43 lines
1.3 KiB
C++
43 lines
1.3 KiB
C++
// Copyright 2014 Google Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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#ifndef MPD_BASE_BANDWIDTH_ESTIMATOR_H_
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#define MPD_BASE_BANDWIDTH_ESTIMATOR_H_
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#include <list>
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#include "base/basictypes.h"
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class BandwidthEstimator {
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public:
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/// @param num_blocks is the number of latest blocks to use. Negative values
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/// use first N blocks. 0 uses all.
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explicit BandwidthEstimator(int num_blocks);
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~BandwidthEstimator();
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// @param size is the size of the block in bytes. Should be positive.
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// @param duration is the length in seconds. Should be positive.
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void AddBlock(uint64 size, double duration);
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// @return The estimate bandwidth, in bits per second, from the harmonic mean
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// of the number of blocks specified in the constructor. The value is
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// rounded up to the nearest integer.
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uint64 Estimate() const;
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static const int kUseAllBlocks;
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private:
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const int num_blocks_for_estimation_;
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double harmonic_mean_denominator_;
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// This is not used when num_blocks_for_estimation_ != 0. Therefore it should
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// always be 0 if num_blocks_for_estimation_ != 0.
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size_t num_blocks_added_;
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std::list<double> history_;
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};
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#endif // MPD_BASE_BANDWIDTH_ESTIMATOR_H_
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