diff --git a/src/base/errors.c b/src/base/errors.c
index 5adc0ee..4d0d2be 100644
--- a/src/base/errors.c
+++ b/src/base/errors.c
@@ -13,6 +13,7 @@ char* errname(ErrorId err){
         case ERR_ENDOFSTR: return "ERR_ENDOFSTR";
         case ERR_KEYNOTFOUND: return "ERR_KEYNOTFOUND";
         case ERR_FORMAT: return "ERR_FORMAT";
+        case ERR_UNEXPECTEDVAL: return "ERR_UNEXPECTEDVAL";
         default: return "UNKNOWN_ERROR";
     }
 }
diff --git a/src/base/errors.h b/src/base/errors.h
index 7be9aa9..4abc7df 100644
--- a/src/base/errors.h
+++ b/src/base/errors.h
@@ -11,7 +11,7 @@ typedef enum ErrorId {
     SUCCESS, // not an error 
     ERR_MAXLENGTH, ERR_WRONGTYPE, ERR_WRONGINDEX, 
     ERR_NOTIMPLEMENTED, ERR_NULLPTR, ERR_ENDOFSTR, 
-    ERR_KEYNOTFOUND, ERR_FORMAT
+    ERR_KEYNOTFOUND, ERR_FORMAT, ERR_UNEXPECTEDVAL
 } ErrorId;
 
 char* errname(ErrorId err);
diff --git a/src/random/krandom.c b/src/random/krandom.c
new file mode 100644
index 0000000..3801717
--- /dev/null
+++ b/src/random/krandom.c
@@ -0,0 +1,6 @@
+#include "krandom.h"
+
+bool fate(float chance){
+    int limit=1/chance + 0.01f;
+    return rand()%limit == 0;
+}
diff --git a/src/random/krandom.h b/src/random/krandom.h
new file mode 100644
index 0000000..4815468
--- /dev/null
+++ b/src/random/krandom.h
@@ -0,0 +1,91 @@
+#pragma once
+
+#if __cplusplus
+extern "C" {
+#endif
+
+#include "../base/std.h"
+
+/*
+You can choose any algorithm that has required functions:
+
+    some_alg64_state some_alg64_init(uint64 seed);
+    uint64 some_alg64_next(some_alg64_state);
+
+    #define KRAND_ALG64 some_alg64
+    #include "kerep/random/krandom.h"
+
+The same way it works for 32-bit RNGs:
+
+    some_alg64_state some_alg32_init(uint32 seed);
+    uint32 some_alg32_next(some_alg64_state);
+
+    #define KRAND_ALG32 some_alg32
+    #include "kerep/random/krandom.h"
+*/
+
+// default rng_next function
+#ifndef KRAND_ALG32
+    #define KRAND_ALG32 xoroshiro128plus
+#endif
+#ifndef KRAND_ALG64
+    #define KRAND_ALG64 xoshiro128plus
+#endif
+
+typedef void* KRAND_ALG32_state;
+typedef void* KRAND_ALG64_state;
+#define KRAND_ALG32_next(STATE)    xoshiro128plus##_next(STATE)
+#define KRAND_ALG32_init(SEED)     xoshiro128plus##_init(SEED)
+#define KRAND_ALG32_initFromTime() xoshiro128plus##_initFromTime()
+#define KRAND_ALG64_next(STATE)    xoshiro256plus##_next(STATE)
+#define KRAND_ALG64_init(SEED)     xoshiro256plus##_init(SEED)
+#define KRAND_ALG64_initFromTime() xoshiro256plus##_initFromTime()
+
+
+#define __krand_declare_alg(ALG, VALUE_SIZE)\
+    typedef void* ALG##_state;\
+    ALG##_state ALG##_init(uint64 seed);\
+    static inline ALG##_state  ALG##_initFromTime(void) { return ALG##_init(time(NULL)); }\
+    uint##VALUE_SIZE ALG##_next(ALG##_state);
+
+// different algorithm declarations
+// for ALG32
+    // xoroshiro64
+__krand_declare_alg(xoroshiro64star,      32)
+__krand_declare_alg(xoroshiro64starstar,  32)
+    // xoshiro128
+__krand_declare_alg(xoshiro128plus,       32)
+__krand_declare_alg(xoshiro128plusplus,   32)
+__krand_declare_alg(xoshiro128starstar,   32)
+// for ALG64
+    // xoroshiro128
+__krand_declare_alg(xoroshiro128plus,     64)
+__krand_declare_alg(xoroshiro128plusplus, 64)
+__krand_declare_alg(xoroshiro128starstar, 64)
+    // xoshiro256
+__krand_declare_alg(xoshiro256plus,       64)
+__krand_declare_alg(xoshiro256plusplus,   64)
