source: roaraudio/plugins/alsavs/thread.c @ 4708:c9d40761088a

//thread.c:

/*
 *      Copyright (C) Philipp 'ph3-der-loewe' Schafft - 2010-2011
 *      Copyright (C) Hans-Kristian 'maister' Arntzen - 2010
 *
 *  This file is part of libroar a part of RoarAudio,
 *  a cross-platform sound system for both, home and professional use.
 *  See README for details.
 *
 *  This file is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 3
 *  as published by the Free Software Foundation.
 *
 *  libroar 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 software; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 *  NOTE for everyone want's to change something and send patches:
 *  read README and HACKING! There a addition information on
 *  the license of this document you need to read before you send
 *  any patches.
 *
 *  NOTE for uses of non-GPL (LGPL,...) software using libesd, libartsc
 *  or libpulse*:
 *  The libs libroaresd, libroararts and libroarpulse link this lib
 *  and are therefore GPL. Because of this it may be illigal to use
 *  them with any software that uses libesd, libartsc or libpulse*.
 */


#include "roar.h"
#define CHUNK_SIZE 256


// Writes to the FIFO buffer. Waits until there is room to write.
size_t roar_write(struct roar_alsa_pcm *self, const char *buf, size_t size) {
 /* Wait until we have a ready buffer */
 while (1) {
  /* Should the thread be shut down while we're running, return with error */
  if ( !self->thread_active )
   return 0;

  //fprintf(stderr, "%d + %d : %d\n", (int)self->bufptr, (int)size, (int)self->bufsize);
  pthread_mutex_lock(&(self->lock));
  if (self->bufptr + size <= self->bufsize) {
   pthread_mutex_unlock(&(self->lock));
   break;
  }
  pthread_mutex_unlock(&(self->lock));

  pthread_cond_signal(&(self->cond));
  /* Sleeps until we can write to the FIFO. */
  pthread_mutex_lock(&(self->cond_lock));
  pthread_cond_wait(&(self->cond), &(self->cond_lock));
  pthread_mutex_unlock(&(self->cond_lock));
 }

 pthread_mutex_lock(&(self->lock));
 memcpy(self->buffer + self->bufptr, buf, size);
 self->bufptr += (int)size;
 pthread_mutex_unlock(&(self->lock));

 /* Send signal to thread that buffer has been updated */
 pthread_cond_signal(&(self->cond));

 return size;
}

#define _TEST_CANCEL() do { \
 if ( !self->thread_active ) \
  goto test_quit; \
} while(0)

// Attemps to drain the buffer at all times and write to libroar.
// If there is no data, it will wait for roar_write() to fill up more data.
void* roar_thread (void * thread_data) {
 /* We share data between thread and callable functions */
 struct roar_alsa_pcm *self = thread_data;
 int rc;

 /* Plays back data as long as there is data in the buffer. Else, sleep until it can. */
 /* Two loops! :3 Beware! */
 while(1) {
  while(1) {
   _TEST_CANCEL();
   // We ask the server to send its latest backend data. Do not really care about errors atm.
   // We only bother to check after 1 sec of audio has been played, as it might be quite inaccurate in the start of the stream.

   /* If the buffer is empty or we've stopped the stream. Jump out of this for loop */
   pthread_mutex_lock(&(self->lock));
   if ( self->bufptr < CHUNK_SIZE ) {
    pthread_mutex_unlock(&(self->lock));
    break;
   }
   pthread_mutex_unlock(&(self->lock));

   rc = roar_vio_write(&(self->stream_vio), self->buffer, CHUNK_SIZE);

   /* If this happens, we should make sure that subsequent and current calls to rsd_write() will fail. */
   if ( rc < 0 ) {
    _TEST_CANCEL();
    roar_reset(self);

    /* Wakes up a potentially sleeping fill_buffer() */
    pthread_cond_signal(&(self->cond));

    /* This thread will not be joined, so detach. */
    pthread_detach(pthread_self());
    pthread_exit(NULL);
   }

   if ( !self->has_written ) {
    pthread_mutex_lock(&(self->lock));
    clock_gettime(CLOCK_MONOTONIC, &(self->start_tv));
    self->has_written = 1;
    pthread_mutex_unlock(&(self->lock));
   }

   pthread_mutex_lock(&(self->lock));
   self->total_written += rc;
   pthread_mutex_unlock(&(self->lock));

   /* "Drains" the buffer. This operation looks kinda expensive with large buffers, but hey. D: */
   pthread_mutex_lock(&(self->lock));
   memmove(self->buffer, self->buffer + rc, self->bufsize - rc);
   self->bufptr -= rc;
   pthread_mutex_unlock(&(self->lock));

   /* Buffer has decreased, signal fill_buffer() */
   pthread_cond_signal(&(self->cond));

  }

  /* If we're still good to go, sleep. We are waiting for fill_buffer() to fill up some data. */
test_quit:
  if ( self->thread_active ) {
   pthread_cond_signal(&(self->cond));
   pthread_mutex_lock(&(self->cond_lock));
   pthread_cond_wait(&(self->cond), &(self->cond_lock));
   pthread_mutex_unlock(&(self->cond_lock));
  } else {
   /* Abandon the ship, chap. */
   pthread_cond_signal(&(self->cond));
   pthread_exit(NULL);
  }

 }
}

void roar_drain(struct roar_alsa_pcm *self) {
 struct timespec now_tv;
 int64_t temp, temp2;

 /* If the audio playback has started on the server we need to use timers. */
 if ( self->has_written ) {

  /* Falls back to gettimeofday() when CLOCK_MONOTONIC is not supported */

  /* Calculates the amount of bytes that the server has consumed. */
  clock_gettime(CLOCK_MONOTONIC, &now_tv);

  temp   = (int64_t)now_tv.tv_sec - (int64_t)self->start_tv.tv_sec;

  temp  *= self->info.rate * self->info.channels * self->info.bits / 8;

  temp2  = (int64_t)now_tv.tv_nsec - (int64_t)self->start_tv.tv_nsec;
  temp2 *= self->info.rate * self->info.channels * self->info.bits / 8;
  temp2 /= 1000000000LL;
  temp  += temp2;
  /* Calculates the amount of data we have in our virtual buffer. Only used to calculate delay. */
  self->bytes_in_buffer = (int)((int64_t)self->total_written + (int64_t)self->bufptr - temp);
 } else {
  self->bytes_in_buffer = self->bufptr;
 }
}

//ll