SimpleFS/disk.cc at main · Henrique-T/SimpleFS · GitHub

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#include "disk.h"
#include <unistd.h>

Disk::Disk(const char *filename, int n)
{
	diskfile = fopen(filename, "r+");

	if (!diskfile)
		diskfile = fopen(filename, "w+");

	if (!diskfile)
	{
		cout << "Error when opening the file " << filename << "\n";
		return;
	}

	ftruncate(fileno(diskfile), n * DISK_BLOCK_SIZE);

	nblocks = n;
	nreads = 0;
	nwrites = 0;
}

int Disk::size()
{
	return nblocks;
}

void Disk::sanity_check(int blocknum, const void *data)
{
	if (blocknum < 0)
	{
		cout << "ERROR: blocknum (" << blocknum << ") is negative!\n";
		abort();
	}

	if (blocknum >= nblocks)
	{
		cout << "ERROR: blocknum (" << blocknum << ") is too big!\n";
		abort();
	}

	if (!data)
	{
		cout << "ERROR: null data pointer!\n";
		abort();
	}
}

void Disk::read(int blocknum, char *data)
{
	sanity_check(blocknum, data);

	fseek(diskfile, blocknum * DISK_BLOCK_SIZE, SEEK_SET);

	if (fread(data, DISK_BLOCK_SIZE, 1, diskfile) == 1)
	{
		nreads++;
	}
	else
	{
		cout << "ERROR: couldn't access simulated disk\n";
		abort();
	}
}

void Disk::write(int blocknum, const char *data)
{
	sanity_check(blocknum, data);

	fseek(diskfile, blocknum * DISK_BLOCK_SIZE, SEEK_SET);

	if (fwrite(data, DISK_BLOCK_SIZE, 1, diskfile) == 1)
	{
		nwrites++;
	}
	else
	{
		cout << "ERROR: couldn't access simulated disk\n";
		abort();
	}
}

void Disk::close()
{
	if (diskfile)
	{
		cout << nreads << " disk block reads\n";
		cout << nwrites << " disk block writes\n";
		fclose(diskfile);
		diskfile = 0;
	}
}

void Disk::setBitMap()
{
	/* Sets the size of bitmap = number of blocks */
	bitmap.resize(nblocks + 1);
	/* TODO:
	1. first block is the superblock. Therefore it's being used, therefore it's a 1.
	2. FOr the rest is zero.
	*/
}