FifoBuffer.cpp revision c0c70e3c7dd10bc2c0caffcab1f3f5fb406b35fb 
1/*
2 * Copyright 2015 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#include <cstring>
18#include <unistd.h>
19
20
21#define LOG_TAG "FifoBuffer"
22//#define LOG_NDEBUG 0
23#include <utils/Log.h>
24
25#include "FifoControllerBase.h"
26#include "FifoController.h"
27#include "FifoControllerIndirect.h"
28#include "FifoBuffer.h"
29
30using namespace android; // TODO just import names needed
31
32FifoBuffer::FifoBuffer(int32_t bytesPerFrame, fifo_frames_t capacityInFrames)
33        : mFrameCapacity(capacityInFrames)
34        , mBytesPerFrame(bytesPerFrame)
35        , mStorage(nullptr)
36        , mFramesReadCount(0)
37        , mFramesUnderrunCount(0)
38        , mUnderrunCount(0)
39{
40    // TODO Handle possible failures to allocate. Move out of constructor?
41    mFifo = new FifoController(capacityInFrames, capacityInFrames);
42    // allocate buffer
43    int32_t bytesPerBuffer = bytesPerFrame * capacityInFrames;
44    mStorage = new uint8_t[bytesPerBuffer];
45    mStorageOwned = true;
46    ALOGD("FifoBuffer: capacityInFrames = %d, bytesPerFrame = %d",
47          capacityInFrames, bytesPerFrame);
48}
49
50FifoBuffer::FifoBuffer( int32_t   bytesPerFrame,
51                        fifo_frames_t   capacityInFrames,
52                        fifo_counter_t *  readIndexAddress,
53                        fifo_counter_t *  writeIndexAddress,
54                        void *  dataStorageAddress
55                        )
56        : mFrameCapacity(capacityInFrames)
57        , mBytesPerFrame(bytesPerFrame)
58        , mStorage(static_cast<uint8_t *>(dataStorageAddress))
59        , mFramesReadCount(0)
60        , mFramesUnderrunCount(0)
61        , mUnderrunCount(0)
62{
63    // TODO Handle possible failures to allocate. Move out of constructor?
64    mFifo = new FifoControllerIndirect(capacityInFrames,
65                                       capacityInFrames,
66                                       readIndexAddress,
67                                       writeIndexAddress);
68    mStorageOwned = false;
69    ALOGD("FifoProcessor: capacityInFrames = %d, bytesPerFrame = %d",
70          capacityInFrames, bytesPerFrame);
71}
72
73FifoBuffer::~FifoBuffer() {
74    if (mStorageOwned) {
75        delete[] mStorage;
76    }
77    delete mFifo;
78}
79
80
81int32_t FifoBuffer::convertFramesToBytes(fifo_frames_t frames) {
82    return frames * mBytesPerFrame;
83}
84
85void FifoBuffer::fillWrappingBuffer(WrappingBuffer *wrappingBuffer,
86                                    int32_t framesAvailable,
87                                    int32_t startIndex) {
88    wrappingBuffer->data[1] = nullptr;
89    wrappingBuffer->numFrames[1] = 0;
90    if (framesAvailable > 0) {
91
92        uint8_t *source = &mStorage[convertFramesToBytes(startIndex)];
93        // Does the available data cross the end of the FIFO?
