[alsa-devel] [PATCH v1 2/4] alsabat: parse the card and PCM ID for XRUN injections path

[Takashi Iwai]

On Thu, 31 Aug 2017 15:37:07 +0200,
Zhang Keqiao wrote:
> 
> This patch intends to parse the card ID and PCM ID of playback
> and capture, then replace it in the path macro.
> 
> Signed-off-by: Zhang Keqiao <keqiao.zhang at intel.com>
> ---
>  bat/bat.c    | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  bat/common.h |  3 +++
>  2 files changed, 72 insertions(+)
> 
> diff --git a/bat/bat.c b/bat/bat.c
> index bf6873a..b12e5d3 100644
> --- a/bat/bat.c
> +++ b/bat/bat.c
> @@ -127,6 +127,69 @@ static void get_sine_frequencies(struct bat *bat, char *freq)
>  	}
>  }
>  
> +/* parse the card and pcm ID of playback device and capture device */
> +/* Then we can get the path for specify device to do the XRUN injection */
> +static int parse_card_and_pcm_id(struct bat *bat)
> +{
> +	char *tmp1;
> +	char *tmp2;
> +	char playback_device[MAX_DEV];
> +	char capture_device[MAX_DEV];
> +
> +	strcpy(playback_device, bat->playback.device);
> +	strcpy(capture_device, bat->capture.device);
> +
> +	if (bat->playback.device == bat->capture.device) {
> +		tmp1 = strchr(playback_device, ',');
> +		if (tmp1 != NULL) {
> +			*tmp1 = '\0';
> +			bat->playback.pcm_id = bat->capture.pcm_id = (tmp1 + 1);
> +		} else {
> +			fprintf(bat->err, _("err, cannot find the pcm ID\n"));
> +			return -EINVAL;
> +		}
> +		tmp2 = strchr(playback_device, ':');
> +		if (tmp2 != NULL) {
> +			bat->playback.card_id = bat->capture.card_id = (tmp2 + 1);
> +		} else {
> +			fprintf(bat->err, _("err, cannot find the card ID\n"));
> +			return -EINVAL;
> +		}
> +	} else {
> +		tmp1 = strchr(playback_device, ',');
> +		if (tmp1 != NULL) {
> +			*tmp1 = '\0';
> +			bat->playback.pcm_id = (tmp1 + 1);
> +		} else {
> +			fprintf(bat->err, _("err, cannot find the pcm ID of playback\n"));
> +			return -EINVAL;
> +		}
> +		tmp2 = strchr(playback_device, ':');
> +		if (tmp2 != NULL)
> +			bat->playback.card_id = (tmp2 + 1);
> +		else {
> +			fprintf(bat->err, _("err, cannot find the card ID of playback\n"));
> +			return -EINVAL;
> +		}
> +		tmp1 = strchr(capture_device, ',');
> +		if (tmp1 != NULL) {
> +			*tmp1 = '\0';
> +			bat->capture.pcm_id = (tmp1 + 1);
> +		} else {
> +			fprintf(bat->err, _("err, cannot find the pcm ID of capture"));
> +			return -EINVAL;
> +		}
> +		tmp2 = strchr(capture_device, ':');
> +		if (tmp2 != NULL)
> +			bat->capture.card_id = (tmp2 + 1);
> +		else {
> +			fprintf(bat->err, _("err, cannot find the card ID of capture"));
> +			return -EINVAL;
> +		}
> +	}

FYI, a handy function for this kind of parsing is sscanf().
For example, the above can be a simple form like:

	if (sscanf(bat->playback.device, "pcm:%d,%d", &card, &pcm) != 2)
		return -EINVAL;


thanks,

Takashi