ref: 849389558d7c989902662f32ba956e34ac4e21c5
dir: /3rd/spooky.c/
//
// SpookyHash - 128-bit noncryptographic hash function
//
// Written in 2012 by Bob Jenkins
//
// Converted to C in 2015 by Joergen Ibsen
//
// To the extent possible under law, the author(s) have dedicated all
// copyright and related and neighboring rights to this software to the
// public domain worldwide. This software is distributed without any
// warranty. <http://creativecommons.org/publicdomain/zero/1.0/>
//
// Original comment from SpookyV2.cpp by Bob Jenkins:
//
// Spooky Hash
// A 128-bit noncryptographic hash, for checksums and table lookup
// By Bob Jenkins. Public domain.
// Oct 31 2010: published framework, disclaimer ShortHash isn't right
// Nov 7 2010: disabled ShortHash
// Oct 31 2011: replace End, ShortMix, ShortEnd, enable ShortHash again
// April 10 2012: buffer overflow on platforms without unaligned reads
// July 12 2012: was passing out variables in final to in/out in short
// July 30 2012: I reintroduced the buffer overflow
// August 5 2012: SpookyV2: d = should be d += in short hash, and remove extra mix from long hash
#include "platform.h"
#include "spooky.h"
#define ALLOW_UNALIGNED_READS 0
//
// SC_CONST: a constant which:
// - is not zero
// - is odd
// - is a not-very-regular mix of 1's and 0's
// - does not need any other special mathematical properties
//
#define SC_CONST 0xDEADBEEFDEADBEEFULL
#define ROTL64(x, k) (((x) << (k)) | ((x) >> (64 - (k))))
#ifdef _MSC_VER
# define restrict __restrict
# define inline __forceinline
#endif
static bool
spooky_is_aligned(const void *p, size_t size)
{
return (uintptr_t) p % size == 0;
}
static bool
spooky_is_little_endian(void)
{
const union {
uint32_t i;
uint8_t c[sizeof(uint32_t)];
} x = { 1 };
return x.c[0];
}
//
// Read uint64_t in little-endian order.
//
static inline uint64_t
spooky_read_le64(const uint64_t *s)
{
if (spooky_is_little_endian()) {
uint64_t v;
memcpy(&v, s, sizeof(v));
return v;
}
else {
const uint8_t *p = (const uint8_t *) s;
return (uint64_t) p[0]
| ((uint64_t) p[1] << 8)
| ((uint64_t) p[2] << 16)
| ((uint64_t) p[3] << 24)
| ((uint64_t) p[4] << 32)
| ((uint64_t) p[5] << 40)
| ((uint64_t) p[6] << 48)
| ((uint64_t) p[7] << 56);
}
}
//
// This is used if the input is 96 bytes long or longer.
//
// The internal state is fully overwritten every 96 bytes.
// Every input bit appears to cause at least 128 bits of entropy
// before 96 other bytes are combined, when run forward or backward
// For every input bit,
// Two inputs differing in just that input bit
// Where "differ" means xor or subtraction
// And the base value is random
// When run forward or backwards one Mix
// I tried 3 pairs of each; they all differed by at least 212 bits.
