From 4b820e4de0335ecb1f6c44f87c0e7a8ddb520f1f Mon Sep 17 00:00:00 2001
From: Alexandre Ratchov <alex@caoua.org>
Date: Mon, 17 Mar 2014 18:38:57 +0100
Subject: [PATCH] after every cycle, check if this was the last cycle in which
 case the device may be closed and shouldn't be used

---
 sndiod/dev.c     | 110 +++++++++++++++++++++--------------------------
 sndiod/dev.h     |   2 +-
 sndiod/siofile.c |   3 +-
 3 files changed, 53 insertions(+), 62 deletions(-)

diff --git a/sndiod/dev.c b/sndiod/dev.c
index b1db05a..53d9425 100644
--- a/sndiod/dev.c
+++ b/sndiod/dev.c
@@ -55,11 +55,10 @@ void dev_mix_adjvol(struct dev *);
 int rec_filt_resamp(struct slot *, void *, void *, int);
 int rec_filt_enc(struct slot *, void *, void *, int);
 void dev_sub_bcopy(struct dev *, struct slot *);
-void dev_full_cycle(struct dev *);
 
 void dev_onmove(struct dev *, int);
 void dev_master(struct dev *, unsigned int);
-void dev_cycle(struct dev *);
+int dev_cycle(struct dev *);
 int dev_getpos(struct dev *);
 struct dev *dev_new(char *, struct aparams *, unsigned int, unsigned int,
     unsigned int, unsigned int, unsigned int, unsigned int);
@@ -74,7 +73,6 @@ struct dev *dev_bynum(int);
 void dev_del(struct dev *);
 unsigned int dev_roundof(struct dev *, unsigned int);
 void dev_wakeup(struct dev *);
-void dev_clear(struct dev *);
 void dev_sync_attach(struct dev *);
 void dev_mmcstart(struct dev *);
 void dev_mmcstop(struct dev *);
@@ -635,16 +633,6 @@ dev_mix_badd(struct dev *d, struct slot *s)
 void
 dev_empty_cycle(struct dev *d)
 {
-	unsigned char *base;
-	int nsamp;
-
-	base = (unsigned char *)DEV_PBUF(d);
-	nsamp = d->round * d->pchan;
-	memset(base, 0, nsamp * sizeof(adata_t));
-	if (d->encbuf) {
-		enc_do(&d->enc, (unsigned char *)DEV_PBUF(d),
-		    d->encbuf, d->round);
-	}
 }
 
 /*
@@ -760,18 +748,58 @@ dev_sub_bcopy(struct dev *d, struct slot *s)
 	abuf_wcommit(&s->sub.buf, ocount * s->sub.bpf);
 }
 
-void
-dev_full_cycle(struct dev *d)
+/*
+ * run a one block cycle, return 0 if the device was stopped and/or
+ * closed.
+ */
+int
+dev_cycle(struct dev *d)
 {
 	struct slot *s, **ps;
 	unsigned char *base;
 	int nsamp;
 
+	/*
+	 * check if the device is actually used. If it isn't,
+	 * then close it
+	 */
+	if (d->slot_list == NULL && d->tstate != MMC_RUN) {
+		if (log_level >= 2) {
+			dev_log(d);
+			log_puts(": device stopped\n");
+		}
+		dev_sio_stop(d);
+		d->pstate = DEV_INIT;
+		if (d->refcnt == 0)
+			dev_close(d);
+		return 0;
+	}
+
+	if (d->prime > 0) {
+#ifdef DEBUG
+		if (log_level >= 4) {
+			dev_log(d);
+			log_puts(": empty cycle, prime = ");
+			log_putu(d->prime);
+			log_puts("\n");
+		}
+#endif
+		base = (unsigned char *)DEV_PBUF(d);
+		nsamp = d->round * d->pchan;
+		memset(base, 0, nsamp * sizeof(adata_t));
+		if (d->encbuf) {
+			enc_do(&d->enc, (unsigned char *)DEV_PBUF(d),
+			    d->encbuf, d->round);
+		}
+		d->prime -= d->round;
+		return 1;
+	}
+
 	d->delta -= d->round;
 #ifdef DEBUG
 	if (log_level >= 4) {
 		dev_log(d);
-		log_puts(": dev_full_cycle: clk=");
+		log_puts(": full cycle: delta = ");
 		log_puti(d->delta);
 		if (d->mode & MODE_PLAY) {
 			log_puts(", poffs = ");
@@ -897,6 +925,7 @@ dev_full_cycle(struct dev *d)
 		enc_do(&d->enc, (unsigned char *)DEV_PBUF(d),
 		    d->encbuf, d->round);
 	}
+	return 1;
 }
 
