numam-dpdk/lib/hash/rte_jhash.h
Bruce Richardson 99a2dd955f lib: remove librte_ prefix from directory names
There is no reason for the DPDK libraries to all have 'librte_' prefix on
the directory names. This prefix makes the directory names longer and also
makes it awkward to add features referring to individual libraries in the
build - should the lib names be specified with or without the prefix.
Therefore, we can just remove the library prefix and use the library's
unique name as the directory name, i.e. 'eal' rather than 'librte_eal'

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
2021-04-21 14:04:09 +02:00

386 lines
9.2 KiB
C

/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2010-2015 Intel Corporation.
*/
#ifndef _RTE_JHASH_H
#define _RTE_JHASH_H
/**
* @file
*
* jhash functions.
*/
#ifdef __cplusplus
extern "C" {
#endif
#include <stdint.h>
#include <string.h>
#include <limits.h>
#include <rte_config.h>
#include <rte_log.h>
#include <rte_byteorder.h>
/* jhash.h: Jenkins hash support.
*
* Copyright (C) 2006 Bob Jenkins (bob_jenkins@burtleburtle.net)
*
* http://burtleburtle.net/bob/hash/
*
* These are the credits from Bob's sources:
*
* lookup3.c, by Bob Jenkins, May 2006, Public Domain.
*
* These are functions for producing 32-bit hashes for hash table lookup.
* hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
* are externally useful functions. Routines to test the hash are included
* if SELF_TEST is defined. You can use this free for any purpose. It's in
* the public domain. It has no warranty.
*
* $FreeBSD$
*/
#define rot(x, k) (((x) << (k)) | ((x) >> (32-(k))))
/** @internal Internal function. NOTE: Arguments are modified. */
#define __rte_jhash_mix(a, b, c) do { \
a -= c; a ^= rot(c, 4); c += b; \
b -= a; b ^= rot(a, 6); a += c; \
c -= b; c ^= rot(b, 8); b += a; \
a -= c; a ^= rot(c, 16); c += b; \
b -= a; b ^= rot(a, 19); a += c; \
c -= b; c ^= rot(b, 4); b += a; \
} while (0)
#define __rte_jhash_final(a, b, c) do { \
c ^= b; c -= rot(b, 14); \
a ^= c; a -= rot(c, 11); \
b ^= a; b -= rot(a, 25); \
c ^= b; c -= rot(b, 16); \
a ^= c; a -= rot(c, 4); \
b ^= a; b -= rot(a, 14); \
c ^= b; c -= rot(b, 24); \
} while (0)
/** The golden ratio: an arbitrary value. */
#define RTE_JHASH_GOLDEN_RATIO 0xdeadbeef
#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
#define BIT_SHIFT(x, y, k) (((x) >> (k)) | ((uint64_t)(y) << (32-(k))))
#else
#define BIT_SHIFT(x, y, k) (((uint64_t)(x) << (k)) | ((y) >> (32-(k))))
#endif
#define LOWER8b_MASK rte_le_to_cpu_32(0xff)
#define LOWER16b_MASK rte_le_to_cpu_32(0xffff)
#define LOWER24b_MASK rte_le_to_cpu_32(0xffffff)
static inline void
__rte_jhash_2hashes(const void *key, uint32_t length, uint32_t *pc,
uint32_t *pb, unsigned check_align)
{
uint32_t a, b, c;
/* Set up the internal state */
a = b = c = RTE_JHASH_GOLDEN_RATIO + ((uint32_t)length) + *pc;
c += *pb;
/*
* Check key alignment. For x86 architecture, first case is always optimal
* If check_align is not set, first case will be used
*/
#if defined(RTE_ARCH_X86)
const uint32_t *k = (const uint32_t *)key;
const uint32_t s = 0;
#else
const uint32_t *k = (uint32_t *)((uintptr_t)key & (uintptr_t)~3);
const uint32_t s = ((uintptr_t)key & 3) * CHAR_BIT;
#endif
if (!check_align || s == 0) {
while (length > 12) {
a += k[0];
b += k[1];
c += k[2];
__rte_jhash_mix(a, b, c);
k += 3;
length -= 12;
}
switch (length) {
case 12:
c += k[2]; b += k[1]; a += k[0]; break;
case 11:
c += k[2] & LOWER24b_MASK; b += k[1]; a += k[0]; break;
case 10:
c += k[2] & LOWER16b_MASK; b += k[1]; a += k[0]; break;
case 9:
c += k[2] & LOWER8b_MASK; b += k[1]; a += k[0]; break;
case 8:
b += k[1]; a += k[0]; break;
case 7:
b += k[1] & LOWER24b_MASK; a += k[0]; break;
case 6:
b += k[1] & LOWER16b_MASK; a += k[0]; break;
case 5:
b += k[1] & LOWER8b_MASK; a += k[0]; break;
case 4:
a += k[0]; break;
case 3:
a += k[0] & LOWER24b_MASK; break;
case 2:
a += k[0] & LOWER16b_MASK; break;
case 1:
a += k[0] & LOWER8b_MASK; break;
/* zero length strings require no mixing */
case 0:
*pc = c;
*pb = b;
return;
};
} else {
/* all but the last block: affect some 32 bits of (a, b, c) */
while (length > 12) {
a += BIT_SHIFT(k[0], k[1], s);
b += BIT_SHIFT(k[1], k[2], s);
c += BIT_SHIFT(k[2], k[3], s);
__rte_jhash_mix(a, b, c);
k += 3;
length -= 12;
}
/* last block: affect all 32 bits of (c) */
switch (length) {
case 12:
a += BIT_SHIFT(k[0], k[1], s);
