fast_frandom() always returns float, not floating_t
[pachi/t.git] / random.h
blobd00a4a49f1dbefa7cd04dcb33fcd00378385dd9b
1 #ifndef PACHI_RANDOM_H
2 #define PACHI_RANDOM_H
4 #include <stdint.h>
6 #include "util.h"
8 void fast_srandom(unsigned long seed);
9 unsigned long fast_getseed(void);
11 /* Note that only 16bit numbers can be returned. */
12 uint16_t fast_random(unsigned int max);
13 /* Use this one if you want larger numbers. */
14 static uint32_t fast_irandom(unsigned int max);
16 /* Get random number in [0..1] range. */
17 float fast_frandom();
20 static inline uint32_t
21 fast_irandom(unsigned int max)
23 if (max <= 65536)
24 return fast_random(max);
25 int himax = (max - 1) / 65536;
26 uint16_t hi = fast_random(himax + 1);
27 return ((uint32_t)hi << 16) | fast_random(hi < himax ? 65536 : max % 65536);
30 #endif