From f49ae1ab7a35e7d1c855d66a60d68b9dd9b57682 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Thu, 27 Dec 2012 18:32:59 +1100
Subject: [PATCH] sound: allow a digit in file name to attenutate volume.

Signed-off-by: NeilBrown <neil@brown.name>
---
 sound/sound.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 56 insertions(+), 6 deletions(-)

diff --git a/sound/sound.c b/sound/sound.c
index f2f0b4d..b83dbe2 100644
--- a/sound/sound.c
+++ b/sound/sound.c
@@ -136,6 +136,7 @@ struct sound {
 	int period_bytes;
 	int bytes, bytes_used, last_read;
 	int eof;
+	int attenuate; /* shift left */
 
 	/* An audio file can contain multiple chunks.
 	 * Here we record the remaining bytes expected
@@ -158,6 +159,7 @@ struct dev {
 	int		buf_size;
 	int		period_bytes;
 	int		sample_bytes;
+	int		attenuate; /* shift left */
 	int		present;
 	int		pcm_format, channels, rate;
 };
@@ -476,6 +478,7 @@ void set_params(struct dev *dev, struct sound *sound)
 	dev->pcm_format = sound->pcm_format;
 	dev->channels = sound->channels;
 	dev->rate = sound->rate;
+	dev->attenuate = sound->attenuate;
 	dev->sample_bytes = sound->sample_bytes;
 	dev->period_bytes = sound->period_bytes;
 	if (dev->buf_size < dev->period_bytes) {
@@ -535,15 +538,33 @@ struct sound *open_sound(char *dir, char *name, int ino)
 	s->posn = 0;
 	s->bytes = s->bytes_used = 0;
 
+	/* Filename must contain the  'scenario' name which
+	 * determines mixer settings, and may contain a single
+	 * digit which reduces the volume, and a millisecond offset
+	 * which is digits preceeded by a hyphen.
+	 * Typically it starts with a numeric priority.
+	 * So:  05-ring-alert5-20
+	 * Would play the sound with the 'alert' scenario and 50% volume
+	 * starting 20ms from start.
+	 */
 	/* check for millisecond suffix */
 	eos = name + strlen(name);
-	while (eos > name && isdigit(eos[-1]))
-		eos--;
-	if (eos > name && eos[-1] == '-' && eos[0]) {
-		s->posn = atol(eos);
-		eos--;
+	eos1 = eos;
+	while (eos1 > name && isdigit(eos1[-1]))
+		eos1--;
+	if (eos1 > name && eos1[-1] == '-' && eos1[0]) {
+		s->posn = atol(eos1);
+		eos = eos1 - 1;
 	}
-	/* Now pick off scenario name */
+	/* Now pick off volume and scenario name */
+	if (eos > name && isdigit(eos[-1])) {
+		int n = eos[-1] - '0';
+		if (n == 0)
+			n = 10;
+		s->attenuate = 10 - n;
+		eos--;
+	} else
+		s->attenuate = 0;
 	eos1 = eos;
 	while (eos1 > name && isalpha(eos1[-1]))
 		eos1--;
@@ -673,9 +694,36 @@ void scan_dir(char *path, struct list_head *soundqueue)
 		}
 }
 
+static void scale_buf(struct dev *dev)
+{
+	int i;
+	switch (dev->pcm_format) {
+	case SND_PCM_FORMAT_U8:
+		for (i = 0; i < dev->period_bytes; i++) {
+			int v = dev->period_buf[i];
+			v = v >> dev->attenuate;
+			dev->period_buf[i] = v;
+		}
+		break;
+
+	case SND_PCM_FORMAT_S16_LE:
+		printf("period = %d\n", dev->period_bytes);
+		for (i = 0; i < dev->period_bytes / 2; i++) {
+			int v = *(short*)(dev->period_buf+i*2);
+			v = v >> dev->attenuate;
+			*(short*)(dev->period_buf+i*2) = v;
+		}
+		break;
+	default:
+		break;
+	}
+}
+
 void play_buf(struct dev *dev)
 {
 	if (dev->present == dev->period_bytes) {
+		if (dev->attenuate)
+			scale_buf(dev);
 		alarm(30);
 		snd_pcm_writei(dev->handle,
 			       dev->period_buf,
@@ -692,6 +740,8 @@ void dev_close(struct dev *dev)
 	if (dev->present) {
 		memset(dev->period_buf + dev->present, 0,
 		       dev->period_bytes - dev->present);
+		if (dev->attenuate)
+			scale_buf(dev);
 		snd_pcm_writei(dev->handle,
 			       dev->period_buf,
 			       dev->period_bytes / dev->sample_bytes);
-- 
2.39.5