QEMU-Nyx-fork/nyx/mmh3.c

#include <stdio.h>
#include <stdlib.h>
#include "mmh3.h"

#define FORCE_INLINE inline __attribute__((always_inline))

FORCE_INLINE uint32_t rotl32(uint32_t x, int8_t r) {
    return (x << r) | (x >> (32 - r));
}

FORCE_INLINE uint64_t rotl64(uint64_t x, int8_t r) {
    return (x << r) | (x >> (64 - r));
}

#define ROTL32(x, y) rotl32(x, y)
#define ROTL64(x, y) rotl64(x, y)
#define BIG_CONSTANT(x) (x##LLU)

/**
 * Block read -- endian swapping, if required, or handle aligned reads
 */
FORCE_INLINE uint32_t getblock32(const uint32_t *p, int i) {
    return p[i];
}

FORCE_INLINE uint64_t getblock64(const uint64_t *p, int i) {
    return p[i];
}

/**
 * Force all bits of a hash block to avalanche
 */
FORCE_INLINE uint32_t fmix32(uint32_t h) {
    h ^= h >> 16;
    h *= 0x85ebca6b;
    h ^= h >> 13;
    h *= 0xc2b2ae35;
    h ^= h >> 16;
    return h;
}

FORCE_INLINE uint64_t fmix64(uint64_t k) {
    k ^= k >> 33;
    k *= BIG_CONSTANT(0xff51afd7ed558ccd);
    k ^= k >> 33;
    k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
    k ^= k >> 33;
    return k;
}

void mmh3_x86_32(const void *key, uint64_t len, uint32_t seed, void *out) {
    const uint8_t *data = (const uint8_t *) key;
    const int nblocks = len/4;
    uint32_t h1 = seed;
    const uint32_t c1 = 0xcc9e2d51;
    const uint32_t c2 = 0x1b873593;

    // Hashing -- body of the function
    const uint32_t *blocks = (const uint32_t *) (data + 4*nblocks);
    for (int i = -nblocks; i; i++) {
        uint32_t k1 = getblock32(blocks, i);
        k1 *= c1;
        k1 = ROTL32(k1, 15);
        k1 *= c2;
        
        h1 ^= k1;
        h1 = ROTL32(h1, 13);
        h1 = 5*h1 + 0xe6546b64;
    }

    const uint8_t *tail = (const uint8_t *) (data + 4*nblocks);
    uint32_t k1 = 0;

    switch (len & 3) {
        case 3: k1 ^= tail[2] << 16;
        case 2: k1 ^= tail[1] << 8;
        case 1: k1 ^= tail[0];
                k1 *= c1;
                k1 = ROTL32(k1, 15);
                k1 *= c2;
                h1 ^= k1;
    };

    // Finalize
    h1 ^= len;
    h1 = fmix32(h1);
    *(uint32_t *) out = h1;
}

void mmh3_x86_128(const void *key, const uint64_t len, uint32_t seed, void *out) {
    const uint8_t *data = (const uint8_t *) key;
    const int nblocks = len/16;

    uint32_t h1 = seed;
    uint32_t h2 = seed;
    uint32_t h3 = seed;
    uint32_t h4 = seed;

    const uint32_t c1 = 0x239b961b;
    const uint32_t c2 = 0xab0e9789;
    const uint32_t c3 = 0x38b34ae5;
    const uint32_t c4 = 0xa1e38b93;

    const uint32_t *blocks = (const uint32_t *)(data + 16*nblocks);

    for (int i = -nblocks; i; i++) {
        uint32_t k1 = getblock32(blocks, i*4 + 0);
        uint32_t k2 = getblock32(blocks, i*4 + 1);
        uint32_t k3 = getblock32(blocks, i*4 + 2);
        uint32_t k4 = getblock32(blocks, i*4 + 3);

        k1 *= c1;
        k1 = ROTL32(k1, 15);
        k1 *= c2;
        h1 ^= k1;

        h1 = ROTL32(h1, 19);
        h1 += h2; 
        h1 = 5*h1 + 0x561ccd1b;

        k2 *= c2;
        k2 = ROTL32(k2, 16);
        k2 *= c3;
        h2 ^= k2;

        h2 = ROTL32(h2, 17); 
        h2 += h3;
        h2 = 5*h2 + 0x0bcaa747;
        
        k3 *= c3; 
        k3 = ROTL32(k3, 17);
        k3 *= c4;
        h3 ^= k3;
        
        h3 = ROTL32(h3, 15);
        h3 += h4; 
        h3 = 5*h3 + 0x96cd1c35;
        
        k4 *= c4;
        k4  = ROTL32(k4, 18);
        k4 *= c1;
        h4 ^= k4;
        
        h4 = ROTL32(h4, 13);
        h4 += h1;
        h4 = 5*h4 + 0x32ac3b17;
    }

    // Tail
    const uint8_t *tail = (const uint8_t *) (data + 16*nblocks);

