[linux-block.git] / drivers / md / dm-vdo / murmurhash3.c

// SPDX-License-Identifier: LGPL-2.1+
/*
 * MurmurHash3 was written by Austin Appleby, and is placed in the public
 * domain. The author hereby disclaims copyright to this source code.
 *
 * Adapted by John Wiele (jwiele@redhat.com).
 */

#include "murmurhash3.h"

#include <asm/unaligned.h>

static inline u64 rotl64(u64 x, s8 r)
{
	return (x << r) | (x >> (64 - r));
}

#define ROTL64(x, y) rotl64(x, y)

/* Finalization mix - force all bits of a hash block to avalanche */

static __always_inline u64 fmix64(u64 k)
{
	k ^= k >> 33;
	k *= 0xff51afd7ed558ccdLLU;
	k ^= k >> 33;
	k *= 0xc4ceb9fe1a85ec53LLU;
	k ^= k >> 33;

	return k;
}

void murmurhash3_128(const void *key, const int len, const u32 seed, void *out)
{
	const u8 *data = key;
	const int nblocks = len / 16;

	u64 h1 = seed;
	u64 h2 = seed;

	const u64 c1 = 0x87c37b91114253d5LLU;
	const u64 c2 = 0x4cf5ad432745937fLLU;

	u64 *hash_out = out;

	/* body */

	const u64 *blocks = (const u64 *)(data);

	int i;

	for (i = 0; i < nblocks; i++) {
		u64 k1 = get_unaligned_le64(&blocks[i * 2]);
		u64 k2 = get_unaligned_le64(&blocks[i * 2 + 1]);

		k1 *= c1;
		k1 = ROTL64(k1, 31);
		k1 *= c2;
		h1 ^= k1;

		h1 = ROTL64(h1, 27);
		h1 += h2;
		h1 = h1 * 5 + 0x52dce729;

		k2 *= c2;
		k2 = ROTL64(k2, 33);
		k2 *= c1;
		h2 ^= k2;

		h2 = ROTL64(h2, 31);
		h2 += h1;
		h2 = h2 * 5 + 0x38495ab5;
	}

	/* tail */

	{
		const u8 *tail = (const u8 *)(data + nblocks * 16);

		u64 k1 = 0;
		u64 k2 = 0;

		switch (len & 15) {
		case 15:
			k2 ^= ((u64)tail[14]) << 48;
			fallthrough;
		case 14:
			k2 ^= ((u64)tail[13]) << 40;
			fallthrough;
		case 13:
			k2 ^= ((u64)tail[12]) << 32;
			fallthrough;
		case 12:
			k2 ^= ((u64)tail[11]) << 24;
			fallthrough;
		case 11:
			k2 ^= ((u64)tail[10]) << 16;
			fallthrough;
		case 10:
			k2 ^= ((u64)tail[9]) << 8;
			fallthrough;
		case 9:
			k2 ^= ((u64)tail[8]) << 0;
			k2 *= c2;
			k2 = ROTL64(k2, 33);
			k2 *= c1;
			h2 ^= k2;
			fallthrough;

		case 8:
			k1 ^= ((u64)tail[7]) << 56;
			fallthrough;
		case 7:
			k1 ^= ((u64)tail[6]) << 48;
			fallthrough;
		case 6:
			k1 ^= ((u64)tail[5]) << 40;
			fallthrough;
		case 5:
			k1 ^= ((u64)tail[4]) << 32;
			fallthrough;
		case 4:
			k1 ^= ((u64)tail[3]) << 24;
			fallthrough;
		case 3:
			k1 ^= ((u64)tail[2]) << 16;
			fallthrough;
		case 2:
			k1 ^= ((u64)tail[1]) << 8;
			fallthrough;
		case 1:
			k1 ^= ((u64)tail[0]) << 0;
			k1 *= c1;
			k1 = ROTL64(k1, 31);
			k1 *= c2;
			h1 ^= k1;
			break;
		default:
			break;
		}
	}
	/* finalization */

	h1 ^= len;
	h2 ^= len;

	h1 += h2;
	h2 += h1;

	h1 = fmix64(h1);
	h2 = fmix64(h2);

	h1 += h2;
	h2 += h1;

