XXH32 family

Classes
struct	XXH32_canonical_t
	Canonical (big endian) representation of XXH32_hash_t. More...

Macros
#define	XXH32_createState(void)   XXH_NAME2(XXH_NAMESPACE, XXH32_createState)
	Allocates an XXH32_state_t. More...
#define	XXH32_state_t   XXH_IPREF(XXH32_state_t)
	The opaque state struct for the XXH32 streaming API. More...

Typedefs
typedef struct XXH32_state_s	XXH32_state_t

Functions
XXH_PUBLIC_API XXH_PUREF XXH32_hash_t	XXH32 (const void *input, size_t length, XXH32_hash_t seed)
	Calculates the 32-bit hash of input using xxHash32. More...
XXH_PUBLIC_API XXH_errorcode	XXH32_freeState (XXH32_state_t *statePtr)
	Frees an XXH32_state_t. More...
XXH_PUBLIC_API void	XXH32_copyState (XXH32_state_t *dst_state, const XXH32_state_t *src_state)
	Copies one XXH32_state_t to another. More...
XXH_PUBLIC_API XXH_errorcode	XXH32_reset (XXH32_state_t *statePtr, XXH32_hash_t seed)
	Resets an XXH32_state_t to begin a new hash. More...
XXH_PUBLIC_API XXH_errorcode	XXH32_update (XXH32_state_t *statePtr, const void *input, size_t length)
	Consumes a block of input to an XXH32_state_t. More...
XXH_PUBLIC_API XXH_PUREF XXH32_hash_t	XXH32_digest (const XXH32_state_t *statePtr)
	Returns the calculated hash value from an XXH32_state_t. More...
XXH_PUBLIC_API void	XXH32_canonicalFromHash (XXH32_canonical_t *dst, XXH32_hash_t hash)
	Converts an XXH32_hash_t to a big endian XXH32_canonical_t. More...
XXH_PUBLIC_API XXH_PUREF XXH32_hash_t	XXH32_hashFromCanonical (const XXH32_canonical_t *src)
	Converts an XXH32_canonical_t to a native XXH32_hash_t. More...

Detailed Description

Contains functions used in the classic 32-bit xxHash algorithm.

Note

XXH32 is useful for older platforms, with no or poor 64-bit performance. Note that the XXH3_family provides competitive speed for both 32-bit and 64-bit systems, and offers true 64/128 bit hash results.

See also

XXH64 family, XXH3_family : Other xxHash families

XXH32 implementation for implementation details

Macro Definition Documentation

XXH32_createState

XXH_PUBLIC_API XXH32_state_t * XXH32_createState

(

void

)

XXH_NAME2(XXH_NAMESPACE, XXH32_createState)

Allocates an XXH32_state_t.

Returns

An allocated pointer of XXH32_state_t on success.

NULL on failure.

Note

Must be freed with XXH32_freeState().

XXH32_state_t

struct XXH32_state_s XXH32_state_t   XXH_IPREF(XXH32_state_t)

The opaque state struct for the XXH32 streaming API.

See also

XXH32_state_s for details.

Function Documentation

XXH32()

XXH_PUBLIC_API XXH32_hash_t XXH32	(	const void *	input,
		size_t	length,
		XXH32_hash_t	seed
	)

Calculates the 32-bit hash of input using xxHash32.

Parameters

input	The block of data to be hashed, at least length bytes in size.
length	The length of input, in bytes.
seed	The 32-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 32-bit xxHash32 value.

See also

Single Shot Example for an example.

XXH32_canonicalFromHash()

XXH_PUBLIC_API void XXH32_canonicalFromHash	(	XXH32_canonical_t *	dst,
		XXH32_hash_t	hash
	)

Converts an XXH32_hash_t to a big endian XXH32_canonical_t.

Parameters

dst	The XXH32_canonical_t pointer to be stored to.
hash	The XXH32_hash_t to be converted.

Precondition

dst must not be NULL.

See also

Canonical Representation Example

XXH32_copyState()

XXH_PUBLIC_API void XXH32_copyState	(	XXH32_state_t *	dst_state,
		const XXH32_state_t *	src_state
	)

Copies one XXH32_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.

XXH32_digest()

XXH_PUBLIC_API XXH32_hash_t XXH32_digest

(

const XXH32_state_t *

statePtr

)

Returns the calculated hash value from an XXH32_state_t.

Parameters

statePtr

The state struct to calculate the hash from.

Precondition

statePtr must not be NULL.

Returns

The calculated 32-bit xxHash32 value from that state.

Note

Calling XXH32_digest() will not affect statePtr, so you can update, digest, and update again.

XXH32_freeState()

XXH_PUBLIC_API XXH_errorcode XXH32_freeState

(

XXH32_state_t *

statePtr

)

Frees an XXH32_state_t.

Parameters

statePtr

A pointer to an XXH32_state_t allocated with XXH32_createState().

Returns

XXH_OK.

Note

statePtr must be allocated with XXH32_createState().

XXH32_hashFromCanonical()

XXH_PUBLIC_API XXH32_hash_t XXH32_hashFromCanonical

(

const XXH32_canonical_t *

src

)

Converts an XXH32_canonical_t to a native XXH32_hash_t.

Parameters

src	The XXH32_canonical_t to convert.

Precondition

src must not be NULL.

Returns

The converted hash.

See also

Canonical Representation Example

XXH32_reset()

XXH_PUBLIC_API XXH_errorcode XXH32_reset	(	XXH32_state_t *	statePtr,
		XXH32_hash_t	seed
	)

Resets an XXH32_state_t to begin a new hash.

Parameters

statePtr	The state struct to reset.
seed	The 32-bit seed to alter the hash result predictably.

Precondition

statePtr must not be NULL.

Returns

XXH_OK on success.

XXH_ERROR on failure.

Note

This function resets and seeds a state. Call it before XXH32_update().

XXH32_update()

XXH_PUBLIC_API XXH_errorcode XXH32_update	(	XXH32_state_t *	statePtr,
		const void *	input,
		size_t	length
	)

Consumes a block of input to an XXH32_state_t.

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.

Note

Call this to incrementally consume blocks of data.