rtcp::Dlrr block moved into own file and got Parse function

BUG=webrtc:5260

Review URL: https://codereview.webrtc.org/1453973005

Cr-Commit-Position: refs/heads/master@{#11044}

8 files changed, 280 insertions, 105 deletions

diff --git a/webrtc/modules/modules.gyp b/webrtc/modules/modules.gyp
index f58e0f4034..0dec33749d 100644
--- a/webrtc/modules/modules.gyp
+++ b/webrtc/modules/modules.gyp
@@ -306,6 +306,7 @@
                 'rtp_rtcp/source/rtcp_packet_unittest.cc',
                 'rtp_rtcp/source/rtcp_packet/app_unittest.cc',
                 'rtp_rtcp/source/rtcp_packet/bye_unittest.cc',
+                'rtp_rtcp/source/rtcp_packet/dlrr_unittest.cc',
                 'rtp_rtcp/source/rtcp_packet/extended_jitter_report_unittest.cc',
                 'rtp_rtcp/source/rtcp_packet/pli_unittest.cc',
                 'rtp_rtcp/source/rtcp_packet/receiver_report_unittest.cc',
diff --git a/webrtc/modules/rtp_rtcp/BUILD.gn b/webrtc/modules/rtp_rtcp/BUILD.gn
index be6e2e4c7d..aa2e9c5800 100644
--- a/webrtc/modules/rtp_rtcp/BUILD.gn
+++ b/webrtc/modules/rtp_rtcp/BUILD.gn
@@ -50,6 +50,8 @@ source_set("rtp_rtcp") {
     "source/rtcp_packet/app.h",
     "source/rtcp_packet/bye.cc",
     "source/rtcp_packet/bye.h",
+    "source/rtcp_packet/dlrr.cc",
+    "source/rtcp_packet/dlrr.h",
     "source/rtcp_packet/extended_jitter_report.cc",
     "source/rtcp_packet/extended_jitter_report.h",
     "source/rtcp_packet/pli.cc",
diff --git a/webrtc/modules/rtp_rtcp/rtp_rtcp.gypi b/webrtc/modules/rtp_rtcp/rtp_rtcp.gypi
index 1b88055695..98b2659c94 100644
--- a/webrtc/modules/rtp_rtcp/rtp_rtcp.gypi
+++ b/webrtc/modules/rtp_rtcp/rtp_rtcp.gypi
@@ -45,6 +45,8 @@
         'source/rtcp_packet/app.h',
         'source/rtcp_packet/bye.cc',
         'source/rtcp_packet/bye.h',
+        'source/rtcp_packet/dlrr.cc',
+        'source/rtcp_packet/dlrr.h',
         'source/rtcp_packet/extended_jitter_report.cc',
         'source/rtcp_packet/extended_jitter_report.h',
         'source/rtcp_packet/pli.cc',
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_packet.cc b/webrtc/modules/rtp_rtcp/source/rtcp_packet.cc
index 28cb20eca2..1508658f5d 100644
--- a/webrtc/modules/rtp_rtcp/source/rtcp_packet.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_packet.cc
@@ -407,50 +407,6 @@ void CreateXrHeader(const RTCPPacketXR& header,
   AssignUWord32(buffer, pos, header.OriginatorSSRC);
 }
 
-void CreateXrBlockHeader(uint8_t block_type,
-                         uint16_t block_length,
-                         uint8_t* buffer,
-                         size_t* pos) {
-  AssignUWord8(buffer, pos, block_type);
-  AssignUWord8(buffer, pos, 0);
-  AssignUWord16(buffer, pos, block_length);
-}
-
-// DLRR Report Block (RFC 3611).
-//
-//   0                   1                   2                   3
-//   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-//  |     BT=5      |   reserved    |         block length          |
-//  +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
-//  |                 SSRC_1 (SSRC of first receiver)               | sub-
-//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
-//  |                         last RR (LRR)                         |   1
-//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-//  |                   delay since last RR (DLRR)                  |
-//  +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
-//  |                 SSRC_2 (SSRC of second receiver)              | sub-
-//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
-//  :                               ...                             :   2
-
-void CreateDlrr(const std::vector<Xr::DlrrBlock>& dlrrs,
-                uint8_t* buffer,
-                size_t* pos) {
-  for (std::vector<Xr::DlrrBlock>::const_iterator it = dlrrs.begin();
-       it != dlrrs.end(); ++it) {
-    if ((*it).empty()) {
-      continue;
-    }
-    uint16_t block_length = 3 * (*it).size();
-    CreateXrBlockHeader(kBtDlrr, block_length, buffer, pos);
-    for (Xr::DlrrBlock::const_iterator it_block = (*it).begin();
-         it_block != (*it).end(); ++it_block) {
-      AssignUWord32(buffer, pos, (*it_block).SSRC);
-      AssignUWord32(buffer, pos, (*it_block).LastRR);
-      AssignUWord32(buffer, pos, (*it_block).DelayLastRR);
-    }
-  }
-}
 }  // namespace
 
