RentACodec: New class that takes over part of ACMCodecDB's job

webrtc/modules/audio_coding/main/acm2/rent_a_codec.cc

Index: webrtc/modules/audio_coding/main/acm2/rent_a_codec.cc
diff --git a/webrtc/modules/audio_coding/main/acm2/rent_a_codec.cc b/webrtc/modules/audio_coding/main/acm2/rent_a_codec.cc
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+++ b/webrtc/modules/audio_coding/main/acm2/rent_a_codec.cc
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+/*
+ *  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/main/acm2/rent_a_codec.h"
+
+#include "webrtc/modules/audio_coding/main/acm2/acm_codec_database.h"
+#include "webrtc/modules/audio_coding/main/acm2/acm_common_defs.h"
+
+namespace webrtc {
+namespace acm2 {
+
+rtc::Maybe<RentACodec::CodecId> RentACodec::CodecIdByParams(
+    const char* payload_name,
+    int sampling_freq_hz,
+    int channels) {
+  return CodecIdFromIndex(
+      ACMCodecDB::CodecId(payload_name, sampling_freq_hz, channels));
+}
+
+rtc::Maybe<CodecInst> RentACodec::CodecInstById(CodecId codec_id) {
+  rtc::Maybe<int> mi = CodecIndexFromId(codec_id);
+  return mi ? rtc::Maybe<CodecInst>(Database()[*mi]) : rtc::Maybe<CodecInst>();
+}
+
+rtc::Maybe<CodecInst> RentACodec::CodecInstByParams(const char* payload_name,
+                                                    int sampling_freq_hz,
+                                                    int channels) {
+  rtc::Maybe<CodecId> codec_id =
+      CodecIdByParams(payload_name, sampling_freq_hz, channels);
+  if (!codec_id)
+    return rtc::Maybe<CodecInst>();
+  rtc::Maybe<CodecInst> ci = CodecInstById(*codec_id);
+  RTC_DCHECK(ci);
+
+  // Keep the number of channels from the function call. For most codecs it
+  // will be the same value as in default codec settings, but not for all.
+  ci->channels = channels;
+
+  return ci;
+}
+
+bool RentACodec::IsCodecValid(const CodecInst& codec_inst) {
+  return ACMCodecDB::CodecNumber(codec_inst) >= 0;
+}
+
+rtc::ArrayView<const CodecInst> RentACodec::Database() {
+  return rtc::ArrayView<const CodecInst>(ACMCodecDB::database_,
+                                         NumberOfCodecs());
+}
+
+}  // namespace acm2
+}  // namespace webrtc