1/*
2 * Copyright (C) 2017 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#define LOG_TAG "AAudioService"
18//#define LOG_NDEBUG 0
19#include <utils/Log.h>
20
21#include <cstring>
22#include "AAudioMixer.h"
23
24using android::WrappingBuffer;
25using android::FifoBuffer;
26using android::fifo_frames_t;
27
28AAudioMixer::~AAudioMixer() {
29    delete[] mOutputBuffer;
30}
31
32void AAudioMixer::allocate(int32_t samplesPerFrame, int32_t framesPerBurst) {
33    mSamplesPerFrame = samplesPerFrame;
34    mFramesPerBurst = framesPerBurst;
35    int32_t samplesPerBuffer = samplesPerFrame * framesPerBurst;
36    mOutputBuffer = new float[samplesPerBuffer];
37    mBufferSizeInBytes = samplesPerBuffer * sizeof(float);
38}
39
40void AAudioMixer::clear() {
41    memset(mOutputBuffer, 0, mBufferSizeInBytes);
42}
43
44bool AAudioMixer::mix(FifoBuffer *fifo, float volume) {
45    WrappingBuffer wrappingBuffer;
46    float *destination = mOutputBuffer;
47    fifo_frames_t framesLeft = mFramesPerBurst;
48
49    // Gather the data from the client. May be in two parts.
50    fifo->getFullDataAvailable(&wrappingBuffer);
51
52    // Mix data in one or two parts.
53    int partIndex = 0;
54    while (framesLeft > 0 && partIndex < WrappingBuffer::SIZE) {
55        fifo_frames_t framesToMix = framesLeft;
56        fifo_frames_t framesAvailable = wrappingBuffer.numFrames[partIndex];
57        if (framesAvailable > 0) {
58            if (framesToMix > framesAvailable) {
59                framesToMix = framesAvailable;
60            }
61            mixPart(destination, (float *)wrappingBuffer.data[partIndex], framesToMix, volume);
62
63            destination += framesToMix * mSamplesPerFrame;
64            framesLeft -= framesToMix;
65        }
66        partIndex++;
67    }
68    fifo->getFifoControllerBase()->advanceReadIndex(mFramesPerBurst - framesLeft);
69    if (framesLeft > 0) {
70        //ALOGW("AAudioMixer::mix() UNDERFLOW by %d / %d frames ----- UNDERFLOW !!!!!!!!!!",
71        //      framesLeft, mFramesPerBurst);
72    }
73    return (framesLeft > 0); // did not get all the frames we needed, ie. "underflow"
74}
75
76void AAudioMixer::mixPart(float *destination, float *source, int32_t numFrames, float volume) {
77    int32_t numSamples = numFrames * mSamplesPerFrame;
78    // TODO maybe optimize using SIMD
79    for (int sampleIndex = 0; sampleIndex < numSamples; sampleIndex++) {
80        *destination++ += *source++ * volume;
81    }
82}
83
84float *AAudioMixer::getOutputBuffer() {
85    return mOutputBuffer;
86}
87