Libx xxHash

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    Data Structures

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

    Typedefs

    typedef struct XXH32_state_s XXH32_state_t
     The opaque state struct for the XXH32 streaming API.

    Functions

    XXH32_hash_t XXH32 (const void *input, size_t length, XXH32_hash_t seed)
     Calculates the 32-bit hash of input using xxHash32.
    XXH32_state_t * XXH32_createState (void)
     Allocates an XXH32_state_t.
    XXH_errorcode XXH32_freeState (XXH32_state_t *statePtr)
     Frees an XXH32_state_t.
    void XXH32_copyState (XXH32_state_t *dst_state, const XXH32_state_t *src_state)
     Copies one XXH32_state_t to another.
    XXH_errorcode XXH32_reset (XXH32_state_t *statePtr, XXH32_hash_t seed)
     Resets an XXH32_state_t to begin a new hash.
    XXH_errorcode XXH32_update (XXH32_state_t *statePtr, const void *input, size_t length)
     Consumes a block of input to an XXH32_state_t.
    XXH32_hash_t XXH32_digest (const XXH32_state_t *statePtr)
     Returns the calculated hash value from an XXH32_state_t.
    void XXH32_canonicalFromHash (XXH32_canonical_t *dst, XXH32_hash_t hash)
     Converts an XXH32_hash_t to a big endian XXH32_canonical_t.
    XXH32_hash_t XXH32_hashFromCanonical (const XXH32_canonical_t *src)
     Converts an XXH32_canonical_t to a native XXH32_hash_t.

    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

    Typedef Documentation

    ◆ XXH32_state_t

    typedef struct XXH32_state_s XXH32_state_t

    The opaque state struct for the XXH32 streaming API.

    See also
    XXH32_state_s for details.
    Streaming Example

    Function Documentation

    ◆ XXH32()

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

    Calculates the 32-bit hash of input using xxHash32.

    Parameters
    inputThe block of data to be hashed, at least length bytes in size.
    lengthThe length of input, in bytes.
    seedThe 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_createState()

    XXH32_state_t * XXH32_createState ( void )

    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().
    See also
    Streaming Example

    ◆ XXH32_freeState()

    XXH_errorcode XXH32_freeState ( XXH32_state_t * statePtr)

    Frees an XXH32_state_t.

    Parameters
    statePtrA pointer to an XXH32_state_t allocated with XXH32_createState().
    Returns
    XXH_OK.
    Note
    statePtr must be allocated with XXH32_createState().
    See also
    Streaming Example

    ◆ XXH32_copyState()

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

    Copies one XXH32_state_t to another.

    Parameters
    dst_stateThe state to copy to.
    src_stateThe state to copy from.
    Precondition
    dst_state and src_state must not be NULL and must not overlap.

    ◆ XXH32_reset()

    XXH_errorcode XXH32_reset ( XXH32_state_t * statePtr,
    XXH32_hash_t seed )

    Resets an XXH32_state_t to begin a new hash.

    Parameters
    statePtrThe state struct to reset.
    seedThe 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().
    See also
    Streaming Example

    ◆ XXH32_update()

    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
    statePtrThe state struct to update.
    inputThe block of data to be hashed, at least length bytes in size.
    lengthThe 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.
    See also
    Streaming Example

    ◆ XXH32_digest()

    XXH32_hash_t XXH32_digest ( const XXH32_state_t * statePtr)

    Returns the calculated hash value from an XXH32_state_t.

    Parameters
    statePtrThe 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.
    See also
    Streaming Example

    ◆ XXH32_canonicalFromHash()

    void XXH32_canonicalFromHash ( XXH32_canonical_t * dst,
    XXH32_hash_t hash )

    Converts an XXH32_hash_t to a big endian XXH32_canonical_t.

    Parameters
    dstThe XXH32_canonical_t pointer to be stored to.
    hashThe XXH32_hash_t to be converted.
    Precondition
    dst must not be NULL.
    See also
    Canonical Representation Example

    ◆ XXH32_hashFromCanonical()

    XXH32_hash_t XXH32_hashFromCanonical ( const XXH32_canonical_t * src)

    Converts an XXH32_canonical_t to a native XXH32_hash_t.

    Parameters
    srcThe XXH32_canonical_t to convert.
    Precondition
    src must not be NULL.
    Returns
    The converted hash.
    See also
    Canonical Representation Example