DecoderDatabase::IsComfortNoise: Improved efficiency.

webrtc/modules/audio_coding/neteq/decoder_database.cc

 /*
  *  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.
  */
 
@@ skipping 151 matching lines @@
                              NetEqDecoder codec_type) const {
   DecoderMap::const_iterator it = decoders_.find(rtp_payload_type);
   if (it == decoders_.end()) {
     // Decoder not found.
     return false;
   }
   return ((*it).second.codec_type == codec_type);
 }
 
 bool DecoderDatabase::IsComfortNoise(uint8_t rtp_payload_type) const {
-  if (IsType(rtp_payload_type, NetEqDecoder::kDecoderCNGnb) ||
-      IsType(rtp_payload_type, NetEqDecoder::kDecoderCNGwb) ||
-      IsType(rtp_payload_type, NetEqDecoder::kDecoderCNGswb32kHz) ||
-      IsType(rtp_payload_type, NetEqDecoder::kDecoderCNGswb48kHz)) {
-    return true;
-  } else {
+  DecoderMap::const_iterator it = decoders_.find(rtp_payload_type);
+  if (it == decoders_.end()) {
+    // Decoder not found.
     return false;
   }

[kwiberg-webrtc, 2016/04/27 12:16:34]

Suggestion for future improvement: If we're having performance problems with a
map whose keys are 7-bit integers, replacing the balanced binary tree with a
128-element array could be a big win.

+  const auto& type = it->second.codec_type;
+  return type == NetEqDecoder::kDecoderCNGnb
+      || type == NetEqDecoder::kDecoderCNGwb
+      || type == NetEqDecoder::kDecoderCNGswb32kHz
+      || type == NetEqDecoder::kDecoderCNGswb48kHz;
 }
 
 bool DecoderDatabase::IsDtmf(uint8_t rtp_payload_type) const {
   return IsType(rtp_payload_type, NetEqDecoder::kDecoderAVT);
 }
 
 bool DecoderDatabase::IsRed(uint8_t rtp_payload_type) const {
   return IsType(rtp_payload_type, NetEqDecoder::kDecoderRED);
 }
 
@@ skipping 77 matching lines @@
       LOG(LS_WARNING) << "CheckPayloadTypes: unknown RTP payload type "
                       << static_cast<int>((*it)->header.payloadType);
       return kDecoderNotFound;
     }
   }
   return kOK;
 }
 
 
 }  // namespace webrtc