common/memory_manager.h

#ifndef MEMORY_MANAGER_H
#define MEMORY_MANAGER_H

#include <stdint.h>
#include <stddef.h>

#ifdef ARDUINO
#include <Arduino.h>
#else
#include <cstdlib>
#include <memory>
#endif

/**
 * @brief Memory pool for embedded systems with limited heap
 * 
 * This class provides a simple memory pool implementation to avoid
 * heap fragmentation and provide predictable memory allocation.
 */
class MemoryPool {
private:
    static const size_t POOL_SIZE = 4096; // 4KB pool
    static const size_t MAX_BLOCKS = 32;
    
    struct Block {
        void* ptr;
        size_t size;
        bool in_use;
        uint32_t magic; // For corruption detection
    };
    
    uint8_t pool_memory[POOL_SIZE];
    Block blocks[MAX_BLOCKS];
    size_t next_free_offset;
    uint32_t allocation_count;
    uint32_t deallocation_count;
    
    static const uint32_t MAGIC_NUMBER = 0xDEADBEEF;
    
public:
    MemoryPool();
    ~MemoryPool();
    
    /**
     * @brief Allocate memory from the pool
     * @param size Size in bytes to allocate
     * @return Pointer to allocated memory or nullptr if failed
     */
    void* allocate(size_t size);
    
    /**
     * @brief Deallocate memory back to the pool
     * @param ptr Pointer to memory to deallocate
     * @return true if successful, false if invalid pointer
     */
    bool deallocate(void* ptr);
    
    /**
     * @brief Get memory usage statistics
     */
    struct MemoryStats {
        size_t total_size;
        size_t used_size;
        size_t free_size;
        uint32_t allocations;
        uint32_t deallocations;
        uint32_t active_blocks;
    };
    
    MemoryStats getStats() const;
    
    /**
     * @brief Check for memory corruption
     * @return true if memory is intact, false if corruption detected
     */
    bool checkIntegrity() const;
    
    /**
     * @brief Reset the entire pool (use with caution!)
     */
    void reset();
    
    /**
     * @brief Print memory usage information
     */
    void printStats() const;
};

/**
 * @brief RAII wrapper for automatic memory management
 * 
 * This template class provides automatic memory management
 * using RAII principles for embedded systems.
 */
template<typename T>
class SmartPtr {
private:
    T* ptr_;
    MemoryPool* pool_;
    bool owns_memory_;
    
public:
    /**
     * @brief Constructor for pool-allocated memory
     */
    explicit SmartPtr(MemoryPool* pool = nullptr) 
        : ptr_(nullptr), pool_(pool), owns_memory_(false) {
        if (pool_) {
            ptr_ = static_cast<T*>(pool_->allocate(sizeof(T)));
            if (ptr_) {
                new(ptr_) T(); // Placement new
                owns_memory_ = true;
            }
        }
    }
    
    /**
     * @brief Constructor taking ownership of existing pointer
     */
    SmartPtr(T* ptr, MemoryPool* pool, bool owns = true) 
        : ptr_(ptr), pool_(pool), owns_memory_(owns) {}
    
    /**
     * @brief Move constructor
     */
    SmartPtr(SmartPtr&& other) noexcept 
        : ptr_(other.ptr_), pool_(other.pool_), owns_memory_(other.owns_memory_) {
        other.ptr_ = nullptr;
        other.owns_memory_ = false;
    }
    
    /**
     * @brief Move assignment operator
     */
    SmartPtr& operator=(SmartPtr&& other) noexcept {
        if (this != &other) {
            reset();
            ptr_ = other.ptr_;
            pool_ = other.pool_;
            owns_memory_ = other.owns_memory_;
            other.ptr_ = nullptr;
            other.owns_memory_ = false;
        }
        return *this;
    }
    
    /**
     * @brief Destructor - automatically cleans up
     */
    ~SmartPtr() {
        reset();
    }
    
    /**
     * @brief Delete copy constructor and assignment (no copying)
     */
    SmartPtr(const SmartPtr&) = delete;
    SmartPtr& operator=(const SmartPtr&) = delete;
    
    /**
     * @brief Access the managed object
     */
    T* get() const { return ptr_; }
    T& operator*() const { return *ptr_; }
    T* operator->() const { return ptr_; }
    
    /**
     * @brief Check if the pointer is valid
     */
    bool isValid() const { return ptr_ != nullptr; }
    explicit operator bool() const { return isValid(); }
    
    /**
     * @brief Release ownership without destroying
     */
    T* release() {
        T* temp = ptr_;
        ptr_ = nullptr;
        owns_memory_ = false;
        return temp;
    }
    
    /**
     * @brief Reset the pointer, destroying current object if owned
     */
    void reset() {
        if (ptr_ && owns_memory_) {
            ptr_->~T(); // Explicit destructor call
            if (pool_) {
                pool_->deallocate(ptr_);
            }
        }
        ptr_ = nullptr;
        owns_memory_ = false;
    }
};

/**
 * @brief Buffer management class with bounds checking
 */
class SafeBuffer {
private:
    uint8_t* data_;
    size_t size_;
    size_t capacity_;
    MemoryPool* pool_;
    bool owns_memory_;
    
public:
    SafeBuffer(size_t capacity, MemoryPool* pool = nullptr);
    ~SafeBuffer();
    
    // Delete copy constructor and assignment
    SafeBuffer(const SafeBuffer&) = delete;
    SafeBuffer& operator=(const SafeBuffer&) = delete;
    
    // Move constructor and assignment
    SafeBuffer(SafeBuffer&& other) noexcept;
    SafeBuffer& operator=(SafeBuffer&& other) noexcept;
    
    /**
     * @brief Write data to buffer with bounds checking
     */
    bool write(const void* data, size_t size, size_t offset = 0);
    
    /**
     * @brief Read data from buffer with bounds checking
     */
    bool read(void* data, size_t size, size_t offset = 0) const;
    
    /**
     * @brief Append data to buffer
     */
    bool append(const void* data, size_t size);
    
    /**
     * @brief Clear buffer contents
     */
    void clear();
    
    /**
     * @brief Get buffer information
     */
    uint8_t* data() { return data_; }
    const uint8_t* data() const { return data_; }
    size_t size() const { return size_; }
    size_t capacity() const { return capacity_; }
    size_t available() const { return capacity_ - size_; }
    
    /**
     * @brief Check if buffer is valid
     */
    bool isValid() const { return data_ != nullptr; }
};

// Global memory pool instance
extern MemoryPool globalMemoryPool;

/**
 * @brief Convenience function to create smart pointers
 */
template<typename T>
SmartPtr<T> makeSmartPtr(MemoryPool* pool = &globalMemoryPool) {
    return SmartPtr<T>(pool);
}

/**
 * @brief Memory debugging macros (only active in debug builds)
 */
#ifdef DEBUG_MEMORY
#define MEM_ALLOC(size) globalMemoryPool.allocate(size)
#define MEM_FREE(ptr) globalMemoryPool.deallocate(ptr)
#define MEM_CHECK() globalMemoryPool.checkIntegrity()
#define MEM_STATS() globalMemoryPool.printStats()
#else
#define MEM_ALLOC(size) globalMemoryPool.allocate(size)
#define MEM_FREE(ptr) globalMemoryPool.deallocate(ptr)
#define MEM_CHECK() true
#define MEM_STATS() do {} while(0)
#endif

#endif // MEMORY_MANAGER_H