/***************************************************************************
 *   Copyright (C) 2004 by Derek Rabideau                                  *
 *   xsynackx@gmail.com                                                    *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/


#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

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

int checkargs(int argc, char *argFrom, char *argTo);
int convert(char argFrom, char *argNumber, char argTo);
int bintodec(char *argBin);
void printBin(int number);


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

  if (!checkargs(argc, argv[1], argv[3]))
    { printf("Error, wrong number of arguments.\n");
      return 0;
    }
    
    
    if(!convert(argv[1][0], argv[2], argv[3][0]))
      return EXIT_FAILURE;
  
  return EXIT_SUCCESS;
}

int checkargs(int argc, char *argFrom, char *argTo)
{

  if (argc != 4)
    return 0;

  if (argFrom[0] == '-')
  {
    argFrom[0] = argFrom[1];
    argFrom[1] = '\0';
  }
    
  if (argTo[0] == '-')
  {
    argTo[0] = argTo[1];
    argTo[1] = '\0';
  }
  return 1;
}

int convert(char argFrom, char *argNumber, char argTo)
{
int num;

  if (argFrom == 'd')
    num = strtol(argNumber, NULL, 10);
  
  else if (argFrom == 'x')
    num = strtol(argNumber, NULL, 16);
    
  else if (argFrom == 'o')
    num = strtol(argNumber, NULL, 8);
  
  else if (argFrom == 'a')
    num = argNumber[0];
    
  else if (argFrom == 'b')
    num = bintodec(argNumber);
    
  else
  {
    printf("ERROR:  Input form not implemented.\n");
    return 0;
    }
    if (argTo == 'x')
      printf("%#lx\n", num);
    
    else if (argTo == 'o')
      printf("%#lo\n", num);
      
    else if (argTo == 'a')
      { if (num < 32 || num > 126)
          printf("%lc   (The output is probably a nonprintable control character.)\n", num);
        else
          printf("%lc\n", num);}
        
    else if (argTo == 'd')
      printf("%ld\n", num);
      
    else if (argTo == 'b')
      printBin(num);
      
    else
      {printf("ERROR:  Conversion method not implemented.\n");
        return 0;
        }
    return 1;
      }

int bintodec(char *argBin)
{
  unsigned int super, place, length;
  unsigned long int dec;
  
  dec = 0;
  
  length = strlen(argBin) - 1;
  super = length;
  
  for (place = 0; place <= length; ++place)
  {
      if (argBin[place] != '0')
          dec += pow(2, super);
      --super;
  }
  
  return dec;
}

void printBin(int number)
{
double super;

super = 0;

while (pow(2,super) <= number)
{
++super;
}

--super;

while (super >= 0)
{
number -= pow(2, super);
printf("1");
--super;
    while(pow(2,super) > number && super >= 0)
    {
    printf("0");
    --super;
    }
}
    printf("\n");
}