//
static inline void
spooky_mix(const uint64_t *restrict data, uint64_t *restrict s)
{
s[0] += spooky_read_le64(&data[0]); s[2] ^= s[10];
s[11] ^= s[0]; s[0] = ROTL64(s[0], 11); s[11] += s[1];
s[1] += spooky_read_le64(&data[1]); s[3] ^= s[11];
s[0] ^= s[1]; s[1] = ROTL64(s[1], 32); s[0] += s[2];
s[2] += spooky_read_le64(&data[2]); s[4] ^= s[0];
s[1] ^= s[2]; s[2] = ROTL64(s[2], 43); s[1] += s[3];
s[3] += spooky_read_le64(&data[3]); s[5] ^= s[1];
s[2] ^= s[3]; s[3] = ROTL64(s[3], 31); s[2] += s[4];
s[4] += spooky_read_le64(&data[4]); s[6] ^= s[2];
s[3] ^= s[4]; s[4] = ROTL64(s[4], 17); s[3] += s[5];
s[5] += spooky_read_le64(&data[5]); s[7] ^= s[3];
s[4] ^= s[5]; s[5] = ROTL64(s[5], 28); s[4] += s[6];
s[6] += spooky_read_le64(&data[6]); s[8] ^= s[4];
s[5] ^= s[6]; s[6] = ROTL64(s[6], 39); s[5] += s[7];
s[7] += spooky_read_le64(&data[7]); s[9] ^= s[5];
s[6] ^= s[7]; s[7] = ROTL64(s[7], 57); s[6] += s[8];
s[8] += spooky_read_le64(&data[8]); s[10] ^= s[6];
s[7] ^= s[8]; s[8] = ROTL64(s[8], 55); s[7] += s[9];
s[9] += spooky_read_le64(&data[9]); s[11] ^= s[7];
s[8] ^= s[9]; s[9] = ROTL64(s[9], 54); s[8] += s[10];
s[10] += spooky_read_le64(&data[10]); s[0] ^= s[8];
s[9] ^= s[10]; s[10] = ROTL64(s[10], 22); s[9] += s[11];
s[11] += spooky_read_le64(&data[11]); s[1] ^= s[9];
s[10] ^= s[11]; s[11] = ROTL64(s[11], 46); s[10] += s[0];
}
//
// Mix all 12 inputs together so that h0, h1 are a hash of them all.
//
// For two inputs differing in just the input bits
// Where "differ" means xor or subtraction
// And the base value is random, or a counting value starting at that bit
// The final result will have each bit of h0, h1 flip
// For every input bit,
// with probability 50 +- .3%
// For every pair of input bits,
// with probability 50 +- 3%
//
// This does not rely on the last Mix() call having already mixed some.
// Two iterations was almost good enough for a 64-bit result, but a
// 128-bit result is reported, so End() does three iterations.
//
static inline void
spooky_end_partial(uint64_t *h)
{
h[11] += h[1]; h[2] ^= h[11]; h[1] = ROTL64(h[1], 44);
h[0] += h[2]; h[3] ^= h[0]; h[2] = ROTL64(h[2], 15);
h[1] += h[3]; h[4] ^= h[1]; h[3] = ROTL64(h[3], 34);
h[2] += h[4]; h[5] ^= h[2]; h[4] = ROTL64(h[4], 21);
h[3] += h[5]; h[6] ^= h[3]; h[5] = ROTL64(h[5], 38);
h[4] += h[6]; h[7] ^= h[4]; h[6] = ROTL64(h[6], 33);
h[5] += h[7]; h[8] ^= h[5]; h[7] = ROTL64(h[7], 10);
h[6] += h[8]; h[9] ^= h[6]; h[8] = ROTL64(h[8], 13);
h[7] += h[9]; h[10] ^= h[7]; h[9] = ROTL64(h[9], 38);
h[8] += h[10]; h[11] ^= h[8]; h[10] = ROTL64(h[10], 53);
h[9] += h[11]; h[0] ^= h[9]; h[11] = ROTL64(h[11], 42);
h[10] += h[0]; h[1] ^= h[10]; h[0] = ROTL64(h[0], 54);
}
static inline void
spooky_end(const uint64_t *restrict data, uint64_t *restrict h)
{
h[0] += spooky_read_le64(&data[0]);
h[1] += spooky_read_le64(&data[1]);
h[2] += spooky_read_le64(&data[2]);
h[3] += spooky_read_le64(&data[3]);
h[4] += spooky_read_le64(&data[4]);
h[5] += spooky_read_le64(&data[5]);
h[6] += spooky_read_le64(&data[6]);
h[7] += spooky_read_le64(&data[7]);
h[8] += spooky_read_le64(&data[8]);
h[9] += spooky_read_le64(&data[9]);
h[10] += spooky_read_le64(&data[10]);
h[11] += spooky_read_le64(&data[11]);
spooky_end_partial(h);
spooky_end_partial(h);
spooky_end_partial(h);
}
//
// The goal is for each bit of the input to expand into 128 bits of
// apparent entropy before it is fully overwritten.
