From ec16f5412b4fa1d0cdc76acb799d3cbf78e8cefd Mon Sep 17 00:00:00 2001
From: Brett <brettmaster1@gmail.com>
Date: Sun, 23 Jul 2023 13:10:11 -0400
Subject: [PATCH] new randomness functions

---
 include/blt/std/random.h | 45 ++++++++++++++++++++++++++++++++++++----
 src/tests/main.cpp       | 20 ++++++++++++++++++
 src/tests/queue_tests.h  |  2 +-
 3 files changed, 62 insertions(+), 5 deletions(-)

diff --git a/include/blt/std/random.h b/include/blt/std/random.h
index 86ca8fd..f8bd993 100755
--- a/include/blt/std/random.h
+++ b/include/blt/std/random.h
@@ -9,7 +9,41 @@
 
 #include <random>
 
-namespace blt {
+namespace blt::random {
+    
+    static inline uint32_t PCG_Hash(uint32_t input) {
+        uint32_t state = input * 747796405u + 2891336453u;
+        uint32_t word = ((state >> ((state >> 28u) + 4u)) ^ state) * 277803737u;
+        return (word >> 22u) ^
+        word;
+    }
+
+    static inline float randomFloat(uint32_t& seed){
+        seed = PCG_Hash(seed);
+        return (float)seed / (float)std::numeric_limits<uint32_t>::max();
+    }
+
+    /**
+     * @return random float without changing seed
+     */
+    static inline float randomFloat_c(uint32_t seed){
+        return randomFloat(seed);
+    }
+
+    /**
+     * @param seed seed for random
+     * @param min inclusive min
+     * @param max exclusive max
+     * @return random int between min (inclusive) and max (exclusive)
+     */
+    static inline int randomInt(uint32_t& seed, int min = 0, int max = 1){
+        return (int)((randomFloat(seed) * (float)(max - min)) + (float)min);
+    }
+
+    static inline int randomInt_c(uint32_t seed, int min = 0, int max = 1){
+        return randomInt(seed, min, max);
+    }
+
     /**
      * Creates a container class for generating random number distributions
      * @tparam T numeric type
@@ -28,17 +62,19 @@ namespace blt {
              * @param max max value possible to generate. (default: 1)
              * @param seed seed to use in generating random values. (default: 0)
              */
-            explicit random(T min = (T)0, T max = (T)1, long seed = 0): gen(std::mt19937(seed)){
+            explicit random(T min = (T) 0, T max = (T) 1, long seed = 0): gen(std::mt19937(seed)) {
                 distribution = new dist(min, max);
             }
+            
             /**
              * Note the min/max are inclusive and defaults to a **uniform** distribution.
              * @return random number between the defined min/max or the default of [0,1].
              */
-            T get(){
+            T get() {
                 return (*distribution)(gen);
             }
-            ~random(){
+            
+            ~random() {
                 delete distribution;
             }
     };
@@ -52,6 +88,7 @@ namespace blt {
             
             }
     };
+    
 }
 
 #endif //BLT_RANDOM_H
diff --git a/src/tests/main.cpp b/src/tests/main.cpp
index 5b45c52..bc4d95e 100755
--- a/src/tests/main.cpp
+++ b/src/tests/main.cpp
@@ -57,5 +57,25 @@ int main() {
     BLT_ERROR("Hello Error!");
     BLT_FATAL("Hello Fatal!");
     
+    int vals[100];
+    
+    for (int & val : vals)
+        val = 0;
+    
+    uint32_t seed = 1023;
+    for (int i = 0; i < 1203000; i++){
+        seed = seed * i;
+        vals[blt::random::randomInt(seed, 0, 100)]++;
+    }
+    
+    std::fstream csv("./randoms2.csv", std::ios::out);
+    
+    csv << "index,count\n";
+    for (int i = 0; i < 100; i++){
+        csv << i << "," << vals[i] << "\n";
+    }
+    
+    csv.close();
+    
     return 0;
 }
\ No newline at end of file
diff --git a/src/tests/queue_tests.h b/src/tests/queue_tests.h
index 052b670..758c4e8 100755
--- a/src/tests/queue_tests.h
+++ b/src/tests/queue_tests.h
@@ -129,7 +129,7 @@ static inline void random_access() {
 }
 
 static inline void test_queues() {
-    blt::random<int, std::uniform_int_distribution> rand{1, 100};
+    blt::random::random<int, std::uniform_int_distribution> rand{1, 100};
     
     for (int& value : values){
         value = rand.get();