 void RtcpPacket::Append(RtcpPacket* packet) {
@@ -834,7 +790,10 @@ bool Xr::Create(uint8_t* packet,
     block.Create(packet + *index);
     *index += Rrtr::kLength;
   }
-  CreateDlrr(dlrr_blocks_, packet, index);
+  for (const Dlrr& block : dlrr_blocks_) {
+    block.Create(packet + *index);
+    *index += block.BlockLength();
+  }
   for (const VoipMetric& block : voip_metric_blocks_) {
     block.Create(packet + *index);
     *index += VoipMetric::kLength;
@@ -853,12 +812,12 @@ bool Xr::WithRrtr(Rrtr* rrtr) {
 }
 
 bool Xr::WithDlrr(Dlrr* dlrr) {
-  assert(dlrr);
+  RTC_DCHECK(dlrr);
   if (dlrr_blocks_.size() >= kMaxNumberOfDlrrBlocks) {
     LOG(LS_WARNING) << "Max DLRR blocks reached.";
     return false;
   }
-  dlrr_blocks_.push_back(dlrr->dlrr_block_);
+  dlrr_blocks_.push_back(*dlrr);
   return true;
 }
 
@@ -873,33 +832,13 @@ bool Xr::WithVoipMetric(VoipMetric* voip_metric) {
 }
 
 size_t Xr::DlrrLength() const {
-  const size_t kBlockHeaderLen = 4;
-  const size_t kSubBlockLen = 12;
   size_t length = 0;
-  for (std::vector<DlrrBlock>::const_iterator it = dlrr_blocks_.begin();
-       it != dlrr_blocks_.end(); ++it) {
-    if (!(*it).empty()) {
-      length += kBlockHeaderLen + kSubBlockLen * (*it).size();
-    }
+  for (const Dlrr& block : dlrr_blocks_) {
+    length += block.BlockLength();
   }
   return length;
 }
 
-bool Dlrr::WithDlrrItem(uint32_t ssrc,
-                        uint32_t last_rr,
-                        uint32_t delay_last_rr) {
-  if (dlrr_block_.size() >= kMaxNumberOfDlrrItems) {
-    LOG(LS_WARNING) << "Max DLRR items reached.";
-    return false;
-  }
-  RTCPPacketXRDLRRReportBlockItem dlrr;
-  dlrr.SSRC = ssrc;
-  dlrr.LastRR = last_rr;
-  dlrr.DelayLastRR = delay_last_rr;
-  dlrr_block_.push_back(dlrr);
-  return true;
-}
-
 RawPacket::RawPacket(size_t buffer_length)
     : buffer_length_(buffer_length), length_(0) {
   buffer_.reset(new uint8_t[buffer_length]);
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_packet.h b/webrtc/modules/rtp_rtcp/source/rtcp_packet.h
index dcbb1e72d3..3adcc9a759 100644
--- a/webrtc/modules/rtp_rtcp/source/rtcp_packet.h
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_packet.h
@@ -18,6 +18,7 @@
 
 #include "webrtc/base/scoped_ptr.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/report_block.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/rrtr.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/voip_metric.h"
@@ -30,7 +31,6 @@ namespace rtcp {
 static const int kCommonFbFmtLength = 12;
 static const int kReportBlockLength = 24;
 
