127 lines
5.2 KiB
C++
127 lines
5.2 KiB
C++
/*
|
|
File: CARingBuffer.h
|
|
Abstract: Part of CoreAudio Utility Classes
|
|
Version: 1.1
|
|
|
|
Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple
|
|
Inc. ("Apple") in consideration of your agreement to the following
|
|
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
|
|
redistribute this Apple software.
|
|
|
|
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;
|
|
provided that if you redistribute the Apple Software in its entirety and
|
|
without modifications, you must retain this notice and the following
|
|
text and disclaimers in all such redistributions of the Apple Software.
|
|
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
|
|
works in which the Apple Software may be incorporated.
|
|
|
|
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,
|
|
MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
|
|
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.
|
|
|
|
*/
|
|
#if !defined(__COREAUDIO_USE_FLAT_INCLUDES__)
|
|
#include <CoreAudio/CoreAudioTypes.h>
|
|
#else
|
|
#include <CoreAudioTypes.h>
|
|
#endif
|
|
|
|
|
|
#ifndef CARingBuffer_Header
|
|
#define CARingBuffer_Header
|
|
|
|
enum {
|
|
kCARingBufferError_OK = 0,
|
|
kCARingBufferError_TooMuch = 3, // fetch start time is earlier than buffer start time and fetch end time is later than buffer end time
|
|
kCARingBufferError_CPUOverload = 4 // the reader is unable to get enough CPU cycles to capture a consistent snapshot of the time bounds
|
|
};
|
|
|
|
typedef SInt32 CARingBufferError;
|
|
|
|
const UInt32 kGeneralRingTimeBoundsQueueSize = 32;
|
|
const UInt32 kGeneralRingTimeBoundsQueueMask = kGeneralRingTimeBoundsQueueSize - 1;
|
|
|
|
class CARingBuffer {
|
|
public:
|
|
typedef SInt64 SampleTime;
|
|
|
|
CARingBuffer();
|
|
~CARingBuffer();
|
|
|
|
void Allocate(int nChannels, UInt32 bytesPerFrame, UInt32 capacityFrames);
|
|
// capacityFrames will be rounded up to a power of 2
|
|
void Deallocate();
|
|
|
|
CARingBufferError Store(const AudioBufferList *abl, UInt32 nFrames, SampleTime frameNumber);
|
|
// Copy nFrames of data into the ring buffer at the specified sample time.
|
|
// The sample time should normally increase sequentially, though gaps
|
|
// are filled with zeroes. A sufficiently large gap effectively empties
|
|
// the buffer before storing the new data.
|
|
|
|
// If frameNumber is less than the previous frame number, the behavior is undefined.
|
|
|
|
// Return false for failure (buffer not large enough).
|
|
|
|
CARingBufferError Fetch(AudioBufferList *abl, UInt32 nFrames, SampleTime frameNumber);
|
|
// will alter mNumDataBytes of the buffers
|
|
|
|
CARingBufferError GetTimeBounds(SampleTime &startTime, SampleTime &endTime);
|
|
|
|
protected:
|
|
|
|
int FrameOffset(SampleTime frameNumber) { return (frameNumber & mCapacityFramesMask) * mBytesPerFrame; }
|
|
|
|
CARingBufferError ClipTimeBounds(SampleTime& startRead, SampleTime& endRead);
|
|
|
|
// these should only be called from Store.
|
|
SampleTime StartTime() const { return mTimeBoundsQueue[mTimeBoundsQueuePtr & kGeneralRingTimeBoundsQueueMask].mStartTime; }
|
|
SampleTime EndTime() const { return mTimeBoundsQueue[mTimeBoundsQueuePtr & kGeneralRingTimeBoundsQueueMask].mEndTime; }
|
|
void SetTimeBounds(SampleTime startTime, SampleTime endTime);
|
|
|
|
protected:
|
|
Byte ** mBuffers; // allocated in one chunk of memory
|
|
int mNumberChannels;
|
|
UInt32 mBytesPerFrame; // within one deinterleaved channel
|
|
UInt32 mCapacityFrames; // per channel, must be a power of 2
|
|
UInt32 mCapacityFramesMask;
|
|
UInt32 mCapacityBytes; // per channel
|
|
|
|
// range of valid sample time in the buffer
|
|
typedef struct {
|
|
volatile SampleTime mStartTime;
|
|
volatile SampleTime mEndTime;
|
|
volatile UInt32 mUpdateCounter;
|
|
} TimeBounds;
|
|
|
|
CARingBuffer::TimeBounds mTimeBoundsQueue[kGeneralRingTimeBoundsQueueSize];
|
|
UInt32 mTimeBoundsQueuePtr;
|
|
};
|
|
|
|
|
|
|
|
#endif
|