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Issue 992733002: Remove //net (except for Android test stuff) and sdch (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: Created 5 years, 9 months ago
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1 // Copyright (c) 2012 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 "net/quic/quic_fec_group.h"
6
7 #include <limits>
8
9 #include "base/basictypes.h"
10 #include "base/logging.h"
11 #include "base/stl_util.h"
12
13 using base::StringPiece;
14 using std::numeric_limits;
15 using std::set;
16
17 namespace net {
18
19 namespace {
20 const QuicPacketSequenceNumber kNoSequenceNumber = kuint64max;
21 } // namespace
22
23 QuicFecGroup::QuicFecGroup()
24 : min_protected_packet_(kNoSequenceNumber),
25 max_protected_packet_(kNoSequenceNumber),
26 payload_parity_len_(0),
27 effective_encryption_level_(NUM_ENCRYPTION_LEVELS) {
28 }
29
30 QuicFecGroup::~QuicFecGroup() {}
31
32 bool QuicFecGroup::Update(EncryptionLevel encryption_level,
33 const QuicPacketHeader& header,
34 StringPiece decrypted_payload) {
35 if (ContainsKey(received_packets_, header.packet_sequence_number)) {
36 return false;
37 }
38 if (min_protected_packet_ != kNoSequenceNumber &&
39 max_protected_packet_ != kNoSequenceNumber &&
40 (header.packet_sequence_number < min_protected_packet_ ||
41 header.packet_sequence_number > max_protected_packet_)) {
42 DLOG(ERROR) << "FEC group does not cover received packet: "
43 << header.packet_sequence_number;
44 return false;
45 }
46 if (!UpdateParity(decrypted_payload)) {
47 return false;
48 }
49 received_packets_.insert(header.packet_sequence_number);
50 if (encryption_level < effective_encryption_level_) {
51 effective_encryption_level_ = encryption_level;
52 }
53 return true;
54 }
55
56 bool QuicFecGroup::UpdateFec(
57 EncryptionLevel encryption_level,
58 QuicPacketSequenceNumber fec_packet_sequence_number,
59 const QuicFecData& fec) {
60 if (min_protected_packet_ != kNoSequenceNumber) {
61 return false;
62 }
63 SequenceNumberSet::const_iterator it = received_packets_.begin();
64 while (it != received_packets_.end()) {
65 if ((*it < fec.fec_group) || (*it >= fec_packet_sequence_number)) {
66 DLOG(ERROR) << "FEC group does not cover received packet: " << *it;
67 return false;
68 }
69 ++it;
70 }
71 if (!UpdateParity(fec.redundancy)) {
72 return false;
73 }
74 min_protected_packet_ = fec.fec_group;
75 max_protected_packet_ = fec_packet_sequence_number - 1;
76 if (encryption_level < effective_encryption_level_) {
77 effective_encryption_level_ = encryption_level;
78 }
79 return true;
80 }
81
82 bool QuicFecGroup::CanRevive() const {
83 // We can revive if we're missing exactly 1 packet.
84 return NumMissingPackets() == 1;
85 }
86
87 bool QuicFecGroup::IsFinished() const {
88 // We are finished if we are not missing any packets.
89 return NumMissingPackets() == 0;
90 }
91
92 size_t QuicFecGroup::Revive(QuicPacketHeader* header,
93 char* decrypted_payload,
94 size_t decrypted_payload_len) {
95 if (!CanRevive()) {
96 return 0;
97 }
98
99 // Identify the packet sequence number to be resurrected.
100 QuicPacketSequenceNumber missing = kNoSequenceNumber;
101 for (QuicPacketSequenceNumber i = min_protected_packet_;
102 i <= max_protected_packet_; ++i) {
103 // Is this packet missing?
104 if (received_packets_.count(i) == 0) {
105 missing = i;
106 break;
107 }
108 }
109 DCHECK_NE(kNoSequenceNumber, missing);
110
111 DCHECK_LE(payload_parity_len_, decrypted_payload_len);
112 if (payload_parity_len_ > decrypted_payload_len) {
113 return 0;
114 }
115 for (size_t i = 0; i < payload_parity_len_; ++i) {
116 decrypted_payload[i] = payload_parity_[i];
117 }
118
119 header->packet_sequence_number = missing;
120 header->entropy_flag = false; // Unknown entropy.
121
122 received_packets_.insert(missing);
123 return payload_parity_len_;
124 }
125
126 bool QuicFecGroup::ProtectsPacketsBefore(QuicPacketSequenceNumber num) const {
127 if (max_protected_packet_ != kNoSequenceNumber) {
128 return max_protected_packet_ < num;
129 }
130 // Since we might not yet have received the FEC packet, we must check
131 // the packets we have received.
132 return *received_packets_.begin() < num;
133 }
134
135 bool QuicFecGroup::UpdateParity(StringPiece payload) {
136 DCHECK_LE(payload.size(), kMaxPacketSize);
137 if (payload.size() > kMaxPacketSize) {
138 DLOG(ERROR) << "Illegal payload size: " << payload.size();
139 return false;
140 }
141 if (payload_parity_len_ < payload.size()) {
142 payload_parity_len_ = payload.size();
143 }
144 DCHECK_LE(payload.size(), kMaxPacketSize);
145 if (received_packets_.empty() &&
146 min_protected_packet_ == kNoSequenceNumber) {
147 // Initialize the parity to the value of this payload
148 memcpy(payload_parity_, payload.data(), payload.size());
149 if (payload.size() < kMaxPacketSize) {
150 // TODO(rch): expand as needed.
151 memset(payload_parity_ + payload.size(), 0,
152 kMaxPacketSize - payload.size());
153 }
154 return true;
155 }
156 // Update the parity by XORing in the data (padding with 0s if necessary).
157 for (size_t i = 0; i < kMaxPacketSize; ++i) {
158 uint8 byte = i < payload.size() ? payload[i] : 0x00;
159 payload_parity_[i] ^= byte;
160 }
161 return true;
162 }
163
164 size_t QuicFecGroup::NumMissingPackets() const {
165 if (min_protected_packet_ == kNoSequenceNumber)
166 return numeric_limits<size_t>::max();
167 return static_cast<size_t>(
168 (max_protected_packet_ - min_protected_packet_ + 1) -
169 received_packets_.size());
170 }
171
172 } // namespace net
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