cne_jhash.h File Reference

#include <stdint.h>
#include <string.h>
#include <limits.h>
#include <endian.h>
#include <cne_log.h>

Go to the source code of this file.

Macros
#define	CNE_JHASH_GOLDEN_RATIO   0xdeadbeef

Functions
static void	cne_jhash_2hashes (const void *key, uint32_t length, uint32_t *pc, uint32_t *pb)
static void	cne_jhash_32b_2hashes (const uint32_t *k, uint32_t length, uint32_t *pc, uint32_t *pb)
static uint32_t	cne_jhash (const void *key, uint32_t length, uint32_t initval)
static uint32_t	cne_jhash_32b (const uint32_t *k, uint32_t length, uint32_t initval)
static uint32_t	cne_jhash_3words (uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
static uint32_t	cne_jhash_2words (uint32_t a, uint32_t b, uint32_t initval)
static uint32_t	cne_jhash_1word (uint32_t a, uint32_t initval)

Detailed Description

jhash functions.

Definition in file cne_jhash.h.

Macro Definition Documentation

CNE_JHASH_GOLDEN_RATIO

#define CNE_JHASH_GOLDEN_RATIO   0xdeadbeef

The golden ratio: an arbitrary value.

Definition at line 69 of file cne_jhash.h.

Function Documentation

cne_jhash_2hashes()

static void cne_jhash_2hashes ( const void *  key, uint32_t  length, uint32_t *  pc, uint32_t *  pb  )

inlinestatic

Same as cne_jhash, but takes two seeds and return two uint32_ts. pc and pb must be non-null, and *pc and *pb must both be initialized with seeds. If you pass in (*pb)=0, the output (*pc) will be the same as the return value from cne_jhash.

Parameters

key	Key to calculate hash of.
length	Length of key in bytes.
pc	IN: seed OUT: primary hash value.
pb	IN: second seed OUT: secondary hash value.

Definition at line 233 of file cne_jhash.h.

cne_jhash_32b_2hashes()

static void cne_jhash_32b_2hashes ( const uint32_t *  k, uint32_t  length, uint32_t *  pc, uint32_t *  pb  )

inlinestatic

Same as cne_jhash_32b, but takes two seeds and return two uint32_ts. pc and pb must be non-null, and *pc and *pb must both be initialized with seeds. If you pass in (*pb)=0, the output (*pc) will be the same as the return value from cne_jhash_32b.

Parameters

k	Key to calculate hash of.
length	Length of key in units of 4 bytes.
pc	IN: seed OUT: primary hash value.
pb	IN: second seed OUT: secondary hash value.

Definition at line 254 of file cne_jhash.h.

cne_jhash()

static uint32_t cne_jhash ( const void *  key, uint32_t  length, uint32_t  initval  )

inlinestatic

The most generic version, hashes an arbitrary sequence of bytes. No alignment or length assumptions are made about the input key. For keys not aligned to four byte boundaries or a multiple of four bytes in length, the memory region just after may be read (but not used in the computation). This may cross a page boundary.

Parameters

key	Key to calculate hash of.
length	Length of key in bytes.
initval	Initialising value of hash.

Returns

Calculated hash value.

Definition at line 277 of file cne_jhash.h.

cne_jhash_32b()

static uint32_t cne_jhash_32b ( const uint32_t *  k, uint32_t  length, uint32_t  initval  )

inlinestatic

A special optimized version that handles 1 or more of uint32_ts. The length parameter here is the number of uint32_ts in the key.

Parameters

k	Key to calculate hash of.
length	Length of key in units of 4 bytes.
initval	Initialising value of hash.

Returns

Calculated hash value.

Definition at line 300 of file cne_jhash.h.

cne_jhash_3words()

static uint32_t cne_jhash_3words ( uint32_t  a, uint32_t  b, uint32_t  c, uint32_t  initval  )

inlinestatic

A special ultra-optimized versions that knows it is hashing exactly 3 words.

Parameters

a	First word to calculate hash of.
b	Second word to calculate hash of.
c	Third word to calculate hash of.
initval	Initialising value of hash.

Returns

Calculated hash value.

Definition at line 337 of file cne_jhash.h.

cne_jhash_2words()

static uint32_t cne_jhash_2words ( uint32_t  a, uint32_t  b, uint32_t  initval  )

inlinestatic

A special ultra-optimized versions that knows it is hashing exactly 2 words.

Parameters

a	First word to calculate hash of.
b	Second word to calculate hash of.
initval	Initialising value of hash.

Returns

Calculated hash value.

Definition at line 356 of file cne_jhash.h.

cne_jhash_1word()

static uint32_t cne_jhash_1word ( uint32_t  a, uint32_t  initval  )

inlinestatic

A special ultra-optimized versions that knows it is hashing exactly 1 word.

Parameters

a	Word to calculate hash of.
initval	Initialising value of hash.

Returns

Calculated hash value.

Definition at line 373 of file cne_jhash.h.