[alsa-devel] [RFCv3][PATCH 29/39] axfer: add options for plugins in alsa-lib

[Takashi Sakamoto]

As of 2017, two userspace library implementations are known; alsa-lib and
tinyalsa. The latter is simple I/O library to use ALSA PCM interface. On
the other hand, alsa-lib is more complicated than it. This is because it's
designed to add features to transmission of data frames; e.g. sample
resampling. To achieve this, alsa-lib has its configuration space and
plugin system.

In aplay, some options are implemented as a flag for the plugins in
alsa-lib. The flag is given to snd_pcm_open(). This commit adds support
for the flags.

Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
 axfer/options.c        | 17 +++++++++++++++++
 axfer/options.h        |  6 ++++++
 axfer/xfer-libasound.c |  8 ++++++++
 3 files changed, 31 insertions(+)

diff --git a/axfer/options.c b/axfer/options.c
index a22223a0..bca87d14 100644
--- a/axfer/options.c
+++ b/axfer/options.c
@@ -19,6 +19,10 @@ enum no_short_opts {
 	OPT_TEST_NOWAIT,
 	OPT_PERIOD_SIZE,
 	OPT_BUFFER_SIZE,
+	OPT_DISABLE_RESAMPLE,
+	OPT_DISABLE_CHANNELS,
+	OPT_DISABLE_FORMAT,
+	OPT_DISABLE_SOFTVOL,
 	/* Obsoleted. */
 	OPT_MAX_FILE_TIME,
 };
@@ -348,6 +352,11 @@ int context_options_init(struct context_options *opts, int argc,
 		{"avail-min",		1, 0, 'A'},
 		{"start-delay",		1, 0, 'R'},
 		{"stop-delay",		1, 0, 'T'},
+		/* For plugins in alsa-lib. */
+		{"disable-resample",	0, 0, OPT_DISABLE_RESAMPLE},
+		{"disable-channels",	0, 0, OPT_DISABLE_CHANNELS},
+		{"disable-format",	0, 0, OPT_DISABLE_FORMAT},
+		{"disable-softvol",	0, 0, OPT_DISABLE_SOFTVOL},
 		/* For debugging. */
 		{"dump-hw-params",	0, 0, OPT_DUMP_HW_PARAMS},
 		{"fatal-errors",	0, 0, OPT_FATAL_ERRORS},
@@ -409,6 +418,14 @@ int context_options_init(struct context_options *opts, int argc,
 			opts->msec_for_start_threshold = parse_l(optarg, &err);
 		else if (c == 'T')
 			opts->msec_for_stop_threshold = parse_l(optarg, &err);
+		else if (c == OPT_DISABLE_RESAMPLE)
+			opts->no_auto_resample = true;
+		else if (c == OPT_DISABLE_CHANNELS)
+			opts->no_auto_channels = true;
+		else if (c == OPT_DISABLE_FORMAT)
+			opts->no_auto_format = true;
+		else if (c == OPT_DISABLE_SOFTVOL)
+			opts->no_softvol = true;
 		else if (c == OPT_DUMP_HW_PARAMS)
 			opts->dump_hw_params = true;
 		else if (c == OPT_FATAL_ERRORS)
diff --git a/axfer/options.h b/axfer/options.h
index 63b36364..95012ad3 100644
--- a/axfer/options.h
+++ b/axfer/options.h
@@ -45,6 +45,12 @@ struct context_options {
 	unsigned int msec_for_start_threshold;
 	unsigned int msec_for_stop_threshold;
 
+	/* For plugins in alsa-lib. */
+	bool no_auto_resample;
+	bool no_auto_channels;
+	bool no_auto_format;
+	bool no_softvol;
+
 	/* For debugging. */
 	bool dump_hw_params;
 	bool finish_at_xrun;
diff --git a/axfer/xfer-libasound.c b/axfer/xfer-libasound.c
index 533c9492..e01327e2 100644
--- a/axfer/xfer-libasound.c
+++ b/axfer/xfer-libasound.c
@@ -15,6 +15,14 @@ static int get_mode(struct context_options *options)
 
 	if (options->nonblock)
 		mode |= SND_PCM_NONBLOCK;
+	if (options->no_auto_resample)
+		mode |= SND_PCM_NO_AUTO_RESAMPLE;
+	if (options->no_auto_channels)
+		mode |= SND_PCM_NO_AUTO_CHANNELS;
+	if (options->no_auto_format)
+		mode |= SND_PCM_NO_AUTO_FORMAT;
+	if (options->no_softvol)
+		mode |= SND_PCM_NO_SOFTVOL;
 
 	return mode;
 }
-- 
2.11.0