non/Timeline/Disk_Stream.C

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/*******************************************************************************/
/* Copyright (C) 2008 Jonathan Moore Liles */
/* */
/* This program is free software; you can redistribute it and/or modify it */
/* under the terms of the GNU General Public License as published by the */
/* Free Software Foundation; either version 2 of the License, or (at your */
/* option) any later version. */
/* */
/* This program is distributed in the hope that it will be useful, but WITHOUT */
/* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or */
/* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for */
/* more details. */
/* */
/* You should have received a copy of the GNU General Public License along */
/* with This program; see the file COPYING. If not,write to the Free Software */
/* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/*******************************************************************************/
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#include "Disk_Stream.H"
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#include "Track.H"
#include "Audio_Sequence.H"
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#include "Port.H"
#include "Engine.H" // for locking.
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#include "dsp.h"
/**********/
/* Engine */
/**********/
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/* A Disk_Stream uses a separate I/O thread to stream a track's
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regions from disk into a ringbuffer to be processed by the RT
thread (or vice-versa). The I/O thread syncronizes access with the
user thread via the Timeline mutex. The size of the buffer (in
seconds) must be set before any Disk_Stream objects are created;
that is, at startup time. The default is 5 seconds, which may or
may not be excessive depending on various external factors. */
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/* FIXME: deal with (jack) buffer size changes */
/* FIXME: needs error handling everywhere! */
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/* TODO: read/write data from/to disk in larger chunks to avoid
* excessive seeking. 256k is supposedly the sweetspot. */
//float Disk_Stream::seconds_to_buffer = 5.0f;
float Disk_Stream::seconds_to_buffer = 2.0f;
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/* this is really only a rough estimate. The actual amount of data
read depends on many factors. Overlapping regions, for example, will
require more data to be read from disk, as will varying channel
counts.*/
size_t Disk_Stream::disk_io_kbytes = 256;
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Disk_Stream::Disk_Stream ( Track *th, float frame_rate, nframes_t nframes, int channels ) : _th( th )
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{
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assert( channels );
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_frame = 0;
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_thread = 0;
_terminate = false;
_pending_seek = -1;
_xruns = 0;
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_total_blocks = frame_rate * seconds_to_buffer / nframes;
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_nframes = nframes;
size_t bufsize = _total_blocks * nframes * sizeof( sample_t );
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if ( disk_io_kbytes )
_disk_io_blocks = ( bufsize * channels ) / ( disk_io_kbytes * 1024 );
else
_disk_io_blocks = 1;
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for ( int i = channels; i--; )
_rb.push_back( jack_ringbuffer_create( bufsize ) );
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sem_init( &_blocks, 0, _total_blocks );
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}
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Disk_Stream::~Disk_Stream ( )
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{
/* it isn't safe to do all this with the RT thread running */
engine->lock();
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_th = NULL;
sem_destroy( &_blocks );
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for ( int i = channels(); i--; )
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jack_ringbuffer_free( _rb[ i ] );
engine->unlock();
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}
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/* THREAD: RT */
/** flush buffers and reset. Must only be called from the RT thread. */
void
Disk_Stream::flush ( bool is_output )
{
/* flush buffers */
for ( int i = channels(); i--; )
jack_ringbuffer_read_advance( _rb[ i ], jack_ringbuffer_read_space( _rb[ i ] ) );
/* sem_destroy( &_blocks ); */
/* if ( is_output ) */
/* sem_init( &_blocks, 0, _total_blocks ); */
/* else */
/* sem_init( &_blocks, 0, 0 ); */
if ( is_output )
{
int n;
sem_getvalue( &_blocks, &n );
n = _total_blocks - n;
while ( n-- )
sem_post( &_blocks );
}
else
{
sem_destroy( &_blocks );
sem_init( &_blocks, 0, 0 );
}
}
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/** stop the IO thread, block until it finishes. */
void
Disk_Stream::shutdown ( void )
{
_terminate = true;
/* try to wake the thread so it'll see that it's time to die */
block_processed();
if ( _thread )
pthread_join( _thread, NULL );
_terminate = false;
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}
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Audio_Sequence *
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Disk_Stream::track ( void )
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{
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return (Audio_Sequence*)_th->track();
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}
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/** start Disk_Stream thread */
void
Disk_Stream::run ( void )
{
if ( pthread_create( &_thread, NULL, &Disk_Stream::disk_thread, this ) != 0 )
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/* error */;
}
/* to be called when the JACK buffer size changes. */
void
Disk_Stream::resize ( nframes_t nframes )
{
if ( nframes != _nframes )
/* FIXME: to something here! */;
}
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/* static wrapper */
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void *
Disk_Stream::disk_thread ( void *arg )
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{
((Disk_Stream*)arg)->disk_thread();
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return NULL;
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}
int
Disk_Stream::buffer_percent ( void )
{
int n;
sem_getvalue( &_blocks, &n );
return 100 - (n * 100 / _total_blocks);
}