From: Tyson Smith <[email protected]>
These macros will generate a random number between 0 and 2^32 - 1 or
2^64 - 1 respectively. There is also a compile time check to verify
that a full 2^n bits of randomness will be generated (depends on RAND_MAX).
---
include/random.h | 8 ++++++++
random.c | 4 ++--
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/include/random.h b/include/random.h
index dbff344..f070568 100644
--- a/include/random.h
+++ b/include/random.h
@@ -1,10 +1,18 @@
#pragma once
+#include <stdlib.h>
#include "child.h"
#include "types.h"
#define ONE_IN(x) ((rand() % x) == 0) //
limit of RAND_MAX-1
+#if RAND_MAX == 0x7FFFFFFF
+#define RAND_32() ((rand() << 1) | (rand() & 1))
+#define RAND_64() (((0ULL | rand()) << 33) |
((0ULL | rand()) << 2) | (rand() & 0x3))
+#else
+#error "Unexpected RAND_MAX value. Please add support."
+#endif
+
extern unsigned int seed;
unsigned int init_seed(unsigned int seed);
void set_seed(struct childdata *child);
diff --git a/random.c b/random.c
index 6a2e90e..f425ed5 100644
--- a/random.c
+++ b/random.c
@@ -132,7 +132,7 @@ static unsigned int __rand32(void)
break;
case 1: r = randbits(32);
break;
- case 2: r = rand();
+ case 2: r = RAND_32();
break;
case 3: r = rand8x8();
break;
@@ -216,7 +216,7 @@ u64 rand64(void)
break;
case 1: r = randbits(64);
break;
- case 2: r = rand32() | rand32() << 31;
+ case 2: r = RAND_64();
break;
case 3: r = rand8x8();
break;
--
1.9.1
--
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