content: /*
   * Copyright (C) 2010 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.media.audiofx;
  
  import android.media.audiofx.AudioEffect;
  import android.util.Log;
  
  import java.util.StringTokenizer;
  
  
  /**
   * Bass boost is an audio effect to boost or amplify low frequencies of the sound. It is comparable
   * to a simple equalizer but limited to one band amplification in the low frequency range.
   * <p>An application creates a BassBoost object to instantiate and control a bass boost engine in
   * the audio framework.
   * <p>The methods, parameter types and units exposed by the BassBoost implementation are directly
   * mapping those defined by the OpenSL ES 1.0.1 Specification (http://www.khronos.org/opensles/)
   * for the SLBassBoostItf interface. Please refer to this specification for more details.
   * <p>To attach the BassBoost to a particular AudioTrack or MediaPlayer, specify the audio session
   * ID of this AudioTrack or MediaPlayer when constructing the BassBoost.
   * <p>NOTE: attaching a BassBoost to the global audio output mix by use of session 0 is deprecated.
   * <p>See {@link android.media.MediaPlayer#getAudioSessionId()} for details on audio sessions.
   * <p>See {@link android.media.audiofx.AudioEffect} class for more details on
   * controlling audio effects.
   */
  
  public class BassBoost extends AudioEffect {
  
      private final static String TAG = "BassBoost";
  
      // These constants must be synchronized with those in
      // frameworks/base/include/media/EffectBassBoostApi.h
      /**
       * Is strength parameter supported by bass boost engine. Parameter ID for getParameter().
       */
      public static final int PARAM_STRENGTH_SUPPORTED = 0;
      /**
       * Bass boost effect strength. Parameter ID for
       * {@link android.media.audiofx.BassBoost.OnParameterChangeListener}
       */
      public static final int PARAM_STRENGTH = 1;
  
      /**
       * Indicates if strength parameter is supported by the bass boost engine
       */
      private boolean mStrengthSupported = false;
  
      /**
       * Registered listener for parameter changes.
       */
      private OnParameterChangeListener mParamListener = null;
  
      /**
       * Listener used internally to to receive raw parameter change event from AudioEffect super class
       */
      private BaseParameterListener mBaseParamListener = null;
  
      /**
       * Lock for access to mParamListener
       */
      private final Object mParamListenerLock = new Object();
  
      /**
       * Class constructor.
       * @param priority the priority level requested by the application for controlling the BassBoost
       * engine. As the same engine can be shared by several applications, this parameter indicates
       * how much the requesting application needs control of effect parameters. The normal priority
       * is 0, above normal is a positive number, below normal a negative number.
       * @param audioSession system wide unique audio session identifier. The BassBoost will be
       * attached to the MediaPlayer or AudioTrack in the same audio session.
       *
       * @throws java.lang.IllegalStateException
       * @throws java.lang.IllegalArgumentException
       * @throws java.lang.UnsupportedOperationException
       * @throws java.lang.RuntimeException
       */
      public BassBoost(int priority, int audioSession)
      throws IllegalStateException, IllegalArgumentException,
             UnsupportedOperationException, RuntimeException {
          super(EFFECT_TYPE_BASS_BOOST, EFFECT_TYPE_NULL, priority, audioSession);
  
          if (audioSession == 0) {
              Log.w(TAG, "WARNING: attaching a BassBoost to global output mix is deprecated!");
          }
  
          int[] value = new int[1];
          checkStatus(getParameter(PARAM_STRENGTH_SUPPORTED, value));
          mStrengthSupported = (value[0] != 0);
      }
  
      /**
       * Indicates whether setting strength is supported. If this method returns false, only one
       * strength is supported and the setStrength() method always rounds to that value.
       * @return true is strength parameter is supported, false otherwise
       */
      public boolean getStrengthSupported() {
         return mStrengthSupported;
      }
  
      /**
       * Sets the strength of the bass boost effect. If the implementation does not support per mille
       * accuracy for setting the strength, it is allowed to round the given strength to the nearest
       * supported value. You can use the {@link #getRoundedStrength()} method to query the
       * (possibly rounded) value that was actually set.
       * @param strength strength of the effect. The valid range for strength strength is [0, 1000],
       * where 0 per mille designates the mildest effect and 1000 per mille designates the strongest.
       * @throws IllegalStateException
       * @throws IllegalArgumentException
       * @throws UnsupportedOperationException
       */
      public void setStrength(short strength)
      throws IllegalStateException, IllegalArgumentException, UnsupportedOperationException {
          checkStatus(setParameter(PARAM_STRENGTH, strength));
      }
  