// n trials both set and cleared at least m bits of h0 h1 h2 h3
// n: 2 m: 29
// n: 3 m: 46
// n: 4 m: 57
// n: 5 m: 107
// n: 6 m: 146
// n: 7 m: 152
// when run forwards or backwards
// for all 1-bit and 2-bit diffs
// with diffs defined by either xor or subtraction
// with a base of all zeros plus a counter, or plus another bit, or random
//
static inline void
spooky_short_mix(uint64_t *h)
{
h[2] = ROTL64(h[2], 50); h[2] += h[3]; h[0] ^= h[2];
h[3] = ROTL64(h[3], 52); h[3] += h[0]; h[1] ^= h[3];
h[0] = ROTL64(h[0], 30); h[0] += h[1]; h[2] ^= h[0];
h[1] = ROTL64(h[1], 41); h[1] += h[2]; h[3] ^= h[1];
h[2] = ROTL64(h[2], 54); h[2] += h[3]; h[0] ^= h[2];
h[3] = ROTL64(h[3], 48); h[3] += h[0]; h[1] ^= h[3];
h[0] = ROTL64(h[0], 38); h[0] += h[1]; h[2] ^= h[0];
h[1] = ROTL64(h[1], 37); h[1] += h[2]; h[3] ^= h[1];
h[2] = ROTL64(h[2], 62); h[2] += h[3]; h[0] ^= h[2];
h[3] = ROTL64(h[3], 34); h[3] += h[0]; h[1] ^= h[3];
h[0] = ROTL64(h[0], 5); h[0] += h[1]; h[2] ^= h[0];
h[1] = ROTL64(h[1], 36); h[1] += h[2]; h[3] ^= h[1];
}
//
// Mix all 4 inputs together so that h0, h1 are a hash of them all.
//
// For two inputs differing in just the input bits
// Where "differ" means xor or subtraction
// And the base value is random, or a counting value starting at that bit
// The final result will have each bit of h0, h1 flip
// For every input bit,
// with probability 50 +- .3% (it is probably better than that)
// For every pair of input bits,
// with probability 50 +- .75% (the worst case is approximately that)
//
static inline void
spooky_short_end(uint64_t *h)
{
h[3] ^= h[2]; h[2] = ROTL64(h[2], 15); h[3] += h[2];
h[0] ^= h[3]; h[3] = ROTL64(h[3], 52); h[0] += h[3];
h[1] ^= h[0]; h[0] = ROTL64(h[0], 26); h[1] += h[0];
h[2] ^= h[1]; h[1] = ROTL64(h[1], 51); h[2] += h[1];
h[3] ^= h[2]; h[2] = ROTL64(h[2], 28); h[3] += h[2];
h[0] ^= h[3]; h[3] = ROTL64(h[3], 9); h[0] += h[3];
h[1] ^= h[0]; h[0] = ROTL64(h[0], 47); h[1] += h[0];
h[2] ^= h[1]; h[1] = ROTL64(h[1], 54); h[2] += h[1];
h[3] ^= h[2]; h[2] = ROTL64(h[2], 32); h[3] += h[2];
h[0] ^= h[3]; h[3] = ROTL64(h[3], 25); h[0] += h[3];
h[1] ^= h[0]; h[0] = ROTL64(h[0], 63); h[1] += h[0];
}
//
// short hash ... it could be used on any message,
// but it's used by Spooky just for short messages.
//
static void
spooky_short(const void *restrict message, size_t length,
uint64_t *restrict hash1, uint64_t *restrict hash2)
{
uint64_t buf[2 * SC_NUMVARS];
union {
const uint8_t *p8;
uint64_t *p64;
} u;
u.p8 = (const uint8_t *) message;
if (ALLOW_UNALIGNED_READS == 0 && !spooky_is_aligned(u.p8, 8)) {
memcpy(buf, message, length);
u.p64 = buf;
}
size_t left = length % 32;
uint64_t h[4];
h[0] = *hash1;
h[1] = *hash2;
h[2] = SC_CONST;
h[3] = SC_CONST;
if (length > 15) {
const uint64_t *end = u.p64 + (length / 32) * 4;
// handle all complete sets of 32 bytes
for (; u.p64 < end; u.p64 += 4) {
h[2] += spooky_read_le64(&u.p64[0]);
h[3] += spooky_read_le64(&u.p64[1]);
spooky_short_mix(h);
h[0] += spooky_read_le64(&u.p64[2]);
h[1] += spooky_read_le64(&u.p64[3]);
}
//Handle the case of 16+ remaining bytes.
