webrtc/modules/video_coding/main/source/timestamp_map.cc

100 lines
2.3 KiB
C++

/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "timestamp_map.h"
#include <stdlib.h>
#include <assert.h>
namespace webrtc {
// Constructor. Optional parameter specifies maximum number of
// coexisting timers.
VCMTimestampMap::VCMTimestampMap(WebRtc_Word32 length):
_nextAddIx(0),
_nextPopIx(0)
{
if (length <= 0)
{
// default
length = 10;
}
_map = new VCMTimestampDataTuple[length];
_length = length;
}
// Destructor.
VCMTimestampMap::~VCMTimestampMap()
{
delete [] _map;
}
// Empty the list of timers.
void
VCMTimestampMap::Reset()
{
_nextAddIx = 0;
_nextPopIx = 0;
}
WebRtc_Word32
VCMTimestampMap::Add(WebRtc_UWord32 timestamp, void* data)
{
_map[_nextAddIx].timestamp = timestamp;
_map[_nextAddIx].data = data;
_nextAddIx = (_nextAddIx + 1) % _length;
if (_nextAddIx == _nextPopIx)
{
// Circular list full; forget oldest entry
_nextPopIx = (_nextPopIx + 1) % _length;
return -1;
}
return 0;
}
void*
VCMTimestampMap::Pop(WebRtc_UWord32 timestamp)
{
while (!IsEmpty())
{
if (_map[_nextPopIx].timestamp == timestamp)
{
// found start time for this timestamp
void* data = _map[_nextPopIx].data;
_map[_nextPopIx].data = NULL;
_nextPopIx = (_nextPopIx + 1) % _length;
return data;
}
else if (_map[_nextPopIx].timestamp > timestamp)
{
// the timestamp we are looking for is not in the list
assert(_nextPopIx < _length && _nextPopIx >= 0);
return NULL;
}
// not in this position, check next (and forget this position)
_nextPopIx = (_nextPopIx + 1) % _length;
}
// could not find matching timestamp in list
assert(_nextPopIx < _length && _nextPopIx >= 0);
return NULL;
}
// Check if no timers are currently running
bool
VCMTimestampMap::IsEmpty() const
{
return (_nextAddIx == _nextPopIx);
}
}