103 lines
4.2 KiB
C
103 lines
4.2 KiB
C
#ifndef _RINGBUFFER_H
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#define _RINGBUFFER_H
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#ifdef __cplusplus
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extern "C"
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{
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#endif /* __cplusplus */
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/*
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* $Id: ringbuffer.h,v 1.1.1.1.4.2 2003/04/28 17:45:34 philburk Exp $
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* ringbuffer.h
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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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*
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* This program is distributed with the PortAudio Portable Audio Library.
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* For more information see: http://www.audiomulch.com/portaudio/
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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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* 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.
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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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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include "ringbuffer.h"
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#include <string.h>
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typedef struct
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{
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long bufferSize; /* Number of bytes in FIFO. Power of 2. Set by RingBuffer_Init. */
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/* These are declared volatile because they are written by a different thread than the reader. */
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volatile long writeIndex; /* Index of next writable byte. Set by RingBuffer_AdvanceWriteIndex. */
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volatile long readIndex; /* Index of next readable byte. Set by RingBuffer_AdvanceReadIndex. */
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long bigMask; /* Used for wrapping indices with extra bit to distinguish full/empty. */
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long smallMask; /* Used for fitting indices to buffer. */
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char *buffer;
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}
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RingBuffer;
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/*
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* Initialize Ring Buffer.
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* numBytes must be power of 2, returns -1 if not.
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*/
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long RingBuffer_Init( RingBuffer *rbuf, long numBytes, void *dataPtr );
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/* Clear buffer. Should only be called when buffer is NOT being read. */
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void RingBuffer_Flush( RingBuffer *rbuf );
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/* Return number of bytes available for writing. */
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long RingBuffer_GetWriteAvailable( RingBuffer *rbuf );
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/* Return number of bytes available for read. */
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long RingBuffer_GetReadAvailable( RingBuffer *rbuf );
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/* Return bytes written. */
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long RingBuffer_Write( RingBuffer *rbuf, void *data, long numBytes );
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/* Return bytes read. */
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long RingBuffer_Read( RingBuffer *rbuf, void *data, long numBytes );
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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 RingBuffer_GetWriteRegions( RingBuffer *rbuf, long numBytes,
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void **dataPtr1, long *sizePtr1,
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void **dataPtr2, long *sizePtr2 );
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long RingBuffer_AdvanceWriteIndex( RingBuffer *rbuf, long numBytes );
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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 read or numBytes, whichever is smaller.
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*/
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long RingBuffer_GetReadRegions( RingBuffer *rbuf, long numBytes,
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void **dataPtr1, long *sizePtr1,
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void **dataPtr2, long *sizePtr2 );
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long RingBuffer_AdvanceReadIndex( RingBuffer *rbuf, long numBytes );
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#ifdef __cplusplus
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}
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#endif /* __cplusplus */
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#endif /* _RINGBUFFER_H */
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