      /**
       * Gets the current strength of the effect.
       * @return the strength of the effect. The valid range for strength is [0, 1000], where 0 per
       * mille designates the mildest effect and 1000 per mille the strongest
       * @throws IllegalStateException
       * @throws IllegalArgumentException
       * @throws UnsupportedOperationException
       */
      public short getRoundedStrength()
      throws IllegalStateException, IllegalArgumentException, UnsupportedOperationException {
          short[] value = new short[1];
          checkStatus(getParameter(PARAM_STRENGTH, value));
          return value[0];
      }
  
      /**
       * The OnParameterChangeListener interface defines a method called by the BassBoost when a
       * parameter value has changed.
       */
      public interface OnParameterChangeListener  {
          /**
           * Method called when a parameter value has changed. The method is called only if the
           * parameter was changed by another application having the control of the same
           * BassBoost engine.
           * @param effect the BassBoost on which the interface is registered.
           * @param status status of the set parameter operation.
           * @param param ID of the modified parameter. See {@link #PARAM_STRENGTH} ...
           * @param value the new parameter value.
           */
          void onParameterChange(BassBoost effect, int status, int param, short value);
      }
  
      /**
       * Listener used internally to receive unformatted parameter change events from AudioEffect
       * super class.
       */
      private class BaseParameterListener implements AudioEffect.OnParameterChangeListener {
          private BaseParameterListener() {
  
          }
          public void onParameterChange(AudioEffect effect, int status, byte[] param, byte[] value) {
              OnParameterChangeListener l = null;
  
              synchronized (mParamListenerLock) {
                  if (mParamListener != null) {
                      l = mParamListener;
                  }
              }
              if (l != null) {
                  int p = -1;
                  short v = -1;
  
                  if (param.length == 4) {
                      p = byteArrayToInt(param, 0);
                  }
                  if (value.length == 2) {
                      v = byteArrayToShort(value, 0);
                  }
                  if (p != -1 && v != -1) {
                      l.onParameterChange(BassBoost.this, status, p, v);
                  }
              }
          }
      }
  
      /**
       * Registers an OnParameterChangeListener interface.
       * @param listener OnParameterChangeListener interface registered
       */
      public void setParameterListener(OnParameterChangeListener listener) {
          synchronized (mParamListenerLock) {
              if (mParamListener == null) {
                  mParamListener = listener;
                  mBaseParamListener = new BaseParameterListener();
                  super.setParameterListener(mBaseParamListener);
              }
          }
      }
  
      /**
       * The Settings class regroups all bass boost parameters. It is used in
       * conjuntion with getProperties() and setProperties() methods to backup and restore
       * all parameters in a single call.
       */
      public static class Settings {
          public short strength;
  
          public Settings() {
          }
  
          /**
           * Settings class constructor from a key=value; pairs formatted string. The string is
           * typically returned by Settings.toString() method.
           * @throws IllegalArgumentException if the string is not correctly formatted.
           */
          public Settings(String settings) {
              StringTokenizer st = new StringTokenizer(settings, "=;");
              int tokens = st.countTokens();
              if (st.countTokens() != 3) {
                  throw new IllegalArgumentException("settings: " + settings);
              }
              String key = st.nextToken();
              if (!key.equals("BassBoost")) {
                  throw new IllegalArgumentException(
                          "invalid settings for BassBoost: " + key);
              }
              try {
                  key = st.nextToken();
                  if (!key.equals("strength")) {
                      throw new IllegalArgumentException("invalid key name: " + key);
                  }
                  strength = Short.parseShort(st.nextToken());
               } catch (NumberFormatException nfe) {
                  throw new IllegalArgumentException("invalid value for key: " + key);
              }
          }
  
          @Override
          public String toString() {
              String str = new String (
                      "BassBoost"+
                      ";strength="+Short.toString(strength)
                      );
              return str;
          }
      };
  
  
      /**
       * Gets the bass boost properties. This method is useful when a snapshot of current
       * bass boost settings must be saved by the application.
       * @return a BassBoost.Settings object containing all current parameters values
       * @throws IllegalStateException
       * @throws IllegalArgumentException
       * @throws UnsupportedOperationException
       */
      public BassBoost.Settings getProperties()
      throws IllegalStateException, IllegalArgumentException, UnsupportedOperationException {
          Settings settings = new Settings();
          short[] value = new short[1];
          checkStatus(getParameter(PARAM_STRENGTH, value));
          settings.strength = value[0];
          return settings;
      }
  
      /**
       * Sets the bass boost properties. This method is useful when bass boost settings have to
       * be applied from a previous backup.
       * @param settings a BassBoost.Settings object containing the properties to apply
       * @throws IllegalStateException
       * @throws IllegalArgumentException
       * @throws UnsupportedOperationException
       */
      public void setProperties(BassBoost.Settings settings)
      throws IllegalStateException, IllegalArgumentException, UnsupportedOperationException {
          checkStatus(setParameter(PARAM_STRENGTH, settings.strength));
      }
  }
  