// Practic1Lab1.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
// ossp01.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include "pch.h"
struct BPB {
	WORD sectorSize;
	BYTE clusterSize;
	WORD reservedSectors;
	BYTE fatCount;
	WORD rootSize;
	WORD totalSectors;
	BYTE media;
	WORD fatSize;
	WORD sectors;
	WORD heads;
	WORD hiddenLow;
	WORD hiddenHigh;
	BYTE largeTotalSectors[4];
};

struct bootRecord {
	BYTE jmpCommand[3];
	BYTE vendorName[8];
	BPB extendedBlock;
	BYTE drivePhysicalNumber;
	BYTE rezerved;
	BYTE symbolBrackets;
	BYTE volumeSerialNumber[4];
	BYTE volumeLabel[11];
	BYTE identifierFAT[8];
	BYTE bootCode[450];
} boot;

typedef struct root_Entries
{
	BYTE short_FileName[11];
	BYTE fileAttributes;
	BYTE reserved;
	BYTE createTime_ms;
	WORD createTime;
	WORD createDate;
	WORD accessedDate;
	WORD clusterNumber_High;
	WORD modifiedTime;
	WORD modifiedDate;
	WORD firstClusterAddress_FAT12;
	DWORD sizeofFile;
} root;

void ScanBootSector();
void ScanRoot();
void ScanFat();

WORD FAT[2880];
BYTE Buffer[512 * 9];
WORD* Val;
HANDLE hDisk;

int main()
{
	hDisk = CreateFile(TEXT("C:\\Tmp\\Dos6.22.img"),    // drive to open
		GENERIC_READ,                     // Access mode
		FILE_SHARE_READ,                  // Share Mode
		NULL,                             // Security Descriptor
		OPEN_EXISTING,                    // How to create
		0,                                // File attributes
		NULL);                            // Handle to template
	if (hDisk != NULL)
	{
		ScanBootSector();
		ScanRoot();
		ScanFat();
		int cluster = 2619;
		int count = 1;
		while (FAT[cluster] != 0xfff)
		{
			printf("%6x\t", FAT[cluster]);
			cluster = FAT[cluster];
			count++;
		}
		printf("\n%d", count);
	}
	CloseHandle(hDisk);

	return 0;
}

void ScanFat() {
	DWORD dwBytesRead;
	WORD fatElement;
	int j = 0;
	SetFilePointer(hDisk, 512, NULL, FILE_BEGIN);
	ReadFile(hDisk, Buffer, 512 * 9, &dwBytesRead, NULL);
	if (Buffer[0] != boot.extendedBlock.media) {
		printf("Error 1 \n");
		return;
	}
	//FAT table entries are packed so that two cluster entries occupy three bytes with the following general format :
	//yz Zx XY
    //	where
	//	xyz is the one pointer entry and
	//	XYZ is the second pointer entry.
	//	E.g., bytes :
	//  2d e0 02
	//	refer to clusters 0x02d (45) and 0x02e (46)
	
	for (int i = 0, j = 0; i < 512 * 9; i += 3, j += 2) {		
		FAT[j] = (Buffer[i] + (Buffer[i + 1] << 8)) & 0x0FFF;
		FAT[j+1] = (Buffer[i + 1] + (Buffer[i + 2] << 8)) >> 4;
	}	
}

void ScanRoot() {
	DWORD dwFilePointer;
	DWORD dwBytesRead;
	root stRoot;
	BYTE byteRoot[512];
	memset(&byteRoot, 0, 512);
	dwFilePointer = SetFilePointer(hDisk, (512 * 19), NULL, FILE_BEGIN);
	if (dwFilePointer == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR)
	{
		// Deal with failure
		// . . .

	} // End of error handler
	int iSector = 19;
	BOOL bNoEntry = FALSE;
	// Iterate through root directory sectors
	do
	{
		if (!ReadFile(hDisk, byteRoot, 512, &dwBytesRead, NULL))
		{
			printf("Error in Reading Root Entry.\n");
		}
		else
		{
			BYTE *pByteRoot = byteRoot;
			// Iterate through 32 byte entries
			for (int i = 0; i < (512 / 32); i++)
			{
				ZeroMemory(&stRoot, 32);
				memcpy(&stRoot, pByteRoot, 32);

