SV platform dependency builds

/*

 * $Id$

 * Portable Audio I/O Library

 * Ring Buffer utility.

 *

 * Author: Phil Burk, http://www.softsynth.com

 * modified for SMP safety on Mac OS X by Bjorn Roche

 * modified for SMP safety on Linux by Leland Lucius

 * also, allowed for const where possible

 * modified for multiple-byte-sized data elements by Sven Fischer 

 *

 * Note that this is safe only for a single-thread reader and a

 * single-thread writer.

 *

 * This program uses 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

*/

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

#include "pa_ringbuffer.h"

#include <string.h>

#include "pa_memorybarrier.h"

/***************************************************************************

 * Initialize FIFO.

 * elementCount must be power of 2, returns -1 if not.

 */

ring_buffer_size_t PaUtil_InitializeRingBuffer( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementSizeBytes, ring_buffer_size_t elementCount, void *dataPtr )

{

    if( ((elementCount-1) & elementCount) != 0) return -1; /* Not Power of two. */

    rbuf->bufferSize = elementCount;

    rbuf->buffer = (char *)dataPtr;

    PaUtil_FlushRingBuffer( rbuf );

    rbuf->bigMask = (elementCount*2)-1;

    rbuf->smallMask = (elementCount)-1;

    rbuf->elementSizeBytes = elementSizeBytes;

    return 0;

}

/***************************************************************************

** Return number of elements available for reading. */

ring_buffer_size_t PaUtil_GetRingBufferReadAvailable( const PaUtilRingBuffer *rbuf )

{

    return ( (rbuf->writeIndex - rbuf->readIndex) & rbuf->bigMask );

}

/***************************************************************************

** Return number of elements available for writing. */

ring_buffer_size_t PaUtil_GetRingBufferWriteAvailable( const PaUtilRingBuffer *rbuf )

{

    return ( rbuf->bufferSize - PaUtil_GetRingBufferReadAvailable(rbuf));

}

/***************************************************************************

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

void PaUtil_FlushRingBuffer( PaUtilRingBuffer *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 elementCount, whichever is smaller.

*/

ring_buffer_size_t PaUtil_GetRingBufferWriteRegions( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount,

                                       void **dataPtr1, ring_buffer_size_t *sizePtr1,

                                       void **dataPtr2, ring_buffer_size_t *sizePtr2 )

{

    ring_buffer_size_t   index;

    ring_buffer_size_t   available = PaUtil_GetRingBufferWriteAvailable( rbuf );

    if( elementCount > available ) elementCount = available;

    /* Check to see if write is not contiguous. */

    index = rbuf->writeIndex & rbuf->smallMask;

    if( (index + elementCount) > rbuf->bufferSize )

    {

        /* Write data in two blocks that wrap the buffer. */

        ring_buffer_size_t   firstHalf = rbuf->bufferSize - index;

        *dataPtr1 = &rbuf->buffer[index*rbuf->elementSizeBytes];

        *sizePtr1 = firstHalf;

        *dataPtr2 = &rbuf->buffer[0];

        *sizePtr2 = elementCount - firstHalf;

    }

    else

    {

        *dataPtr1 = &rbuf->buffer[index*rbuf->elementSizeBytes];

        *sizePtr1 = elementCount;

        *dataPtr2 = NULL;

        *sizePtr2 = 0;

    }

    if( available )

        PaUtil_FullMemoryBarrier(); /* (write-after-read) => full barrier */

    return elementCount;

}

/***************************************************************************

*/

ring_buffer_size_t PaUtil_AdvanceRingBufferWriteIndex( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount )

{

    /* ensure that previous writes are seen before we update the write index 

       (write after write)

    */

    PaUtil_WriteMemoryBarrier();

    return rbuf->writeIndex = (rbuf->writeIndex + elementCount) & 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 read or elementCount, whichever is smaller.

*/

ring_buffer_size_t PaUtil_GetRingBufferReadRegions( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount,

                                void **dataPtr1, ring_buffer_size_t *sizePtr1,

                                void **dataPtr2, ring_buffer_size_t *sizePtr2 )

{

    ring_buffer_size_t   index;

    ring_buffer_size_t   available = PaUtil_GetRingBufferReadAvailable( rbuf ); /* doesn't use memory barrier */

    if( elementCount > available ) elementCount = available;

    /* Check to see if read is not contiguous. */

    index = rbuf->readIndex & rbuf->smallMask;

    if( (index + elementCount) > rbuf->bufferSize )

    {

        /* Write data in two blocks that wrap the buffer. */

        ring_buffer_size_t firstHalf = rbuf->bufferSize - index;

        *dataPtr1 = &rbuf->buffer[index*rbuf->elementSizeBytes];

        *sizePtr1 = firstHalf;

        *dataPtr2 = &rbuf->buffer[0];

        *sizePtr2 = elementCount - firstHalf;

    }

    else

    {

        *dataPtr1 = &rbuf->buffer[index*rbuf->elementSizeBytes];

        *sizePtr1 = elementCount;

        *dataPtr2 = NULL;

        *sizePtr2 = 0;

    }

    if( available )

        PaUtil_ReadMemoryBarrier(); /* (read-after-read) => read barrier */

    return elementCount;

}

/***************************************************************************

*/

ring_buffer_size_t PaUtil_AdvanceRingBufferReadIndex( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount )

{

    /* ensure that previous reads (copies out of the ring buffer) are always completed before updating (writing) the read index. 

       (write-after-read) => full barrier

    */

    PaUtil_FullMemoryBarrier();

    return rbuf->readIndex = (rbuf->readIndex + elementCount) & rbuf->bigMask;

}

/***************************************************************************

** Return elements written. */

ring_buffer_size_t PaUtil_WriteRingBuffer( PaUtilRingBuffer *rbuf, const void *data, ring_buffer_size_t elementCount )

{

    ring_buffer_size_t size1, size2, numWritten;

    void *data1, *data2;

    numWritten = PaUtil_GetRingBufferWriteRegions( rbuf, elementCount, &data1, &size1, &data2, &size2 );

    if( size2 > 0 )

    {

        memcpy( data1, data, size1*rbuf->elementSizeBytes );

        data = ((char *)data) + size1*rbuf->elementSizeBytes;

        memcpy( data2, data, size2*rbuf->elementSizeBytes );

    }

    else

    {

        memcpy( data1, data, size1*rbuf->elementSizeBytes );

    }

    PaUtil_AdvanceRingBufferWriteIndex( rbuf, numWritten );

    return numWritten;

}

/***************************************************************************

** Return elements read. */

ring_buffer_size_t PaUtil_ReadRingBuffer( PaUtilRingBuffer *rbuf, void *data, ring_buffer_size_t elementCount )

{

    ring_buffer_size_t size1, size2, numRead;

    void *data1, *data2;

    numRead = PaUtil_GetRingBufferReadRegions( rbuf, elementCount, &data1, &size1, &data2, &size2 );

    if( size2 > 0 )

    {

        memcpy( data, data1, size1*rbuf->elementSizeBytes );

        data = ((char *)data) + size1*rbuf->elementSizeBytes;

        memcpy( data, data2, size2*rbuf->elementSizeBytes );

    }

    else

    {

        memcpy( data, data1, size1*rbuf->elementSizeBytes );

    }

    PaUtil_AdvanceRingBufferReadIndex( rbuf, numRead );

    return numRead;

}