diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.cpp b/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.cpp
index 8582c4b..6326754 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.cpp
@@ -22,4 +22,70 @@
 const size_t BufferWithExtendableBuffer::MAX_ADDITIONAL_BUFFER_SIZE = 1024 * 1024;
 const size_t BufferWithExtendableBuffer::EXTEND_ADDITIONAL_BUFFER_SIZE_STEP = 16 * 1024;
 
+bool BufferWithExtendableBuffer::writeUintAndAdvancePosition(const uint32_t data, const int size,
+        int *const pos) {
+    if (!(size >= 1 && size <= 4)) {
+        AKLOGI("writeUintAndAdvancePosition() is called with invalid size: %d", size);
+        ASSERT(false);
+        return false;
+    }
+    if (!checkAndPrepareWriting(*pos, size)) {
+        return false;
+    }
+    const bool usesAdditionalBuffer = isInAdditionalBuffer(*pos);
+    uint8_t *const buffer = usesAdditionalBuffer ? &mAdditionalBuffer[0] : mOriginalBuffer;
+    if (usesAdditionalBuffer) {
+        *pos -= mOriginalBufferSize;
+    }
+    ByteArrayUtils::writeUintAndAdvancePosition(buffer, data, size, pos);
+    if (usesAdditionalBuffer) {
+        *pos += mOriginalBufferSize;
+    }
+    return true;
+}
+
+bool BufferWithExtendableBuffer::writeCodePointsAndAdvancePosition(const int *const codePoints,
+        const int codePointCount, const bool writesTerminator ,int *const pos) {
+    const size_t size = ByteArrayUtils::calculateRequiredByteCountToStoreCodePoints(
+            codePoints, codePointCount, writesTerminator);
+    if (!checkAndPrepareWriting(*pos, size)) {
+        return false;
+    }
+    const bool usesAdditionalBuffer = isInAdditionalBuffer(*pos);
+    uint8_t *const buffer = usesAdditionalBuffer ? &mAdditionalBuffer[0] : mOriginalBuffer;
+    if (usesAdditionalBuffer) {
+        *pos -= mOriginalBufferSize;
+    }
+    ByteArrayUtils::writeCodePointsAndAdvancePosition(buffer, codePoints, codePointCount,
+            writesTerminator, pos);
+    if (usesAdditionalBuffer) {
+        *pos += mOriginalBufferSize;
+    }
+    return true;
+}
+
+bool BufferWithExtendableBuffer::checkAndPrepareWriting(const int pos, const int size) {
+    if (isInAdditionalBuffer(pos)) {
+        if (pos == mUsedAdditionalBufferSize) {
+            // Append data to the tail.
+            if (pos + size > static_cast<int>(mAdditionalBuffer.size())) {
+                // Need to extend buffer.
+                if (!extendBuffer()) {
+                    return false;
+                }
+            }
+            mUsedAdditionalBufferSize += size;
+        } else if (pos + size >= mUsedAdditionalBufferSize) {
+            // The access will beyond the tail of used region.
+            return false;
+        }
+    } else {
+        if (pos < 0 || mOriginalBufferSize < pos + size) {
+            // Invalid position or violate the boundary.
+            return false;
+        }
+    }
+    return true;
+}
+
 }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h b/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h
index ec871ec..b35b47d 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h
@@ -66,27 +66,10 @@
      * Writing is allowed for original buffer, already written region of additional buffer and the
      * tail of additional buffer.
      */
-    AK_FORCE_INLINE bool writeUintAndAdvancePosition(const uint32_t data, const int size,
-            int *const pos) {
-        if (!(size >= 1 && size <= 4)) {
-            AKLOGI("writeUintAndAdvancePosition() is called with invalid size: %d", size);
-            ASSERT(false);
-            return false;
-        }
-        if (!checkAndPrepareWriting(*pos, size)) {
-            return false;
-        }
-        const bool usesAdditionalBuffer = isInAdditionalBuffer(*pos);
-        uint8_t *const buffer = usesAdditionalBuffer ? &mAdditionalBuffer[0] : mOriginalBuffer;
-        if (usesAdditionalBuffer) {
-            *pos -= mOriginalBufferSize;
-        }
-        ByteArrayUtils::writeUintAndAdvancePosition(buffer, data, size, pos);
-        if (usesAdditionalBuffer) {
-            *pos += mOriginalBufferSize;
-        }
-        return true;
-    }
+    bool writeUintAndAdvancePosition(const uint32_t data, const int size, int *const pos);
+
+    bool writeCodePointsAndAdvancePosition(const int *const codePoints, const int codePointCount,
+            const bool writesTerminator, int *const pos);
 
  private:
     DISALLOW_COPY_AND_ASSIGN(BufferWithExtendableBuffer);
@@ -112,29 +95,7 @@
 