	put_unaligned_le64(h1, &hash_out[0]);
	put_unaligned_le64(h2, &hash_out[1]);
}
Commit	Line	Data
a3957b1f MS	1	// SPDX-License-Identifier: LGPL-2.1+
	2	/*
	3	* MurmurHash3 was written by Austin Appleby, and is placed in the public
	4	* domain. The author hereby disclaims copyright to this source code.
	5	*
	6	* Adapted by John Wiele (jwiele@redhat.com).
	7	*/
	8
	9	#include "murmurhash3.h"
	10
d7e12014 KR	11	#include <asm/unaligned.h>
d7e12014 KR	12
a3957b1f MS	13	static inline u64 rotl64(u64 x, s8 r)
	14	{
	15	return (x << r) \| (x >> (64 - r));
	16	}
	17
	18	#define ROTL64(x, y) rotl64(x, y)
a3957b1f MS	19
	20	/* Finalization mix - force all bits of a hash block to avalanche */
	21
	22	static __always_inline u64 fmix64(u64 k)
	23	{
	24	k ^= k >> 33;
	25	k *= 0xff51afd7ed558ccdLLU;
	26	k ^= k >> 33;
	27	k *= 0xc4ceb9fe1a85ec53LLU;
	28	k ^= k >> 33;
	29
	30	return k;
	31	}
	32
	33	void murmurhash3_128(const void key, const int len, const u32 seed, void out)
	34	{
	35	const u8 *data = key;
	36	const int nblocks = len / 16;
	37
	38	u64 h1 = seed;
	39	u64 h2 = seed;
	40
	41	const u64 c1 = 0x87c37b91114253d5LLU;
	42	const u64 c2 = 0x4cf5ad432745937fLLU;
	43
d7e12014 KR	44	u64 *hash_out = out;
d7e12014 KR	45
a3957b1f MS	46	/* body */
	47
	48	const u64 blocks = (const u64 )(data);
	49
	50	int i;
	51
	52	for (i = 0; i < nblocks; i++) {
d7e12014 KR	53	u64 k1 = get_unaligned_le64(&blocks[i * 2]);
d7e12014 KR	54	u64 k2 = get_unaligned_le64(&blocks[i * 2 + 1]);
a3957b1f MS	55
	56	k1 *= c1;
	57	k1 = ROTL64(k1, 31);
	58	k1 *= c2;
	59	h1 ^= k1;
	60
	61	h1 = ROTL64(h1, 27);
	62	h1 += h2;
	63	h1 = h1 * 5 + 0x52dce729;
	64
	65	k2 *= c2;
	66	k2 = ROTL64(k2, 33);
	67	k2 *= c1;
	68	h2 ^= k2;
	69
	70	h2 = ROTL64(h2, 31);
	71	h2 += h1;
	72	h2 = h2 * 5 + 0x38495ab5;
	73	}
	74
	75	/* tail */
	76
	77	{
	78	const u8 tail = (const u8 )(data + nblocks * 16);
	79
	80	u64 k1 = 0;
	81	u64 k2 = 0;
	82
	83	switch (len & 15) {
	84	case 15:
	85	k2 ^= ((u64)tail[14]) << 48;
	86	fallthrough;
	87	case 14:
	88	k2 ^= ((u64)tail[13]) << 40;
	89	fallthrough;
	90	case 13:
	91	k2 ^= ((u64)tail[12]) << 32;
	92	fallthrough;
	93	case 12:
	94	k2 ^= ((u64)tail[11]) << 24;
	95	fallthrough;
	96	case 11:
	97	k2 ^= ((u64)tail[10]) << 16;
	98	fallthrough;
	99	case 10:
	100	k2 ^= ((u64)tail[9]) << 8;
	101	fallthrough;
	102	case 9:
	103	k2 ^= ((u64)tail[8]) << 0;
	104	k2 *= c2;
	105	k2 = ROTL64(k2, 33);
	106	k2 *= c1;
	107	h2 ^= k2;
	108	fallthrough;
	109
	110	case 8:
	111	k1 ^= ((u64)tail[7]) << 56;
	112	fallthrough;
	113	case 7:
	114	k1 ^= ((u64)tail[6]) << 48;
	115	fallthrough;
	116	case 6:
	117	k1 ^= ((u64)tail[5]) << 40;
	118	fallthrough;
119	case 5:
120	k1 ^= ((u64)tail[4]) << 32;
121	fallthrough;
122	case 4:
123	k1 ^= ((u64)tail[3]) << 24;
124	fallthrough;
125	case 3:
126	k1 ^= ((u64)tail[2]) << 16;
127	fallthrough;
128	case 2:
129	k1 ^= ((u64)tail[1]) << 8;
130	fallthrough;
131	case 1:
132	k1 ^= ((u64)tail[0]) << 0;
133	k1 *= c1;
134	k1 = ROTL64(k1, 31);
135	k1 *= c2;
136	h1 ^= k1;
137	break;
138	default:
139	break;
f141dde5	140	}
a3957b1f MS	141	}
	142	/* finalization */
	143
	144	h1 ^= len;
	145	h2 ^= len;
	146
	147	h1 += h2;
	148	h2 += h1;
	149
	150	h1 = fmix64(h1);
	151	h2 = fmix64(h2);
	152
	153	h1 += h2;
	154	h2 += h1;
	155
d7e12014 KR	156	put_unaligned_le64(h1, &hash_out[0]);
d7e12014 KR	157	put_unaligned_le64(h2, &hash_out[1]);
a3957b1f	158	}