/** @file basesegment.H
 *  @brief Defines the base segment (0TB) class.
 */
#ifndef __KERNEL_BASESEGMENT_H
#define __KERNEL_BASESEGMENT_H

#include <kernel/segment.H>

// Forward declaration.
class MessageQueue;
class Block;

/** @class BaseSegment
 *  @brief Class to manage the base segment at 0 TB.
 *
 *  Contains a chain of blocks associated with the first segment.
 */
class BaseSegment : public Segment
{
    protected:
        /**
         * @brief Constructor.
         * Initialize attributes and set base addresss of segment to 0 TB.
         */
        BaseSegment() : Segment(0x0), iv_block(NULL) {};
        /**
         * @brief Destructor
         * Delete any blocks owned by this segment.
         */
        ~BaseSegment();

    public:
        /**
         * @brief Initialize the segment by allocating initial blocks and
         *        adding to the segment manager.
         */
        static void init();

        /**
         * @brief Implementation of the pure-virtual function from Segment.
         *
         * Calls block chain to deal with page fault.
         */
        bool handlePageFault(task_t* i_task, uint64_t i_addr);

        /**
         * @brief Allocates a block of virtual memory of the given size
         * @param i_mq[in] - Message queue to be associated with the block
         * @param i_va[in] - Base virtual address of the block to be allocated
         * @param i_size[in] - Requested virtual memory size of the block
         * @return int - 0 for successful block allocation, non-zero otherwise
         */
        static int mmAllocBlock(MessageQueue* i_mq,void* i_va,
                                uint64_t i_size);

    private:
        /**
         * @brief Internal implementation of init function.
         */
        void _init();

        /** Block-chain associated with this Segment. */
        Block* iv_block;

        /**
         * @brief Allocates a block of virtual memory of the given size
         * @param i_mq[in] - Message queue to be associated with the block
         * @param i_va[in] - Base virtual address of the block to be allocated
         * @param i_size[in] - Requested virtual memory size of the block
         * @return int - 0 for successful block allocation, non-zero otherwise
         */
        int _mmAllocBlock(MessageQueue* i_mq,void* i_va,uint64_t i_size);
};

#endif