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// Copyright 2017 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef _BSDIFF_PATCH_READER_H_
#define _BSDIFF_PATCH_READER_H_
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include "bsdiff/control_entry.h"
#include "bsdiff/decompressor_interface.h"
#include "bsdiff/file_interface.h"
namespace bsdiff {
// A wrapper class to read and parse the data in a bsdiff patch. The reader
// class contains the concatenated streams of control, diff, and extra data.
// After initialization, this class provides the function to read the metadata
// embedded in the control stream sequentially and decompresses the diff & extra
// stream based on this metadata.
class BsdiffPatchReader {
public:
BsdiffPatchReader() = default;
// Initialize the control stream, diff stream and extra stream from the
// corresponding offset of |patch_data|.
bool Init(const uint8_t* patch_data, size_t patch_size);
// Read the control stream and parse the metadata of |diff_size_|,
// |extra_size_| and |offset_incremental_|.
bool ParseControlEntry(ControlEntry* control_entry);
// Read the data in |diff_stream_| and write |size| decompressed data to
// |buf|.
bool ReadDiffStream(uint8_t* buf, size_t size);
// Read the data in |extra_stream_| and write |size| decompressed data to
// |buf|.
bool ReadExtraStream(uint8_t* buf, size_t size);
uint64_t new_file_size() const { return new_file_size_; }
// Close the control/diff/extra stream. Return false if errors occur when
// closing any of these streams.
bool Finish();
private:
// The compressed stream that contains the control data; i.e. length of each
// diff/extra block and the corresponding offset to read in the source file.
std::unique_ptr<DecompressorInterface> ctrl_stream_{nullptr};
// The compressed stream that contains the concatenated diff blocks.
std::unique_ptr<DecompressorInterface> diff_stream_{nullptr};
// The compressed stream that contains the concatenated extra blocks.
std::unique_ptr<DecompressorInterface> extra_stream_{nullptr};
// Size of the target file.
uint64_t new_file_size_;
};
} // namespace bsdiff
#endif // _BSDIFF_PATCH_READER_H_
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