added random number generation algorithms

src/random/xoshiro/32bitValue/xoshiro128starstar.c

@@ -0,0 +1,58 @@
+/*  Written in 2018 by David Blackman and Sebastiano Vigna (vigna@acm.org)
+
+To the extent possible under law, the author has dedicated all copyright
+and related and neighboring rights to this software to the public domain
+worldwide. This software is distributed without any warranty.
+
+See <http://creativecommons.org/publicdomain/zero/1.0/>. */
+
+#include "../../krandom.h"
+
+/* This is xoshiro128** 1.1, one of our 32-bit all-purpose, rock-solid
+   generators. It has excellent speed, a state size (128 bits) that is
+   large enough for mild parallelism, and it passes all tests we are aware
+   of.
+
+   Note that version 1.0 had mistakenly state->s[0] instead of state->s[1] as state
+   word passed to the scrambler.
+
+   For generating just single-precision (i.e., 32-bit) floating-point
+   numbers, xoshiro128+ is even faster.
+
+   The state must be seeded so that it is not everywhere zero. */
+
+
+static inline uint32 rotl(const uint32 x, int k) {
+    return (x << k) | (x >> (32 - k));
+}
+
+typedef union {
+    uint64 merged[2];
+    uint32 s[4];
+} _state_t;
+
+uint32 xoshiro128starstar_next(void* _state){    
+    _state_t* state=_state;
+    const uint32 result = rotl(state->s[1] * 5, 7) * 9;
+
+    const uint32 t = state->s[1] << 9;
+
+    state->s[2] ^= state->s[0];
+    state->s[3] ^= state->s[1];
+    state->s[1] ^= state->s[2];
+    state->s[0] ^= state->s[3];
+
+    state->s[2] ^= t;
+
+    state->s[3] = rotl(state->s[3], 11);
+
+    return result;
+}
+
+void* xoshiro128starstar_init(uint64 seed){
+    _state_t* state=malloc(sizeof(_state_t));
+    splitmix64_state splitmix=splitmix64_init(seed);
+    state->merged[0]=splitmix64_next(splitmix);
+    state->merged[1]=splitmix64_next(splitmix);
+    return state;
+}