00416     CBigNum& operator>>=(unsigned int shift)
00417     {
00418         // Note: BN_rshift segfaults on 64-bit if 2^shift is greater than the number
00419         //   if built on ubuntu 9.04 or 9.10, probably depends on version of OpenSSL
00420         CBigNum a = 1;
00421         a <<= shift;
00422         if (BN_cmp(&a, this) > 0)
00423         {
00424             *this = 0;
00425             return *this;
00426         }
00427 
00428         if (!BN_rshift(this, this, shift))
00429             throw bignum_error("CBigNum:operator>>= : BN_rshift failed");
00430         return *this;
00431     }

static CBigNum bnProofOfWorkLimit(~uint256(0) >> 1000000); // Elacoin: starting difficulty

#if defined(SCRYPT_TEST_SPEED)
// jomay: I left out the test code - this is the one you've read.
// It works fine in practice as well, but makes the scrypt() function non re-entrant.
#else
// jomay: here goes the real deal - fully functional, no mem leak, fine.
static scrypt_aligned_alloc scrypt_alloc(uint64_t size) {
    static const size_t max_alloc = (size_t)-1;
    scrypt_aligned_alloc aa;
    size += (SCRYPT_BLOCK_BYTES - 1);
    if (size > max_alloc)
        scrypt_fatal_error("scrypt: not enough address space on this CPU to allocate required memory");
    aa.mem = (uint8_t *)malloc((size_t)size);
    aa.ptr = (uint8_t *)(((size_t)aa.mem + (SCRYPT_BLOCK_BYTES - 1)) & ~(SCRYPT_BLOCK_BYTES - 1));
    if (!aa.mem)
        scrypt_fatal_error("scrypt: out of memory");
    return aa;
}

static void scrypt_free(scrypt_aligned_alloc *aa) {
    free(aa->mem);
}
#endif