+__krand_declare_alg(xoshiro256starstar,         64)
+    // splitmix64
+__krand_declare_alg(splitmix64, 64)
+
+
+#define __krand_next_definition(VALUE_SIZE) { return from+KRAND_ALG##VALUE_SIZE##_next(state)%(to-from); }
+
+// ready-to-use functions
+static inline int8  krand_next8 (KRAND_ALG32_state state, int8  from, int8  to) __krand_next_definition(32)
+static inline int16 krand_next16(KRAND_ALG32_state state, int16 from, int16 to) __krand_next_definition(32)
+static inline int32 krand_next32(KRAND_ALG32_state state, int32 from, int32 to) __krand_next_definition(32)
+static inline int64 krand_next64(KRAND_ALG64_state state, int64 from, int64 to) __krand_next_definition(64)
+
+// divides random number by 2^64 to return a value between 0 and 1
+static inline float32 krand_nextFloat32(KRAND_ALG32_state state) {return (uint32)KRAND_ALG32_next(state)/0xffffffff; }
+static inline float64 krand_nextFloat64(KRAND_ALG64_state state) {return KRAND_ALG64_next(state)/0xffffffff; }
+
+
+///@param chance (0-1.0) is probability of success
+bool fate(float chance);
+
+#if __cplusplus
+}
+#endif
\ No newline at end of file
diff --git a/src/random/splitmix64.c b/src/random/splitmix64.c
new file mode 100644
index 0000000..cb89ed4
--- /dev/null
+++ b/src/random/splitmix64.c
@@ -0,0 +1,35 @@
+#include "krandom.h"
+
+/* 
+This is a fixed-increment version of Java 8's SplittableRandom generator
+See http://dx.doi.org/10.1145/2714064.2660195 and
+http://docs.oracle.com/javase/8/docs/api/java/util/SplittableRandom.html
+It is a very fast generator passing BigCrush, and it can be useful if
+for some reason you absolutely want 64 bits of state; otherwise, we
+rather suggest to use a xoroshiro128+ (for moderately parallel
+computations) or xorshift1024* (for massively parallel computations)
+generator. 
+*/
+
+// The state can be seeded with any (upto) 64 bit integer value.
+typedef uint64 _state_t;
+
+void* splitmix64_init(uint64 seed){
+    _state_t* state=malloc(sizeof(_state_t));
+    *state=seed;
+    return state;
+}
+
+uint64 splitmix64_next(void* _state) {
+    _state_t* state=_state;
+    // increment the state variable
+    *state += 0x9e3779b97f4a7c15;
+    // copy the state to a working variable
+    uint64 z = *state;
+    // xor the variable with the variable right bit shifted 30 then multiply by a constant
+    z = (z ^ (z>>30)) * 0xbf58476d1ce4e5b9;
+    // xor the variable with the variable right bit shifted 27 then multiply by a constant
+    z = (z ^ (z>>27)) * 0x94d049bb133111eb;
+    // return the variable xored with itself right bit shifted 31
+    return z ^ (z>>31);
+}
diff --git a/src/random/xoroshiro/32bitValue/xoroshiro64star.c b/src/random/xoroshiro/32bitValue/xoroshiro64star.c
new file mode 100644
index 0000000..89bb6cc
--- /dev/null
+++ b/src/random/xoroshiro/32bitValue/xoroshiro64star.c
@@ -0,0 +1,53 @@
+/*  Written in 2016 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 xoroshiro64* 1.0, our best and fastest 32-bit small-state
+generator for 32-bit floating-point numbers. We suggest to use its
+upper bits for floating-point generation, as it is slightly faster than
+xoroshiro64**. It passes all tests we are aware of except for linearity
+tests, as the lowest six bits have low linear complexity, so if low
+linear complexity is not considered an issue (as it is usually the
+case) it can be used to generate 32-bit outputs, too.
