freeswitch/src/mod/endpoints/mod_portaudio/pa_ringbuffer.h

#ifndef PA_RINGBUFFER_H
#define PA_RINGBUFFER_H
/*
 * $Id: pa_ringbuffer.h 1151 2006-11-29 02:11:16Z leland_lucius $
 * Portable Audio I/O Library
 * 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.
 *
 * This program is 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.
 */

/** @file
 @ingroup common_src
*/

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

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

/** Initialize Ring Buffer.

 @param rbuf The ring buffer.

 @param numBytes The number of bytes in the buffer and must be power of 2.

 @param dataPtr A pointer to a previously allocated area where the data
 will be maintained.  It must be numBytes long.

 @return -1 if numBytes is not a power of 2, otherwise 0.
*/
long PaUtil_InitializeRingBuffer( PaUtilRingBuffer *rbuf, long numBytes, void *dataPtr );

/** Clear buffer. Should only be called when buffer is NOT being read.

 @param rbuf The ring buffer.
*/
void PaUtil_FlushRingBuffer( PaUtilRingBuffer *rbuf );

/** Retrieve the number of bytes available in the ring buffer for writing.

 @param rbuf The ring buffer.

 @return The number of bytes available for writing.
*/
long PaUtil_GetRingBufferWriteAvailable( PaUtilRingBuffer *rbuf );

/** Retrieve the number of bytes available in the ring buffer for reading.

 @param rbuf The ring buffer.

 @return The number of bytes available for reading.
*/
long PaUtil_GetRingBufferReadAvailable( PaUtilRingBuffer *rbuf );

/** Write data to the ring buffer.

 @param rbuf The ring buffer.

 @param data The address of new data to write to the buffer.

 @param numBytes The number of bytes to be written.

 @return The number of bytes written.
*/
long PaUtil_WriteRingBuffer( PaUtilRingBuffer *rbuf, const void *data, long numBytes );

/** Read data from the ring buffer.

 @param rbuf The ring buffer.

 @param data The address where the data should be stored.

 @param numBytes The number of bytes to be read.

 @return The number of bytes read.
*/
long PaUtil_ReadRingBuffer( PaUtilRingBuffer *rbuf, void *data, long numBytes );

/** Get address of region(s) to which we can write data.

 @param rbuf The ring buffer.

 @param numBytes The number of bytes desired.

 @param dataPtr1 The address where the first (or only) region pointer will be
 stored.

 @param sizePtr1 The address where the first (or only) region length will be
 stored.

 @param dataPtr2 The address where the second region pointer will be stored if
 the first region is too small to satisfy numBytes.

 @param sizePtr2 The address where the second region length will be stored if
 the first region is too small to satisfy numBytes.

 @return The room available to be written or numBytes, whichever is smaller.
*/
long PaUtil_GetRingBufferWriteRegions( PaUtilRingBuffer *rbuf, long numBytes,
                                       void **dataPtr1, long *sizePtr1,
                                       void **dataPtr2, long *sizePtr2 );

/** Advance the write index to the next location to be written.

 @param rbuf The ring buffer.

 @param numBytes The number of bytes to advance.

 @return The new position.
*/
long PaUtil_AdvanceRingBufferWriteIndex( PaUtilRingBuffer *rbuf, long numBytes );

/** Get address of region(s) from which we can write data.

 @param rbuf The ring buffer.

 @param numBytes The number of bytes desired.

 @param dataPtr1 The address where the first (or only) region pointer will be
 stored.

 @param sizePtr1 The address where the first (or only) region length will be
 stored.

 @param dataPtr2 The address where the second region pointer will be stored if
 the first region is too small to satisfy numBytes.

 @param sizePtr2 The address where the second region length will be stored if
 the first region is too small to satisfy numBytes.

 @return The number of bytes available for reading.
*/
long PaUtil_GetRingBufferReadRegions( PaUtilRingBuffer *rbuf, long numBytes,
                                      void **dataPtr1, long *sizePtr1,
                                      void **dataPtr2, long *sizePtr2 );

/** Advance the read index to the next location to be read.

 @param rbuf The ring buffer.

 @param numBytes The number of bytes to advance.

 @return The new position.
*/
long PaUtil_AdvanceRingBufferReadIndex( PaUtilRingBuffer *rbuf, long numBytes );

#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* PA_RINGBUFFER_H */