| /* GENERATED SOURCE. DO NOT MODIFY. */ |
| /* |
| * Copyright (C) 2014 Square, Inc. |
| * |
| * 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.okhttp.okio; |
| |
| import java.io.IOException; |
| import java.util.zip.CRC32; |
| import java.util.zip.Deflater; |
| |
| import static java.util.zip.Deflater.DEFAULT_COMPRESSION; |
| |
| /** |
| * A sink that uses <a href="http://www.ietf.org/rfc/rfc1952.txt">GZIP</a> to |
| * compress written data to another sink. |
| * |
| * <h3>Sync flush</h3> |
| * Aggressive flushing of this stream may result in reduced compression. Each |
| * call to {@link #flush} immediately compresses all currently-buffered data; |
| * this early compression may be less effective than compression performed |
| * without flushing. |
| * |
| * <p>This is equivalent to using {@link Deflater} with the sync flush option. |
| * This class does not offer any partial flush mechanism. For best performance, |
| * only call {@link #flush} when application behavior requires it. |
| * @hide This class is not part of the Android public SDK API |
| */ |
| public final class GzipSink implements Sink { |
| /** Sink into which the GZIP format is written. */ |
| private final BufferedSink sink; |
| |
| /** The deflater used to compress the body. */ |
| private final Deflater deflater; |
| |
| /** |
| * The deflater sink takes care of moving data between decompressed source and |
| * compressed sink buffers. |
| */ |
| private final DeflaterSink deflaterSink; |
| |
| private boolean closed; |
| |
| /** Checksum calculated for the compressed body. */ |
| private final CRC32 crc = new CRC32(); |
| |
| public GzipSink(Sink sink) { |
| if (sink == null) throw new IllegalArgumentException("sink == null"); |
| this.deflater = new Deflater(DEFAULT_COMPRESSION, true /* No wrap */); |
| this.sink = Okio.buffer(sink); |
| this.deflaterSink = new DeflaterSink(this.sink, deflater); |
| |
| writeHeader(); |
| } |
| |
| @Override public void write(Buffer source, long byteCount) throws IOException { |
| if (byteCount < 0) throw new IllegalArgumentException("byteCount < 0: " + byteCount); |
| if (byteCount == 0) return; |
| |
| updateCrc(source, byteCount); |
| deflaterSink.write(source, byteCount); |
| } |
| |
| @Override public void flush() throws IOException { |
| deflaterSink.flush(); |
| } |
| |
| @Override public Timeout timeout() { |
| return sink.timeout(); |
| } |
| |
| @Override public void close() throws IOException { |
| if (closed) return; |
| |
| // This method delegates to the DeflaterSink for finishing the deflate process |
| // but keeps responsibility for releasing the deflater's resources. This is |
| // necessary because writeFooter needs to query the processed byte count which |
| // only works when the deflater is still open. |
| |
| Throwable thrown = null; |
| try { |
| deflaterSink.finishDeflate(); |
| writeFooter(); |
| } catch (Throwable e) { |
| thrown = e; |
| } |
| |
| try { |
| deflater.end(); |
| } catch (Throwable e) { |
| if (thrown == null) thrown = e; |
| } |
| |
| try { |
| sink.close(); |
| } catch (Throwable e) { |
| if (thrown == null) thrown = e; |
| } |
| closed = true; |
| |
| if (thrown != null) Util.sneakyRethrow(thrown); |
| } |
| |
| private void writeHeader() { |
| // Write the Gzip header directly into the buffer for the sink to avoid handling IOException. |
| Buffer buffer = this.sink.buffer(); |
| buffer.writeShort(0x1f8b); // Two-byte Gzip ID. |
| buffer.writeByte(0x08); // 8 == Deflate compression method. |
| buffer.writeByte(0x00); // No flags. |
| buffer.writeInt(0x00); // No modification time. |
| buffer.writeByte(0x00); // No extra flags. |
| buffer.writeByte(0x00); // No OS. |
| } |
| |
| private void writeFooter() throws IOException { |
| sink.writeIntLe((int) crc.getValue()); // CRC of original data. |
| sink.writeIntLe(deflater.getTotalIn()); // Length of original data. |
| } |
| |
| /** Updates the CRC with the given bytes. */ |
| private void updateCrc(Buffer buffer, long byteCount) { |
| for (Segment head = buffer.head; byteCount > 0; head = head.next) { |
| int segmentLength = (int) Math.min(byteCount, head.limit - head.pos); |
| crc.update(head.data, head.pos, segmentLength); |
| byteCount -= segmentLength; |
| } |
| } |
| } |