-class Dlrr;
 class RawPacket;
 
 // Class for building RTCP packets.
@@ -679,46 +679,12 @@ class Xr : public RtcpPacket {
 
   RTCPUtility::RTCPPacketXR xr_header_;
   std::vector<Rrtr> rrtr_blocks_;
-  std::vector<DlrrBlock> dlrr_blocks_;
+  std::vector<Dlrr> dlrr_blocks_;
   std::vector<VoipMetric> voip_metric_blocks_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(Xr);
 };
 
-// DLRR Report Block (RFC 3611).
-//
-//   0                   1                   2                   3
-//   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-//  |     BT=5      |   reserved    |         block length          |
-//  +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
-//  |                 SSRC_1 (SSRC of first receiver)               | sub-
-//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
-//  |                         last RR (LRR)                         |   1
-//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-//  |                   delay since last RR (DLRR)                  |
-//  +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
-//  |                 SSRC_2 (SSRC of second receiver)              | sub-
-//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
-//  :                               ...                             :   2
-
-class Dlrr {
- public:
-  Dlrr() {}
-  ~Dlrr() {}
-
-  // Max 100 DLRR Items can be added per DLRR report block.
-  bool WithDlrrItem(uint32_t ssrc, uint32_t last_rr, uint32_t delay_last_rr);
-
- private:
-  friend class Xr;
-  static const int kMaxNumberOfDlrrItems = 100;
-
-  std::vector<RTCPUtility::RTCPPacketXRDLRRReportBlockItem> dlrr_block_;
-
-  RTC_DISALLOW_COPY_AND_ASSIGN(Dlrr);
-};
-
 // Class holding a RTCP packet.
 //
 // Takes a built rtcp packet.
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr.cc b/webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr.cc
new file mode 100644
index 0000000000..6d6c48fada
--- /dev/null
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr.cc
@@ -0,0 +1,100 @@
+/*
+ *  Copyright (c) 2015 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 "webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr.h"
+
+#include "webrtc/base/checks.h"
+#include "webrtc/base/logging.h"
+#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
+
+namespace webrtc {
+namespace rtcp {
+// DLRR Report Block (RFC 3611).
+//
+//   0                   1                   2                   3
+//   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//  |     BT=5      |   reserved    |         block length          |
+//  +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
+//  |                 SSRC_1 (SSRC of first receiver)               | sub-
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
+//  |                         last RR (LRR)                         |   1
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//  |                   delay since last RR (DLRR)                  |
+//  +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
+//  |                 SSRC_2 (SSRC of second receiver)              | sub-
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
+//  :                               ...                             :   2
+bool Dlrr::Parse(const uint8_t* buffer, uint16_t block_length_32bits) {
+  RTC_DCHECK(buffer[0] == kBlockType);
+  // kReserved = buffer[1];
+  RTC_DCHECK_EQ(block_length_32bits,
+                ByteReader<uint16_t>::ReadBigEndian(&buffer[2]));
+  if (block_length_32bits % 3 != 0) {
