1 /* 2 * Copyright (C) 2018 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 // Functions to compress and decompress low entropy entries in the model. 18 19 #ifndef LIBTEXTCLASSIFIER_UTILS_ZLIB_ZLIB_H_ 20 #define LIBTEXTCLASSIFIER_UTILS_ZLIB_ZLIB_H_ 21 22 #include <vector> 23 24 #include "utils/base/integral_types.h" 25 #include "utils/zlib/buffer_generated.h" 26 #include <zlib.h> 27 28 namespace libtextclassifier3 { 29 30 class ZlibDecompressor { 31 public: 32 static std::unique_ptr<ZlibDecompressor> Instance( 33 const unsigned char* dictionary = nullptr, 34 unsigned int dictionary_size = 0); 35 ~ZlibDecompressor(); 36 37 bool Decompress(const uint8* buffer, const int buffer_size, 38 const int uncompressed_size, std::string* out); 39 bool MaybeDecompress(const CompressedBuffer* compressed_buffer, 40 std::string* out); 41 bool MaybeDecompress(const CompressedBufferT* compressed_buffer, 42 std::string* out); 43 bool MaybeDecompressOptionallyCompressedBuffer( 44 const flatbuffers::String* uncompressed_buffer, 45 const CompressedBuffer* compressed_buffer, std::string* out); 46 bool MaybeDecompressOptionallyCompressedBuffer( 47 const flatbuffers::Vector<uint8>* uncompressed_buffer, 48 const CompressedBuffer* compressed_buffer, std::string* out); 49 50 private: 51 ZlibDecompressor(const unsigned char* dictionary, 52 const unsigned int dictionary_size); 53 z_stream stream_; 54 bool initialized_; 55 }; 56 57 class ZlibCompressor { 58 public: 59 static std::unique_ptr<ZlibCompressor> Instance( 60 const unsigned char* dictionary = nullptr, 61 unsigned int dictionary_size = 0); 62 ~ZlibCompressor(); 63 64 void Compress(const std::string& uncompressed_content, 65 CompressedBufferT* out); 66 67 bool GetDictionary(std::vector<unsigned char>* dictionary); 68 69 private: 70 explicit ZlibCompressor(const unsigned char* dictionary = nullptr, 71 const unsigned int dictionary_size = 0, 72 const int level = Z_BEST_COMPRESSION, 73 // Tmp. buffer size was set based on the current set 74 // of patterns to be compressed. 75 const int tmp_buffer_size = 64 * 1024); 76 z_stream stream_; 77 std::unique_ptr<Bytef[]> buffer_; 78 unsigned int buffer_size_; 79 bool initialized_; 80 }; 81 82 } // namespace libtextclassifier3 83 84 #endif // LIBTEXTCLASSIFIER_UTILS_ZLIB_ZLIB_H_ 85