if (left >= 16) {
h[2] += spooky_read_le64(&u.p64[0]);
h[3] += spooky_read_le64(&u.p64[1]);
spooky_short_mix(h);
u.p64 += 2;
left -= 16;
}
}
// Handle the last 0..15 bytes, and its length
h[3] += ((uint64_t) length) << 56;
switch (left) {
case 15:
h[3] += ((uint64_t) u.p8[14]) << 48; // fallthrough
case 14:
h[3] += ((uint64_t) u.p8[13]) << 40; // fallthrough
case 13:
h[3] += ((uint64_t) u.p8[12]) << 32; // fallthrough
case 12:
h[3] += ((uint64_t) u.p8[11]) << 24; // fallthrough
case 11:
h[3] += ((uint64_t) u.p8[10]) << 16; // fallthrough
case 10:
h[3] += ((uint64_t) u.p8[9]) << 8; // fallthrough
case 9:
h[3] += (uint64_t) u.p8[8]; // fallthrough
case 8:
h[2] += spooky_read_le64(&u.p64[0]);
break;
case 7:
h[2] += ((uint64_t) u.p8[6]) << 48; // fallthrough
case 6:
h[2] += ((uint64_t) u.p8[5]) << 40; // fallthrough
case 5:
h[2] += ((uint64_t) u.p8[4]) << 32; // fallthrough
case 4:
h[2] += ((uint64_t) u.p8[3]) << 24; // fallthrough
case 3:
h[2] += ((uint64_t) u.p8[2]) << 16; // fallthrough
case 2:
h[2] += ((uint64_t) u.p8[1]) << 8; // fallthrough
case 1:
h[2] += (uint64_t) u.p8[0];
break;
case 0:
h[2] += SC_CONST;
h[3] += SC_CONST;
}
spooky_short_end(h);
*hash1 = h[0];
*hash2 = h[1];
}
uint64_t
spooky_hash64(const void *message, size_t length, uint64_t seed)
{
uint64_t hash1 = seed;
spooky_hash128(message, length, &hash1, &seed);
return hash1;
}
uint32_t
spooky_hash32(const void *message, size_t length, uint32_t seed)
{
uint64_t hash1 = seed, hash2 = seed;
spooky_hash128(message, length, &hash1, &hash2);
return (uint32_t) hash1;
}
// do the whole hash in one call
void
spooky_hash128(const void *restrict message, size_t length,
uint64_t *restrict hash1, uint64_t *restrict hash2)
{
if (length < SC_BUFSIZE) {
spooky_short(message, length, hash1, hash2);
return;
}
uint64_t h[SC_NUMVARS];
uint64_t buf[SC_NUMVARS];
uint64_t *end;
union {
const uint8_t *p8;
uint64_t *p64;
} u;
size_t left;
h[0] = *hash1;
h[1] = *hash2;
h[2] = SC_CONST;
h[3] = *hash1;
h[4] = *hash2;
h[5] = SC_CONST;
h[6] = *hash1;
h[7] = *hash2;
h[8] = SC_CONST;
h[9] = *hash1;
h[10] = *hash2;
h[11] = SC_CONST;
u.p8 = (const uint8_t *) message;
end = u.p64 + (length / SC_BLOCKSIZE) * SC_NUMVARS;
// handle all whole SC_BLOCKSIZE blocks of bytes
if (ALLOW_UNALIGNED_READS || spooky_is_aligned(u.p8, 8)) {
do {
spooky_mix(u.p64, h);
u.p64 += SC_NUMVARS;
} while (u.p64 < end);
}
else {
do {
memcpy(buf, u.p64, SC_BLOCKSIZE);
spooky_mix(buf, h);
u.p64 += SC_NUMVARS;
} while (u.p64 < end);
}
// handle the last partial block of SC_BLOCKSIZE bytes
left = length - ((const uint8_t *) end - (const uint8_t *) message);
memcpy(buf, end, left);
memset(((uint8_t *) buf) + left, 0, SC_BLOCKSIZE - left);
((uint8_t *) buf)[SC_BLOCKSIZE - 1] = (uint8_t) left;
// do some final mixing
spooky_end(buf, h);
*hash1 = h[0];
*hash2 = h[1];
}
/*
// init spooky state
void
spooky_init(struct spooky_state *state, uint64_t seed1, uint64_t seed2)
{
state->length = 0;
state->left = 0;
state->state[0] = seed1;
state->state[1] = seed2;
}
// add a message fragment to the state
void
spooky_update(struct spooky_state *restrict state,
const void *restrict message, size_t length)
{
uint64_t h[SC_NUMVARS];
size_t newLength = length + state->left;
uint8_t left;
union {
const uint8_t *p8;
uint64_t *p64;
} u;
const uint64_t *end;
// Is this message fragment too short? If it is, stuff it away.