+    LOG(LS_WARNING) << "Invalid size for dlrr block.";
+    return false;
+  }
+
+  size_t blocks_count = block_length_32bits / 3;
+  const uint8_t* read_at = buffer + kBlockHeaderLength;
+  sub_blocks_.resize(blocks_count);
+  for (SubBlock& sub_block : sub_blocks_) {
+    sub_block.ssrc = ByteReader<uint32_t>::ReadBigEndian(&read_at[0]);
+    sub_block.last_rr = ByteReader<uint32_t>::ReadBigEndian(&read_at[4]);
+    sub_block.delay_since_last_rr =
+        ByteReader<uint32_t>::ReadBigEndian(&read_at[8]);
+    read_at += kSubBlockLength;
+  }
+  return true;
+}
+
+size_t Dlrr::BlockLength() const {
+  if (sub_blocks_.empty())
+    return 0;
+  return kBlockHeaderLength + kSubBlockLength * sub_blocks_.size();
+}
+
+void Dlrr::Create(uint8_t* buffer) const {
+  if (sub_blocks_.empty())  // No subblocks, no need to write header either.
+    return;
+  // Create block header.
+  const uint8_t kReserved = 0;
+  buffer[0] = kBlockType;
+  buffer[1] = kReserved;
+  ByteWriter<uint16_t>::WriteBigEndian(&buffer[2], 3 * sub_blocks_.size());
+  // Create sub blocks.
+  uint8_t* write_at = buffer + kBlockHeaderLength;
+  for (const SubBlock& sub_block : sub_blocks_) {
+    ByteWriter<uint32_t>::WriteBigEndian(&write_at[0], sub_block.ssrc);
+    ByteWriter<uint32_t>::WriteBigEndian(&write_at[4], sub_block.last_rr);
+    ByteWriter<uint32_t>::WriteBigEndian(&write_at[8],
+                                         sub_block.delay_since_last_rr);
+    write_at += kSubBlockLength;
+  }
+  RTC_DCHECK_EQ(buffer + BlockLength(), write_at);
+}
+
+bool Dlrr::WithDlrrItem(uint32_t ssrc,
+                        uint32_t last_rr,
+                        uint32_t delay_last_rr) {
+  if (sub_blocks_.size() >= kMaxNumberOfDlrrItems) {
+    LOG(LS_WARNING) << "Max DLRR items reached.";
+    return false;
+  }
+  SubBlock block;
+  block.ssrc = ssrc;
+  block.last_rr = last_rr;
+  block.delay_since_last_rr = delay_last_rr;
+  sub_blocks_.push_back(block);
+  return true;
+}
+
+}  // namespace rtcp
+}  // namespace webrtc
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr.h b/webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr.h
new file mode 100644
index 0000000000..9af2dedf3f
--- /dev/null
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr.h
@@ -0,0 +1,63 @@
+/*
+ *  Copyright (c) 2015 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.
+ *
+ */
+
+#ifndef WEBRTC_MODULES_RTP_RTCP_SOURCE_RTCP_PACKET_DLRR_H_
+#define WEBRTC_MODULES_RTP_RTCP_SOURCE_RTCP_PACKET_DLRR_H_
+
+#include <vector>
+
+#include "webrtc/base/basictypes.h"
+
+namespace webrtc {
+namespace rtcp {
+
+// DLRR Report Block: Delay since the Last Receiver Report (RFC 3611).
+class Dlrr {
+ public:
+  struct SubBlock {
+    // RFC 3611 4.5
+    uint32_t ssrc;
+    uint32_t last_rr;
+    uint32_t delay_since_last_rr;
+  };
+
+  static const uint8_t kBlockType = 5;
+  static const size_t kMaxNumberOfDlrrItems = 100;
+
+  Dlrr() {}
+  Dlrr(const Dlrr& other) = default;
+  ~Dlrr() {}
+
+  Dlrr& operator=(const Dlrr& other) = default;
+
+  // Second parameter is value read from block header,
+  // i.e. size of block in 32bits excluding block header itself.
+  bool Parse(const uint8_t* buffer, uint16_t block_length_32bits);
+
+  size_t BlockLength() const;
+  // Fills buffer with the Dlrr.
+  // Consumes BlockLength() bytes.
+  void Create(uint8_t* buffer) const;
+
+  // Max 100 DLRR Items can be added per DLRR report block.
