Merge pull request #220 from scratchcpp/randomgenerator_class

Add RandomGenerator class

Author: adazem009

src/engine/CMakeLists.txt

@@ -18,5 +18,7 @@ target_sources(scratchcpp
     internal/timer.h
     internal/blocksectioncontainer.cpp
     internal/blocksectioncontainer.h
-    internal/global.h
+    internal/randomgenerator.h
+    internal/randomgenerator.cpp
+    internal/irandomgenerator.h
 )

src/engine/internal/engine.cpp

@@ -27,7 +27,6 @@ Engine::Engine() :
     m_defaultTimer(std::make_unique<Timer>()),
     m_timer(m_defaultTimer.get())
 {
-    srand(time(NULL));
 }
 
 void Engine::clear()

src/engine/internal/global.h

@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+namespace libscratchcpp
+{
+
+class IRandomGenerator
+{
+    public:
+        virtual ~IRandomGenerator() { }
+
+        virtual long randint(long start, long end) const = 0;
+        virtual double randintDouble(double start, double end) const = 0;
+};
+
+} // namespace libscratchcpp

src/engine/internal/irandomgenerator.h

@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#include <random>
+
+#include "randomgenerator.h"
+
+using namespace libscratchcpp;
+
+std::shared_ptr<RandomGenerator> RandomGenerator::m_instance = std::make_shared<RandomGenerator>();
+
+RandomGenerator::RandomGenerator() :
+    m_generator(std::make_unique<std::mt19937>(m_device()))
+{
+}
+
+std::shared_ptr<RandomGenerator> RandomGenerator::instance()
+{
+    return m_instance;
+}
+
+long RandomGenerator::randint(long start, long end) const
+{
+    if (start > end) {
+        long tmp = start;
+        start = end;
+        end = tmp;
+    }
+
+    std::uniform_int_distribution<long> distribution(start, end);
+    return distribution(*m_generator);
+}
+
+double RandomGenerator::randintDouble(double start, double end) const
+{
+    if (start > end) {
+        double tmp = start;
+        start = end;
+        end = tmp;
+    }
+
+    std::uniform_real_distribution<double> distribution(start, end);
+    return distribution(*m_generator);
+}

src/engine/internal/randomgenerator.cpp

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <memory>
+#include <random>
+
+#include "irandomgenerator.h"
+
+namespace libscratchcpp
+{
+
+class RandomGenerator : public IRandomGenerator
+{
+    public:
+        RandomGenerator();
+        RandomGenerator(const RandomGenerator &) = delete;
+
+        static std::shared_ptr<RandomGenerator> instance();
+
+        long randint(long start, long end) const override;
+        double randintDouble(double start, double end) const override;
+
+    private:
+        static std::shared_ptr<RandomGenerator> m_instance;
+        std::random_device m_device;
+        std::unique_ptr<std::mt19937> m_generator;
+};
+
+} // namespace libscratchcpp

src/engine/internal/randomgenerator.h

@@ -5,8 +5,6 @@
 #include <vector>
 #include <scratchcpp/value.h>
 
-#include "engine/internal/global.h"
-
 namespace libscratchcpp
 {
 

src/engine/script_p.h

@@ -8,7 +8,7 @@
 #include <cassert>
 
 #include "virtualmachine_p.h"
-#include "internal/global.h"
+#include "internal/randomgenerator.h"
 
 #define MAX_REG_COUNT 1024
 
@@ -29,6 +29,8 @@ using namespace vm;
 
 static const double pi = std::acos(-1); // TODO: Use std::numbers::pi in C++20
 
+IRandomGenerator *VirtualMachinePrivate::rng = nullptr;
+
 const unsigned int VirtualMachinePrivate::instruction_arg_count[] = {
     0, // OP_START
     0, // OP_HALT
@@ -106,6 +108,9 @@ VirtualMachinePrivate::VirtualMachinePrivate(VirtualMachine *vm, Target *target,
         regs[i] = new Value();
     loops.reserve(256);
     callTree.reserve(1024);
+
+    if (!rng)
+        rng = RandomGenerator::instance().get();
 }
 
 VirtualMachinePrivate::~VirtualMachinePrivate()
@@ -360,7 +365,7 @@ do_loop_end : {
     DISPATCH();
 
 do_random:
-    REPLACE_RET_VALUE(randint<long>(READ_REG(0, 2)->toDouble(), READ_REG(1, 2)->toDouble()), 2);
+    REPLACE_RET_VALUE(rng->randint(READ_REG(0, 2)->toDouble(), READ_REG(1, 2)->toDouble()), 2);
     FREE_REGS(1);
     DISPATCH();
 
@@ -539,7 +544,7 @@ do_list_del : {
             index = 0;
         } else if (str == "random") {
             size_t size = list->size();
-            index = size == 0 ? 0 : randint<size_t>(1, size);
+            index = size == 0 ? 0 : rng->randint(1, size);
         } else
             index = 0;
     } else {
@@ -567,7 +572,7 @@ do_list_insert : {
             index = 0;
         } else if (str == "random") {
             size_t size = list->size();
-            index = size == 0 ? 1 : randint<size_t>(1, size);
+            index = size == 0 ? 1 : rng->randint(1, size);
         } else
             index = 0;
     } else {
@@ -594,7 +599,7 @@ do_list_replace : {
             index = list->size();
         else if (str == "random") {
             size_t size = list->size();
-            index = size == 0 ? 0 : randint<size_t>(1, size);
+            index = size == 0 ? 0 : rng->randint(1, size);
         } else
             index = 0;
     } else {
@@ -617,7 +622,7 @@ do_list_get_item : {
             index = list->size();
         else if (str == "random") {
             size_t size = list->size();
-            index = size == 0 ? 0 : randint<size_t>(1, size);
+            index = size == 0 ? 0 : rng->randint(1, size);
         } else
             index = 0;
     } else {

src/engine/virtualmachine_p.cpp

@@ -15,6 +15,7 @@ class IEngine;
 class Script;
 class Value;
 class List;
+class IRandomGenerator;
 
 struct VirtualMachinePrivate
 {
@@ -65,6 +66,8 @@ struct VirtualMachinePrivate
 
         Value **regs = nullptr;
         size_t regCount = 0;
+
+        static IRandomGenerator *rng;
 };
 
 } // namespace libscratchcpp

src/engine/virtualmachine_p.h

@@ -30,3 +30,4 @@ add_subdirectory(extensions)
 add_subdirectory(engine)
 add_subdirectory(clock)
 add_subdirectory(timer)
+add_subdirectory(randomgenerator)