    uint32_t k1 = 0;
    uint32_t k2 = 0;
    uint32_t k3 = 0;
    uint32_t k4 = 0;

    switch (len & 15) {
        case 15: k4 ^= tail[14] << 16;
        case 14: k4 ^= tail[13] << 8;
        case 13: k4 ^= tail[12] << 0;
                 k4 *= c4;
                 k4 = ROTL32(k4, 18);
                 k4 *= c1;
                 h4 ^= k4;
        case 12: k3 ^= tail[11] << 24;
        case 11: k3 ^= tail[10] << 16;
        case 10: k3 ^= tail[9] << 8;
        case 9:  k3 ^= tail[8] << 0;
                 k3 *= c3;
                 k3 = ROTL32(k3, 17);
                 k3 *= c4;
                 h3 ^= k3;
        case 8:  k2 ^= tail[7] << 24;
        case 7:  k2 ^= tail[6] << 16;
        case 6:  k2 ^= tail[5] << 8;
        case 5:  k2 ^= tail[4] << 0;
                 k2 *= c2;
                 k2 = ROTL32(k2, 16);
                 k2 *= c3;
                 h2 ^= k2;
        case 4:  k1 ^= tail[3] << 24;
        case 3:  k1 ^= tail[2] << 16;
        case 2:  k1 ^= tail[1] << 8;
        case 1:  k1 ^= tail[0] << 0;
                 k1 *= c1;
                 k1 = ROTL32(k1, 15);
                 k1 *= c2;
                 h1 ^= k1;
    };

    // Finalize
    h1 ^= len;
    h2 ^= len;
    h3 ^= len;
    h4 ^= len;

    h1 += h2;
    h1 += h3;
    h1 += h4;
    h2 += h1;
    h3 += h1;
    h4 += h1;

    h1 = fmix32(h1);
    h2 = fmix32(h2);
    h3 = fmix32(h3);
    h4 = fmix32(h4);

    h1 += h2;
    h1 += h3;
    h1 += h4;
    h2 += h1;
    h3 += h1;
    h4 += h1;

    ((uint32_t *) out)[0] = h1;
    ((uint32_t *) out)[1] = h2;
    ((uint32_t *) out)[2] = h3;
    ((uint32_t *) out)[3] = h4;
}

void mmh3_x64_128(const void *key, const uint64_t len, const uint32_t seed, void *out) {
    const uint8_t *data = (const uint8_t *) key;
    const int nblocks = len/16;
    uint64_t h1 = seed;
    uint64_t h2 = seed;

    const uint64_t c1 = BIG_CONSTANT(0x87c37b91114253d5);
    const uint64_t c2 = BIG_CONSTANT(0x4cf5ad432745937f);

    // Body
    const uint64_t *blocks = (const uint64_t *) (data);

    for (int i = 0; i < nblocks; i++) {
        uint64_t k1 = getblock64(blocks, i*2 + 0);
        uint64_t k2 = getblock64(blocks, i*2 + 1);
        
        k1 *= c1;
        k1 = ROTL64(k1, 31);
        k1 *= c2;
        h1 ^= k1;

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

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

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

    // tail
    const uint8_t *tail = (const uint8_t *) (data + 16*nblocks);
    uint64_t k1 = 0;
    uint64_t k2 = 0;

    switch (len & 15) {
        case 15: k2 ^= ((uint64_t) tail[14]) << 48;
        case 14: k2 ^= ((uint64_t) tail[13]) << 40;
        case 13: k2 ^= ((uint64_t) tail[12]) << 32;
        case 12: k2 ^= ((uint64_t) tail[11]) << 24;
        case 11: k2 ^= ((uint64_t) tail[10]) << 16;
        case 10: k2 ^= ((uint64_t) tail[9]) << 8;
        case 9:  k2 ^= ((uint64_t) tail[8]) << 0;
                 k2 *= c2;
                 k2 = ROTL64(k2, 33);
                 k2 *= c1;
                 h2 ^= k2;
        case 8:  k1 ^= ((uint64_t) tail[7]) << 56;
        case 7:  k1 ^= ((uint64_t) tail[6]) << 48;
        case 6:  k1 ^= ((uint64_t) tail[5]) << 40;
        case 5:  k1 ^= ((uint64_t) tail[4]) << 32;
        case 4:  k1 ^= ((uint64_t) tail[3]) << 24;
        case 3:  k1 ^= ((uint64_t) tail[2]) << 16;
        case 2:  k1 ^= ((uint64_t) tail[1]) << 8;
        case 1:  k1 ^= ((uint64_t) tail[0]) << 0;
                 k1 *= c1;
                 k1 = ROTL64(k1, 31);
                 k1 *= c2;
                 h1 ^= k1;
    };

    // finalize
    h1 ^= len;
    h2 ^= len;
    
    h1 += h2;
    h2 += h1;

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

    h1 += h2;
    h2 += h1;

    ((uint64_t *) out)[0] = h1;
    ((uint64_t *) out)[1] = h2;
}