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SDR-DAB_dab-cmdline/ringbuffer.h

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#
/*
* $Id: pa_ringbuffer.c 1738 2011-08-18 11:47:28Z rossb $
* Portable Audio I/O Library
* Ring Buffer utility.
*
* Author: Phil Burk, http://www.softsynth.com
* modified for SMP safety on Mac OS X by Bjorn Roche
* modified for SMP safety on Linux by Leland Lucius
* also, allowed for const where possible
* modified for multiple-byte-sized data elements by Sven Fischer
*
* Note that this is safe only for a single-thread reader and a
* single-thread writer.
*
* This program uses the PortAudio Portable Audio Library.
* For more information see: http://www.portaudio.com
* Copyright (c) 1999-2000 Ross Bencina and Phil Burk
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
*
* Copyright (C) 2008, 2009, 2010
* Jan van Katwijk (J.vanKatwijk@gmail.com)
* Lazy Chair Computing
*
* The ringbuffer here is a rewrite of the ringbuffer used in the PA code
* All rights remain with their owners
* This file is part of the SDR-J.
* Many of the ideas as implemented in SDR-J are derived from
* other work, made available through the GNU general Public License.
* All copyrights of the original authors are recognized.
*
* SDR-J is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* SDR-J is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with ESDR; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __RINGBUFFER
#define __RINGBUFFER
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
/*
* a simple ringbuffer, lockfree, however only for a
* single reader and a single writer.
* Mostly used for getting samples from or to the soundcard
*/
#if defined(__APPLE__)
# include <atomic>
# define PaUtil_FullMemoryBarrier() std::atomic_thread_fence(std::memory_order_seq_cst)
# define PaUtil_ReadMemoryBarrier() std::atomic_thread_fence(std::memory_order_seq_cst)
# define PaUtil_WriteMemoryBarrier() std::atomic_thread_fence(std::memory_order_seq_cst)
#elif defined(__GNUC__)
/* GCC >= 4.1 has built-in intrinsics. We'll use those */
# if (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)
# define PaUtil_FullMemoryBarrier() __sync_synchronize()
# define PaUtil_ReadMemoryBarrier() __sync_synchronize()
# define PaUtil_WriteMemoryBarrier() __sync_synchronize()
/* as a fallback, GCC understands volatile asm and "memory" to mean it
* should not reorder memory read/writes */
# elif defined( __PPC__ )
# define PaUtil_FullMemoryBarrier() asm volatile("sync":::"memory")
# define PaUtil_ReadMemoryBarrier() asm volatile("sync":::"memory")
# define PaUtil_WriteMemoryBarrier() asm volatile("sync":::"memory")
# elif defined( __i386__ ) || defined( __i486__ ) || defined( __i586__ ) || defined( __i686__ ) || defined( __x86_64__ )
# define PaUtil_FullMemoryBarrier() asm volatile("mfence":::"memory")
# define PaUtil_ReadMemoryBarrier() asm volatile("lfence":::"memory")
# define PaUtil_WriteMemoryBarrier() asm volatile("sfence":::"memory")
# else
# ifdef ALLOW_SMP_DANGERS
# warning Memory barriers not defined on this system or system unknown
# warning For SMP safety, you should fix this.
# define PaUtil_FullMemoryBarrier()
# define PaUtil_ReadMemoryBarrier()
# define PaUtil_WriteMemoryBarrier()
# else
# error Memory barriers are not defined on this system. You can still compile by defining ALLOW_SMP_DANGERS, but SMP safety will not be guaranteed.
# endif
# endif
#elif defined(_MSC_VER)
# include <intrin.h>
# define PaUtil_FullMemoryBarrier() _mm_mfence()
# define PaUtil_ReadMemoryBarrier() _mm_mfence()
# define PaUtil_WriteMemoryBarrier() _mm_mfence()
#else
# ifdef ALLOW_SMP_DANGERS
# warning Memory barriers not defined on this system or system unknown
# warning For SMP safety, you should fix this.
# define PaUtil_FullMemoryBarrier()
# define PaUtil_ReadMemoryBarrier()
# define PaUtil_WriteMemoryBarrier()
# else
# error Memory barriers are not defined on this system. You can still compile by defining ALLOW_SMP_DANGERS, but SMP safety will not be guaranteed.
# endif
#endif
template <class elementtype>
class RingBuffer {
private:
uint32_t bufferSize;
volatile uint32_t writeIndex;
volatile uint32_t readIndex;
uint32_t bigMask;
uint32_t smallMask;
char *buffer;
public:
RingBuffer (uint32_t elementCount) {
if (((elementCount - 1) & elementCount) != 0)
elementCount = 2 * 16384; /* default */
bufferSize = elementCount;
buffer = new char [2 * bufferSize * sizeof (elementtype)];
writeIndex = 0;
readIndex = 0;
smallMask = (elementCount)- 1;
bigMask = (elementCount * 2) - 1;
}
~RingBuffer () {
delete[] buffer;
}
/*
* functions for checking available data for reading and space
* for writing
*/
int32_t GetRingBufferReadAvailable (void) {
return (writeIndex - readIndex) & bigMask;
}
int32_t ReadSpace (void){
return GetRingBufferReadAvailable ();
}
int32_t GetRingBufferWriteAvailable (void) {
return bufferSize - GetRingBufferReadAvailable ();
}
int32_t WriteSpace (void) {
return GetRingBufferWriteAvailable ();
}
void FlushRingBuffer () {
writeIndex = 0;
readIndex = 0;
}
/* ensure that previous writes are seen before we update the write index
(write after write)
*/
int32_t AdvanceRingBufferWriteIndex (int32_t elementCount) {
PaUtil_WriteMemoryBarrier();
return writeIndex = (writeIndex + elementCount) & bigMask;
}
/* ensure that previous reads (copies out of the ring buffer) are
* always completed before updating (writing) the read index.