b += BIT_SHIFT(k[1], k[2], s);
c += BIT_SHIFT(k[2], k[3], s);
break;
case 11:
a += BIT_SHIFT(k[0], k[1], s);
b += BIT_SHIFT(k[1], k[2], s);
c += BIT_SHIFT(k[2], k[3], s) & LOWER24b_MASK;
break;
case 10:
a += BIT_SHIFT(k[0], k[1], s);
b += BIT_SHIFT(k[1], k[2], s);
c += BIT_SHIFT(k[2], k[3], s) & LOWER16b_MASK;
break;
case 9:
a += BIT_SHIFT(k[0], k[1], s);
b += BIT_SHIFT(k[1], k[2], s);
c += BIT_SHIFT(k[2], k[3], s) & LOWER8b_MASK;
break;
case 8:
a += BIT_SHIFT(k[0], k[1], s);
b += BIT_SHIFT(k[1], k[2], s);
break;
case 7:
a += BIT_SHIFT(k[0], k[1], s);
b += BIT_SHIFT(k[1], k[2], s) & LOWER24b_MASK;
break;
case 6:
a += BIT_SHIFT(k[0], k[1], s);
b += BIT_SHIFT(k[1], k[2], s) & LOWER16b_MASK;
break;
case 5:
a += BIT_SHIFT(k[0], k[1], s);
b += BIT_SHIFT(k[1], k[2], s) & LOWER8b_MASK;
break;
case 4:
a += BIT_SHIFT(k[0], k[1], s);
break;
case 3:
a += BIT_SHIFT(k[0], k[1], s) & LOWER24b_MASK;
break;
case 2:
a += BIT_SHIFT(k[0], k[1], s) & LOWER16b_MASK;
break;
case 1:
a += BIT_SHIFT(k[0], k[1], s) & LOWER8b_MASK;
break;
/* zero length strings require no mixing */
case 0:
*pc = c;
*pb = b;
return;
}
}
__rte_jhash_final(a, b, c);
*pc = c;
*pb = b;
}
/**
* Same as rte_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 rte_jhash.
*
* @param key
* Key to calculate hash of.
* @param length
* Length of key in bytes.
* @param pc
* IN: seed OUT: primary hash value.
* @param pb
* IN: second seed OUT: secondary hash value.
*/
static inline void
rte_jhash_2hashes(const void *key, uint32_t length, uint32_t *pc, uint32_t *pb)
{
__rte_jhash_2hashes(key, length, pc, pb, 1);
}
/**
* Same as rte_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 rte_jhash_32b.
*
* @param k
* Key to calculate hash of.
* @param length
* Length of key in units of 4 bytes.
* @param pc
* IN: seed OUT: primary hash value.
* @param pb
* IN: second seed OUT: secondary hash value.
*/
static inline void
rte_jhash_32b_2hashes(const uint32_t *k, uint32_t length, uint32_t *pc, uint32_t *pb)
{
__rte_jhash_2hashes((const void *) k, (length << 2), pc, pb, 0);
}
/**
* 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.
*
* @param key
* Key to calculate hash of.
* @param length
* Length of key in bytes.
* @param initval
* Initialising value of hash.
* @return
* Calculated hash value.
*/
static inline uint32_t
rte_jhash(const void *key, uint32_t length, uint32_t initval)
{
uint32_t initval2 = 0;
rte_jhash_2hashes(key, length, &initval, &initval2);
return initval;
}
/**
* 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.
*
* @param k
* Key to calculate hash of.
* @param length
* Length of key in units of 4 bytes.
* @param initval
* Initialising value of hash.
* @return
* Calculated hash value.
*/
static inline uint32_t
rte_jhash_32b(const uint32_t *k, uint32_t length, uint32_t initval)
{
uint32_t initval2 = 0;
rte_jhash_32b_2hashes(k, length, &initval, &initval2);
return initval;
}
static inline uint32_t
__rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
{
a += RTE_JHASH_GOLDEN_RATIO + initval;
b += RTE_JHASH_GOLDEN_RATIO + initval;
c += RTE_JHASH_GOLDEN_RATIO + initval;
__rte_jhash_final(a, b, c);
return c;
}
/**
* A special ultra-optimized versions that knows it is hashing exactly
* 3 words.
*
* @param a
* First word to calculate hash of.
* @param b
* Second word to calculate hash of.
* @param c
* Third word to calculate hash of.
* @param initval
* Initialising value of hash.
* @return
* Calculated hash value.
*/
static inline uint32_t
rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
{
return __rte_jhash_3words(a + 12, b + 12, c + 12, initval);
}
/**
* A special ultra-optimized versions that knows it is hashing exactly
* 2 words.
*
* @param a
* First word to calculate hash of.
* @param b
* Second word to calculate hash of.
* @param initval
* Initialising value of hash.
* @return
* Calculated hash value.
*/
static inline uint32_t
rte_jhash_2words(uint32_t a, uint32_t b, uint32_t initval)
{
return __rte_jhash_3words(a + 8, b + 8, 8, initval);
}
/**
* A special ultra-optimized versions that knows it is hashing exactly
* 1 word.
*
* @param a
* Word to calculate hash of.
* @param initval
* Initialising value of hash.
* @return
* Calculated hash value.
*/
static inline uint32_t
rte_jhash_1word(uint32_t a, uint32_t initval)
{
return __rte_jhash_3words(a + 4, 4, 4, initval);
}
#ifdef __cplusplus
}
#endif
#endif /* _RTE_JHASH_H */