control: add snd_ctl_elem_id_compare() function

Compare two control element identifiers like strcmp().

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Jaroslav Kysela 2021-02-26 20:30:58 +01:00
parent 7a1402cddc
commit 2cfe6addae
2 changed files with 27 additions and 0 deletions

View file

@ -1818,6 +1818,32 @@ void snd_ctl_elem_id_copy(snd_ctl_elem_id_t *dst, const snd_ctl_elem_id_t *src)
*dst = *src;
}
/**
* \brief compare one #snd_ctl_elem_id_t to another
* \param id1 pointer to first id
* \param id2 pointer to second id
* \retval zero when values are identical, -1 first id
*/
int snd_ctl_elem_id_compare(snd_ctl_elem_id_t *id1, const snd_ctl_elem_id_t *id2)
{
int d;
assert(id1 && id2);
d = id1->iface - id2->iface;
if (d != 0)
return d;
d = id1->device - id2->device;
if (d != 0)
return d;
d = id2->subdevice - id2->subdevice;
if (d != 0)
return d;
d = strcmp((const char *)id1->name, (const char *)id2->name);
if (d != 0)
return d;
return id1->index - id2->index;
}
/**
* \brief Get numeric identifier from a CTL element identifier
* \param obj CTL element identifier