50b1e6b760
Add code for delta-encoding and decoding, to be used when producing WebRTC event logs of the new format. This CL supports fixed-size encoding only. Also, no support for signed deltas or optional values yet. These will be added in subsequent CLs. Bug: webrtc:8111 Change-Id: I531abd99fd924f4c9e692abe565bc6f66c875ad5 Reviewed-on: https://webrtc-review.googlesource.com/c/100304 Reviewed-by: Björn Terelius <terelius@webrtc.org> Commit-Queue: Elad Alon <eladalon@webrtc.org> Cr-Commit-Position: refs/heads/master@{#25256}
40 lines
1.6 KiB
C++
40 lines
1.6 KiB
C++
/*
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* Copyright 2018 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef LOGGING_RTC_EVENT_LOG_ENCODER_DELTA_ENCODING_H_
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#define LOGGING_RTC_EVENT_LOG_ENCODER_DELTA_ENCODING_H_
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#include <string>
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#include <vector>
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namespace webrtc {
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// Encode |values| as a sequence of deltas following on |base| and return it.
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// If all of the values were equal to the base, an empty string will be
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// returned; this is a valid encoding of that edge case.
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// |base| is not guaranteed to be written into |output|, and must therefore
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// be provided separately to the decoder.
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// This function never fails.
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std::string EncodeDeltas(uint64_t base, const std::vector<uint64_t>& values);
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// EncodeDeltas() and DecodeDeltas() are inverse operations;
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// invoking DecodeDeltas() over the output of EncodeDeltas(), will return
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// the input originally given to EncodeDeltas().
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// |num_of_deltas| must be greater than zero. If input is not a valid encoding
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// of |num_of_deltas| elements based on |base|, the function returns an empty
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// vector, which signals an error.
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std::vector<uint64_t> DecodeDeltas(const std::string& input,
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uint64_t base,
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size_t num_of_deltas);
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} // namespace webrtc
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#endif // LOGGING_RTC_EVENT_LOG_ENCODER_DELTA_ENCODING_H_
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