Add RandomGenerator class

Author: adazem009

src/engine/CMakeLists.txt

@@ -19,4 +19,7 @@ target_sources(scratchcpp
     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/irandomgenerator.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/randomgenerator.cpp

@@ -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.h

@@ -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

test/CMakeLists.txt

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

test/mocks/randomgeneratormock.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <engine/internal/irandomgenerator.h>
+#include <gmock/gmock.h>
+
+using namespace libscratchcpp;
+
+class RandomGeneratorMock : public IRandomGenerator
+{
+    public:
+        MOCK_METHOD(long, randint, (long, long), (const, override));
+        MOCK_METHOD(double, randintDouble, (double, double), (const, override));
+};

test/randomgenerator/CMakeLists.txt

@@ -0,0 +1,12 @@
+add_executable(
+  randomgenerator_test
+  randomgenerator_test.cpp
+)
+
+target_link_libraries(
+  randomgenerator_test
+  GTest::gtest_main
+  scratchcpp
+)
+
+gtest_discover_tests(randomgenerator_test)

test/randomgenerator/randomgenerator_test.cpp

@@ -0,0 +1,45 @@
+#include <engine/internal/randomgenerator.h>
+
+#include "../common.h"
+
+using namespace libscratchcpp;
+
+TEST(RandomGeneratorTest, RandInt)
+{
+    auto rng = RandomGenerator::instance();
+    ASSERT_TRUE(rng);
+
+    long num;
+
+    for (int i = 0; i < 25; i++) {
+        num = rng->randint(-2, 3);
+        ASSERT_GE(num, -2);
+        ASSERT_LE(num, 3);
+    }
+
+    for (int i = 0; i < 25; i++) {
+        num = rng->randint(5, -3);
+        ASSERT_GE(num, -3);
+        ASSERT_LE(num, 5);
+    }
+}
+
+TEST(RandomGeneratorTest, RandIntDouble)
+{
+    auto rng = RandomGenerator::instance();
+    ASSERT_TRUE(rng);
+
+    long num;
+
+    for (int i = 0; i < 1000; i++) {
+        num = rng->randintDouble(-2.23, 3.875);
+        ASSERT_GE(num, -2.23);
+        ASSERT_LE(num, 3.875);
+    }
+
+    for (int i = 0; i < 1000; i++) {
+        num = rng->randintDouble(5.081, -2.903);
+        ASSERT_GE(num, -2.903);
+        ASSERT_LE(num, 5.081);
+    }
+}