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      1 /*
      2  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #include <assert.h>
     12 #include <stdlib.h>
     13 #include "webrtc/modules/video_coding/main/source/timestamp_map.h"
     14 
     15 namespace webrtc {
     16 
     17 // Constructor. Optional parameter specifies maximum number of
     18 // coexisting timers.
     19 VCMTimestampMap::VCMTimestampMap(int32_t length):
     20     _nextAddIx(0),
     21     _nextPopIx(0)
     22 {
     23     if (length <= 0)
     24     {
     25         // default
     26         length = 10;
     27     }
     28 
     29     _map = new VCMTimestampDataTuple[length];
     30     _length = length;
     31 }
     32 
     33 // Destructor.
     34 VCMTimestampMap::~VCMTimestampMap()
     35 {
     36     delete [] _map;
     37 }
     38 
     39 // Empty the list of timers.
     40 void
     41 VCMTimestampMap::Reset()
     42 {
     43     _nextAddIx = 0;
     44     _nextPopIx = 0;
     45 }
     46 
     47 int32_t
     48 VCMTimestampMap::Add(uint32_t timestamp, void* data)
     49 {
     50     _map[_nextAddIx].timestamp = timestamp;
     51     _map[_nextAddIx].data = data;
     52     _nextAddIx = (_nextAddIx + 1) % _length;
     53 
     54     if (_nextAddIx == _nextPopIx)
     55     {
     56         // Circular list full; forget oldest entry
     57         _nextPopIx = (_nextPopIx + 1) % _length;
     58         return -1;
     59     }
     60     return 0;
     61 }
     62 
     63 void*
     64 VCMTimestampMap::Pop(uint32_t timestamp)
     65 {
     66     while (!IsEmpty())
     67     {
     68         if (_map[_nextPopIx].timestamp == timestamp)
     69         {
     70             // found start time for this timestamp
     71             void* data = _map[_nextPopIx].data;
     72             _map[_nextPopIx].data = NULL;
     73             _nextPopIx = (_nextPopIx + 1) % _length;
     74             return data;
     75         }
     76         else if (_map[_nextPopIx].timestamp > timestamp)
     77         {
     78             // the timestamp we are looking for is not in the list
     79             assert(_nextPopIx < _length && _nextPopIx >= 0);
     80             return NULL;
     81         }
     82 
     83         // not in this position, check next (and forget this position)
     84         _nextPopIx = (_nextPopIx + 1) % _length;
     85     }
     86 
     87     // could not find matching timestamp in list
     88     assert(_nextPopIx < _length && _nextPopIx >= 0);
     89     return NULL;
     90 }
     91 
     92 // Check if no timers are currently running
     93 bool
     94 VCMTimestampMap::IsEmpty() const
     95 {
     96     return (_nextAddIx == _nextPopIx);
     97 }
     98 
     99 }
    100