jni/src/suggest/policyimpl/dictionary/dictionary_structure_with_buffer_policy_factory.cpp
index 34f092f..cc5252c 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dictionary_structure_with_buffer_policy_factory.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/dictionary_structure_with_buffer_policy_factory.cpp
@@ -22,18 +22,29 @@
 #include "suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.h"
 #include "suggest/policyimpl/dictionary/patricia_trie_policy.h"
 #include "suggest/policyimpl/dictionary/utils/format_utils.h"
+#include "suggest/policyimpl/dictionary/utils/mmaped_buffer.h"
 
 namespace latinime {
 
 /* static */ DictionaryStructureWithBufferPolicy *DictionaryStructureWithBufferPolicyFactory
-        ::newDictionaryStructureWithBufferPolicy(const uint8_t *const dictBuf,
-                const int dictSize) {
-    switch (FormatUtils::detectFormatVersion(dictBuf, dictSize)) {
+        ::newDictionaryStructureWithBufferPolicy(const char *const path, const int pathLength,
+                const int bufOffset, const int size, const bool isUpdatable) {
+    // Allocated buffer in MmapedBuffer::openBuffer() will be freed in the destructor of
+    // impl classes of DictionaryStructureWithBufferPolicy.
+    const MmapedBuffer *const mmapedBuffer = MmapedBuffer::openBuffer(path, pathLength, bufOffset,
+            size, isUpdatable);
+    if (!mmapedBuffer) {
+        return 0;
+    }
+    switch (FormatUtils::detectFormatVersion(mmapedBuffer->getBuffer(),
+            mmapedBuffer->getBufferSize())) {
         case FormatUtils::VERSION_2:
-            return new PatriciaTriePolicy(dictBuf);
+            return new PatriciaTriePolicy(mmapedBuffer);
         case FormatUtils::VERSION_3:
-            return new DynamicPatriciaTriePolicy(dictBuf);
+            return new DynamicPatriciaTriePolicy(mmapedBuffer);
         default:
+            AKLOGE("DICT: dictionary format is unknown, bad magic number");
+            delete mmapedBuffer;
             ASSERT(false);
             return 0;
     }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dictionary_structure_with_buffer_policy_factory.h b/native/jni/src/suggest/policyimpl/dictionary/dictionary_structure_with_buffer_policy_factory.h
index 53eb8f9..1cb7a89 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dictionary_structure_with_buffer_policy_factory.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/dictionary_structure_with_buffer_policy_factory.h
@@ -27,7 +27,8 @@
 class DictionaryStructureWithBufferPolicyFactory {
  public:
     static DictionaryStructureWithBufferPolicy *newDictionaryStructureWithBufferPolicy(
-            const uint8_t *const dictBuf, const int dictSize);
+            const char *const path, const int pathLength, const int bufOffset, const int size,
+            const bool isUpdatable);
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(DictionaryStructureWithBufferPolicyFactory);
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.cpp
index 311e94d..3000860 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.cpp
@@ -233,18 +233,30 @@
 
 bool DynamicPatriciaTriePolicy::addUnigramWord(const int *const word, const int length,
         const int probability) {
+    if (!mBuffer->isUpdatable()) {
+        AKLOGI("Warning: addUnigramWord() is called for non-updatable dictionary.");
+        return false;
+    }
     // TODO: Implement.
     return false;
 }
 
 bool DynamicPatriciaTriePolicy::addBigramWords(const int *const word0, const int length0,
         const int *const word1, const int length1, const int probability) {
+    if (!mBuffer->isUpdatable()) {
+        AKLOGI("Warning: addBigramWords() is called for non-updatable dictionary.");
+        return false;
+    }
     // TODO: Implement.
     return false;
 }
 