				// No entry beyond this used.
				if (stRoot.short_FileName[0] == 0x00)
				{
					// Stop iteration
					bNoEntry = TRUE;
					break;
				}
				else
				{
					// This if loops checks for file deletion
					// status
					if (stRoot.short_FileName[0] == 0xE5)
					{
						printf("First character of file after deletion :0x%x\n",
							stRoot.short_FileName[0]);
						printf("File status: Deleted.\n");
					}


					puts("File Name            :");
					for (size_t idx = 0; idx < 8; idx++)
					{
						putchar(stRoot.short_FileName[idx]);
					}
					putchar('\n');
					if (stRoot.fileAttributes & 0x01)
						printf("File Attribute       : Read Only File\n");
					if (stRoot.fileAttributes & 0x02)
						printf("File Attribute    : Hidden File\n");
					if (stRoot.fileAttributes & 0x04)
						printf("File Attribute    : System File\n");
					if (stRoot.fileAttributes & 0x08)
						printf("File Attribute    : Volume Label\n");
					if (stRoot.fileAttributes & 0x0f)
						printf("File Attribute    : Long File Name\n");
					if (stRoot.fileAttributes & 0x10)
						printf("File Attribute    : Directory\n");
					if (stRoot.fileAttributes & 0x20)
						printf("File Attribute    : Archive\n");

					WORD nYear = (stRoot.createDate >> 9);
					WORD nMonth = (stRoot.createDate << 7);
					nMonth = nMonth >> 12;
					WORD nDay = (stRoot.createDate << 11);
					nDay = nDay >> 11;

					//printf("Create Date    : %d/%d/%d\n", nDay, nMonth, (nYear + 1980));

					nYear = (stRoot.modifiedDate >> 9);
					nMonth = (stRoot.modifiedDate << 7);
					nMonth = nMonth >> 12;
					nDay = (stRoot.modifiedDate << 11);
					nDay = nDay >> 11;

					printf("Modification Date    : %d/%d/%d\n", nDay, nMonth, (nYear + 1980));

					nYear = (stRoot.accessedDate >> 9);
					nMonth = (stRoot.accessedDate << 7);
					nMonth = nMonth >> 12;
					nDay = (stRoot.accessedDate << 11);
					nDay = nDay >> 11;

					//printf("Accessed Date        : %d/%d/%d\n", nDay, nMonth, (nYear + 1980));

					printf("Start Cluster Address: %d\n",
						stRoot.firstClusterAddress_FAT12);
					printf("File Size            : %d bytes\n",
						stRoot.sizeofFile);
					pByteRoot += 32;
				}    // End of else
			}

			if (bNoEntry)
				break;
			else
			{
				iSector += 1;
			}
		}
	} while (iSector <= 33);

}

void ScanBootSector()
{

	DWORD dwBytesRead;
	char str[128];
	unsigned short num1, num2;
	bool check;

	check = ReadFile(hDisk, (void *)&boot, sizeof(bootRecord), &dwBytesRead, NULL);
	if (!check) {
		printf("Error %d", GetLastError());
	}
	strncpy_s(str, (char *)boot.vendorName, 8);
	str[8] = '\0';
	printf("Vendor Name: %s\n", str);

	if (boot.drivePhysicalNumber >= 0x80)
		puts("Hard disk");
	else
		puts("Floppy disk");
	if (boot.symbolBrackets == '(')
		puts("Extended block present.");
	else
		puts("Extended block absent.");
	memcpy(&num1, boot.volumeSerialNumber, 2);
	memcpy(&num2, boot.volumeSerialNumber + 2, 2);
	printf("Serial num=%X-%X\n", num1, num2);

	strncpy_s(str, (char *)boot.volumeLabel, 11);
	str[11] = '\0';
	printf("Label: %s\n", str);

	strncpy_s(str, (char *)boot.identifierFAT, 8);
	str[8] = '\0';
	printf("Ident FAT: %s\n", str);

	//printf("%d", sizeof(struct param_bios));
	/*printf("Byte in sector = %d\n", boot.extendedBlock.sectorSize);
	printf("Sector in cluster = %d\n", boot.extendedBlock.clusterSize);
	printf("Reserved sector = %d\n", boot.extendedBlock.reservedSectors);
	printf("FAT Count = %d\n", boot.extendedBlock.fatCount);
	printf("root size = %d\n", boot.extendedBlock.rootSize);
	printf("Total sector = %d\n", boot.extendedBlock.totalSectors);
	printf("Media = %d\n", boot.extendedBlock.media);
	printf("Fat size = %d\n", boot.extendedBlock.fatSize);
	printf("Sectors = %d\n", boot.extendedBlock.sectors);
	printf("Heads = %d\n", boot.extendedBlock.heads);
	printf("hidden Low = %d\n", boot.extendedBlock.hiddenLow);
	printf("hidden High  = %d\n", boot.extendedBlock.hiddenHigh);
	printf("largeTotal Sectors = %d\n", boot.extendedBlock.largeTotalSectors[4]);*/
		
}