[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"

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

#define ROTL64(x, y) rotl64(x, y)
static __always_inline u64 getblock64(const u64 *p, int i)
{
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
	return p[i];
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
	return __builtin_bswap64(p[i]);
#else
#error "can't figure out byte order"
#endif
}

static __always_inline void putblock64(u64 *p, int i, u64 value)
{
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
	p[i] = value;
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
	p[i] = __builtin_bswap64(value);
#else
#error "can't figure out byte order"
#endif
}

/* 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;

	/* body */

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

	int i;

	for (i = 0; i < nblocks; i++) {
		u64 k1 = getblock64(blocks, i * 2 + 0);
		u64 k2 = getblock64(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;

	putblock64((u64 *)out, 0, h1);
	putblock64((u64 *)out, 1, h2);
}
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
	11	static inline u64 rotl64(u64 x, s8 r)
	12	{
	13	return (x << r) \| (x >> (64 - r));
	14	}
	15
	16	#define ROTL64(x, y) rotl64(x, y)
	17	static __always_inline u64 getblock64(const u64 *p, int i)
	18	{
	19	#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
	20	return p[i];
	21	#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
	22	return __builtin_bswap64(p[i]);
	23	#else
	24	#error "can't figure out byte order"
	25	#endif
	26	}
	27
	28	static __always_inline void putblock64(u64 *p, int i, u64 value)
	29	{
	30	#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
	31	p[i] = value;
	32	#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
	33	p[i] = __builtin_bswap64(value);
	34	#else
	35	#error "can't figure out byte order"
	36	#endif
	37	}
	38
	39	/* Finalization mix - force all bits of a hash block to avalanche */
	40
	41	static __always_inline u64 fmix64(u64 k)
	42	{
	43	k ^= k >> 33;
	44	k *= 0xff51afd7ed558ccdLLU;
	45	k ^= k >> 33;
	46	k *= 0xc4ceb9fe1a85ec53LLU;
	47	k ^= k >> 33;
	48
	49	return k;
	50	}
	51
	52	void murmurhash3_128(const void key, const int len, const u32 seed, void out)
	53	{
	54	const u8 *data = key;
	55	const int nblocks = len / 16;
	56
	57	u64 h1 = seed;
	58	u64 h2 = seed;
	59
	60	const u64 c1 = 0x87c37b91114253d5LLU;
	61	const u64 c2 = 0x4cf5ad432745937fLLU;
	62
	63	/* body */
	64
65	const u64 blocks = (const u64 )(data);
66
67	int i;
68
69	for (i = 0; i < nblocks; i++) {
70	u64 k1 = getblock64(blocks, i * 2 + 0);
71	u64 k2 = getblock64(blocks, i * 2 + 1);
72
73	k1 *= c1;
74	k1 = ROTL64(k1, 31);
75	k1 *= c2;
76	h1 ^= k1;
77
78	h1 = ROTL64(h1, 27);
79	h1 += h2;
80	h1 = h1 * 5 + 0x52dce729;
81
82	k2 *= c2;
83	k2 = ROTL64(k2, 33);
84	k2 *= c1;
85	h2 ^= k2;
86
87	h2 = ROTL64(h2, 31);
88	h2 += h1;
89	h2 = h2 * 5 + 0x38495ab5;
90	}
91
92	/* tail */
93
94	{
95	const u8 tail = (const u8 )(data + nblocks * 16);
96
97	u64 k1 = 0;
98	u64 k2 = 0;
99
100	switch (len & 15) {
101	case 15:
102	k2 ^= ((u64)tail[14]) << 48;
103	fallthrough;
104	case 14:
105	k2 ^= ((u64)tail[13]) << 40;
106	fallthrough;
107	case 13:
108	k2 ^= ((u64)tail[12]) << 32;
109	fallthrough;
110	case 12:
111	k2 ^= ((u64)tail[11]) << 24;
112	fallthrough;
113	case 11:
114	k2 ^= ((u64)tail[10]) << 16;
115	fallthrough;
116	case 10:
117	k2 ^= ((u64)tail[9]) << 8;
118	fallthrough;
119	case 9:
120	k2 ^= ((u64)tail[8]) << 0;
121	k2 *= c2;
122	k2 = ROTL64(k2, 33);
123	k2 *= c1;
124	h2 ^= k2;
125	fallthrough;
126
127	case 8:
128	k1 ^= ((u64)tail[7]) << 56;
129	fallthrough;
130	case 7:
131	k1 ^= ((u64)tail[6]) << 48;
132	fallthrough;
133	case 6:
134	k1 ^= ((u64)tail[5]) << 40;
135	fallthrough;
136	case 5:
137	k1 ^= ((u64)tail[4]) << 32;
138	fallthrough;
139	case 4:
140	k1 ^= ((u64)tail[3]) << 24;
141	fallthrough;
142	case 3:
143	k1 ^= ((u64)tail[2]) << 16;
144	fallthrough;
145	case 2:
146	k1 ^= ((u64)tail[1]) << 8;
147	fallthrough;
148	case 1:
149	k1 ^= ((u64)tail[0]) << 0;
150	k1 *= c1;
151	k1 = ROTL64(k1, 31);
152	k1 *= c2;
153	h1 ^= k1;
154	break;
155	default:
156	break;
157	};
158	}
159	/* finalization */
160
161	h1 ^= len;
162	h2 ^= len;
163
164	h1 += h2;
165	h2 += h1;
166
167	h1 = fmix64(h1);
168	h2 = fmix64(h2);
169
170	h1 += h2;
171	h2 += h1;
172
173	putblock64((u64 *)out, 0, h1);
174	putblock64((u64 *)out, 1, h2);
175	}