1 // 2 // Copyright (C) 2021 The Android Open Source Project 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 17 #ifndef UPDATE_ENGINE_LZ4DIFF_LZ4DIFF_COMPRESS_H_ 18 #define UPDATE_ENGINE_LZ4DIFF_LZ4DIFF_COMPRESS_H_ 19 20 #include "lz4diff_format.h" 21 #include <string_view> 22 23 namespace chromeos_update_engine { 24 25 using SinkFunc = std::function<size_t(const uint8_t*, size_t)>; 26 27 // |TryCompressBlob| and |TryDecompressBlob| are inverse function of each other. 28 // One compresses data into fixed size output chunks, one decompresses fixed 29 // size blocks. 30 // The |TryCompressBlob| routine is supposed to mimic how EROFS compresses input 31 // files when creating an EROFS image. After calling |TryCompressBlob|, LZ4DIFF 32 // will compare the re-compressed blob and EROFS's ground truth blob, and 33 // generate a BSDIFF patch between them if there's mismatch. Therefore, it is OK 34 // that |TryCompressBlob| produces slightly different output than mkfs.erofs, so 35 // as long as |TryCompressBlob| exhibits consistne bebavior across platforms. 36 Blob TryCompressBlob(std::string_view blob, 37 const std::vector<CompressedBlock>& block_info, 38 const bool zero_padding_enabled, 39 const CompressionAlgorithm compression_algo); 40 bool TryCompressBlob(std::string_view blob, 41 const std::vector<CompressedBlock>& block_info, 42 const bool zero_padding_enabled, 43 const CompressionAlgorithm compression_algo, 44 const SinkFunc& sink); 45 46 Blob TryDecompressBlob(std::string_view blob, 47 const std::vector<CompressedBlock>& block_info, 48 const bool zero_padding_enabled); 49 Blob TryDecompressBlob(const Blob& blob, 50 const std::vector<CompressedBlock>& block_info, 51 const bool zero_padding_enabled); 52 53 std::ostream& operator<<(std::ostream& out, const CompressedBlockInfo& info); 54 55 std::ostream& operator<<(std::ostream& out, const CompressedBlock& block); 56 57 } // namespace chromeos_update_engine 58 59 #endif 60