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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/cast/rtp_sender/packet_storage/packet_storage.h"
#include <string>
#include "base/logging.h"
#include "media/cast/cast_defines.h"
namespace media {
namespace cast {
// Limit the max time delay to avoid frame id wrap around; 256 / 60 fps.
const int kMaxAllowedTimeStoredMs = 4000;
typedef PacketMap::iterator PacketMapIterator;
typedef TimeToPacketMap::iterator TimeToPacketIterator;
class StoredPacket {
public:
StoredPacket() {
packet_.reserve(kIpPacketSize);
}
void Save(const Packet* packet) {
DCHECK_LT(packet->size(), kIpPacketSize) << "Invalid argument";
packet_.clear();
packet_.insert(packet_.begin(), packet->begin(), packet->end());
}
void GetCopy(PacketList* packets) {
packets->push_back(Packet(packet_.begin(), packet_.end()));
}
private:
Packet packet_;
};
PacketStorage::PacketStorage(base::TickClock* clock,
int max_time_stored_ms)
: clock_(clock) {
max_time_stored_ = base::TimeDelta::FromMilliseconds(max_time_stored_ms);
DCHECK_LE(max_time_stored_ms, kMaxAllowedTimeStoredMs) << "Invalid argument";
}
PacketStorage::~PacketStorage() {
time_to_packet_map_.clear();
PacketMapIterator store_it = stored_packets_.begin();
for (; store_it != stored_packets_.end();
store_it = stored_packets_.begin()) {
stored_packets_.erase(store_it);
}
while (!free_packets_.empty()) {
free_packets_.pop_front();
}
}
void PacketStorage::CleanupOldPackets(base::TimeTicks now) {
TimeToPacketIterator time_it = time_to_packet_map_.begin();
// Check max size.
while (time_to_packet_map_.size() >= kMaxStoredPackets) {
PacketMapIterator store_it = stored_packets_.find(time_it->second);
// We should always find the packet.
DCHECK(store_it != stored_packets_.end()) << "Invalid state";
time_to_packet_map_.erase(time_it);
// Save the pointer.
linked_ptr<StoredPacket> storted_packet = store_it->second;
stored_packets_.erase(store_it);
// Add this packet to the free list for later re-use.
free_packets_.push_back(storted_packet);
time_it = time_to_packet_map_.begin();
}
// Time out old packets.
while (time_it != time_to_packet_map_.end()) {
if (now < time_it->first + max_time_stored_) {
break;
}
// Packet too old.
PacketMapIterator store_it = stored_packets_.find(time_it->second);
// We should always find the packet.
DCHECK(store_it != stored_packets_.end()) << "Invalid state";
time_to_packet_map_.erase(time_it);
// Save the pointer.
linked_ptr<StoredPacket> storted_packet = store_it->second;
stored_packets_.erase(store_it);
// Add this packet to the free list for later re-use.
free_packets_.push_back(storted_packet);
time_it = time_to_packet_map_.begin();
}
}
void PacketStorage::StorePacket(uint32 frame_id, uint16 packet_id,
const Packet* packet) {
base::TimeTicks now = clock_->NowTicks();
CleanupOldPackets(now);
// Internally we only use the 8 LSB of the frame id.
uint32 index = ((0xff & frame_id) << 16) + packet_id;
PacketMapIterator it = stored_packets_.find(index);
if (it != stored_packets_.end()) {
// We have already saved this.
DCHECK(false) << "Invalid state";
return;
}
linked_ptr<StoredPacket> stored_packet;
if (free_packets_.empty()) {
// No previous allocated packets allocate one.
stored_packet.reset(new StoredPacket());
} else {
// Re-use previous allocated packet.
stored_packet = free_packets_.front();
free_packets_.pop_front();
}
stored_packet->Save(packet);
stored_packets_[index] = stored_packet;
time_to_packet_map_.insert(std::make_pair(now, index));
}
PacketList PacketStorage::GetPackets(
const MissingFramesAndPacketsMap& missing_frames_and_packets) {
PacketList packets_to_resend;
// Iterate over all frames in the list.
for (MissingFramesAndPacketsMap::const_iterator it =
missing_frames_and_packets.begin();
it != missing_frames_and_packets.end(); ++it) {
uint8 frame_id = it->first;
const PacketIdSet& packets_set = it->second;
bool success = false;
if (packets_set.empty()) {
VLOG(1) << "Missing all packets in frame " << static_cast<int>(frame_id);
uint16 packet_id = 0;
do {
// Get packet from storage.
success = GetPacket(frame_id, packet_id, &packets_to_resend);
++packet_id;
} while (success);
} else {
// Iterate over all of the packets in the frame.
for (PacketIdSet::const_iterator set_it = packets_set.begin();
set_it != packets_set.end(); ++set_it) {
GetPacket(frame_id, *set_it, &packets_to_resend);
}
}
}
return packets_to_resend;
}
bool PacketStorage::GetPacket(uint8 frame_id,
uint16 packet_id,
PacketList* packets) {
// Internally we only use the 8 LSB of the frame id.
uint32 index = (static_cast<uint32>(frame_id) << 16) + packet_id;
PacketMapIterator it = stored_packets_.find(index);
if (it == stored_packets_.end()) {
return false;
}
it->second->GetCopy(packets);
VLOG(1) << "Resend " << static_cast<int>(frame_id)
<< ":" << packet_id;
return true;
}
} // namespace cast
} // namespace media
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