Here are the data structures with brief descriptions:

C_HashTable	A hash table mapping keys to values using separate chaining
C_HashTableEntry	An entry in a hash table, storing a key-value pair and a chain link
C_HashTableIterator
C_HashTablePair
C_Queue	A double-ended queue (deque) backed by a doubly-linked list
C_QueueEntry	A single node in a double-ended queue
Ceventpoint	An event point is a combination of a frequency bin, time bin and magnitude
Cextracted_event_points	The result of event point extraction is a list of event points
Cextracted_fingerprints	The result of fingerprint extraction: a list of fingerprints with a size
Cfingerprint	A fingerprint is a combination of three event points each with a frequency bin, time bin and magnitude
Cmatch_result	Represents a single fingerprint match result between a query and a reference
COlaf_Config	Configuration parameters defining the behaviour of Olaf
COlaf_DB	A struct with state information on the data store
COlaf_Deque	Contains state information related to the deque
COlaf_EP_Extractor	Contains state information for event point (EP) extraction
COlaf_FFT	An opaque struct with state information related to the fft
COlaf_FP_DB_Writer	An opaque struct with state information related to the stream processor
COlaf_FP_DB_Writer_Cache	An opaque struct with state information related to the cache writer
COlaf_FP_Extractor	State information for the fingerprint extractor
COlaf_FP_File_Writer	A struct to keep the internal state of the file writer hidden. It should not be used in other places
COlaf_FP_Matcher	A matcher matches extracted fingerprints with a database. A struct to keep the internal state of the matcher hidden and should not be used in other places
COlaf_Reader	The state information
COlaf_Resource_Meta_data	A struct containing meta data on indexed audio files
COlaf_Runner	Helps to run query, store, delete or print commands. These share a lot of functionality but differ in crucial parts. To keep this organized the runner keeps some shared state
COlaf_State	Holds the complete processing state for the WASM-based Olaf instance
COlaf_Stream_Processor	An opaque struct with state information related to the stream processor
CPFFFT_Setup	Internal state for a PFFFT transform instance