jamesge commented on a change in pull request #979: Add LZ4 compression method URL: https://github.com/apache/incubator-brpc/pull/979#discussion_r352004994
########## File path: src/brpc/policy/lz4_compress.cpp ########## @@ -0,0 +1,184 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you 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. + +// Authors: Jiang,Lin ([email protected]) + +#include <memory> + +#include "butil/logging.h" +#include "butil/third_party/lz4/lz4.h" +#include "brpc/policy/lz4_compress.h" +#include "brpc/protocol.h" +#include "butil/third_party/snappy/snappy-internal.h" + +using namespace butil; +using namespace std; +using butil::snappy::Varint; + +namespace brpc { +namespace policy { + +// This is a helper function for both LZ4Compress and LZ4Decompress to choose whether +// use the heap buffer of the buffer from IOBufAsZeroCopyOutputStream. +static char *PrepareOutputBuffer(IOBufAsZeroCopyOutputStream& ostream, int sizeRequired, + unique_ptr<char[]>& bufferManager, int &noneHeapBufLen) { + char *outputBuf = nullptr; + int outputAvailableSize = 0; + ostream.Next(reinterpret_cast<void**>(&outputBuf), &outputAvailableSize); + if (outputAvailableSize >= sizeRequired) { + noneHeapBufLen = outputAvailableSize; + return outputBuf; + } else { + bufferManager.reset(new char[sizeRequired]); + ostream.BackUp(outputAvailableSize); + noneHeapBufLen = 0; + return bufferManager.get(); + } +} + +bool LZ4Compress(const butil::IOBuf& in, butil::IOBuf* out) { + // Encode the raw data length into the output buffer. + size_t len = in.length(); + char ulength[Varint::kMax32]; + char* p = Varint::Encode32(ulength, len); + out->append(ulength, p - ulength); + // Prepare the input buffer. + // If the IOBuf contains all the data in one buffer, use it without memcpy. + std::unique_ptr<char[]> inputBufManager; + std::unique_ptr<char[]> outputBufManager; + IOBufAsZeroCopyInputStream istream(in); + int inputBufSize = 0; + const char *inputBuf = nullptr; + istream.Next(reinterpret_cast<const void**>(&inputBuf), &inputBufSize); + const char *inputFullBuffer = nullptr; + if (static_cast<size_t>(inputBufSize) == len) { + inputFullBuffer = inputBuf; + } else { + inputBufManager.reset(new char[len]); + int currentPos = 0; + do { + memcpy(inputBufManager.get() + currentPos, inputBuf, inputBufSize); + currentPos += inputBufSize; + } while (istream.Next(reinterpret_cast<const void**>(&inputBuf), &inputBufSize)); + inputFullBuffer = inputBufManager.get(); + } + // Prepare the output buffer. + int sizeBound = LZ4_compressBound(len); + int noneHeapBufLen = 0; + IOBufAsZeroCopyOutputStream ostream(out); + char *outputFullBuffer = PrepareOutputBuffer(ostream, sizeBound, outputBufManager, noneHeapBufLen); + // Do the compression. + int compressLen = LZ4_compress_default(inputFullBuffer, outputFullBuffer, len, sizeBound); + if (compressLen < 0) { + return false; + } + if (noneHeapBufLen > 0) { + // This buffer is from output IOBuf. + ostream.BackUp(noneHeapBufLen - compressLen); + } else { + // This buffer is from heap. + out->append(outputFullBuffer, compressLen); + } + return true; +} + +bool LZ4Decompress(const butil::IOBuf& in, butil::IOBuf* out) { + int len = in.length(); + int inputBufSize = 0; + const char *inputBuf = nullptr; + IOBufAsZeroCopyInputStream istream(in); + istream.Next(reinterpret_cast<const void**>(&inputBuf), &inputBufSize); Review comment: Use IOBuf::backing_block instead ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
