GetPreviousEntry
status_t GetPreviousEntry(void* key, uint16* keyLength,
status_t status = fIterator->GetPreviousEntry((void**)&entries,
status_t GetPreviousEntry(void** _value,
status_t GetPreviousEntry(Entry **entry) const;
status_t GetPreviousEntry(void *key,uint16 *keyLength,uint16 maxLength,off_t *value);