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ALSA: core - Refactor card id string creation code
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The code to handle the card id string is fairly messy, so here is a
tidy up.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
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@tiwai
tiwai committed Mar 9, 2012
1 parent db05828 commit e7df2a3
Showing 1 changed file with 100 additions and 69 deletions.
169 changes: 100 additions & 69 deletions sound/core/init.c
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Original file line number Diff line number Diff line change
Expand Up @@ -480,74 +480,104 @@ int snd_card_free(struct snd_card *card)

EXPORT_SYMBOL(snd_card_free);

static void snd_card_set_id_no_lock(struct snd_card *card, const char *nid)
/* retrieve the last word of shortname or longname */
static const char *retrieve_id_from_card_name(const char *name)
{
int i, len, idx_flag = 0, loops = SNDRV_CARDS;
const char *spos, *src;
char *id;

if (nid == NULL) {
id = card->shortname;
spos = src = id;
while (*id != '\0') {
if (*id == ' ')
spos = id + 1;
id++;
}
} else {
spos = src = nid;
const char *spos = name;

while (*name) {
if (isspace(*name) && isalnum(name[1]))
spos = name + 1;
name++;
}
id = card->id;
while (*spos != '\0' && !isalnum(*spos))
spos++;
if (isdigit(*spos))
*id++ = isalpha(src[0]) ? src[0] : 'D';
while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
if (isalnum(*spos))
*id++ = *spos;
spos++;
return spos;
}

/* return true if the given id string doesn't conflict any other card ids */
static bool card_id_ok(struct snd_card *card, const char *id)
{
int i;
if (!snd_info_check_reserved_words(id))
return false;
for (i = 0; i < snd_ecards_limit; i++) {
if (snd_cards[i] && snd_cards[i] != card &&
!strcmp(snd_cards[i]->id, id))
return false;
}
*id = '\0';
return true;
}

id = card->id;
/* copy to card->id only with valid letters from nid */
static void copy_valid_id_string(struct snd_card *card, const char *src,
const char *nid)
{
char *id = card->id;

while (*nid && !isalnum(*nid))
nid++;
if (isdigit(*nid))
*id++ = isalpha(*src) ? *src : 'D';
while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
if (isalnum(*nid))
*id++ = *nid;
nid++;
}
*id = 0;
}

/* Set card->id from the given string
* If the string conflicts with other ids, add a suffix to make it unique.
*/
static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
const char *nid)
{
int len, loops;
bool with_suffix;
bool is_default = false;
char *id;

if (*id == '\0')
copy_valid_id_string(card, src, nid);
id = card->id;

again:
/* use "Default" for obviously invalid strings
* ("card" conflicts with proc directories)
*/
if (!*id || !strncmp(id, "card", 4)) {
strcpy(id, "Default");
is_default = true;
}

while (1) {
if (loops-- == 0) {
snd_printk(KERN_ERR "unable to set card id (%s)\n", id);
strcpy(card->id, card->proc_root->name);
return;
}
if (!snd_info_check_reserved_words(id))
goto __change;
for (i = 0; i < snd_ecards_limit; i++) {
if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
goto __change;
}
break;
with_suffix = false;
for (loops = 0; loops < SNDRV_CARDS; loops++) {
if (card_id_ok(card, id))
return; /* OK */

__change:
len = strlen(id);
if (idx_flag) {
if (id[len-1] != '9')
id[len-1]++;
else
id[len-1] = 'A';
} else if ((size_t)len <= sizeof(card->id) - 3) {
strcat(id, "_1");
idx_flag++;
if (!with_suffix) {
/* add the "_X" suffix */
char *spos = id + len;
if (len > sizeof(card->id) - 3)
spos = id + sizeof(card->id) - 3;
strcpy(spos, "_1");
with_suffix = true;
} else {
spos = id + len - 2;
if ((size_t)len <= sizeof(card->id) - 2)
spos++;
*(char *)spos++ = '_';
*(char *)spos++ = '1';
*(char *)spos++ = '\0';
idx_flag++;
/* modify the existing suffix */
if (id[len - 1] != '9')
id[len - 1]++;
else
id[len - 1] = 'A';
}
}
/* fallback to the default id */
if (!is_default) {
*id = 0;
goto again;
}
/* last resort... */
snd_printk(KERN_ERR "unable to set card id (%s)\n", id);
if (card->proc_root->name)
strcpy(card->id, card->proc_root->name);
}

/**
Expand All @@ -564,7 +594,7 @@ void snd_card_set_id(struct snd_card *card, const char *nid)
if (card->id[0] != '\0')
return;
mutex_lock(&snd_card_mutex);
snd_card_set_id_no_lock(card, nid);
snd_card_set_id_no_lock(card, nid, nid);
mutex_unlock(&snd_card_mutex);
}
EXPORT_SYMBOL(snd_card_set_id);
Expand Down Expand Up @@ -596,22 +626,12 @@ card_id_store_attr(struct device *dev, struct device_attribute *attr,
memcpy(buf1, buf, copy);
buf1[copy] = '\0';
mutex_lock(&snd_card_mutex);
if (!snd_info_check_reserved_words(buf1)) {
__exist:
if (!card_id_ok(NULL, buf1)) {
mutex_unlock(&snd_card_mutex);
return -EEXIST;
}
for (idx = 0; idx < snd_ecards_limit; idx++) {
if (snd_cards[idx] && !strcmp(snd_cards[idx]->id, buf1)) {
if (card == snd_cards[idx])
goto __ok;
else
goto __exist;
}
}
strcpy(card->id, buf1);
snd_info_card_id_change(card);
__ok:
mutex_unlock(&snd_card_mutex);

return count;
Expand Down Expand Up @@ -665,7 +685,18 @@ int snd_card_register(struct snd_card *card)
mutex_unlock(&snd_card_mutex);
return 0;
}
snd_card_set_id_no_lock(card, card->id[0] == '\0' ? NULL : card->id);
if (*card->id) {
/* make a unique id name from the given string */
char tmpid[sizeof(card->id)];
memcpy(tmpid, card->id, sizeof(card->id));
snd_card_set_id_no_lock(card, tmpid, tmpid);
} else {
/* create an id from either shortname or longname */
const char *src;
src = *card->shortname ? card->shortname : card->longname;
snd_card_set_id_no_lock(card, src,
retrieve_id_from_card_name(src));
}
snd_cards[card->number] = card;
mutex_unlock(&snd_card_mutex);
init_info_for_card(card);
Expand Down

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