src/fifo/FifoControllerBase.cpp

/*
 * Copyright 2015 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.
 */

#include "FifoControllerBase.h"

#include <cassert>
#include <sys/types.h>
#include "FifoControllerBase.h"

#include "common/OboeDebug.h"

namespace oboe {

FifoControllerBase::FifoControllerBase(uint32_t totalFrames, uint32_t threshold)
        : mTotalFrames(totalFrames)
        , mThreshold(threshold)
{
    // numFrames must be a power of 2
//    assert((totalFrames & (totalFrames - 1)) == 0);
//    mSmallMask = totalFrames - 1;
}

FifoControllerBase::~FifoControllerBase() {
}

int32_t FifoControllerBase::getFullFramesAvailable() {
//    LOGD("getFullFramesAvailable - writeCounter = %d, readCounter() = %d",
//         (int)getWriteCounter(), (int) getReadCounter());
    return (int32_t) (getWriteCounter() - getReadCounter());
}

uint32_t FifoControllerBase::getReadIndex() {
//    return ((uint32_t) getReadCounter()) & mSmallMask;
    return (uint32_t) (getReadCounter() % mTotalFrames);
}

void FifoControllerBase::advanceReadIndex(int numFrames) {
    setReadCounter(getReadCounter() + numFrames);
}

int32_t FifoControllerBase::getEmptyFramesAvailable() {
    int32_t fullFramesAvailable = getFullFramesAvailable();
    int32_t available = (int32_t)(mThreshold - fullFramesAvailable);
//    LOGD("getEmptyFramesAvailable - full = %d, threshold = %u, available = %d",
//         fullFramesAvailable, mThreshold, available);
    return available;
}

uint32_t FifoControllerBase::getWriteIndex() {
//    return ((uint32_t) getWriteCounter()) & mSmallMask;
    return (uint32_t) (getWriteCounter() % mTotalFrames); // % works with non-power of two sizes
}

void FifoControllerBase::advanceWriteIndex(uint32_t numFrames) {
    setWriteCounter(getWriteCounter() + numFrames);
}

void FifoControllerBase::setThreshold(uint32_t threshold) {
    mThreshold = threshold;
}

} // namespace oboe