     // Returns if it is possible to write size-bytes from pos. When pos is at the tail position of
     // the additional buffer, try extending the buffer.
-    AK_FORCE_INLINE bool checkAndPrepareWriting(const int pos, const int size) {
-        if (isInAdditionalBuffer(pos)) {
-            if (pos == mUsedAdditionalBufferSize) {
-                // Append data to the tail.
-                if (pos + size > static_cast<int>(mAdditionalBuffer.size())) {
-                    // Need to extend buffer.
-                    if (!extendBuffer()) {
-                        return false;
-                    }
-                }
-                mUsedAdditionalBufferSize += size;
-            } else if (pos + size >= mUsedAdditionalBufferSize) {
-                // The access will beyond the tail of used region.
-                return false;
-            }
-        } else {
-            if (pos < 0 || mOriginalBufferSize < pos + size) {
-                // Invalid position or violate the boundary.
-                return false;
-            }
-        }
-        return true;
-    }
+    AK_FORCE_INLINE bool checkAndPrepareWriting(const int pos, const int size);
 };
 }
 #endif /* LATINIME_BUFFER_WITH_EXTENDABLE_BUFFER_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/byte_array_utils.h b/native/jni/src/suggest/policyimpl/dictionary/utils/byte_array_utils.h
index e2cb9a0..f727ecf 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/byte_array_utils.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/byte_array_utils.h
@@ -115,7 +115,7 @@
     }
 
     /**
-     * Code Point
+     * Code Point Reading
      *
      * 1 byte = bbbbbbbb match
      * case 000xxxxx: xxxxx << 16 + next byte << 8 + next byte
@@ -149,7 +149,7 @@
     }
 
     /**
-     * String (array of code points)
+     * String (array of code points) Reading
      *
      * Reads code points until the terminator is found.
      */
@@ -176,6 +176,51 @@
         return length;
     }
 
+    /**
+     * String (array of code points) Writing
+     */
+    static void writeCodePointsAndAdvancePosition(uint8_t *const buffer,
+            const int *const codePoints, const int codePointCount, const bool writesTerminator,
+            int *const pos) {
+        for (int i = 0; i < codePointCount; ++i) {
+            const int codePoint = codePoints[i];
+            if (codePoint == NOT_A_CODE_POINT || codePoint == CHARACTER_ARRAY_TERMINATOR) {
+                break;
+            } else if (codePoint < MINIMAL_ONE_BYTE_CHARACTER_VALUE) {
+                // three bytes character.
+                writeUint24AndAdvancePosition(buffer, codePoint, pos);
+            } else {
+                // one byte character.
+                writeUint8AndAdvancePosition(buffer, codePoint, pos);
+            }
+        }
+        if (writesTerminator) {
+            writeUint8AndAdvancePosition(buffer, CHARACTER_ARRAY_TERMINATOR, pos);
+        }
+    }
+
+    static int calculateRequiredByteCountToStoreCodePoints(const int *const codePoints,
+            const int codePointCount, const bool writesTerminator) {
+        int byteCount = 0;
+        for (int i = 0; i < codePointCount; ++i) {
+            const int codePoint = codePoints[i];
+            if (codePoint == NOT_A_CODE_POINT || codePoint == CHARACTER_ARRAY_TERMINATOR) {
+                break;
+            } else if (codePoint < MINIMAL_ONE_BYTE_CHARACTER_VALUE) {
+                // three bytes character.
+                byteCount += 3;
+            } else {
+                // one byte character.
+                byteCount += 1;
+            }
+        }
+        if (writesTerminator) {
+            // The terminator is one byte.
+            byteCount += 1;
+        }
+        return byteCount;
+    }
+
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(ByteArrayUtils);