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author | rsc <devnull@localhost> | 2004-03-21 14:04:56 +0000 |
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committer | rsc <devnull@localhost> | 2004-03-21 14:04:56 +0000 |
commit | 0fc65b37a1e7585ca2347bf61dcb8bc3a6b146a4 (patch) | |
tree | dd9189a823998f494082adb769451f12be056566 /src/libsec/port/nfastrand.c | |
parent | 768206abfcf505fb034a0151bf263bc0b1f2380c (diff) | |
download | plan9port-0fc65b37a1e7585ca2347bf61dcb8bc3a6b146a4.tar.gz plan9port-0fc65b37a1e7585ca2347bf61dcb8bc3a6b146a4.tar.bz2 plan9port-0fc65b37a1e7585ca2347bf61dcb8bc3a6b146a4.zip |
Add most of libsec.
Diffstat (limited to 'src/libsec/port/nfastrand.c')
-rw-r--r-- | src/libsec/port/nfastrand.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/src/libsec/port/nfastrand.c b/src/libsec/port/nfastrand.c new file mode 100644 index 00000000..3ba77003 --- /dev/null +++ b/src/libsec/port/nfastrand.c @@ -0,0 +1,23 @@ +#include <u.h> +#include <libc.h> +#include <libsec.h> + +#define Maxrand ((1UL<<31)-1) + +ulong +nfastrand(ulong n) +{ + ulong m, r; + + /* + * set m to the maximum multiple of n <= 2^31-1 + * so we want a random number < m. + */ + if(n > Maxrand) + sysfatal("nfastrand: n too large"); + + m = Maxrand - Maxrand % n; + while((r = fastrand()) >= m) + ; + return r%n; +} |