+
+We suggest to use a sign test to extract a random Boolean value, and
+right shifts to extract subsets of bits.
+
+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;
+    uint32 s[2];
+} _state_t;
+
+uint32 xoroshiro64star_next(void* _state) {
+    _state_t* state=_state;
+    const uint32 s0 = state->s[0];
+    uint32 s1 = state->s[1];
+    const uint32 result = s0 * 0x9E3779BB;
+
+    s1 ^= s0;
+    state->s[0] = rotl(s0, 26) ^ s1 ^ (s1 << 9); // a, b
+    state->s[1] = rotl(s1, 13); // c
+
+    return result;
+}
+
+void* xoroshiro64star_init(uint64 seed){
+    _state_t* state=malloc(sizeof(_state_t));
+    splitmix64_state splitmix=splitmix64_init(seed);
+    state->merged=splitmix64_next(splitmix);
+    return state;
+}
diff --git a/src/random/xoroshiro/32bitValue/xoroshiro64starstar.c b/src/random/xoroshiro/32bitValue/xoroshiro64starstar.c
new file mode 100644
index 0000000..6edcd59
--- /dev/null
+++ b/src/random/xoroshiro/32bitValue/xoroshiro64starstar.c
@@ -0,0 +1,49 @@
+/*  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 xoroshiro64** 1.0, our 32-bit all-purpose, rock-solid,
+   small-state generator. It is extremely fast and it passes all tests we
+   are aware of, but its state space is not large enough for any parallel
+   application.
+
+   For generating just single-precision (i.e., 32-bit) floating-point
+   numbers, xoroshiro64* 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;
+    uint32 s[2];
+} _state_t;
+
+uint32 xoroshiro64starstar_next(void* _state) {
+    _state_t* state=_state;
+    const uint32 s0 = state->s[0];
+    uint32 s1 = state->s[1];
+    const uint32 result = rotl(s0 * 0x9E3779BB, 5) * 5;
+
+    s1 ^= s0;
+    state->s[0] = rotl(s0, 26) ^ s1 ^ (s1 << 9); // a, b
+    state->s[1] = rotl(s1, 13); // c
+
+    return result;
+}
+
+void* xoroshiro64starstar_init(uint64 seed){
+    _state_t* state=malloc(sizeof(_state_t));
+    splitmix64_state splitmix=splitmix64_init(seed);
+    state->merged=splitmix64_next(splitmix);
+    return state;
+}
diff --git a/src/random/xoroshiro/64bitValue/xoroshiro128plus.c b/src/random/xoroshiro/64bitValue/xoroshiro128plus.c
new file mode 100644
index 0000000..cf70f65
--- /dev/null
+++ b/src/random/xoroshiro/64bitValue/xoroshiro128plus.c
@@ -0,0 +1,62 @@
+/*  Written in 2016-2018 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 xoroshiro128+ 1.0, our best and fastest small-state generator
+   for floating-point numbers, but its state space is large enough only
+   for mild parallelism. We suggest to use its upper bits for
+   floating-point generation, as it is slightly faster than
+   xoroshiro128++/xoroshiro128**. It passes all tests we are aware of
+   except for the four lower bits, which might fail linearity tests (and
+   just those), so if low linear complexity is not considered an issue (as
+   it is usually the case) it can be used to generate 64-bit outputs, too;
+   moreover, this generator has a very mild Hamming-weight dependency
+   making our test (http://prng.di.unimi.it/hwd.php) fail after 5 TB of
+   output; we believe this slight bias cannot affect any application. If
+   you are concerned, use xoroshiro128++, xoroshiro128** or xoshiro256+.
+
+   We suggest to use a sign test to extract a random Boolean value, and
+   right shifts to extract subsets of bits.
+
+   The state must be seeded so that it is not everywhere zero. If you have
+   a 64-bit seed, we suggest to seed a splitmix64 generator and use its
+   output to fill s. 
+
+   NOTE: the parameters (a=24, b=16, b=37) of this version give slightly
+   better results in our test than the 2016 version (a=55, b=14, c=36).