 bool DynamicPatriciaTriePolicy::removeBigramWords(const int *const word0, const int length0,
         const int *const word1, const int length1) {
+    if (!mBuffer->isUpdatable()) {
+        AKLOGI("Warning: removeBigramWords() is called for non-updatable dictionary.");
+        return false;
+    }
     // TODO: Implement.
     return false;
 }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.h b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.h
index 4a5192c..708967d 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.h
@@ -24,6 +24,7 @@
 #include "suggest/policyimpl/dictionary/bigram/bigram_list_policy.h"
 #include "suggest/policyimpl/dictionary/header/header_policy.h"
 #include "suggest/policyimpl/dictionary/shortcut/shortcut_list_policy.h"
+#include "suggest/policyimpl/dictionary/utils/mmaped_buffer.h"
 
 namespace latinime {
 
@@ -32,11 +33,14 @@
 
 class DynamicPatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
  public:
-    DynamicPatriciaTriePolicy(const uint8_t *const dictBuf)
-            : mHeaderPolicy(dictBuf), mDictRoot(dictBuf + mHeaderPolicy.getSize()),
+    DynamicPatriciaTriePolicy(const MmapedBuffer *const buffer)
+            : mBuffer(buffer), mHeaderPolicy(mBuffer->getBuffer()),
+              mDictRoot(mBuffer->getBuffer() + mHeaderPolicy.getSize()),
               mBigramListPolicy(mDictRoot), mShortcutListPolicy(mDictRoot) {}
 
-    ~DynamicPatriciaTriePolicy() {}
+    ~DynamicPatriciaTriePolicy() {
+        delete mBuffer;
+    }
 
     AK_FORCE_INLINE int getRootPosition() const {
         return 0;
@@ -82,6 +86,7 @@
     DISALLOW_IMPLICIT_CONSTRUCTORS(DynamicPatriciaTriePolicy);
     static const int MAX_CHILD_COUNT_TO_AVOID_INFINITE_LOOP;
 
+    const MmapedBuffer *const mBuffer;
     const HeaderPolicy mHeaderPolicy;
     // TODO: Consolidate mDictRoot.
     const uint8_t *const mDictRoot;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/patricia_trie_policy.h b/native/jni/src/suggest/policyimpl/dictionary/patricia_trie_policy.h
index 0ed7945..0d85050 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/patricia_trie_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/patricia_trie_policy.h
@@ -24,6 +24,7 @@
 #include "suggest/policyimpl/dictionary/bigram/bigram_list_policy.h"
 #include "suggest/policyimpl/dictionary/header/header_policy.h"
 #include "suggest/policyimpl/dictionary/shortcut/shortcut_list_policy.h"
+#include "suggest/policyimpl/dictionary/utils/mmaped_buffer.h"
 
 namespace latinime {
 
@@ -32,11 +33,14 @@
 
 class PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
  public:
-    PatriciaTriePolicy(const uint8_t *const dictBuf)
-            : mHeaderPolicy(dictBuf), mDictRoot(dictBuf + mHeaderPolicy.getSize()),
+    PatriciaTriePolicy(const MmapedBuffer *const buffer)
+            : mBuffer(buffer), mHeaderPolicy(mBuffer->getBuffer()),
+              mDictRoot(mBuffer->getBuffer() + mHeaderPolicy.getSize()),
               mBigramListPolicy(mDictRoot), mShortcutListPolicy(mDictRoot) {}
 
-    ~PatriciaTriePolicy() {}
+    ~PatriciaTriePolicy() {
+        delete mBuffer;
+    }
 
     AK_FORCE_INLINE int getRootPosition() const {
         return 0;
@@ -71,25 +75,29 @@
     }
 
     bool addUnigramWord(const int *const word, const int length, const int probability) {
-        // This dictionary format is not updatable.
+        // This method should not be called for non-updatable dictionary.
+        AKLOGI("Warning: addUnigramWord() is called for non-updatable dictionary.");
         return false;
     }
 
     bool addBigramWords(const int *const word0, const int length0, const int *const word1,
             const int length1, const int probability) {
-        // This dictionary format is not updatable.
+        // This method should not be called for non-updatable dictionary.
+        AKLOGI("Warning: addBigramWords() is called for non-updatable dictionary.");
         return false;
     }
 
     bool removeBigramWords(const int *const word0, const int length0, const int *const word1,
             const int length1) {
-        // This dictionary format is not updatable.
+        // This method should not be called for non-updatable dictionary.
+        AKLOGI("Warning: removeBigramWords() is called for non-updatable dictionary.");
         return false;
     }
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(PatriciaTriePolicy);
 
