Convert file

void Convert(char* pStr, int StrSize)
{
  // pStr is a pointer to text string to be converted
  // and should be checked before calling this to
  // make sure all chars are '0-9' 'a-f' A-F' space <CR> or <LF>

  char ch;
  char Byte;
  int NibbleCount = 0;

  for(int i = 0; i < StrSize; i++)
  {
    ch = pStr;

    // make sure we have a char
    if(ch != 0x0A && ch != 0x0D && ch != 0x20)
    {
      if            (ch >= '0' && ch <= '9')      ch -= '0';
      else if      (ch >= 'a' && ch <= 'f')      ch -= ('a' - 10);
      else if      (ch >= 'A' && ch <= 'F')      ch -= ('A' - 10);

      if(!(NibbleCount % 2))                  // Set lower nibble
      {
        Byte = (ch << 4);
      }
      else                                          // Set upper nibble
      {
        Byte += ch;
        printf("%c", Byte);
      }
      NibbleCount++;                        // increment for each nibble
    }
    else
      printf("%c",ch);                        // print <CR><LF> or Space

    pStr++;
  }
}