+*/
+
+static inline uint64 rotl(const uint64 x, int k) {
+    return (x << k) | (x >> (64 - k));
+}
+
+typedef union {
+  uint32 s[2];
+} _state_t;
+
+uint64 xoroshiro128plus_next(void* _state){    
+    _state_t* state=_state;
+    const uint64 s0 = state->s[0];
+    uint64 s1 = state->s[1];
+    const uint64 result = s0 + s1;
+
+    s1 ^= s0;
+    state->s[0] = rotl(s0, 24) ^ s1 ^ (s1 << 16); // a, b
+    state->s[1] = rotl(s1, 37); // c
+
+    return result;
+}
+
+void* xoroshiro128plus_init(uint64 seed){
+    _state_t* state=malloc(sizeof(_state_t));
+    splitmix64_state splitmix=splitmix64_init(seed);
+    state->s[0]=splitmix64_next(splitmix);
+    state->s[1]=splitmix64_next(splitmix);
+    return state;
+}
diff --git a/src/random/xoroshiro/64bitValue/xoroshiro128plusplus.c b/src/random/xoroshiro/64bitValue/xoroshiro128plusplus.c
new file mode 100644
index 0000000..aaf384d
--- /dev/null
+++ b/src/random/xoroshiro/64bitValue/xoroshiro128plusplus.c
@@ -0,0 +1,51 @@
+/*  Written in 2019 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 xoroshiro128++ 1.0, one of our all-purpose, rock-solid,
+   small-state generators. It is extremely (sub-ns) fast and it passes all
+   tests we are aware of, but its state space is large enough only for
+   mild parallelism.
+
+   For generating just floating-point numbers, xoroshiro128+ is even
+   faster (but it has a very mild bias, see notes in the comments).
+
+   The state must be seeded so that it is not everywhere zero. If you have
+   a 64-bit seed, we suggest to seed a splitmix64 generator and use its
+   output to fill s. */
+
+
+static inline uint64 rotl(const uint64 x, int k) {
+    return (x << k) | (x >> (64 - k));
+}
+
+typedef union {
+  uint32 s[2];
+} _state_t;
+
+uint64 xoroshiro128plusplus_next(void* _state){    
+    _state_t* state=_state;
+    const uint64 s0 = state->s[0];
+    uint64 s1 = state->s[1];
+    const uint64 result = rotl(s0 + s1, 17) + s0;
+
+    s1 ^= s0;
+    state->s[0] = rotl(s0, 49) ^ s1 ^ (s1 << 21); // a, b
+    state->s[1] = rotl(s1, 28); // c
+
+    return result;
+}
+
+void* xoroshiro128plusplus_init(uint64 seed){
+    _state_t* state=malloc(sizeof(_state_t));
+    splitmix64_state splitmix=splitmix64_init(seed);
+    state->s[0]=splitmix64_next(splitmix);
+    state->s[1]=splitmix64_next(splitmix);
+    return state;
+}
diff --git a/src/random/xoroshiro/64bitValue/xoroshiro128starstar.c b/src/random/xoroshiro/64bitValue/xoroshiro128starstar.c
new file mode 100644
index 0000000..d811ab6
--- /dev/null
+++ b/src/random/xoroshiro/64bitValue/xoroshiro128starstar.c
@@ -0,0 +1,51 @@
+/*  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 xoroshiro128** 1.0, one of our all-purpose, rock-solid,
+   small-state generators. It is extremely (sub-ns) fast and it passes all
+   tests we are aware of, but its state space is large enough only for
+   mild parallelism.
+
+   For generating just floating-point numbers, xoroshiro128+ is even
+   faster (but it has a very mild bias, see notes in the comments).
