media/cast/net/rtp/packet_storage.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "media/cast/net/rtp/packet_storage.h"
   6
   7 #include "base/logging.h"
   8 #include "media/cast/cast_defines.h"
   9
  10 namespace media {
  11 namespace cast {
  12
  13 PacketStorage::PacketStorage()
  14     : first_frame_id_in_list_(0),
  15       zombie_count_(0) {
  16 }
  17
  18 PacketStorage::~PacketStorage() {
  19 }
  20
  21 size_t PacketStorage::GetNumberOfStoredFrames() const {
  22   return frames_.size() - zombie_count_;
  23 }
  24
  25 void PacketStorage::StoreFrame(uint32 frame_id,
  26                                const SendPacketVector& packets) {
  27   if (packets.empty()) {
  28     NOTREACHED();
  29     return;
  30   }
  31
  32   if (frames_.empty()) {
  33     first_frame_id_in_list_ = frame_id;
  34   } else {
  35     // Make sure frame IDs are consecutive.
  36     DCHECK_EQ(first_frame_id_in_list_ + static_cast<uint32>(frames_.size()),
  37               frame_id);
  38     // Make sure we aren't being asked to store more frames than the system's
  39     // design limit.
  40     DCHECK_LT(frames_.size(), static_cast<size_t>(kMaxUnackedFrames));
  41   }
  42
  43   // Save new frame to the end of the list.
  44   frames_.push_back(packets);
  45 }
  46
  47 void PacketStorage::ReleaseFrame(uint32 frame_id) {
  48   const uint32 offset = frame_id - first_frame_id_in_list_;
  49   if (static_cast<int32>(offset) < 0 || offset >= frames_.size() ||
  50       frames_[offset].empty()) {
  51     return;
  52   }
  53
  54   frames_[offset].clear();
  55   ++zombie_count_;
  56
  57   while (!frames_.empty() && frames_.front().empty()) {
  58     DCHECK_GT(zombie_count_, 0u);
  59     --zombie_count_;
  60     frames_.pop_front();
  61     ++first_frame_id_in_list_;
  62   }
  63 }
  64
  65 const SendPacketVector* PacketStorage::GetFrame8(uint8 frame_id_8bits) const {
  66   // The requested frame ID has only 8-bits so convert the first frame ID
  67   // in list to match.
  68   uint8 index_8bits = first_frame_id_in_list_ & 0xFF;
  69   index_8bits = frame_id_8bits - index_8bits;
  70   if (index_8bits >= frames_.size())
  71     return NULL;
  72   const SendPacketVector& packets = frames_[index_8bits];
  73   return packets.empty() ? NULL : &packets;
  74 }
  75
  76 }  // namespace cast
  77 }  // namespace media