blaze.js

/*
    BlazeHash (64-bit) - still experimental and subject to change.
    (c) 2018-2024 bryc (github.com/bryc)
    License: Public domain. Attribution appreciated.
    Intended for blazing fast hashing of byte arrays. Produces two uncorrelated 32-bit hashes in parallel.
*/

function BlazeHash(key, seed = 0) {
    let h1 = 0xcafebabe ^ seed, h2 = 0xdeadbeef ^ seed, i = 0;
    for(let b = key.length & -8; i < b; i += 8) {
        h1 ^= key[i+3] << 24 | key[i+2] << 16 | key[i+1] << 8 | key[i  ];
        h2 ^= key[i+7] << 24 | key[i+6] << 16 | key[i+5] << 8 | key[i+4];
        h1 ^= Math.imul(h2 ^ (h2 >>> 15), 0xca9b4735);
        h2 ^= Math.imul(h1 ^ (h1 >>> 16), 0x38b34ae5);
    }
    switch(key.length & 7) {
        case 7: h2 ^= key[i+6] << 16;
        case 6: h2 ^= key[i+5] << 8;
        case 5: h2 ^= key[i+4];
        case 4: h1 ^= key[i+3] << 24;
        case 3: h1 ^= key[i+2] << 16;
        case 2: h1 ^= key[i+1] << 8;
        case 1: h1 ^= key[i];
        h1 ^= Math.imul(h2 ^ (h2 >>> 15), 0xca9b4735);
        h2 ^= Math.imul(h1 ^ (h1 >>> 16), 0x38b34ae5);
    }
    h1 ^= key.length ^ h2;
    h1 ^= Math.imul(h1 ^ (h2 >>> 15), 0x735a2d97);
    h2 ^= Math.imul(h2 ^ (h1 >>> 15), 0xcaf649a9);
    h1 ^= h2 >>> 16; h2 ^= h1 >>> 16;
    return [h1 >>> 0, h2 >>> 0];
    //return 2097152 * (h2 >>> 0) + (h1 >>> 11);
}

// BlazeHashB
// An alternate version that reads 4 bytes at a time instead of 8. Not as fast.

function BlazeHashB(key, seed = 0) {
    var h1 = 0xcafebabe ^ seed, h2 = 0xdeadbeef ^ seed;
    for(var k, i = 0, b = key.length & -4; i < b; i += 4) {
        k = key[i+3] << 24 | key[i+2] << 16 | key[i+1] << 8 | key[i];
        h1 ^= k; h1 = Math.imul(h1 ^ h1 >>> 16, 597399067) ^ h2;
        h2 ^= k; h2 = Math.imul(h2 ^ h2 >>> 24, 374761393) ^ h1;
    }
    k = 0;
    switch(key.length & 3) {
        case 3: k ^= key[i+2] << 16;
        case 2: k ^= key[i+1] << 8;
        case 1: k ^= key[i];
        h1 ^= k; h1 = Math.imul(h1 ^ h1 >>> 16, 597399067) ^ h2;
        h2 ^= k; h2 = Math.imul(h2 ^ h2 >>> 24, 374761393) ^ h1;
    }
    h1 ^= key.length;
    h1 ^= Math.imul(h1 ^ (h2 >>> 15), 0x735a2d97);
    h2 ^= Math.imul(h2 ^ (h1 >>> 15), 0xcaf649a9);
    h1 ^= h2 >>> 16; h2 ^= h1 >>> 16;
    return 2097152 * (h2 >>> 0) + (h1 >>> 11);
}