Added function, mixer_get_num_ctls_by_name

This function is used to get the number of mixer controls by a given name.
It was added for use with mixer_get_ctl_by_name_and_index so that client code
can expect the last valid index to pass.

2 files changed, 26 insertions, 0 deletions

diff --git a/include/tinyalsa/mixer.h b/include/tinyalsa/mixer.h
index a54b5c1..f743f6e 100644
--- a/include/tinyalsa/mixer.h
+++ b/include/tinyalsa/mixer.h
@@ -73,6 +73,8 @@ const char *mixer_get_name(const struct mixer *mixer);
 
 unsigned int mixer_get_num_ctls(const struct mixer *mixer);
 
+unsigned int mixer_get_num_ctls_by_name(const struct mixer *mixer, const char *name);
+
 const struct mixer_ctl *mixer_get_ctl_const(const struct mixer *mixer, unsigned int id);
 
 struct mixer_ctl *mixer_get_ctl(struct mixer *mixer, unsigned int id);
diff --git a/src/mixer.c b/src/mixer.c
index 4bb1756..9e661c5 100644
--- a/src/mixer.c
+++ b/src/mixer.c
@@ -194,6 +194,30 @@ unsigned int mixer_get_num_ctls(const struct mixer *mixer)
     return mixer->count;
 }
 
+/** Gets the number of mixer controls, that go by a specified name, for a given mixer.
+ * @param mixer An initialized mixer handle.
+ * @param name The name of the mixer control
+ * @returns The number of mixer controls, specified by @p name, for the given mixer.
+ * @ingroup libtinyalsa-mixer
+ */
+unsigned int mixer_get_num_ctls_by_name(const struct mixer *mixer, const char *name)
+{
+    unsigned int n;
+    unsigned int count = 0;
+    struct mixer_ctl *ctl;
+
+    if (!mixer)
+        return 0;
+
+    ctl = mixer->ctl;
+
+    for (n = 0; n < mixer->count; n++)
+        if (!strcmp(name, (char*) ctl[n].info.id.name))
+            count++;
+
+    return count;
+}
+
 /** Gets a mixer control handle, by the mixer control's id.
  * For non-const access, see @ref mixer_get_ctl
  * @param mixer An initialized mixer handle.