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ea3e61f3d8
git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@4175 d0543943-73ff-0310-b7d9-9358b9ac24b2
286 lines
10 KiB
C
286 lines
10 KiB
C
/*
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* $Id: pa_ringbuffer.c 1164 2006-12-21 15:34:50Z bjornroche $
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* Portable Audio I/O Library
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* Ring Buffer utility.
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*
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* Author: Phil Burk, http://www.softsynth.com
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* modified for SMP safety on Mac OS X by Bjorn Roche
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* modified for SMP safety on Linux by Leland Lucius
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* also, allowed for const where possible
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* Note that this is safe only for a single-thread reader and a
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* single-thread writer.
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*
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* This program uses the PortAudio Portable Audio Library.
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* For more information see: http://www.portaudio.com
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* Copyright (c) 1999-2000 Ross Bencina and Phil Burk
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files
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* (the "Software"), to deal in the Software without restriction,
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* including without limitation the rights to use, copy, modify, merge,
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* publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
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* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
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* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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/*
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* The text above constitutes the entire PortAudio license; however,
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* the PortAudio community also makes the following non-binding requests:
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*
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* Any person wishing to distribute modifications to the Software is
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* requested to send the modifications to the original developer so that
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* they can be incorporated into the canonical version. It is also
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* requested that these non-binding requests be included along with the
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* license above.
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*/
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/**
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@file
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@ingroup common_src
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include "pa_ringbuffer.h"
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#include <string.h>
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/****************
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* First, we'll define some memory barrier primitives based on the system.
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* right now only OS X, FreeBSD, and Linux are supported. In addition to providing
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* memory barriers, these functions should ensure that data cached in registers
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* is written out to cache where it can be snooped by other CPUs. (ie, the volatile
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* keyword should not be required)
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*
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* the primitives that must be defined are:
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*
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* PaUtil_FullMemoryBarrier()
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* PaUtil_ReadMemoryBarrier()
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* PaUtil_WriteMemoryBarrier()
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*
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****************/
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#if defined(__VIA_HACK__)
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#define NO_BARRIER
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#endif
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#if defined(NO_BARRIER)
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# define PaUtil_FullMemoryBarrier()
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# define PaUtil_ReadMemoryBarrier()
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# define PaUtil_WriteMemoryBarrier()
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#else
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#if defined(__APPLE__) //|| defined(__FreeBSD__)
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# include <libkern/OSAtomic.h>
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/* Here are the memory barrier functions. Mac OS X and FreeBSD only provide
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full memory barriers, so the three types of barriers are the same. */
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# define PaUtil_FullMemoryBarrier() OSMemoryBarrier()
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# define PaUtil_ReadMemoryBarrier() OSMemoryBarrier()
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# define PaUtil_WriteMemoryBarrier() OSMemoryBarrier()
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#elif defined(__GNUC__)
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/* GCC understands volatile asm and "memory" to mean it
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* should not reorder memory read/writes */
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# if defined( __PPC__ )
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# define PaUtil_FullMemoryBarrier() asm volatile("sync":::"memory")
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# define PaUtil_ReadMemoryBarrier() asm volatile("sync":::"memory")
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# define PaUtil_WriteMemoryBarrier() asm volatile("sync":::"memory")
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# elif defined( __i386__ ) || defined( __i486__ ) || defined( __i586__ ) || defined( __i686__ ) || defined(__x86_64__)
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# define PaUtil_FullMemoryBarrier() asm volatile("mfence":::"memory")
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# define PaUtil_ReadMemoryBarrier() asm volatile("lfence":::"memory")
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# define PaUtil_WriteMemoryBarrier() asm volatile("sfence":::"memory")
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# else
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# define PaUtil_FullMemoryBarrier()
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# define PaUtil_ReadMemoryBarrier()
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# define PaUtil_WriteMemoryBarrier()
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# endif
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#elif defined(_MSC_VER)
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# include <intrin.h>
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# pragma intrinsic(_ReadWriteBarrier)
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# pragma intrinsic(_ReadBarrier)
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# pragma intrinsic(_WriteBarrier)
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# define PaUtil_FullMemoryBarrier() _ReadWriteBarrier()
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# define PaUtil_ReadMemoryBarrier() _ReadBarrier()
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# define PaUtil_WriteMemoryBarrier() _WriteBarrier()
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#else
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# define PaUtil_FullMemoryBarrier()
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# define PaUtil_ReadMemoryBarrier()
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# define PaUtil_WriteMemoryBarrier()
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#endif
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#endif
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/***************************************************************************
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* Initialize FIFO.
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* numBytes must be power of 2, returns -1 if not.
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*/
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long PaUtil_InitializeRingBuffer( PaUtilRingBuffer *rbuf, long numBytes, void *dataPtr )
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{
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if( ((numBytes-1) & numBytes) != 0) return -1; /* Not Power of two. */
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rbuf->bufferSize = numBytes;
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rbuf->buffer = (char *)dataPtr;
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PaUtil_FlushRingBuffer( rbuf );
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rbuf->bigMask = (numBytes*2)-1;
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rbuf->smallMask = (numBytes)-1;
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return 0;
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}
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/***************************************************************************
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** Return number of bytes available for reading. */
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long PaUtil_GetRingBufferReadAvailable( PaUtilRingBuffer *rbuf )
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{
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PaUtil_ReadMemoryBarrier();
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return ( (rbuf->writeIndex - rbuf->readIndex) & rbuf->bigMask );
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}
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/***************************************************************************
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** Return number of bytes available for writing. */
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long PaUtil_GetRingBufferWriteAvailable( PaUtilRingBuffer *rbuf )
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{
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/* Since we are calling PaUtil_GetRingBufferReadAvailable, we don't need an aditional MB */
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return ( rbuf->bufferSize - PaUtil_GetRingBufferReadAvailable(rbuf));
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}
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/***************************************************************************
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** Clear buffer. Should only be called when buffer is NOT being read. */
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void PaUtil_FlushRingBuffer( PaUtilRingBuffer *rbuf )
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{
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rbuf->writeIndex = rbuf->readIndex = 0;
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}
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/***************************************************************************
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** Get address of region(s) to which we can write data.
