diff options
Diffstat (limited to 'src/librandom')
-rw-r--r-- | src/librandom/random_uint32.c | 39 |
1 files changed, 9 insertions, 30 deletions
diff --git a/src/librandom/random_uint32.c b/src/librandom/random_uint32.c index 5fda0d3..9009a59 100644 --- a/src/librandom/random_uint32.c +++ b/src/librandom/random_uint32.c @@ -6,6 +6,7 @@ #include <skalibs/nonposix.h> #include <stdlib.h> +#include <skalibs/uint32.h> #include <skalibs/random.h> uint32 random_uint32 (uint32 n) @@ -16,43 +17,21 @@ uint32 random_uint32 (uint32 n) #else #include <skalibs/uint32.h> -#include <skalibs/bytestr.h> #include <skalibs/random.h> -static inline uint32 random_mask2 (register uint32 n) -{ - for (;;) - { - register uint32 m = n | (n >> 1) ; - if (m == n) return n ; - n = m ; - } -} - -static inline unsigned int random_nchars (register uint32 n) -{ - return n <= 0xff ? 1 : - n <= 0xffff ? 2 : - n <= 0xffffffUL ? 3 : 4 ; -} - uint32 random_uint32 (uint32 n) { - if (!n) return 0 ; - else + uint32 min, x ; + if (n < 2) return 0 ; + min = -n % n ; + for (;;) { - uint32 i = n, m = random_mask2(n-1) ; - unsigned int nchars = random_nchars(n) ; char tmp[4] ; - while (i >= n) - { - random_string(tmp, nchars) ; - byte_zero(tmp + nchars, 4 - nchars) ; - uint32_unpack(tmp, &i) ; - i &= m ; - } - return i ; + random_string(tmp, 4) ; + uint32_unpack(tmp, &x) ; + if (x >= min) break ; } + return x % n ; } #endif |