alsa/0024-pcm-plugin-tidy-snd_pcm_plugin_avail_update.patch

From fa1895aa2b4f3f154e537bee92860fe793045643 Mon Sep 17 00:00:00 2001
From: Jaroslav Kysela <perex@perex.cz>
Date: Sun, 3 Jan 2021 16:34:04 +0100
Subject: [PATCH 24/33] pcm: plugin - tidy snd_pcm_plugin_avail_update()

No functional changes - move the code to snd_pcm_plugin_sync_hw_ptr()
and put the mmap capture updates to separate function for readability.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
---
 src/pcm/pcm_plugin.c | 142 +++++++++++++++++++++++--------------------
 1 file changed, 76 insertions(+), 66 deletions(-)

diff --git a/src/pcm/pcm_plugin.c b/src/pcm/pcm_plugin.c
index ea60eb98986e..83793397a7f0 100644
--- a/src/pcm/pcm_plugin.c
+++ b/src/pcm/pcm_plugin.c
@@ -460,82 +460,92 @@ snd_pcm_plugin_mmap_commit(snd_pcm_t *pcm,
 	return xfer > 0 ? xfer : err;
 }
 
-static snd_pcm_sframes_t snd_pcm_plugin_avail_update(snd_pcm_t *pcm)
+static snd_pcm_sframes_t
+snd_pcm_plugin_sync_hw_ptr_capture(snd_pcm_t *pcm,
+				   snd_pcm_sframes_t slave_size)
 {
 	snd_pcm_plugin_t *plugin = pcm->private_data;
 	snd_pcm_t *slave = plugin->gen.slave;
-	snd_pcm_sframes_t slave_size;
+	const snd_pcm_channel_area_t *areas;
+	snd_pcm_uframes_t xfer, hw_offset, size;
 	int err;
 
-	slave_size = snd_pcm_avail_update(slave);
+	xfer = snd_pcm_mmap_capture_avail(pcm);
+	size = pcm->buffer_size - xfer;
+	areas = snd_pcm_mmap_areas(pcm);
+	hw_offset = snd_pcm_mmap_hw_offset(pcm);
+	while (size > 0 && slave_size > 0) {
+		snd_pcm_uframes_t frames = size;
+		snd_pcm_uframes_t cont = pcm->buffer_size - hw_offset;
+		const snd_pcm_channel_area_t *slave_areas;
+		snd_pcm_uframes_t slave_offset;
+		snd_pcm_uframes_t slave_frames = ULONG_MAX;
+		snd_pcm_sframes_t result;
+		/* As mentioned in the ALSA API (see pcm/pcm.c:942):
+		 * The function #snd_pcm_avail_update()
+		 * have to be called before any mmap begin+commit operation.
+		 * Otherwise the snd_pcm_areas_copy will not called a second time.
+		 * But this is needed, if the ring buffer wrap is reached and
+		 * there is more data available.
+		 */
+		slave_size = snd_pcm_avail_update(slave);
+		result = snd_pcm_mmap_begin(slave, &slave_areas, &slave_offset, &slave_frames);
+		if (result < 0) {
+			err = result;
+			goto error;
+		}
+		if (frames > cont)
+			frames = cont;
+		frames = (plugin->read)(pcm, areas, hw_offset, frames,
+					slave_areas, slave_offset, &slave_frames);
+		result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
+		if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
+			snd_pcm_sframes_t res;
+			res = plugin->undo_read(slave, areas, hw_offset, frames, slave_frames - result);
+			if (res < 0) {
+				err = res;
+				goto error;
+			}
+			frames -= res;
+		}
+		if (result <= 0) {
+			err = result;
+			goto error;
+		}
+		snd_pcm_mmap_hw_forward(pcm, frames);
+		if (frames == cont)
+			hw_offset = 0;
+		else
+			hw_offset += frames;
+		size -= frames;
+		slave_size -= slave_frames;
+		xfer += frames;
+	}
+	return (snd_pcm_sframes_t)xfer;
+error:
+	return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
+}
+
+static snd_pcm_sframes_t snd_pcm_plugin_sync_hw_ptr(snd_pcm_t *pcm,
+						    snd_pcm_uframes_t slave_hw_ptr,
+						    snd_pcm_sframes_t slave_size)
+{
 	if (pcm->stream == SND_PCM_STREAM_CAPTURE &&
 	    pcm->access != SND_PCM_ACCESS_RW_INTERLEAVED &&
 	    pcm->access != SND_PCM_ACCESS_RW_NONINTERLEAVED)
-		goto _capture;
-        *pcm->hw.ptr = *slave->hw.ptr;
+		return snd_pcm_plugin_sync_hw_ptr_capture(pcm, slave_size);
+        *pcm->hw.ptr = slave_hw_ptr;
         return slave_size;
- _capture:
- 	{
-		const snd_pcm_channel_area_t *areas;
-		snd_pcm_uframes_t xfer, hw_offset, size;
-		
-		xfer = snd_pcm_mmap_capture_avail(pcm);
-		size = pcm->buffer_size - xfer;
-		areas = snd_pcm_mmap_areas(pcm);
-		hw_offset = snd_pcm_mmap_hw_offset(pcm);
-		while (size > 0 && slave_size > 0) {
-			snd_pcm_uframes_t frames = size;
-			snd_pcm_uframes_t cont = pcm->buffer_size - hw_offset;
-			const snd_pcm_channel_area_t *slave_areas;
-			snd_pcm_uframes_t slave_offset;
-			snd_pcm_uframes_t slave_frames = ULONG_MAX;
-			snd_pcm_sframes_t result;
-			/* As mentioned in the ALSA API (see pcm/pcm.c:942):
-			 * The function #snd_pcm_avail_update()
-			 * have to be called before any mmap begin+commit operation.
-			 * Otherwise the snd_pcm_areas_copy will not called a second time.
-			 * But this is needed, if the ring buffer wrap is reached and
-			 * there is more data available.
-			 */
-			slave_size = snd_pcm_avail_update(slave);
-			result = snd_pcm_mmap_begin(slave, &slave_areas, &slave_offset, &slave_frames);
-			if (result < 0) {
-				err = result;
-				goto error;
-			}
-			if (frames > cont)
-				frames = cont;
-			frames = (plugin->read)(pcm, areas, hw_offset, frames,
-					      slave_areas, slave_offset, &slave_frames);
-			result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
-			if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
-				snd_pcm_sframes_t res;
-				
-				res = plugin->undo_read(slave, areas, hw_offset, frames, slave_frames - result);
-				if (res < 0) {
-					err = res;
-					goto error;
-				}
-				frames -= res;
-			}
-			if (result <= 0) {
-				err = result;
-				goto error;
-			}
-			snd_pcm_mmap_hw_forward(pcm, frames);
-			if (frames == cont)
-				hw_offset = 0;
-			else
-				hw_offset += frames;
-			size -= frames;
-			slave_size -= slave_frames;
-			xfer += frames;
-		}
-		return (snd_pcm_sframes_t)xfer;
+}
 
-	error:
-		return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
-	}
+static snd_pcm_sframes_t snd_pcm_plugin_avail_update(snd_pcm_t *pcm)
+{
+	snd_pcm_plugin_t *plugin = pcm->private_data;
+	snd_pcm_t *slave = plugin->gen.slave;
+	snd_pcm_sframes_t slave_size;
+
+	slave_size = snd_pcm_avail_update(slave);
+	return snd_pcm_plugin_sync_hw_ptr(pcm, *slave->hw.ptr, slave_size);
 }
 
 static int snd_pcm_plugin_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
-- 
2.26.2