+  bool WithDlrrItem(uint32_t ssrc, uint32_t last_rr, uint32_t delay_last_rr);
+
+  const std::vector<SubBlock>& sub_blocks() const { return sub_blocks_; }
+
+ private:
+  static const size_t kBlockHeaderLength = 4;
+  static const size_t kSubBlockLength = 12;
+
+  std::vector<SubBlock> sub_blocks_;
+};
+}  // namespace rtcp
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_RTCP_PACKET_DLRR_H_
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr_unittest.cc
new file mode 100644
index 0000000000..c7c139c560
--- /dev/null
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr_unittest.cc
@@ -0,0 +1,102 @@
+/*
+ *  Copyright (c) 2015 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 "webrtc/modules/rtp_rtcp/source/rtcp_packet/dlrr.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
+
+using webrtc::rtcp::Dlrr;
+
+namespace webrtc {
+namespace {
+
+const uint32_t kSsrc = 0x12345678;
+const uint32_t kLastRR = 0x23344556;
+const uint32_t kDelay = 0x33343536;
+const uint8_t kBlock[] = {0x05, 0x00, 0x00, 0x03, 0x12, 0x34, 0x56, 0x78,
+                          0x23, 0x34, 0x45, 0x56, 0x33, 0x34, 0x35, 0x36};
+const size_t kBlockSizeBytes = sizeof(kBlock);
+
+TEST(RtcpPacketDlrrTest, Empty) {
+  Dlrr dlrr;
+
+  EXPECT_EQ(0u, dlrr.BlockLength());
+}
+
+TEST(RtcpPacketDlrrTest, Create) {
+  Dlrr dlrr;
+  EXPECT_TRUE(dlrr.WithDlrrItem(kSsrc, kLastRR, kDelay));
+
+  ASSERT_EQ(kBlockSizeBytes, dlrr.BlockLength());
+  uint8_t buffer[kBlockSizeBytes];
+
+  dlrr.Create(buffer);
+  EXPECT_EQ(0, memcmp(buffer, kBlock, kBlockSizeBytes));
+}
+
+TEST(RtcpPacketDlrrTest, Parse) {
+  Dlrr dlrr;
+  uint16_t block_length = ByteReader<uint16_t>::ReadBigEndian(&kBlock[2]);
+  EXPECT_TRUE(dlrr.Parse(kBlock, block_length));
+
+  EXPECT_EQ(1u, dlrr.sub_blocks().size());
+  const Dlrr::SubBlock& block = dlrr.sub_blocks().front();
+  EXPECT_EQ(kSsrc, block.ssrc);
+  EXPECT_EQ(kLastRR, block.last_rr);
+  EXPECT_EQ(kDelay, block.delay_since_last_rr);
+}
+
+TEST(RtcpPacketDlrrTest, ParseFailsOnBadSize) {
+  const size_t kBigBufferSize = 0x100;  // More than enough.
+  uint8_t buffer[kBigBufferSize];
+  buffer[0] = Dlrr::kBlockType;
+  buffer[1] = 0;  // Reserved.
+  buffer[2] = 0;  // Most significant size byte.
+  for (uint8_t size = 3; size < 6; ++size) {
+    buffer[3] = size;
+    Dlrr dlrr;
+    // Parse should be successful only when size is multiple of 3.
+    EXPECT_EQ(size % 3 == 0, dlrr.Parse(buffer, static_cast<uint16_t>(size)));
+  }
+}
+
+TEST(RtcpPacketDlrrTest, FailsOnTooManySubBlocks) {
+  Dlrr dlrr;
+  for (size_t i = 1; i <= Dlrr::kMaxNumberOfDlrrItems; ++i) {
+    EXPECT_TRUE(dlrr.WithDlrrItem(kSsrc + i, kLastRR + i, kDelay + i));
+  }
+  EXPECT_FALSE(dlrr.WithDlrrItem(kSsrc, kLastRR, kDelay));
+}
+
+TEST(RtcpPacketDlrrTest, CreateAndParseMaxSubBlocks) {
+  const size_t kBufferSize = 0x1000;  // More than enough.
+  uint8_t buffer[kBufferSize];
+
+  // Create.
+  Dlrr dlrr;
+  for (size_t i = 1; i <= Dlrr::kMaxNumberOfDlrrItems; ++i) {
+    EXPECT_TRUE(dlrr.WithDlrrItem(kSsrc + i, kLastRR + i, kDelay + i));
+  }
+  size_t used_buffer_size = dlrr.BlockLength();
+  ASSERT_LE(used_buffer_size, kBufferSize);
+  dlrr.Create(buffer);
+
+  // Parse.
+  Dlrr parsed;
+  uint16_t block_length = ByteReader<uint16_t>::ReadBigEndian(&buffer[2]);
+  EXPECT_EQ(used_buffer_size, (block_length + 1) * 4u);
+  EXPECT_TRUE(parsed.Parse(buffer, block_length));
+  EXPECT_TRUE(parsed.sub_blocks().size() == Dlrr::kMaxNumberOfDlrrItems);
+}
+
+}  // namespace
+}  // namespace webrtc