1 // cl_LF_len_incsqrt().
12 uintC cl_LF_len_incsqrt (uintC n)
14 // Methode bei intDsize=16:
15 // n -> n+1 für n<=12 wegen 16n+sqrt(16n)+2 < 16(n+1)
16 // n -> n+2 für n<=56 wegen 16n+sqrt(16n)+2 < 16(n+2)
17 // n -> n+4 für n<=240
18 // n -> n+8 für n<=992
19 // n -> n+16 für n<=4032
20 // n -> n+32 für n<=16256
21 // n -> n+65 für n<=65535
22 // Allgemein: intDsize*n + sqrt(intDsize*n) + 2 < intDsize*(n+inc)
23 // <==> sqrt(intDsize*n) + 2 < intDsize*inc
24 // <==> sqrt(intDsize*n) < intDsize*inc - 2
25 // <==> intDsize*n < intDsize^2*inc^2 - 4*intDsize*inc + 4
26 // <==> n <= intDsize*inc^2 - 4*inc
28 #define NMAX(k) (uintL)((intDsize*(k)-4)*(k))
29 #define FITS(n,k) ((n) <= NMAX(k))
30 #define n_max (uintL)(bitm(intCsize)-1)
31 #define TRYINC(inc) FITS(n_max,inc) || FITS(n,inc) ? RETINC(inc) :
33 /* at this point we know n <= NMAX(inc) */ \
34 /* Check whether n + (inc) overflows. */ \
35 ((NMAX(inc) <= n_max-(inc)) || (n <= n_max-(inc)) ? n+(inc) : n_max)
36 #define TEST(i) TRYINC(1UL<<i)
51 // No TEST(14), because NMAX(1UL<<14) is already out of range.