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authorTaru Karttunen <taruti@taruti.net>2011-03-30 15:46:40 +0300
committerTaru Karttunen <taruti@taruti.net>2011-03-30 15:46:40 +0300
commite5888a1ffdae813d7575f5fb02275c6bb07e5199 (patch)
treed8d51eac403f07814b9e936eed0c9a79195e2450 /sys/src/cmd/unix/drawterm/libsec/nfastrand.c
Import sources from 2011-03-30 iso image
Diffstat (limited to 'sys/src/cmd/unix/drawterm/libsec/nfastrand.c')
-rwxr-xr-xsys/src/cmd/unix/drawterm/libsec/nfastrand.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/sys/src/cmd/unix/drawterm/libsec/nfastrand.c b/sys/src/cmd/unix/drawterm/libsec/nfastrand.c
new file mode 100755
index 000000000..fa042b00c
--- /dev/null
+++ b/sys/src/cmd/unix/drawterm/libsec/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)
+ abort();
+
+ m = Maxrand - Maxrand % n;
+ while((r = fastrand()) >= m)
+ ;
+ return r%n;
+}