Moving src/webrtc into src/.

In order to eliminate the WebRTC Subtree mirror in Chromium, 
WebRTC is moving the content of the src/webrtc directory up
to the src/ directory.

NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
TBR=tommi@webrtc.org

Bug: chromium:611808
Change-Id: Iac59c5b51b950f174119565bac87955a7994bc38
Reviewed-on: https://webrtc-review.googlesource.com/1560
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#19845}

modules/audio_coding/neteq/red_payload_splitter.cc

@@ -0,0 +1,162 @@
+/*
+ *  Copyright (c) 2012 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/audio_coding/neteq/red_payload_splitter.h"
+
+#include <assert.h>
+#include <vector>
+
+#include "webrtc/modules/audio_coding/neteq/decoder_database.h"
+#include "webrtc/rtc_base/checks.h"
+#include "webrtc/rtc_base/logging.h"
+#include "webrtc/rtc_base/safe_conversions.h"
+
+namespace webrtc {
+
+// The method loops through a list of packets {A, B, C, ...}. Each packet is
+// split into its corresponding RED payloads, {A1, A2, ...}, which is
+// temporarily held in the list |new_packets|.
+// When the first packet in |packet_list| has been processed, the orignal packet
+// is replaced by the new ones in |new_packets|, so that |packet_list| becomes:
+// {A1, A2, ..., B, C, ...}. The method then continues with B, and C, until all
+// the original packets have been replaced by their split payloads.
+bool RedPayloadSplitter::SplitRed(PacketList* packet_list) {
+  // Too many RED blocks indicates that something is wrong. Clamp it at some
+  // reasonable value.
+  const size_t kMaxRedBlocks = 32;
+  bool ret = true;
+  PacketList::iterator it = packet_list->begin();
+  while (it != packet_list->end()) {
+    const Packet& red_packet = *it;
+    assert(!red_packet.payload.empty());
+    const uint8_t* payload_ptr = red_packet.payload.data();
+
+    // Read RED headers (according to RFC 2198):
+    //
+    //    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
+    //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    //   |F|   block PT  |  timestamp offset         |   block length    |
+    //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    // Last RED header:
+    //    0 1 2 3 4 5 6 7
+    //   +-+-+-+-+-+-+-+-+
+    //   |0|   Block PT  |
+    //   +-+-+-+-+-+-+-+-+
+
+    struct RedHeader {
+      uint8_t payload_type;
+      uint32_t timestamp;
+      size_t payload_length;
+    };
+
+    std::vector<RedHeader> new_headers;
+    bool last_block = false;
+    size_t sum_length = 0;
+    while (!last_block) {
+      RedHeader new_header;
+      // Check the F bit. If F == 0, this was the last block.
+      last_block = ((*payload_ptr & 0x80) == 0);
+      // Bits 1 through 7 are payload type.
+      new_header.payload_type = payload_ptr[0] & 0x7F;
+      if (last_block) {
+        // No more header data to read.
+        ++sum_length;  // Account for RED header size of 1 byte.
+        new_header.timestamp = red_packet.timestamp;
+        new_header.payload_length = red_packet.payload.size() - sum_length;
+        payload_ptr += 1;  // Advance to first payload byte.
+      } else {
+        // Bits 8 through 21 are timestamp offset.
+        int timestamp_offset =
+            (payload_ptr[1] << 6) + ((payload_ptr[2] & 0xFC) >> 2);
+        new_header.timestamp = red_packet.timestamp - timestamp_offset;
+        // Bits 22 through 31 are payload length.
+        new_header.payload_length =
+            ((payload_ptr[2] & 0x03) << 8) + payload_ptr[3];
+        payload_ptr += 4;  // Advance to next RED header.
+      }
+      sum_length += new_header.payload_length;
+      sum_length += 4;  // Account for RED header size of 4 bytes.
+      // Store in new list of packets.
+      new_headers.push_back(new_header);
+    }
+
+    if (new_headers.size() <= kMaxRedBlocks) {
+      // Populate the new packets with payload data.
+      // |payload_ptr| now points at the first payload byte.
+      PacketList new_packets;  // An empty list to store the split packets in.
+      for (size_t i = 0; i != new_headers.size(); ++i) {
+        const auto& new_header = new_headers[i];
+        size_t payload_length = new_header.payload_length;
+        if (payload_ptr + payload_length >
+            red_packet.payload.data() + red_packet.payload.size()) {
+          // The block lengths in the RED headers do not match the overall
+          // packet length. Something is corrupt. Discard this and the remaining
+          // payloads from this packet.
+          LOG(LS_WARNING) << "SplitRed length mismatch";
+          ret = false;
+          break;
+        }
+
+        Packet new_packet;
+        new_packet.timestamp = new_header.timestamp;
+        new_packet.payload_type = new_header.payload_type;
+        new_packet.sequence_number = red_packet.sequence_number;
+        new_packet.priority.red_level =
+            rtc::dchecked_cast<int>((new_headers.size() - 1) - i);
+        new_packet.payload.SetData(payload_ptr, payload_length);
+        new_packets.push_front(std::move(new_packet));
+        payload_ptr += payload_length;
+      }
+      // Insert new packets into original list, before the element pointed to by
+      // iterator |it|.
+      packet_list->splice(it, std::move(new_packets));
+    } else {
+      LOG(LS_WARNING) << "SplitRed too many blocks: " << new_headers.size();
+      ret = false;
+    }
+    // Remove |it| from the packet list. This operation effectively moves the
+    // iterator |it| to the next packet in the list. Thus, we do not have to
+    // increment it manually.
+    it = packet_list->erase(it);
+  }
+  return ret;
+}
+
+int RedPayloadSplitter::CheckRedPayloads(
+    PacketList* packet_list,
+    const DecoderDatabase& decoder_database) {
+  int main_payload_type = -1;
+  int num_deleted_packets = 0;
+  for (auto it = packet_list->begin(); it != packet_list->end(); /* */) {
+    uint8_t this_payload_type = it->payload_type;
+    if (!decoder_database.IsDtmf(this_payload_type) &&
+        !decoder_database.IsComfortNoise(this_payload_type)) {
+      if (main_payload_type == -1) {
+        // This is the first packet in the list which is non-DTMF non-CNG.
+        main_payload_type = this_payload_type;
+      } else {
+        if (this_payload_type != main_payload_type) {
+          // We do not allow redundant payloads of a different type.
+          // Remove |it| from the packet list. This operation effectively
+          // moves the iterator |it| to the next packet in the list. Thus, we
+          // do not have to increment it manually.
+          it = packet_list->erase(it);
+          ++num_deleted_packets;
+          continue;
+        }
+      }
+    }
+    ++it;
+  }
+  return num_deleted_packets;
+}
+
+}  // namespace webrtc