257ed437f0
Optional fields are those which only occur sometimes. For example, the sequence number field in an RTP packet always occurs, but fields in optional RTP extensions only occur sometimes. Bug: webrtc:8111 Change-Id: Iff2c35b73530c0a1db68e547b4caf34434aa4ace Reviewed-on: https://webrtc-review.googlesource.com/c/103362 Commit-Queue: Elad Alon <eladalon@webrtc.org> Reviewed-by: Björn Terelius <terelius@webrtc.org> Cr-Commit-Position: refs/heads/master@{#25336}
46 lines
1.8 KiB
C++
46 lines
1.8 KiB
C++
/*
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* Copyright (c) 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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#include "absl/types/optional.h"
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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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// TODO(eladalon): Split into optional and non-optional variants (efficiency).
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std::string EncodeDeltas(absl::optional<uint64_t> base,
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const std::vector<absl::optional<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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// TODO(eladalon): Split into optional and non-optional variants (efficiency).
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std::vector<absl::optional<uint64_t>> DecodeDeltas(
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const std::string& input,
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absl::optional<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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