memfryu64.c

/**
 * @example 0x1122334455667788 => 0x4477225588336611
 *
 * NB: Do not use this functin like a {cryptographic,} hash function
 */
static inline uint64_t memfryu64(uint64_t a, u8 off)
{
    uint64_t b = 0;
    for (u8 i = 0; i < sizeof(uint64_t); ++i) {
        u8 aOff = (i + ((i % 2) ? 0 : off)) % sizeof(uint64_t);
        b = (b << __CHAR_BIT__) | (u8)(a >> (__CHAR_BIT__ * aOff));
    }   
    return b;
}