ringbuffer.h

/*
 * iaxclient: a cross-platform IAX softphone library
 *
 * Copyrights:
 * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
 * Copyright (C) 2007, Wimba, Inc.
 *
 * Contributors:
 * <see below>
 * Peter Grayson <jpgrayson@gmail.com>
 *
 * This program is free software, distributed under the terms of
 * the GNU Lesser (Library) General Public License.
 */

/*
 * Ring Buffer utility.
 *
 * Author: Phil Burk, http://www.softsynth.com
 * modified for SMP safety on OS X by Bjorn Roche.
 * also allowed for const where possible.
 * Note that this is safe only for a single-thread reader
 * and a single-thread writer.
 *
 * Originally distributed with 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.
 */

#ifndef RINGBUFFER_H
#define RINGBUFFER_H

#ifdef __cplusplus
extern "C"
{
#endif /* __cplusplus */

typedef struct rb_RingBuffer
{
    long   bufferSize; /* Number of bytes in FIFO. Power of 2. Set by rb_InitializeRingBuffer. */
    long   writeIndex; /* Index of next writable byte. Set by rb_AdvanceRingBufferWriteIndex. */
    long   readIndex;  /* Index of next readable byte. Set by rb_AdvanceRingBufferReadIndex. */
    long   bigMask;    /* Used for wrapping indices with extra bit to distinguish full/empty. */
    long   smallMask;  /* Used for fitting indices to buffer. */
    char  *buffer;
}rb_RingBuffer;

long rb_InitializeRingBuffer( rb_RingBuffer *rbuf, long numBytes, void *dataPtr );

void rb_FlushRingBuffer( rb_RingBuffer *rbuf );

long rb_GetRingBufferWriteAvailable( rb_RingBuffer *rbuf );

long rb_GetRingBufferReadAvailable( rb_RingBuffer *rbuf );

long rb_WriteRingBuffer( rb_RingBuffer *rbuf, const void *data, long numBytes );

long rb_ReadRingBuffer( rb_RingBuffer *rbuf, void *data, long numBytes );

long rb_GetRingBufferWriteRegions( rb_RingBuffer *rbuf, long numBytes,
                                       void **dataPtr1, long *sizePtr1,
                                       void **dataPtr2, long *sizePtr2 );

long rb_AdvanceRingBufferWriteIndex( rb_RingBuffer *rbuf, long numBytes );

long rb_GetRingBufferReadRegions( rb_RingBuffer *rbuf, long numBytes,
                                      void **dataPtr1, long *sizePtr1,
                                      void **dataPtr2, long *sizePtr2 );

long rb_AdvanceRingBufferReadIndex( rb_RingBuffer *rbuf, long numBytes );

#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* RINGBUFFER_H */

---