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      1 /*
      2  * Copyright (C) 2008-2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ANDROID_AUDIOPARAMETER_H_
     18 #define ANDROID_AUDIOPARAMETER_H_
     19 
     20 #include <utils/Errors.h>
     21 #include <utils/KeyedVector.h>
     22 #include <utils/String8.h>
     23 
     24 namespace android {
     25 
     26 class AudioParameter {
     27 
     28 public:
     29     AudioParameter() {}
     30     AudioParameter(const String8& keyValuePairs);
     31     virtual ~AudioParameter();
     32 
     33     // reserved parameter keys for changing standard parameters with setParameters() function.
     34     // Using these keys is mandatory for AudioFlinger to properly monitor audio output/input
     35     // configuration changes and act accordingly.
     36     //  keyRouting: to change audio routing, value is an int in audio_devices_t
     37     //  keySamplingRate: to change sampling rate routing, value is an int
     38     //  keyFormat: to change audio format, value is an int in audio_format_t
     39     //  keyChannels: to change audio channel configuration, value is an int in audio_channels_t
     40     //  keyFrameCount: to change audio output frame count, value is an int
     41     //  keyInputSource: to change audio input source, value is an int in audio_source_t
     42     //     (defined in media/mediarecorder.h)
     43     //  keyScreenState: either "on" or "off"
     44     static const char * const keyRouting;
     45     static const char * const keySamplingRate;
     46     static const char * const keyFormat;
     47     static const char * const keyChannels;
     48     static const char * const keyFrameCount;
     49     static const char * const keyInputSource;
     50     static const char * const keyScreenState;
     51 
     52     //  keyBtNrec: BT SCO Noise Reduction + Echo Cancellation parameters
     53     //  keyHwAvSync: get HW synchronization source identifier from a device
     54     //  keyMonoOutput: Enable mono audio playback
     55     //  keyStreamHwAvSync: set HW synchronization source identifier on a stream
     56     static const char * const keyBtNrec;
     57     static const char * const keyHwAvSync;
     58     static const char * const keyMonoOutput;
     59     static const char * const keyStreamHwAvSync;
     60 
     61     //  keyStreamConnect / Disconnect: value is an int in audio_devices_t
     62     static const char * const keyStreamConnect;
     63     static const char * const keyStreamDisconnect;
     64 
     65     // For querying stream capabilities. All the returned values are lists.
     66     //   keyStreamSupportedFormats: audio_format_t
     67     //   keyStreamSupportedChannels: audio_channel_mask_t
     68     //   keyStreamSupportedSamplingRates: sampling rate values
     69     static const char * const keyStreamSupportedFormats;
     70     static const char * const keyStreamSupportedChannels;
     71     static const char * const keyStreamSupportedSamplingRates;
     72 
     73     static const char * const valueOn;
     74     static const char * const valueOff;
     75 
     76     static const char * const valueListSeparator;
     77 
     78     String8 toString() const { return toStringImpl(true); }
     79     String8 keysToString() const { return toStringImpl(false); }
     80 
     81     status_t add(const String8& key, const String8& value);
     82     status_t addInt(const String8& key, const int value);
     83     status_t addKey(const String8& key);
     84     status_t addFloat(const String8& key, const float value);
     85 
     86     status_t remove(const String8& key);
     87 
     88     status_t get(const String8& key, String8& value) const;
     89     status_t getInt(const String8& key, int& value) const;
     90     status_t getFloat(const String8& key, float& value) const;
     91     status_t getAt(size_t index, String8& key) const;
     92     status_t getAt(size_t index, String8& key, String8& value) const;
     93 
     94     size_t size() const { return mParameters.size(); }
     95 
     96 private:
     97     String8 mKeyValuePairs;
     98     KeyedVector <String8, String8> mParameters;
     99 
    100     String8 toStringImpl(bool useValues) const;
    101 };
    102 
    103 };  // namespace android
    104 
    105 #endif  /*ANDROID_AUDIOPARAMETER_H_*/
    106