+
+   The state must be seeded so that it is not everywhere zero. If you have
+   a 64-bit seed, we suggest to seed a splitmix64 generator and use its
+   output to fill s. */
+
+
+static inline uint64 rotl(const uint64 x, int k) {
+    return (x << k) | (x >> (64 - k));
+}
+
+typedef union {
+  uint32 s[2];
+} _state_t;
+
+uint64 xoroshiro128starstar_next(void* _state){    
+    _state_t* state=_state;
+    const uint64 s0 = state->s[0];
+    uint64 s1 = state->s[1];
+    const uint64 result = rotl(s0 * 5, 7) * 9;
+
+    s1 ^= s0;
+    state->s[0] = rotl(s0, 24) ^ s1 ^ (s1 << 16); // a, b
+    state->s[1] = rotl(s1, 37); // c
+
+    return result;
+}
+
+void* xoroshiro128starstar_init(uint64 seed){
+    _state_t* state=malloc(sizeof(_state_t));
+    splitmix64_state splitmix=splitmix64_init(seed);
+    state->s[0]=splitmix64_next(splitmix);
+    state->s[1]=splitmix64_next(splitmix);
+    return state;
+}
diff --git a/src/random/xoshiro-xoroshiro.md b/src/random/xoshiro-xoroshiro.md
new file mode 100644
index 0000000..269477c
--- /dev/null
+++ b/src/random/xoshiro-xoroshiro.md
@@ -0,0 +1,24 @@
+# Xoshiro/Xoroshiro RNG algorithms
+There are a bunch of versions of xoshiro/xoroshiro algorithms, which are created by [David Blackman and Sebastiano Vigna](https://prng.di.unimi.it/)
+
+
+```
+xoroshiro
+├── 32bitValue
+|   ├── xoroshiro64star.c
+|   └── xoroshiro64starstar.c
+└── 64bitValue
+    ├── xoroshiro128plus.c
+    ├── xoroshiro128plusplus.c
+    └── xoroshiro128starstar.c
+
+xoshiro
+├── 32bitValue
+│   ├── xoshiro128plus.c
+│   ├── xoshiro128plusplus.c
+│   └── xoshiro128starstar.c
+└── 64bitValue
+    ├── xoshiro256plus.c
+    ├── xoshiro256plusplus.c
+    └── xoshiro256starstar.c
+```
diff --git a/src/random/xoshiro/32bitValue/xoshiro128plus.c b/src/random/xoshiro/32bitValue/xoshiro128plus.c
new file mode 100644
index 0000000..28c90ad
--- /dev/null
+++ b/src/random/xoshiro/32bitValue/xoshiro128plus.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+ 1.0, our best and fastest 32-bit generator for 32-bit
+   floating-point numbers. We suggest to use its upper bits for
+   floating-point generation, as it is slightly faster than xoshiro128**.
+   It passes all tests we are aware of except for
+   linearity tests, as the lowest four bits have low linear complexity, so
+   if low linear complexity is not considered an issue (as it is usually
+   the case) it can be used to generate 32-bit outputs, too.
+
+   We suggest to use a sign test to extract a random Boolean value, and
+   right shifts to extract subsets of bits.
+
+   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 xoshiro128plus_next(void* _state){    
+    _state_t* state=_state;
+    const uint32 result = state->s[0] + state->s[3];
+
+    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* xoshiro128plus_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;
+}
diff --git a/src/random/xoshiro/32bitValue/xoshiro128plusplus.c b/src/random/xoshiro/32bitValue/xoshiro128plusplus.c
new file mode 100644
index 0000000..689dc06
--- /dev/null
+++ b/src/random/xoshiro/32bitValue/xoshiro128plusplus.c
@@ -0,0 +1,55 @@
+/*  Written in 2019 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++ 1.0, 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.
+
+   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 xoshiro128plusplus_next(void* _state){    
+    _state_t* state=_state;
+    const uint32 result = rotl(state->s[0] + state->s[3], 7) + state->s[0];
+
+    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* xoshiro128plusplus_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;
+}
diff --git a/src/random/xoshiro/32bitValue/xoshiro128starstar.c b/src/random/xoshiro/32bitValue/xoshiro128starstar.c
new file mode 100644
index 0000000..bf458fe
--- /dev/null
+++ b/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;
+}
diff --git a/src/random/xoshiro/64bitValue/xoshiro256plus.c b/src/random/xoshiro/64bitValue/xoshiro256plus.c
new file mode 100644
index 0000000..e6829d4
--- /dev/null
+++ b/src/random/xoshiro/64bitValue/xoshiro256plus.c
@@ -0,0 +1,61 @@
+/*  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 xoshiro256+ 1.0, our best and fastest generator for floating-point
+   numbers. We suggest to use its upper bits for floating-point
+   generation, as it is slightly faster than xoshiro256++/xoshiro256**. It
+   passes all tests we are aware of except for the lowest three bits,
+   which might fail linearity tests (and just those), so if low linear
+   complexity is not considered an issue (as it is usually the case) it
+   can be used to generate 64-bit outputs, too.
