disk_driver.h

#pragma once

#include "bitmap.h"
#include "common.h"
#include "disk_driver_structures.h"

/**
   The blocks indices seen by the read/write functions
   have to be calculated after the space occupied by the bitmap
*/

// creates the file
// allocates the necessary space on the disk
// calculates how big the bitmap should be
// compiles a disk header, and fills in the bitmap of appropriate size
// with all 0 (to denote the free space);
void DiskDriver_init(DiskDriver *disk, const char *filename, int num_blocks);

//loads an already initialized disk
int DiskDriver_load(DiskDriver *disk, const char *filename);

// reads the block in position block_num
// returns -1 if the block is free according to the bitmap
// 0 otherwise
int DiskDriver_readBlock(DiskDriver *disk, void *dest, int block_num);

// writes a block in position block_num, and alters the bitmap accordingly
// returns -1 if operation not possible
int DiskDriver_writeBlock(DiskDriver *disk, void *src, int block_num);

// frees a block in position block_num, and alters the bitmap accordingly
// returns -1 if operation not possible
int DiskDriver_freeBlock(DiskDriver *disk, int block_num);

// returns the first free block in the disk from position (checking the bitmap)
int DiskDriver_getFreeBlock(DiskDriver *disk, int start);

// writes the data (flushing the mmaps)
int DiskDriver_flush(DiskDriver *disk);

//cleaning up, used to close the file and the mapped object
void DiskDriver_shutdown(DiskDriver *disk);