//readmbr.c
//written by, Soni

#include <stdlib.h>
#include <stdio.h>

#include "mbr.h"

static void near * ptrMBR;

void showPartition(unsigned char (*)[]);

void main(int argc, char * argv[]){

   if( argc < TWO ){
      printf("argument required....\n%s < r | w | s >\n",argv[ZERO]);
      printf("r, HD read and floppy write,\n");
      printf("w, floppy read and HD write.\n");
      printf("s, Just shows the partition table.\n");
      printf("Written by soni.malik@gmail.com\n");
      return;
   }
   
   if( *argv[ONE] == ARGUMENT_ONE || *argv[ONE] == ARGUMENT_TWO || *argv[ONE] == ARGUMENT_THREE)
   ;
   else{
      printf("Nothing happend! allowed arguments are, r, w or s.\n");
      return;
   }


   if( ( ptrMBR = malloc(SIZE) ) == NULL ){ 
      printf("Unable to allocate memory in the near heap.\n");
      printf("Check the value of directive SIZE, if it is more than 0x0200,\n");
      printf("then decrease it by 0x0100 and then recompile.\n");
      return;
   }
   if(*argv[ONE] == ARGUMENT_THREE || *argv[ONE] == ARGUMENT_ONE)
   //reads MBR from the HD.
   //C drive is default. Change DRIVE_HD if you want other drive.
      readSector(ptrMBR, DRIVE_HD + HEAD, CYLINDER + SECTOR_ONE, SECTORS);

   if(*argv[ONE] == ARGUMENT_TWO)
   //reads MBR from the FD.
   //A drive is default. Change DRIVE_FD for other drive.
      readSector(ptrMBR, DRIVE_FD + HEAD, TRACK + SECTOR_ONE, SECTORS);

   //check if what is read, is MBR.
   if( ((unsigned char *)ptrMBR)[SYMBOLAINDEX] == SYMBOLA && ((unsigned char *)ptrMBR)[SYMBOLBINDEX] == SYMBOLB )
      printf("read MBR....\n");
   else{
      printf("unable to read MBR, returning\n");
      return;
   }

   if( *argv[ONE] == ARGUMENT_THREE ){
      showPartition((unsigned char (*)[])((char *)ptrMBR + 0x01be) );
      return;
   }

   if( *argv[ONE] == ARGUMENT_ONE )
   //writes MBR to the FD.
   //A drive is default. Change DRIVE_FD for other drive.
      writeSector(ptrMBR, DRIVE_FD + HEAD, TRACK + SECTOR_ONE, SECTORS);
   if( *argv[ONE] == ARGUMENT_TWO )
   //writes MBR to the HD.
   //C drive is default. Change DRIVE_HD if you want other drive.
      writeSector(ptrMBR, DRIVE_HD + HEAD, CYLINDER + SECTOR_ONE, SECTORS);
   //I'm assuming that the MBR is written, 
   //to make sure that it should happen, put a floppy in the drive before,
   //the execution of this program.
   printf("written MBR....\n");
   printf(":)\n");

}

void showPartition(unsigned char (*tables)[16]){
   int count = 0;
   unsigned int Scyl = 0;
   unsigned int Ssec = 0;
   unsigned int Ecyl = 0;
   unsigned int Esec = 0;
   unsigned long Rsec = 0;
   printf("Partition table.\n");
   printf("Boot Shead Scyl Ssec sys Ehead Ecyl Esec Rsec     size(Sec)\n");
   for(count=0; count<4; count++){
      Scyl      = ((*((unsigned int *)(tables[count] + 2)) & 0x00c0) << 2) + tables[count][3];
      Ssec      = tables[count][2] & 0x003f;
      Ecyl      = ((*((unsigned int *)(tables[count] + 6)) & 0x00c0) << 2) + tables[count][7]; 
      Esec      = tables[count][6] & 0x003f;
      Rsec = *((unsigned long *)(tables[count] + 8));
      printf("%.2x   %.2d    %.4d %.2d   %.2x  %2d    %.4d %.2d   %.8ld %.8ld\n",tables[count][0], tables[count][1], Scyl, Ssec, tables[count][4], tables[count][5], Ecyl, Esec, Rsec, *((unsigned long *)(tables[count] +12)) );
   }

}