+
+   We suggest to use a sign test to extract a random Boolean value, and
+   right shifts to extract subsets of bits.
+
+   The state must be seeded so that it is not everywhere zero. If you have
+   a 64-bit seed, we suggest to seed a splitmix64 generator and use its
+   output to fill s. */
+
+
+static inline uint64 rotl(const uint64 x, int k) {
+    return (x << k) | (x >> (64 - k));
+}
+
+typedef union {
+    uint64 s[4];
+} _state_t;
+
+uint64 xoshiro256plus_next(void* _state){    
+    _state_t* state=_state;
+    const uint64 result = state->s[0] + state->s[3];
+
+    const uint64 t = state->s[1] << 17;
+
+    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], 45);
+
+    return result;
+}
+
+void* xoshiro256plus_init(uint64 seed){
+    _state_t* state=malloc(sizeof(_state_t));
+    splitmix64_state splitmix=splitmix64_init(seed);
+    state->s[0]=splitmix64_next(splitmix);
+    state->s[1]=splitmix64_next(splitmix);
+    state->s[2]=splitmix64_next(splitmix);
+    state->s[3]=splitmix64_next(splitmix);
+    return state;
+}
diff --git a/src/random/xoshiro/64bitValue/xoshiro256plusplus.c b/src/random/xoshiro/64bitValue/xoshiro256plusplus.c
new file mode 100644
index 0000000..042035c
--- /dev/null
+++ b/src/random/xoshiro/64bitValue/xoshiro256plusplus.c
@@ -0,0 +1,51 @@
+/*  Written in 2019 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 xoshiro256++ 1.0, one of our all-purpose, rock-solid generators.
+   It has excellent (sub-ns) speed, a state (256 bits) that is large
+   enough for any parallel application, and it passes all tests we are
+   aware of.
+
+   For generating just floating-point numbers, xoshiro256+ is even faster.
+
+   The state must be seeded so that it is not everywhere zero. If you have
+   a 64-bit seed, we suggest to seed a splitmix64 generator and use its
+   output to fill s. */
+
+static inline uint64 rotl(const uint64 x, int k) {
+    return (x << k) | (x>>(64 - k));
+}
+
+typedef union {
+    uint64 s[4];
+} _state_t;
+
+uint64 xoshiro256plusplus_next(void* _state) {
+    _state_t* state=_state;
+    const uint64 result=rotl(state->s[0] + state->s[3], 23) + state->s[0];
+    const uint64 t=state->s[1] << 17;
+    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], 45);
+    return result;
+}
+
+void* xoshiro256plusplus_init(uint64 seed){
+    _state_t* state=malloc(sizeof(_state_t));
+    splitmix64_state splitmix=splitmix64_init(seed);
+    state->s[0]=splitmix64_next(splitmix);
+    state->s[1]=splitmix64_next(splitmix);
+    state->s[2]=splitmix64_next(splitmix);
+    state->s[3]=splitmix64_next(splitmix);
+    return state;
+}
diff --git a/src/random/xoshiro/64bitValue/xoshiro256starstar.c b/src/random/xoshiro/64bitValue/xoshiro256starstar.c
new file mode 100644
index 0000000..625aedb
--- /dev/null
+++ b/src/random/xoshiro/64bitValue/xoshiro256starstar.c
@@ -0,0 +1,56 @@
+/*  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 xoshiro256** 1.0, one of our all-purpose, rock-solid
+   generators. It has excellent (sub-ns) speed, a state (256 bits) that is
+   large enough for any parallel application, and it passes all tests we
+   are aware of.
+
+   For generating just floating-point numbers, xoshiro256+ is even faster.
