int
mi_rprev(MI_INFO * info, byte * buf, int inx)
{
int error , changed;
register uint flag;
MYISAM_SHARE *share = info->s;
DBUG_ENTER("mi_rprev");
if ((inx = _mi_check_index(info, inx)) < 0)
DBUG_RETURN(my_errno);
flag = SEARCH_SMALLER; /* Read previous */
if (info->lastpos == HA_OFFSET_ERROR && info->update & HA_STATE_NEXT_FOUND)
flag = 0; /* Read last */
if (_mi_readinfo(info, F_RDLCK, 1))
DBUG_RETURN(my_errno);
changed = _mi_test_if_changed(info);
if (share->concurrent_insert)
rw_rdlock(&share->key_root_lock[inx]);
if (!flag)
error = _mi_search_last(info, share->keyinfo + inx,
share->state.key_root[inx]);
else if (!changed)
error = _mi_search_next(info, share->keyinfo + inx, info->lastkey,
info->lastkey_length, flag,
share->state.key_root[inx]);
else
error = _mi_search(info, share->keyinfo + inx, info->lastkey,
info->lastkey_length, flag, share->state.key_root[inx]);
if (!error) {
while (info->lastpos >= info->state->data_file_length) {
/*
* Skip rows that are inserted by other threads since
* we got a lock
*/
if ((error = _mi_search_next(info, share->keyinfo + inx, info->lastkey,
info->lastkey_length,
SEARCH_SMALLER,
share->state.key_root[inx])))
break;
}
}
if (share->concurrent_insert)
rw_unlock(&share->key_root_lock[inx]);
info->update &= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
info->update |= HA_STATE_PREV_FOUND;
if (error) {
if (my_errno == HA_ERR_KEY_NOT_FOUND)
my_errno = HA_ERR_END_OF_FILE;
} else if (!buf) {
DBUG_RETURN(info->lastpos == HA_OFFSET_ERROR ? my_errno : 0);
} else if (!(*info->read_record) (info, info->lastpos, buf)) {
info->update |= HA_STATE_AKTIV; /* Record is read */
DBUG_RETURN(0);
}
DBUG_RETURN(my_errno);
} /* mi_rprev */
int mi_rprev(MI_INFO *info, uchar *buf, int inx)
{
int error,changed;
register uint flag;
MYISAM_SHARE *share=info->s;
DBUG_ENTER("mi_rprev");
if ((inx = _mi_check_index(info,inx)) < 0)
DBUG_RETURN(my_errno);
flag=SEARCH_SMALLER; /* Read previous */
if (info->lastpos == HA_OFFSET_ERROR && info->update & HA_STATE_NEXT_FOUND)
flag=0; /* Read last */
if (fast_mi_readinfo(info))
DBUG_RETURN(my_errno);
changed=_mi_test_if_changed(info);
if (share->concurrent_insert)
mysql_rwlock_rdlock(&share->key_root_lock[inx]);
if (!flag)
error=_mi_search_last(info, share->keyinfo+inx,
share->state.key_root[inx]);
else if (!changed)
error=_mi_search_next(info,share->keyinfo+inx,info->lastkey,
info->lastkey_length,flag,
share->state.key_root[inx]);
else
error=_mi_search(info,share->keyinfo+inx,info->lastkey,
USE_WHOLE_KEY, flag, share->state.key_root[inx]);
if (!error)
{
int res= 0;
while ((share->concurrent_insert &&
info->lastpos >= info->state->data_file_length) ||
(info->index_cond_func &&
!(res= mi_check_index_cond(info, inx, buf))))
{
/*
Skip rows that are either inserted by other threads since
we got a lock or do not match pushed index conditions
*/
if ((error=_mi_search_next(info,share->keyinfo+inx,info->lastkey,
info->lastkey_length,
SEARCH_SMALLER,
share->state.key_root[inx])))
break;
}
if (!error && res == 2)
{
if (share->concurrent_insert)
mysql_rwlock_unlock(&share->key_root_lock[inx]);
info->lastpos= HA_OFFSET_ERROR;
DBUG_RETURN(my_errno= HA_ERR_END_OF_FILE);
}
}
if (share->concurrent_insert)
{
if (!error)
{
while (info->lastpos >= info->state->data_file_length)
{
/* Skip rows that are inserted by other threads since we got a lock */
if ((error=_mi_search_next(info,share->keyinfo+inx,info->lastkey,
info->lastkey_length,
SEARCH_SMALLER,
share->state.key_root[inx])))
break;
}
}
mysql_rwlock_unlock(&share->key_root_lock[inx]);
}
info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
info->update|= HA_STATE_PREV_FOUND;
if (error)
{
if (my_errno == HA_ERR_KEY_NOT_FOUND)
my_errno=HA_ERR_END_OF_FILE;
}
else if (!buf)
{
DBUG_RETURN(info->lastpos==HA_OFFSET_ERROR ? my_errno : 0);
}
else if (!(*info->read_record)(info,info->lastpos,buf))
{
info->update|= HA_STATE_AKTIV; /* Record is read */
DBUG_RETURN(0);
}
DBUG_RETURN(my_errno);
} /* mi_rprev */