rand: add rand64_between()

[fio.git] / lib / rand.h

diff --git a/lib/rand.h b/lib/rand.h
index b99f618c000f108db5fb56adfc4bc0eaa00cad30..6be53072a64751c4ae864a439e33a374205e3c4b 100644 (file)
--- a/lib/rand.h
+++ b/lib/rand.h
@@ -2,7 +2,8 @@
 #define FIO_RAND_H
 
 #include <inttypes.h>
-#include "../arch/arch.h"
+#include <assert.h>
+#include "types.h"
 
 #define FRAND32_MAX    (-1U)
 #define FRAND64_MAX    (-1ULL)
@@ -23,10 +24,6 @@ struct frand_state {
        };
 };
 
-struct frand64_state {
-       uint64_t s1, s2, s3, s4, s5;
-};
-
 static inline uint64_t rand_max(struct frand_state *state)
 {
        if (state->use64)
@@ -104,8 +101,52 @@ static inline uint64_t __rand(struct frand_state *state)
                return __rand32(&state->state32);
 }
 
-extern void init_rand(struct frand_state *, int);
-extern void init_rand_seed(struct frand_state *, unsigned int seed, int);
+static inline double __rand_0_1(struct frand_state *state)
+{
+       if (state->use64) {
+               uint64_t val = __rand64(&state->state64);
+
+               return (val + 1.0) / (FRAND64_MAX + 1.0);
+       } else {
+               uint32_t val = __rand32(&state->state32);
+
+               return (val + 1.0) / (FRAND32_MAX + 1.0);
+       }
+}
+
+/*
+ * Generate a random value between 'start' and 'end', both inclusive
+ */
+static inline int rand32_between(struct frand_state *state, int start, int end)
+{
+       uint32_t r;
+
+       assert(!state->use64);
+
+       r = __rand32(&state->state32);
+       return start + (int) ((double)end * (r / (FRAND32_MAX + 1.0)));
+}
+
+static inline uint64_t rand64_between(struct frand_state *state, uint64_t start,
+                                     uint64_t end)
+{
+       uint64_t r;
+
+       r = __rand64(&state->state64);
+       return start + (uint64_t) ((double)end * (r / (FRAND64_MAX + 1.0)));
+}
+
+static inline uint64_t rand_between(struct frand_state *state, uint64_t start,
+                                   uint64_t end)
+{
+       if (state->use64)
+               return rand32_between(state, start, end);
+       else
+               return rand64_between(state, start, end);
+}
+
+extern void init_rand(struct frand_state *, bool);
+extern void init_rand_seed(struct frand_state *, unsigned int seed, bool);
 extern void __fill_random_buf(void *buf, unsigned int len, unsigned long seed);
 extern unsigned long fill_random_buf(struct frand_state *, void *buf, unsigned int len);
 extern void __fill_random_buf_percentage(unsigned long, void *, unsigned int, unsigned int, unsigned int, char *, unsigned int);