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** If the region is contiguous, size2 will be zero.
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** If non-contiguous, size2 will be the size of second region.
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** Returns room available to be written or numBytes, whichever is smaller.
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*/
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long PaUtil_GetRingBufferWriteRegions( PaUtilRingBuffer *rbuf, long numBytes,
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void **dataPtr1, long *sizePtr1,
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void **dataPtr2, long *sizePtr2 )
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{
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long index;
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long available = PaUtil_GetRingBufferWriteAvailable( rbuf );
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if( numBytes > available ) numBytes = available;
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/* Check to see if write is not contiguous. */
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index = rbuf->writeIndex & rbuf->smallMask;
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if( (index + numBytes) > rbuf->bufferSize )
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{
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/* Write data in two blocks that wrap the buffer. */
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long firstHalf = rbuf->bufferSize - index;
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*dataPtr1 = &rbuf->buffer[index];
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*sizePtr1 = firstHalf;
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*dataPtr2 = &rbuf->buffer[0];
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*sizePtr2 = numBytes - firstHalf;
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}
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else
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{
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*dataPtr1 = &rbuf->buffer[index];
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*sizePtr1 = numBytes;
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*dataPtr2 = NULL;
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*sizePtr2 = 0;
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}
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return numBytes;
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}
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/***************************************************************************
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*/
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long PaUtil_AdvanceRingBufferWriteIndex( PaUtilRingBuffer *rbuf, long numBytes )
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{
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/* we need to ensure that previous writes are seen before we update the write index */
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PaUtil_WriteMemoryBarrier();
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return rbuf->writeIndex = (rbuf->writeIndex + numBytes) & rbuf->bigMask;
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}
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/***************************************************************************
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** Get address of region(s) from which we can read data.
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** If the region is contiguous, size2 will be zero.
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** If non-contiguous, size2 will be the size of second region.
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** Returns room available to be written or numBytes, whichever is smaller.
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*/
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long PaUtil_GetRingBufferReadRegions( PaUtilRingBuffer *rbuf, long numBytes,
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void **dataPtr1, long *sizePtr1,
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void **dataPtr2, long *sizePtr2 )
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{
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long index;
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long available = PaUtil_GetRingBufferReadAvailable( rbuf );
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if( numBytes > available ) numBytes = available;
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/* Check to see if read is not contiguous. */
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index = rbuf->readIndex & rbuf->smallMask;
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if( (index + numBytes) > rbuf->bufferSize )
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{
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/* Write data in two blocks that wrap the buffer. */
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long firstHalf = rbuf->bufferSize - index;
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*dataPtr1 = &rbuf->buffer[index];
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*sizePtr1 = firstHalf;
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*dataPtr2 = &rbuf->buffer[0];
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*sizePtr2 = numBytes - firstHalf;
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}
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else
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{
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*dataPtr1 = &rbuf->buffer[index];
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*sizePtr1 = numBytes;
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*dataPtr2 = NULL;
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*sizePtr2 = 0;
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}
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return numBytes;
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}
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/***************************************************************************
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*/
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long PaUtil_AdvanceRingBufferReadIndex( PaUtilRingBuffer *rbuf, long numBytes )
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{
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/* we need to ensure that previous writes are always seen before updating the index. */
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PaUtil_WriteMemoryBarrier();
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return rbuf->readIndex = (rbuf->readIndex + numBytes) & rbuf->bigMask;
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}
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/***************************************************************************
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** Return bytes written. */
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long PaUtil_WriteRingBuffer( PaUtilRingBuffer *rbuf, const void *data, long numBytes )
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{
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long size1, size2, numWritten;
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void *data1, *data2;
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numWritten = PaUtil_GetRingBufferWriteRegions( rbuf, numBytes, &data1, &size1, &data2, &size2 );
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if( size2 > 0 )
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{
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memcpy( data1, data, size1 );
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data = ((char *)data) + size1;
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memcpy( data2, data, size2 );
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}
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else
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{
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memcpy( data1, data, size1 );
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}
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PaUtil_AdvanceRingBufferWriteIndex( rbuf, numWritten );
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return numWritten;
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}
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/***************************************************************************
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** Return bytes read. */
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long PaUtil_ReadRingBuffer( PaUtilRingBuffer *rbuf, void *data, long numBytes )
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{
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long size1, size2, numRead;
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void *data1, *data2;
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numRead = PaUtil_GetRingBufferReadRegions( rbuf, numBytes, &data1, &size1, &data2, &size2 );
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if( size2 > 0 )
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{
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memcpy( data, data1, size1 );
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data = ((char *)data) + size1;
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memcpy( data, data2, size2 );
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}
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else
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{
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memcpy( data, data1, size1 );
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}
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PaUtil_AdvanceRingBufferReadIndex( rbuf, numRead );
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return numRead;
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}
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