+
+   The state must be seeded so that it is not everywhere zero. If you have
+   a 64-bit seed, we suggest to seed a splitmix64 generator and use its
+   output to fill s. */
+
+static inline uint64 rotl(const uint64 x, int k) {
+    return (x << k) | (x >> (64 - k));
+}
+
+typedef union {
+    uint64 s[4];
+} _state_t;
+
+uint64 xoshiro256starstar_next(void* _state){    
+    _state_t* state=_state;
+    const uint64 result = rotl(state->s[1] * 5, 7) * 9;
+
+    const uint64 t = state->s[1] << 17;
+
+    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], 45);
+
+    return result;
+}
+
+void* xoshiro256starstar_init(uint64 seed){
+    _state_t* state=malloc(sizeof(_state_t));
+    splitmix64_state splitmix=splitmix64_init(seed);
+    state->s[0]=splitmix64_next(splitmix);
+    state->s[1]=splitmix64_next(splitmix);
+    state->s[2]=splitmix64_next(splitmix);
+    state->s[3]=splitmix64_next(splitmix);
+    return state;
+}
diff --git a/tests/main.cpp b/tests/main.cpp
index 35967c1..0ba2387 100644
--- a/tests/main.cpp
+++ b/tests/main.cpp
@@ -10,9 +10,9 @@ void test_all(){
     test_hashtable();
     test_dtsod();
     test_kprint_colors();
+    test_rng_algorithms();
     printf("\e[96m--------------------------------------\e[0m\n");
 }
-
 int main(){
     setlocale(LC_ALL, "en-US.Unicode");
     ktDescriptors_beginInit();
@@ -20,7 +20,8 @@ int main(){
     ktDescriptors_endInit();
     printf("\e[97mkerep tests are starting!\n");
     // optime("test_all",1,test_all());
-    test_kprint_colors();
+    // test_kprint_colors();
+    test_rng_algorithms();
     printf("\e[0m\n");
     return 0;
 }
diff --git a/tests/test_rng_algorithms.c b/tests/test_rng_algorithms.c
new file mode 100644
index 0000000..250def8
--- /dev/null
+++ b/tests/test_rng_algorithms.c
@@ -0,0 +1,43 @@
+#include "tests.h"
+#include "../src/random/krandom.h"
+
+
+#define test_alg(ALG, VALUE_SIZE, EXPECTED_FROM_ZERO){\
+    printf("\e[94mrng algorithm: \e[96m" #ALG "\n");\
+    ALG##_state s= ALG##_init(0);\
+    uint##VALUE_SIZE r=ALG##_next(s);\
+    printf("\e[97m  next from zero seed:");\
+    if(r!=EXPECTED_FROM_ZERO){\
+        printf("\e[91m %llu\n", (uint64)r);\
+        throw(ERR_UNEXPECTEDVAL);\
+    }\
+    printf("\e[92m %llu\n", (uint64)r);\
+    s= ALG##_initFromTime();\
+    r=ALG##_next(s);\
+    printf("\e[97m  next from time seed:\e[92m %llu\n", (uint64)r);\
+}
+
+void test_rng_algorithms(){
+    optime("test_rng_algorithms",1,({
+        printf("\e[96m--------[test_rng_algorithms]---------\n");  
+        // for ALG32      
+            // xoroshiro64
+        test_alg(xoroshiro64star, 32, 932574677ULL)
+        test_alg(xoroshiro64starstar, 32, 3183060286ULL)
+            // xoshiro128
+        test_alg(xoshiro128plus, 32, 3918949401ULL)
+        test_alg(xoshiro128plusplus, 32, 1179900579ULL)
+        test_alg(xoshiro128starstar, 32, 3737715805ULL)
+        // for ALG64
+            // xoroshiro128
+        test_alg(xoroshiro128plus, 64, 4778832803ULL)
+        test_alg(xoroshiro128plusplus, 64, 626373238705583ULL)
+        test_alg(xoroshiro128starstar, 64, 11897572417920ULL)
+            // xoshiro256
+        test_alg(xoshiro256plus, 64, 15757075719729598363ULL)
+        test_alg(xoshiro256plusplus, 64, 5987356902031041503ULL)
+        test_alg(xoshiro256starstar, 64, 11091344671253066420ULL)
+            // splitmix64
+        test_alg(splitmix64, 64, 16294208416658607535ULL)
+    }));
+}
\ No newline at end of file
diff --git a/tests/tests.h b/tests/tests.h
index 584d8c4..db46e93 100644
--- a/tests/tests.h
+++ b/tests/tests.h
@@ -15,6 +15,7 @@ void test_hashtable();
 void test_dtsod();
 void test_kprint_colors();
 void test_autoarrVsVector();
+void test_rng_algorithms();
 
 #define PRINT_SIZEOF(T) printf("\e[94m" #T " size: \e[96m" IFWIN("%llu", "%lu") "\n", sizeof(T))