debug/hex2bin.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       hex2bin.c
   4 /// \brief      Converts hexadecimal input strings to binary
   5 //
   6 //  Author:     Lasse Collin
   7 //
   8 //  This file has been put into the public domain.
   9 //  You can do whatever you want with this file.
  10 //
  11 ///////////////////////////////////////////////////////////////////////////////
  12
  13 #include "sysdefs.h"
  14 #include <stdio.h>
  15 #include <ctype.h>
  16
  17
  18 static int
  19 getbin(int x)
  20 {
  21         if (x >= '0' && x <= '9')
  22                 return x - '0';
  23
  24         if (x >= 'A' && x <= 'F')
  25                 return x - 'A' + 10;
  26
  27         return x - 'a' + 10;
  28 }
  29
  30
  31 int
  32 main(void)
  33 {
  34         while (true) {
  35                 int byte = getchar();
  36                 if (byte == EOF)
  37                         return 0;
  38                 if (!isxdigit(byte))
  39                         continue;
  40
  41                 const int digit = getchar();
  42                 if (digit == EOF || !isxdigit(digit)) {
  43                         fprintf(stderr, "Invalid input\n");
  44                         return 1;
  45                 }
  46
  47                 byte = (getbin(byte) << 4) | getbin(digit);
  48                 if (putchar(byte) == EOF) {
  49                         perror(NULL);
  50                         return 1;
  51                 }
  52         }
  53 }