init commit

lectures/DataBuffer-Data.cpp

@@ -0,0 +1,110 @@
+#include <iostream>
+#include <cstring>
+
+int increment_counter() {
+    static int counter = 0;
+    return counter++;
+}
+
+struct Data {
+public:
+    int value;
+    Data(int x = 42) : value(x) {}
+    Data(const Data& data) {
+        value = data.value;
+    }
+    ~Data() {
+        // std::cout << "~Data() called " << std::endl;
+        increment_counter();
+    }
+    Data& operator=(const Data& data) {
+        value = data.value;
+
+        return *this;
+    }
+    friend std::ostream& operator<<(std::ostream& os, const Data data) {
+        os << data.value;
+        return os;
+    }
+};
+
+class DataBuffer {
+    Data* addr;
+    size_t size_buf;
+    friend void std::swap(DataBuffer& a, DataBuffer& b);
+public:
+    DataBuffer(size_t size) {
+        // std::cout << "called11!" << std::endl;
+        size_buf = size;
+        addr = new Data[size_buf];
+    }
+    DataBuffer(const DataBuffer& data_buf) = delete;
+    const DataBuffer& operator=(const DataBuffer& data_buf) = delete;
+    DataBuffer(DataBuffer&& data_buf) noexcept : addr(data_buf.addr), size_buf(data_buf.size_buf) {
+        // std::cout << "Move constructor called!" << std::endl;
+        data_buf.addr = nullptr;
+        data_buf.size_buf = 0;
+    }
+    DataBuffer& operator=(DataBuffer&& data_buf) noexcept {
+        // std::cout << "Move assignment operator called!" << std::endl;
+        if (this != &data_buf) {
+            delete[] addr;
+            addr = data_buf.addr;
+            size_buf = data_buf.size_buf;
+            data_buf.addr = nullptr;
+            data_buf.size_buf = 0;
+        }
+        return *this;
+    }
+    ~DataBuffer() {
+        // std::cout << "called1!" << std::endl;
+        delete[] addr;
+    }
+    size_t size() const {
+        return size_buf;
+    }
+    Data& operator[](const size_t ind) {
+        return addr[ind];
+    }
+    const Data& operator[](const size_t ind) const {
+        return addr[ind];
+    }
+};
+
+namespace std {
+    template<>
+    void swap<DataBuffer>(DataBuffer& a, DataBuffer& b) {
+        std::swap(a.addr, b.addr);
+        std::swap(a.size_buf, b.size_buf);
+    }
+}
+
+void print_buffer(const DataBuffer& buffer) {
+    for (size_t i = 0; i < buffer.size(); i++)
+        std::cout << "buffer[" << i << "] == " << buffer[i] << std::endl;
+}
+
+int main() {
+    {
+        DataBuffer buffer_1{ 5 }, buffer_2{ 3 };
+
+        std::cout << "buffer_1.size() == " << buffer_1.size() << std::endl;
+        std::cout << "buffer_2.size() == " << buffer_2.size() << std::endl;
+
+        for (size_t i = 0; i < buffer_2.size(); i++)
+            buffer_2[i] = i + 1;
+
+        std::cout << "buffer_1[0] == " << buffer_1[0].value << std::endl;
+        std::cout << "buffer_2[0] == " << buffer_2[0].value << std::endl;
+
+        std::swap(buffer_1, buffer_2);
+        // DataBuffer buffer_copy = buffer_1; // forbidden!
+
+        std::cout << "buffer_1.size() == " << buffer_1.size() << std::endl;
+        std::cout << "buffer_2.size() == " << buffer_2.size() << std::endl;
+
+        print_buffer(buffer_1);
+    }
+    std::cout << "~Data() called " << increment_counter() << " times" << std::endl;
+    return 0;
+}