94        if ((startIndex + framesAvailable) > mFrameCapacity) {
95            wrappingBuffer->data[0] = source;
96            wrappingBuffer->numFrames[0] = mFrameCapacity - startIndex;
97            wrappingBuffer->data[1] = &mStorage[0];
98            wrappingBuffer->numFrames[1] = mFrameCapacity - startIndex;
99
100        } else {
101            wrappingBuffer->data[0] = source;
102            wrappingBuffer->numFrames[0] = framesAvailable;
103        }
104    } else {
105        wrappingBuffer->data[0] = nullptr;
106        wrappingBuffer->numFrames[0] = 0;
107    }
108
109}
110
111void FifoBuffer::getFullDataAvailable(WrappingBuffer *wrappingBuffer) {
112    fifo_frames_t framesAvailable = mFifo->getFullFramesAvailable();
113    fifo_frames_t startIndex = mFifo->getReadIndex();
114    fillWrappingBuffer(wrappingBuffer, framesAvailable, startIndex);
115}
116
117void FifoBuffer::getEmptyRoomAvailable(WrappingBuffer *wrappingBuffer) {
118    fifo_frames_t framesAvailable = mFifo->getEmptyFramesAvailable();
119    fifo_frames_t startIndex = mFifo->getWriteIndex();
120    fillWrappingBuffer(wrappingBuffer, framesAvailable, startIndex);
121}
122
123fifo_frames_t FifoBuffer::read(void *buffer, fifo_frames_t numFrames) {
124    WrappingBuffer wrappingBuffer;
125    uint8_t *destination = (uint8_t *) buffer;
126    fifo_frames_t framesLeft = numFrames;
127
128    getFullDataAvailable(&wrappingBuffer);
129
130    // Read data in one or two parts.
131    int partIndex = 0;
132    while (framesLeft > 0 && partIndex < WrappingBuffer::SIZE) {
133        fifo_frames_t framesToRead = framesLeft;
134        fifo_frames_t framesAvailable = wrappingBuffer.numFrames[partIndex];
135        //ALOGD("FifoProcessor::read() framesAvailable = %d, partIndex = %d",
136        //      framesAvailable, partIndex);
137        if (framesAvailable > 0) {
138            if (framesToRead > framesAvailable) {
139                framesToRead = framesAvailable;
140            }
141            int32_t numBytes = convertFramesToBytes(framesToRead);
142            memcpy(destination, wrappingBuffer.data[partIndex], numBytes);
143
144            destination += numBytes;
145            framesLeft -= framesToRead;
146        }
147        partIndex++;
148    }
149    fifo_frames_t framesRead = numFrames - framesLeft;
150    mFifo->advanceReadIndex(framesRead);
151    return framesRead;
152}
153
154fifo_frames_t FifoBuffer::write(const void *buffer, fifo_frames_t numFrames) {
155    WrappingBuffer wrappingBuffer;
156    uint8_t *source = (uint8_t *) buffer;
157    fifo_frames_t framesLeft = numFrames;
158
159    getEmptyRoomAvailable(&wrappingBuffer);
160
161    // Read data in one or two parts.
162    int partIndex = 0;
163    while (framesLeft > 0 && partIndex < WrappingBuffer::SIZE) {
164        fifo_frames_t framesToWrite = framesLeft;
165        fifo_frames_t framesAvailable = wrappingBuffer.numFrames[partIndex];
166        if (framesAvailable > 0) {
167            if (framesToWrite > framesAvailable) {
168                framesToWrite = framesAvailable;
169            }
170            int32_t numBytes = convertFramesToBytes(framesToWrite);
171            memcpy(wrappingBuffer.data[partIndex], source, numBytes);
172
173            source += numBytes;
174            framesLeft -= framesToWrite;
175        }
176        partIndex++;
177    }
178    fifo_frames_t framesWritten = numFrames - framesLeft;
179    mFifo->advanceWriteIndex(framesWritten);
180    return framesWritten;
181}
182
183fifo_frames_t FifoBuffer::readNow(void *buffer, fifo_frames_t numFrames) {
184    mLastReadSize = numFrames;
185    fifo_frames_t framesLeft = numFrames;
186    fifo_frames_t framesRead = read(buffer, numFrames);
187    framesLeft -= framesRead;
188    mFramesReadCount += framesRead;
189    mFramesUnderrunCount += framesLeft;
190    // Zero out any samples we could not set.
191    if (framesLeft > 0) {
192        mUnderrunCount++;
193        int32_t bytesToZero = convertFramesToBytes(framesLeft);
194        memset(buffer, 0, bytesToZero);
195    }
196
197    return framesRead;
198}
199
200fifo_frames_t FifoBuffer::getThreshold() {
201    return mFifo->getThreshold();
202}
203
204void FifoBuffer::setThreshold(fifo_frames_t threshold) {
205    mFifo->setThreshold(threshold);
206}
207
208fifo_frames_t FifoBuffer::getBufferCapacityInFrames() {
209    return mFifo->getCapacity();
210}
211
212