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/*
* Copyright (C) 2016 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 org.drrickorang.loopback;
/**
* Maintains a recording of wave data of last n seconds
*/
public class WaveDataRingBuffer {
private final double[] mWaveRecord;
private volatile int index = 0; // between 0 and mWaveRecord.length - 1
private boolean arrayFull = false; // true after index has wrapped
public WaveDataRingBuffer(int size) {
if (size < Constant.SAMPLING_RATE_MIN * Constant.BUFFER_TEST_DURATION_SECONDS_MIN) {
size = Constant.SAMPLING_RATE_MIN * Constant.BUFFER_TEST_DURATION_SECONDS_MIN;
} else if (size > Constant.SAMPLING_RATE_MAX * Constant.BUFFER_TEST_DURATION_SECONDS_MAX) {
size = Constant.SAMPLING_RATE_MAX * Constant.BUFFER_TEST_DURATION_SECONDS_MAX;
}
mWaveRecord = new double[size];
}
/**
* Write length number of doubles from data into ring buffer from starting srcPos
*/
public synchronized void writeWaveData(double[] data, int srcPos, int length) {
if (length > data.length - srcPos) {
// requested to write more data than available
// bad request leave data un-affected
return;
}
if (length >= mWaveRecord.length) {
// requested write would fill or exceed ring buffer capacity
// fill ring buffer with last segment of requested write
System.arraycopy(data, srcPos + (length - mWaveRecord.length), mWaveRecord, 0,
mWaveRecord.length);
index = 0;
} else if (mWaveRecord.length - index > length) {
// write requested data from current offset
System.arraycopy(data, srcPos, mWaveRecord, index, length);
index += length;
} else {
// write to available buffer then wrap and overwrite previous records
if (!arrayFull) {
arrayFull = true;
}
int availBuff = mWaveRecord.length - index;
System.arraycopy(data, srcPos, mWaveRecord, index, availBuff);
System.arraycopy(data, srcPos + availBuff, mWaveRecord, 0, length - availBuff);
index = length - availBuff;
}
}
/**
* Returns a private copy of recorded wave data
*
* @return double array of wave recording, rearranged with oldest sample at first index
*/
public synchronized double[] getWaveRecord() {
double outputBuffer[] = new double[mWaveRecord.length];
if (!arrayFull) {
//return partially filled sample with trailing zeroes
System.arraycopy(mWaveRecord, 0, outputBuffer, 0, index);
} else {
//copy buffer to contiguous sample and return unwrapped array
System.arraycopy(mWaveRecord, index, outputBuffer, 0, mWaveRecord.length - index);
System.arraycopy(mWaveRecord, 0, outputBuffer, mWaveRecord.length - index, index);
}
return outputBuffer;
}
}
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