Merge pull request #52 from rfvirgil/get_id

mixer: Add mixer_ctl_get_id

2 files changed, 13 insertions, 0 deletions

diff --git a/include/tinyalsa/asoundlib.h b/include/tinyalsa/asoundlib.h
index a85e810..584cfe1 100644
--- a/include/tinyalsa/asoundlib.h
+++ b/include/tinyalsa/asoundlib.h
@@ -225,6 +225,7 @@ struct mixer_ctl *mixer_get_ctl(struct mixer *mixer, unsigned int id);
 struct mixer_ctl *mixer_get_ctl_by_name(struct mixer *mixer, const char *name);
 
 /* Get info about mixer controls */
+unsigned int mixer_ctl_get_id(struct mixer_ctl *ctl);
 const char *mixer_ctl_get_name(struct mixer_ctl *ctl);
 enum mixer_ctl_type mixer_ctl_get_type(struct mixer_ctl *ctl);
 const char *mixer_ctl_get_type_string(struct mixer_ctl *ctl);
diff --git a/mixer.c b/mixer.c
index 73ae6da..113f11e 100644
--- a/mixer.c
+++ b/mixer.c
@@ -33,6 +33,7 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <ctype.h>
+#include <limits.h>
 
 #include <sys/ioctl.h>
 
@@ -209,6 +210,17 @@ void mixer_ctl_update(struct mixer_ctl *ctl)
     ioctl(ctl->mixer->fd, SNDRV_CTL_IOCTL_ELEM_INFO, ctl->info);
 }
 
+unsigned int mixer_ctl_get_id(struct mixer_ctl *ctl)
+{
+    if (!ctl)
+        return UINT_MAX;
+
+    /* numid values start at 1, return a 0-base value that
+     * can be passed to mixer_get_ctl()
+     */
+    return ctl->info->id.numid - 1;
+}
+
 const char *mixer_ctl_get_name(struct mixer_ctl *ctl)
 {
     if (!ctl)