Add FlexfecPacketGenerator. (pt. 9)

webrtc/modules/rtp_rtcp/source/fec_test_helper.cc

Index: webrtc/modules/rtp_rtcp/source/fec_test_helper.cc
diff --git a/webrtc/modules/rtp_rtcp/source/fec_test_helper.cc b/webrtc/modules/rtp_rtcp/source/fec_test_helper.cc
index 69a87a8bf2b57f8b9be17c35806b43038ee1df19..d8af53a396bbafcb95a4e703d2968afd0a4b53db 100644
--- a/webrtc/modules/rtp_rtcp/source/fec_test_helper.cc
+++ b/webrtc/modules/rtp_rtcp/source/fec_test_helper.cc
@@ -13,6 +13,8 @@
 #include <memory>
 #include <utility>
 
+#include "webrtc/base/checks.h"
+#include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 #include "webrtc/modules/rtp_rtcp/source/byte_io.h"
 #include "webrtc/modules/rtp_rtcp/source/rtp_utility.h"
 
@@ -135,6 +137,36 @@ void AugmentedPacketGenerator::WriteRtpHeader(const RTPHeader& header,
   ByteWriter<uint32_t>::WriteBigEndian(data + 8, header.ssrc);
 }
 
+FlexfecPacketGenerator::FlexfecPacketGenerator(uint32_t media_ssrc,
+                                               uint32_t flexfec_ssrc)
+    : AugmentedPacketGenerator(media_ssrc),
+      flexfec_ssrc_(flexfec_ssrc),
+      flexfec_seq_num_(0),
+      flexfec_timestamp_(0) {}
+
+std::unique_ptr<AugmentedPacket> FlexfecPacketGenerator::BuildFlexfecPacket(
+    const ForwardErrorCorrection::Packet& packet) {
+  RTC_DCHECK_LE(packet.length,
+                static_cast<size_t>(IP_PACKET_SIZE - kRtpHeaderSize));
+
+  RTPHeader header;
+  header.sequenceNumber = flexfec_seq_num_;
+  ++flexfec_seq_num_;
+  header.timestamp = flexfec_timestamp_;
+  flexfec_timestamp_ += 3000;

[philipel, 2016/09/21 11:15:27]

constexpr int kMagicConstantWithSomeDescriptiveName = 3000;

[brandtr, 2016/09/21 11:59:21]

Done.

+  header.ssrc = flexfec_ssrc_;
+
+  std::unique_ptr<AugmentedPacket> packet_with_rtp_header(
+      new AugmentedPacket());
+  memset(packet_with_rtp_header->data, 0, IP_PACKET_SIZE);

[philipel, 2016/09/21 11:15:27]

Do you really need to zero this memory?

[brandtr, 2016/09/21 11:59:21]

No, this was overly cautious of me.

Parts of the FEC code depends on the tail memory being zero (I will try to get
rid of that assumption, later on), but the FlexfecReceiver that will be tested
using this helper class should not depend on that.

+  WriteRtpHeader(header, packet_with_rtp_header->data);
+  memcpy(packet_with_rtp_header->data + kRtpHeaderSize, packet.data,
+         packet.length);
+  packet_with_rtp_header->length = kRtpHeaderSize + packet.length;
+
+  return packet_with_rtp_header;
+}
+
 UlpfecPacketGenerator::UlpfecPacketGenerator(uint32_t ssrc)
     : AugmentedPacketGenerator(ssrc) {}