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| -rw-r--r-- | pd/portaudio/pablio/ringbuffer.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/pd/portaudio/pablio/ringbuffer.c b/pd/portaudio/pablio/ringbuffer.c new file mode 100644 index 00000000..f1fc819e --- /dev/null +++ b/pd/portaudio/pablio/ringbuffer.c @@ -0,0 +1,199 @@ +/* + * $Id: ringbuffer.c,v 1.3 2006-08-07 23:08:10 millerpuckette Exp $ + * ringbuffer.c + * Ring Buffer utility.. + * + * Author: Phil Burk, http://www.softsynth.com + * + * This program uses the PortAudio Portable Audio Library. + * For more information see: http://www.audiomulch.com/portaudio/ + * 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. + * + * 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. + * + * 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. + * + */ +#include <stdio.h> +#include <stdlib.h> +#include <math.h> +#include "ringbuffer.h" +#include <string.h> + +/*************************************************************************** + * Initialize FIFO. + * numBytes must be power of 2, returns -1 if not. + */ +long RingBuffer_Init( RingBuffer *rbuf, long numBytes, void *dataPtr ) +{ + if( ((numBytes-1) & numBytes) != 0) return -1; /* Not Power of two. */ + rbuf->bufferSize = numBytes; + rbuf->buffer = (char *)dataPtr; + RingBuffer_Flush( rbuf ); + rbuf->bigMask = (numBytes*2)-1; + rbuf->smallMask = (numBytes)-1; + return 0; +} +/*************************************************************************** +** Return number of bytes available for reading. */ +long RingBuffer_GetReadAvailable( RingBuffer *rbuf ) +{ + return ( (rbuf->writeIndex - rbuf->readIndex) & rbuf->bigMask ); +} +/*************************************************************************** +** Return number of bytes available for writing. */ +long RingBuffer_GetWriteAvailable( RingBuffer *rbuf ) +{ + return ( rbuf->bufferSize - RingBuffer_GetReadAvailable(rbuf)); +} + +/*************************************************************************** +** Clear buffer. Should only be called when buffer is NOT being read. */ +void RingBuffer_Flush( RingBuffer *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 RingBuffer_GetWriteRegions( RingBuffer *rbuf, long numBytes, + void **dataPtr1, long *sizePtr1, + void **dataPtr2, long *sizePtr2 ) +{ + long index; + long available = RingBuffer_GetWriteAvailable( 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 RingBuffer_AdvanceWriteIndex( RingBuffer *rbuf, long numBytes ) +{ + 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 RingBuffer_GetReadRegions( RingBuffer *rbuf, long numBytes, + void **dataPtr1, long *sizePtr1, + void **dataPtr2, long *sizePtr2 ) +{ + long index; + long available = RingBuffer_GetReadAvailable( 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 RingBuffer_AdvanceReadIndex( RingBuffer *rbuf, long numBytes ) +{ + return rbuf->readIndex = (rbuf->readIndex + numBytes) & rbuf->bigMask; +} + +/*************************************************************************** +** Return bytes written. */ +long RingBuffer_Write( RingBuffer *rbuf, void *data, long numBytes ) +{ + long size1, size2, numWritten; + void *data1, *data2; + numWritten = RingBuffer_GetWriteRegions( 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 ); + } + RingBuffer_AdvanceWriteIndex( rbuf, numWritten ); + return numWritten; +} + +/*************************************************************************** +** Return bytes read. */ +long RingBuffer_Read( RingBuffer *rbuf, void *data, long numBytes ) +{ + long size1, size2, numRead; + void *data1, *data2; + numRead = RingBuffer_GetReadRegions( 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 ); + } + RingBuffer_AdvanceReadIndex( rbuf, numRead ); + return numRead; +} |