 /*
@@ -939,38 +968,6 @@ dev_master(struct dev *d, unsigned int master)
 		dev_mix_adjvol(d);
 }
 
-void
-dev_cycle(struct dev *d)
-{
-	if (d->slot_list == NULL && d->tstate != MMC_RUN) {
-		if (log_level >= 2) {
-			dev_log(d);
-			log_puts(": device stopped\n");
-		}
-		dev_sio_stop(d);
-		d->pstate = DEV_INIT;
-		if (d->refcnt == 0)
-			dev_close(d);
-		else
-			dev_clear(d);
-		return;
-	}
-#ifdef DEBUG
-	if (log_level >= 4) {
-		dev_log(d);
-		log_puts(": device cycle, prime = ");
-		log_putu(d->prime);
-		log_puts("\n");
-	}
-#endif
-	if (d->prime > 0) {
-		d->prime -= d->round;
-		dev_empty_cycle(d);
-	} else {
-		dev_full_cycle(d);
-	}
-}
-
 /*
  * return the latency that a stream would have if it's attached
  */
@@ -1173,7 +1170,6 @@ dev_close(struct dev *d)
 			xfree(d->decbuf);
 		xfree(d->rbuf);
 	}
-	dev_clear(d);
 }
 
 int
@@ -1303,8 +1299,12 @@ dev_wakeup(struct dev *d)
 		} else {
 			d->prime = 0;
 		}
+		d->poffs = 0;
 
-		/* empty cycles don't increment delta */
+		/* 
+		 * empty cycles don't increment delta, so it's ok to
+		 * start at 0
+		 **/
 		d->delta = 0; 
 
 		d->pstate = DEV_RUN;
@@ -1312,16 +1312,6 @@ dev_wakeup(struct dev *d)
 	}
 }
 
-/*
- * Clear buffers of the play and record chains so that when the device
- * is started, playback and record start in sync.
- */
-void
-dev_clear(struct dev *d)
-{
-	d->poffs = 0;
-}
-
 /*
  * check that all clients controlled by MMC are ready to start, if so,
  * attach them all at the same position
diff --git a/sndiod/dev.h b/sndiod/dev.h
index 01af7f2..f3d482c 100644
--- a/sndiod/dev.h
+++ b/sndiod/dev.h
@@ -206,7 +206,7 @@ unsigned int dev_roundof(struct dev *, unsigned int);
  * interface to hardware device
  */
 void dev_onmove(struct dev *, int);
-void dev_cycle(struct dev *);
+int dev_cycle(struct dev *);
 
 /*
  * midi & midi call-backs
diff --git a/sndiod/siofile.c b/sndiod/siofile.c
index 2fd0628..39801f4 100644
--- a/sndiod/siofile.c
+++ b/sndiod/siofile.c
@@ -348,7 +348,8 @@ dev_sio_run(void *arg)
 				panic();
 			}
 #endif
-			dev_cycle(d);
+			if (!dev_cycle(d))
+				return;
 			if (d->mode & MODE_PLAY) {
 				d->sio.cstate = DEV_SIO_WRITE;
 				d->sio.todo = d->round * d->pchan * d->par.bps;