Cache the subtype of each DecoderInfo to make the Is* checks quicker.

webrtc/modules/audio_coding/neteq/decoder_database.h

 /*
  *  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 47 matching lines @@
 
     int SampleRateHz() const {
       const AudioDecoder* decoder = GetDecoder();
       RTC_DCHECK_EQ(1, !!decoder + !!cng_decoder_);
       return decoder ? decoder->SampleRateHz() : cng_decoder_->sample_rate_hz;
     }
 
     const SdpAudioFormat& GetFormat() const { return audio_format_; }
 
     // Returns true if the decoder's format is comfort noise.
-    bool IsComfortNoise() const;
+    bool IsComfortNoise() const {
+      RTC_DCHECK_EQ(!!cng_decoder_, subtype_ == Subtype::kComfortNoise);
+      return subtype_ == Subtype::kComfortNoise;
+    }
 
     // Returns true if the decoder's format is DTMF.
-    bool IsDtmf() const;
+    bool IsDtmf() const {
+      return subtype_ == Subtype::kDtmf;
+    }
 
     // Returns true if the decoder's format is RED.
-    bool IsRed() const;
+    bool IsRed() const {
+      return subtype_ == Subtype::kRed;
+    }
 
     // Returns true if the decoder's format is named |name|.
     bool IsType(const char* name) const;
     // Returns true if the decoder's format is named |name|.
     bool IsType(const std::string& name) const;
 
     // TODO(ossu): |name| is kept here while we retain the old external decoder
     //             interface. Remove this once using an AudioDecoderFactory has
     //             supplanted the old functionality.
     std::string name;
 
    private:
     const SdpAudioFormat audio_format_;
     AudioDecoderFactory* const factory_;
     mutable std::unique_ptr<AudioDecoder> decoder_;
 
     // Set iff this is an external decoder.
     AudioDecoder* const external_decoder_;
 
     // Set iff this is a comfort noise decoder.
     struct CngDecoder {
       static rtc::Optional<CngDecoder> Create(const SdpAudioFormat& format);
       int sample_rate_hz;
     };
     const rtc::Optional<CngDecoder> cng_decoder_;
+
+    enum class Subtype : int8_t {
+      kNormal,
+      kComfortNoise,
+      kDtmf,
+      kRed
+    };
+
+    static Subtype SubtypeFromFormat(const SdpAudioFormat& format);
+
+    const Subtype subtype_;
   };
 
   // Maximum value for 8 bits, and an invalid RTP payload type (since it is
   // only 7 bits).
   static const uint8_t kRtpPayloadTypeError = 0xFF;
 
   DecoderDatabase(
       const rtc::scoped_refptr<AudioDecoderFactory>& decoder_factory);
 
   virtual ~DecoderDatabase();
@@ skipping 87 matching lines @@
   int active_decoder_type_;
   int active_cng_decoder_type_;
   mutable std::unique_ptr<ComfortNoiseDecoder> active_cng_decoder_;
   rtc::scoped_refptr<AudioDecoderFactory> decoder_factory_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(DecoderDatabase);
 };
 
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_DECODER_DATABASE_H_