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[fio.git] / lib / rand.h

diff --git a/lib/rand.h b/lib/rand.h
index 3554f6985e93ff02eacfb364054a5594007e88e5..46c1c5e023a132513ded05d885bd5769dbf7ceb9 100644 (file)
--- a/lib/rand.h
+++ b/lib/rand.h
@@ -6,7 +6,9 @@
 #include "types.h"
 
 #define FRAND32_MAX    (-1U)
+#define FRAND32_MAX_PLUS_ONE   (1.0 * (1ULL << 32))
 #define FRAND64_MAX    (-1ULL)
+#define FRAND64_MAX_PLUS_ONE   (1.0 * (1ULL << 32) * (1ULL << 32))
 
 struct taus88_state {
        unsigned int s1, s2, s3;
@@ -106,17 +108,14 @@ 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);
+               return (val + 1.0) / FRAND64_MAX_PLUS_ONE;
        } else {
                uint32_t val = __rand32(&state->state32);
 
-               return (val + 1.0) / (FRAND32_MAX + 1.0);
+               return (val + 1.0) / FRAND32_MAX_PLUS_ONE;
        }
 }
 
-/*
- * Generate a random value between 'start' and 'end', both inclusive
- */
 static inline uint32_t rand32_upto(struct frand_state *state, uint32_t end)
 {
        uint32_t r;
@@ -124,7 +123,8 @@ static inline uint32_t rand32_upto(struct frand_state *state, uint32_t end)
        assert(!state->use64);
 
        r = __rand32(&state->state32);
-       return (int) ((double)end * (r / (FRAND32_MAX + 1.0)));
+       end++;
+       return (int) ((double)end * (r / FRAND32_MAX_PLUS_ONE));
 }
 
 static inline uint64_t rand64_upto(struct frand_state *state, uint64_t end)
@@ -134,23 +134,27 @@ static inline uint64_t rand64_upto(struct frand_state *state, uint64_t end)
        assert(state->use64);
 
        r = __rand64(&state->state64);
-       return (uint64_t) ((double)end * (r / (FRAND64_MAX + 1.0)));
+       end++;
+       return (uint64_t) ((double)end * (r / FRAND64_MAX_PLUS_ONE));
 }
 
+/*
+ * Generate a random value between 'start' and 'end', both inclusive
+ */
 static inline uint64_t rand_between(struct frand_state *state, uint64_t start,
                                    uint64_t end)
 {
        if (state->use64)
-               return start + rand64_upto(state, 1 + end - start);
+               return start + rand64_upto(state, end - start);
        else
-               return start + rand32_upto(state, 1 + end - start);
+               return start + rand32_upto(state, end - start);
 }
 
 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);
-extern unsigned long fill_random_buf_percentage(struct frand_state *, void *, unsigned int, unsigned int, unsigned int, char *, unsigned int);
+extern void init_rand_seed(struct frand_state *, uint64_t seed, bool);
+extern void __fill_random_buf(void *buf, unsigned int len, uint64_t seed);
+extern uint64_t fill_random_buf(struct frand_state *, void *buf, unsigned int len);
+extern void __fill_random_buf_percentage(uint64_t, void *, unsigned int, unsigned int, unsigned int, char *, unsigned int);
+extern uint64_t fill_random_buf_percentage(struct frand_state *, void *, unsigned int, unsigned int, unsigned int, char *, unsigned int);
 
 #endif