ALSA: core - Refactor card id string creation code

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>

diff --git a/sound/core/init.c b/sound/core/init.c
index 3ac49b1b7cb82ac4c6c6632691efb9d3178cb09e..068cf08d3ffb82360e3e6ee4c24b78be3abde545 100644 (file)
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -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);
 }
 
 /**
@@ -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);
@@ -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;
@@ -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);