1 /**

     2  * $Id: decimal.c,v 1.1.1.1 2008-04-28 17:32:52 mbroeker Exp $

     3  * $Source: /development/c/asm/decimal.c,v $

     4  *

     5  */

     6 

     7 #include <stdio.h>

     8 #include <stdlib.h>

     9 #include <string.h>

    10 #include <limits.h>

    11 

    12 #define  MAXBITS __WORDSIZE

    13 #define  MAXVALUE ULONG_MAX

    14 

    15 typedef unsigned long int ULONG;

    16 

    17 void usage (char *name)

    18 {

    19     printf ("Usage: %s start [end] [base]\n", name);

    20 }

    21 

    22 /*

    23  * Computes the binary representation of a

    24  * decimal value and returns the result

    25  * in proper order and the number of digits

    26  */

    27 

    28 char *dec_to_base (ULONG decimal, int base, int *digits)

    29 {

    30     char *encoded;

    31     char swp;

    32     int i;

    33 

    34     i = 0;

    35 

    36     if ((decimal > MAXVALUE)) {

    37         perror ("VALUE TOO BIG");

    38         return NULL;

    39     }

    40 

    41     if ((encoded = malloc ((MAXBITS) * sizeof (char))) == NULL) {

    42         perror ("MALLOC ERROR");

    43         return NULL;

    44     }

    45 

    46     while (decimal > base - 1) {

    47         encoded[i++] = (decimal % base);

    48         decimal /= base;

    49     }

    50     encoded[i++] = (decimal % base);

    51     *digits = i;

    52 

    53     for (i = 0; i < *digits - 1; i++) {

    54         swp = encoded[*digits - i - 1];

    55         encoded[*digits - i - 1] = encoded[i];

    56         encoded[i] = swp;

    57     }

    58 

    59     return encoded;

    60 }

    61 

    62 int main (int argc, char **argv)

    63 {

    64     ULONG decimal, start, end;

    65     int bits, base, i;

    66     char *binaer;

    67 

    68     base = 2;

    69 

    70     if (argc == 2) {

    71         start = atol (argv[1]);

    72         end = start + 1;

    73     } else if (argc == 3) {

    74         start = atol (argv[1]);

    75         end = atol (argv[2]);

    76     } else if (argc == 4) {

    77         start = atol (argv[1]);

    78         end = atol (argv[2]);

    79         base = atoi (argv[3]);

    80     } else {

    81         usage (argv[0]);

    82         return EXIT_SUCCESS;

    83     }

    84 

    85     if (!((start >= 0) && (end > start) && (base > 1))) {

    86         usage ("Trottel");

    87         printf ("%ld\t%ld\t%d\n", start, end, base);

    88         return EXIT_SUCCESS;

    89     }

    90 

    91     printf ("\tVALUE \t\tDIGITS\t\t Encoded\n");

    92     printf ("----------------------------------------------------\n");

    93 

    94     for (decimal = start; decimal < end; decimal++) {

    95         if ((binaer = dec_to_base (decimal, base, &bits)) == NULL) {

    96             return EXIT_FAILURE;

    97         }

    98 

    99         printf ("%12ld %12d \t\t", decimal, bits);

   100 

   101         for (i = 0; i < bits; i++) {

   102             printf ("%X", binaer[i]);

   103         }

   104         printf ("\n");

   105 

   106         if (binaer)

   107             free (binaer);

   108     }

   109     return EXIT_SUCCESS;

   110 }