#ifndef _RINGBUFFER_H#define _RINGBUFFER_H#ifdef __cplusplusextern "C"{#endif /* __cplusplus *//* * $Id: ringbuffer.h,v 1.3 2003/03/02 08:01:47 dmazzoni Exp $ * ringbuffer.h * Ring Buffer utility.. * * Author: Phil Burk, http://www.softsynth.com * * This program is distributed with 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>typedef struct{    long   bufferSize; /* Number of bytes in FIFO. Power of 2. Set by RingBuffer_Init. */    long   writeIndex; /* Index of next writable byte. Set by RingBuffer_AdvanceWriteIndex. */    long   readIndex;  /* Index of next readable byte. Set by RingBuffer_AdvanceReadIndex. */    long   bigMask;    /* Used for wrapping indices with extra bit to distinguish full/empty. */    long   smallMask;  /* Used for fitting indices to buffer. */    char *buffer;}RingBuffer;/* * Initialize Ring Buffer. * numBytes must be power of 2, returns -1 if not. */long RingBuffer_Init( RingBuffer *rbuf, long numBytes, void *dataPtr );/* Clear buffer. Should only be called when buffer is NOT being read. */void RingBuffer_Flush( RingBuffer *rbuf );/* Return number of bytes available for writing. */long RingBuffer_GetWriteAvailable( RingBuffer *rbuf );/* Return number of bytes available for read. */long RingBuffer_GetReadAvailable( RingBuffer *rbuf );/* Return bytes written. */long RingBuffer_Write( RingBuffer *rbuf, void *data, long numBytes );/* Return bytes read. */long RingBuffer_Read( RingBuffer *rbuf, void *data, long numBytes );/* 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 RingBuffer_AdvanceWriteIndex( RingBuffer *rbuf, long numBytes );/* 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 RingBuffer_AdvanceReadIndex( RingBuffer *rbuf, long numBytes );#ifdef __cplusplus}#endif /* __cplusplus */#endif /* _RINGBUFFER_H */