1 // Copyright 2017 The Chromium OS Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef _BSDIFF_PATCH_READER_H_ 6 #define _BSDIFF_PATCH_READER_H_ 7 8 #include <stddef.h> 9 #include <stdint.h> 10 11 #include <memory> 12 13 #include "bsdiff/control_entry.h" 14 #include "bsdiff/decompressor_interface.h" 15 #include "bsdiff/file_interface.h" 16 17 namespace bsdiff { 18 19 // A wrapper class to read and parse the data in a bsdiff patch. The reader 20 // class contains the concatenated streams of control, diff, and extra data. 21 // After initialization, this class provides the function to read the metadata 22 // embedded in the control stream sequentially and decompresses the diff & extra 23 // stream based on this metadata. 24 25 class BsdiffPatchReader { 26 public: 27 BsdiffPatchReader() = default; 28 29 // Initialize the control stream, diff stream and extra stream from the 30 // corresponding offset of |patch_data|. 31 bool Init(const uint8_t* patch_data, size_t patch_size); 32 33 // Read the control stream and parse the metadata of |diff_size_|, 34 // |extra_size_| and |offset_incremental_|. 35 bool ParseControlEntry(ControlEntry* control_entry); 36 37 // Read the data in |diff_stream_| and write |size| decompressed data to 38 // |buf|. 39 bool ReadDiffStream(uint8_t* buf, size_t size); 40 41 // Read the data in |extra_stream_| and write |size| decompressed data to 42 // |buf|. 43 bool ReadExtraStream(uint8_t* buf, size_t size); 44 45 uint64_t new_file_size() const { return new_file_size_; } 46 47 // Close the control/diff/extra stream. Return false if errors occur when 48 // closing any of these streams. 49 bool Finish(); 50 51 private: 52 // The compressed stream that contains the control data; i.e. length of each 53 // diff/extra block and the corresponding offset to read in the source file. 54 std::unique_ptr<DecompressorInterface> ctrl_stream_{nullptr}; 55 // The compressed stream that contains the concatenated diff blocks. 56 std::unique_ptr<DecompressorInterface> diff_stream_{nullptr}; 57 // The compressed stream that contains the concatenated extra blocks. 58 std::unique_ptr<DecompressorInterface> extra_stream_{nullptr}; 59 60 // Size of the target file. 61 uint64_t new_file_size_; 62 }; 63 64 } // namespace bsdiff 65 66 #endif // _BSDIFF_PATCH_READER_H_ 67