if (newLength < SC_BUFSIZE) {
memcpy(&((uint8_t *) state->data)[state->left], message, length);
state->length = length + state->length;
state->left = (uint8_t) newLength;
return;
}
// init the variables
if (state->length < SC_BUFSIZE) {
h[0] = h[3] = h[6] = h[9] = state->state[0];
h[1] = h[4] = h[7] = h[10] = state->state[1];
h[2] = h[5] = h[8] = h[11] = SC_CONST;
}
else {
memcpy(h, state->state, sizeof(state->state));
}
state->length = length + state->length;
// if we've got anything stuffed away, use it now
if (state->left) {
uint8_t prefix = SC_BUFSIZE - state->left;
memcpy(&(((uint8_t *) state->data)[state->left]), message, prefix);
u.p64 = state->data;
spooky_mix(u.p64, h);
spooky_mix(&u.p64[SC_NUMVARS], h);
u.p8 = ((const uint8_t *) message) + prefix;
length -= prefix;
}
else {
u.p8 = (const uint8_t *) message;
}
// handle all whole blocks of SC_BLOCKSIZE bytes
end = u.p64 + (length / SC_BLOCKSIZE) * SC_NUMVARS;
left = (uint8_t) (length - ((const uint8_t *) end - u.p8));
if (ALLOW_UNALIGNED_READS || spooky_is_aligned(u.p8, 8)) {
while (u.p64 < end) {
spooky_mix(u.p64, h);
u.p64 += SC_NUMVARS;
}
}
else {
while (u.p64 < end) {
memcpy(state->data, u.p8, SC_BLOCKSIZE);
spooky_mix(state->data, h);
u.p64 += SC_NUMVARS;
}
}
// stuff away the last few bytes
state->left = left;
memcpy(state->data, end, left);
// stuff away the variables
memcpy(state->state, h, sizeof(state->state));
}
// report the hash for the concatenation of all message fragments so far
void
spooky_final(struct spooky_state *restrict state,
uint64_t *restrict hash1, uint64_t *restrict hash2)
{
// init the variables
if (state->length < SC_BUFSIZE) {
*hash1 = state->state[0];
*hash2 = state->state[1];
spooky_short(state->data, state->length, hash1, hash2);
return;
}
const uint64_t *data = (const uint64_t *) state->data;
uint8_t left = state->left;
uint64_t h[SC_NUMVARS];
memcpy(h, state->state, sizeof(state->state));
if (left >= SC_BLOCKSIZE) {
// m_data can contain two blocks; handle any whole first block
spooky_mix(data, h);
data += SC_NUMVARS;
left -= SC_BLOCKSIZE;
}
// mix in the last partial block, and the length mod SC_BLOCKSIZE
memset(&((uint8_t *) data)[left], 0, (SC_BLOCKSIZE - left));
((uint8_t *) data)[SC_BLOCKSIZE - 1] = left;
// do some final mixing
spooky_end(data, h);
*hash1 = h[0];
*hash2 = h[1];
}
*/