Alex Deymo | 68c0e7f | 2017-10-02 20:38:12 +0200 | [diff] [blame] | 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_DIFF_ENCODER_H_ |
| 6 | #define _BSDIFF_DIFF_ENCODER_H_ |
| 7 | |
| 8 | #include <stdint.h> |
| 9 | |
| 10 | #include "bsdiff/bz2_compressor.h" |
| 11 | #include "bsdiff/patch_writer_interface.h" |
| 12 | |
| 13 | namespace bsdiff { |
| 14 | |
| 15 | // Helper class to encapsulate the diff and extra stream generation logic |
| 16 | // derived from the old and new file buffers. Using this class is impossible to |
| 17 | // produce an invalid or incomplete bsdiff patch, since it has checks in place |
| 18 | // verifying its correct usage. |
| 19 | |
| 20 | class DiffEncoder { |
| 21 | public: |
| 22 | // Initialize the DiffEncoder with the old and new file buffers, as well as |
Alex Deymo | 4dadd8b | 2017-10-26 16:19:33 +0200 | [diff] [blame] | 23 | // the path writer used. The |patch| will be initialized when calling Init(). |
Alex Deymo | 68c0e7f | 2017-10-02 20:38:12 +0200 | [diff] [blame] | 24 | DiffEncoder(PatchWriterInterface* patch, |
| 25 | const uint8_t* old_buf, |
| 26 | uint64_t old_size, |
| 27 | const uint8_t* new_buf, |
| 28 | uint64_t new_size) |
| 29 | : patch_(patch), |
| 30 | old_buf_(old_buf), |
| 31 | old_size_(old_size), |
| 32 | new_buf_(new_buf), |
| 33 | new_size_(new_size) {} |
| 34 | |
Alex Deymo | 4dadd8b | 2017-10-26 16:19:33 +0200 | [diff] [blame] | 35 | // Initialize the diff encoder and the underlying patch. |
| 36 | bool Init(); |
| 37 | |
Alex Deymo | 68c0e7f | 2017-10-02 20:38:12 +0200 | [diff] [blame] | 38 | // Add a new control triplet entry to the patch. The |entry.diff_size| bytes |
| 39 | // for the diff stream and the |entry.extra_size| bytes for the extra stream |
| 40 | // will be computed and added to the corresponding streams in the patch. |
| 41 | // Returns whether the operation succeeded. The operation can fail if either |
| 42 | // the old or new files are referenced out of bounds. |
| 43 | bool AddControlEntry(const ControlEntry& entry); |
| 44 | |
| 45 | // Finalize the patch writing process and close the underlying patch writer. |
| 46 | bool Close(); |
| 47 | |
| 48 | private: |
| 49 | // Pointer to the patch we are writing to. |
| 50 | PatchWriterInterface* patch_; |
| 51 | |
| 52 | // Old and new file buffers. |
| 53 | const uint8_t* old_buf_; |
| 54 | uint64_t old_size_; |
| 55 | const uint8_t* new_buf_; |
| 56 | uint64_t new_size_; |
| 57 | |
| 58 | // Bytes of the new_buf_ already written. |
| 59 | uint64_t written_output_{0}; |
| 60 | |
| 61 | // The current position in the old buf. |
| 62 | int64_t old_pos_{0}; |
| 63 | }; |
| 64 | |
| 65 | } // namespace bsdiff |
| 66 | |
| 67 | #endif // _BSDIFF_DIFF_ENCODER_H_ |