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livetrax/libs/appleutility/CoreAudio/PublicUtility/CARingBuffer.cpp

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C++

/*
File: CARingBuffer.cpp
Abstract: CARingBuffer.h
Version: 1.1
Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple
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terms, and your use, installation, modification or redistribution of
this Apple software constitutes acceptance of these terms. If you do
not agree with these terms, please do not use, install, modify or
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In consideration of your agreement to abide by the following terms, and
subject to these terms, Apple grants you a personal, non-exclusive
license, under Apple's copyrights in this original Apple software (the
"Apple Software"), to use, reproduce, modify and redistribute the Apple
Software, with or without modifications, in source and/or binary forms;
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Neither the name, trademarks, service marks or logos of Apple Inc. may
be used to endorse or promote products derived from the Apple Software
without specific prior written permission from Apple. Except as
expressly stated in this notice, no other rights or licenses, express or
implied, are granted by Apple herein, including but not limited to any
patent rights that may be infringed by your derivative works or by other
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The Apple Software is provided by Apple on an "AS IS" basis. APPLE
MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
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AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
Copyright (C) 2014 Apple Inc. All Rights Reserved.
*/
#include "CARingBuffer.h"
#include "CABitOperations.h"
#include "CAAutoDisposer.h"
#include "CAAtomic.h"
#include <stdlib.h>
#include <string.h>
#include <algorithm>
#include <libkern/OSAtomic.h>
CARingBuffer::CARingBuffer() :
mBuffers(NULL), mNumberChannels(0), mCapacityFrames(0), mCapacityBytes(0)
{
}
CARingBuffer::~CARingBuffer()
{
Deallocate();
}
void CARingBuffer::Allocate(int nChannels, UInt32 bytesPerFrame, UInt32 capacityFrames)
{
Deallocate();
capacityFrames = NextPowerOfTwo(capacityFrames);
mNumberChannels = nChannels;
mBytesPerFrame = bytesPerFrame;
mCapacityFrames = capacityFrames;
mCapacityFramesMask = capacityFrames - 1;
mCapacityBytes = bytesPerFrame * capacityFrames;
// put everything in one memory allocation, first the pointers, then the deinterleaved channels
UInt32 allocSize = (mCapacityBytes + sizeof(Byte *)) * nChannels;
Byte *p = (Byte *)CA_malloc(allocSize);
memset(p, 0, allocSize);
mBuffers = (Byte **)p;
p += nChannels * sizeof(Byte *);
for (int i = 0; i < nChannels; ++i) {
mBuffers[i] = p;
p += mCapacityBytes;
}
for (UInt32 i = 0; i<kGeneralRingTimeBoundsQueueSize; ++i)
{
mTimeBoundsQueue[i].mStartTime = 0;
mTimeBoundsQueue[i].mEndTime = 0;
mTimeBoundsQueue[i].mUpdateCounter = 0;
}
mTimeBoundsQueuePtr = 0;
}
void CARingBuffer::Deallocate()
{
if (mBuffers) {
free(mBuffers);
mBuffers = NULL;
}
mNumberChannels = 0;
mCapacityBytes = 0;
mCapacityFrames = 0;
}
inline void ZeroRange(Byte **buffers, int nchannels, int offset, int nbytes)
{
while (--nchannels >= 0) {
memset(*buffers + offset, 0, nbytes);
++buffers;
}
}
inline void StoreABL(Byte **buffers, int destOffset, const AudioBufferList *abl, int srcOffset, int nbytes)
{
int nchannels = abl->mNumberBuffers;
const AudioBuffer *src = abl->mBuffers;
while (--nchannels >= 0) {
if (srcOffset > (int)src->mDataByteSize) continue;
memcpy(*buffers + destOffset, (Byte *)src->mData + srcOffset, std::min(nbytes, (int)src->mDataByteSize - srcOffset));
++buffers;
++src;
}
}
inline void FetchABL(AudioBufferList *abl, int destOffset, Byte **buffers, int srcOffset, int nbytes)
{
int nchannels = abl->mNumberBuffers;
AudioBuffer *dest = abl->mBuffers;
while (--nchannels >= 0) {
if (destOffset > (int)dest->mDataByteSize) continue;
memcpy((Byte *)dest->mData + destOffset, *buffers + srcOffset, std::min(nbytes, (int)dest->mDataByteSize - destOffset));
++buffers;
++dest;
}
}
inline void ZeroABL(AudioBufferList *abl, int destOffset, int nbytes)
{
int nBuffers = abl->mNumberBuffers;
AudioBuffer *dest = abl->mBuffers;
while (--nBuffers >= 0) {
if (destOffset > (int)dest->mDataByteSize) continue;
memset((Byte *)dest->mData + destOffset, 0, std::min(nbytes, (int)dest->mDataByteSize - destOffset));
++dest;
}
}
CARingBufferError CARingBuffer::Store(const AudioBufferList *abl, UInt32 framesToWrite, SampleTime startWrite)
{
if (framesToWrite == 0)
return kCARingBufferError_OK;
if (framesToWrite > mCapacityFrames)
return kCARingBufferError_TooMuch; // too big!
