| /* |
| * Copyright (C) 2015 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 android.os; |
| |
| import java.util.HashMap; |
| |
| /** |
| * Helper class for writing pooled strings into a Parcel. It must be used |
| * in conjunction with {@link android.os.PooledStringReader}. This really needs |
| * to be pushed in to Parcel itself, but doing that is... complicated. |
| * @hide |
| */ |
| public class PooledStringWriter { |
| private final Parcel mOut; |
| |
| /** |
| * Book-keeping for writing pooled string objects, mapping strings we have |
| * written so far to their index in the pool. We deliberately use HashMap |
| * here since performance is critical, we expect to be doing lots of adds to |
| * it, and it is only a temporary object so its overall memory footprint is |
| * not a signifciant issue. |
| */ |
| private final HashMap<String, Integer> mPool; |
| |
| /** |
| * Book-keeping for writing pooling string objects, indicating where we |
| * started writing the pool, which is where we need to ultimately store |
| * how many strings are in the pool. |
| */ |
| private int mStart; |
| |
| /** |
| * Next available index in the pool. |
| */ |
| private int mNext; |
| |
| public PooledStringWriter(Parcel out) { |
| mOut = out; |
| mPool = new HashMap<>(); |
| mStart = out.dataPosition(); |
| out.writeInt(0); // reserve space for final pool size. |
| } |
| |
| public void writeString(String str) { |
| final Integer cur = mPool.get(str); |
| if (cur != null) { |
| mOut.writeInt(cur); |
| } else { |
| mPool.put(str, mNext); |
| mOut.writeInt(-(mNext+1)); |
| mOut.writeString(str); |
| mNext++; |
| } |
| } |
| |
| public int getStringCount() { |
| return mPool.size(); |
| } |
| |
| public void finish() { |
| final int pos = mOut.dataPosition(); |
| mOut.setDataPosition(mStart); |
| mOut.writeInt(mNext); |
| mOut.setDataPosition(pos); |
| } |
| } |