io.h

// *******************************
// FILE: 		io.h
// AUTHOR:		SharpCoder
// DATE:		2015-03-31
// ABOUT:		This is the disk IO header. It must be implemented
// 				in order for the filesystem to work.
//
// LICENSE:		Provided "AS IS". USE AT YOUR OWN RISK.
// *******************************

#ifndef __PIFS_IO_H_
#define __PIFS_IO_H_

#include "conf.h"
#include "../libs/mem.h"

// These are the IO methods used to simulate writing to a disk.
// For now, we will simply use memory. Since we're the kernel,
// we can do that!
int openDisk(int nbytes);
int readBlock(int disk, int blocknr, void* buf, int bytes);
int writeBlock(int disk, int blocknr, void* block, int bytes, uint32 foffset);
void syncDisk();

// Create the disk
char* disk_base;

// Allocate some disk.
int f_mkfs( int nbytes ) {
	// Wipe the memory.
	disk_base = (char*)malloc(nbytes);
	return 1;
}

int readBlock(int disk, int blocknr, void* buf, int bytes) {
	
	char* addr = (char*)disk_base;
	char* targ = (char*)buf;
	
	// Add the offset to the address.
	addr += blocknr * PAGE_SIZE;
	
	// Check for a buffer overflow type situation.
	if ( bytes > PAGE_SIZE ) return -1;
	
	for ( uint32 index = 0; index < bytes; index++ ) {
		*targ = *addr;
		targ++;
		addr++;
	}
	return 1;
}
 
int writeBlock(int disk, int blocknr, void* buf, int bytes, uint32 foffset) {
	
	char* addr = (char*)disk_base;
	char* orig = (char*)buf;
	
	// Add the offset to the address.
	addr += blocknr * PAGE_SIZE;
	addr += foffset;
	
	// Check for a buffer overflow type situation.
	if ( bytes > PAGE_SIZE ) return -1;
	
	for ( uint32 index = 0; index < bytes; index++ ) {
		*addr = *orig;
		orig++;
		addr++;
	}
		
	return 1;
}
void syncDisk() {
	
}

#endif