Refactor some loops and remove double iteration.

webrtc/media/engine/webrtcvideoengine.cc

 /*
  *  Copyright (c) 2014 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 2137 matching lines @@
     return rtc::Optional<uint32_t>(primary_ssrcs[0]);
   }
 }
 
 WebRtcVideoChannel::WebRtcVideoReceiveStream::AllocatedDecoder
 WebRtcVideoChannel::WebRtcVideoReceiveStream::CreateOrReuseVideoDecoder(
     std::vector<AllocatedDecoder>* old_decoders,
     const VideoCodec& codec) {
   webrtc::VideoCodecType type = webrtc::PayloadStringToCodecType(codec.name);
 
-  for (size_t i = 0; i < old_decoders->size(); ++i) {
-    if ((*old_decoders)[i].type == type) {
-      AllocatedDecoder decoder = (*old_decoders)[i];
-      (*old_decoders)[i] = old_decoders->back();
-      old_decoders->pop_back();
-      return decoder;
-    }
+  const auto& found = std::find_if(
+      old_decoders->begin(), old_decoders->end(),
+      [type](const AllocatedDecoder decoder) { return decoder.type == type; });
+  if (found != old_decoders->end()) {
+    AllocatedDecoder decoder = *found;
+    old_decoders->erase(found);
+    return decoder;
   }
 
   if (external_decoder_factory_ != NULL) {
     webrtc::VideoDecoder* decoder =
         external_decoder_factory_->CreateVideoDecoderWithParams(
             type, {stream_params_.id});
     if (decoder != NULL) {
       return AllocatedDecoder(decoder, type, true /* is_external */);
     }
   }
 
   InternalDecoderFactory internal_decoder_factory;
   return AllocatedDecoder(internal_decoder_factory.CreateVideoDecoderWithParams(
                               type, {stream_params_.id}),
                           type, false /* is_external */);
 }
 
 void WebRtcVideoChannel::WebRtcVideoReceiveStream::ConfigureCodecs(
     const std::vector<VideoCodecSettings>& recv_codecs,
     std::vector<AllocatedDecoder>* old_decoders) {
   *old_decoders = allocated_decoders_;
   allocated_decoders_.clear();
   config_.decoders.clear();
-  for (size_t i = 0; i < recv_codecs.size(); ++i) {
+  config_.rtp.rtx_associated_payload_types.clear();
+  for (const auto& recv_codec : recv_codecs) {
     AllocatedDecoder allocated_decoder =
-        CreateOrReuseVideoDecoder(old_decoders, recv_codecs[i].codec);
+        CreateOrReuseVideoDecoder(old_decoders, recv_codec.codec);
     allocated_decoders_.push_back(allocated_decoder);
 
     webrtc::VideoReceiveStream::Decoder decoder;
     decoder.decoder = allocated_decoder.decoder;
-    decoder.payload_type = recv_codecs[i].codec.id;
-    decoder.payload_name = recv_codecs[i].codec.name;
-    decoder.codec_params = recv_codecs[i].codec.params;
+    decoder.payload_type = recv_codec.codec.id;
+    decoder.payload_name = recv_codec.codec.name;
+    decoder.codec_params = recv_codec.codec.params;
     config_.decoders.push_back(decoder);
-  }
-
-  config_.rtp.rtx_associated_payload_types.clear();
-  for (const VideoCodecSettings& recv_codec : recv_codecs) {
     config_.rtp.rtx_associated_payload_types[recv_codec.rtx_payload_type] =
         recv_codec.codec.id;
   }
 
   config_.rtp.ulpfec = recv_codecs.front().ulpfec;
 
   config_.rtp.nack.rtp_history_ms =
       HasNack(recv_codecs.begin()->codec) ? kNackHistoryMs : 0;
 }
 
@@ skipping 124 matching lines @@
 
 void WebRtcVideoChannel::WebRtcVideoReceiveStream::
     MaybeDissociateFlexfecFromVideo() {
   if (stream_ && flexfec_stream_) {
     stream_->RemoveSecondarySink(flexfec_stream_);
   }
 }
 
 void WebRtcVideoChannel::WebRtcVideoReceiveStream::ClearDecoders(
     std::vector<AllocatedDecoder>* allocated_decoders) {
-  for (size_t i = 0; i < allocated_decoders->size(); ++i) {
-    if ((*allocated_decoders)[i].external) {
-      external_decoder_factory_->DestroyVideoDecoder(
-          (*allocated_decoders)[i].external_decoder);
-    }
-    delete (*allocated_decoders)[i].decoder;
+  for (auto& dec : *allocated_decoders) {
+    if (dec.external)
+      external_decoder_factory_->DestroyVideoDecoder(dec.external_decoder);
+    delete dec.decoder;
   }
   allocated_decoders->clear();
 }
 
 void WebRtcVideoChannel::WebRtcVideoReceiveStream::OnFrame(
     const webrtc::VideoFrame& frame) {
   rtc::CritScope crit(&sink_lock_);
 
   if (first_frame_timestamp_ < 0)
     first_frame_timestamp_ = frame.timestamp();
@@ skipping 265 matching lines @@
     stream.temporal_layer_thresholds_bps.resize(GetDefaultVp9TemporalLayers() -
                                                 1);
   }
 
   std::vector<webrtc::VideoStream> streams;
   streams.push_back(stream);
   return streams;
 }
 
 }  // namespace cricket