• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * Copyright (C) 2017 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_ZLIB_UTILS_H_
20 #define LIBTEXTCLASSIFIER_ZLIB_UTILS_H_
21 
22 #include <memory>
23 
24 #include "model_generated.h"
25 #include "util/utf8/unilib.h"
26 #include "zlib.h"
27 
28 namespace libtextclassifier2 {
29 
30 class ZlibDecompressor {
31  public:
32   static std::unique_ptr<ZlibDecompressor> Instance();
33   ~ZlibDecompressor();
34 
35   bool Decompress(const CompressedBuffer* compressed_buffer, std::string* out);
36 
37  private:
38   ZlibDecompressor();
39   z_stream stream_;
40   bool initialized_;
41 };
42 
43 class ZlibCompressor {
44  public:
45   static std::unique_ptr<ZlibCompressor> Instance();
46   ~ZlibCompressor();
47 
48   void Compress(const std::string& uncompressed_content,
49                 CompressedBufferT* out);
50 
51  private:
52   explicit ZlibCompressor(int level = Z_BEST_COMPRESSION,
53                           // Tmp. buffer size was set based on the current set
54                           // of patterns to be compressed.
55                           int tmp_buffer_size = 64 * 1024);
56   z_stream stream_;
57   std::unique_ptr<Bytef[]> buffer_;
58   unsigned int buffer_size_;
59   bool initialized_;
60 };
61 
62 // Compresses regex and datetime rules in the model in place.
63 bool CompressModel(ModelT* model);
64 
65 // Decompresses regex and datetime rules in the model in place.
66 bool DecompressModel(ModelT* model);
67 
68 // Compresses regex and datetime rules in the model.
69 std::string CompressSerializedModel(const std::string& model);
70 
71 // Create and compile a regex pattern from optionally compressed pattern.
72 std::unique_ptr<UniLib::RegexPattern> UncompressMakeRegexPattern(
73     const UniLib& unilib, const flatbuffers::String* uncompressed_pattern,
74     const CompressedBuffer* compressed_pattern, ZlibDecompressor* decompressor,
75     std::string* result_pattern_text = nullptr);
76 
77 }  // namespace libtextclassifier2
78 
79 #endif  // LIBTEXTCLASSIFIER_ZLIB_UTILS_H_
80