char *
db_nextrec(DB *db, char *key)
{
char c, *ptr;
/* We read lock the free list so that we don't read
a record in the middle of its being deleted. */
if (readw_lock(db->idxfd, FREE_OFF, SEEK_SET, 1) < 0)
err_dump("readw_lock error");
do {
/* read next sequential index record */
if (_db_readidx(db, 0) < 0) {
ptr = NULL; /* end of index file, EOF */
goto doreturn;
}
/* check if key is all blank (empty record) */
ptr = db->idxbuf;
while ( (c = *ptr++) != 0 && c == ' ')
; /* skip until null byte or nonblank */
} while (c == 0); /* loop until a nonblank key is found */
if (key != NULL)
strcpy(key, db->idxbuf); /* return key */
ptr = _db_readdat(db); /* return pointer to data buffer */
db->cnt_nextrec++;
doreturn:
if (un_lock(db->idxfd, FREE_OFF, SEEK_SET, 1) < 0)
err_dump("un_lock error");
return(ptr);
}
/* Returning the sequential record...
Just gotta step ahead through the index file where we gotta ignore deleted records.
db_rewind() essential to be called before this function at initial stage itself */
char *db_nextrec(DB *db, char *key)
{
char c, *ptr;
/* Locking the free list where we don't actually read a record in the mid of deletion*/
if(readw_lock(db->idxfd, FREE_OFF, SEEK_SET, 1) < 0)
err_dump("error");
do
{
/* read next sequential index record */
if(_db_readidx(db, 0) < 0)
{
ptr = NULL; /* end of index file --- EOF */
goto doreturn;
}
/* Checking if the key is still blank or empty record */
ptr = db->idxbuf;
while((c = *ptr++) != 0 && c = ' ');
/* skip if it's not blank */
}
while(c == 0) /* loop untill a non-empty key is found*/
if(key != NULL)
strcpy(key, db->idxbuf); /* return key */
ptr = _db_readdat(db); /* return pointer to data buffer */
db->cnt_nextrec++;
doreturn:
if(un_lock(db->idxfd, FREE_OFF, SEEK_SET, 1) < 0)
err_dump("error");
}
char *
db_fetch(DB *db, const char *key)
{
char *ptr;
if (_db_find(db, key, 0) < 0) {
ptr = NULL; /* error, record not found */
db->cnt_fetcherr++;
} else {
ptr = _db_readdat(db); /* return pointer to data */
db->cnt_fetchok++;
}
/* Unlock the hash chain that _db_find() locked */
if (un_lock(db->idxfd, db->chainoff, SEEK_SET, 1) < 0)
err_dump("un_lock error");
return(ptr);
}