SampleTime endWrite = startWrite + framesToWrite;
if (startWrite < EndTime()) {
// going backwards, throw everything out
SetTimeBounds(startWrite, startWrite);
} else if (endWrite - StartTime() <= mCapacityFrames) {
// the buffer has not yet wrapped and will not need to
} else {
// advance the start time past the region we are about to overwrite
SampleTime newStart = endWrite - mCapacityFrames; // one buffer of time behind where we're writing
SampleTime newEnd = std::max(newStart, EndTime());
SetTimeBounds(newStart, newEnd);
}
// write the new frames
Byte **buffers = mBuffers;
int nchannels = mNumberChannels;
int offset0, offset1, nbytes;
SampleTime curEnd = EndTime();
if (startWrite > curEnd) {
// we are skipping some samples, so zero the range we are skipping
offset0 = FrameOffset(curEnd);
offset1 = FrameOffset(startWrite);
if (offset0 < offset1)
ZeroRange(buffers, nchannels, offset0, offset1 - offset0);
else {
ZeroRange(buffers, nchannels, offset0, mCapacityBytes - offset0);
ZeroRange(buffers, nchannels, 0, offset1);
}
offset0 = offset1;
} else {
offset0 = FrameOffset(startWrite);
}
offset1 = FrameOffset(endWrite);
if (offset0 < offset1)
StoreABL(buffers, offset0, abl, 0, offset1 - offset0);
else {
nbytes = mCapacityBytes - offset0;
StoreABL(buffers, offset0, abl, 0, nbytes);
StoreABL(buffers, 0, abl, nbytes, offset1);
}
// now update the end time
SetTimeBounds(StartTime(), endWrite);
return kCARingBufferError_OK; // success
}
void CARingBuffer::SetTimeBounds(SampleTime startTime, SampleTime endTime)
{
UInt32 nextPtr = mTimeBoundsQueuePtr + 1;
UInt32 index = nextPtr & kGeneralRingTimeBoundsQueueMask;
mTimeBoundsQueue[index].mStartTime = startTime;
mTimeBoundsQueue[index].mEndTime = endTime;
mTimeBoundsQueue[index].mUpdateCounter = nextPtr;
CAAtomicCompareAndSwap32Barrier(mTimeBoundsQueuePtr, mTimeBoundsQueuePtr + 1, (SInt32*)&mTimeBoundsQueuePtr);
}
CARingBufferError CARingBuffer::GetTimeBounds(SampleTime &startTime, SampleTime &endTime)
{
for (int i=0; i<8; ++i) // fail after a few tries.
{
UInt32 curPtr = mTimeBoundsQueuePtr;
UInt32 index = curPtr & kGeneralRingTimeBoundsQueueMask;
CARingBuffer::TimeBounds* bounds = mTimeBoundsQueue + index;
startTime = bounds->mStartTime;
endTime = bounds->mEndTime;
UInt32 newPtr = bounds->mUpdateCounter;
if (newPtr == curPtr)
return kCARingBufferError_OK;
}
return kCARingBufferError_CPUOverload;
}
CARingBufferError CARingBuffer::ClipTimeBounds(SampleTime& startRead, SampleTime& endRead)
{
SampleTime startTime, endTime;
CARingBufferError err = GetTimeBounds(startTime, endTime);
if (err) return err;
if (startRead > endTime || endRead < startTime) {
endRead = startRead;
return kCARingBufferError_OK;
}
startRead = std::max(startRead, startTime);
endRead = std::min(endRead, endTime);
endRead = std::max(endRead, startRead);
return kCARingBufferError_OK; // success
}
CARingBufferError CARingBuffer::Fetch(AudioBufferList *abl, UInt32 nFrames, SampleTime startRead)
{
if (nFrames == 0)
return kCARingBufferError_OK;
startRead = std::max(0LL, startRead);
SampleTime endRead = startRead + nFrames;
SampleTime startRead0 = startRead;
SampleTime endRead0 = endRead;
CARingBufferError err = ClipTimeBounds(startRead, endRead);
if (err) return err;
if (startRead == endRead) {
ZeroABL(abl, 0, nFrames * mBytesPerFrame);
return kCARingBufferError_OK;
}
SInt32 byteSize = (SInt32)((endRead - startRead) * mBytesPerFrame);
SInt32 destStartByteOffset = std::max((SInt32)0, (SInt32)((startRead - startRead0) * mBytesPerFrame));
if (destStartByteOffset > 0) {
ZeroABL(abl, 0, std::min((SInt32)(nFrames * mBytesPerFrame), destStartByteOffset));
}
SInt32 destEndSize = std::max((SInt32)0, (SInt32)(endRead0 - endRead));
if (destEndSize > 0) {
ZeroABL(abl, destStartByteOffset + byteSize, destEndSize * mBytesPerFrame);
}
Byte **buffers = mBuffers;
int offset0 = FrameOffset(startRead);
int offset1 = FrameOffset(endRead);
int nbytes;
if (offset0 < offset1) {
nbytes = offset1 - offset0;
FetchABL(abl, destStartByteOffset, buffers, offset0, nbytes);
} else {
nbytes = mCapacityBytes - offset0;
FetchABL(abl, destStartByteOffset, buffers, offset0, nbytes);
FetchABL(abl, destStartByteOffset + nbytes, buffers, 0, offset1);
nbytes += offset1;
}
int nchannels = abl->mNumberBuffers;
AudioBuffer *dest = abl->mBuffers;
while (--nchannels >= 0)
{
dest->mDataByteSize = nbytes;
dest++;
}
return noErr;
}