From c0507f561089d92d603e60c32aa6a8c87ea7e900 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Sat, 14 Apr 2001 02:30:30 +0000
Subject: [PATCH] update for the lastest alsa pcm mmap api. not as bad as at
 first appearance

---
 libs/audio/targets/snd_alsa_0_9.c | 79 ++++++++++---------------------
 1 file changed, 24 insertions(+), 55 deletions(-)

diff --git a/libs/audio/targets/snd_alsa_0_9.c b/libs/audio/targets/snd_alsa_0_9.c
index ee1686eee..4f36f22f4 100644
--- a/libs/audio/targets/snd_alsa_0_9.c
+++ b/libs/audio/targets/snd_alsa_0_9.c
@@ -43,7 +43,7 @@
 static int  snd_inited;
 
 static snd_pcm_t *pcm;
-static const snd_pcm_channel_area_t *mmap_areas;
+//static const snd_pcm_channel_area_t *mmap_areas;
 static char *pcmname = NULL;
 size_t      buffer_size;
 
@@ -187,7 +187,7 @@ SNDDMA_Init (void)
 		goto error;
 	}
 
-	mmap_areas = snd_pcm_mmap_running_areas (pcm);
+	//mmap_areas = snd_pcm_mmap_running_areas (pcm);
 
 	shm = &sn;
 	memset ((dma_t *) shm, 0, sizeof (*shm));
@@ -204,7 +204,8 @@ SNDDMA_Init (void)
 	buffer_size = snd_pcm_hw_params_get_buffer_size (hw);
 	shm->samples = buffer_size * shm->channels;	// mono samples in buffer
 	shm->speed = rate;
-	shm->buffer = (unsigned char *) mmap_areas->addr;
+	SNDDMA_GetDMAPos ();//XXX sets shm->buffer
+	//shm->buffer = (unsigned char *) mmap_areas->addr;
 	Con_Printf ("%5d stereo\n", shm->channels - 1);
 	Con_Printf ("%5d samples\n", shm->samples);
 	Con_Printf ("%5d samplepos\n", shm->samplepos);
@@ -221,34 +222,21 @@ SNDDMA_Init (void)
 	return 0;
 }
 
-static inline int
-get_hw_ptr ()
-{
-	size_t      app_ptr;
-	snd_pcm_sframes_t delay;
-	int         hw_ptr;
-
-	if (snd_pcm_state (pcm) != SND_PCM_STATE_RUNNING)
-		return 0;
-	app_ptr = snd_pcm_mmap_offset (pcm);
-	snd_pcm_delay (pcm, &delay);
-	hw_ptr = app_ptr - delay;
-	if (hw_ptr < 0)
-		hw_ptr += buffer_size;
-	return hw_ptr;
-}
-
 int
 SNDDMA_GetDMAPos (void)
 {
-	int         hw_ptr;
+	snd_pcm_uframes_t offset;
+	snd_pcm_uframes_t nframes = shm->samples/shm->channels;
+	const snd_pcm_channel_area_t *areas;
 
 	if (!snd_inited)
 		return 0;
 
-	hw_ptr = get_hw_ptr ();
-	hw_ptr *= shm->channels;
-	shm->samplepos = hw_ptr;
+	snd_pcm_mmap_begin (pcm, &areas, &offset, &nframes);
+	offset *= shm->channels;
+	nframes *= shm->channels;
+	shm->samplepos = offset;
+	shm->buffer = areas->addr;//XXX FIXME there's an area per channel
 	return shm->samplepos;
 }
 
@@ -262,51 +250,32 @@ SNDDMA_Shutdown (void)
 }
 
 /*
-==============
-SNDDMA_Submit
+	SNDDMA_Submit
 
-Send sound to device if buffer isn't really the dma buffer
-===============
+	Send sound to device if buffer isn't really the dma buffer
 */
 void
 SNDDMA_Submit (void)
 {
-	int         count = paintedtime - soundtime;
-	int         avail;
-	int         missed;
+	snd_pcm_uframes_t offset;
+	snd_pcm_uframes_t nframes;
+	const snd_pcm_channel_area_t *areas;
 	int         state;
-	int         hw_ptr;
-	int         offset;
+	int         count = paintedtime - soundtime;
+
+	nframes = count / shm->channels;
+
+	snd_pcm_mmap_begin (pcm, &areas, &offset, &nframes);
 
 	state = snd_pcm_state (pcm);
 
 	switch (state) {
 		case SND_PCM_STATE_PREPARED:
-			snd_pcm_mmap_forward (pcm, count);
+			snd_pcm_mmap_commit (pcm, offset, nframes);
 			snd_pcm_start (pcm);
 			break;
 		case SND_PCM_STATE_RUNNING:
-			hw_ptr = get_hw_ptr ();
-			missed = hw_ptr - shm->samplepos / shm->channels;
-			if (missed < 0)
-				missed += buffer_size;
-			count -= missed;
-			offset = snd_pcm_mmap_offset (pcm);
-			if (offset > hw_ptr)
-				count -= (offset - hw_ptr);
-			else
-				count -= (buffer_size - hw_ptr + offset);
-			if (count < 0) {
-				snd_pcm_rewind (pcm, -count);
-			} else {
-				avail = snd_pcm_avail_update (pcm);
-				if (avail < 0)
-					avail = buffer_size;
-				if (count > avail)
-					count = avail;
-				if (count)
-					snd_pcm_mmap_forward (pcm, count);
-			}
+			snd_pcm_mmap_commit (pcm, offset, nframes);
 			break;
 		default:
 			break;