[alsa-devel] [PATCH 1/3] pcm: add support to get PCM sample rate from name

[guneshwor.o.singh at intel.com]

From: Guneshwor Singh <guneshwor.o.singh at intel.com>

Get PCM sample rate from rate name similar to snd_pcm_format_value() which
retrieves format from format name.

Signed-off-by: Guneshwor Singh <guneshwor.o.singh at intel.com>
---
 include/pcm.h | 38 ++++++++++++++++++++++++++++++++++++++
 src/pcm/pcm.c | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+)

diff --git a/include/pcm.h b/include/pcm.h
index 0be1a321..81bc55b1 100644
--- a/include/pcm.h
+++ b/include/pcm.h
@@ -119,6 +119,43 @@ typedef enum _snd_pcm_access {
 	SND_PCM_ACCESS_LAST = SND_PCM_ACCESS_RW_NONINTERLEAVED
 } snd_pcm_access_t;
 
+/** PCM sample rate */
+typedef enum _snd_pcm_rates {
+	/** Unknown */
+	SND_PCM_RATE_UNKNOWN = -1,
+	/** 5512 Hz sample rate */
+	SND_PCM_RATE_5512 = 0,
+	/** 8000 Hz sample rate */
+	SND_PCM_RATE_8000,
+	/** 11025 Hz sample rate */
+	SND_PCM_RATE_11025,
+	/** 16000 Hz sample rate */
+	SND_PCM_RATE_16000,
+	/** 22050 Hz sample rate */
+	SND_PCM_RATE_22050,
+	/** 32000 Hz sample rate */
+	SND_PCM_RATE_32000,
+	/** 44100 Hz sample rate */
+	SND_PCM_RATE_44100,
+	/** 48000 Hz sample rate */
+	SND_PCM_RATE_48000,
+	/** 64000 Hz sample rate */
+	SND_PCM_RATE_64000,
+	/** 88200 Hz sample rate */
+	SND_PCM_RATE_88200,
+	/** 96000 Hz sample rate */
+	SND_PCM_RATE_96000,
+	/** 176400 Hz sample rate */
+	SND_PCM_RATE_176400,
+	/** 192000 Hz sample rate */
+	SND_PCM_RATE_192000,
+	/** continuous range within rate_min and rate_max */
+	SND_PCM_RATE_CONTINUOUS = 30,
+	/** more continuous range */
+	SND_PCM_RATE_KNOT = 31,
+	SND_PCM_RATE_LAST = SND_PCM_RATE_KNOT,
+} snd_pcm_rates_t;
+
 /** PCM sample format */
 typedef enum _snd_pcm_format {
 	/** Unknown */
@@ -1047,6 +1084,7 @@ const char *snd_pcm_format_description(const snd_pcm_format_t format);
 const char *snd_pcm_subformat_name(const snd_pcm_subformat_t subformat);
 const char *snd_pcm_subformat_description(const snd_pcm_subformat_t subformat);
 snd_pcm_format_t snd_pcm_format_value(const char* name);
+snd_pcm_rates_t snd_pcm_rate_value(const char* name);
 const char *snd_pcm_tstamp_mode_name(const snd_pcm_tstamp_t mode);
 const char *snd_pcm_state_name(const snd_pcm_state_t state);
 
diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c
index 200b10c2..bff1b949 100644
--- a/src/pcm/pcm.c
+++ b/src/pcm/pcm.c
@@ -1722,6 +1722,7 @@ static int __snd_pcm_poll_revents(snd_pcm_t *pcm, struct pollfd *pfds,
 #define START(v) [SND_PCM_START_##v] = #v
 #define HW_PARAM(v) [SND_PCM_HW_PARAM_##v] = #v
 #define SW_PARAM(v) [SND_PCM_SW_PARAM_##v] = #v
+#define RATE(v) [SND_PCM_RATE_##v] = #v
 #define FORMAT(v) [SND_PCM_FORMAT_##v] = #v
 #define SUBFORMAT(v) [SND_PCM_SUBFORMAT_##v] = #v 
 
@@ -1754,6 +1755,24 @@ static const char *const snd_pcm_access_names[] = {
 	ACCESS(RW_NONINTERLEAVED),
 };
 
+static const char *const snd_pcm_rate_names[] = {
+	RATE(5512),
+	RATE(8000),
+	RATE(11025),
+	RATE(16000),
+	RATE(22050),
+	RATE(32000),
+	RATE(44100),
+	RATE(48000),
+	RATE(64000),
+	RATE(88200),
+	RATE(96000),
+	RATE(176400),
+	RATE(192000),
+	RATE(CONTINUOUS),
+	RATE(KNOT),
+};
+
 static const char *const snd_pcm_format_names[] = {
 	FORMAT(S8),
 	FORMAT(U8),
@@ -1978,6 +1997,24 @@ const char *snd_pcm_format_description(snd_pcm_format_t format)
 }
 
 /**
+ * \brief get PCM sample rate from name
+ * \param name PCM sample rate name (case insensitive)
+ * \return PCM sample rate
+ */
+snd_pcm_rates_t snd_pcm_rate_value(const char* name)
+{
+	snd_pcm_rates_t rate;
+	for (rate = 0; rate <= SND_PCM_RATE_LAST; rate++) {
+		if (snd_pcm_rate_names[rate] &&
+		    strcasecmp(name, snd_pcm_rate_names[rate]) == 0) {
+			return rate;
+		}
+	}
+
+	return SND_PCM_RATE_UNKNOWN;
+}
+
+/**
  * \brief get PCM sample format from name
  * \param name PCM sample format name (case insensitive)
  * \return PCM sample format
-- 
2.13.0