Crafting a Custom Memory Allocator in C++

Introduction

A custom memory allocator allows for fine-grained control over memory management in a program. In this exercise, we’ll implement a simple custom memory allocator using a memory pool approach.

Custom Memory Allocator: Memory Pool

A memory pool is a pre-allocated block of memory from which smaller chunks can be allocated and deallocated. This helps reduce fragmentation and provides faster allocation compared to the general-purpose malloc and free functions.

#include
#include

class Memory

Pool {
private:
    static const size_t POOL_SIZE = 10000;
    char* memory;

public:
    Memory

Pool() {
        memory = static_cast(std::malloc(POOL_SIZE));
        if (!memory) {
            std::cerr << "Memory allocation for pool failed\n";
            std::exit(EXIT_FAILURE);
        }
    }

    ~Memory

Pool() {
        std::free(memory);
    }

    void* allocate(size_t size) {
        // Simple allocation strategy: increment a pointer
        void* allocated

Memory = static_cast(memory);
        memory += size;

        if (memory - memory + size > POOL_SIZE) {
            std::cerr << "Memory pool exhausted\n";
            std::exit(EXIT_FAILURE);
        }

        return allocated

Memory;
    }

    // Optional: Implement a deallocate method
    // void deallocate(void* ptr) { /* Implement deallocation logic */ }
};

int main() {
    Memory

Pool pool;

    // Allocate memory from the pool
    int* int

Ptr = static_cast(pool.allocate(sizeof(int)));
    *int

Ptr = 42;

    std::cout << "Value stored in allocated memory: " << *int

Ptr << std::endl;

    return 0;
}

Explanation: 

• MemoryPool class represents a simple memory pool allocator.- The pool is initialized with a block of memory (POOL_SIZE) during construction.- The allocate method increments a pointer within the pool to allocate memory.- In a real-world scenario, a custom allocator might include more sophisticated allocation and deallocation strategies.

Compile and Run:

Compile and run the program using the following commands:

g++ -o custom_allocator custom_allocator.cpp
./custom_allocator

Exercise Extension:

Extend the exercise by implementing more advanced features, such as deallocation, block splitting, and merging.

Conclusion

Remember that custom memory allocators require careful consideration of thread safety and other performance considerations in a production environment. This exercise provides a basic understanding, and you can explore further improvements based on your requirements. Happy coding!