/*

* SRT - Secure, Reliable, Transport

* Copyright (c) 2018 Haivision Systems Inc.

*

* This Source Code Form is subject to the terms of the Mozilla Public

* License, v. 2.0. If a copy of the MPL was not distributed with this

* file, You can obtain one at http://mozilla.org/MPL/2.0/.

*

*/

/*****************************************************************************

Copyright (c) 2001 - 2011, The Board of Trustees of the University of Illinois.

All rights reserved.

Redistribution and use in source and binary forms, with or without

modification, are permitted provided that the following conditions are

met:

* Redistributions of source code must retain the above

copyright notice, this list of conditions and the

following disclaimer.

* Redistributions in binary form must reproduce the

above copyright notice, this list of conditions

and the following disclaimer in the documentation

and/or other materials provided with the distribution.

* Neither the name of the University of Illinois

nor the names of its contributors may be used to

endorse or promote products derived from this

software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR

CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*****************************************************************************/

/*****************************************************************************

written by

Yunhong Gu, last updated 01/22/2011

modified by

Haivision Systems Inc.

*****************************************************************************/

#include "platform_sys.h"

#include <cmath>

#include <cstring>

#include "common.h"

#include "window.h"

#include <algorithm>

using namespace std;

using namespace srt::sync;

namespace srt

{

namespace ACKWindowTools

{

void store(Seq* r_aSeq, const size_t size, int& r_iHead, int& r_iTail, int32_t seq, int32_t ack)

{

r_aSeq[r_iHead].iACKSeqNo = seq;

r_aSeq[r_iHead].iACK = ack;

r_aSeq[r_iHead].tsTimeStamp = steady_clock::now();

r_iHead = (r_iHead + 1) % size;

// overwrite the oldest ACK since it is not likely to be acknowledged

if (r_iHead == r_iTail)

r_iTail = (r_iTail + 1) % size;

}

int acknowledge(Seq* r_aSeq, const size_t size, int& r_iHead, int& r_iTail, int32_t seq, int32_t& r_ack, const steady_clock::time_point& currtime)

{

// Head has not exceeded the physical boundary of the window

if (r_iHead >= r_iTail)

{

for (int i = r_iTail, n = r_iHead; i < n; ++ i)

{

// Looking for an identical ACK Seq. No.

if (seq == r_aSeq[i].iACKSeqNo)

{

// Return the Data ACK it carried

r_ack = r_aSeq[i].iACK;

// Calculate RTT estimate

const int rtt = (int)count_microseconds(currtime - r_aSeq[i].tsTimeStamp);

if (i + 1 == r_iHead)

{

r_iTail = r_iHead = 0;

r_aSeq[0].iACKSeqNo = SRT_SEQNO_NONE;

}

else

r_iTail = (i + 1) % size;

return rtt;

}

}

// The record about ACK is not found in the buffer, RTT can not be calculated

return -1;

}

// Head has exceeded the physical window boundary, so it is behind tail

for (int j = r_iTail, n = r_iHead + (int)size; j < n; ++ j)

{

// Looking for an identical ACK Seq. No.

if (seq == r_aSeq[j % size].iACKSeqNo)

{

// Return the Data ACK it carried

j %= size;

r_ack = r_aSeq[j].iACK;

// Calculate RTT estimate

const int rtt = (int)count_microseconds(currtime - r_aSeq[j].tsTimeStamp);

if (j == r_iHead)

{

r_iTail = r_iHead = 0;

r_aSeq[0].iACKSeqNo = -1;

}

else

r_iTail = (j + 1) % size;

return rtt;

}

}

// The record about ACK is not found in the buffer, RTT can not be calculated

return -1;

}

} // namespace AckTools

////////////////////////////////////////////////////////////////////////////////

void CPktTimeWindowTools::initializeWindowArrays(int* r_pktWindow, int* r_probeWindow, int* r_bytesWindow, size_t asize, size_t psize, size_t max_payload_size)

{

for (size_t i = 0; i < asize; ++ i)

r_pktWindow[i] = 1000000; //1 sec -> 1 pkt/sec

for (size_t k = 0; k < psize; ++ k)

r_probeWindow[k] = 1000; //1 msec -> 1000 pkts/sec

for (size_t i = 0; i < asize; ++ i)

r_bytesWindow[i] = int(max_payload_size); //based on 1 pkt/sec set in r_pktWindow[i]

}

int CPktTimeWindowTools::ceilPerMega(double value, double count)

{

static const double MEGA = 1000.0 * 1000.0;

return int(::ceil(MEGA / (value / count)));

}

int CPktTimeWindowTools::getPktRcvSpeed_in(const int* window, int* replica, const int* abytes, size_t asize, size_t hdr_size, int& w_bytesps)

{

PassFilter<int> filter = GetPeakRange(window, replica, asize);

unsigned count = 0;

int sum = 0;

w_bytesps = 0;

unsigned long bytes = 0;

AccumulatePassFilterParallel(window, asize, filter, abytes, (sum), (count), (bytes));

// calculate speed, or return 0 if not enough valid value

if (count <= (asize/2))

{

w_bytesps = 0;

return 0;

}

bytes += (unsigned long)(hdr_size * count); //Add protocol headers to bytes received

w_bytesps = ceilPerMega(sum, bytes);

return ceilPerMega(sum, count);

}

int CPktTimeWindowTools::getBandwidth_in(const int* window, int* replica, size_t psize)

{

PassFilter<int> filter = GetPeakRange(window, replica, psize);

int sum, count;

Tie(sum, count) = AccumulatePassFilter(window, psize, filter);

sum += filter.median;

count += 1;

return ceilPerMega(sum, count);

}

} // namespace srt