TESTSIZE
TestBuf = calloc(1, TESTSIZE);
FlagBuf = calloc(1, TESTSIZE / 4096);
beg = random() & (TESTSIZE - 1) & ~4095L;
len = random() & (TESTSIZE - 1) & ~4095L;
if (beg + len > TESTSIZE)
len = TESTSIZE - beg;
for (i = 0; i < TESTSIZE; i += 4096) {
TestBuf = malloc(TESTSIZE);