void SpookyHashV1::Short()

in folly/hash/SpookyHashV1.cpp [44:155]
102 lines of code
22 McCabe index (conditional complexity)

void SpookyHashV1::Short(
    const void* message,
    size_t length,
    uint64_t *hash1,
    uint64_t *hash2)
{
    uint64_t buf[2*sc_numVars];
    union
    {
        const uint8_t *p8;
        uint32_t *p32;
        uint64_t *p64;
        size_t i;
    } u;

    u.p8 = (const uint8_t *)message;

    if (!ALLOW_UNALIGNED_READS && (u.i & 0x7))
    {
        memcpy(buf, message, length);
        u.p64 = buf;
    }

    size_t remainder = length%32;
    uint64_t a=*hash1;
    uint64_t b=*hash2;
    uint64_t c=sc_const;
    uint64_t d=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)
        {
            c += u.p64[0];
            d += u.p64[1];
            ShortMix(a,b,c,d);
            a += u.p64[2];
            b += u.p64[3];
        }

        //Handle the case of 16+ remaining bytes.
        if (remainder >= 16)
        {
            c += u.p64[0];
            d += u.p64[1];
            ShortMix(a,b,c,d);
            u.p64 += 2;
            remainder -= 16;
        }
    }

    // Handle the last 0..15 bytes, and its length
    d = ((uint64_t)length) << 56;
    switch (remainder)
    {
    case 15:
        d += ((uint64_t)u.p8[14]) << 48;
        FOLLY_FALLTHROUGH;
    case 14:
        d += ((uint64_t)u.p8[13]) << 40;
        FOLLY_FALLTHROUGH;
    case 13:
        d += ((uint64_t)u.p8[12]) << 32;
        FOLLY_FALLTHROUGH;
    case 12:
        d += u.p32[2];
        c += u.p64[0];
        break;
    case 11:
        d += ((uint64_t)u.p8[10]) << 16;
        FOLLY_FALLTHROUGH;
    case 10:
        d += ((uint64_t)u.p8[9]) << 8;
        FOLLY_FALLTHROUGH;
    case 9:
        d += (uint64_t)u.p8[8];
        FOLLY_FALLTHROUGH;
    case 8:
        c += u.p64[0];
        break;
    case 7:
        c += ((uint64_t)u.p8[6]) << 48;
        FOLLY_FALLTHROUGH;
    case 6:
        c += ((uint64_t)u.p8[5]) << 40;
        FOLLY_FALLTHROUGH;
    case 5:
        c += ((uint64_t)u.p8[4]) << 32;
        FOLLY_FALLTHROUGH;
    case 4:
        c += u.p32[0];
        break;
    case 3:
        c += ((uint64_t)u.p8[2]) << 16;
        FOLLY_FALLTHROUGH;
    case 2:
        c += ((uint64_t)u.p8[1]) << 8;
        FOLLY_FALLTHROUGH;
    case 1:
        c += (uint64_t)u.p8[0];
        break;
    case 0:
        c += sc_const;
        d += sc_const;
    }
    ShortEnd(a,b,c,d);
    *hash1 = a;
    *hash2 = b;
}