int my_sortcmp(const char *s, const char *t, uint len)
{
#ifdef USE_STRCOLL
if (use_strcoll(default_charset_info))
return my_strnncoll(default_charset_info,
(uchar *)s, len, (uchar *)t, len);
else
#endif
{
while (len--)
{
if (my_sort_order[(uchar) *s++] != my_sort_order[(uchar) *t++])
return ((int) my_sort_order[(uchar) s[-1]] -
(int) my_sort_order[(uchar) t[-1]]);
}
return 0;
}
}
/*
DESCRIPTION
Search for hashnr/key/keylen in the list starting from 'head' and
position the cursor. The list is ORDER BY hashnr, key
RETURN
0 - not found
1 - found
NOTE
cursor is positioned in either case
pins[0..2] are used, they are NOT removed on return
*/
static int lfind(LF_SLIST * volatile *head, CHARSET_INFO *cs, uint32 hashnr,
const uchar *key, uint keylen, CURSOR *cursor, LF_PINS *pins)
{
uint32 cur_hashnr;
const uchar *cur_key;
uint cur_keylen;
intptr link;
retry:
cursor->prev= (intptr *)head;
do { /* PTR() isn't necessary below, head is a dummy node */
cursor->curr= (LF_SLIST *)(*cursor->prev);
_lf_pin(pins, 1, cursor->curr);
} while (*cursor->prev != (intptr)cursor->curr && LF_BACKOFF);
for (;;)
{
if (unlikely(!cursor->curr))
return 0; /* end of the list */
do {
/* QQ: XXX or goto retry ? */
link= cursor->curr->link;
cursor->next= PTR(link);
_lf_pin(pins, 0, cursor->next);
} while (link != cursor->curr->link && LF_BACKOFF);
cur_hashnr= cursor->curr->hashnr;
cur_key= cursor->curr->key;
cur_keylen= cursor->curr->keylen;
if (*cursor->prev != (intptr)cursor->curr)
{
(void)LF_BACKOFF;
goto retry;
}
if (!DELETED(link))
{
if (cur_hashnr >= hashnr)
{
int r= 1;
if (cur_hashnr > hashnr ||
(r= my_strnncoll(cs, (uchar*) cur_key, cur_keylen, (uchar*) key,
keylen)) >= 0)
return !r;
}
cursor->prev= &(cursor->curr->link);
_lf_pin(pins, 2, cursor->curr);
}
else
{
/*
we found a deleted node - be nice, help the other thread
and remove this deleted node
*/
if (my_atomic_casptr((void **) cursor->prev,
(void **)(char*) &cursor->curr, cursor->next))
_lf_alloc_free(pins, cursor->curr);
else
{
(void)LF_BACKOFF;
goto retry;
}
}
cursor->curr= cursor->next;
_lf_pin(pins, 1, cursor->curr);
}
}
/** walk the list, searching for an element or invoking a callback
Search for hashnr/key/keylen in the list starting from 'head' and
position the cursor. The list is ORDER BY hashnr, key
@param head start walking the list from this node
@param cs charset for comparing keys, NULL if callback is used
@param hashnr hash number to search for
@param key key to search for OR data for the callback
@param keylen length of the key to compare, 0 if callback is used
@param cursor for returning the found element
@param pins see lf_alloc-pin.c
@param callback callback action, invoked for every element
@note
cursor is positioned in either case
pins[0..2] are used, they are NOT removed on return
callback might see some elements twice (because of retries)
@return
if find: 0 - not found
1 - found
if callback:
0 - ok
1 - error (callbck returned 1)
*/
static int l_find(LF_SLIST * volatile *head, CHARSET_INFO *cs, uint32 hashnr,
const uchar *key, uint keylen, CURSOR *cursor, LF_PINS *pins,
my_hash_walk_action callback)
{
uint32 cur_hashnr;
const uchar *cur_key;
uint cur_keylen;
intptr link;
DBUG_ASSERT(!cs || !callback); /* should not be set both */
DBUG_ASSERT(!keylen || !callback); /* should not be set both */
retry:
cursor->prev= (intptr *)head;
do { /* PTR() isn't necessary below, head is a dummy node */
cursor->curr= (LF_SLIST *)(*cursor->prev);
lf_pin(pins, 1, cursor->curr);
} while (*cursor->prev != (intptr)cursor->curr && LF_BACKOFF);
for (;;)
{
if (unlikely(!cursor->curr))
return 0; /* end of the list */
cur_hashnr= cursor->curr->hashnr;
cur_keylen= cursor->curr->keylen;
cur_key= cursor->curr->key;
do {
link= cursor->curr->link;
cursor->next= PTR(link);
lf_pin(pins, 0, cursor->next);
} while (link != cursor->curr->link && LF_BACKOFF);
if (!DELETED(link))
{
if (unlikely(callback))
{
if (cur_hashnr & 1 && callback(cursor->curr + 1, (void*)key))
return 1;
}
else if (cur_hashnr >= hashnr)
{
int r= 1;
if (cur_hashnr > hashnr ||
(r= my_strnncoll(cs, cur_key, cur_keylen, key, keylen)) >= 0)
return !r;
}
cursor->prev= &(cursor->curr->link);
if (!(cur_hashnr & 1)) /* dummy node */
head= (LF_SLIST **)cursor->prev;
lf_pin(pins, 2, cursor->curr);
}
else
{
/*
we found a deleted node - be nice, help the other thread
and remove this deleted node
*/
if (my_atomic_casptr((void **) cursor->prev,
(void **) &cursor->curr, cursor->next) && LF_BACKOFF)
lf_alloc_free(pins, cursor->curr);
else
goto retry;
}
cursor->curr= cursor->next;
lf_pin(pins, 1, cursor->curr);
}
}
