XXH64 family

Data Structures
struct	XXH64_canonical_t
	Canonical (big endian) representation of XXH64_hash_t. More...

Typedefs
typedef struct XXH64_state_s	XXH64_state_t
	The opaque state struct for the XXH64 streaming API.

Functions
XXH64_hash_t	XXH64 (XXH_NOESCAPE const void *input, size_t length, XXH64_hash_t seed)
	Calculates the 64-bit hash of input using xxHash64.
XXH64_state_t *	XXH64_createState (void)
	Allocates an XXH64_state_t.
XXH_errorcode	XXH64_freeState (XXH64_state_t *statePtr)
	Frees an XXH64_state_t.
void	XXH64_copyState (XXH_NOESCAPE XXH64_state_t *dst_state, const XXH64_state_t *src_state)
	Copies one XXH64_state_t to another.
XXH_errorcode	XXH64_reset (XXH_NOESCAPE XXH64_state_t *statePtr, XXH64_hash_t seed)
	Resets an XXH64_state_t to begin a new hash.
XXH_errorcode	XXH64_update (XXH_NOESCAPE XXH64_state_t *statePtr, XXH_NOESCAPE const void *input, size_t length)
	Consumes a block of input to an XXH64_state_t.
XXH64_hash_t	XXH64_digest (XXH_NOESCAPE const XXH64_state_t *statePtr)
	Returns the calculated hash value from an XXH64_state_t.
void	XXH64_canonicalFromHash (XXH_NOESCAPE XXH64_canonical_t *dst, XXH64_hash_t hash)
	Converts an XXH64_hash_t to a big endian XXH64_canonical_t.
XXH64_hash_t	XXH64_hashFromCanonical (XXH_NOESCAPE const XXH64_canonical_t *src)
	Converts an XXH64_canonical_t to a native XXH64_hash_t.

Detailed Description

Contains functions used in the classic 64-bit xxHash algorithm.

Note

XXH3 provides competitive speed for both 32-bit and 64-bit systems, and offers true 64/128 bit hash results. It provides better speed for systems with vector processing capabilities.

Typedef Documentation

XXH64_state_t

typedef struct XXH64_state_s XXH64_state_t

The opaque state struct for the XXH64 streaming API.

See also

XXH64_state_s for details.

Function Documentation

XXH64()

XXH64_hash_t XXH64	(	XXH_NOESCAPE const void *	input,
		size_t	length,
		XXH64_hash_t	seed
	)

Calculates the 64-bit hash of input using xxHash64.

This function usually runs faster on 64-bit systems, but slower on 32-bit systems (see benchmark).

Parameters

input	The block of data to be hashed, at least length bytes in size.
length	The length of input, in bytes.
seed	The 64-bit seed to alter the hash's output predictably.

Precondition

The memory between input and input + length must be valid, readable, contiguous memory. However, if length is 0, input may be NULL. In C++, this also must be TriviallyCopyable.

Returns

The calculated 64-bit hash.

See also

XXH32(), XXH3_64bits_withSeed(), XXH3_128bits_withSeed(), XXH128(): Direct equivalents for the other variants of xxHash.

XXH64_createState(), XXH64_update(), XXH64_digest(): Streaming version.

XXH64_createState()

XXH64_state_t * XXH64_createState

(

void

)

Allocates an XXH64_state_t.

Must be freed with XXH64_freeState().

Returns

An allocated XXH64_state_t on success, NULL on failure.

XXH64_freeState()

XXH_errorcode XXH64_freeState

(

XXH64_state_t *

statePtr

)

Frees an XXH64_state_t.

Must be allocated with XXH64_createState().

Parameters

statePtr

A pointer to an XXH64_state_t allocated with XXH64_createState().

Returns

XXH_OK.

XXH64_copyState()

void XXH64_copyState	(	XXH_NOESCAPE XXH64_state_t *	dst_state,
		const XXH64_state_t *	src_state
	)

Copies one XXH64_state_t to another.

Parameters

dst_state	The state to copy to.
src_state	The state to copy from.

Precondition

dst_state and src_state must not be NULL and must not overlap.

XXH64_reset()

XXH_errorcode XXH64_reset	(	XXH_NOESCAPE XXH64_state_t *	statePtr,
		XXH64_hash_t	seed
	)

Resets an XXH64_state_t to begin a new hash.

This function resets and seeds a state. Call it before XXH64_update().

Parameters

statePtr	The state struct to reset.
seed	The 64-bit seed to alter the hash result predictably.

Precondition

statePtr must not be NULL.

Returns

XXH_OK on success, XXH_ERROR on failure.

XXH64_update()

XXH_errorcode XXH64_update	(	XXH_NOESCAPE XXH64_state_t *	statePtr,
		XXH_NOESCAPE const void *	input,
		size_t	length
	)

Consumes a block of input to an XXH64_state_t.

Call this to incrementally consume blocks of data.

Parameters

statePtr	The state struct to update.
input	The block of data to be hashed, at least length bytes in size.
length	The length of input, in bytes.

Precondition

statePtr must not be NULL.

The memory between input and input + length must be valid, readable, contiguous memory. However, if length is 0, input may be NULL. In C++, this also must be TriviallyCopyable.

Returns

XXH_OK on success, XXH_ERROR on failure.

XXH64_digest()

XXH64_hash_t XXH64_digest

(

XXH_NOESCAPE const XXH64_state_t *

statePtr

)

Returns the calculated hash value from an XXH64_state_t.

Note

Calling XXH64_digest() will not affect statePtr, so you can update, digest, and update again.

Parameters

statePtr

The state struct to calculate the hash from.

Precondition

statePtr must not be NULL.

Returns

The calculated xxHash64 value from that state.

XXH64_canonicalFromHash()

void XXH64_canonicalFromHash	(	XXH_NOESCAPE XXH64_canonical_t *	dst,
		XXH64_hash_t	hash
	)

Converts an XXH64_hash_t to a big endian XXH64_canonical_t.

Parameters

dst	The XXH64_canonical_t pointer to be stored to.
hash	The XXH64_hash_t to be converted.

Precondition

dst must not be NULL.

XXH64_hashFromCanonical()

XXH64_hash_t XXH64_hashFromCanonical

(

XXH_NOESCAPE const XXH64_canonical_t *

src

)

Converts an XXH64_canonical_t to a native XXH64_hash_t.

Parameters

src	The XXH64_canonical_t to convert.

Precondition

src must not be NULL.

Returns

The converted hash.