Move AudioDecoderPcm16B next to AudioEncoderPcm16B

All AudioDecoder subclasses have historically lived in NetEq, but they
fit better with the codec they wrap.

BUG=webrtc:4557
R=henrik.lundin@webrtc.org

Review URL: https://codereview.webrtc.org/1348113002 .

Cr-Commit-Position: refs/heads/master@{#9963}

webrtc/modules/audio_coding/codecs/pcm16b/audio_decoder_pcm16b.cc

@@ -0,0 +1,54 @@
+/*
+ *  Copyright (c) 2015 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/codecs/pcm16b/include/audio_decoder_pcm16b.h"
+
+#include "webrtc/base/checks.h"
+#include "webrtc/modules/audio_coding/codecs/pcm16b/include/pcm16b.h"
+
+namespace webrtc {
+
+AudioDecoderPcm16B::AudioDecoderPcm16B() {}
+
+void AudioDecoderPcm16B::Reset() {}
+
+size_t AudioDecoderPcm16B::Channels() const {
+  return 1;
+}
+
+int AudioDecoderPcm16B::DecodeInternal(const uint8_t* encoded,
+                                       size_t encoded_len,
+                                       int sample_rate_hz,
+                                       int16_t* decoded,
+                                       SpeechType* speech_type) {
+  DCHECK(sample_rate_hz == 8000 || sample_rate_hz == 16000 ||
+         sample_rate_hz == 32000 || sample_rate_hz == 48000)
+      << "Unsupported sample rate " << sample_rate_hz;
+  size_t ret = WebRtcPcm16b_Decode(encoded, encoded_len, decoded);
+  *speech_type = ConvertSpeechType(1);
+  return static_cast<int>(ret);
+}
+
+int AudioDecoderPcm16B::PacketDuration(const uint8_t* encoded,
+                                       size_t encoded_len) const {
+  // Two encoded byte per sample per channel.
+  return static_cast<int>(encoded_len / (2 * Channels()));
+}
+
+AudioDecoderPcm16BMultiCh::AudioDecoderPcm16BMultiCh(size_t num_channels)
+    : channels_(num_channels) {
+  DCHECK(num_channels > 0);
+}
+
+size_t AudioDecoderPcm16BMultiCh::Channels() const {
+  return channels_;
+}
+
+}  // namespace webrtc

webrtc/modules/audio_coding/codecs/pcm16b/include/audio_decoder_pcm16b.h

@@ -0,0 +1,48 @@
+/*
+ *  Copyright (c) 2015 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.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_CODECS_PCM16B_INCLUDE_AUDIO_DECODER_PCM16B_H_
+#define WEBRTC_MODULES_AUDIO_CODING_CODECS_PCM16B_INCLUDE_AUDIO_DECODER_PCM16B_H_
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/modules/audio_coding/codecs/audio_decoder.h"
+
+namespace webrtc {
+
+class AudioDecoderPcm16B : public AudioDecoder {
+ public:
+  AudioDecoderPcm16B();
+  void Reset() override;
+  int PacketDuration(const uint8_t* encoded, size_t encoded_len) const override;
+  size_t Channels() const override;
+
+ protected:
+  int DecodeInternal(const uint8_t* encoded,
+                     size_t encoded_len,
+                     int sample_rate_hz,
+                     int16_t* decoded,
+                     SpeechType* speech_type) override;
+
+ private:
+  RTC_DISALLOW_COPY_AND_ASSIGN(AudioDecoderPcm16B);
+};
+
+class AudioDecoderPcm16BMultiCh : public AudioDecoderPcm16B {
+ public:
+  explicit AudioDecoderPcm16BMultiCh(size_t num_channels);
+  size_t Channels() const override;
+
+ private:
+  const size_t channels_;
+  RTC_DISALLOW_COPY_AND_ASSIGN(AudioDecoderPcm16BMultiCh);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_CODECS_PCM16B_INCLUDE_AUDIO_DECODER_PCM16B_H_

webrtc/modules/audio_coding/codecs/pcm16b/pcm16b.gypi

@@ -26,8 +26,10 @@
         ],
       },
       'sources': [
+        'include/audio_decoder_pcm16b.h',
         'include/audio_encoder_pcm16b.h',
         'include/pcm16b.h',
+        'audio_decoder_pcm16b.cc',
         'audio_encoder_pcm16b.cc',
         'pcm16b.c',
       ],