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

[Takashi Iwai]

On Wed, 31 May 2017 15:46:44 +0200,
<guneshwor.o.singh at intel.com> wrote:
> 
> 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>

The enum is only for internal, so it shouldn't be exposed as a public
API.  I don't mind if it's only for alsa-lib internals, though.


thanks,

Takashi

> ---
>  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
> 
>