rte_jhash.h File Reference

#include <stdint.h>

Macros
#define	RTE_JHASH_GOLDEN_RATIO   0x9e3779b9

Functions
static uint32_t	rte_jhash (const void *key, uint32_t length, uint32_t initval)
static uint32_t	rte_jhash2 (const uint32_t *k, uint32_t length, uint32_t initval)
static uint32_t	rte_jhash_3words (uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
static uint32_t	rte_jhash_2words (uint32_t a, uint32_t b, uint32_t initval)
static uint32_t	rte_jhash_1word (uint32_t a, uint32_t initval)

Detailed Description

jhash functions.

Macro Definition Documentation

#define RTE_JHASH_GOLDEN_RATIO   0x9e3779b9

The golden ratio: an arbitrary value.

Function Documentation

static uint32_t rte_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.

Parameters

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

Returns

Calculated hash value.

static uint32_t rte_jhash2 ( 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.

static uint32_t rte_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 calcuate hash of.
initval	Initialising value of hash.

Returns

Calculated hash value.

static uint32_t rte_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 calcuate hash of.
b	Second word to calcuate hash of.
initval	Initialising value of hash.

Returns

Calculated hash value.

static uint32_t rte_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 calcuate hash of.
b	Second word to calcuate hash of.
c	Third word to calcuate hash of.
initval	Initialising value of hash.

Returns

Calculated hash value.