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Diffstat (limited to 'pd/portaudio/src/common/pa_ringbuffer.c')
| -rw-r--r-- | pd/portaudio/src/common/pa_ringbuffer.c | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/pd/portaudio/src/common/pa_ringbuffer.c b/pd/portaudio/src/common/pa_ringbuffer.c new file mode 100644 index 00000000..84465cff --- /dev/null +++ b/pd/portaudio/src/common/pa_ringbuffer.c @@ -0,0 +1,285 @@ +/* + * $Id: pa_ringbuffer.c,v 1.1 2007-08-18 23:52:12 millerpuckette Exp $ + * 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 + * 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. + */ + +/* + * The text above constitutes the entire PortAudio license; however, + * the PortAudio community also makes the following non-binding requests: + * + * Any person wishing to distribute modifications to the Software is + * requested to send the modifications to the original developer so that + * they can be incorporated into the canonical version. It is also + * requested that these non-binding requests be included along with the + * license above. + */ + +/** + @file + @ingroup common_src +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <math.h> +#include "pa_ringbuffer.h" +#include <string.h> + +/**************** + * First, we'll define some memory barrier primitives based on the system. + * right now only OS X, FreeBSD, and Linux are supported. In addition to providing + * memory barriers, these functions should ensure that data cached in registers + * is written out to cache where it can be snooped by other CPUs. (ie, the volatile + * keyword should not be required) + * + * the primitives that must be defined are: + * + * PaUtil_FullMemoryBarrier() + * PaUtil_ReadMemoryBarrier() + * PaUtil_WriteMemoryBarrier() + * + ****************/ + +#if defined(__APPLE__) +# include <libkern/OSAtomic.h> + /* Here are the memory barrier functions. Mac OS X only provides + full memory barriers, so the three types of barriers are the same, + however, these barriers are superior to compiler-based ones. */ +# define PaUtil_FullMemoryBarrier() OSMemoryBarrier() +# define PaUtil_ReadMemoryBarrier() OSMemoryBarrier() +# define PaUtil_WriteMemoryBarrier() OSMemoryBarrier() +#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 +#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 + +/*************************************************************************** + * Initialize FIFO. + * numBytes must be power of 2, returns -1 if not. + */ +long PaUtil_InitializeRingBuffer( PaUtilRingBuffer *rbuf, long numBytes, void *dataPtr ) +{ + if( ((numBytes-1) & numBytes) != 0) return -1; /* Not Power of two. */ + rbuf->bufferSize = numBytes; + rbuf->buffer = (char *)dataPtr; + PaUtil_FlushRingBuffer( rbuf ); + rbuf->bigMask = (numBytes*2)-1; + rbuf->smallMask = (numBytes)-1; + return 0; +} + +/*************************************************************************** +** Return number of bytes available for reading. */ +long PaUtil_GetRingBufferReadAvailable( PaUtilRingBuffer *rbuf ) +{ + PaUtil_ReadMemoryBarrier(); + return ( (rbuf->writeIndex - rbuf->readIndex) & rbuf->bigMask ); +} +/*************************************************************************** +** Return number of bytes available for writing. */ +long PaUtil_GetRingBufferWriteAvailable( PaUtilRingBuffer *rbuf ) +{ + /* Since we are calling PaUtil_GetRingBufferReadAvailable, we don't need an aditional MB */ + return ( rbuf->bufferSize - PaUtil_GetRingBufferReadAvailable(rbuf)); +} + +/*************************************************************************** +** Clear buffer. Should only be called when buffer is NOT being read. */ +void PaUtil_FlushRingBuffer( PaUtilRingBuffer *rbuf ) +{ + rbuf->writeIndex = rbuf->readIndex = 0; +} + +/*************************************************************************** +** 