+    const MmapedBuffer *const mBuffer;
     const HeaderPolicy mHeaderPolicy;
     const uint8_t *const mDictRoot;
     const BigramListPolicy mBigramListPolicy;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/mmaped_buffer.h b/native/jni/src/suggest/policyimpl/dictionary/utils/mmaped_buffer.h
new file mode 100644
index 0000000..e3aabb0
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/mmaped_buffer.h
@@ -0,0 +1,99 @@
+/*
+ * 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_MMAPED_BUFFER_H
+#define LATINIME_MMAPED_BUFFER_H
+
+#include <cerrno>
+#include <fcntl.h>
+#include <stdint.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "defines.h"
+
+namespace latinime {
+
+class MmapedBuffer {
+ public:
+    static MmapedBuffer* openBuffer(const char *const path, const int pathLength,
+            const int bufOffset, const int size, const bool isUpdatable) {
+        const int openMode = isUpdatable ? O_RDWR : O_RDONLY;
+        const int fd = open(path, openMode);
+        if (fd < 0) {
+            AKLOGE("DICT: Can't open the source. path=%s errno=%d", path, errno);
+            return 0;
+        }
+        const int pagesize = getpagesize();
+        const int offset = bufOffset % pagesize;
+        int adjOffset = bufOffset - offset;
+        int adjSize = size + offset;
+        const int protMode = isUpdatable ? PROT_READ | PROT_WRITE : PROT_READ;
+        void *const mmapedBuffer = mmap(0, adjSize, protMode, MAP_PRIVATE, fd, adjOffset);
+        if (mmapedBuffer == MAP_FAILED) {
+            AKLOGE("DICT: Can't mmap dictionary. errno=%d", errno);
+            close(fd);
+            return 0;
+        }
+        uint8_t *const buffer = static_cast<uint8_t *>(mmapedBuffer) + bufOffset;
+        if (!buffer) {
+            AKLOGE("DICT: buffer is null");
+            close(fd);
+            return 0;
+        }
+        return new MmapedBuffer(buffer, adjSize, fd, adjOffset, isUpdatable);
+    }
+
+    ~MmapedBuffer() {
+        int ret = munmap(static_cast<void *>(mBuffer - mBufferOffset),
+                mBufferSize + mBufferOffset);
+        if (ret != 0) {
+            AKLOGE("DICT: Failure in munmap. ret=%d errno=%d", ret, errno);
+        }
+        ret = close(mMmapFd);
+        if (ret != 0) {
+            AKLOGE("DICT: Failure in close. ret=%d errno=%d", ret, errno);
+        }
+    }
+
+    AK_FORCE_INLINE uint8_t *getBuffer() const {
+        return mBuffer;
+    }
+
+    AK_FORCE_INLINE int getBufferSize() const {
+        return mBufferSize;
+    }
+
+    AK_FORCE_INLINE bool isUpdatable() const {
+        return mIsUpdatable;
+    }
+
+ private:
+    AK_FORCE_INLINE MmapedBuffer(uint8_t *const buffer, const int bufferSize, const int mmapFd,
+            const int bufferOffset, const bool isUpdatable)
+            : mBuffer(buffer), mBufferSize(bufferSize), mMmapFd(mmapFd),
+              mBufferOffset(bufferOffset), mIsUpdatable(isUpdatable) {}
+
+    DISALLOW_IMPLICIT_CONSTRUCTORS(MmapedBuffer);
+
+    uint8_t *const mBuffer;
+    const int mBufferSize;
+    const int mMmapFd;
+    const int mBufferOffset;
+    const bool mIsUpdatable;
+};
+}
+#endif /* LATINIME_MMAPED_BUFFER_H */