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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 #define LOG_TAG "FifoControllerBase"
18 //#define LOG_NDEBUG 0
19 #include <utils/Log.h>
20 
21 #include <stdint.h>
22 #include "FifoControllerBase.h"
23 
24 using namespace android;  // TODO just import names needed
25 
FifoControllerBase(fifo_frames_t capacity,fifo_frames_t threshold)26 FifoControllerBase::FifoControllerBase(fifo_frames_t capacity, fifo_frames_t threshold)
27         : mCapacity(capacity)
28         , mThreshold(threshold)
29 {
30 }
31 
~FifoControllerBase()32 FifoControllerBase::~FifoControllerBase() {
33 }
34 
getFullFramesAvailable()35 fifo_frames_t FifoControllerBase::getFullFramesAvailable() {
36     return (fifo_frames_t) (getWriteCounter() - getReadCounter());
37 }
38 
getReadIndex()39 fifo_frames_t FifoControllerBase::getReadIndex() {
40     // % works with non-power of two sizes
41     return (fifo_frames_t) ((uint64_t)getReadCounter() % mCapacity);
42 }
43 
advanceReadIndex(fifo_frames_t numFrames)44 void FifoControllerBase::advanceReadIndex(fifo_frames_t numFrames) {
45     setReadCounter(getReadCounter() + numFrames);
46 }
47 
getEmptyFramesAvailable()48 fifo_frames_t FifoControllerBase::getEmptyFramesAvailable() {
49     return (int32_t)(mThreshold - getFullFramesAvailable());
50 }
51 
getWriteIndex()52 fifo_frames_t FifoControllerBase::getWriteIndex() {
53     // % works with non-power of two sizes
54     return (fifo_frames_t) ((uint64_t)getWriteCounter() % mCapacity);
55 }
56 
advanceWriteIndex(fifo_frames_t numFrames)57 void FifoControllerBase::advanceWriteIndex(fifo_frames_t numFrames) {
58     setWriteCounter(getWriteCounter() + numFrames);
59 }
60 
setThreshold(fifo_frames_t threshold)61 void FifoControllerBase::setThreshold(fifo_frames_t threshold) {
62     if (threshold > mCapacity) {
63         threshold = mCapacity;
64     } else if (threshold < 0) {
65         threshold = 0;
66     }
67     mThreshold = threshold;
68 }
69