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 numBytes, whichever is smaller. +*/ +long PaUtil_GetRingBufferWriteRegions( PaUtilRingBuffer *rbuf, long numBytes, + void **dataPtr1, long *sizePtr1, + void **dataPtr2, long *sizePtr2 ) +{ + long index; + long available = PaUtil_GetRingBufferWriteAvailable( rbuf ); + if( numBytes > available ) numBytes = available; + /* Check to see if write is not contiguous. */ + index = rbuf->writeIndex & rbuf->smallMask; + if( (index + numBytes) > rbuf->bufferSize ) + { + /* Write data in two blocks that wrap the buffer. */ + long firstHalf = rbuf->bufferSize - index; + *dataPtr1 = &rbuf->buffer[index]; + *sizePtr1 = firstHalf; + *dataPtr2 = &rbuf->buffer[0]; + *sizePtr2 = numBytes - firstHalf; + } + else + { + *dataPtr1 = &rbuf->buffer[index]; + *sizePtr1 = numBytes; + *dataPtr2 = NULL; + *sizePtr2 = 0; + } + return numBytes; +} + + +/*************************************************************************** +*/ +long PaUtil_AdvanceRingBufferWriteIndex( PaUtilRingBuffer *rbuf, long numBytes ) +{ + /* we need to ensure that previous writes are seen before we update the write index */ + PaUtil_WriteMemoryBarrier(); + return rbuf->writeIndex = (rbuf->writeIndex + numBytes) & rbuf->bigMask; +} + +/*************************************************************************** +** 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 written or numBytes, whichever is smaller. +*/ +long PaUtil_GetRingBufferReadRegions( PaUtilRingBuffer *rbuf, long numBytes, + void **dataPtr1, long *sizePtr1, + void **dataPtr2, long *sizePtr2 ) +{ + long index; + long available = PaUtil_GetRingBufferReadAvailable( rbuf ); + if( numBytes > available ) numBytes = available; + /* Check to see if read is not contiguous. */ + index = rbuf->readIndex & rbuf->smallMask; + if( (index + numBytes) > rbuf->bufferSize ) + { + /* Write data in two blocks that wrap the buffer. */ + long firstHalf = rbuf->bufferSize - index; + *dataPtr1 = &rbuf->buffer[index]; + *sizePtr1 = firstHalf; + *dataPtr2 = &rbuf->buffer[0]; + *sizePtr2 = numBytes - firstHalf; + } + else + { + *dataPtr1 = &rbuf->buffer[index]; + *sizePtr1 = numBytes; + *dataPtr2 = NULL; + *sizePtr2 = 0; + } + return numBytes; +} +/*************************************************************************** +*/ +long PaUtil_AdvanceRingBufferReadIndex( PaUtilRingBuffer *rbuf, long numBytes ) +{ + /* we need to ensure that previous writes are always seen before updating the index. */ + PaUtil_WriteMemoryBarrier(); + return rbuf->readIndex = (rbuf->readIndex + numBytes) & rbuf->bigMask; +} + +/*************************************************************************** +** Return bytes written. */ +long PaUtil_WriteRingBuffer( PaUtilRingBuffer *rbuf, const void *data, long numBytes ) +{ + long size1, size2, numWritten; + void *data1, *data2; + numWritten = PaUtil_GetRingBufferWriteRegions( rbuf, numBytes, &data1, &size1, &data2, &size2 ); + if( size2 > 0 ) + { + + memcpy( data1, data, size1 ); + data = ((char *)data) + size1; + memcpy( data2, data, size2 ); + } + else + { + memcpy( data1, data, size1 ); + } + PaUtil_AdvanceRingBufferWriteIndex( rbuf, numWritten ); + return numWritten; +} + +/*************************************************************************** +** Return bytes read. */ +long PaUtil_ReadRingBuffer( PaUtilRingBuffer *rbuf, void *data, long numBytes ) +{ + long size1, size2, numRead; + void *data1, *data2; + numRead = PaUtil_GetRingBufferReadRegions( rbuf, numBytes, &data1, &size1, &data2, &size2 ); + if( size2 > 0 ) + { + memcpy( data, data1, size1 ); + data = ((char *)data) + size1; + memcpy( data, data2, size2 ); + } + else + { + memcpy( data, data1, size1 ); + } + PaUtil_AdvanceRingBufferReadIndex( rbuf, numRead ); + return numRead; +} |