* (write-after-read) => full barrier
*/
int32_t AdvanceRingBufferReadIndex (int32_t elementCount) {
PaUtil_FullMemoryBarrier();
return readIndex = (readIndex + elementCount) & bigMask;
}
/***************************************************************************
** Get address of region(s) to which we can write data.
** If the region is contiguous, size2 will be zero.
** If non-contiguous, size2 will be the size of second region.
** Returns room available to be written or elementCount, whichever is smaller.
*/
int32_t GetRingBufferWriteRegions (uint32_t elementCount,
void **dataPtr1, int32_t *sizePtr1,
void **dataPtr2, int32_t *sizePtr2 ) {
uint32_t index;
uint32_t available = GetRingBufferWriteAvailable ();
if (elementCount > available)
elementCount = available;
/* Check to see if write is not contiguous. */
index = writeIndex & smallMask;
if ((index + elementCount) > bufferSize ) {
/* Write data in two blocks that wrap the buffer. */
int32_t firstHalf = bufferSize - index;
*dataPtr1 = &buffer[index * sizeof(elementtype)];
*sizePtr1 = firstHalf;
*dataPtr2 = &buffer [0];
*sizePtr2 = elementCount - firstHalf;
}
else { // fits
*dataPtr1 = &buffer [index * sizeof(elementtype)];
*sizePtr1 = elementCount;
*dataPtr2 = NULL;
*sizePtr2 = 0;
}
if (available > 0)
PaUtil_FullMemoryBarrier(); /* (write-after-read) => full barrier */
return elementCount;
}
/***************************************************************************
** Get address of region(s) from which we can read data.
** If the region is contiguous, size2 will be zero.
** If non-contiguous, size2 will be the size of second region.
** Returns room available to be read or elementCount, whichever is smaller.
*/
int32_t GetRingBufferReadRegions (uint32_t elementCount,
void **dataPtr1, int32_t *sizePtr1,
void **dataPtr2, int32_t *sizePtr2) {
uint32_t index;
uint32_t available = GetRingBufferReadAvailable (); /* doesn't use memory barrier */
if (elementCount > available)
elementCount = available;
/* Check to see if read is not contiguous. */
index = readIndex & smallMask;
if ((index + elementCount) > bufferSize) {
/* Write data in two blocks that wrap the buffer. */
int32_t firstHalf = bufferSize - index;
*dataPtr1 = &buffer [index * sizeof(elementtype)];
*sizePtr1 = firstHalf;
*dataPtr2 = &buffer [0];
*sizePtr2 = elementCount - firstHalf;
}
else {
*dataPtr1 = &buffer [index * sizeof(elementtype)];
*sizePtr1 = elementCount;
*dataPtr2 = NULL;
*sizePtr2 = 0;
}
if (available)
PaUtil_ReadMemoryBarrier(); /* (read-after-read) => read barrier */
return elementCount;
}
int32_t putDataIntoBuffer (const void *data, int32_t elementCount) {
int32_t size1, size2, numWritten;
void *data1;
void *data2;
numWritten = GetRingBufferWriteRegions (elementCount,
&data1, &size1,
&data2, &size2 );
if (size2 > 0) {
memcpy (data1, data, size1 * sizeof(elementtype));
data = ((char *)data) + size1 * sizeof(elementtype);
memcpy (data2, data, size2 * sizeof(elementtype));
}
else
memcpy (data1, data, size1 * sizeof(elementtype));
AdvanceRingBufferWriteIndex (numWritten );
return numWritten;
}
int32_t getDataFromBuffer (void *data, int32_t elementCount ) {
int32_t size1, size2, numRead;
void *data1;
void *data2;
numRead = GetRingBufferReadRegions (elementCount,
&data1, &size1,
&data2, &size2 );
if (size2 > 0) {
memcpy (data, data1, size1 * sizeof(elementtype));
data = ((char *)data) + size1 * sizeof(elementtype);
memcpy (data, data2, size2 * sizeof(elementtype));
}
else
memcpy (data, data1, size1 * sizeof(elementtype));
AdvanceRingBufferReadIndex (numRead );
return numRead;
}
int32_t skipDataInBuffer (uint32_t n_values) {
// ensure that we have the correct read and write indices
PaUtil_FullMemoryBarrier ();
if (n_values > GetRingBufferReadAvailable ())
n_values = GetRingBufferReadAvailable ();
AdvanceRingBufferReadIndex (n_values);
return n_values;
}
};
#endif