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68 lines
2.1 KiB
68 lines
2.1 KiB
// Copyright 2017 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef _BSDIFF_DIFF_ENCODER_H_
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#define _BSDIFF_DIFF_ENCODER_H_
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#include <stdint.h>
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#include "bsdiff/bz2_compressor.h"
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#include "bsdiff/patch_writer_interface.h"
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namespace bsdiff {
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// Helper class to encapsulate the diff and extra stream generation logic
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// derived from the old and new file buffers. Using this class is impossible to
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// produce an invalid or incomplete bsdiff patch, since it has checks in place
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// verifying its correct usage.
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class DiffEncoder {
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public:
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// Initialize the DiffEncoder with the old and new file buffers, as well as
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// the path writer used. The |patch| will be initialized when calling Init().
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DiffEncoder(PatchWriterInterface* patch,
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const uint8_t* old_buf,
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uint64_t old_size,
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const uint8_t* new_buf,
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uint64_t new_size)
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: patch_(patch),
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old_buf_(old_buf),
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old_size_(old_size),
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new_buf_(new_buf),
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new_size_(new_size) {}
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// Initialize the diff encoder and the underlying patch.
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bool Init();
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// Add a new control triplet entry to the patch. The |entry.diff_size| bytes
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// for the diff stream and the |entry.extra_size| bytes for the extra stream
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// will be computed and added to the corresponding streams in the patch.
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// Returns whether the operation succeeded. The operation can fail if either
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// the old or new files are referenced out of bounds.
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bool AddControlEntry(const ControlEntry& entry);
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// Finalize the patch writing process and close the underlying patch writer.
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bool Close();
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private:
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// Pointer to the patch we are writing to.
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PatchWriterInterface* patch_;
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// Old and new file buffers.
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const uint8_t* old_buf_;
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uint64_t old_size_;
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const uint8_t* new_buf_;
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uint64_t new_size_;
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// Bytes of the new_buf_ already written.
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uint64_t written_output_{0};
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// The current position in the old buf.
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int64_t old_pos_{0};
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};
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} // namespace bsdiff
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#endif // _BSDIFF_DIFF_ENCODER_H_
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